Scarlet Pimpernel Posted December 13, 2022 Share Posted December 13, 2022 17 minutes ago, Weather Will said: WB GFS still has it at freezing NW at 2pm Th. That just has nasty, raw (and rainy, at least near metro areas) day written all over it. Link to comment Share on other sites More sharing options...
Kmlwx Posted December 13, 2022 Share Posted December 13, 2022 3 minutes ago, Weather Will said: Understood, but if we get an inch of liquid with below freezing temps through 2pm in NW suburbs, it won’t be good… But remember - if it is coming down steadily - it's not likely to accrete as easily. Far NW suburbs will definitely be hazardous. I think @mappy is being quite realistic with how our ice events normally turn out. A few spots will definitely be in ice storm territory - but it won't be a widespread significant ice storm outside of FAR NW areas. I'm expecting a slippery sidewalk or two north of Silver Spring, MD...but not much more. 2 Link to comment Share on other sites More sharing options...
clskinsfan Posted December 13, 2022 Share Posted December 13, 2022 19 minutes ago, Weather Will said: WB GFS still has it at freezing NW at 2pm Th. Yeah stays all frozen out here. Looks like a pretty serious ice storm for the southern Shen Valley and quite sleety up here in the Winchester area. I would obviously prefer sleet to ZR. Pretty funny "snow" map from the GFS as well. It went with a sleet bomb this run it appears. 1 Link to comment Share on other sites More sharing options...
Lucketts Life Posted December 13, 2022 Share Posted December 13, 2022 23 minutes ago, midatlanticweather said: Someone left their heat on and the door open in far northern Loudoun and the models see it! Guilty. Doing my best to keep those ice totals down IMBY. 2 Link to comment Share on other sites More sharing options...
aldie 22 Posted December 13, 2022 Share Posted December 13, 2022 2 minutes ago, Lucketts Life said: Guilty. Doing my best to keep those ice totals down IMBY. The insulation in those double wide's in the trailer park must not be great. 3 Link to comment Share on other sites More sharing options...
mappy Posted December 13, 2022 Share Posted December 13, 2022 16 minutes ago, Weather Will said: Understood, but if we get an inch of liquid with below freezing temps through 2pm in NW suburbs, it won’t be good… No doubt this system has some juice in it, but the majority of it will fall as a cold rain, my backyard included. pouring freezing rain doesn't accumulate like freezing drizzle, it runs off before it can freeze on surfaces. And with a modest air mass ahead of the system, surfaces aren't going to be that cold to begin with. I think everyone is going to see a period of sleet, then freezing rain. Most south and east of 95 will change over quickly. NW crew will stay frozen longer, but even then they will turn to a cold pouring rain, with the exception of those way out of west in the mountains. we've done this dance before, everyone should know how it goes. 4 Link to comment Share on other sites More sharing options...
mappy Posted December 13, 2022 Share Posted December 13, 2022 No one pay attention to what happens to our north on Thursday. WAA will be helping them with a good front end thump of snow before any mixing. We are cursed by the closeness of the low, and won't see that snow thump. 1 Link to comment Share on other sites More sharing options...
H2O Posted December 13, 2022 Share Posted December 13, 2022 17 minutes ago, mappy said: No doubt this system has some juice in it, but the majority of it will fall as a cold rain, my backyard included. pouring freezing rain doesn't accumulate like freezing drizzle, it runs off before it can freeze on surfaces. And with a modest air mass ahead of the system, surfaces aren't going to be that cold to begin with. I think everyone is going to see a period of sleet, then freezing rain. Most south and east of 95 will change over quickly. NW crew will stay frozen longer, but even then they will turn to a cold pouring rain, with the exception of those way out of west in the mountains. we've done this dance before, everyone should know how it goes. This. We are fighting climo because we don't have a super cold airmass being left in place as warm air rides over. There will be some ice in what are usually the coldest places. How much places radiate before clouds cap it will determine a lot. E of the fall line knows that warm noses always do well and punch in Link to comment Share on other sites More sharing options...
