T. August Posted January 12, 2019 Share Posted January 12, 2019 33/18 HdG Link to comment Share on other sites More sharing options...
PWC Split Posted January 12, 2019 Share Posted January 12, 2019 33/19 in Haymarket. Birds were singing loudly this morning. Link to comment Share on other sites More sharing options...
clskinsfan Posted January 12, 2019 Share Posted January 12, 2019 3 minutes ago, BTRWx's Thanks Giving said: Someone please turn storm mode back on. This is an obs thread. No storm mode. Link to comment Share on other sites More sharing options...
yoda Posted January 12, 2019 Share Posted January 12, 2019 Could someone explain what CSI banding is real quick? Its mentioned in the LWX AFD... is that like thundersnow? Link to comment Share on other sites More sharing options...
mappy Posted January 12, 2019 Share Posted January 12, 2019 That Accu map is going to bust pretty hard around the M/D line, it would seem. 1-3 inches? It’s not awful, 3-5” along the line I think is a good call. Best stuff is gonna stay south unless a deathband sets up somewhere Link to comment Share on other sites More sharing options...
jayyy Posted January 12, 2019 Share Posted January 12, 2019 Dark sky app clearly uses the NAM output lmao. Shows 7-11+ for my current location at work in Columbia. Nuts! still think we see 4-8” area wide. 4” north of Baltimore, 6” between Baltimore and dc and 8+ Possible dc and south. Link to comment Share on other sites More sharing options...
clskinsfan Posted January 12, 2019 Share Posted January 12, 2019 Just now, yoda said: Could someone explain what CSI banding is real quick? Its mentioned in the LWX AFD... is that like thundersnow? https://www.weather5280.com/blog/2017/01/05/what-is-conditional-symmetric-instability-csi/ Link to comment Share on other sites More sharing options...
Bob Chill Posted January 12, 2019 Author Share Posted January 12, 2019 Just now, mappy said: It’s not awful, 3-5” along the line I think is a good call. Best stuff is gonna stay south unless a deathband sets up somewhere . Enjoy your 6"+ of cold powder Link to comment Share on other sites More sharing options...
DSF Posted January 12, 2019 Share Posted January 12, 2019 11 minutes ago, BristowWx said: He's a 400 year old Jedi for heavens sake. When 900 years old you reach, look as good, you will not. Link to comment Share on other sites More sharing options...
wawarriors4 Posted January 12, 2019 Share Posted January 12, 2019 Looks like LWX updated their snowfall may at 11:21 https://www.weather.gov/lwx/winter Link to comment Share on other sites More sharing options...
jayyy Posted January 12, 2019 Share Posted January 12, 2019 I think central MD is in a good spot. South enough for high qpf totals, north enough for good ratios. Should help Howard and Montgomery county get to DC’s totals. Link to comment Share on other sites More sharing options...
Snowman. Posted January 12, 2019 Share Posted January 12, 2019 Updated LWX snowfall total map Link to comment Share on other sites More sharing options...
Beachin Posted January 12, 2019 Share Posted January 12, 2019 Lwx update is rather certain a WSW will be incoming for the Baltimore metro Link to comment Share on other sites More sharing options...
PivotPoint Posted January 12, 2019 Share Posted January 12, 2019 Just now, Snowman. said: Updated LWX snowfall total map 8-12 creeping into Fairfax. Biggest run of Nam’s Life happen in 3 hours lol Link to comment Share on other sites More sharing options...
mappy Posted January 12, 2019 Share Posted January 12, 2019 Enjoy your 6"+ of cold powder Ha! You too friend Link to comment Share on other sites More sharing options...
BrianW Posted January 12, 2019 Share Posted January 12, 2019 I am in DC for a wedding tonight and have a jetblue flight back to Hartford from Reagan airport at 5 pm tomorrow. Thoughts on that flight happening? We were planning on taking a cab or uber to the airport. Looking forward to the storm though. Its been pretty much snowless back home in CT. Link to comment Share on other sites More sharing options...
SomeguyfromTakomaPark Posted January 12, 2019 Share Posted January 12, 2019 Hard to tell on meteocenter maps on mobile but I think UK improved a little with the Sunday night action. Link to comment Share on other sites More sharing options...
heavy_wx Posted January 12, 2019 Share Posted January 12, 2019 Just for fun, here is a good example of mesoscale banding indicated by some diagnostics of the 12z NAM. The 750 mb heights (black), frontogenesis, and saturation equivalent potential vorticity (SEPV) are plotted above. SEPV is a measure of the stability of air parcels to slantwise and/or vertical displacements in a saturated environment. Regions of negative SEPV have been associated with mesoscale precipitation bands in winter storms. You can see that there is a band of negative SEPV from east of the Delmarva to northern MD, to the north of the closed 750-mb height contour. There is also enhanced 750-mb frontogenesis in this region, associated with a thermally direct circulation (i.e., warm air rising to the south, cold air sinking north). This circulation provides lift, and in the aforementioned environment of conditional stability, leads to enhanced vertical motion within the general synoptic ascent. An important thing to note with these diagonistics is that these circulations and regions of conditional instability occur within layers of the atmosphere, and are often sloped. For example, here is the same plot but for 850 mb: You can see here that the main region of conditional instability and enhanced frontogenesis is displaced to the south over central VA and SE MD. These two levels are different horizontal slices through the same circulation; in this case the circulation is sloped to the north with height. Where this circulation intersects the dendritic growth zone (DGZ) is often where the most intense banded precipitation occurs, due to the region having the most efficient ice crystal growth and aggregation. For more information, this is one good resource: http://cstar.cestm.albany.edu/CAP_Projects/Project6/Mesoscale_Structure/seminar (M. Greenstein).ppt Link to comment Share on other sites More sharing options...
