Ian Posted December 7, 2013 Share Posted December 7, 2013 it's wrong though. that's not all snow. the flip is pretty quick still. heart of the band at 15z.. already tenuous Link to comment Share on other sites More sharing options...
mitchnick Posted December 7, 2013 Share Posted December 7, 2013 it's wrong though. that's not all snow. the flip is pretty quick still. yeah, I was going to say the 850-0 line is on top of us when all that precip falls Link to comment Share on other sites More sharing options...
usedtobe Posted December 7, 2013 Share Posted December 7, 2013 it's wrong though. that's not all snow. the flip is pretty quick still. The flip at DCA is right around 18Z. My house probably an hour sooner. I mentioned to Jason yesterday that I thought the where the initial band set up would determine who in the area got the two inch amounts. I don't trust the NAMs precip. I'll ride the euro for precip and low level temps. Link to comment Share on other sites More sharing options...
mitchnick Posted December 7, 2013 Share Posted December 7, 2013 can I just say in this thread "oh boy" for end of run? Link to comment Share on other sites More sharing options...
TSSN+ Posted December 7, 2013 Share Posted December 7, 2013 The flip at DCA is right around 18Z. My house probably an hour sooner. I mentioned to Jason yesterday that I thought the where the initial band set up would determine who in the area got the two inch amounts. I don't trust the NAMs precip. I'll ride the euro for precip and low level temps. The nam is pretty good... inside of 3hrs. Link to comment Share on other sites More sharing options...
mitchnick Posted December 7, 2013 Share Posted December 7, 2013 The nam is pretty good... inside of 3hrs. it really is still too far away for the NAM Link to comment Share on other sites More sharing options...
usedtobe Posted December 7, 2013 Share Posted December 7, 2013 heart of the band at 15z.. already tenuous NAM_12_027_38.27;-77.14.gif Yep, isothermal. Probably lots of riming if it is snow, a big if. I'd still go with yesterday's forecast but I could see anything from less than an inch to several inches. I might raise the probability of getting an inch for DCA a tad from yesterday but not by much. Still too many things can go wrong. Link to comment Share on other sites More sharing options...
stormtracker Posted December 7, 2013 Share Posted December 7, 2013 can I just say in this thread "oh boy" for end of run? There's a thread for that Link to comment Share on other sites More sharing options...
usedtobe Posted December 7, 2013 Share Posted December 7, 2013 heart of the band at 15z.. already tenuous NAM_12_027_38.27;-77.14.gif Here's the 18Z. note how the temps are almost the same as 15Z, probably because of the storm lifting and precip burst. Weaken that and the sounding probably will be a tad warmer. Makes any snow forecast a wag at best. Link to comment Share on other sites More sharing options...
wxmeddler Posted December 7, 2013 Share Posted December 7, 2013 That initial band is going to come down to nowcasting... plain and simple. Link to comment Share on other sites More sharing options...
Ian Posted December 7, 2013 Share Posted December 7, 2013 Yeah it's tricky Wes. I'm with you on the NAM. Fwiw my sounding was a bit south of DC for 15z. Right near the center of the highest reflectivity. But this seemed like one of the quicker flip runs though they are all pretty close to eachother Link to comment Share on other sites More sharing options...
winter_warlock Posted December 7, 2013 Share Posted December 7, 2013 when it comes to the NAM in my opinion, It always been best inside of 24 hrs, but ive always thought it has always kinda over did the precip at times Link to comment Share on other sites More sharing options...
TSSN+ Posted December 7, 2013 Share Posted December 7, 2013 Nam too far south with second band I think. RGEM has ice death. Link to comment Share on other sites More sharing options...
Ian Posted December 7, 2013 Share Posted December 7, 2013 latest LWX maps Link to comment Share on other sites More sharing options...
Ian Posted December 7, 2013 Share Posted December 7, 2013 not sure on that ice map.. maybe they don't mean to have the 0 in front of the 1 or 5 edit: though the scale indicates otherwise. confused. Link to comment Share on other sites More sharing options...
TSSN+ Posted December 7, 2013 Share Posted December 7, 2013 latest LWX maps StormTotalIce.png What the heck is that? lol Link to comment Share on other sites More sharing options...
