Cold Rain Posted January 4, 2018 Share Posted January 4, 2018 I think we need a kwik CAD Winter Storm 101 refresher. Link to comment Share on other sites More sharing options...
waronxmas Posted January 4, 2018 Share Posted January 4, 2018 5 hours ago, Justincobbco said: Oh wow! Isn't the National College football championship in Atl this Monday . As long as those folks are intown already (which I suspect a lot of them will be for the festivities) it's all good. The Benz is served by two train stations and is easy walking distance from all the Downtown hotels. Oddly, we already experienced something like this before during the 2000 Super Bowl. In that situation though the ice storm hit the day before. Link to comment Share on other sites More sharing options...
Red1976Red Posted January 4, 2018 Share Posted January 4, 2018 4 hours ago, Queencitywx said: Zip on the euro I was at work when I read this, so I went back and reviewed. Not everyone is "zip" on the euro. The zip area is mainly Charlotte to Winston-Salem. Atlanta metro and north-east sees 3+ hour window of wintry precip during Monday commute. Also, NC mountains and foothills still see enough qpf to be warning criteria if it moves in quicker. Link to comment Share on other sites More sharing options...
CummingGaSnow Posted January 4, 2018 Share Posted January 4, 2018 11 minutes ago, Red1976Red said: I was at work when I read this, so I went back and reviewed. Not everyone is "zip" on the euro. The zip area is mainly Charlotte to Winston-Salem. Atlanta metro and north-east sees 3+ hour window of wintry precip during Monday commute. Also, NC mountains and foothills still see enough qpf to be warning criteria if it moves in quicker. Plus, the NE side of ATL is ALWAYS the hardest place in N GA to dislodge the dammed cold air, so if anything that is the area where the freezing rain COULD last well beyond anywhere else, and if precip decides to come in earlier than scheduled, yikes! My 3 county general rule is Gwinnett to Forsyth to Dawson E/NEward is usually the line of where things can become dicy in a wedge. Link to comment Share on other sites More sharing options...
Hammer Posted January 4, 2018 Share Posted January 4, 2018 I thought precip was supposed to start in N GA by early Monday morning? According to that it's still way back in Western AL.I think that is around midnight our time. I am worried we will be getting hit on the commute. 75 and 285 with winter weather = 🤮🤢. Pro Link to comment Share on other sites More sharing options...
griteater Posted January 5, 2018 Share Posted January 5, 2018 1 hour ago, SN_Lover said: It does not matter if wetbulbs are 20 degrees, if the low tracks north. we can kiss any winter p-type bye bye. This is incorrect. There had been solid ice storms with the primary low in Chicago. As far as this threat goes, I told Mack that this one wouldn't miss to our south, but it's been trending that way with the wave being pressed south into the gulf. Any delay with the precip and the cold will be booking out Link to comment Share on other sites More sharing options...
CummingGaSnow Posted January 5, 2018 Share Posted January 5, 2018 6 minutes ago, griteater said: This is incorrect. There had been solid ice storms with the primary low in Chicago. As far as this threat goes, I told Mack that this one wouldn't miss to our south, but it's been trending that way with the wave being pressed south into the gulf. Any delay with the precip and the cold will be booking out Haven't the last 4 threats that have been modeled to give N GA/Carolinas winter precip gotten suppressed as we got closer? Only difference this time is there's no intense cold coming back in to squash it, right? Link to comment Share on other sites More sharing options...
McDowell_Weather Posted January 5, 2018 Share Posted January 5, 2018 27 minutes ago, CummingGaSnow said: Haven't the last 4 threats that have been modeled to give N GA/Carolinas winter precip gotten suppressed as we got closer? Only difference this time is there's no intense cold coming back in to squash it, right? Yep question is does precp come in before the high scoots ots. Imo and experience it has the look of an ice storm written all over it. One thing i do like is seeing that high move off the coast vs if it was up north with a more classic cad look i would be worried. Hopefully if there is ice it will quickly change to rain. Link to comment Share on other sites More sharing options...
griteater Posted January 5, 2018 Share Posted January 5, 2018 51 minutes ago, CummingGaSnow said: Haven't the last 4 threats that have been modeled to give N GA/Carolinas winter precip gotten suppressed as we got closer? Only difference this time is there's no intense cold coming back in to squash it, right? Yeah, the Euro and UKMet are pinching off the wave, closing it off, and driving it into the gulf...so the precip slows down as it moves in. If the wave will just trek more west to east as an open wave, precip will be thrown into the low level cold airmass over GA and the Carolinas Link to comment Share on other sites More sharing options...
mrdaddyman Posted January 5, 2018 Share Posted January 5, 2018 2 hours ago, Cold Rain said: I think we need a kwik CAD Winter Storm 101 refresher. Just need 3 words: WAA Link to comment Share on other sites More sharing options...
