Absolute Humidity Posted December 29, 2012 Share Posted December 29, 2012 FWIW rad cooling has me down to 27 now so at least it feels like winter. I'd be happy to see an inch fall after any changeover back to snow as the low pulls away. Link to comment Share on other sites More sharing options...
threeyoda Posted December 29, 2012 Share Posted December 29, 2012 If anyone has a twitter and doesn't follow Steve D, he's been live updating since about 8pm, and has been very informative on the models coming out plus updates on the current radar and snow reports: "It should be noted the 00Z NAM already busted with snow rates in IN." "over 5 inches in Indy already" "So basically what we are observing tonight is CLEARLY a stronger storm than modeled thus far." "Moderate to heavy snow now developing throughout Ohio River Valley this evening, very much not forecasted." "Does this translate east? I think so and I think so far the RUC is trying to catch on to that aspect." '"Steve...is that precip building off North Carolina coast already?" Yes, it is.' Link to comment Share on other sites More sharing options...
jm1220 Posted December 29, 2012 Share Posted December 29, 2012 I don't get what happened.The models were showing snow with highs near 30 and now they are showing highs near 40. WTF. It's the primary low feature that goes into western PA and causes an easterly fetch (albeit weak). That fetch warms us all up from 900mb on down and we then need winds to turn around to the north, and for dynamics to develop overhead for snow to overcome the low level warmth. The poor airmass we have now allows no room for error either. If we had a nice high wedged in and a low that could get below 30, that weak fetch might not matter. It's the initial primary feature that screws us and keeps it an inland event. We need a fast coastal low development that pivots winds back northerly and dynamics that cause precip to change to a driving snow. Link to comment Share on other sites More sharing options...
nzucker Posted December 29, 2012 Share Posted December 29, 2012 The surface low needs to intensify faster, plain and simple. Take a look at the 950-sfc level. For early afternoon in NYC, this is well above freezing if it's correct. Not going to stick with temps in the 35-37 degree range This looks like a snow sounding plain and simple....the last 50mb of the atmosphere might be +0.5C. Not going to make a difference with the upper levels being plenty cold and evaporational cooling. And as SnowGoose is saying, the models are already underestimating how cold the airmass is. Link to comment Share on other sites More sharing options...
Isotherm Posted December 29, 2012 Share Posted December 29, 2012 Models are notorious for overdoing boundary layer warmth and not accounting for dynamic/evaporational cooling. I always look at the track of a storm to determine whether we're going to be snow, and as a secondary factor I look at temps and dewpoints. A low tracking from the VA Capes to just off the Benchmark in late December with dews in the 20s across the area equals snow to me. Also, why are people looking at NAM/GFS temperatures? 12z ECM had a cold temperature profile that supported accumulating snowfall across the area. The ECM nailed the last storm with 2.5" snowfall here then significant sleet/freezing rain before the change to rain while the NAM/GFS had mostly rain in Westchester until the last minute. The ECM is the steady hand in this storm, showing 2-4" snowfall with cold temperatures. Why people would doubt the King is beyond me... I'd agree w/ the BL warmth comment if we were only talking one low to our SE. But if you recall some of our craptastic winters, the primary holding on, even a weak one, to our NW is a killer for the surface-900mb layer. Hope for a stronger secondary (faster intensification i should say). Link to comment Share on other sites More sharing options...
ORH_wxman Posted December 29, 2012 Share Posted December 29, 2012 This looks like a snow sounding plain and simple....the last 50mb of the atmosphere might be +0.5C. Not going to make a difference with the upper levels being plenty cold and evaporational cooling. And as SnowGoose is saying, the models are already underestimating how cold the airmass is. That didn't look like a snow sounding to me. That's a decent layer of above freezing air. If its snow, its barely glop that sticks. Not saying the sounding is going to verify, but a FRZ level just above 950mb is not very good for a place like NYC. Link to comment Share on other sites More sharing options...
