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LATEST ENSO UPDATE PLUS SOME COMMENTS ON THE 2018 HURRICANE SEASON

 

Hello folks, this is to let you know that I've just posted a report with the title shown above on the teleconnections thread.  It's about ENSO and sea surface temperatures but includes some comments on the 2018 hurricane season where I feel that recent evidence suggests a well below average number of named storms and very few major hurricanes. Conditions are much more conducive to cyclone development in the tropical east Pacific and one or two of these may make their way across central America and into the Gulf of Mexico which is warmer than average. 

 

Here's one chart to whet your appetite:

en10.PNG

 

 

Here's the link to the full report (it's currently at the bottom of page 3):

 

https://www.33andrain.com/topic/868-teleconnections-a-more-technical-discussion/?page=3&tab=comments#comment-84780

 

We have also added many more papers into the Teleconnection Research Portal  (just click on the words for a direct link).  During the last 2 weeks I have focused on hurricanes and their causes with papers and video presentations on the African Easterly Wave, the AMO (Atlantic Multi-decadal Oscillation) and ENSO.  These range from general guides to more advanced topics. You are very welcome to browse and explore the portal where we hope that there is something for everyone

 

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MONITORING HURRICANE AND TROPICAL STORM ACTIViTY - LINKS TO SATELLITE IMAGERY

 

Further to my recent ENSO, SST and Hurricane post on the teleconnections thread (plugged above on this thread) I thought that "some" members who use this thread may not be aware of "some" of the excellent sites that are available for monitoring developments of disturbances, tropical storms and hurricane tracks.  In particular we need to watch those "African Easterly Waves" (AEWs) which account for the vast majority of Atlantic hurricanes and almost all the major ones.  Like many of you, I regularly use the main NOAA Hurricane site - so let's start with that:    https://www.nhc.noaa.gov/

 

Her'es the current Atlantic image (it auto updates):

 

two_atl_2d0.png

https://www.nhc.noaa.gov/gtwo.php?basin=atlc&fdays=2

 

One can view Atlantic and east Pacific storms and read the wirtten NOAA updates.  Here's the current east Pacific chart (auto updates):

two_pac_2d0.png

https://www.nhc.noaa.gov/gtwo.php?basin=epac&fdays=2

 

 

Here's a link to the NOAA satelitte menu page for NOAA and "non NOAA" sites with many options:

 

https://www.nhc.noaa.gov/satellite.php 

 

If one uses the "loop" options you can obtain some brilliant animations which show the rate of developments/decay and westward progress - these charts really help the forecasters on intensity, tracks and timing. "gif downloads" are available - EDIT: I tried posting one here and it remained active for 24 hours but would need updating - so best to check the site yourself on this link:

 

https://www.star.nesdis.noaa.gov/GOES/GOES16_FullDisk_Band.php?band=GEOCOLOR&length=24 

 

This is an example of one of their images that can be animated on the site:

20181850315_GOES16-ABI-FD-GEOCOLOR-1808x 

 

Further examples and links: 

 

https://cdn.star.nesdis.noaa.gov/GOES16/ABI/SECTOR/taw/02/1800x1080.jpg 

 

https://cdn.star.nesdis.noaa.gov/GOES16/ABI/FD/GEOCOLOR/678x678.jpg  

 

https://cdn.star.nesdis.noaa.gov/GOES16/ABI/SECTOR/taw/GEOCOLOR/1800x1080.jpg 

 

http://www.goes.noaa.gov/f_meteo.html  (specialist)

 

http://www.goes.noaa.gov/FULLDISK/GMIR.JPG  (example)

 

http://www.ssd.noaa.gov/imagery/  (further image menu)

 

https://weather.com/maps/satellite/europe-africaweathermap

 

https://www.weatheronline.co.uk/weather/satellite/Africa/West/Infraredcolor.htm

 

There are more sites and links (many are subscription sites) but this "free to view" selection and options should provide a good overall coverage - unless you know better?  David  :)  

 

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On 7/3/2018 at 11:42 AM, Bring Back 1962-63 said:

MONITORING HURRICANE AND TROPICAL STORM ACTIViTY - LINKS TO SATELLITE IMAGERY

 

Further to my recent ENSO, SST and Hurricane post on the teleconnections thread (plugged above on this thread) I thought that "some" members who use this thread may not be aware of "some" of the excellent sites that are available for monitoring developments of disturbances, tropical storms and hurricane tracks.  In particular we need to watch those "African Easterly Waves" (AEWs) which account for the vast majority of Atlantic hurricanes and almost all the major ones.  Like many of you, I regularly use the main NOAA Hurricane site - so let's start with that:    https://www.nhc.noaa.gov/

 

(SNIPPED)

 

 

Hi David. The role of 'African Easterly Waves' in tropical cyclone and hurricane development is clearly key and a very interesting topic - thank you for the papers you've been placing in the Research Portal. For example, here's an extract from the latest gem you've posted:

 

Do West African thunderstorms predict the intensity of Atlantic hurricanes?

Since 85% of all major Atlantic hurricanes originate as thunderstorm clusters in equatorial Africa, we have investigated the connection between these African thunderstorms and the consequent development of these disturbances into tropical storms.
Link to Research Portal: https://www.33andrain.com/topic/1223-do-west-african-thunderstorms-predict-the-intensity-of-atlantic-hurricanes/

 

Btw, there's a nice easy read about AEWs here and I can add it to the portal if you wish. Here's a couple of illustrations from the article:

 

African Easterly Wave Example.jpgAfrican Easterly Wave Example 2.jpg

 

As well as the links you provided above I find the satellite images from https://en.sat24.com/en/af to be very good in keeping a watching brief on AEW development across the key Regions of Africa. For example, here's how cloud and precipitation developments were looking on Weds evening July 4th:

 

Africa Sat Image Cloud 04July2018 19.15.jpgAfrica Sat Image Precip 04July2018 19.00.jpg

 

But whilst the AEWs might be the seeds for hurricane development, as they exit Africa into the Atlantic the SSTs then play their role in 'feeding' the disturbance so it develops into a hurricane. So as you've also posted above, of great interest atm is the anomalously cool SSTs in the Atlantic and in particular the Main Development Region (MDR) for hurricanes which in large areas is 1C cooler than normal. This is now shaping up to be an important factor in subduing hurricane activity this season. Here's the latest anomaly from NOAA on June 28th and for comparison the same chart from back in January:

 

NOAA SST Anom 28June2018.jpgNOAA SST Anom 29Jan2018.jpg

 

The cooler SSTs in the Atlantic are reflective of the Atlantic Multidecadel Oscillation (AMO) index turning negative, indicating a transition from warm to cold phase. I'll be discussing this in a post on the Teleconnections thread over the coming days and cross referencing on here. As I posted earlier in this thread, the cold phase of the AMO is associated with low hurricane activity eras.

