yoda Posted August 21, 2017 Share Posted August 21, 2017 BULLETIN - IMMEDIATE BROADCAST REQUESTED Severe Thunderstorm Warning National Weather Service Baltimore MD/Washington DC 237 PM EDT MON AUG 21 2017 The National Weather Service in Sterling Virginia has issued a * Severe Thunderstorm Warning for... North central Stafford County in northern Virginia... Southeastern Prince William County in northern Virginia... * Until 330 PM EDT * At 237 PM EDT, a severe thunderstorm was located 8 miles west of Dale City, moving east at 10 mph. HAZARD...60 mph wind gusts and quarter size hail. SOURCE...Radar indicated. IMPACT...Damaging winds will cause some trees and large branches to fall. This could injure those outdoors, as well as damage homes and vehicles. Roadways may become blocked by downed trees. Localized power outages are possible. Unsecured light objects may become projectiles. * Locations impacted include... Dale City, Woodbridge, Lake Ridge, Montclair, Triangle, Dumfries, Cherry Hill, Independent Hill, Nokesville, Occoquan and Aden. Link to comment Share on other sites More sharing options...
yoda Posted August 21, 2017 Share Posted August 21, 2017 Am I reading it wrong or is that some rotation just SW of Dale City? Link to comment Share on other sites More sharing options...
Eskimo Joe Posted August 21, 2017 Share Posted August 21, 2017 1 minute ago, yoda said: Am I reading it wrong or is that some rotation just SW of Dale City? I'm seeing the same thing. There's a pretty solid amount of CAPE and shear there...plus that's the La Plata Tornado Zone™ Link to comment Share on other sites More sharing options...
yoda Posted August 21, 2017 Share Posted August 21, 2017 2 minutes ago, Eskimo Joe said: I'm seeing the same thing. There's a pretty solid amount of CAPE and shear there...plus that's the La Plata Tornado Zone™ Decent VIL per radarscope as well Link to comment Share on other sites More sharing options...
Eskimo Joe Posted August 21, 2017 Share Posted August 21, 2017 Pity Meso: http://www.spc.noaa.gov/products/md/2017/md1542.html Link to comment Share on other sites More sharing options...
yoda Posted August 21, 2017 Share Posted August 21, 2017 1 minute ago, Eskimo Joe said: Pity Meso: http://www.spc.noaa.gov/products/md/2017/md1542.html Won't see this everyday 12Z regional soundings sampled poor mid-level lapse rates, somewhat tempering convective vigor. Additionally, visible satellite and radar data suggest a loss of insolation from the ongoing solar eclipse is stunting destabilization of the boundary layer. Link to comment Share on other sites More sharing options...
Eskimo Joe Posted August 21, 2017 Share Posted August 21, 2017 Just now, yoda said: Won't see this everyday That's how we roll in the Mid Atlantic...whether it's an eclipse, CAD, shear or water logged parcels we're usually a fail. Link to comment Share on other sites More sharing options...
mattie g Posted August 21, 2017 Share Posted August 21, 2017 I wonder if the outflow from the Prince William County cell(s) will help fire something a little farther west. Link to comment Share on other sites More sharing options...
Eskimo Joe Posted August 21, 2017 Share Posted August 21, 2017 Nice little hook trying to develop just north of Dundalk? Link to comment Share on other sites More sharing options...
North Balti Zen Posted August 21, 2017 Share Posted August 21, 2017 2 minutes ago, Eskimo Joe said: Nice little hook trying to develop just north of Dundalk? I look east toward Dundalk from my building (20th floor)...maybe. There's definitely a lowered cloud deck between here and there. Link to comment Share on other sites More sharing options...
Eskimo Joe Posted August 21, 2017 Share Posted August 21, 2017 3 minutes ago, North Balti Zen said: I look east toward Dundalk from my building (20th floor)...maybe. There's definitely a lowered cloud deck between here and there. Heh, I've seen LWX drops TORs for less. That refreshed scan is pretty nice. Link to comment Share on other sites More sharing options...
