Fozz Posted December 15, 2020 Share Posted December 15, 2020 The NAM appears to be running on schedule, FWIW. 1 Link to comment Share on other sites More sharing options...
ers-wxman1 Posted December 15, 2020 Share Posted December 15, 2020 46 minutes ago, psuhoffman said: This is where our area starts to lose the thermals on the WAA side of the storm. It's a step back on this part. The red line is the 850 but like you said at this point the layer is isothermal from 850 down so its pretty much the rain snow line there...you can see what qpf came before the transition...you can estimate how the area did...northern zones hold on 1-2 hours longer...south of DC gets very little snow before going to rain. 1z here is about the worst look for the thermals. This is the NW extent of both the surface and mid level warmth. I have estimated the rain and sleet lines here by tracing the 925 and 850 0 lines. 2 hours later by 3z the temps are crashing and I would estimate everyone NW of 95 is going back to snow or has already. There are some pockets in the zone of subsidence NW of the developing banding of warmth but if they are between heavy bands at the time your not missing out on much accumulation anyways...point is I think we can assume from 3z on anything that falls is snowfall from 95 NW SO this last plot is the qpf that falls after that...and this is where the bulk of the snow comes from. This looks great...I would sign up for it...but I do NOT like living on the deform love as 90% of the storm. That can disapear real quick if things don't come together right. But the euro has been remarkably consistent with that in our area so maybe... so there is good and bad here...but again I am nervous relying almost entirely on the back side. Even up here its only about 3-4" before a flip to sleet...the other 14" if gives me is from the deform. If that happens GREAT but my rule is usually to treat that as bonus. Anyways... hope that helped. This is a very good analysis. 2 Link to comment Share on other sites More sharing options...
wizard021 Posted December 15, 2020 Share Posted December 15, 2020 53 minutes ago, AmericanWxFreak said: Gross. A couple over Balt and a couple headed for Bermuda... The furtheast east will verify. 2 Link to comment Share on other sites More sharing options...
AmericanWxFreak Posted December 15, 2020 Share Posted December 15, 2020 Nam looking pretty amped 1 Link to comment Share on other sites More sharing options...
ovechkin Posted December 15, 2020 Share Posted December 15, 2020 I don’t post much bc I’m not that smart, but nearly 50 years of DC living and I’ve seen this movie before. Supposed to be 29 tonight. Probably won’t drop below 35 at DCA. Then tomorrow will hit 45 easily. Then start to drop, then clouds build in hold temp above freezing and even if dews are low we get 30 minutes in the AM of snow that melts on contact and then it switches over and game set match. we have barely touched freezing this season, the track sucks, the airmass sucks, the water temps suck. This storm feels like walking up a down escalator. With PHL and NYC butts staring down at us from the top. 2 13 Link to comment Share on other sites More sharing options...
winterymix Posted December 15, 2020 Share Posted December 15, 2020 26 minutes ago, WxMan1 said: Hello all... A note from NCEP Central Ops, as I am just spinning up at work... There's an issue with one of the supercomputers...which is currently causing a delay in the 00Z model production. Certainly the 00Z HRRR and RAP have been delayed, and the NAM will likely be as well. Sorry folks...just passing along what I know.. "Mom and Dad: the computer ate my homework." Link to comment Share on other sites More sharing options...
clskinsfan Posted December 15, 2020 Share Posted December 15, 2020 NAM out to 39 on IWM. First flakes at 15z Link to comment Share on other sites More sharing options...
EastCoast NPZ Posted December 15, 2020 Share Posted December 15, 2020 3 minutes ago, ovechkin said: I don’t post much bc I’m not that smart, but nearly 50 years of DC living and I’ve seen this movie before. Supposed to be 29 tonight. Probably won’t drop below 35 at DCA. Then tomorrow will hit 45 easily. Then start to drop, then clouds build in hold temp above freezing and even if dews are low we get 30 minutes in the AM of snow that melts on contact and then it switches over and game set match. we have barely touched freezing this season, the track sucks, the airmass sucks, the water temps suck. This storm feels like walking up a down escalator. With PHL and NYC butts staring down at us from the top. You should post more. 2 4 Link to comment Share on other sites More sharing options...
SomeguyfromTakomaPark Posted December 15, 2020 Share Posted December 15, 2020 4 minutes ago, ovechkin said: I don’t post much bc I’m not that smart, but nearly 50 years of DC living and I’ve seen this movie before. Supposed to be 29 tonight. Probably won’t drop below 35 at DCA. Then tomorrow will hit 45 easily. Then start to drop, then clouds build in hold temp above freezing and even if dews are low we get 30 minutes in the AM of snow that melts on contact and then it switches over and game set match. we have barely touched freezing this season, the track sucks, the airmass sucks, the water temps suck. This storm feels like walking up a down escalator. With PHL and NYC butts staring down at us from the top. That is a good point about barely touching freezing. Coldest in mby has probably been like 29. Link to comment Share on other sites More sharing options...
Weather Will Posted December 15, 2020 Share Posted December 15, 2020 WB 1pm Wed NAM tick colder 3 Link to comment Share on other sites More sharing options...
AmericanWxFreak Posted December 15, 2020 Share Posted December 15, 2020 Nam looking pretty amped Link to comment Share on other sites More sharing options...
AmericanWxFreak Posted December 15, 2020 Share Posted December 15, 2020 1 1 Link to comment Share on other sites More sharing options...
Weather Will Posted December 15, 2020 Share Posted December 15, 2020 4pm 1 Link to comment Share on other sites More sharing options...
