Thunder Road Posted January 18, 2011 Share Posted January 18, 2011 Yes i am 5 miles NW of Baltimore City and it is snowing a little heavier than light right now. It is also alot colder then i thought it would be it is 25.7 right now. That's very interesting. Any mets feel like chiming in? Even the latest HRRR only has precip as far north as the lower Potomac at 01z: Link to comment Share on other sites More sharing options...
Feb Posted January 18, 2011 Share Posted January 18, 2011 7:00pm Monday update: I really think some forecasters are underplaying this event. It's really a classic set up for an icy mess. Temperatures didn't hardly rise today...a sign of the strong cold air damming in place across the region. Also, dew points remain in the singles and teens early this evening, so the air will cool a bit more when precipitation arrives. Still looks like light snow will develop by mid-evening, and become steady before midnight. An inch or two of snow is possible, but the bigger concern is ice build-up on trees, powerlines, and untreated roads...later tonight into midday Tuesday. A 1/4" of ice (perhaps more in spots) is possible by mid-morning Tuesday, as temps only slowly rise towards 32 degrees. The steady precip will likely end around Noon, and so mos--or all--of the event will occur with below freezing temps. Thus, my concern for a pretty significant event the next 18 hours...one that I think deserves a Winter Storm Warning from the NWS (we are only in a lesser "Advisory", though). http://snowball.mill...Discussion.html Interesting be curios how this all plays out tomorrow. Just read that on the Millersville site. Currently 24 degrees in Lancaster with a dew point of 12. It looks to get real ugly over night. Link to comment Share on other sites More sharing options...
Boreal Posted January 18, 2011 Share Posted January 18, 2011 Bangor,PA. 20.5°, slowly receding. 7:45 pm. Link to comment Share on other sites More sharing options...
famartin Posted January 18, 2011 Share Posted January 18, 2011 That's very interesting. Any mets feel like chiming in? Even the latest HRRR only has precip as far north as the lower Potomac at 01z: Typical models and their inability to accurately forecast the onset of warm advection precip... Its not uncommon for it to start earlier than progged. Link to comment Share on other sites More sharing options...
hazwoper Posted January 18, 2011 Share Posted January 18, 2011 Those saying media underplaying, I disagree. Once the mid levels go above freezing we'll see a period of IP, but when it goes over to ZR, I suspect a lot of places won't have as big of an issue with ice accum. Even with surface temps upper 20s to low 30s, the latent heat exchange from heavy rain fall will mean less accum ice then many here are thinking. Any mets care to comment? Link to comment Share on other sites More sharing options...
Thunder Road Posted January 18, 2011 Share Posted January 18, 2011 Typical models and their inability to accurately forecast the onset of warm advection precip... Its not uncommon for it to start earlier than progged. I've been hearing about that possibility all day, but I didn't think it would start 4 hours early. I was thinking more like 1-2 hours. Now let's see if it actually holds together... Link to comment Share on other sites More sharing options...
Ericjcrash Posted January 18, 2011 Share Posted January 18, 2011 I've been hearing about that possibility all day, but I didn't think it would start 4 hours early. I was thinking more like 1-2 hours. Now let's see if it actually holds together... Its already 8, not that early if you ask me. Link to comment Share on other sites More sharing options...
Voyager Posted January 18, 2011 Share Posted January 18, 2011 My temp has dropped slightly. I maxed out at 25.2 this afternoon, now I'm down to 23.9. Not far off of my temps. I maxed at 25.2 as well, and am down to 23.0 at the moment. Link to comment Share on other sites More sharing options...
Thunder Road Posted January 18, 2011 Share Posted January 18, 2011 Those saying media underplaying, I disagree. Once the mid levels go above freezing we'll see a period of IP, but when it goes over to ZR, I suspect a lot of places won't have as big of an issue with ice accum. Even with surface temps upper 20s to low 30s, the latent heat exchange from heavy rain fall will mean less accum ice then many here are thinking. Any mets care to comment? I'm not a met (but I did stay at a Holiday Inn Express last night!) but using my trusty ol' HRRR, I see rather light precip falling around 08z (3am). Also by this point, 850's and 925's have cleared the PA TPK, so it would be ZR already. Link to comment Share on other sites More sharing options...
Thunder Road Posted January 18, 2011 Share Posted January 18, 2011 Its already 8, not that early if you ask me. Yes but it's still earlier than the meso models had it starting. The NAM has consistently only had ~0.05" before 06z IMBY. If it started snowing at 9pm, we would probably get more than 0.05" in 4 hours. Link to comment Share on other sites More sharing options...
iceman56 Posted January 18, 2011 Share Posted January 18, 2011 22.3 and just cloudy here in NW Chester County. Link to comment Share on other sites More sharing options...
