snowfan Posted February 18, 2019 Share Posted February 18, 2019 9Z Wed.....18Z NAM has precip field expanding to the SW as it approaches DC. Snow has overspread the area at 12Z. 1 Link to comment Share on other sites More sharing options...
87storms Posted February 18, 2019 Share Posted February 18, 2019 looks like 7am start time with the thump occurring not too long after. temps in the upper 20s to start (estimating). Link to comment Share on other sites More sharing options...
nj2va Posted February 18, 2019 Share Posted February 18, 2019 2 minutes ago, snowfan said: 9Z Wed.....18Z NAM has precip field expanding to the SW as it approaches DC. Snow has overspread the area at 12Z. Surface temps really drop once precip arrives thanks to our low DPs. Go from 33 at 9z to 29 at 12z. Link to comment Share on other sites More sharing options...
87storms Posted February 18, 2019 Share Posted February 18, 2019 2 minutes ago, nj2va said: Surface temps really drop once precip arrives thanks to our low DPs. Go from 33 at 9z to 29 at 12z. i think this is gonna be a better run. high is in a better spot, too. marginal differences, but it does look a little better (for the city at least). Link to comment Share on other sites More sharing options...
nj2va Posted February 18, 2019 Share Posted February 18, 2019 At 18z Wednesday, 850 line is well south of EZF. 700 line is just NE of DC. 1 Link to comment Share on other sites More sharing options...
Chase Posted February 18, 2019 Share Posted February 18, 2019 8 Link to comment Share on other sites More sharing options...
wawarriors4 Posted February 18, 2019 Share Posted February 18, 2019 Just now, nj2va said: At 18z Wednesday, 850 line is well south of EZF. 700 line is just NE of DC. That would imply Sleet fest 2019 is well under way. To me, that may be the trickiest call, if/when we go from sleet to freezing rain or just sleet to rain. Probably depends on when 850 zero line comes North Link to comment Share on other sites More sharing options...
snowfan Posted February 18, 2019 Share Posted February 18, 2019 NAM throws the snow maxima well into the Ohio Valley and PA. Our area sees a general 2-4" snowfall before going to ice. Still icing at 0Z Wed at which time our total QPF is .75-1" for the 95 corridor. More N/W. Link to comment Share on other sites More sharing options...
WxUSAF Posted February 18, 2019 Share Posted February 18, 2019 Just now, wawarriors4 said: That would imply Sleet fest 2019 is well under way. To me, that may be the trickiest call, if/when we go from sleet to freezing rain or just sleet to rain. Probably depends on when 850 zero line comes North The warm layer is higher...about 700-750mb. And the warm nose usually moves north faster than progged in these situations which is doubly concerning when the euro is already the fastest with the warm push. IF it's right, it's probably only a little snow (1-2") for most of us south of the M/D line before a long sleet storm. 2 Link to comment Share on other sites More sharing options...
WxMan1 Posted February 18, 2019 Share Posted February 18, 2019 Dang that's a lot of sleet following the changeover for the cities/95 corridor around midday. As noted earlier -- 850s still below 0C, but layer near 700 climbs above 0C for this corridor by ~18Z 1 Link to comment Share on other sites More sharing options...
psuhoffman Posted February 18, 2019 Share Posted February 18, 2019 Just now, WxUSAF said: The warm layer is higher...about 700-750mb. And the warm nose usually moves north faster than progged in these situations which is doubly concerning when the euro is already the fastest with the warm push. IF it's right, it's probably only a little snow (1-2") for most of us south of the M/D line before a long sleet storm. Given the trends across guidance the last 24 hours I’m worried our chances of a heavy thump snow are slipping away and it’s becoming more of a messy icy mix threat. 1 1 Link to comment Share on other sites More sharing options...
snowfan Posted February 18, 2019 Share Posted February 18, 2019 Just now, WxUSAF said: The warm layer is higher...about 700-750mb. And the warm nose usually moves north faster than progged in these situations which is doubly concerning when the euro is already the fastest with the warm push. IF it's right, it's probably only a little snow (1-2") for most of us south of the M/D line before a long sleet storm. This is the outcome that I'm thinking is becoming more likely. We get a 1-3, maybe 2-4" front end snow, then we tack on a lot of sleet and wrapped it up with drizzle, freezing drizzle. Link to comment Share on other sites More sharing options...
ers-wxman1 Posted February 18, 2019 Share Posted February 18, 2019 18z NAM is a big hit. Solid snowfall area wide then an ice palace west of 95. Serious icing if this is correct. The CAD is very strong. 7 Link to comment Share on other sites More sharing options...
ers-wxman1 Posted February 18, 2019 Share Posted February 18, 2019 Parts of NOVA to I-81 are icing into Wednesday night/Thursday AM. 2 Link to comment Share on other sites More sharing options...
jaydreb Posted February 18, 2019 Share Posted February 18, 2019 Just now, psuhoffman said: Given the trends across guidance the last 24 hours I’m worried our chances of a heavy thump snow are slipping away and it’s becoming more of a messy icy mix threat. Just now, ers-wxman1 said: 18z NAM is a big hit. Solid snowfall area wide then an ice palace west of 95. Serious icing if this is correct. The CAD is very strong. Hmmm. Two good analysts with two different interpretations. Link to comment Share on other sites More sharing options...
nj2va Posted February 18, 2019 Share Posted February 18, 2019 3 minutes ago, 87storms said: i think this is gonna be a better run. high is in a better spot, too. marginal differences, but it does look a little better (for the city at least). Yeah, I like the run honestly. 0.45” QPF falls by 18z which should be all or mostly snow considering the 700 line is just barely NE of DC at 18z. We lose 850s ~21/22z. Lots of sleet in the afternoon it seems. I wish I was going to be in Deep Creek for this...looks like a high impact winter storm there...tons of precip out that way with very cold surface temps. Link to comment Share on other sites More sharing options...
