atownwxwatcher Posted October 26, 2011 Share Posted October 26, 2011 PRELIMINARY EXTENDED FORECAST DISCUSSION NWS HYDROMETEOROLOGICAL PREDICTION CENTER CAMP SPRINGS MD 458 AM EDT WED OCT 26 2011 VALID 12Z SUN OCT 30 2011 - 12Z WED NOV 02 2011 USED THE 12Z/25 ECENS MEAN FOR THE PRELIMINARY FRONTS ANDPRESSURES FOR DAY 3...TRANSITIONING TO AN EVEN BLEND OF THE 12Z/25ECENS MEAN AND 00Z/26 GEFS MEAN THEREAFTER. THERE IS STILL A GOODDEAL OF MODEL SPREAD WITH THE HANDLING OF THE WAVE COMING TOGETHERNEAR THE MID ATLANTIC COAST DAY 3...WITH THE UKMET AND A FEW00Z/26 GEFS MEMBERS INDICATING A LOW BOMBING EAST OF NEW JERSEY LATE DAY 3...THEN PASSING CLOSE TO THE ATLANTIC BENCHMARK BEFORE HEADING INTO THE NORTH ATLANTIC AS A DEEP CYCLONE. THE ECENS MEAN GIVES THOSE DEVELOPED SOLUTIONS THEIR DUE IMPORTANCE MORE SO THAN THE GEFS MEAN...WHICH IS WHY IT DOMINATED THE DAY 3 MANUAL BLEND. THEREAFTER...THE UPSTREAM WAVE DIGGING INTO THE SOUTHERN PLAINS IS MORE PROGRESSIVE IN THE GFS...GEFS MEAN...GEM GLOBAL...AND UKMET THAN THE ECMWF AND ECENS MEAN...WITH THE 00Z/26 DETERMINISTIC ECMWF AN OUTLIER CLOSING OFF A MID-LEVEL CENTER OVER THE TENNESSEE VALLEY LATE IN THE PERIOD. GAVE THE SLOWER ECENS MEAN SOLUTION AT LEAST HALF CREDIT WITH THE TROUGH...CONSIDERING THE TENDENCY THIS FALL FOR CLOSED-OFF VORTICES. EVENTUALLY...THIS ENERGY TRANSLATES OFF THE SOUTHEAST COAST AND FORGES A NEW ATLANTIC LOW...WITH LOW CONFIDENCE IN ITS PLACEMENT AND INTENSITY. ALL THE GUIDANCE AGREES ON A FRESH BATCH OF MARITIME POLAR AIR MARCHING ACROSS THE WEST AND ONTO THE HIGH PLAINS BY THE END OF THE FORECAST.CISCO Link to comment Share on other sites More sharing options...
Snow_Miser Posted October 26, 2011 Share Posted October 26, 2011 Yesterday's 12z run was unreal. Also, having the NOGAPS trend west overnight was also promising. Maybe the Euro had a bad run. That is my take on this. If you just say maybe the Euro had a bad run, then ALL of the other models actually trended in a good direction last night. JMA 0Z 72hr. Yeah, 12z will decide if the Euro "had a bad run or not" or if it is meeting a middle compromise with the GFS. It is very interesting though, that every single other model trended west with this storm. Link to comment Share on other sites More sharing options...
tornadojay Posted October 26, 2011 Share Posted October 26, 2011 6z GFS looks similar to the Euro Link to comment Share on other sites More sharing options...
Alpha5 Posted October 26, 2011 Share Posted October 26, 2011 Both models seem to agree on a scraper ATM. We'll see how it goes from here Link to comment Share on other sites More sharing options...
TheTrials Posted October 26, 2011 Share Posted October 26, 2011 should have some better sampling at 12z today even better at 00z tonight and solid sampling tomorrow at 12z, lots of time for solutions to present themselves. Link to comment Share on other sites More sharing options...
TheTrials Posted October 26, 2011 Share Posted October 26, 2011 It's such a delicate setup, just look how close the srefs are and this is well beyond their solid range. Link to comment Share on other sites More sharing options...
bluewave Posted October 26, 2011 Share Posted October 26, 2011 The GFS and Euro moved to more of an intermediate solution that the Euro ensembles have been carrying. The energy in the southern stream gets the low going to far SE. We need the the energy to be more concentated in the northern stream for the storm to form closer in. That's always the challenge in a split flow with a dominant northern branch during a La Nina. Link to comment Share on other sites More sharing options...
jm1220 Posted October 26, 2011 Share Posted October 26, 2011 If it's a "scraper" with just light or mod precip in the area, with the low bombing too late, it will just be rain almost everywhere, guaranteed. We really need this to bomb further south and closer in for the proper dynamics to take shape for snow. Link to comment Share on other sites More sharing options...