 

 

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10 hours ago, Blessed Weather said:

 

Hi David. The role of 'African Easterly Waves' in tropical cyclone and hurricane development is clearly key and a very interesting topic - thank you for the papers you've been placing in the Research Portal. For example, here's an extract from the latest gem you've posted:

 

Do West African thunderstorms predict the intensity of Atlantic hurricanes?

Since 85% of all major Atlantic hurricanes originate as thunderstorm clusters in equatorial Africa, we have investigated the connection between these African thunderstorms and the consequent development of these disturbances into tropical storms.
Link to Research Portal: https://www.33andrain.com/topic/1223-do-west-african-thunderstorms-predict-the-intensity-of-atlantic-hurricanes/

 

Btw, there's a nice easy read about AEWs here and I can add it to the portal if you wish. Here's a couple of illustrations from the article:

 

(SNIPPED)

 

That's a great post Malcolm and thank you for your kind comments.  Yes, I added many important "hurricane related" papers into the Research Portal during the last few days and I have another 50+ papers to add in the coming days.  Some of these are very recent indeed. My mind is boggling and I'm suffering from reports, charts and data overload ?.  There are fascinating accounts of AEWs (African Easterly Waves), the AMO (Atlantic Multidecadal Oscillation), AMOC (Atlantic Meridional Overturning Circulation) and others related to the tropical Atlantic and east Pacific SSTs (sea surface temperatures).  Some of these are pretty technical while others are easy reads.  There are a number of conference short video presentations and I have a load of these to add later today.  

 

We have a slight dilemma - whether to post on this "2018 Atlantic Hurricane Season" thread or the "Teleconnections - A More technical Discussion" thread.  Any posts on the teleconnections and reviews of papers need to go into that thread as a "permanent" record for future reference.  Anything related to the "current" hurricane season should go on here. There is an overlap and as we have both already done,  we can either post on the tele thread and put a short plug on here or cross post on both threads.  I hope that other forum members who are interested in these topics get involved too and you will all be very welcome to post on the tele thread too.

 

Re: that "easy read AEW" short paper you refer to - yes it's excellent and it definitely belongs in the portal.  It's part of a longer paper which is from the "Comet Program" - do you have the "full" details?  If not, I do (it was in my stock of papers to add but I'm more than happy for you to do so).  I registered with Comet several months ago (it's free) and that very long post I did on the 2018 SSW and Mountain Torque included a sequence of charts on "Mountain Waves" and they came from Comet. They are an educational group specialising in "environmental science"and have been active since 1989 - based in Boulder, Colorado.  I have a whole range of their excellent papers and guides to place in the portal in due course.  They produce some superb charts.  Here's the link to the full AEW paper:   

 

https://www.meted.ucar.edu/tropical/synoptic/Afr_E_Waves/navmenu.php?tab=1&page=2.0.0&type=flash    

 

and here's the link to the homepage of their site:   http://comet.ucar.edu/    (for free access, you'll need to register with "MetEd" - part of their group; which links from their homepage).

 

Back to the current position - I feel that we have reached a key stage in the hurricane season.  Those "full Africa" satellite images you posted are excellent. Some of these charts need to be posted on here regularly during the main part of the season.  There are so many SST charts available from NOAA (including the ones you just posted) and several other sources.  That reminds me, I forgot to include an important link to animated SST charts.  The one I posted on Saturday (shown on here and as part of my main post on the tele thread) also comes from the NOAA/NHC site -  the "Reynolds SST Analysis". Here's the link:   https://www.nhc.noaa.gov/sst/

 

This includes current SST charts (updated daily but with a 1 day time lag) for the tropical Atlantic and east Pacific and you can go back 7 days. The same goes for the anomalies. Here are four current examples:

 

1. SSTs for 3rd July, 2018

hur1.PNG

 

2.  SSTs for 30th June, 2018

hur2.PNG

 

3. SST 7 Day Anomalies for 3rd July, 2018

hur4.PNG

 

4. SST 7 Day Anomalies for 30th June, 2018

hur3.PNG

 

Most useful of all are the "animation loop" charts. There is no gif option, so these charts cannot be copied on here in their animation form (they may be available from another source?) but you can stop the run through to freeze and copy any chart in the loop. I strongly recommend regularly viewing these animated charts on the NOAA site as they give a real feel for the direction and rate of change.  

 

The climatological norm is for the tropical Atlantic and east Pacific SSTs to rise steadily until around early September before they level off and start falling again. Various factors cause departures from the seasonal trends. This includes the ENSO state (covered in my recent tele thread post), storms and strength of winds which can (at least for a few days) mix up the surface layers and slightly reduce surface temps, cloudiness/sunshine (mostly marginal influences near the equator) and sub surface currents and cold upwellings - such as AMOC and the cold phase of the AMO which can bring some much colder waters from the deep ocean to the surface.

 

If you study and compare those SST charts above, you'll see that over just 4 days, they have risen (not a smooth trend on a daily basis) in the west but fallen in the east. The key area of 10N to 20N and, to a lesser extent, 0N to 10N show this up nicely.  So, we need to monitor these changes and if the trends continue, it's highly likely to suppress the formation, development and strength of tropical storms forming on the AEW during this season.  Malcolm's charts shows that there are now (and likely to continue for the rest of the season) plenty of disturbances coming out of west Africa but as he says, it's what happens to them as they push westwards across the ocean that is key.  They have a wide area of SSTs to cross which are well below the critical 27c level. Just a -1c SST anomaly should be enough to suppress development - but if they do not decay fully they might be reinvigorated by those higher SSTs in the Gulf of Mexico, if they reach there.  Much of the Caribbean is currently "marginal" and close to the 27c level (partly just below and partly just above). Interestingly, there is a significant disturbance showing up right now on an AEW.  NOAA expects a 70% chance of cyclone formation but then for it to decay.  Here's the latest NOAA update (0200 AM EDT Thu Jul 5 2018):

 

Satellite images indicate that the shower activity associated with a
small area of low pressure and a tropical wave located between
the Cabo Verde Islands and the Lesser Antilles remains well
organized, and a tropical depression could form at any time soon.
This disturbance is forecast to move westward or west-northwestward
at 15 to 20 mph over the tropical Atlantic Ocean. However, in a few
days, the upper-level winds are forecast to become unfavorable, and
the system is expected to degenerate into a trough of low pressure
before it approaches the Lesser Antilles.
* Formation chance through 48 hours...high...70 percent.
* Formation chance through 5 days...high...70 percent.

