Kevin Reilly Posted December 19, 2022 Share Posted December 19, 2022 1 hour ago, EastCoast NPZ said: Warm rain, frozen mud, and shredded Christmas decorations scattered over the property. Hooray. You forgot one scattered power outages too. 1 Link to comment Share on other sites More sharing options...
WinterWxLuvr Posted December 19, 2022 Share Posted December 19, 2022 18 minutes ago, leesburg 04 said: smells like waffles up in here I prefer pancakes … with butter pecan syrup Link to comment Share on other sites More sharing options...
WxUSAF Posted December 19, 2022 Author Share Posted December 19, 2022 51 minutes ago, MN Transplant said: I assume the snow algorithms are just having a tough time with the speed of the front. 47 minutes ago, MN Transplant said: Everything about that map screams temporal resolution problems. Compare with the GGEM on TT. It shows “blue” but with basically no accumulation on the snow maps. I tried to look on Pivotal (with 3hr resolution) to see if there’s a wave that forms on the front and can explain the 1-3” on the GFS. Answer is “maybe”…isobars do look a little baggy as the front passes. Link to comment Share on other sites More sharing options...
osfan24 Posted December 19, 2022 Share Posted December 19, 2022 1 hour ago, midatlanticweather said: Oooo. The downsloping snow hole in my back yard! West to east thunderstorms do this to. I am not sure if this is just a resolution gap, typical f such a scenario, but I swear this happens out my way in summer storms too! Merry Christmas, Ji! Here's some coal in your stocking! 2 Link to comment Share on other sites More sharing options...
Weather Will Posted December 19, 2022 Share Posted December 19, 2022 WB 12Z GEFS 2 Link to comment Share on other sites More sharing options...
North Balti Zen Posted December 19, 2022 Share Posted December 19, 2022 Taking the pup for a walk on the NCR trail in falling snow would be nice for Friday. I would not say no. 2 Link to comment Share on other sites More sharing options...
Paleocene Posted December 19, 2022 Share Posted December 19, 2022 If I were a betting man, I'd take this euro depiction of the result of the frontal passage over the GFS. But it's christmas so I'll believe in the GFS 1 2 Link to comment Share on other sites More sharing options...
paxpatriot Posted December 19, 2022 Share Posted December 19, 2022 2 hours ago, MN Transplant said: Everything about that map screams temporal resolution problems. New way to fail around here with snow maps: temporal resolution problems. As if we needed another one. 2 Link to comment Share on other sites More sharing options...
GATECH Posted December 19, 2022 Share Posted December 19, 2022 20 minutes ago, Paleocene said: If I were a betting man, I'd take this euro depiction of the result of the frontal passage over the GFS. But it's christmas so I'll believe in the GFS It’s got .1 over DCA!!!! Where is the ‘It’s Happening’ gif Link to comment Share on other sites More sharing options...
WEATHER53 Posted December 19, 2022 Share Posted December 19, 2022 As depicted 80mph winds on backside of that low on Friday and Saturday 2 Link to comment Share on other sites More sharing options...
RickinBaltimore Posted December 19, 2022 Share Posted December 19, 2022 4 minutes ago, WEATHER53 said: As depicted 80mph winds on backside of that low on Friday and Saturday At what level? Link to comment Share on other sites More sharing options...
Eskimo Joe Posted December 19, 2022 Share Posted December 19, 2022 9 minutes ago, WEATHER53 said: As depicted 80mph winds on backside of that low on Friday and Saturday Uh, wut? 2 Link to comment Share on other sites More sharing options...
MN Transplant Posted December 19, 2022 Share Posted December 19, 2022 Looks like peak gusts in the mid 40s to around 50 on Friday per the GFS, Euro, and ICON. Potentially higher near the Bay and for our upslope friends. 2 Link to comment Share on other sites More sharing options...
MN Transplant Posted December 19, 2022 Share Posted December 19, 2022 2 hours ago, WxUSAF said: Compare with the GGEM on TT. It shows “blue” but with basically no accumulation on the snow maps. I tried to look on Pivotal (with 3hr resolution) to see if there’s a wave that forms on the front and can explain the 1-3” on the GFS. Answer is “maybe”…isobars do look a little baggy as the front passes. Here's an example from CoolWx, with hourly GFS output. It still has to assign a precip type to an entire hour period, and I'd be willing to be that the little spike there is not all snow precip in the model. Below that is a cool vertical view of the temperature structure. 2 Link to comment Share on other sites More sharing options...
Terpeast Posted December 19, 2022 Share Posted December 19, 2022 5 minutes ago, MN Transplant said: Here's an example from CoolWx, with hourly GFS output. It still has to assign a precip type to an entire hour period, and I'd be willing to be that the little spike there is not all snow precip in the model. Below that is a cool vertical view of the temperature structure. So it looks like around 18-19z when the front crosses DCA? Link to comment Share on other sites More sharing options...
Stormfly Posted December 19, 2022 Share Posted December 19, 2022 55 minutes ago, WEATHER53 said: As depicted 80mph winds on backside of that low on Friday and Saturday Would not be surprised at all to see multiple reports of that... Coming from the Vaisala ultrasonic anemometers that take 10 samples/sec at the top of a 1600 foot multiplex tower! Seriously though, advisory level winds certainly not out of the question and definitely warning criteria for mountains. Link to comment Share on other sites More sharing options...