TheTrials Posted October 26, 2011 Share Posted October 26, 2011 If it's a "scraper" with just light or mod precip in the area, with the low bombing too late, it will just be rain almost everywhere, guaranteed. We really need this to bomb further south and closer in for the proper dynamics to take shape for snow. yup, it only works one way. Lots of time on this still. Link to comment Share on other sites More sharing options...
SnowGoose69 Posted October 26, 2011 Share Posted October 26, 2011 2 weeks from now this would have a chance to be snow along the coast if it evolved similar to the way previous Euro runs showed, no way could it ever be snow this early in the season even with a near perfect setup. Link to comment Share on other sites More sharing options...
TheTrials Posted October 26, 2011 Share Posted October 26, 2011 2 weeks from now this would have a chance to be snow along the coast if it evolved similar to the way previous Euro runs showed, no way could it ever be snow this early in the season even with a near perfect setup. are you serious? NO WAY it can snow? You can't be absolute, its weather, anything can happen. Link to comment Share on other sites More sharing options...
SnowGoose69 Posted October 26, 2011 Share Posted October 26, 2011 are you serious? NO WAY it can snow? You can't be absolute, its weather, anything can happen. It probably could not snow with any boundary layer profile or 850-1000mb setup we have seen prior to November 5th the last 20 or 30 years or so in a setup with a coastal system near of just off the coast, meaning we'd need some sort of historic type air mass. I'd guess we'd need 850 temps of -10 or -12C all the way to the coast Link to comment Share on other sites More sharing options...
ag3 Posted October 26, 2011 Share Posted October 26, 2011 srefs brush the area with .25"-.50" of precip. Upper levels very cold, but surface is in the upper 40's. Lots of members are leaning west though with the surface low. There's probably a few heavy hitters on the individual members. Link to comment Share on other sites More sharing options...
tornadojay Posted October 26, 2011 Share Posted October 26, 2011 If it can trace on 10/10 - 10/11/1979, then I guess anything is possible on the last few days of October... it's still very tough to do, but it could happen. Link to comment Share on other sites More sharing options...
NEG NAO Posted October 26, 2011 Share Posted October 26, 2011 2 weeks from now this would have a chance to be snow along the coast if it evolved similar to the way previous Euro runs showed, no way could it ever be snow this early in the season even with a near perfect setup. The missing element in the models at this time is the dynamics - you need a system that is a deeper low pressure a few miles closer to the coast - to drag down the cold air to the surface during the event to support snowfall near ground level - Oct 28 2008 was that type of system that started as rain and eventually changed to snow over parts of NJ . The current "scraper" on the models will not support snowfall near the coast and inland areas - western NJ - lower hudson valley in NY would probably see only a few showers or flurries... Link to comment Share on other sites More sharing options...
ag3 Posted October 26, 2011 Share Posted October 26, 2011 It probably could not snow with any boundary layer profile or 850-1000mb setup we have seen prior to November 5th the last 20 or 30 years or so in a setup with a coastal system near of just off the coast, meaning we'd need some sort of historic type air mass. I'd guess we'd need 850 temps of -10 or -12C all the way to the coast Or a dynamic deformation band with extremely heavy precip rates. Link to comment Share on other sites More sharing options...
Scotty Lightning Posted October 26, 2011 Share Posted October 26, 2011 2 weeks from now this would have a chance to be snow along the coast if it evolved similar to the way previous Euro runs showed, no way could it ever be snow this early in the season even with a near perfect setup. are you serious? NO WAY it can snow? You can't be absolute, its weather, anything can happen. I think he's talking about in the big cities.....still too warm with the UHI and the warm ocean water temps(55 around NY harbor to 65 in Cape May). I'd agree with just elevation only for the next few weeks until cold air locks in...unless there was some freak dynamic cooling event. Link to comment Share on other sites More sharing options...
ag3 Posted October 26, 2011 Share Posted October 26, 2011 I think he's talking about in the big cities.....still too warm with the UHI and the warm ocean water temps(55 around NY harbor to 65 in Cape May). I'd agree with just elevation only for the next few weeks until cold air locks in...unless there was some freak dynamic cooling event. I dont think anyone is expecting an all out snowstorm. Most of us are just hoping for a few hours of wet snow, that we know wont really accumulate. Link to comment Share on other sites More sharing options...