TwcMan Posted December 29, 2012 Share Posted December 29, 2012 Figure I start one.. Currently 29/23 with partly cloudy skies. Link to comment Share on other sites More sharing options...
NorthShoreWx Posted December 29, 2012 Share Posted December 29, 2012 Those splits are more common in Nassau county. In February 1999 there was a storm where the south shore of Nassau saw all rain from about 5am -10am while the entire north shore saw a crippling ice storm with power outages all over the place. 12/19/95 and 2/11//94 also had some notable differences between north and south shore in Nassau but those were mainly sleet/snow differences not rain/snow. I've seen the difference between north - south shores on multiple ocassions, though not so much the past few years. This Christmas eve was a very minor example, but I've got a feeling MBY might be mostly ok tomorrow. FWIW, the soundings I looked at only torch the BL and seem over done. You might be right about starting as snow making the precip incliined to stay as snow. I can see a prettyh good dump with an isothermal sounding verifying. Of course the models could be assuming some enhanced LL SE flow for a while before switching to NE, and if that verified it would certainly take some of the the shine off this event. One of my favorite events that was snow on the north shore and rain on the south shore (or least favorites...its an ambivalent thing due to the overwhelming happy time it was) was when my first son was born at a hospital on the north shore while we were living in our first house on the south shore. The day before he came home about 3 or 4 inches fell at the hospital while it was raining at home. That particular winter (93-94) had a huge difference between the south and north shores (probably about 35-40" vs 55-60") Link to comment Share on other sites More sharing options...
nzucker Posted December 29, 2012 Share Posted December 29, 2012 I'd agree w/ the BL warmth comment if we were only talking one low to our SE. But if you recall some of our craptastic winters, the primary holding on, even a weak one, to our NW is a killer for the surface-900mb layer. Hope for a stronger secondary (faster intensification i should say). I don't need to hope because I live north of the City with some elevation and will stay all snow regardless of coastal development/intensification. If anyone gets screwed, it's not going to be me. Still think people are getting overly worried. It's going to be in the upper 20s/low 30s when snow overtakes the area. How anyone is going to get to near 40F in that situation is beyond me. Link to comment Share on other sites More sharing options...
PB GFI Posted December 29, 2012 Share Posted December 29, 2012 The problem isnt at 850hPa, it is below that... Based on what the system is deepening 150 miles to ur east. Minus 3 at 850 Pls explain to me how 925s warm with a light east wind for 3 hrs torch the are from freezing to 40. 2 days ago a system roared overhead and temps got stuck in the mid 30s. Now it's off to ur east. Ths will b a first to see a system to the bm and c my temps go from 32 to 40 I swear if this happens it will b a first in my life Link to comment Share on other sites More sharing options...
ace0927 Posted December 29, 2012 Share Posted December 29, 2012 If anyone has a twitter and doesn't follow Steve D, he's been live updating since about 8pm, and has been very informative on the models coming out plus updates on the current radar and snow reports: "It should be noted the 00Z NAM already busted with snow rates in IN." "over 5 inches in Indy already" "So basically what we are observing tonight is CLEARLY a stronger storm than modeled thus far." "Moderate to heavy snow now developing throughout Ohio River Valley this evening, very much not forecasted." "Does this translate east? I think so and I think so far the RUC is trying to catch on to that aspect." '"Steve...is that precip building off North Carolina coast already?" Yes, it is.' Snow88 might know more about weather than him... Link to comment Share on other sites More sharing options...
threeyoda Posted December 29, 2012 Share Posted December 29, 2012 Here's an update from Steve D on the NAM. I have a question though - how reputable is he? "The basis behind the warmer forecast is a stronger low near the coast, thus more warm air. HOWEVER...The NAM is already significantly off in the snowfall over the Ohio Valley and warmer than actual observed temperatures just 3 HR." Link to comment Share on other sites More sharing options...
