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Yaakov

Meteorologist
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Yaakov last won the day on June 11

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About Yaakov

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    Jerusalem, Israel

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  1. Yaakov

    October 2018 Discussion & Observations

    Both GFS and Euro are forecasting highly anomalous blocking southeast of Greenland around day 8, but the Euro is showing the above normal heights associated with the block slowly retrograding toward the Davis Strait by day 10, allowing the polar jet to dive way south from the Arctic regions of Canada toward ME/Nova Scotia and locking in near-record cold air over the northeast US. The Euro progression seems to hint at the idea of two separate storms, and shows that the second potential storm would have significant input of energy from the remnants of a recurving E Pacific hurricane that ends up in the lower MS Valley by day 10. Meanwhile the GFS weakens the block and shunts it east toward Iceland, while popping another highly anomalous ridge across central-eastern Canada day 10-12.
  2. Yaakov

    2018 Atlantic Hurricane Season

    I post this FV3 run only for entertainment, but it illustrates the potential this pattern has. The signal in the ECMWF ensembles for a potentially significant hybrid East Coast storm last week of Oct is getting stronger:
  3. Yaakov

    ***Winter Countdown Thread 2018-2019***

    @Tamara, Excellent and very informative post! Thank you.
  4. Yaakov

    2018 Atlantic Hurricane Season

    And a resurgence of that same blockiness, but shifted further west into the NW Atl, combined with the typical short wavelength pattern for this time of year leading to cutoff lows traversing the central/eastern US, is what could make things very interesting along the East Coast come last week of Oct. Seeing some hints of possible tropical/subtropical cyclogenesis in that timeframe in the eastern/central Gulf of Mexico or off the SE US coast, then heading N/NE. However, even if nothing tropical forms the pattern is ripe with baroclinicity just off the East Coast.
  5. Yaakov

    2018 Atlantic Hurricane Season

    The basin-scale HWRF is also worth a look: http://storm.aoml.noaa.gov/basin/?projectName=BASIN It also has the system intensifying rapidly in the 24-36 hours before landfall.
  6. Yaakov

    7/21-7/22 Coastal Special

    Also, based on the NAM 850 mb wind forecasts, there probably should be wind advisories out for portions of eastern/central NY, western MA and VT, especially the higher terrain where it will be easier to mix down the strong winds aloft.
  7. Yaakov

    7/21-7/22 Coastal Special

    The gust forecasts from NWS Upton and Mount Holly seem too low to me. I think there will be several reports of 50+ mph gusts. Should be a wind advisory out from Jersey shore to LI.
  8. Yaakov

    2018 Atlantic Hurricane Season

    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.
  9. Yaakov

    2018 Atlantic Hurricane Season

    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.
  10. A few places in interior ME went at or just below freezing late last week: Presque Isle, ME had the latest <32F temperature in nearly 80 years. Berlin, NH had a very late freeze as well: https://twitter.com/NWSGray/status/1006521306194632704 Portions of Newfoundland are seeing accumulating snow (!) today. This is their third snowfall this month. https://twitter.com/rcbstormpost/status/1011564250735742977
  11. The significant rains remained south and west of NYC. Radar estimates in western LI, NYC and N NJ were way too high as it took a long time to saturate. Severe flash flooding occurred in parts of se PA and s. NJ with a west to east band of thunderstorms which kept training over the same areas.
  12. The significant northward trend in the 12 km NAM and other models such as UKMET makes me think that potential for locally heavy downpours today and tonight as far north as northernmost NJ, NYC and western LI has increased significantly. The RAP is fairly similar to the 12 km NAM.
  13. Potential for flooding in northern mid-Atlantic and possibly extending into NYC area and New England as well, with a slow-moving inverted trough and bowling ball upper low dropping in behind the lead shortwave. It looks like two separate rain events that together may last from Sun through much of next week. Blocky pattern with well above normal heights Greenland to central Canada forces the shortwaves underneath to slow down. Meanwhile the strong upper low off SE Canada may bring another unseasonable snow event (!) Sun-Mon to parts of Newfoundland (after the record May snow event in Gander last week). Average Jun snowfall in Gander is 4 cm but I think that is skewed by a few snowier years.
  14. Yaakov

    2018 Atlantic Hurricane Season

    My assessment of the upper pattern in the 6-10 day period is that the northern jet is displaced north of usual, with a blocking ridge centered near the Northern Plains and another anomalously strong ridge between the SE US coast and Bermuda. This creates a very weak steering flow, and does favor whatever tropical system that forms in the Gulf moving very slowly or even stalling. The slow westerly drift near LA shown by the European operational run (supported by a decent number of ens members) would be a near worst-case scenario for New Orleans area in terms of heavy rainfall/freshwater flooding, with higher tides due to persistent S winds also preventing rainwater from draining back into the Gulf. It shows locally heavier showers beginning the middle of this week in southern LA. Widespread heavy rains associated with the developing TC arrive by Fri, and continue daily through the middle of next week! See attached loop of ECMWF 24 hour rainfall. Op ECMWF shows widespread 8"+ amounts from the FL Panhandle through coastal AL/MS and into much of central/southern LA and even extreme east TX, with local amounts up to 20"! Of course this is only one scenario, but all models have been trending toward a stronger W Atl ridge, which along with the retrograding cutoff low in the N. Gulf, supports the potential for a TC to track as far west as the central/western Gulf. It would be nearly unprecedented for a tropical cyclone to directly impact LA or TX this early in the season. The only one since 1850 that hit before Jun 10 was TS Arlene in 1959 (it hit LA at the end of May). Hurricanes hit TX in mid-Jun in 1886, 1888 and 1921 and LA in 1934. Most May-early Jun TCs coming from the Caribbean or Gulf track northward toward FL or turn NE toward Cuba and the Bahamas.
  15. Yaakov

    2018 Atlantic Hurricane Season

    I agree with everything you wrote. There are several factors that do favor higher than climo chances of TC formation in the W. Caribbean from about May 20 onward til the end of the month. First is the persistent westerly wind anomalies around 10N latitude extending from the eastern Pacific into the sw Caribbean. This along with anomalous easterlies around the stronger than normal SW Atlantic high increases low-level convergence in the W. Caribbean. Also the 200 mb anticyclone is forecast to lift well north of its climatological position for this time of year, reaching the nw Caribbean by around day 9-10. This trend, along with an anomalous north-south trough extending from the central GOM toward the Yucatan, would strongly reduce shear in the w. Caribbean. Finally, the band of above normal heights extending from the Great Lakes to near/north of Bermuda teleconnects to lowering heights/pressures to the south.
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