 

It's currently at 11N, 40W and expected to be at around 15N, 60W within 5 days.  Apart from the upper winds being less favourable for further development (referred to by NOAA) the track is over sub 27c SSTs (mostly 26c to 27c). It will be fascinating to watch this storm. The other Atlantic basin tropical disturbance developed much further north in the above average SST area near Bermuda (mostly 28c +).  We may see quite a few disturbances develop there this season but the vast majority of these are too far north and become caught up in troughs moving out of the US and merge/decay quickly (as NOAA forecast that this one is expected to do).  Meanwhile, hurricane Fabio in the east Pacific is tracking north-westwards.  The generally above average SSTs there are likely to produce a much busier than usual season (6 named storms already).  As I said previously, it's quite possible for one or two of these to make it across into the Gulf of Mexico where they will find mostly 27c+ SSTs.  

 

With the AMO going -ve and these "marginal" SSTs in the east and the higher SSTs further west, this will be a fascinating period of monitoring.  Right, back to putting more hurricane related papers in the portal.  Thursdays and Fridays are my quiet period for my business and when I have time for my "weather" activities.  David :) 

 

 

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A fascinating period of monitoring indeed David. As well as the anomalously cooler SSTs off the Africa coast to monitor, there is also a problem with upper atmospheric wind shear conditions in the Gulf and Caribbean at the moment. Normally from the end of June and into July we would be expecting to see some tropical cyclone development in this region, but wind shear conditions are currently quite hostile and it's likely that any storms trying to form would have their tops sheared off.

This is potentially looking like a persistent problem this season, with Phil Klotzbach tweeting yesterday:

 

"Latest Climate Forecast System model runs predict much stronger than normal vertical wind shear during August-October in Caribbean & a bit stronger than normal further east in tropical Atlantic. If this verifies, would likely reduce Atlantic #hurricane activity."
https://twitter.com/philklotzbach/status/1014166764618313730

 

Here's the current GFS 5-day mean forecast for 850 - 200 hPa wind shear anomaly from July 5th-10th and then (looking even worse) for July 14th-19th.

Source: https://www.tropicaltidbits.com

 

GFS Wind Shear 5-day mean 850-200hpa 5-10July.jpg

GFS Wind Shear 5-day mean 850-200hpa 14-19July.jpg

 

These conditions are more resembling what would be expected under El Nino (illustration below), so with a neutral ENSO forecast for the season I admit to being a little puzzled by the persistence of such strong wind shear. Is it down to stronger-than-normal Trade Winds? If anyone has any thoughts on this I would appreciate hearing!

 

El Nino hurricane impact.jpg

 

 

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Well this will be interesting to watch. No sooner had I posted the above, I take a look at Twitter and Accuweather have tweeted about newly formed Tropical Storm Beryl moving towards the strong wind shear. Go to the tweet (link below) to see their article and video: "Newly formed Atlantic Tropical Storm Beryl may not survive trip into Caribbean".

 

Accuweather tweet Beryl wind shear.jpg

 

https://twitter.com/breakingweather/status/1014942713370828803

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1 hour ago, Blessed Weather said:

A fascinating period of monitoring indeed David. As well as the anomalously cooler SSTs off the Africa coast to monitor, there is also a problem with upper atmospheric wind shear conditions in the Gulf and Caribbean at the moment. Normally from the end of June and into July we would be expecting to see some tropical cyclone development in this region, but wind shear conditions are currently quite hostile and it's likely that any storms trying to form would have their tops sheared off.

This is potentially looking like a persistent problem this season, with Phil Klotzbach tweeting yesterday:

 

"Latest Climate Forecast System model runs predict much stronger than normal vertical wind shear during August-October in Caribbean & a bit stronger than normal further east in tropical Atlantic. If this verifies, would likely reduce Atlantic #hurricane activity."
https://twitter.com/philklotzbach/status/1014166764618313730

 

Here's the current GFS 5-day mean forecast for 850 - 200 hPa wind shear anomaly from July 5th-10th and then (looking even worse) for July 14th-19th.

Source: https://www.tropicaltidbits.com

 

These conditions are more resembling what would be expected under El Nino (illustration below), so with a neutral ENSO forecast for the season I admit to being a little puzzled by the persistence of such strong wind shear. Is it down to stronger-than-normal Trade Winds? If anyone has any thoughts on this I would appreciate hearing!

 

SNIPPED (charts removed)

 

 

1 hour ago, Blessed Weather said:

Well this will be interesting to watch. No sooner had I posted the above, I take a look at Twitter and Accuweather have tweeted about newly formed Tropical Storm Beryl moving towards the strong wind shear. Go to the tweet (link below) to see their article and video: "Newly formed Atlantic Tropical Storm Beryl may not survive trip into Caribbean".

 

SNIPPED (charts removed)

 

 

 

Hi Malcolm, we seem to be dominating this thread - I'm surprised it's so quiet just when things are getting interesting.  Yes Beryl was correctly forecast by NOAA - it was that disturbance that I referred to in my post early this morning (UK time) which was near the Cape Verde Islands at 0200 EDT but perhaps is 12 hours or so ahead in terms of its development. They expected it to reach tropical depression and then tropical storm status over the next 48 hours (a 70 % chance given from yesterday) and then very briefly a category 1 hurricane before hitting the buffers.  NOAA stated that the upper conditions were not conducive to sustained cyclogenis and you referred to that again in your post. Let's have a look at the current position and forecast:  

ha1.PNG

 

 

BULLETIN
Tropical Storm Beryl Advisory Number   2
NWS National Hurricane Center Miami FL       AL022018
500 PM AST Thu Jul 05 2018

...TINY BERYL STRENGTHENING OVER THE TROPICAL ATLANTIC...


SUMMARY OF 500 PM AST...2100 UTC...INFORMATION
----------------------------------------------
LOCATION...10.3N 42.8W
ABOUT 1295 MI...2080 KM ESE OF THE LESSER ANTILLES
MAXIMUM SUSTAINED WINDS...50 MPH...85 KM/H
PRESENT MOVEMENT...W OR 275 DEGREES AT 16 MPH...26 KM/H
MINIMUM CENTRAL PRESSURE...1004 MB...29.65 INCHES


WATCHES AND WARNINGS
--------------------
There are no coastal watches or warnings in effect.


DISCUSSION AND OUTLOOK
----------------------
At 500 PM AST (2100 UTC), the center of Tropical Storm Beryl was
located near latitude 10.3 North, longitude 42.8 West.  Beryl is
moving toward the west near 16 mph (26 km/h).  A fast westward to
west-northwestward motion is expected through the weekend.  On the
forecast track, the center of Beryl will remain east of the Lesser
Antilles through Sunday.

Maximum sustained winds have increased to near 50 mph (85 km/h)
with higher gusts.  Additional strengthening is forecast, and Beryl
could become a hurricane by Friday or Saturday.  Beryl is forecast
to degenerate into an open trough just east of the Lesser Antilles
over the weekend.

Beryl is a tiny tropical storm.  Tropical-storm-force winds extend
outward up to 35 miles (55 km) from the center.

The estimated minimum central pressure is 1004 mb (29.65 inches).


