MN Transplant Posted January 28, 2021 Share Posted January 28, 2021 Dew point at DCA for 00z Monday 12z NAM: 27 06z GFS: 35 06z GFS para: 32 00z Euro: 26 12 Link to comment Share on other sites More sharing options...
clskinsfan Posted January 28, 2021 Share Posted January 28, 2021 8 minutes ago, osfan24 said: A repeat of that would be awesome! Gotta see some juicier runs soon! Not for all of us it wouldnt. That storm kind of sucked out here. 1 Link to comment Share on other sites More sharing options...
Ralph Wiggum Posted January 28, 2021 Share Posted January 28, 2021 3 minutes ago, MN Transplant said: Dew point at DCA for 00z Monday 12z NAM: 27 06z GFS: 35 06z GFS para: 32 00z Euro: 26 Old EE rule in effect (Euro/ETA) 1 Link to comment Share on other sites More sharing options...
Hurricanegiants Posted January 28, 2021 Share Posted January 28, 2021 FWIW I just watched Bernie Rayno’s update. He wasn’t bullish—definitely cautious as he kept focusing on the upper level still being a rather large question mark to steer the coastal pivot etc...I don’t believe we have seen any models that lack that formation up to this point correct? Link to comment Share on other sites More sharing options...
SomeguyfromTakomaPark Posted January 28, 2021 Share Posted January 28, 2021 Just now, Hurricanegiants said: FWIW I just watched Bernie Rayno’s update. He wasn’t bullish—definitely cautious as he kept focusing on the upper level still being a rather large question mark to steer the coastal pivot etc...I don’t believe we have seen any models that lack that formation up to this point correct? Yeah pretty much every model forms a coastal but there is obviously still a big question mark as to where it delivers the biggest impacts. If I was a forecaster I'd be focused on telling the public that some accumulating snow is likely Sunday and Sunday night and the impacts of the coastal on Monday are yet to be determined. 1 Link to comment Share on other sites More sharing options...
Hurricanegiants Posted January 28, 2021 Share Posted January 28, 2021 Got it. Thank you Link to comment Share on other sites More sharing options...
LP08 Posted January 28, 2021 Share Posted January 28, 2021 Hr90 finally updated on the 6z euro. Tick south that matches with what the EPS spit out. Colder and beginning to transfer. 5 7 Link to comment Share on other sites More sharing options...
Dabuckeyes Posted January 28, 2021 Share Posted January 28, 2021 5 minutes ago, DCTeacherman said: Yeah pretty much every model forms a coastal but there is obviously still a big question mark as to where it delivers the biggest impacts. If I was a forecaster I'd be focused on telling the public that some accumulating snow is likely Sunday and Sunday night and the impacts of the coastal on Monday are yet to be determined. I agree. Just give folks a generalization right now and work on the details as we get even closer. Bernie has been burned a couple times already this year, so that may also play into his current forecast. Link to comment Share on other sites More sharing options...
Maestrobjwa Posted January 28, 2021 Share Posted January 28, 2021 44 minutes ago, losetoa6 said: February 9-10, 2010 Miller B HECS had the primary into Ohio fwiw then a tucked coastal off Delaware Ah so that one tucked off of Delaware? That would explain the period freezing rain mixed in that the 19 year-old me was shamefully whining about...lol (even after all that we still got 19 inches in the city!) 1 Link to comment Share on other sites More sharing options...
LeesburgWx Posted January 28, 2021 Share Posted January 28, 2021 18 minutes ago, clskinsfan said: Not for all of us it wouldnt. That storm kind of sucked out here. It’s tough as someone in our subforum has to lose in order for the majority to win and maximize the potential. Whether it’s you out in Winchester or those SE of DC, someone has to lose as a standard due to climo, location, and storm track. 1 Link to comment Share on other sites More sharing options...
ryanconway63 Posted January 28, 2021 Share Posted January 28, 2021 No improvements on the ICON from what I can tell Link to comment Share on other sites More sharing options...