BlizzardNole Posted January 12, 2019 Share Posted January 12, 2019 If Charlottesville gets 12" they will be sitting at 24" for the winter. That's nuts! 33 and overcast. Link to comment Share on other sites More sharing options...
Beachin Posted January 12, 2019 Share Posted January 12, 2019 3 minutes ago, DCTeacherman said: Hard to tell on meteocenter maps on mobile but I think UK improved a little with the Sunday night action. Definitely improved comparing side by side Link to comment Share on other sites More sharing options...
Lake Frederick Mike Posted January 12, 2019 Share Posted January 12, 2019 Few stray flurries at the moment, 28/19 and 30.53 60 miles west of DC, 8 miles east of Front Royal. Link to comment Share on other sites More sharing options...
Fozz Posted January 12, 2019 Share Posted January 12, 2019 9 minutes ago, Snowman. said: Updated LWX snowfall total map Hmmmm.... looks like they're hinting at expanding the warnings into Baltimore. Also it seems like barring a big north jump, @NorthArlington101 made the right move by driving to Charlottesville. Link to comment Share on other sites More sharing options...
Beachin Posted January 12, 2019 Share Posted January 12, 2019 HRRR now has light snow in the baltimore area by 20z Link to comment Share on other sites More sharing options...
SomeguyfromTakomaPark Posted January 12, 2019 Share Posted January 12, 2019 2 minutes ago, Beachin said: Definitely improved comparing side by side Adding up the lower bounds of the precipitation 6 hr maps I get about 0.5 inches for DC, so it should be a good run. Link to comment Share on other sites More sharing options...
clskinsfan Posted January 12, 2019 Share Posted January 12, 2019 Flakes reported just to my west and south. It is almost go time here. Link to comment Share on other sites More sharing options...
EastCoast NPZ Posted January 12, 2019 Share Posted January 12, 2019 Noticeable thickening of cloud deck the last 15 min. Wont be long. Gonna climb the roof and get a look west to North Mountain to see when it crosses the range! Link to comment Share on other sites More sharing options...
Beachin Posted January 12, 2019 Share Posted January 12, 2019 Just now, DCTeacherman said: Adding up the lower bounds of the precipitation 6 hr maps I get about 0.5 inches for DC, so it should be a good run. Looks like DC gets near .6-.7 and Bal gets .4-.5 about a .1 or .2 increase for both cities. Link to comment Share on other sites More sharing options...
MillvilleWx Posted January 12, 2019 Share Posted January 12, 2019 5 minutes ago, heavy_wx said: Just for fun, here is a good example of mesoscale banding indicated by some diagnostics of the 12z NAM. The 750 mb heights (black), frontogenesis, and saturation equivalent potential vorticity (SEPV) are plotted above. SEPV is a measure of the stability of air parcels to slantwise and/or vertical displacements in a saturated environment. Regions of negative SEPV have been associated with mesoscale precipitation bands in winter storms. You can see that there is a band of negative SEPV from east of the Delmarva to northern MD, to the north of the closed 750-mb height contour. There is also enhanced 750-mb frontogenesis in this region, associated with a thermally direct circulation (i.e., warm air rising to the south, cold air sinking north). This circulation provides lift, and in the aforementioned environment of conditional stability, leads to enhanced vertical motion within the general synoptic ascent. An important thing to note with these diagonistics is that these circulations and regions of conditional instability occur within layers of the atmosphere, and are often sloped. For example, here is the same plot but for 850 mb: You can see here that the main region of conditional instability and enhanced frontogenesis is displaced to the south over central VA and SE MD. These two levels are different horizontal slices through the same circulation; in this case the circulation is sloped to the north with height. Where this circulation intersects the dendritic growth zone (DGZ) is often where the most intense banded precipitation occurs, due to the region having the most efficient ice crystal growth and aggregation. For more information, this is one good resource: http://cstar.cestm.albany.edu/CAP_Projects/Project6/Mesoscale_Structure/seminar (M. Greenstein).ppt I've been waiting for you to chime in Heavy. Good to hear from you on this one. Looks like your area will be getting the goods down there in Laurel Link to comment Share on other sites More sharing options...
nj2va Posted January 12, 2019 Share Posted January 12, 2019 24/18 with first few flurries in McHenry. Link to comment Share on other sites More sharing options...
pogoism9 Posted January 12, 2019 Share Posted January 12, 2019 EZF is quiet currently, but certainly getting colder. Bring it on! Link to comment Share on other sites More sharing options...
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