North Balti Zen Posted August 21, 2017 Share Posted August 21, 2017 Pretty good lightning show over that way too. Link to comment Share on other sites More sharing options...
Eskimo Joe Posted August 21, 2017 Share Posted August 21, 2017 1 minute ago, North Balti Zen said: Pretty good lightning show over that way too. Flash Flood Warning now too: Quote The National Weather Service in Sterling Virginia has issued a * Flash Flood Warning for... East central Baltimore City in northern Maryland... Southeastern Baltimore County in northern Maryland... * Until 730 PM EDT * At 330 PM EDT, Doppler radar indicated thunderstorms producing heavy rain across the area. Up to two inches of rain have already fallen. Flash flooding is expected to begin shortly. * Some locations that may experience flooding include... Baltimore, Middle River, North Point State Park, Sparrows Point, Back River, Millers Island, Dundalk, Essex, Rosedale, Rossville, Bowleys Quarters, Edgemere, Fort Howard, Chase, Eastpoint, Martin State Airport and Turners Station. Link to comment Share on other sites More sharing options...
North Balti Zen Posted August 21, 2017 Share Posted August 21, 2017 That is a legit storm to watch from this vantage point for sure. Hopkins Bayview is literally due east on a line from my office window, the storm is framed from there to the south from my vantage point. Just saw five successive cloud to ground lightning strikes across that panorama. Link to comment Share on other sites More sharing options...
yoda Posted August 22, 2017 Share Posted August 22, 2017 Possible tornado threat tomorrow evening? 00z NAM soundings don't have huge hodographs, but there's enough there (200+ 1km SRH) for a tor threat IMO between 21z and 03z across the region Link to comment Share on other sites More sharing options...
Ellinwood Posted August 22, 2017 Share Posted August 22, 2017 4 hours ago, yoda said: Possible tornado threat tomorrow evening? 00z NAM soundings don't have huge hodographs, but there's enough there (200+ 1km SRH) for a tor threat IMO between 21z and 03z across the region I don't think we'll get storms to pop south of 40N in that time frame. I did however notice the same thing further north into eastern PA. Even southeastern PA could have initiation problems, though. Link to comment Share on other sites More sharing options...
high risk Posted August 22, 2017 Share Posted August 22, 2017 5 hours ago, Ellinwood said: I don't think we'll get storms to pop south of 40N in that time frame. I did however notice the same thing further north into eastern PA. Even southeastern PA could have initiation problems, though. yeah, the shear is respectable later today, but the mid-level temps are warm, and the forecast soundings have that tall, skinny cape which is never good for parcel accelerations. The HRRR parallel, however, does pop a few decent looking cells in northern MD just after dark. Link to comment Share on other sites More sharing options...
yoda Posted August 22, 2017 Share Posted August 22, 2017 12z 3km NAM gets some storms into the region after dark... but they aren't as robust as they were in the NW portion of the LWX CWA Link to comment Share on other sites More sharing options...
yoda Posted August 22, 2017 Share Posted August 22, 2017 Hmmm Area Forecast Discussion National Weather Service Baltimore MD/Washington DC 225 PM EDT Tue Aug 22 2017 .NEAR TERM /TONIGHT/... Temperatures in the lower 90s and dewpoints in the low 70s have led to another day with CAPEs of 1000-2000. It is a different synoptic situation from yesterday as we have our eyes on a front/line of storms stretching from Ontario to southern IL. Watches are in effect to our west and north. Aside from any isolated cells that fire ahead of the line the main possibility of convection looks to be from around 9 pm over the mountains to after midnight by the Bay. Models have consistent in weakening the cells once these move east of the Blue Ridge. Yes heating will be over/CAPE will be diminishing but think given the amount of energy in the atmosphere still believe severe storms could be possible through midnight. Link to comment Share on other sites More sharing options...