HAZARDS AFFECTING LAND
----------------------
None


NEXT ADVISORY
-------------
Next complete advisory at 1100 PM AST.

ha2.PNG

 

I posted quite a few more papers today in the portal - all of them on the African Easterly Waves. There are a few of them that deal with wind shear and what can restrict or inhibit full cyclogenesis.  Next week, we must review a selection of these papers on the tele thread - some of them cover the current "restricted" set up from similar conditions in the past. As you requested, I'll put that excellent full paper from "Comet" in there right now. More of them to go in tomorrow.

 

 

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On 7/5/2018 at 7:47 AM, Blessed Weather said:

(SNIPPED)

 

But whilst the AEWs might be the seeds for hurricane development, as they exit Africa into the Atlantic the SSTs then play their role in 'feeding' the disturbance so it develops into a hurricane. So as you've also posted above, of great interest atm is the anomalously cool SSTs in the Atlantic and in particular the Main Development Region (MDR) for hurricanes which in large areas is 1C cooler than normal. This is now shaping up to be an important factor in subduing hurricane activity this season. Here's the latest anomaly from NOAA on June 28th and for comparison the same chart from back in January:

 

 

 

Well done Beryl! The cooler SST's off the African coast might well be seen in hindsight to have subdued hurricane activity this coming season, but Beryl wasn't put off!  :)

 

Ryan tweet Beryl cool SST 06July2018.jpg

 

https://twitter.com/RyanMaue/status/1015220484466794496

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UPDATES ON BERYL (WITH MY COMMENTS ON A RECENT RELATED VIDEO PRESENTATION) AND TROPICAL DEPRESSION 3

 

1. "Hurricane" Beryl:

hu1.PNG

000
WTNT32 KNHC 062044 CCA
TCPAT2

BULLETIN
Hurricane Beryl Advisory Number   6...Corrected
NWS National Hurricane Center Miami FL       AL022018
500 PM AST Fri Jul 06 2018

Corrected to indicate the time of intermediate advisory issuance at
800 PM AST and to remove extraneous text in the first paragraph of
the Discussion and Outlook section.

...MINIATURE BERYL SPEEDING WESTWARD OVER THE TROPICAL ATLANTIC...

SUMMARY OF 500 PM AST...2100 UTC...INFORMATION
----------------------------------------------
LOCATION...10.6N 47.8W
ABOUT 965 MI...1555 KM ESE OF THE LESSER ANTILLES
MAXIMUM SUSTAINED WINDS...80 MPH...130 KM/H
PRESENT MOVEMENT...W OR 270 DEGREES AT 15 MPH...24 KM/H
MINIMUM CENTRAL PRESSURE...994 MB...29.36 INCHES

WATCHES AND WARNINGS
--------------------
CHANGES WITH THIS ADVISORY:

The government of Barbados has issued a Hurricane Watch for
Dominica.

The government of France has issued a Tropical Storm Watch for
Martinique, Guadeloupe, St. Martin, and St. Barthelemy.

SUMMARY OF WATCHES AND WARNINGS IN EFFECT:

A Hurricane Watch is in effect for...
* Dominica

A Tropical Storm Watch is in effect for...
* Martinique
* Guadeloupe
* St. Martin
* St. Barthelemy

A Hurricane Watch means that hurricane conditions are possible
within the watch area.

A Tropical Storm Watch means that tropical storm conditions are
possible within the watch area.

Interests elsewhere in the Lesser Antilles should monitor the
progress of Beryl, as additional watches could be required for other
islands tonight or early Saturday.

DISCUSSION AND OUTLOOK
----------------------
At 500 PM AST (2100 UTC), the center of Hurricane Beryl was located
near latitude 10.6 North, longitude 47.8 West.  Beryl is moving
toward the west near 15 mph (24 km/h).  A faster westward to
west-northwestward motion is expected to begin over the weekend and
continue through early next week.  On the forecast track, the
center of Beryl will approach the Lesser Antilles over the weekend
and cross the island chain late Sunday or Monday.

Maximum sustained winds are near 80 mph (130 km/h) with higher
gusts.  Some strengthening is forecast during the next couple of
days, and Beryl could still be a hurricane when it reaches the
Lesser Antilles late Sunday or Monday.  Weakening is expected once
Beryl reaches the eastern Caribbean Sea on Monday, but the system
may not degenerate into an open trough until it reaches the vicinity
of Hispaniola and the central Caribbean Sea.

Hurricane-force winds extend outward up to 10 miles (20 km) from the
center, and tropical-storm-force winds extend outward up to 35 miles
(55 km).

The estimated minimum central pressure is 994 mb (29.36 inches).

HAZARDS AFFECTING LAND
----------------------
WIND:  Tropical storm or hurricane conditions are possible within
the watch areas by late Sunday or Monday.

NEXT ADVISORY
-------------
Next intermediate advisory at 800 PM AST.
Next complete advisory at 1100 PM AST.

$$
Forecaster Berg

My Comments:

Beryl reached hurricane status a few hours ahead of schedule. By the time it reaches the Caribbean islands it is expected to have weakened to a tropical storm.  Several warnings and watches have been issued but Beryl is an unusually small feature and, at worst, only a very small area will be impacted. As Malcolm                  (@Blessed Weather) stated in his recent post (above) Beryl managed to reach hurricane status despite travelling over sub 27c SSTs for much of her journey out of Africa.  The upper conditions should prevent Beryl from developing further and her life span will be pretty short.

 

By coincidence, I was busy adding a load more hurricane papers into the Research Portal this afternoon. Most of those I entered today are video presentations from the AMS 33rd  “Hurricanes and Tropical Meteorology” conference held at Ponte Vedra, Florida, USA between 16th and 20th April, 2018. One presentation helps to explain Beryl's unusual behaviour. That is   The Effects of Initial Vortex Size on Tropical Cyclogenesis and Intensification (click on the title for a direct link to the portal entry and summary).  From there, you'll find a link to an excellent 14 minute video presentation.  In short, very small vortices under 50 km (about 31 miles) across usually develop much faster than larger ones with their convective layers becoming organised quickly over a very narrow area.  They move more quickly (with less time to interact with the sea surface below).  NOAA describes Beryl as a "tiny feature" with hurricane force winds restricted to a radius of only 10 miles (and storm force winds out to 35 miles).  So the central vortex is even smaller than the smallest example referred to in the presentation. It may well have been this tiny size that led NOAA to underestimating the speed of development.  The good news for those few islanders who might be in Beryl's path is that these tiny features usually decay very quickly.  With the unfavourable upper conditions further suppressing its development and life span.