Deck Pic Posted February 18, 2019 Share Posted February 18, 2019 4kNAM, DCA verbatim is snow until Noon-ish....then the 700mb warm nose intrudes... Link to comment Share on other sites More sharing options...
Kmlwx Posted February 18, 2019 Share Posted February 18, 2019 Just now, jaydreb said: Hmmm. Two good analysts with two different interpretations. Not really. psu just referenced a "heavy thump of snow" - you can still get a "solid snowfall" and then ice. They seem to agree to me. 1 Link to comment Share on other sites More sharing options...
osfan24 Posted February 18, 2019 Share Posted February 18, 2019 Agree with PSU that this is morphing into a sleet to freezing rain fest after just a few hours of snow. Link to comment Share on other sites More sharing options...
WxUSAF Posted February 18, 2019 Share Posted February 18, 2019 Just now, psuhoffman said: Given the trends across guidance the last 24 hours I’m worried our chances of a heavy thump snow are slipping away and it’s becoming more of a messy icy mix threat. Yeah, I guess it depends what you expect or define as a "heavy thump snow". I never held out much hope for the type of totals that LWX just put out as the "expected value". I've been in the 2-4"/3-6" range for MBY, less south, more north, sort of ballpark. But think there's more risk on the downside for much of the region due to the flip to sleet. That said, there still could be a small area that jackpots with a combo of lift/snow growth/precip totals. You're in a good spot for that as per usual. But either way, I think the snow comes in hot and heavy and probably accumulates close to 1"/hr for the time it falls. So that is a "heavy thump", just probably more like a 3-4 hour one than a 6-8 hour one. 3 Link to comment Share on other sites More sharing options...
ers-wxman1 Posted February 18, 2019 Share Posted February 18, 2019 NAM solidifies my thinking. Solid 2-4 in the cities, 4-8 west of 95 into NOVA, NC MD to I-81. Then sleet fest Wed afternoon to FZRA. Plain rain east of 95. The icing over the suburbs could be 0.25-0.50 on this. Scattered power outages. 14 Link to comment Share on other sites More sharing options...
WxMan1 Posted February 18, 2019 Share Posted February 18, 2019 Seems to me that for us in/near the cities or along the I95 corridor, we probably have a 4 maybe 5 hr window of accumulatingsnow, taking the NAM timing literally. 7 am through 11-noon. If we can average .50-1.0"/hr during that time, it would equate to 2-4" of snow before the sleet. I have a feeling here in northern AA we'll average 2-3" before the changeover. What happens next (how much accumulating sleet/freezing rain) is a bigger mystery IMO. Link to comment Share on other sites More sharing options...
nj2va Posted February 18, 2019 Share Posted February 18, 2019 ~.35” falls in DC as snow (assuming a noon-ish flip) on the 3k NAM so general 3-4” before sleet in the afternoon. Link to comment Share on other sites More sharing options...
snowfan Posted February 18, 2019 Share Posted February 18, 2019 3K NAM appears to have a slightly better orientation of the precip across the area. Thru 21Z Wed, there's .6 QPF for DC and the column is still supporting sleet with the warm layer surging NE at 800-700. By 0Z Wed, DC is still barely holding onto the surface with precip totals approaching .9". Bmore over 1" by then. Link to comment Share on other sites More sharing options...
BristowWx Posted February 18, 2019 Share Posted February 18, 2019 This was never gonna be a solid all snow event anyway. For most off us at least. But if you want a mixed frozen event that was rain on the models just days ago, it should be a decent showing. CAD still looks pretty good. All we can ask. Hi Bob wherever you are. 1 1 Link to comment Share on other sites More sharing options...
CAPE Posted February 18, 2019 Share Posted February 18, 2019 1 hour ago, WEATHER53 said: Need the high further west. That will be the key Not sure how much further west you want it, but overall recent guidance seems to at least have it positioned more towards our NE instead of it sliding more to the E/SE. Thats a good trend IMO, and looks to keep the cold in longer. Link to comment Share on other sites More sharing options...
psuhoffman Posted February 18, 2019 Share Posted February 18, 2019 4 minutes ago, ers-wxman1 said: 18z NAM is a big hit. Solid snowfall area wide then an ice palace west of 95. Serious icing if this is correct. The CAD is very strong. Maybe I’m looking at it wrong. I only see about 2-4” across most of our area before it flips to sleet. I don’t really see any big thumpy snow totals until up in central PA. Looks like BAD ice though. Some people are into that. Link to comment Share on other sites More sharing options...
MillvilleWx Posted February 18, 2019 Share Posted February 18, 2019 Both NAM's are showing an abundance of precip over the region. No shortage of QPF to work with. 3k showing over 2" along the 81 corridor. Could be very ugly anywhere west of 95 1 Link to comment Share on other sites More sharing options...
nj2va Posted February 18, 2019 Share Posted February 18, 2019 3k is a pretty crazy storm for Garrett (especially central/eastern parts of the county) and Frostburg/Cumberland. Over 2.5” QPF and temps never get above freezing. Link to comment Share on other sites More sharing options...
Wonderdog Posted February 18, 2019 Share Posted February 18, 2019 6 minutes ago, BristowWx said: This was never gonna be a solid all snow event anyway. For most off is at least. But if you want a mixed frozen event that was rain on the models just days ago, it should be a decent showing. CAD still looks pretty good. All we can ask. Hi Bob wherever you are. NWS has us in the 6-8 range brother. They're counting on something that most don't agree with. I figure that 5 inches may be our cap in PWC. More than enough to bring out the toy. This has the makings of a fun storm. Link to comment Share on other sites More sharing options...
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