nj2va Posted February 19, 2019 Share Posted February 19, 2019 Created an obs thread. @WxUSAF would you mind pinning this and unpin the current Obs thread? Link to comment Share on other sites More sharing options...
BaltimoreWxGuy Posted February 19, 2019 Share Posted February 19, 2019 There must be a lot of sleet on the GFS around 1-4pm that the conditional maps aren’t picking up on because the clown maps are still crazy. Link to comment Share on other sites More sharing options...
midatlanticweather Posted February 19, 2019 Share Posted February 19, 2019 34 minutes ago, high risk said: That's extremely apparent if one looks at the NAM QPF for southern MD. yes- at least on the NAM - Euro kind of leaned that way previously, but came in better at 6z. GFS kind of agrees, but I suspected a bit south. And it is PA now that looks like the best thump - sleet and FZ for Nova and MD - except the Mts do well with the WAA thump. The 2-4 inch call for Nova and Southern MD - probably better bet. Link to comment Share on other sites More sharing options...
BaltimoreWxGuy Posted February 19, 2019 Share Posted February 19, 2019 The snow depth map is nearly identical to 6z idk, maybe it’s not as bad as the conditional shots suggest Link to comment Share on other sites More sharing options...
ers-wxman1 Posted February 19, 2019 Share Posted February 19, 2019 GFS is next to useless at this point. It’s not going to capture the CAD and erodes the cold air to fast. Link to comment Share on other sites More sharing options...
usedtobe Posted February 19, 2019 Share Posted February 19, 2019 23 minutes ago, WxUSAF said: Glad I’m in good company @usedtobe! I’d still lean toward the euro on total precip and the NAM more for temps and thermal profile. Thanks but I like the CWG forecast of 2 to 5 for the city and 3 to 7 or 4 to 7 father out towards the northwest. I don't trust the GFS amounts so lik eyou I'd lean towards the Euro amounts and the NAM timing of the changeover. The bottom axis of really heavy precip will determine our fate. Link to comment Share on other sites More sharing options...
psuhoffman Posted February 19, 2019 Share Posted February 19, 2019 Rgem still targets DC with best banding. Link to comment Share on other sites More sharing options...
Wonderdog Posted February 19, 2019 Share Posted February 19, 2019 4 hours ago, BristowWx said: Agree that’s spot on. Taking off for this one regardless of OPM. Someone has to watch the thermometer at my house and do obs. Making sure you see snow for the first time this year, eh? Link to comment Share on other sites More sharing options...
mattb65 Posted February 19, 2019 Share Posted February 19, 2019 Here's the sounding at Hour 30 for the DC metro region - it painted this as snow on the 6z run and as mix on the current run, by this point approximatel 0.4" QPF has falling, prior runs had 0.5-0.75" QPF. It's a relatively minor difference and probably rate dependent. I think with a sounding like this it would be snow in heavy precip or snow/sleet mix in lighter precip. I personally don't see this GFS run as some huge step back, just another variation of the same with probably ~0.3-0.4" of QPF falling before we lose the column in the DC metro region - supports 2-4" of snow before we flip with some boom potential if big rates come in with the initial bands. Link to comment Share on other sites More sharing options...
HighStakes Posted February 19, 2019 Share Posted February 19, 2019 Just now, mappy said: So, the GFS seems better for places north and west. by 06z Thursday is 1.6 IMBY, previous GFS was 1.3. Flip looks about the same time IMBY (18z). My best guess for us is 3-4. Then sleet for a couple hours. Then a pretty good glazing. Would not be surprised if we flip to sleet a little soon than expected as the warm nose tends to race north in these type of events. If it holds off for a bit due to better banding then we could do well. I dont think we get above freezing until very late tomorrow evening perhaps midnight. I think our max potential is 5-6 if we can snow a little past 18z with some decent banding. I'm going with the euro. It been rock solid so far. Hopefully it holds at 12z. Link to comment Share on other sites More sharing options...