 

The video also covers medium and large vortices.  The larger disturbances go through the whole process much more slowly. It usually takes much longer for the convective layers to become properly organised. Moving more slowly they have longer to interact with surrounding conditions - higher SSTs (27c+) would assist its development (various other factors are involved too) and prolong its life span but lower SSTs (below 27c) would inhibit development.  Here's an interesting chart from the video:

hz.PNG

The largest ever (by area) tropical cyclone was Super Typhoon "Tip" - equivalent in size to half over the US!  Amazingly just about the whole of Beryl would have fitted into Tip's eye!  I circled Beryl in red in the satellite image below which demonstrates what a tiny feature she is. By comparison, "tropical depression 3" (circled in blue and described below) is already about 4 to 5 times the size of Beryl.

hz3.PNG

 

2. Tropical Depression 3:

hu2.PNG

000
WTNT33 KNHC 062039
TCPAT3

BULLETIN
Tropical Depression Three Advisory Number   1
NWS National Hurricane Center Miami FL       AL032018
500 PM EDT Fri Jul 06 2018

...TROPICAL DEPRESSION FORMS WELL OFF THE NORTH CAROLINA COAST...
...EXPECTED TO REMAIN OFFSHORE...


SUMMARY OF 500 PM EDT...2100 UTC...INFORMATION
----------------------------------------------
LOCATION...32.2N 73.8W
ABOUT 230 MI...370 KM SSE OF CAPE HATTERAS NORTH CAROLINA
MAXIMUM SUSTAINED WINDS...30 MPH...45 KM/H
PRESENT MOVEMENT...NNW OR 335 DEGREES AT 5 MPH...7 KM/H
MINIMUM CENTRAL PRESSURE...1016 MB...30.01 INCHES


WATCHES AND WARNINGS
--------------------
There are no coastal watches or warnings in effect.

Interests along the coast of North Carolina should monitor the
progress of this system.


DISCUSSION AND OUTLOOK
----------------------
At 500 PM EDT (2100 UTC), the center of newly formed Tropical
Depression Three was located near latitude 32.2 North, longitude
73.8 West. The depression is moving toward the north-northwest near
5 mph (7 km/h).  The depression should slow down and meander of well
offshore of the coast of North Carolina through Monday.

Maximum sustained winds are near 30 mph (45 km/h) with higher gusts.
The depression is forecast to become a tropical storm on Saturday,
with gradual strengthening expected through Monday.  A
reconnaissance plane is scheduled to investigate the cyclone on
Saturday.

The estimated minimum central pressure is 1016 mb (30.01 inches).


HAZARDS AFFECTING LAND
----------------------
None


NEXT ADVISORY
-------------
Next complete advisory at 1100 PM EDT.

$$
Forecaster Avila

My Brief Comments:

NOAA expected this feature to develop into a named tropical storm around Saturday and it too should briefly become a category 1 hurricane around next Wednesday.  Unlike Beryl, this is a larger feature and a "slow burner". The conditions are much more conducive up there with that warm patch around Bermuda and thru to the US eastern seaboard as can be seen on the latest SST chart below:

hz2.PNG

That area has SSTs of 28c to 29c.  This storm/hurricane is forecast to move slowly north and then north-east and not make landfall at all.  it will then hit much cooler waters and also merge with a frontal system/trough moving south-east out of the US - well defined in the satelitte image. So it should decay rapidly by the end of next week.

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The waters off the SE coast are very warm.

FB_IMG_1530917015813.jpg

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The waters off the nj coast are in the upper 70s.

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THE RAPID WEAKENING OF HURRICANE BERYL + A REVIEW OF ANOTHER RELATED FASCINATING RECENT VIDEO PRESENTATION

 

In my last post, I referred to an excellent video presentation looking at the size of tropical storms and hurricanes which demonstrated that those with very small vortices can often intensify and weaken much more quickly as well as move much faster than  larger storm systems. "Beryl" was a perfect example of an unusually small feature. It only became a (category 1) hurricane for a few hours having intensified rapidly.  It is back to a tropical storm now and is becoming very disorganised and expected to weaken further - back to a tropical depression with only winds gusts expected to reach storm force. It's moving quite quickly and forecast to speed up further.  It has met most of the conditions outlined for a small feature in the presentation (more below). Let's just have a quick look at the latest NOAA chart and public advisory.

hx1.PNG

000
WTNT32 KNHC 081448
TCPAT2

BULLETIN
Tropical Storm Beryl Advisory Number  13
NWS National Hurricane Center Miami FL       AL022018
1100 AM AST Sun Jul 08 2018

...BERYL MOVING QUICKLY WEST-NORTHWESTWARD TOWARD THE LESSER
ANTILLES WITH NO CHANGE IN STRENGTH...


SUMMARY OF 1100 AM AST...1500 UTC...INFORMATION
-----------------------------------------------
LOCATION...14.4N 57.9W
ABOUT 210 MI...335 KM E OF MARTINIQUE
ABOUT 235 MI...380 KM ESE OF DOMINICA
MAXIMUM SUSTAINED WINDS...45 MPH...75 KM/H
PRESENT MOVEMENT...WNW OR 290 DEGREES AT 23 MPH...37 KM/H
MINIMUM CENTRAL PRESSURE...1007 MB...29.74 INCHES


WATCHES AND WARNINGS
--------------------
CHANGES WITH THIS ADVISORY:

The Government of Barbados has discontinued the Tropical Storm
Watch for Barbados.

SUMMARY OF WATCHES AND WARNINGS IN EFFECT:

A Tropical Storm Warning is in effect for...
* Dominica
* Guadeloupe

A Tropical Storm Watch is in effect for...
* Martinique, St. Martin, and St. Barthelemy
* Saba and St. Eustatius
* St. Maarten

A Tropical Storm Warning means that tropical storm conditions are
expected somewhere within the warning area.

A Tropical Storm Watch means that tropical storm conditions are
possible within the watch area.

Interests elsewhere in the Leeward Islands, the Virgin Islands,
Puerto Rico, and the Dominican Republic should monitor the progress
of Beryl.

For storm information specific to your area, please monitor products
issued by your national meteorological service.




DISCUSSION AND OUTLOOK
----------------------
At 1100 AM AST (1500 UTC), the disorganized center of Tropical
Storm Beryl was located near latitude 14.4 North, longitude 57.9
West. Beryl is moving toward the west-northwest near 23 mph (37
km/h), and this motion with an increase in forward speed is expected
during the next couple of days.  On the forecast track, the center
of Beryl or its remnants will approach the Lesser Antilles today,
cross the island chain tonight, and move near or south of the Virgin
Islands and Puerto Rico on Monday.

Maximum sustained winds are near 45 mph (75 km/h) with higher gusts.
Gradual weakening is anticipated during the next 36 hours, and Beryl
is forecast to degenerate into a trough of low pressure as it moves
across the Lesser Antilles and into the eastern Caribbean Sea by
Monday.

Tropical-storm-force winds extend outward up to 45 miles (75 km)
from the center.

The estimated minimum central pressure is 1007 mb (29.74 inches).


