earthlight Posted December 21, 2012 Share Posted December 21, 2012 It's snow away from the coast. BL is probably warm along the shore. But many areas have a white christmas (as in snow falling) on this run Link to comment Share on other sites More sharing options...
Allsnow Posted December 21, 2012 Share Posted December 21, 2012 ag3 knows his weather. Thanks for your analysis. The surface depicts what he is saying. But why is that sounding so warm? Link to comment Share on other sites More sharing options...
ag3 Posted December 21, 2012 Share Posted December 21, 2012 Look at soundings Mohawk posted...not a snow sounding I see .9 degrees when the precip starts for NYC. That is 33 degrees. 850's come down as the precip is falling. I am not going to worry that at 12z and 18z, the euro has temps of 35-40 degrees. Link to comment Share on other sites More sharing options...
ag3 Posted December 21, 2012 Share Posted December 21, 2012 The surface depicts what he is saying. But why is that sounding so warm? Its 33 degrees at the start of the precip. That is not warm. I dont care what the euro shows at 12z or 18z. A lot of the precip has fallen by 12z and 850's get lower as precip is falling. Link to comment Share on other sites More sharing options...
Allsnow Posted December 21, 2012 Share Posted December 21, 2012 I see .9 degrees when the precip starts for NYC. That is 33 degrees. 850's come down as the precip is falling. I am not going to worry that at 12z and 18z, the euro has temps of 35-40 degrees. I agree with what you are saying. Link to comment Share on other sites More sharing options...
ag3 Posted December 21, 2012 Share Posted December 21, 2012 Mohawk, can you run a sounding for KLGA? Just curious to see if the soundings match the wunderground surface maps at hour 87 or 3z. Wunderground shows KLGA at or below freezing at the surface, while parts of NYC are above freezing. Link to comment Share on other sites More sharing options...
ag3 Posted December 21, 2012 Share Posted December 21, 2012 I agree with what you are saying. And if you look on wunderground which shows in between hours, it has weird warm tongues of surface warmth. KLGA is at or below 32 degrees at hour 87 (when heaviest precip is falling), while other parts of NYC are above 32. Example..Here is hour 87 (while the precip is falling). The darker blue is 32 degrees or below: Link to comment Share on other sites More sharing options...
wolfie09 Posted December 21, 2012 Share Posted December 21, 2012 Mohawk, can you run a sounding for KLGA? Just curious to see if the soundings match the wunderground surface maps at hour 87 or 3z. Wunderground shows KLGA at or below freezing at the surface, while parts of NYC are above freezing. Only can do every 6 hr on the text product, maybe temps drop then rise quickly at the end of the 6 hrs...The text product from accu pro tends to be pretty good, so i'm not sure why the difference.. TUE 00Z 25-DEC 1.3 0.3 1018 68 27 0.00 554 539 TUE 06Z 25-DEC 3.9 -1.5 1013 90 96 0.17 550 540 TUE 12Z 25-DEC 4.7 -0.3 1010 94 40 0.17 548 540 Link to comment Share on other sites More sharing options...
WeatherFox Posted December 21, 2012 Author Share Posted December 21, 2012 At KNYC The 12z GFS shows the 850mb column below freezing and surface temps in the mid 30's during this potential light snow period, which is modeled to occur when it is mostly night. I agree with earthlight for a period of falling snow in NYC and the coast which melts on contact except for on grassy areas, car tops and colder surfaces as per this one run and one model. Link to comment Share on other sites More sharing options...
eduggs Posted December 21, 2012 Share Posted December 21, 2012 Agreed with the others above. Guidance looks relatively cold with low thicknesses and marginal temps along the coast and LI. That's probably falling snow with a few inches north and west trending to slush further south. Interestingly the GGEM has moved toward a more significant s/w and coastal low. If that trend catches on, we could be looking at a more significant storm. Right now the timing looks perfect for a light accumulation, esp just outside the City. Link to comment Share on other sites More sharing options...
Snow_Miser Posted December 21, 2012 Share Posted December 21, 2012 The ECMWF Snow maps on Accuweather Pro have around 3 inches of snow for I-95 N and W. Looks like about an inch of snow for the city. Very nice run for areas just inland. Link to comment Share on other sites More sharing options...
TWCCraig Posted December 21, 2012 Share Posted December 21, 2012 I ripped this from the 16-day 12z GFS forecast for KISP. Link to comment Share on other sites More sharing options...
isnice Posted December 21, 2012 Share Posted December 21, 2012 The ECMWF Snow maps on Accuweather Pro have around 3 inches of snow for I-95 N and W. Looks like about an inch of snow for the city. Very nice run for areas just inland. GFS surface parameters KSMQ. http://68.226.77.253/text/1DegGFS/GFS_KSMQ.txt Link to comment Share on other sites More sharing options...
MJO812 Posted December 21, 2012 Share Posted December 21, 2012 JMA looks good http://grib2.com/jma/CONUS_JMA_1000-500_SLPTHKPRP_96HR.gif Link to comment Share on other sites More sharing options...
Edge Weather Posted December 21, 2012 Share Posted December 21, 2012 Euro ensemble mean shows at least .15 throughout our area for the Christmas Eve into Christmas morning storm. Link to comment Share on other sites More sharing options...
patrick05 Posted December 21, 2012 Share Posted December 21, 2012 OKX now shows snow for mon eve to xmas day for my area... Link to comment Share on other sites More sharing options...