MillerA Posted January 5, 2018 Share Posted January 5, 2018 Gsp ice afternoon disco: Long term /Sunday night through Thursday/... as of 230 PM EST thursday: the medium range forecast starts at 00z Monday with a vigorous southern stream shortwave crossing the Southern Plains within split quasi-zonal upper level flow. Guidance has trended further south/less phased with the northern stream wave, and even closes the low off as it dips southeast toward Florida. With this track, the overall quantitative precipitation forecast trends have been lower, as convection may be more robust upstream of the low-level southwesterly flow along the Gulf Coast. The timing of precip has also been a little slower, with onset perhaps after daybreak Monday, especially along the I-77 corridor. Still, with the slower timing, Sunday night temps will be allowed to drop further into the 20s with dewpts likely in the single digits. So even with precip breaking out toward daybreak or late-morning, sfc temps will likely be sub-freezing such that whatever falls will freeze. The partial thickness nomograms from the three deterministic models generally agree on whatever falls starting out as sleet/freezing rain mix or freezing rain, then transition to rain/freezing rain late morning to midday, before turning to all rain by early aftn. With such dry air in place, despite the parent sfc high drifting well off shore, an in situ wedge will likely develop and keep temps close to freezing a bit longer than previously expected. With all this said, ice accums still look light, generally a tenth of an inch or less. But this will be enough to cause slippery Road conditions. Temps should get into the upper 30s to lower 40s by late aftn and from there stay above freezing Monday night. With the track of the low much further south and a relatively weak high building in from the north, the latest guidance has basically no northwest flow shower activity. In fact, 850 mb temps struggle to get to 0 c, so even any lingering precip may be just rain early Tuesday. But i've cut back pops, resulting in a mostly dry day. Temps will rebound to near normal with some sun breaking out by the aftn, thus ending this long cold wave. From there, the upper flow remains flat for Wednesday, but then starts to amplify with a deep trough to our west for Thursday. Cool high pressure tries to linger to our NE with moist low-level upglide starting to ramp up early Thursday. Temps should remain near normal with increasing clouds and perhaps so light precip developing within the return flow. Link to comment Share on other sites More sharing options...
CAD_Wedge_NC Posted January 5, 2018 Share Posted January 5, 2018 2 hours ago, Cold Rain said: I think we need a kwik CAD Winter Storm 101 refresher. Show me a strong low pressure that takes a southern track in January with very cold soil temps and an arctic air-mass already well established, and I will show you a winter storm for the CAD areas. It will all come down to the amount of moisture that falls and when it begins. Recall that freezing rain is a “self limiting” process. If there is no source for sustained cold air advection, then the latent heat of freezing associated with freezing rain will gradually increase surface temperatures to the freezing mark. Once the temperature reaches 32 degrees, ice no longer accumulates. Now, with the low center passing well south of your particular location, you could have a weak source of cold air advection due to the NE winds over the present snow-pack to our north. That's my 2 cents... for now. Link to comment Share on other sites More sharing options...
SN_Lover Posted January 5, 2018 Share Posted January 5, 2018 15 minutes ago, CAD_Wedge_NC said: Show me a strong low pressure that takes a southern track in January with very cold soil temps and an arctic air-mass already well established, and I will show you a winter storm for the CAD areas. It will all come down to the amount of moisture that falls and when it begins. Recall that freezing rain is a “self limiting” process. If there is no source for sustained cold air advection, then the latent heat of freezing associated with freezing rain will gradually increase surface temperatures to the freezing mark. Once the temperature reaches 32 degrees, ice no longer accumulates. Now, with the low center passing well south of your particular location, you could have a weak source of cold air advection due to the NE winds over the present snow-pack to our north. That's my 2 cents... for now. Name a time the high was to the NW over Iowa and there was a strong low in new england coupled with another low traversing the appalachian that produced a major CAD event. Link to comment Share on other sites More sharing options...
Blue_Ridge_Escarpment Posted January 5, 2018 Share Posted January 5, 2018 7 minutes ago, SN_Lover said: Name a time the high was to the NW over Iowa and there was a strong low in new england coupled with another low traversing the appalachian that produced a major CAD event. The high is not to our NW. Its to our NE over VA/NC line. Link to comment Share on other sites More sharing options...
CummingGaSnow Posted January 5, 2018 Share Posted January 5, 2018 I haven't seen any posts with anyone calling the monday morning event a strong CAD wedge but FFC seems to think so: This is forecasted to be a pretty strong wedge...so am concerned about the high temperatures on Monday. Have adjusted values downward a few degrees within the wedged area, and values could go even lower if the surface low to the south and/or precipitation ends up re-enforcing the cold air in place. I suppose it all boils down to how fast we can get precip in here Monday morning before it has a chance to warm-up. Link to comment Share on other sites More sharing options...
BullCityWx Posted January 5, 2018 Share Posted January 5, 2018 3 hours ago, Red1976Red said: I was at work when I read this, so I went back and reviewed. Not everyone is "zip" on the euro. The zip area is mainly Charlotte to Winston-Salem. Atlanta metro and north-east sees 3+ hour window of wintry precip during Monday commute. Also, NC mountains and foothills still see enough qpf to be warning criteria if it moves in quicker. Allow me to counterpoint, please. I dont think ATL sees much if anything if we believe the Euro. Most of that QPF would probably fall AOB 32 if you believe the models temps. Of course, I think this is all predicated on timing. If it hurries up(which I doubt at this point), it's a much much bigger deal for everyone along 85. In WNC, you get maybe 0.05 of IP and that might be generous. Link to comment Share on other sites More sharing options...
