December 17, 2019 -- Snow/Ice Storm Discussion/Obs - Page 38 - Archived Storm Threads - 33andrain Weather Discussion Community Jump to content
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December 17, 2019 -- Snow/Ice Storm Discussion/Obs

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Both the 12Z NAM and RGEM/RDPS moved the heavy freezing rain amounts about 10-15 miles NW along the 95 corridor.  They both had the Edison area at 0.5" or more of ZR at 6Z and now we're at around 0.1" of ZR (similar decreases from TTN to NYC).  Both models have a very steep gradient from no ZR to >0.5" ZR over maybe a 15-20 mile distance from SE to NW, so maybe this is just model "noise" but if it's real, it certainly would have a huge impact in the immediate 95 corridor.  Such a close call by those models.  I tend to believe the Euro more, with limited ZR along/near 95 and significant icing limited to 15-20 miles NW of the Turnpike and points NW of there, just based on past history with SWFE's along the coastal plain up through the 95 corridor.  There have been many times I've had ZR predictions of 1/4" or more only to see little to no ZR - that's why 1994 stands out so well.  

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considering the depth of the warm tongue and marginal Surface temps for some of the areas being discussed with modeled heavier freezing rain, id expect the NWS is anticipating the totals to be overdone... remember, similar to snow... .10" liquid isn't always giving you 1" of snow... yet models calculate as such... .10" of freezing rain, isn't necessarily giving .10" ice accretion, "ice ratios" simply put are a factor here... personally, i'm taking half to 1/4 off the modeled totals in my forecasts for this storm... it's not a warm tongue and 23 and the surface 

F079E609-7F25-4AAB-B875-28E82F1EAE00.png

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2 minutes ago, ru848789 said:

Both the 12Z NAM and RGEM/RDPS moved the heavy freezing rain amounts about 10-15 miles NW along the 95 corridor.  They both had the Edison area at 0.5" or more of ZR at 6Z and now we're at around 0.1" of ZR (similar decreases from TTN to NYC).  Both models have a very steep gradient from no ZR to >0.5" ZR over maybe a 15-20 mile distance from SE to NW, so maybe this is just model "noise" but if it's real, it certainly would have a huge impact in the immediate 95 corridor.  Such a close call by those models.  I tend to believe the Euro more, with limited ZR along/near 95 and significant icing limited to 15-20 miles NW of the Turnpike and points NW of there, just based on past history with SWFE's along the coastal plain up through the 95 corridor.  There have been many times I've had ZR predictions of 1/4" or more only to see little to no ZR - that's why 1994 stands out so well.  

Huh? the Canadian products are concerning. Are we looking at the same product.  Also the actions of upton could be considered gross negligence.  

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1 minute ago, donsutherland1 said:

The latest guidance suggests the potential for significant freezing rain not too far north and west of New York City. Based on the latest guidance, it is likely that an area stretching from West Milford, NJ across White Plains and to Danbury could pick up 0.10" to 0.25" freezing rain with the potential for more, especially in northwestern New Jersey.

 

Some of the local media outlets (radio forecasts I heard coming into work this morning) are downplaying the freezing rain risk (the specific mention concerned not more than a few hundredths of an inch). However, those outlets may be using dated guidance and/or relying on the much warmer GFS to reach a conclusion that understates risk of icing. The 3 km NAM, 12 km NAM, and RGEM are very aggressive, both with amounts and the southern extent of the freezing rain.

Are people in areas without a WWA even expecting ice tonight?

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3 minutes ago, DFridman29 said:

Are people in areas without a WWA even expecting ice tonight?

I'm not sure. Certainly some of the radio stations I heard seem to be oblivious to the risk.

 

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5 minutes ago, BMC10 said:

Huh? the Canadian products are concerning. Are we looking at the same product.  Also the actions of upton could be considered gross negligence.  

I don't get your point.  I was talking about the NAM and RGEM, which moved the heavy ZR line NW about 10-15 miles, not the GDPS (global Canadian), which still has near or over 0.5" of ZR from TTN to NYC (with a maximum of over 1" in Edison.  At this range I trust the regional, high-res mesoscale models a bit more, so I was discussing just them.  The difference between them is actually fairly small in the grand scheme (maybe a 10-15 mile move of the heaviest ZR to the NW of the NJTPK), so yes, they're all concerning.  