stormtracker Posted February 19, 2019 Author Share Posted February 19, 2019 1 minute ago, mattb65 said: Here's the sounding at Hour 30 for the DC metro region - it painted this as snow on the 6z run and as mix on the current run, by this point approximatel 0.4" QPF has falling, prior runs had 0.5-0.75" QPF. It's a relatively minor difference and probably rate dependent. I think with a sounding like this it would be snow in heavy precip or snow/sleet mix in lighter precip. I personally don't see this GFS run as some huge step back, just another variation of the same with probably ~0.3-0.4" of QPF falling before we lose the column in the DC metro region - supports 2-4" of snow before we flip with some boom potential if big rates come in with the initial bands. Ah, good post. I was comparing the pretty colors on TT before I dug into it. I mean, it's the GFS and CAD, so I'm not too alarmed unless the mesos follow suit, which I doubt at this point. Link to comment Share on other sites More sharing options...
Hyphnx Posted February 19, 2019 Share Posted February 19, 2019 FV3 has light snow starting at 03z in RIC. Still snowing at 06z and the snow reaches DC at 06z. Ice starts in RIC at around 12z and the heavy snow reaches DC at 12z. Sleet begins in RIC at 15z, heavy snow in DC at 15z before the flip. Link to comment Share on other sites More sharing options...
yoda Posted February 19, 2019 Share Posted February 19, 2019 FWIW, which is probably next to nothing, the 12z CMC looks better if we are to believe the snow maps lol Link to comment Share on other sites More sharing options...
stormtracker Posted February 19, 2019 Author Share Posted February 19, 2019 Heh, the RGEM is sick. Just took a peek. I wish this was a varsity level meso model. Take a look at it if you haven't already if you're in the DC area. Link to comment Share on other sites More sharing options...
mappy Posted February 19, 2019 Share Posted February 19, 2019 Just now, HighStakes said: My best guess for us is 3-4. Then sleet for a couple hours. Then a pretty good glazing. Would not be surprised if we flip to sleet a little soon than expected as the warm nose tends to race north in these type of events. If it holds off for a bit due to better banding then we could do well. I dont think we get above freezing until very late tomorrow evening perhaps midnight. I think our max potential is 5-6 if we can snow a little past 18z with some decent banding. I'm going with the euro. It been rock solid so far. Hopefully it holds at 12z. Agreed, though I think we could see 4-6" with an upside if more if the cold holds on and we get under a good band. you, sparky, losetoa6 and PSU will do a touch better than me. I'm on the low end of the range compared to you guys. Link to comment Share on other sites More sharing options...
MN Transplant Posted February 19, 2019 Share Posted February 19, 2019 1 minute ago, stormtracker said: Heh, the RGEM is sick. Just took a peek. I wish this was a varsity level meso model. Take a look at it if you haven't already if you're in the DC area. That's what the HRRR was doing at 12z. A beatdown just as we were in danger of flipping. Link to comment Share on other sites More sharing options...
WxUSAF Posted February 19, 2019 Share Posted February 19, 2019 Just now, stormtracker said: Heh, the RGEM is sick. Just took a peek. I wish this was a varsity level meso model. Take a look at it if you haven't already if you're in the DC area. RGEM/ICON/extended HRRrR isn’t the best team but at least we’re on the field playing? Just reinforces the idea that whoever ends up under that moisture plume will jackpot. Will be somewhere between EZF and Harrisburg PA. Link to comment Share on other sites More sharing options...
stormtracker Posted February 19, 2019 Author Share Posted February 19, 2019 Just now, MN Transplant said: That's what the HRRR was doing at 12z. A beatdown just as we were in danger of flipping. Yeah, I read your post and looked and exactly as you said, right when the sleet line could see the whites of our eyes, the heavy precip pushed it back. Link to comment Share on other sites More sharing options...