SnowGoose69 Posted October 26, 2011 Share Posted October 26, 2011 I think he's talking about in the big cities.....still too warm with the UHI and the warm ocean water temps(55 around NY harbor to 65 in Cape May). I'd agree with just elevation only for the next few weeks until cold air locks in...unless there was some freak dynamic cooling event. Something like 11/11/87 in DC could do it and even then I think their 850s were around -4 to -6C or so. There may be snow flakes, but to get an accumulating snow in the city I cannot imagine what sort of air mass we'd have to have in place. 11/1 vs. 11/10 is a big difference as much as people do not realize it. Same as 11/25 vs. 12/5 is a huge difference in how much easier it is to get it to snow, the setup that got 1 inch in some areas on 11/11/87 won't work 10 days earlier. Link to comment Share on other sites More sharing options...
TheTrials Posted October 26, 2011 Share Posted October 26, 2011 wowzer on the ARW's from the 9z Sref's Link to comment Share on other sites More sharing options...
TheTrials Posted October 26, 2011 Share Posted October 26, 2011 Looks like white plains may end as some wet snow on the NAM, if you believe it. Surface temp is 37 but its below freezing just above that. Not too shabby. Link to comment Share on other sites More sharing options...
MJO812 Posted October 26, 2011 Share Posted October 26, 2011 Maybe some flakes as the 1st storm leaves? Link to comment Share on other sites More sharing options...
supermeh Posted October 26, 2011 Share Posted October 26, 2011 Looks like white plains may end as some wet snow on the NAM, if you believe it. Surface temp is 37 but its below freezing just above that. Not too shabby. Maybe....I am 5 minutes west of White Plains. Link to comment Share on other sites More sharing options...
TheTrials Posted October 26, 2011 Share Posted October 26, 2011 For all the Hudson valley boys, snowing at Stewart Airforce Base Link to comment Share on other sites More sharing options...
SBUWX23 Posted October 26, 2011 Share Posted October 26, 2011 Looks like white plains may end as some wet snow on the NAM, if you believe it. Surface temp is 37 but its below freezing just above that. Not too shabby. Probably just drizzle. Saturation does not get above -10C Link to comment Share on other sites More sharing options...
TheTrials Posted October 26, 2011 Share Posted October 26, 2011 Probably just drizzle. Saturation does not get above -10C Is it ideal snow growth? Not even close. But that is the very end and likely cold enough and saturated enough between 33 and 36 especially the hills. Link to comment Share on other sites More sharing options...
snywx Posted October 26, 2011 Share Posted October 26, 2011 If I had to guess right now I would say areas >1000' here in the far interior can get 2-3" with areas >500' around 1" or so.. And when I say far interior I mean 50+ miles NW Link to comment Share on other sites More sharing options...
LocoAko Posted October 26, 2011 Share Posted October 26, 2011 Is it ideal snow growth? Not even close. But that is the very end and likely cold enough and saturated enough between 33 and 36 especially the hills. Baumgardt (1999) found that if the cloud top temperature is -10C, which it almost exactly is in this case, you only have a 60% chance of ice even existing in the cloud from heterogeneous nucleation, and ice particles are a prerequisite for deposition to occur and snowflakes to grow. It isn't a matter of "not ideal" - it might literally be impossible if saturation doesn't occur at cold enough temperatures. And according to a presentation I recently viewed from CTP, most particles require saturations below -10C. Link to comment Share on other sites More sharing options...
TheTrials Posted October 26, 2011 Share Posted October 26, 2011 Baumgardt (1999) found that if the cloud top temperature is -10C, which it almost exactly is in this case, you only have a 60% chance of ice even existing in the cloud from heterogeneous nucleation, and ice particles are a prerequisite for deposition to occur and snowflakes to grow. It isn't a matter of "not ideal" - it might literally be impossible if saturation doesn't occur at cold enough temperatures. And according to a presentation I recently viewed from CTP, most particles require saturations below -10C. we'll find out, assuming the NAM is even close to being right, and that's a big if. Link to comment Share on other sites More sharing options...
tornadojay Posted October 26, 2011 Share Posted October 26, 2011 12Z NAM doesn't offer too much hope on the second system. Link to comment Share on other sites More sharing options...
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