HAZARDS AFFECTING LAND
----------------------
WIND:  Tropical storm conditions are expected in Dominica and
Guadeloupe tonight.  Tropical storm conditions are possible
in the watch areas of the Lesser Antilles by later today or Monday.
Strong gusty winds are also possible in the Virgin Islands and
Puerto Rico on Monday.

RAINFALL:  Beryl is expected to produce storm total rain
accumulations of 2 to 3 inches through Tuesday across the Leeward
and the Virgin Islands, as well as Puerto Rico.  Local amounts up to
5 inches are possible.


NEXT ADVISORY
-------------
Next intermediate advisory at 200 PM AST.
Next complete advisory at 500 PM AST.

$$
Forecaster Stewart

------------------------------------------------------------------------------------------------------------------------------------------------------------------------

I have been adding yet more video presentations to the Teleconnections Research Portal - all the recent ones coming from the "AMS 33rd Conference on Hurricanes and Tropical Meteorology" held at Ponte Vedra, Florida, USA between 16th and 20th April, 2018.  Today, I came across a brilliant presentation on the  Variability of Tropical Cyclone Rapid Weakening on a Global Scale  (click on the title for a direct link to the portal entry and summary).  From there, you'll find a link to the 15 minute video presentation.  In short, the presenter (Kimberly M. Wood, Mississippi State Univ., Mississippi State,  US) explains that only very few papers deal with the "rapid weakening" of some storm systems.  She says that many forecasters can be taken by surprise, leading to exaggerated advisories and warnings. So, this is almost as vital as forecasting storm intensification. She studies all global tropical cyclones over a 31 year period (1986 to 2016).  She eliminates storms making landfall and then weakening as this is already well understood.  She focuses on storms that suddenly weaken out at sea "before" they make landfall. Hurricane Beryl very much falls into this category.  She shows that "rapid weakening" is least common in the Atlantic, as can be seen in the chart below:

hx2.PNG

The deep red represents the areas in the tropical oceans where most "rapid weakening" events have occurred. The black areas are where only a few events have occurred.  The blue areas surrounded by red are islands which were removed from the study so that only ocean environments could be considered.  Note that Beryl's track along (or even south of) the southern boundary of the previously recorded area making it an even more unusual event - ie: most hurricanes moving towards the Caribbean do not weaken just before they get there.  Kimberly, then focuses on the reasons for the sudden weakening. The most usual (highlighted in the paper I reviewed in my last post) were:

 

  • Lower sea surface temperatures (Beryl made it over lower ssts for much of her journey from Africa) and was/is actually approaching slightly higher ssts).  Kimberely suggest 28c + (rather than the critical level of 27c +) for sustaining storm intensity. When tropical storms get caught up in the mid latitude circulation (as Hurricane Chris is expected to do in the middle of next week) they speed up and rapidly weaken as they move across much lower ssts.  This is even more the case in the Pacific Ocean.  This does not apply to Beryl.
  • Dry air intrusion - the upper conditions can also be very important. Cutting off the supply of moist air can quickly impact on a storm's intensity.  I have put several papers and video presentations into the Research Portal on this topic, including a couple on dry Saharan air (and dust) that can be drawn into African Easterly Waves as they move out into the Atlantic prior to their crossing. Dry air layers can occur anywhere and this is one factor affecting  Beryl (see below).
  • Wind shear -  this can alter the track of a storm but more significantly if the upper level winds are in an opposing direction to the surface layer winds this creates the shear and these opposing forces can be strong enough to literally tear a storm system to pieces.  Malcolm (@Blessed Weather) mentioned this in a post further up this page and the earlier NOAA advisories also suggested that Beryl's development and life span would be suppressed due to the non-conducive upper wind conditions.
  •  

Kimberley mentions other factors too but, hopefully, I've whetted your appetites sufficiently so that you'll watch this excellent video.   

 

Let's have a look at the precipitation and moisture charts to see what Beryl is up against:

hx3.PNG

We can see the vast area of high pressure which is pumping dry air southwards towards the Caribbean. There is only a small expanse of rainfall wrapped around Beryl and  she is sucking in more and more drier air into her system. Meanwhile Hurricane Chris has a wider area of heavier rainfall in its circulation and this is also associated with the trough that has just moved out of the US  and is moving southeast and eastwards. There is much drier air just behind that trough as well as a strong build of pressure.

hz4.PNG

This chart gives us an even better overview of the level of moisture held in the middle layers. There is a large area of dry air sitting right ahead of Beryl's path.  There is even drier air just north of Chris.

 

Overall Beryl has been an unusual hurricane. A tiny feature that grew very quickly into a category 1 hurricane and is weakening just as quickly before she makes landfall.  The upper conditions (wind shear and especially dry air intrusion) should ensure that she dissipates very quickly.  The ssts did not assist initially.  Although ssts should rise further in the western tropical Atlantic over the next few weeks, they may actually fall further in the east.  So, although we'll see a number of disturbances moving out of Africa perhaps most of them will suffer a similar fate to Beryl. 

 

Chris has formed in that well above average sst area between Bermuda and the US coast.  The conditions for further storms forming up there seem likely to remain conducive for at least the first half of the hurricane season. Very few storms that develop up there ever make landfall (it's generally those on much longer tracks that can do). Meanwhile ssts in the Gulf of Mexico and the eastern Pacific are well above the critical level.

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4 hours ago, Blessed Weather said:

A surprisingly active start to the hurricane season considering several key drivers (negative AMO, cool SSTs, and positive NAO) would suggest otherwise. So this interesting discussion on Twitter caught my eye:

 

Ventrice hurricane tweet 09July2018.jpg

 

https://twitter.com/MJVentrice/status/1016432267382722560

 

See my tweets below.  I believe the two early-season hurricanes this year do have significance regarding the outlook for the peak of the season.

 

 

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Batten down the hatches. It’s coming!

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2 hours ago, 33andrain said:

Batten down the hatches. It’s coming!

:what2:

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6 hours ago, Yaakov said:

 

See my tweets below.  I believe the two early-season hurricanes this year do have significance regarding the outlook for the peak of the season.

 

 

Excellent point Yakov. Where they develop does make a big difference for us. Hurricane Belle in AUG 1976 is a perfect example of this and that storm remains  the greatest wind/rain combo I ever saw in a Tropical System to this day. Irene in Aug 2011 is number 2. 

 

Belle formed near the Bahamas I believe. 

