WinterWxLuvr Posted February 28, 2015 Share Posted February 28, 2015 GFS is a decent event Link to comment Share on other sites More sharing options...
winterymix Posted February 28, 2015 Share Posted February 28, 2015 Cold air is tough to budge Anyone interested: please critique my amateur blend of GFS/NAM analysis for NVA/DC/central MD: Light snow 10 am to 1 pm. Unlikely that anyone will exceed 3 inches of snow east of the Blue Ridge and south of the MD Line. Sleet mixing from SE to NW from 1 pm to 3 pm. Sleet will be brief and not accumulate more than 1/4" to 1/3". Freezing rain mixing from SE to NW with all rain south of the Potomac River. All freezing rain to plain rain up to the Mason Dixon Line from 4 pm to 6 pm and then dry slot/drizzle from SW to NE. Freezing rain is unlikely to create major tree damage and unlikely to create major power outages. Road temperatures could be tricky and patchy. South and east of the cities should warm above freezing but some bridges and overpasses could retain below freezing temperatures throughout the afternoon even south and east of the cities due to sustained antecedent cold air mass at the surface. Well traveled road surfaces even north to the MD Line should be only wet/not freezing by sunset if treated. Smaller roads especially in valleys may have black ice due to the antecedent cold. Some cautious schools will be 2 hours late Monday morning. Link to comment Share on other sites More sharing options...
BTRWx Posted February 28, 2015 Share Posted February 28, 2015 Anyone interested: please critique my amateur blend of GFS/NAM analysis for NVA/DC/central MD: Light snow 10 am to 1 pm. Unlikely that anyone will exceed 3 inches of snow east of the Blue Ridge and south of the MD Line. Sleet mixing from SE to NW from 1 pm to 3 pm. Sleet will be brief and not accumulate more than 1/4" to 1/3". Freezing rain mixing from SE to NW with all rain south of the Potomac River. All freezing rain to plain rain up to the Mason Dixon Line from 4 pm to 6 pm and then dry slot/drizzle from SW to NE. Freezing rain is unlikely to create major tree damage and unlikely to create major power outages. Road temperatures could be tricky and patchy. South and east of the cities should warm above freezing but some bridges and overpasses could retain below freezing temperatures throughout the afternoon even south and east of the cities due to sustained antecedent cold air mass at the surface. Well traveled road surfaces even north to the MD Line should be only wet/not freezing by sunset if treated. Smaller roads especially in valleys may have black ice due to the antecedent cold. Some cautious schools will be 2 hours late Monday morning. Are you sure you want that? Link to comment Share on other sites More sharing options...
winterymix Posted February 28, 2015 Share Posted February 28, 2015 Are you sure you want that? Bring it. My hunch is that a bazillion similar events have trundled across our region and most behave in a similar fashion. This is not a "one-off" special. This looks well-modeled. The NAM, high rez NAM and GFS all seem to be converging with the thickness charts, start time of precip and tapering of precip. This is short lead time forecasting. Link to comment Share on other sites More sharing options...
StudentOfClimatology Posted February 28, 2015 Share Posted February 28, 2015 Currently 29.7/1..should have no problem radiating before the clouds move in. Dews are low, ground is plenty cold. Link to comment Share on other sites More sharing options...
ers-wxman1 Posted February 28, 2015 Share Posted February 28, 2015 Anyone interested: please critique my amateur blend of GFS/NAM analysis for NVA/DC/central MD: Light snow 10 am to 1 pm. Unlikely that anyone will exceed 3 inches of snow east of the Blue Ridge and south of the MD Line. Sleet mixing from SE to NW from 1 pm to 3 pm. Sleet will be brief and not accumulate more than 1/4" to 1/3". Freezing rain mixing from SE to NW with all rain south of the Potomac River. All freezing rain to plain rain up to the Mason Dixon Line from 4 pm to 6 pm and then dry slot/drizzle from SW to NE. Freezing rain is unlikely to create major tree damage and unlikely to create major power outages. Road temperatures could be tricky and patchy. South and east of the cities should warm above freezing but some bridges and overpasses could retain below freezing temperatures throughout the afternoon even south and east of the cities due to sustained antecedent cold air mass at the surface. Well traveled road surfaces even north to the MD Line should be only wet/not freezing by sunset if treated. Smaller roads especially in valleys may have black ice due to the antecedent cold. Some cautious schools will be 2 hours late Monday morning. Not bad. I think the colder air will hang in longer but March sun angle will play a role. Link to comment Share on other sites More sharing options...
mdsnowlover Posted February 28, 2015 Share Posted February 28, 2015 Bring it. My hunch is that a bazillion similar events have trundled across our region and most behave in a similar fashion. This is not a "one-off" special. This looks well-modeled. The NAM, high rez NAM and GFS all seem to be converging with the thickness charts, start time of precip and tapering of precip. This is short lead time forecasting. good summary thanks told my minister. Link to comment Share on other sites More sharing options...