psuhoffman Posted January 28, 2021 Share Posted January 28, 2021 @H2O You brought up very legit points last night. Before things get crazy let me explain why suppression is my bigger concern in this situation. Partly its about hedging bets. Given the confluence to our north, the high, and the cold as the wave approaches...I see virtually no way we get totally blanked with a cutter scenario. At the least we would get a nice WAA thump snow to dry slot. Maybe that isn't the 1-2 feet some are acting like we NEED for this not to bust...but I have 2 kids that are literally asking EVERYDAY when is it going to snow and to them there is almost no difference between 4" and 12". Frankly...20" is probably TOO much for them lol. I will still take it...they can wait for it to melt some! So my first consideration is "how do we avoid the total fail" where my ground ends up bare or with some pathetic amount that precludes sledding, snow fort building and the such. And IMO that is suppressed. Rooting against suppressed may mute the chances of the 2 foot solution some...but the math in my head I separate the boom (12"+) and the bust (less then 4") scenarios. Rooting for a more squashed wave might increase the boom but it increases the bust with this. So I would take a 50/10 (boom% v bust%) type split over a 70/40 type split. Also...frankly just looking at the h5 flow over the top of us and to the NE, I think the degree to which this can go north is muted. The flow is relaxing yes but its still pretty compressed to our northeast as the system enters the midwest. The further south guidance just "feels" more realistic. I can be wrong. I've been wrong. Just my gut. Lastly...the biggest risk, as I told Ji like 3 days ago...is a split. A suppression with the WAA wave then a slow primary that meanders northwest of us causing a late secondary that misses us northeast. But that is still "suppression" imo because the WAA wave is our bread and butter less likely to fail option. The CCB of a developing secondary coastal is ALWAYS a risky proposition and better to be taken as bonus not relied on. All that said...obviously I am human and biased and the fact I live on the northern tip of our geographic region needs to be taken into consideration. But even for places like Baltimore and Frederick and Winchester...I think my thoughts are valid. If I lived south of DC I would probably have a totally different preference for how I want this to evolve. 3 3 Link to comment Share on other sites More sharing options...
SpeedyWX Posted January 28, 2021 Share Posted January 28, 2021 Anyone have a sec for a newie question? Lots of comments about the initial thump, and it being cold powder, and referring to it as WAA. Which I understand is warm air advection. How does WARM air advection translate to cold powder? Thanks. Link to comment Share on other sites More sharing options...
SomeguyfromTakomaPark Posted January 28, 2021 Share Posted January 28, 2021 3 minutes ago, ryanconway63 said: No improvements on the ICON from what I can tell Yeah looks like the coastal impacts are still well north of our region. On to the good models now. 1 Link to comment Share on other sites More sharing options...
jaydreb Posted January 28, 2021 Share Posted January 28, 2021 Just now, SpeedyWX said: Anyone have a sec for a newie question? Lots of comments about the initial thump, and it being cold powder, and referring to it as WAA. Which I understand is warm air advection. How does WARM air advection translate to cold powder? Thanks. Warm air rises, cold air sinks. When the warm air rises, it condenses into precipitation and since it’s moving into a cold air mass, the precip falls as snow. 5 Link to comment Share on other sites More sharing options...