WEATHER53 Posted December 19, 2022 Share Posted December 19, 2022 1 hour ago, MN Transplant said: Looks like peak gusts in the mid 40s to around 50 on Friday per the GFS, Euro, and ICON. Potentially higher near the Bay and for our upslope friends. Correct and out in the Midwest a 970 low with a 1040 high several hundred miles to west of it would produce 70-80mph winds or gusts. Let’s see if those values of pressure gradient differential verify. The comments I made earlier may not have fully dintinguished I was talking about out there and not DC. Link to comment Share on other sites More sharing options...
DE2PA Posted December 19, 2022 Share Posted December 19, 2022 18Z NAM (in range) wants to hold back the precip and accelerate the cold front. 3 Link to comment Share on other sites More sharing options...
lpaschall Posted December 19, 2022 Share Posted December 19, 2022 CFS has a low off the coast at hr84... 2 Link to comment Share on other sites More sharing options...
high risk Posted December 19, 2022 Share Posted December 19, 2022 2 hours ago, MN Transplant said: Here's an example from CoolWx, with hourly GFS output. It still has to assign a precip type to an entire hour period, and I'd be willing to be that the little spike there is not all snow precip in the model. While some displays are wonky, the GFS (and the other NCEP models) internally do track precipitation at every time step, and if it's falling through a thermal profile that supports snow (or sleet), it will be tallied into the snow bucket. Algorithms, based off of temperature profiles, are used to compute instantaneous precip type, but if we're seeing snow accumulation output, the model integration has precipitation falling into a column supporting either snow or sleet. It gets dicey because the "snowfall" is a liquid equivalent, and users have to apply a ratio, and we all know that the commonly-used 10:1 is often not representative. It's worth noting here, though, that the accumulated snow depth field looks similar to the 10:1 maps. so the model is legitimately accumulating snow on the ground. To be clear, the GFS might be totally wrong with the idea that significant anafrontal precip will fall in this event. But the snow on the GFS maps is not due to weird post-processing. 3 7 Link to comment Share on other sites More sharing options...
WxUSAF Posted December 19, 2022 Author Share Posted December 19, 2022 You all heard it! @high risk says get your shovels ready! 1 14 Link to comment Share on other sites More sharing options...
MN Transplant Posted December 19, 2022 Share Posted December 19, 2022 7 minutes ago, high risk said: While some displays are wonky, the GFS (and the other NCEP models) internally do track precipitation at every time step, and if it's falling through a thermal profile that supports snow (or sleet), it will be tallied into the snow bucket. Algorithms, based off of temperature profiles, are used to compute instantaneous precip type, but if we're seeing snow accumulation output, the model integration has precipitation falling into a column supporting either snow or sleet. It gets dicey because the "snowfall" is a liquid equivalent, and users have to apply a ratio, and we all know that the commonly-used 10:1 is often not representative. It's worth noting here, though, that the accumulated snow depth field looks similar to the 10:1 maps. so the model is legitimately accumulating snow on the ground. To be clear, the GFS might be totally wrong with the idea that significant anafrontal precip will fall in this event. But the snow on the GFS maps is not due to weird post-processing. Good to know. What is the time step now for the GFS? Link to comment Share on other sites More sharing options...
high risk Posted December 19, 2022 Share Posted December 19, 2022 1 minute ago, WxUSAF said: You all heard it! @high risk says get your shovels ready! 1 9 Link to comment Share on other sites More sharing options...
DE2PA Posted December 19, 2022 Share Posted December 19, 2022 What I am relying on from this moment forward 1 1 Link to comment Share on other sites More sharing options...
WEATHER53 Posted December 19, 2022 Share Posted December 19, 2022 Really is going to be a super unique set up to watch unfold. From mid Thursday thru late Sunday, an 80 hour period, a very strong low pressure, moves at 3-5 mph south of the Lakes and achieves a barometric low of 28.80, mostly stays less than 29.30, while bookended by 30.40 barbell highs. Link to comment Share on other sites More sharing options...
Wonderdog Posted December 19, 2022 Share Posted December 19, 2022 That blue over VA on Friday is getting lighter and lighter with each model run. 1 Link to comment Share on other sites More sharing options...
SomeguyfromTakomaPark Posted December 19, 2022 Share Posted December 19, 2022 GFS says 1-2 inches dc to Baltimore. That would be sweet. Link to comment Share on other sites More sharing options...
Scraff Posted December 19, 2022 Share Posted December 19, 2022 6 minutes ago, SomeguyfromTakomaPark said: GFS says 1-2 inches dc to Baltimore. That would be sweet. Just saw that. Would be a miracle honestly, but I’m all chips in on that. Let’s go!! 2 Link to comment Share on other sites More sharing options...
Imgoinhungry Posted December 19, 2022 Share Posted December 19, 2022 This would be thur pm to fri am, yes?. Link to comment Share on other sites More sharing options...
Solution Man Posted December 19, 2022 Share Posted December 19, 2022 3 minutes ago, Scraff said: Just saw that. Would be a miracle honestly, but I’m all chips in on that. Let’s go!! Looks like chances are on the increase Link to comment Share on other sites More sharing options...
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