ACFD FIREMAN Posted February 28, 2015 Share Posted February 28, 2015 Not bad. I think the colder air will hang in longer but March sun angle will play a role. I agree. Like last weekend this isn't our typical marginal late winter cold set-up. Link to comment Share on other sites More sharing options...
BTRWx Posted February 28, 2015 Share Posted February 28, 2015 Anyone interested: please critique my amateur blend of GFS/NAM analysis for NVA/DC/central MD: Light snow 10 am to 1 pm. Unlikely that anyone will exceed 3 inches of snow east of the Blue Ridge and south of the MD Line. Sleet mixing from SE to NW from 1 pm to 3 pm. Sleet will be brief and not accumulate more than 1/4" to 1/3". Freezing rain mixing from SE to NW with all rain south of the Potomac River. All freezing rain to plain rain up to the Mason Dixon Line from 4 pm to 6 pm and then dry slot/drizzle from SW to NE. Freezing rain is unlikely to create major tree damage and unlikely to create major power outages. Road temperatures could be tricky and patchy. South and east of the cities should warm above freezing but some bridges and overpasses could retain below freezing temperatures throughout the afternoon even south and east of the cities due to sustained antecedent cold air mass at the surface. Well traveled road surfaces even north to the MD Line should be only wet/not freezing by sunset if treated. Smaller roads especially in valleys may have black ice due to the antecedent cold. Some cautious schools will be 2 hours late Monday morning. I'm by far not the best person to do this, but since you requested some insight I'll share what I think. As an amateur myself, I don't like giving specific hours of the day for when I expect things to change. Instead I'd reference "mid-late morning" as an example. Those comments are what I mostly highlighted in red with timing details. I highlighted in green where I think you nailed the context of your text. I know it takes a lot of effort to put this stuff together and I think you're on the right track overall. My best suggestion would be not to be so specific/certain with most of the content. Thanks for sharing your ideas about tomorrow! Link to comment Share on other sites More sharing options...
Ian Posted February 28, 2015 Share Posted February 28, 2015 It's cold but it's not as cold as it was before the event last weekend going in. We came off that stretch of crazy days and into that. Freezing rain risk is poorly timed to make its biggest possible impact plus I doubt the highest QPF totals via earlier NAM etc end up right... if they did it's partly rate driven so it's not all going to accrete. No doubt there will be icy spots and some droopy pine trees if it comes together right. Spots that don't get much sun that are paved too.. notable for March, not too exciting tho.. expect for the stats padding snow (hopefully) that comes first at least. Link to comment Share on other sites More sharing options...
BTRWx Posted February 28, 2015 Share Posted February 28, 2015 It's cold but it's not as cold as it was before the event last weekend going in. We came off that stretch of crazy days and into that. Freezing rain risk is poorly timed to make its biggest possible impact plus I doubt the highest QPF totals via earlier NAM etc end up right... if they did it's partly rate driven so it's not all going to accrete. No doubt there will be icy spots and some droopy pine trees if it comes together right. Spots that don't get much sun that are paved too.. notable for March, not too exciting tho.. expect for the stats padding snow (hopefully) that comes first at least. Another difference to last weekend is we should have less *pure* liquid to deal with. Link to comment Share on other sites More sharing options...
WinterWxLuvr Posted February 28, 2015 Share Posted February 28, 2015 It's cold but it's not as cold as it was before the event last weekend going in. We came off that stretch of crazy days and into that. Freezing rain risk is poorly timed to make its biggest possible impact plus I doubt the highest QPF totals via earlier NAM etc end up right... if they did it's partly rate driven so it's not all going to accrete. No doubt there will be icy spots and some droopy pine trees if it comes together right. Spots that don't get much sun that are paved too.. notable for March, not too exciting tho.. expect for the stats padding snow (hopefully) that comes first at least. I agree but it looks to be plenty cold for this type of event...at least at the start. But time of day is a killer for this as far as travel impacts go. Trees and by extension power lines is another matter. Link to comment Share on other sites More sharing options...
BTRWx Posted February 28, 2015 Share Posted February 28, 2015 I agree but it looks to be plenty cold for this type of event...at least at the start. But time of day is a killer for this as far as travel impacts go. Trees and by extension power lines is another matter. Would less precip correlate with less waa? Link to comment Share on other sites More sharing options...
Swiscaster Posted February 28, 2015 Share Posted February 28, 2015 I am flying from HNL to IAD, scheduled to land around 1pm tomorrow. I havent been following the weather until now, but do you think this thing is significant enough to cause airport delays? Link to comment Share on other sites More sharing options...
BTRWx Posted February 28, 2015 Share Posted February 28, 2015 I am flying from HNL to IAD, scheduled to land around 1pm tomorrow. I havent been following the weather until now, but do you think this thing is significant enough to cause airport delays? very possible Link to comment Share on other sites More sharing options...