nj2va Posted February 19, 2019 Share Posted February 19, 2019 1 minute ago, stormtracker said: Heh, the RGEM is sick. Just took a peek. I wish this was a varsity level meso model. Take a look at it if you haven't already if you're in the DC area. Wow. 0.4"+ by 15z for DC. I wish it was a reliable model. Hrdrps has a little better track record (I think)...will be interested to see if it holds from its previous runs. Link to comment Share on other sites More sharing options...
stormtracker Posted February 19, 2019 Author Share Posted February 19, 2019 Just now, WxUSAF said: RGEM/ICON/extended HRRrR isn’t the best team but at least we’re on the field playing? Just reinforces the idea that whoever ends up under that moisture plume will jackpot. Will be somewhere between EZF and Harrisburg PA. I agree...it's going to come down to nowcasting during go time. I seriously doubt the models reach some amazing consensus between now and then on where the jackpot will be. Link to comment Share on other sites More sharing options...
NorthArlington101 Posted February 19, 2019 Share Posted February 19, 2019 1 minute ago, stormtracker said: Yeah, I read your post and looked and exactly as you said, right when the sleet line could see the whites of our eyes, the heavy precip pushed it back. Looks like the HDRPS did yesterday with two distinct W-E max bands. 12z CMC kinda does that as well. Link to comment Share on other sites More sharing options...
MillvilleWx Posted February 19, 2019 Share Posted February 19, 2019 Thought I'd share something in regards to surface temperatures for tomorrow evening which will be a wild card in the extension of frozen precip. Take a look at the GFS trends in surface winds and temperatures compared to the Nam 3km. Notice how the winds on the GFS are breezy out of the south-southeast and the Nam 3km is light out of the east with a much more defined CAD wedge. This is the reason for the GFS trending to all rain sooner compared to the higher resolution guidance. The GFS weakens the surface inversion significantly and allows a deeper mixing of warmer air into the lower profile. 3km on the other hand holds on and the shallow depth of cold air allows for a prolonged period of ZR across a good chunk of the sub-forum (Mainly west of the fall line). Climo will undoubtedly have some impacts on how the event transpires, like always, so if you know how temps behave in WAA regimes like this, you can probably guess what's going to happen. The main question right now is the initial thump for snow and the timing of the strongest low to mid level frontogenesis and the placement of best banding to help alleviate the warmer air mixing into the profile. Best snow potential will run from 9z in Central VA to as late as 18z up in the northern part of the sub-forum. Added orographic enhancements will likely occur as well, so mini jacks will be possible, but we won't know where that will occur until game time. General climo favors Parrs Ridge, Catoctins, and areas along I-81 out to Western MD and high country for WV. Likely will make some adjustments to my first call from yesterday on storm totals based on latest guidance. Link to comment Share on other sites More sharing options...
HighStakes Posted February 19, 2019 Share Posted February 19, 2019 3 minutes ago, mappy said: Agreed, though I think we could see 4-6" with an upside if more if the cold holds on and we get under a good band. you, sparky, losetoa6 and PSU will do a touch better than me. I'm on the low end of the range compared to you guys. I went conservative because I'm worried about sleet. If we stay under good banding we can hold off the pingers. On the other hand I've seen DC switch to sleet and it races up here an hour later. Nonetheless it's a fun event to track and my bar is 4. Link to comment Share on other sites More sharing options...
mappy Posted February 19, 2019 Share Posted February 19, 2019 2 minutes ago, HighStakes said: I went conservative because I'm worried about sleet. If we stay under good banding we can hold off the pingers. On the other hand I've seen DC switch to sleet and it races up here an hour later. Nonetheless it's a fun event to track and my bar is 4. Cheers to that, friend! Link to comment Share on other sites More sharing options...
mappy Posted February 19, 2019 Share Posted February 19, 2019 Just now, losetoa6 said: Not necessarily . That warm nose at 700mb trajectory is coming SW to ne . You might hold a touch longer ..maybe...lol . I'm thinking anywhere from 3-7" don't get my hopes up! i always flip before you guys do. Link to comment Share on other sites More sharing options...