mappy Posted December 13, 2022 Share Posted December 13, 2022 7 minutes ago, H2O said: This. We are fighting climo because we don't have a super cold airmass being left in place as warm air rides over. There will be some ice in what are usually the coldest places. How much places radiate before clouds cap it will determine a lot. E of the fall line knows that warm noses always do well and punch in Yep, it will be in the 40s for most tomorrow, with lows in the mid 30s tomorrow night ahead of precip. that doesnt bode well for a good WAA snow thump before the column warms up due to the low and its placement. Even up here, I always warm quickly and sleet 1 Link to comment Share on other sites More sharing options...
midatlanticweather Posted December 13, 2022 Share Posted December 13, 2022 Good summary by Peter 3 Link to comment Share on other sites More sharing options...
MN Transplant Posted December 13, 2022 Share Posted December 13, 2022 3 hours ago, DarkSharkWX said: This is what a study found about precipitation rate, wind speed, wetbulb temperatures, and how they correlated to ILR. Freezing rain can occur even with temperatures above freezing, but if the wetbulb temperature is above freezing, freezing rain can't occur. The study generally found that wetbulb temperatures between 27-30F, greater windspeeds, and lighter precipitation rates all contribute to more efficient ice accretion. Here is the link if anyone is interested in it: https://training.weather.gov/wdtd/courses/woc/winter/fcst-hzds/ice-storm-accum/presentation_html5.html This is really good. You are going to have to post it multiple times this winter. I never really considered the wind, but it does physically make sense given latent heating. 1 1 Link to comment Share on other sites More sharing options...
WinterWxLuvr Posted December 13, 2022 Share Posted December 13, 2022 2 hours ago, H2O said: The gallons of beet juice brine that will get put down will render this storm impotent. No kidding. That crap needs to stop 1 Link to comment Share on other sites More sharing options...
WesternFringe Posted December 13, 2022 Share Posted December 13, 2022 6 minutes ago, midatlanticweather said: Good summary by Peter He is literally raining on my (ice) parade Link to comment Share on other sites More sharing options...
mattie g Posted December 13, 2022 Share Posted December 13, 2022 Thursday is going to suck an egg. 1 Link to comment Share on other sites More sharing options...
Terpeast Posted December 13, 2022 Share Posted December 13, 2022 I have an in person meeting planned with my boss at his office Thursday afternoon. Maybe best to do it virtually this time. Link to comment Share on other sites More sharing options...
clueless Posted December 13, 2022 Share Posted December 13, 2022 Pretty sure it will underwhelm. We have been here before. Link to comment Share on other sites More sharing options...
nj2va Posted December 13, 2022 Author Share Posted December 13, 2022 I think LWX will upgrade Garrett to an ice storm warning with their afternoon update. Even if low end of their forecast verifies, still a high impact event coupled with the wind. 1 Link to comment Share on other sites More sharing options...
MN Transplant Posted December 13, 2022 Share Posted December 13, 2022 12 Euro is not too bullish. Still a mess far N and W though. 1 Link to comment Share on other sites More sharing options...
Kleimax Posted December 13, 2022 Share Posted December 13, 2022 Noob question here please don’t roast me, but why do the higher elevations stay colder longer? I thought “cold air sinks” and “heat rises”, so shouldn’t the lower elevations stay colder than the mountains? Link to comment Share on other sites More sharing options...
North Balti Zen Posted December 13, 2022 Share Posted December 13, 2022 29 minutes ago, MN Transplant said: 12 Euro is not too bullish. I’ve added that to my mythical family crest. 1 Link to comment Share on other sites More sharing options...
mappy Posted December 13, 2022 Share Posted December 13, 2022 7 minutes ago, Kleimax said: Noob question here please don’t roast me, but why do the higher elevations stay colder longer? I thought “cold air sinks” and “heat rises”, so shouldn’t the lower elevations stay colder than the mountains? In this case, it is more based on location than elevations itself. With the low coming across the bay towards DE, it is pulling in warmer air off the bay/ocean and that warm air warms the upper atmosphere columns, hence us getting sleet and freezing rain. places out west are further from the low, so that warmer air doesn't rotate in nearly as much and they stay colder longer, and at the surface. Eventually places out west will warm too but stay cold at the surface (this is where their elevation is useful) so they will have a much more prolonged freezing event as the upper columns will be above 32, but the surface at or below freezing. 1 Link to comment Share on other sites More sharing options...