mattskiva Posted January 28, 2021 Share Posted January 28, 2021 1 minute ago, psuhoffman said: @H2O You brought up very legit points last night. Before things get crazy let me explain why suppression is my bigger concern in this situation. Partly its about hedging bets. Given the confluence to our north, the high, and the cold as the wave approaches...I see virtually no way we get totally blanked with a cutter scenario. At the least we would get a nice WAA thump snow to dry slot. Maybe that isn't the 1-2 feet some are acting like we NEED for this not to bust...but I have 2 kids that are literally asking EVERYDAY when is it going to snow and to them there is almost no difference between 4" and 12". Frankly...20" is probably TOO much for them lol. I will still take it...they can wait for it to melt some! So my first consideration is "how do we avoid the total fail" where my ground ends up bare or with some pathetic amount that precludes sledding, snow fort building and the such. And IMO that is suppressed. Rooting against suppressed may mute the chances of the 2 foot solution some...but the math in my head I separate the boom (12"+) and the bust (less then 4") scenarios. Rooting for a more squashed wave might increase the boom but it increases the bust with this. So I would take a 50/10 (boom% v bust%) type split over a 70/40 type split. Also...frankly just looking at the h5 flow over the top of us and to the NE, I think the degree to which this can go north is muted. The flow is relaxing yes but its still pretty compressed to our northeast as the system enters the midwest. The further south guidance just "feels" more realistic. I can be wrong. I've been wrong. Just my gut. Lastly...the biggest risk, as I told Ji like 3 days ago...is a split. A suppression with the WAA wave then a slow primary that meanders northwest of us causing a late secondary that misses us northeast. But that is still "suppression" imo because the WAA wave is our bread and butter less likely to fail option. The CCB of a developing secondary coastal is ALWAYS a risky proposition and better to be taken as bonus not relied on. All that said...obviously I am human and biased and the fact I live on the northern tip of our geographic region needs to be taken into consideration. But even for places like Baltimore and Frederick and Winchester...I think my thoughts are valid. If I lived south of DC I would probably have a totally different preference for how I want this to evolve. Completely understandable. Also understand why @clskinsfan doesn't like a 2009-10 analog. That said, those of us out near Dulles strongly favor the suppressed solution . It's been five years since the last "big one" here -- and the setup is very similar to some of our historic storms. There is always some risk, but we are about 72 hours out and still have a coastal on the table -- it's been a while since we were this close. 4 Link to comment Share on other sites More sharing options...
packfan98 Posted January 28, 2021 Share Posted January 28, 2021 Here's where the RGEM ended up. I'm trying to avoid an ice storm down here in NC. Good luck to y'all up there in the powdery regions! 8 Link to comment Share on other sites More sharing options...
SpeedyWX Posted January 28, 2021 Share Posted January 28, 2021 Thanks jaydreb! Link to comment Share on other sites More sharing options...
ers-wxman1 Posted January 28, 2021 Share Posted January 28, 2021 Strong front end thump on the 12z icon but the primary is too strong and north which brings in warmer air and the dry slot. Coastal is too late. Waa thump is 3-5” for most. 3 1 Link to comment Share on other sites More sharing options...
Ephesians2 Posted January 28, 2021 Share Posted January 28, 2021 NAM/Euro/CMC are beautiful here (Lynchburg). 6-8"+ of snow falling with cold temperatures, maybe a brief period of sleet/freezing rain, and no rain to wash it away. Link to comment Share on other sites More sharing options...
psuhoffman Posted January 28, 2021 Share Posted January 28, 2021 ICON makes the jump to the secondary off the delmarva. Yes the process "begins" down in NC but its really just in its infancy stage and the coastal front baroclinic zone starts to amplify...it doesn't really take over as the primary circulation until at our latitude. That is no good. We need the Euro solution of a clean transfer to the outer banks. That simple. ICON solution would still be a nice front end WAA snow though. 1 Link to comment Share on other sites More sharing options...
MillvilleWx Posted January 28, 2021 Share Posted January 28, 2021 1 minute ago, SpeedyWX said: Anyone have a sec for a newie question? Lots of comments about the initial thump, and it being cold powder, and referring to it as WAA. Which I understand is warm air advection. How does WARM air advection translate to cold powder? Thanks. WAA is a translation to greater moisture feed. When you have warmer, less dense air riding into colder airmasses, you get a period of ascent that generates precip once it enters the colder thermal profile. Snowfall is physical mechanism generated by cooled water and enhanced through ascent (lifting mechanisms). WAA over a cold environment will lead to enhanced areas of lift within the boundary layer responsible for a majority of crystal growth in snow. You might have seen the term "Frontogenesis or Frontogen" mentioned in the forum at times. Those are favored areas of lift within certain boundary layers in the atmosphere. WAA regimes are typically located within the 850mb to 600mb layer aloft, which is favored with moisture transport. The better the lift between certain temperature profiles tends to generate better snow crystal structure (Dendrites) that accumulate more efficiently and are lighter in nature due to less water vapor condensing to make the snowflake. 3 7 Link to comment Share on other sites More sharing options...