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I hate to say this but I've never felt more relieved to be north of 84 in one of these situations than I do now. We might get a sleet fest with the snow but that's more preferable to over .25" ice.

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3 minutes ago, ru848789 said:

I don't get your point.  I was talking about the NAM and RGEM, which moved the heavy ZR line NW about 10-15 miles, not the GDPS (global Canadian), which still has near or over 0.5" of ZR from TTN to NYC (with a maximum of over 1" in Edison.  At this range I trust the regional, high-res mesoscale models a bit more, so I was discussing just them.  The difference between them is actually fairly small in the grand scheme (maybe a 10-15 mile move of the heaviest ZR to the NW of the NJTPK), so yes, they're all concerning.  

Maybe I missed that on the rgem.  Looked bad.  My apologies.  

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Well lookie here...

 

URGENT - WINTER WEATHER MESSAGE
National Weather Service New York NY
1233 PM EST Mon Dec 16 2019

CTZ009>012-NJZ004-104>108-NYZ071-170900-
/O.EXB.KOKX.WW.Y.0015.191217T0200Z-191217T1500Z/
Southern Fairfield-Southern New Haven-Southern Middlesex-
Southern New London-Eastern Passaic-Eastern Bergen-Western Essex-
Eastern Essex-Western Union-Eastern Union-Southern Westchester-
1233 PM EST Mon Dec 16 2019

...WINTER WEATHER ADVISORY IN EFFECT FROM 9 PM THIS EVENING TO
10 AM EST TUESDAY...

* WHAT...Mixed precipitation expected. Total snow accumulations of
  up to two inches and ice accumulations up to a tenth of an inch.

* WHERE...Portions of northeast New Jersey, southern Connecticut
  and southeast New York.

* WHEN...From 9 PM this evening to 10 AM EST Tuesday.

* IMPACTS...Plan on slippery road conditions. The hazardous
  conditions could impact the Tuesday morning commute.


PRECAUTIONARY/PREPAREDNESS ACTIONS...

Slow down and use caution while traveling.

Check local Department of Transportation information services for
the latest road conditions.

&&

$$

CTZ005>008-NJZ002-103-NYZ067>070-170900-
/O.EXT.KOKX.WW.Y.0015.191217T0200Z-191217T2300Z/
Northern Fairfield-Northern New Haven-Northern Middlesex-
Northern New London-Western Passaic-Western Bergen-Orange-Putnam-
Rockland-Northern Westchester-
1233 PM EST Mon Dec 16 2019

...WINTER WEATHER ADVISORY NOW IN EFFECT FROM 9 PM THIS EVENING
TO 6 PM EST TUESDAY...

* WHAT...Mixed precipitation expected. Total snow accumulations
  of up to two inches and ice accumulations of up to around two
  tenths of an inch.

* WHERE...Portions of northeast New Jersey, southern Connecticut
  and southeast New York.

* WHEN...From 9 PM this evening to 6 PM EST Tuesday.

* IMPACTS...Plan on slippery road conditions. The hazardous
  conditions could impact the Tuesday morning and evening
  commutes.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Slow down and use caution while traveling.

Check local Department of Transportation information services for
the latest road conditions.

&&

$$
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10 minutes ago, donsutherland1 said:

The latest guidance suggests the potential for significant freezing rain not too far north and west of New York City. Based on the latest guidance, it is likely that an area stretching from West Milford, NJ across White Plains and to Danbury could pick up 0.10" to 0.25" freezing rain with the potential for more, especially in northwestern New Jersey.

 

Some of the local media outlets (radio forecasts I heard coming into work this morning) are downplaying the freezing rain risk (the specific mention concerned not more than a few hundredths of an inch). However, those outlets may be using dated guidance and/or relying on the much warmer GFS to reach a conclusion that understates risk of icing. The 3 km NAM, 12 km NAM, and RGEM are very aggressive, both with amounts and the southern extent of the freezing rain.

 

Thanks for the voice of reason, Don. News 12 this morning was relying exclusively on the GFS, based on their forecast.

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