Drz1111 Posted December 29, 2012 Share Posted December 29, 2012 Hard to get excited about this one. Marginal away from the UHI; but with dicey temps, afternoon start and light to moderate rates, this is either not going to accumulate in the urbanized areas or will be a cars-and-tree-boxes slop storm. Wishing it to be colder doesn't make it so. Link to comment Share on other sites More sharing options...
H2Otown_WX Posted December 29, 2012 Share Posted December 29, 2012 This looks like a snow sounding plain and simple....the last 50mb of the atmosphere might be +0.5C. Not going to make a difference with the upper levels being plenty cold and evaporational cooling. And as SnowGoose is saying, the models are already underestimating how cold the airmass is. The depth of the warm layer is a little bit concerning. Looks like it is about 1200 feet but given how close it is to being isothermal at 0C and the GFS' tendency to overdo BL warmth, I don't think it's something that won't be overcome by good precip. rates. Whether or not there really are good precip. rates (> .05 LE/hr) remains to be seen I guess. Link to comment Share on other sites More sharing options...
nzucker Posted December 29, 2012 Share Posted December 29, 2012 Based on what the system is deepening 150 miles to ur east. Minus 3 at 850 Pls explain to me how 925s warm with a light east wind for 3 hrs torch the are from freezing to 40. 2 days ago a system roared overhead and temps got stuck in the mid 30s. Now it's off to ur east. Ths will b a first to see a system to the bm and c my temps go from 32 to 40 I swear if this happens it will b a first in my life It won't happen...meteorology over modelology! Exactly.....the last system cut well to the west, and I didn't go above freezing until the last couple of hours, and then it was to 36F. This is a colder airmass, a better storm track, and a weaker system. Not seeing the warmth. Link to comment Share on other sites More sharing options...
Isotherm Posted December 29, 2012 Share Posted December 29, 2012 I don't need to hope because I live north of the City with some elevation and will stay all snow regardless of coastal development/intensification. If anyone gets screwed, it's not going to be me. Still think people are getting overly worried. It's going to be in the upper 20s/low 30s when snow overtakes the area. How anyone is going to get to near 40F in that situation is beyond me. Well I know that Mt. Zucker will remain snow even with a primary of 980mb in Buffalo. But for the rest of us, hopefully the Euro holds serve with its temp profile and we see a last minute trend toward a quicker coastal deepening. Link to comment Share on other sites More sharing options...
threeyoda Posted December 29, 2012 Share Posted December 29, 2012 Here's an update from Steve D on the NAM. I have a question though - how reputable is he? "The basis behind the warmer forecast is a stronger low near the coast, thus more warm air. HOWEVER...The NAM is already significantly off in the snowfall over the Ohio Valley and warmer than actual observed temperatures just 3 HR." Snow88 might know more about weather than him... Well there's my answer haha Link to comment Share on other sites More sharing options...
mulen Posted December 29, 2012 Share Posted December 29, 2012 I stopped pissing on sparkplugs its gonna snow climatology is our friend 65% of the nation has snow i'll shave my bald ass head if theirs no snowcover real soon in the big apple area. Looks chilly early jan exciting pattern if the ensembles verify price of oil gonna hurt some only downside. Link to comment Share on other sites More sharing options...
nzucker Posted December 29, 2012 Share Posted December 29, 2012 Well I know that Mt. Zucker will remain snow even with a primary of 980mb in Buffalo. But for the rest of us, hopefully the Euro holds serve with its temp profile and we see a last minute trend toward a quicker coastal deepening. Soundings for GFS/NAM look fine at HPN (White Plains). Link to comment Share on other sites More sharing options...