Weather Will Posted December 15, 2020 Share Posted December 15, 2020 7pm 925/850 1 Link to comment Share on other sites More sharing options...
Scraff Posted December 15, 2020 Share Posted December 15, 2020 8 minutes ago, ovechkin said: I don’t post much bc I’m not that smart, but nearly 50 years of DC living and I’ve seen this movie before. Supposed to be 29 tonight. Probably won’t drop below 35 at DCA. Then tomorrow will hit 45 easily. Then start to drop, then clouds build in hold temp above freezing and even if dews are low we get 30 minutes in the AM of snow that melts on contact and then it switches over and game set match. we have barely touched freezing this season, the track sucks, the airmass sucks, the water temps suck. This storm feels like walking up a down escalator. With PHL and NYC butts staring down at us from the top. Sup Ovi! As a huge Caps fan who also loves a good laugh, please don’t be shy here. More posts! 2 1 Link to comment Share on other sites More sharing options...
AmericanWxFreak Posted December 15, 2020 Share Posted December 15, 2020 Link to comment Share on other sites More sharing options...
osfan24 Posted December 15, 2020 Share Posted December 15, 2020 Just now, Weather Will said: 7pm Ouch. Low seems to form somewhere just off the coast between Charleston and Myrtle and it almost comes due north from there. Just a little more easterly component to that movement from that far south would make a major difference by the time it gets up closer to us. Link to comment Share on other sites More sharing options...
ovechkin Posted December 15, 2020 Share Posted December 15, 2020 4 minutes ago, EastCoast NPZ said: You should post more. Thanks. Maybe I will. Will try to bring good luck. We need everything to go right in every storm yet PHL just 120 miles away gets a foot when someone sneezes. Only holding out hope bc we have seen where changeovers don’t happen as modeled. 2/25/07 was supposed to switch over, 2/10/10 even was supposed to. Obviously much different set ups, airmasses and times of year, but predicting 850 and 925 marches can be tricky. That said, anything white on the ground Thursday morning inside the beltway would be a win. 2 Link to comment Share on other sites More sharing options...
Weather Will Posted December 15, 2020 Share Posted December 15, 2020 10pm heading back SE 925/850/surface....please someone explain why it does not snow when all thes levels are below freezing west of 95? What don’t I understand? 1 Link to comment Share on other sites More sharing options...
DDweatherman Posted December 15, 2020 Share Posted December 15, 2020 Just now, osfan24 said: Ouch. Low seems to form somewhere just off the coast between Charleston and Myrtle and it almost comes due north from there. Just a little more easterly component to that movement from that far south would make a major difference by the time it gets up closer to us. Truth be told, the SLP track on the NAM has improved the last 3 runs and is in one of the better places of what we've seen this afternoon. One more nudge in the same direction and its a pretty solid hit. The 850 temps on the NAM are just a total torch. with the low E of VA Beach where the NAM has it with any other models thermals and we are all in the game. Link to comment Share on other sites More sharing options...
AmericanWxFreak Posted December 15, 2020 Share Posted December 15, 2020 Holy CCB for PA. Here comes.the 40"+ NAM run lol Link to comment Share on other sites More sharing options...
DDweatherman Posted December 15, 2020 Share Posted December 15, 2020 Just now, Weather Will said: 10pm heading back SE 925/850 This is more in line with what you'd expect. With any sort of CCB over the area (which the NAM just trended too this run - huge CCB over the M/D and S PA), these temps crash as shown with a 998 E of OC/Lewes. Link to comment Share on other sites More sharing options...
MN Transplant Posted December 15, 2020 Author Share Posted December 15, 2020 Nice line of thunderstorms in NC on the nest. No comment necessary for the DC area. 1 1 Link to comment Share on other sites More sharing options...
DDweatherman Posted December 15, 2020 Share Posted December 15, 2020 Snow maps on IWM are a decent improvement at the fall line and slightly SE from 18z. 3" line gets down closer to DC on this run. Link to comment Share on other sites More sharing options...
AmericanWxFreak Posted December 15, 2020 Share Posted December 15, 2020 Link to comment Share on other sites More sharing options...
WxMan1 Posted December 15, 2020 Share Posted December 15, 2020 26 minutes ago, Fozz said: The NAM appears to be running on schedule, FWIW. Yeah, it looks like the delays impacted the HRRR. Link to comment Share on other sites More sharing options...
NorthArlington101 Posted December 15, 2020 Share Posted December 15, 2020 Man, if we could just get rid of this double-barreled look on the 3k... 996 at the benchmark man. 2 Link to comment Share on other sites More sharing options...
MN Transplant Posted December 15, 2020 Author Share Posted December 15, 2020 DC Beltway gets a last moment stick save at 3z with the back side whitening the ground on the 3km. Link to comment Share on other sites More sharing options...
osfan24 Posted December 15, 2020 Share Posted December 15, 2020 Low placement and direction is still odd. Off Charleston, almost due north to just south of NC/VA border, then jumps ENE to just south of Eastern Shore, and resumes heading NNE just barely off the Delmarva. Link to comment Share on other sites More sharing options...
DDweatherman Posted December 15, 2020 Share Posted December 15, 2020 Just now, MN Transplant said: DC Beltway gets a last moment stick save at 3z with the back side whitening the ground on the 3km. Thoughts on the NAM? Truthfully, as NA mentioned, the track has improved. It does show a huge CCB like the Euro has had, just northward into C PA. There are some decent takeaways if we're going to dissect it. Link to comment Share on other sites More sharing options...
Recommended Posts