Buddy1987 Posted December 13, 2022 Share Posted December 13, 2022 @Weather Will waiting for the 12Z ice accumulation map off the Euro! Appreciate everything you contribute. After reviewing the 12Z suite, giving me a lot of concern for ice accrual, ESPECIALLY with looking at CAD savvy models, i.e. NAM and Canadian, with their superiority for being able to sniff out CAD related events. Really painting an ugly picture up and down 81 and up 64. Going to be interesting to see what transpires as we close in. I take the GFS and the EURO to an extent with a grain of salt when it comes to these types of setups. 2 Link to comment Share on other sites More sharing options...
psuhoffman Posted December 13, 2022 Share Posted December 13, 2022 9 minutes ago, Kleimax said: Noob question here please don’t roast me, but why do the higher elevations stay colder longer? I thought “cold air sinks” and “heat rises”, so shouldn’t the lower elevations stay colder than the mountains? In general yes so high elevation valleys are the best location for ice. The Shenandoah and some of the valleys in WV get awful ice storms. But higher elevations also advantage from upslope flow which can cool the low levels. It can also enhance precip which further cools all levels. 2 Link to comment Share on other sites More sharing options...
snowmagnet Posted December 13, 2022 Share Posted December 13, 2022 How soon is this storm hitting the I-81 corridor on Wednesday? I know friends who have students coming back to nova from colleges tomorrow…. Link to comment Share on other sites More sharing options...
TSG Posted December 13, 2022 Share Posted December 13, 2022 37 minutes ago, Kleimax said: Noob question here please don’t roast me, but why do the higher elevations stay colder longer? I thought “cold air sinks” and “heat rises”, so shouldn’t the lower elevations stay colder than the mountains? Adding to what Mappy and PSU already said, if you check out the 3k NAM at the onset of precip you can get some clues there. The peaks along the Blue Ridge for example are only a couple degrees colder than the valley (Staunton/Harrisonburg area), but that's enough to have a large difference. Ice will barely accrete right at 32 degrees, you get closer to the upper 20s and it's a very different story. Later on when the warm nose does finally push through at ~925mb, the ridges and valley all switch over to rain around the same time. TL;DR: In this specific setup the high elevations accrete more ice because of conditions at the start, not because they hold onto the cold air longer. Thats also a large part of why these marginal events are so hard to forecast. Small temp swings can make for large changes in precip type/duration. 1 1 Link to comment Share on other sites More sharing options...
WesternFringe Posted December 13, 2022 Share Posted December 13, 2022 7 minutes ago, snowmagnet said: How soon is this storm hitting the I-81 corridor on Wednesday? I know friends who have students coming back to nova from colleges tomorrow…. They should be fine traveling tomorrow. Early Thursday morning is when the freezing rain is modeled to start. Link to comment Share on other sites More sharing options...
yoda Posted December 13, 2022 Share Posted December 13, 2022 Parts of i66 on my way home from work had already been pre-treated 3 Link to comment Share on other sites More sharing options...
WEATHER53 Posted December 13, 2022 Share Posted December 13, 2022 Very strong low pressure to west and very strong high pressure to the north-northeast and neither moving much at all. This looks like a long period of overrunning with the warm air being very slow to takeover, probably not until dark Thursday. If there is enough moisture we get a sleet and snow combo for over 10 hours. But it could be too light and just drizzle. The B transfer just looks like the transfer is very slow to materialize interesting in situ for the obs thread. Link to comment Share on other sites More sharing options...
WEATHER53 Posted December 13, 2022 Share Posted December 13, 2022 4 hours ago, mappy said: no way are people going to see .5-1" of freezing rain. thats stupid. Modeled 2-3 times every winter and occurs 2-3 times every 30 years. 5 Link to comment Share on other sites More sharing options...
jonjon Posted December 13, 2022 Share Posted December 13, 2022 Ice is pretty uncommon here, we don't get help from CAD. This one appears to have the most potential for ice here that I can recall. 3 Link to comment Share on other sites More sharing options...
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