BullCityWx Posted January 5, 2018 Share Posted January 5, 2018 The GEM at 12z arguably is more impressive and is usually the model of choice during ice events. If it can correct south at 0z like I think it will, that could be a bigger deal but I really think all models need to speed this thing up by at least 12 hours and maybe even 18. Link to comment Share on other sites More sharing options...
toxictwister00 Posted January 5, 2018 Share Posted January 5, 2018 00Z NAM (12km) has freezing rain/sleet into Eastern AL by 6z Monday and Atlanta as early as 9z Monday. Link to comment Share on other sites More sharing options...
BullCityWx Posted January 5, 2018 Share Posted January 5, 2018 I'd be a lot more excited about the prospects with this storm if it was just 12 hours quicker. Link to comment Share on other sites More sharing options...
griteater Posted January 5, 2018 Share Posted January 5, 2018 18 minutes ago, Queencitywx said: I'd be a lot more excited about the prospects with this storm if it was just 12 hours quicker. An open wave that kicks on east would do it, but that's not how we are trending at the moment Link to comment Share on other sites More sharing options...
griteater Posted January 5, 2018 Share Posted January 5, 2018 58 minutes ago, CummingGaSnow said: I haven't seen any posts with anyone calling the monday morning event a strong CAD wedge but FFC seems to think so It's strong in the sense of a stout cold, dry airmass, but the surface ridge (damming signature) is weakening Link to comment Share on other sites More sharing options...
NCSNOW Posted January 5, 2018 Share Posted January 5, 2018 Just starting to pay attn to this event. But my 1st thoughts are in line with the 0z run of the nam. We end up with a temporaily closed off lp dropping down into the gom and fizzing out. I'd bet against moisture getting east of the apps in NC currently with a stagnant high anchored over the southern mid atlantic. Well see how she rolls watching h5 trends. Just seems like the past few runs ive glanced at the trend is more and more of a south shift again.Now once we get a return flow on backside of hp tuesday into wed then I could see light moisture getting pulled in on a sw wind over stagnant,modifying air mass. Also think it's possible as we modify back to normal next week with pacific origin air as opposed to Arctic, that we catch alot of hps sliding across lakes,NE and it will skew any runs at a big thaw on east side of apps. Hps will be transient without any blocking to hold them in. So maybe we can time up an overruning event that looks more traditional. Normal will feel like a heat wave when it arrives next week. Link to comment Share on other sites More sharing options...
GunBlade Posted January 5, 2018 Share Posted January 5, 2018 22 minutes ago, griteater said: It's strong in the sense of a stout cold, dry airmass, but the surface ridge (damming signature) is weakening I don’t know how much it applies down to Georgia but here in the Piedmont the cold doesn’t need a high to stick around with the perfect setup. The cold air gets trapped in once moisture arrives and there’s been plenty of cold lately! Unlikely but possible. Link to comment Share on other sites More sharing options...
NCSNOW Posted January 5, 2018 Share Posted January 5, 2018 2 minutes ago, GunBlade said: I don’t know how much it applies down to Georgia but here in the Piedmont the cold doesn’t need a high with the perfect setup. The cold air gets trapped in once moisture arrives and there’s been plenty of cold lately! Unlikely but possible. Agree, but Problem is, if we are sitting directly underneath a 1032 HP per 0z nam, we want have to worry about that wave dropping down ,it'll book it right on out into the gulf. Link to comment Share on other sites More sharing options...
BullCityWx Posted January 5, 2018 Share Posted January 5, 2018 You can make a case that GSP starts as snow this run. Link to comment Share on other sites More sharing options...
Blue_Ridge_Escarpment Posted January 5, 2018 Share Posted January 5, 2018 GFS at hour 90 (18Z Monday) is 5 degrees colder this run at my locale. Link to comment Share on other sites More sharing options...
NCSNOW Posted January 5, 2018 Share Posted January 5, 2018 Hr 90 gfs vort is open and snowing good n ga and sc,nc mtns, couple inches down on clown already. Edit: can't get 2m past hr 72 on gfs, but past hr 90 it has all going to rain up to mason Dixon line. On the flip side looks like another big hp is sliding down across midwest so Mac can turn cold and dry right after the rain moves out. Link to comment Share on other sites More sharing options...
NC_WX10 Posted January 5, 2018 Share Posted January 5, 2018 2 minutes ago, NCSNOW said: Hr 90 gfs vort is open and snowing good n ga and sc,nc mtns, couple inches down on clown already. Am I missing something because I'm not seeing this on the pivotal weather maps? Link to comment Share on other sites More sharing options...
BullCityWx Posted January 5, 2018 Share Posted January 5, 2018 The GFS has everybody back to Morganton at or above freezing by hour 96. Only about .15 showing up for most of the region. Nuisance event at best. Link to comment Share on other sites More sharing options...
JoshM Posted January 5, 2018 Share Posted January 5, 2018 Canadian much colder for Monday PM Decent QPF, too Link to comment Share on other sites More sharing options...
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