SnowGoose69 Posted December 29, 2012 Share Posted December 29, 2012 Here's an update from Steve D on the NAM. I have a question though - how reputable is he? "The basis behind the warmer forecast is a stronger low near the coast, thus more warm air. HOWEVER...The NAM is already significantly off in the snowfall over the Ohio Valley and warmer than actual observed temperatures just 3 HR." The upper system appears to have been badly underestimated by the models most of the past 24 hours....I posted this morning how the jet dynamics and ridging in the OH Valley were causing alot of aircraft turbulence the models were missing because the heights were kicking up with expanding trops ahead of the vort which was over Oklahoma at the time. It also dropped a surprise 1-2 inches of snow over OK this morning. Its possible tonight's milder solutions may be the models realizing how strong that system is and holding it on longer, the thing is primary lows, especially weak ones usually die faster than the models expect them to, just ask people in the OH Valley during our big storms here how often that happens...if thats the case this time the coastal is probably developing earlier than most guidance shows. Link to comment Share on other sites More sharing options...
Allsnow Posted December 29, 2012 Share Posted December 29, 2012 Advisories should be drop by morning 95-se...coating at best now . What a kick Link to comment Share on other sites More sharing options...
ag3 Posted December 29, 2012 Share Posted December 29, 2012 Well I know that Mt. Zucker will remain snow even with a primary of 980mb in Buffalo. But for the rest of us, hopefully the Euro holds serve with its temp profile and we see a last minute trend toward a quicker coastal deepening. Euro soundings were warm for areas like JFK, ISP, FRG, coastal NJ and borderline for LGA/NYC. Link to comment Share on other sites More sharing options...
nzucker Posted December 29, 2012 Share Posted December 29, 2012 Advisories should be drop by morning 95-se...coating at best now . What a kick Strongly disagree...a lot of LI, especially the North Shore, is going to do very well with this storm. North Shore if SE of I-95 but could have some impressive totals. Link to comment Share on other sites More sharing options...
Isotherm Posted December 29, 2012 Share Posted December 29, 2012 I stopped pissing on sparkplugs its gonna snow climatology is our friend 65% of the nation has snow i'll shave my bald ass head if theirs no snowcover real soon in the big apple area. Looks chilly early jan exciting pattern if the ensembles verify price of oil gonna hurt some only downside. This is the fate of the rest of us if tomorrow fails. Link to comment Share on other sites More sharing options...
readingaccount1 Posted December 29, 2012 Share Posted December 29, 2012 The upper system appears to have been badly underestimated by the models most of the past 24 hours....I posted this morning how the jet dynamics and ridging in the OH Valley were causing alot of aircraft turbulence the models were missing because the heights were kicking up with expanding trops ahead of the vort which was over Oklahoma at the time. It also dropped a surprise 1-2 inches of snow over OK this morning. Its possible tonight's milder solutions may be the models realizing how strong that system is and holding it on longer, the thing is primary lows, especially weak ones usually die faster than the models expect them to, just ask people in the OH Valley during our big storms here how often that happens...if thats the case this time the coastal is probably developing earlier than most guidance shows. Good discussion. A question then arises: Is the primary stronger and the coastal is developing faster? If so, what are ramifications? Another question as well. What is defined as the coast? Immediate shore? 20 miles inland? Link to comment Share on other sites More sharing options...
FPizz Posted December 29, 2012 Share Posted December 29, 2012 25.1 here so far in Piscataway. Still clear for the most part. Forecast low is 25. I guess the warming will start soon. Link to comment Share on other sites More sharing options...
Rtd208 Posted December 29, 2012 Share Posted December 29, 2012 You seriously need to calm down. Advisories should be drop by morning 95-se...coating at best now . What a kick Link to comment Share on other sites More sharing options...
mulen Posted December 29, 2012 Share Posted December 29, 2012 Trials and tribulations of model watching common sense other factors point towards a good shot of snow but the near future is something to look forward to. Link to comment Share on other sites More sharing options...
allgame830 Posted December 29, 2012 Share Posted December 29, 2012 well the banding in southern Indiana is heavier than modeled but we have to see how the effects us to the east. Hopefully it means good news for us but we gotta see. Link to comment Share on other sites More sharing options...
sferic Posted December 29, 2012 Share Posted December 29, 2012 NWS just bumped Liberty up to 7 inches. Link to comment Share on other sites More sharing options...
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