WeatherFox Posted December 21, 2012 Author Share Posted December 21, 2012 OKX now shows snow for mon eve to xmas day for my area... HPC Day 4 surface prog shows the potential with the placement of the 1012 mb low east of central NJ and south of LI. NYC on the cold conveyor belt side of the weak low which has shown model to model consistency & a slight increase in the moisture parameter. Link to comment Share on other sites More sharing options...
eduggs Posted December 21, 2012 Share Posted December 21, 2012 JMA looks good http://grib2.com/jma...THKPRP_96HR.gif The JMA doesn't look all that different than the GFS, except in QPF, where the JMA is wetter. But that is not the most reliable parameter in general, and of the JMA in particular. The Euro slides the mid level s/w through the Lakes and NYS further north than most of the other models. The GGEM is the strongest and furthest south. It really wraps up the mid levels! http://www.weatheroffice.gc.ca/data/model_forecast/234_100.gif If this sort of solution is correct, we could be looking at more of a moderate snowstorm, especially just inland. However, in light of the disagreement with other guidance and discontinuity with its previous runs, I think the 12z GGEM is too wrapped up. The GFS and UKMET are something of a compromise in terms of strength and position of the s/w. Interestingly, all of these models produce a few inches of accumulating snow just inland, which increases confidence for xmas snow. The GFS, GGEM, and Euro ensembles all basically support their operational runs, with the GFS the furthest south with the surface feature. Thicknesses are low in advance of this storm and we should be dealing with a seasonably cold airmass, so I think this will lean towards snow in the marginal cases. And the GGEM idea of a stronger system shouldn't be completely discounted. Really nice timing for snow if it happens! Link to comment Share on other sites More sharing options...
Allsnow Posted December 21, 2012 Share Posted December 21, 2012 18z gfs def more amp up with xmass event through 72hr Link to comment Share on other sites More sharing options...
Allsnow Posted December 21, 2012 Share Posted December 21, 2012 Hr 78 light snow into area. Christmas Eve night Hr 81 light snow for area Hr 84 still snowing Hr 87 still snowing 850's below entire time and surface rides 95 Link to comment Share on other sites More sharing options...
CooL Posted December 21, 2012 Share Posted December 21, 2012 What a really nice run. Light - Moderate snow on xmas morning. Probably 1-3" Link to comment Share on other sites More sharing options...
Allsnow Posted December 21, 2012 Share Posted December 21, 2012 Close to .50 this run Link to comment Share on other sites More sharing options...
CooL Posted December 21, 2012 Share Posted December 21, 2012 Close to .50 this run Actually on second look this is probably atleast 2-4" Link to comment Share on other sites More sharing options...
SnoSki14 Posted December 21, 2012 Share Posted December 21, 2012 What a really nice run. Light - Moderate snow on xmas morning. Probably 1-3" Probably more like 3-6", best run from the gfs yet on this storm. Link to comment Share on other sites More sharing options...
patrick05 Posted December 21, 2012 Share Posted December 21, 2012 Wow will LI see accumulations as well?? Hopefully so especially as it is falling in the evening/early morning Link to comment Share on other sites More sharing options...
eduggs Posted December 21, 2012 Share Posted December 21, 2012 The 18z GFS just took a step towards the GGEM in terms of its mid level evolution. The s/w is further south and has a larger amplitute than its previous runs (and moreso than most other guidance). It's not nearly as wrapped up as the 12z GGEM, but a significant change from its previous runs. If this type of solution is right, it could be a snowy xmas morning around the tristate. Link to comment Share on other sites More sharing options...
Allsnow Posted December 21, 2012 Share Posted December 21, 2012 The 18z GFS just took a step towards the GGEM in terms of its mid level evolution. The s/w is further south and has a larger amplitute than its previous runs (and moreso than most other guidance). It's not nearly as wrapped up as the 12z GGEM, but a significant change from its previous runs. If this type of solution is right, it could be a snowy xmas morning around the tristate. I'm glad you are back to posting in this forum Link to comment Share on other sites More sharing options...
Snow_Miser Posted December 21, 2012 Share Posted December 21, 2012 This run is probably about 3-5" of snow verbatim for the suburbs. Very cold and nice run. About 0.5" of precipitation falls on this run with this system on the 18z GFS from SE PA to C NJ. Very wet run. Link to comment Share on other sites More sharing options...
isnice Posted December 21, 2012 Share Posted December 21, 2012 The 18z GFS just took a step towards the GGEM in terms of its mid level evolution. The s/w is further south and has a larger amplitute than its previous runs (and moreso than most other guidance). It's not nearly as wrapped up as the 12z GGEM, but a significant change from its previous runs. If this type of solution is right, it could be a snowy xmas morning around the tristate. This is exactly that gut feeling I was talking about 3 days ago... Link to comment Share on other sites More sharing options...
Snow_Miser Posted December 21, 2012 Share Posted December 21, 2012 Looks like the Weatherbell snow maps have close to three inches of snow for most of NJ. Jackpot is C NJ to SE PA where there is 3-4" of snow. Link to comment Share on other sites More sharing options...
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