caviman2201 Posted January 28, 2021 Share Posted January 28, 2021 11 minutes ago, psuhoffman said: I have 2 kids that are literally asking EVERYDAY when is it going to snow and to them there is almost no difference between 4" and 12". This hit home for me. I have a 3yo and 5yo and neither has really ever been able to go out and play in a good snow. If Sunday plays out like the models have been suggesting with all day snowfall, everything sticking due to prime climo, no sun angle worries, low temps... and it puts down 4-5" for my kids and I to go play in, I'm happy even if the coastal misses us. I hope the coastal CCB crushes us on Monday, of course, but I don't need it to be happy with this storm. My bar is low given the lack of snow lately so I've been putting it at a little under the ENS mean outputs, so a 4-6" storm is fine with me. As you and others have said... anyone upset over 4-6" from a Miller B in Nina doesn't know or is willfully ignoring our climo. 7 Link to comment Share on other sites More sharing options...
SpeedyWX Posted January 28, 2021 Share Posted January 28, 2021 Thanks Millville! 1 Link to comment Share on other sites More sharing options...
psuhoffman Posted January 28, 2021 Share Posted January 28, 2021 The 12k NAM on the last frame the surface low in NC is already developing a closed circulation. The next step we would want to see is the 850 low start to jump and reorganize along with the secondary. 9 Link to comment Share on other sites More sharing options...
Maestrobjwa Posted January 28, 2021 Share Posted January 28, 2021 7 minutes ago, psuhoffman said: ICON makes the jump to the secondary off the delmarva. Yes the process "begins" down in NC but its really just in its infancy stage and the coastal front baroclinic zone starts to amplify...it doesn't really take over as the primary circulation until at our latitude. That is no good. We need the Euro solution of a clean transfer to the outer banks. That simple. ICON solution would still be a nice front end WAA snow though. I do hope we can end this model stalemate today...one way or the other. What are the other late transfer models doing to make the primary go awry? Having it be too strong? Link to comment Share on other sites More sharing options...
MillvilleWx Posted January 28, 2021 Share Posted January 28, 2021 RGEM once again holding ground with the cold powder idea for the WAA snow on Sunday. Thermal profile is frigid through the whole front end, just like the NAM. Modest 850-700mb frontogen over NoVA and the 270 corridor. 6 1 Link to comment Share on other sites More sharing options...
MillvilleWx Posted January 28, 2021 Share Posted January 28, 2021 2 minutes ago, psuhoffman said: The 12k NAM on the last frame the surface low in NC is already developing a closed circulation. The next step we would want to see is the 850 low start to jump and reorganize along with the secondary. It's one of those times where I hope the NAM is on to the right idea for y'alls sake! 1 2 Link to comment Share on other sites More sharing options...
psuhoffman Posted January 28, 2021 Share Posted January 28, 2021 RGEM is even further south of the NAM but it is a little slower getting the secondary...but you can see it's going to jump to NC but it has not started to develop a closed circulation YET. But given the look at 84 the RGEM looks like it will go more the euro/nam route also. I was not looking at the last frame of the RGEM, hadn't updated DOH...now that I see it the RGEM is VERY similar to the NAM and Euro. Secondary is taking over near Greenville NC on the last frame and has begun to develop a closed circulation. That really is the key...the "worse" globals like the ICON and GFS that mostly miss us with the coastal ccb do so because they linger the primary longer and don't really begin the process of amplifying the secondary until it is off the VA capes. We need that process to start in NC. 10 3 Link to comment Share on other sites More sharing options...
AmericanWxFreak Posted January 28, 2021 Share Posted January 28, 2021 Looks fairly unchanged thru 48 Link to comment Share on other sites More sharing options...
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