psuhoffman Posted February 19, 2019 Share Posted February 19, 2019 25 minutes ago, stormtracker said: GFS is definitely the dreaded "step back" probably a quick snow changing over by 18z whereas before it had a heavy thump/band. 23 minutes ago, stormtracker said: I dunno..it's vastly different from everything else with timing. Not sure how to weight it at this point. I don't think its as drastically different as it seems looking at DCA as a specific spot. GFS lacks the resolution to nail exact placement of banding OR correctly factor in mixing and other dynamic influences of that banding....and it sucks with surface tamps from CAD. So you can only get a general idea from it, details are useless. It just misses DC by a few miles with two different bands...just south early and just northwest later and so that specific spot lost snow... plus it warmed SLIGHTLY which hurt a lot in a marginal setup. NOT saying the GFS didn't degrade a little but if you step back and look at the temps and precip over the period it wasnt some huge shift just a couple very minor shifts that bumped DC in the wrong direction in what was a marginal setup to begin with wrt heavy snow totals. Link to comment Share on other sites More sharing options...
psuhoffman Posted February 19, 2019 Share Posted February 19, 2019 28 minutes ago, mappy said: So, the GFS seems better for places north and west. by 06z Thursday is 1.6 IMBY, previous GFS was 1.3. Flip looks about the same time IMBY (18z). It's really hard to use the GFS in these situations because its lack of resolution really forces you to assume a lot about the details. But the GFS blasts our area with some heavy precip between 11am and 3pm. At 18z the column is still cold enough for snow across northern MD...barely. By 0z its toast. But how long it can hold on with mixing of the warm layer with those heavy rates would determine our fate. If we can hold on an extra hour or two during that band (not a crazy idea given the typical mixing and dynamic cooling in such bands) the GFS implies a really good thump up here. @HighStakes It totally depends on the banding. Think of the similar events to this...Feb 2007 (NOT the VD storm the second one), December 2013, Feb 2015 had some similarities too... the area's that get under the heavy bands will hold the column longer. The VV's and heavy precip will help to mix out the mid level warm layer from WAA for a time. If we get under that banding we will get thumped. If we don't...the mid level warmth will race north and its congrats PA. We know the drill. I have no idea where that banding will set up. No one does. We can all make educated guesses. But the idea of a duel max is gaining some traction imo today. Even the guidance that hits our area pretty good "sees" the banding associated with the jet streak up over PA its just not killing the STJ WAA moisture plume into our area as much and is hitting that band up there less. Figuring out those kind of details are above my pay grade though. 15 minutes ago, WxUSAF said: RGEM/ICON/extended HRRrR isn’t the best team but at least we’re on the field playing? Just reinforces the idea that whoever ends up under that moisture plume will jackpot. Will be somewhere between EZF and Harrisburg PA. So my goalposts from 2 days ago are still in the same place LOL... Notice even the guidance that thumps us still has some enhancement up in central PA associated with the jet streak? Its just the NAM is going nuts with that and killing the WAA/STJ moisture feed south of it. The other guidance has more of a duel max idea hinted at between those two areas. That is a much better result for us. Link to comment Share on other sites More sharing options...
poolz1 Posted February 19, 2019 Share Posted February 19, 2019 Looking like this is really juicing up...GOM is wide open and precip is starting to blossom down south. GOES-East Link to comment Share on other sites More sharing options...
yoda Posted February 19, 2019 Share Posted February 19, 2019 FWIW, 15z HRRR at the end of its run begins snow in DCA around 8z WED... CHO around 5z WED Link to comment Share on other sites More sharing options...
Fozz Posted February 19, 2019 Share Posted February 19, 2019 How good are the WRF models (ARW and NMM)? The 0z runs all show a good hit for MD. Link to comment Share on other sites More sharing options...
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