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1 hour ago, Bring Back 1962-63 said:

VERY MIXED SIGNALS FOR THE 2018 HURRICANE SEASON

 

This thread hasn't even reached the end of page 3 but, just reading back over the posts, we already have a huge mix of forecasts and predictions for this hurricane season.  This range of opinion extends across the community. We are blessed with some expert meteorologists on here, some keen and knowledgeable hurricane enthusiasts and a number of tweets have been posted from highly respected sources and if they cannot agree, something unusual must be going on and indeed it is.  I accept that in most years, we can find some good correlations with the prevailing conditions  in previous years - just as @Yaakov identifies two posts above this one. However, I do not believe that using previous years as analogues will really help us this year as there are far too many conflicting forces in place. Let's look at a few of these:

 

ENSO (El Nino Southern Oscillation):

NOAA's latest weekly ENSO report has just been published:

 

http://www.cpc.ncep.noaa.gov/products/analysis_monitoring/lanina/enso_evolution-status-fcsts-web.pdf

 

During the last 2 months we have finally shaken off the La Nina and moved into ENSO neutral conditions with a high chance of (fairly weak) El Nino conditions developing during the rest of this year.  I did a more comprehensive post on this about a week ago (on the Teleconnections thread but with a "plug" on here, higher up this page).  Since then, the warming trend has continued apace as can be seen on this chart:

h10.7a.PNG  

The Nino 1+2 anomaly was -1c only 2 weeks ago but is about to join the other regions in positive territory.  This was expected with warmer sub surface currents continuing to upwell. It is accepted that the Atlantic hurricane season is usually more active during La Nina episodes and less so during El Nino episodes but many other factors are involved too. With the transition from La Nina to El Nino conditions well underway, this does not really help us this season in terms of the dominant state!   

 

SSTs (Sea Surface Temperatures):

The chart below (also from the NOAA ENSO report) shows the changes in SSTs over the last 4 weeks.  Just look at that large below average area extending from equatorial Africa. It is steadily cooling and expanding.  Malcolm (@Blessed Weather) and I have made a number of references to this on this thread already (see AMO under the next heading). 

h10.7b.PNG

The majority of hurricanes and well over 80% (some recent research suggests over 90%) of major hurricanes develop on disturbances moving out of Africa and carried across the ocean on African easterly waves. I pointed out before that any disturbances tracking from west to east will have to cross a lot of ocean with SSTs below the critical point of 27c. 

h10.7.PNG

NOAA have just updated their "Reynolds" weekly anomaly SST charts. Just look at the cooling trend continuing during the last week. Meanwhile the warmer areas to the north and west continue to warm.  This leaves us with these current values:

h10.7c.PNG

So, although we have a "cool" SST source region for the development of "long-track" tropical disturbances we have warm SST conditions over most of the Caribbean (they have risen there during the last couple of weeks), the Gulf of Mexico and in the Atlantic centred around Bermuda and extending to the US east coast as well as northwards. The two recent hurricanes have illustrated this perfectly and I went into this in my two previous posts on here. Beryl did manage to form as it crossed on an African easterly wave but was an extremely unusual and tiny feature. I showed a paper on vortex sizes and how very small ones can develop, intensify and decay very quickly and this is exactly what Beryl did. NOAA have just issued a new advisory on Beryl's remnants:   

ZCZC MIATWOAT ALL TTAA00 KNHC DDHHMM Tropical Weather Outlook NWS National Hurricane Center Miami FL 800 AM EDT Tue Jul 10 2018 For the North Atlantic...Caribbean Sea and the Gulf of Mexico: The National Hurricane Center is issuing advisories on Tropical Storm Chris, located a couple of hundred miles south-southeast of the North Carolina Outer Banks. 1. The remnants of Beryl are producing gusty winds and areas of heavy rain over portions of central and eastern Hispaniola, and the adjacent Atlantic and Caribbean waters. This system is expected to move west-northwestward across the rest of Hispaniola today and over the southeastern Bahamas this evening. Little development is expected during the next day or so due to land interaction and unfavorable upper-level winds. The disturbance is forecast to turn northward over the western Atlantic on Wednesday where upper-level winds could become a little more conducive for the regeneration of a tropical cyclone later this week. Regardless of development, locally heavy rains and gusty winds are likely over portions of Hispaniola and the Bahamas as the remnants of Beryl move through those areas. Additional information on this system can be found in High Seas Forecasts issued by the National Weather Service. * Formation chance through 48 hours...low...20 percent. * Formation chance through 5 days...medium...50 percent."

 

Although the tropical storm has dissipated, there is some residual energy and moisture  in the eastern Caribbean.  As this tracks north it enters more conducive conditions (more especially after 5 days).  If a new tropical storm or hurricane is born out of these remnants, I wonder if it should be given a new name?  After all, this is not a case of a hurricane weakening and re-strengthening - Beryl completely lost her mojo!  What a fascinating and highly unusual situation!  

 

Then, moving onto Hurricane Chris: 

"512 WTNT33 KNHC 101452 TCPAT3 BULLETIN Tropical Storm Chris Advisory Number 16 NWS National Hurricane Center Miami FL AL032018 1100 AM EDT Tue Jul 10 2018 ...CHRIS FINALLY MOVING NORTHEASTWARD AWAY FROM THE UNITED STATES... ...EXPECTED TO BECOME A HURRICANE LATER TODAY... SUMMARY OF 1100 AM EDT...1500 UTC...INFORMATION ----------------------------------------------- LOCATION...33.1N 73.1W ABOUT 200 MI...320 KM SE OF CAPE HATTERAS NORTH CAROLINA MAXIMUM SUSTAINED WINDS...70 MPH...110 KM/H PRESENT MOVEMENT...NE OR 50 DEGREES AT 9 MPH...15 KM/H MINIMUM CENTRAL PRESSURE...993 MB...29.33 INCHES WATCHES AND WARNINGS -------------------- There are no coastal watches or warnings in effect. Interests along the coast of North Carolina and in Atlantic Canada should monitor the progress of this system. DISCUSSION AND OUTLOOK ---------------------- At 1100 AM EDT (1500 UTC), the center of Tropical Storm Chris was located near latitude 33.1 North, longitude 73.1 West. Chris is moving toward the northeast near 9 mph (15 km/h), and this motion is expected to continue today. A faster northeastward motion is expected to begin tonight and continue into Thursday. Maximum sustained winds are near 70 mph (110 km/h) with higher gusts. Chris is forecast to strengthen into a hurricane later today when it moves over warmer waters, and some additional strengthening is expected through Wednesday night. Chris is forecast to become a strong post-tropical cyclone by Thursday night or early Friday. Tropical-storm-force winds extend outward up to 70 miles (110 km) from the center. The estimated minimum central pressure is 993 mb (29.33 inches). HAZARDS AFFECTING LAND ---------------------- SURF: Swells generated by Chris are expected to increase and affect portions of the coasts of North Carolina and the mid-Atlantic states during the next few days. These swells could cause life-threatening surf and rip current conditions. Please consult products from your local weather office."