PhineasC Posted December 7, 2013 Share Posted December 7, 2013 Those LWX maps seem pretty whack. Link to comment Share on other sites More sharing options...
winter_warlock Posted December 7, 2013 Share Posted December 7, 2013 latest LWX maps StormTotalSnowRange.png StormTotalIce.png IMO those snow and ice totals seem kinda low especially west Link to comment Share on other sites More sharing options...
snow. Posted December 7, 2013 Share Posted December 7, 2013 The models haven't really changed my thoughts from yesterday's CWG discussion. How low the precip stays sleet is tricky as the models bring in a dry layer and the saturated layer above the warm layer does not get below -8C which usually means freezing rain as you can't form the initial snow crystals. I think you meant freezing drizzle Wes Yeah, my thoughts haven't changed much either, actually going back a few days now. I'm still not expecting as prolonged of a SN or SNPL period as some of the models would suggest IMBY, and I don't expect the IP to be around very ling either. At this point I will gladly take 1-2" of snow and sleet, although my hunch continues to be closer to 1" or less. That warm nose aloft typically comes in faster and more vigorously when we've got more SW flow aloft and to our north (weaker mid level FGEN). There are a few conceptual signatures @ 500 mb by 18-21Z that certainly grab my attention in supporting more liquid pcpn overall (FZRA) with a faster vs. slower transition: SW/WSW flow well north into northern New England and southern Quebec, a bubble/shortwave ridge developing over the GL, and 582 DM heights into Cape Hatteras. IMBY I think the real question is going to be how much ice accretion. The Crofton-Bowie area may sit near 32 for a while Sun evening well into Monday, but depending on the pcpn rates, it's awfully tough to get significant ice buildup with temps so marginal, even along elevated surfaces including trees and power lines. Farther west of 95 (above the fall line), I would think chances of hitting at least .25" of ice go up significantly. Yeah..I've been struggling a bit as to how long we can stay sleet, before flip to freezing rain...seems like a brief window....besides snow formation layer, how long can we stay sleet with 850mb temps above 0? when it happens here, it usually mixes with rain pretty quickly and then changes over. but that scenario often happens at the beginning of a storm....Though I believe on 2/14/07 we were getting heavy sleet with 850mb temps of +3 Link to comment Share on other sites More sharing options...
DDweatherman Posted December 7, 2013 Share Posted December 7, 2013 Yeah..I've been struggling a bit as to how long we can stay sleet, before flip to freezing rain...seems like a brief window....besides snow formation layer, how long can we stay sleet with 850mb temps above 0? when it happens here, it usually mixes with rain pretty quickly and then changes over. but that scenario often happens at the beginning of a storm....Though I believe on 2/14/07 we were getting heavy sleet with 850mb temps of +3 Thats key too, and also when the p-type first flips to sleet, we will have cold 850 temps around 0. There could be a decent small window of about 4-6 hours depending on location that could see sleet. Link to comment Share on other sites More sharing options...
stormtracker Posted December 7, 2013 Share Posted December 7, 2013 not sure on that ice map.. maybe they don't mean to have the 0 in front of the 1 or 5 edit: though the scale indicates otherwise. confused. It would have been a reasonable set of maps had they put up to a tenth of ice for us. Link to comment Share on other sites More sharing options...
BTRWx Posted December 7, 2013 Share Posted December 7, 2013 33% chance of 2-4 inches for the National Mall according to http://www.erh.noaa.gov/lwx/winter/ Link to comment Share on other sites More sharing options...
yoda Posted December 7, 2013 Share Posted December 7, 2013 12z GFS has light snow in C VA at 15z SUN DCA pinging just before 21z Link to comment Share on other sites More sharing options...
snow. Posted December 7, 2013 Share Posted December 7, 2013 GFS is colder..it is all a matter of how long we stay snow when the thump arrives...either way the afternoon should be fun... Link to comment Share on other sites More sharing options...
Bob Chill Posted December 7, 2013 Share Posted December 7, 2013 Nothing surprising. The max precip stripe definitely seems to want to stay e-w oriented just south of DC through the front end stuff. Link to comment Share on other sites More sharing options...
DDweatherman Posted December 7, 2013 Share Posted December 7, 2013 GFS is colder..it is all a matter of how long we stay snow when the thump arrives...either way the afternoon should be fun... For the icy wave of the storm, the GFS really warms up surface temps quickly this run. Hr 42 is the example. Link to comment Share on other sites More sharing options...
eurojosh Posted December 7, 2013 Share Posted December 7, 2013 latest LWX maps StormTotalSnowRange.png StormTotalIce.png When do they post the onset maps? Link to comment Share on other sites More sharing options...
yoda Posted December 7, 2013 Share Posted December 7, 2013 Sucks this run is DCA goes above 32 around 2am... IAD around 4am Link to comment Share on other sites More sharing options...
Ian Posted December 7, 2013 Share Posted December 7, 2013 18/21 soundings near DC Link to comment Share on other sites More sharing options...
DDweatherman Posted December 7, 2013 Share Posted December 7, 2013 Sucks this run is DCA goes above 32 around 2am Going to favor what Will said the other day about the GFS being the worst model with CAD, it retreats the 0c line NW quickly this run. Link to comment Share on other sites More sharing options...
Recommended Posts
Archived
This topic is now archived and is closed to further replies.