The Iceman Posted January 18, 2011 Share Posted January 18, 2011 Just read that on the Millersville site. Currently 24 degrees in Lancaster with a dew point of 12. It looks to get real ugly over night. Feb, I also think that it could get real nasty tonight into tomorrow around here. Like Horst said earlier, the temps didn't budge at all today...once precip starts we should also drop a few degrees. in events in the past when temps are this low and the majority of precip falls over night, they typically don't rise as fast and we tend to last longer on the frozen side...i'm thinking we see a real messy morning commute tomorrow. Link to comment Share on other sites More sharing options...
famartin Posted January 18, 2011 Share Posted January 18, 2011 I've been hearing about that possibility all day, but I didn't think it would start 4 hours early. I was thinking more like 1-2 hours. Now let's see if it actually holds together... Eh... I know in a later post you said you were following the Meso's... but the GFS and NAM have both been saying that it would start around TTN between 10PM and midnight. Link to comment Share on other sites More sharing options...
RowanBrandon Posted January 18, 2011 Share Posted January 18, 2011 Light snow has begun. Link to comment Share on other sites More sharing options...
Ericjcrash Posted January 18, 2011 Share Posted January 18, 2011 Eh... I know in a later post you said you were following the Meso's... but the GFS and NAM have both been saying that it would start around TTN between 10PM and midnight. Yeah, just slightly ahead of modeling which is the norm IMO. Link to comment Share on other sites More sharing options...
NortheastPAWx Posted January 18, 2011 Share Posted January 18, 2011 16.2*F, DP 8*F. Link to comment Share on other sites More sharing options...
chubbs Posted January 18, 2011 Share Posted January 18, 2011 Light snow just started. 24F Link to comment Share on other sites More sharing options...
famartin Posted January 18, 2011 Share Posted January 18, 2011 FWIW, the model tradition of warming 850's too slowly may also be in play... the 12Z GFS appears to be about 2C too cold with 850 temps at IAD and WAL, compared to the actual soundings from 0Z... Link to comment Share on other sites More sharing options...
famartin Posted January 18, 2011 Share Posted January 18, 2011 Based on latest obs it looks like the snow/non-snow line stretches from about DCA to DOV... Link to comment Share on other sites More sharing options...
tombo82685 Posted January 18, 2011 Share Posted January 18, 2011 you can tell we are dealing with an eroding airmass. Not much virga at all. Actually would of been nice to see some virga. Link to comment Share on other sites More sharing options...
Quakertown needs snow Posted January 18, 2011 Share Posted January 18, 2011 21.4 Link to comment Share on other sites More sharing options...
FPizz Posted January 18, 2011 Share Posted January 18, 2011 Temp has risen 1.2 deg the last hour here. 26.4 now. Link to comment Share on other sites More sharing options...
ChescoWx Posted January 18, 2011 Share Posted January 18, 2011 I would suspect the change from snow to get here much quicker then my wxsim forecast...so lower snow but i expect the zr to be the big problem for the AM here in the philly burbs Link to comment Share on other sites More sharing options...
SnowGoose69 Posted January 18, 2011 Share Posted January 18, 2011 you can tell we are dealing with an eroding airmass. Not much virga at all. Actually would of been nice to see some virga. There usually is not alot of virga with these as you get closer to the coastal areas because the easterly flow ahead of it often gives you enough saturation...virga could kill you to an extent in an event like this since you are strapped for time as far as getting frozen precipitation even though it could indicate as you say you have a fresher cold air mass. Link to comment Share on other sites More sharing options...
56er Posted January 18, 2011 Share Posted January 18, 2011 Light snow/30 degrees/minor coating. Link to comment Share on other sites More sharing options...
nzucker Posted January 18, 2011 Share Posted January 18, 2011 There usually is not alot of virga with these as you get closer to the coastal areas because the easterly flow ahead of it often gives you enough saturation...virga could kill you to an extent in an event like this since you are strapped for time as far as getting frozen precipitation even though it could indicate as you say you have a fresher cold air mass. I don't want too much virga as we need to get the snow in before 850s warm. Also, the airmass is plenty cold up here, I'm at 23.4/12 so should be seeing a good bit of evaporational cooling when the snow arrives. Link to comment Share on other sites More sharing options...
rygar Posted January 18, 2011 Share Posted January 18, 2011 20.6 here, dp 10. Hoping for 3-4 with minimal ice Link to comment Share on other sites More sharing options...
ShoreWXgal Posted January 18, 2011 Share Posted January 18, 2011 Light snow... Temp 34/30 Link to comment Share on other sites More sharing options...
dizzy9479 Posted January 18, 2011 Share Posted January 18, 2011 Light snow has commenced here in Williamstown, NJ Link to comment Share on other sites More sharing options...
SmokeEater Posted January 18, 2011 Share Posted January 18, 2011 Light snow started here about 20 minutes ago. 28/14 Link to comment Share on other sites More sharing options...
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