Chris is just strengthening to a hurricane right now.  As NOAA correctly predicted, he is now speeding up and moving north-east and seems very unlikely to make landfall. In 2 to 3 days Chris will hit those much lower SSTs and weaken considerably.  He's now destined to cross the Atlantic and seems to be heading for the UK (probably over or to our north) as a moderate Atlantic storm. As I said recently, the very warm pool off the US south-eastern/eastern coast is likely to produce a number of storms and some of these may reach tropical storm or even cat 1 hurricanes.  Unless they manage to hang around for a long time, the vast majority will not make landfall. It is the long track storms moving into the Caribbean, the Gulf of Mexico  or just east of Florida, that "can" sometimes develop into major hurricanes.  

 

I also mentioned that there is likely to be plenty of activity in the tropical eastern Pacific.  The charts below show the current position:

 h10.7d.PNG

There is a a large east to west pool of 27c + SSTs.

h10.7e.PNG

During the last week, the 7 day anomalies have risen slightly over a wide area.  Depending on other factors, upper conditions, winds and wind shear and moisture levels, I would expect to see many more named storms forming in this area. So far this season, we have already seen 7 (8) storms. One tropical depression and six named storms, two of which became hurricanes.  Yes I put 8 in brackets as in the last couple of hours NOAA show another disturbance (not predicted earlier) with a small chance of cyclone development:

"ZCZC MIATWOEP ALL TTAA00 KNHC DDHHMM Tropical Weather Outlook NWS National Hurricane Center Miami FL 500 AM PDT Tue Jul 10 2018 For the eastern North Pacific...east of 140 degrees west longitude: 1. A broad area of low pressure has developed a little over 1000 miles southwest of the southern tip of the Baja California peninsula. Environmental conditions appear conducive for gradual development during the next few days as the system moves west-northwestward at about 10 mph. * Formation chance through 48 hours...low...10 percent * Formation chance through 5 days...low...20 percent".

Like the others, if this feature does develop, it is likely to stay well off-shore. The majority of east Pacific storms do but in an active season (in that region) like this one, one or two of them might move north-east and can cross central America into the Gulf of Mexico where they could easily develop into major hurricanes (I put several papers on that in the Research Portal - which I'll review on here if/when one is forecast to do just that). Let's not forgot that some of these east Pacific hurricanes can make landfall on the US west coast, especially California.  I put an excellent very recent video presentation into the portal on Hurricane Patricia - the largest hurricane on record and which rather surprised the forecasters:  Here's a link to the abstract (click on the title): The Extreme Intensification and Predictability of 2015's Hurricane Patricia - Presentation  - from there, you'll find a link to the fascinating 16 minute video. 

  

Atlantic Multidecadal Oscillation (AMO) and Atlantic Multidecadal Variability (AMV):

I'm running out of time now. Malcolm, I and several other members, mentioned on here that we're moving in a negative phase of the AMO (also known as the AMV).  Some cold currents from the deep tropical Atlantic basin are upwelling to the surface. The well below average SSTs off the African coast are now expanding steadily and it does look like this is the beginning of the transitions to many years of this anomaly.  This cycle is thought to be a totally natural one.  I will review several AMO papers on here (and/or the Teleconnections thread) in due course.  In the meantime, here's an excellent "learner's guide" that's in the portal:  About the Atlantic Multidecadal Oscillation (AMO) - A Guide  (again click on the title for a direct link to the portal entry and my review + a link to the full NOAA guide).

 

Other Signals:

Most of what I have covered so far has been related to surface conditions but the upper conditions are just as, if not more, important.  In my last post, I dealt with "dry air intrusion" and touched on "wind shear" and when NOAA state that upper conditions are or are not conducive to cyclone development these are two important factors. The precipitation and moisture charts that I posted have only changed very slightly in the last couple of days, so I won't post them again now. Looking ahead, the very large block of high pressure extending southwestwards from western Europe, through The Azores towards the east Caribbean, may shift slightly during the next week or so.  The long fetch north-easterlies "may" be interrupted and more moisture could get into the air stream. The sub tropical high pressure is, of course a quasi permanent feature  with the north-east trades on its southern flank but such long-fetch  flows are not so common.  The Azores high pressure  may take up it's more usual position and more high pressure may develop over eastern Europe in due course. This is partly due to the current rise in AAM (atmospheric angular momentum) and the changes in seasonal wave lengths but I'm going rather beyond my pay grade now!

 

How all these variables will interact is far from clear.  The season so far has already seen some surprises and Beryl was (and perhaps still is) so unusual that I'm sure we shall see several papers devoted towards her life cycle in due course.  So Geoff's  (@33andrain) "Batten Down the Hatches, it's coming" comment may or may not prove to be a fair warning ? Whatever happens, this will be a fascinating season.   David :) 

   

The SSTs in the Western Atlantic are once again well above normal with areas off of the Long Island NY beaches already over 80 degrees. If a hurricane were to develop off of the SE coast and be able to feed off of those warm waters, there would be a Major Hurricane that could threaten the Mid Atlantic and NE coastlines. Obviously many factors would have to come together to make this happen, but it is always a possibility. Just some food for thought?

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1 hour ago, Andrew Maddis said:

The SSTs in the Western Atlantic are once again well above normal with areas off of the Long Island NY beaches already over 80 degrees. If a hurricane were to develop off of the SE coast and be able to feed off of those warm waters, there would be a Major Hurricane that could threaten the Mid Atlantic and NE coastlines. Obviously many factors would have to come together to make this happen, but it is always a possibility. Just some food for thought?

 

The interesting thing that I have found in my research, is that significant (cat 2+) Long Island/New England hurricanes have only occurred in hurricane seasons with near to below normal activity.  These include 1869, 1938, 1944, 1954 (Carol, Edna), 1960 (Donna), 1985 (Gloria), 1991 (Bob).

 

Another important aspect is that the Jun water temperatures in those years featured slightly below normal SSTs in the eastern/central tropical Atlantic, and above normal SSTs off the US East Coast.  The Aug/Sep water temperatures were similar, but the above normal SSTs off the East Coast were weaker.  See attached SST composites.

 

Furthermore, I created an index of SST in the subtropical western Atlantic (from 22.5 to 42.5N and 80 to 50W):
https://www.esrl.noaa.gov/psd/cgi-bin/data/timeseries/timeseries.pl?ntype=4&lat1=23&lat2=42.5&lon1=280&lon2=310&iseas=0&mon1=4&mon2=5&iarea=0&typeout=1&Submit=Create+Timeseries

 

In this region, the SST anomaly this May/Jun is the third highest since 1948, behind only 2016 and 2012.  Warm SSTs in the subtropical western Atlantic in May/Jun, and even more so in Aug/Sep/Oct, are correlated with increased hurricane strikes along the east coast from GA northward to New England.  This is shown in the chart below, which I annotated the names of east coast hurricanes.

 

 

 

 

W Atl subtropical May-Jun SST anom trend - with E US hurricanes.jpg

NE US hurr composite SST - Sep.png

NE US hurr composite SST - Jun.png

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