StudentOfClimatology Posted February 28, 2015 Share Posted February 28, 2015 Another difference here vs the last event (and I think this could be the breadwinner) is the LLJ is actually weaker w/ a more westerly component this time, vs last weekend where we had a 70kt LLJ just a few thousand feet off the ground..nothing like that now. Less kinematic forcing could make the cold air harder to erode. Link to comment Share on other sites More sharing options...
BTRWx Posted February 28, 2015 Share Posted February 28, 2015 Another difference here vs the last event is the LLJ is actually weaker w/ a more westerly component than the last one. Less kinematic forcing could make the cold air harder to erode. We had a 70kt LLJ just a few feet off the ground last weekend..nothing like that now. Wouldn't this explain the difference in lower precip rates expected? Link to comment Share on other sites More sharing options...
DDweatherman Posted February 28, 2015 Share Posted February 28, 2015 Wouldn't this explain the difference in lower precip rates expected?Actually that's correct, good call sir. Link to comment Share on other sites More sharing options...
ers-wxman1 Posted February 28, 2015 Share Posted February 28, 2015 I am flying from HNL to IAD, scheduled to land around 1pm tomorrow. I havent been following the weather until now, but do you think this thing is significant enough to cause airport delays?If the precip comes in early enough...yes Link to comment Share on other sites More sharing options...
Joshfsu123 Posted February 28, 2015 Share Posted February 28, 2015 So I have a 5k/10k run in DC tomorrow AM? Any opinions on if there is any chance of it happening? Looks cold and icy. Link to comment Share on other sites More sharing options...
StudentOfClimatology Posted February 28, 2015 Share Posted February 28, 2015 Wouldn't this explain the difference in lower precip rates expected? This airmass is also more "wedged in" w/ the high closer to us (if the crazy high pressures today weren't evidence enough). I believe everyone N/W of the fall line & east of the Blue Ridge stays below freezing for the entirety of the event, or close to it. Link to comment Share on other sites More sharing options...
BTRWx Posted February 28, 2015 Share Posted February 28, 2015 So I have a 5k/10k run in DC tomorrow AM? Any opinions on if there is any chance of it happening? Looks cold and icy. tough one! Link to comment Share on other sites More sharing options...
ers-wxman1 Posted February 28, 2015 Share Posted February 28, 2015 So I have a 5k/10k run in DC tomorrow AM? Any opinions on if there is any chance of it happening? Looks cold and icy. I don't know if I would want it to happen ;-) Link to comment Share on other sites More sharing options...
AvantHiatus Posted February 28, 2015 Share Posted February 28, 2015 This airmass is also more "wedged in" w/ the high closer to us (if the crazy high pressures today weren't evidence enough). I believe everyone N/W of the fall line & east of the Blue Ridge stays below freezing for the entirety of the event, or close to it. My weather station beeped at me this morning, just realized it was the highest pressure on record. Things are getting pretty fooked up eh SOC? Link to comment Share on other sites More sharing options...
ers-wxman1 Posted February 28, 2015 Share Posted February 28, 2015 It's going to be tough to get above freezing tomorrow especially west of 95 Link to comment Share on other sites More sharing options...
Eskimo Joe Posted February 28, 2015 Share Posted February 28, 2015 It's going to be tough to get above freezing tomorrow especially west of 95 Still, going to need heavy rates to overcome the sun angle. Link to comment Share on other sites More sharing options...
BristowWx Posted February 28, 2015 Share Posted February 28, 2015 Still, going to need heavy rates to overcome the sun angle. Heavy rates of what? Rain? That usually results in less ice accretion. Link to comment Share on other sites More sharing options...
Ian Posted February 28, 2015 Share Posted February 28, 2015 I agree but it looks to be plenty cold for this type of event...at least at the start. But time of day is a killer for this as far as travel impacts go. Trees and by extension power lines is another matter. it is.. plenty cold. how much snow/sleet is put down and not removed first may be a factor too. it's definitely an event of note for this time of year if it comes together as it appears. Link to comment Share on other sites More sharing options...
snowfan Posted February 28, 2015 Share Posted February 28, 2015 I'll hope for front end snow. Icing doesn't work out well imby Link to comment Share on other sites More sharing options...
mitchnick Posted February 28, 2015 Share Posted February 28, 2015 it is.. plenty cold. how much snow/sleet is put down and not removed first may be a factor too. it's definitely an event of note for this time of year if it comes together as it appears. a key player http://weather.unisys.com/surface/sfc_con.php?image=de&inv=0&t=cur tonight's soundings will be interesting the reason why the south had snow this week were their crazy dp's aloft and down low which still allowed them to get decent snow after reaching mid-40's during the day Thursday night ROA had a dp is -48.5C at the 850 level as 1 example now, it ain't that dry tonight, but I'm sure soundings will show some pretty dry air down the east coast Link to comment Share on other sites More sharing options...
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