high risk Posted August 22, 2017 Share Posted August 22, 2017 New Mesoscale Discussion from SPC shows the certain issuance of a box to our north shortly, but the discussion area includes the northern most row of counties in Maryland. I would think that the southern boundary of the new watch would be the Mason-Dixon line, but it will be interesting to see if they go further south (although I'm not sold on a svr threat south of the PA/MD border.) Link to comment Share on other sites More sharing options...
high risk Posted September 1, 2017 Share Posted September 1, 2017 I mentioned this in the regular September discussion last night, but it belongs here too: [ But the evening hours (Saturday) may have sneaky potential, especially in southern MD. A warm front will be lifting into the area, and the NAM nest has a convective line along the cold front. Enough low-level warm air could get into southern MD to make things interesting, given the decent wind field that will be in place. ] SPC does have a marginal risk not too far southeast of our area and some interesting discussion. Link to comment Share on other sites More sharing options...
nw baltimore wx Posted September 2, 2017 Share Posted September 2, 2017 13 hours ago, high risk said: I mentioned this in the regular September discussion last night, but it belongs here too: [ But the evening hours (Saturday) may have sneaky potential, especially in southern MD. A warm front will be lifting into the area, and the NAM nest has a convective line along the cold front. Enough low-level warm air could get into southern MD to make things interesting, given the decent wind field that will be in place. ] SPC does have a marginal risk not too far southeast of our area and some interesting discussion. Is this one of those rare situations where we could get those cool inversion thunder rumbles? Link to comment Share on other sites More sharing options...
high risk Posted September 2, 2017 Share Posted September 2, 2017 3 minutes ago, nw baltimore wx said: Is this one of those rare situations where we could get those cool inversion thunder rumbles? Yes, I think there is some thunder potential Saturday evening, even on the cool side of the boundary. Link to comment Share on other sites More sharing options...
high risk Posted September 2, 2017 Share Posted September 2, 2017 well, I talked up the Saturday evening potential, and I'm going to officially cancel it now. warm sector will be confined way southeast of DC Metro Link to comment Share on other sites More sharing options...
Kmlwx Posted September 4, 2017 Share Posted September 4, 2017 NAM nest looks actually okay for tomorrow PM on the sim radar. Link to comment Share on other sites More sharing options...
high risk Posted September 5, 2017 Share Posted September 5, 2017 7 hours ago, Kmlwx said: NAM nest looks actually okay for tomorrow PM on the sim radar. agreed, and the shear is decent too. The only thing lacking is more instability, as low-level moisture is only modest, so the cape is tall and skinny. if we had 70's dew points, this would be an enhanced day. Link to comment Share on other sites More sharing options...
yoda Posted September 5, 2017 Share Posted September 5, 2017 From this morning's AFD: .NEAR TERM /TODAY/... An upper level trough will descend towards the Mid-Atlantic, buckling as it collides with a building ridge over the northwestern Atlantic. This will cause a strengthening mid/upper jet through the day. At the surface, a cold front will slowly approach from the west, and increasing low-level convergence will increase by afternoon. Although mid-level lapse rates are not all that spectacular, increasing low-level moisture combined with daytime heating will result in roughly 1000-2000 J/kg of CAPE. The increasing upper jet will result in 30-40 kts of effective shear by mid-afternoon into the early evening, highest across the northern parts of the CWA. Showers and scattered thunderstorms appear likely, some of which may contain gusty winds along with a marginal flash flood risk. There will be potential for training, but storm motion will be fast. The main storm mode should be linear segments and multicell clusters, though semi-discrete/transient supercell structures cannot be ruled out given the magnitude of the shear. The best coverage of stronger storms should be mainly north of I-66 where the best convergence/shear is. Gusty winds would be the primary hazard, with hail or an isolated tornado a secondary (though non-zero) threat. Link to comment Share on other sites More sharing options...
WVclimo Posted September 5, 2017 Share Posted September 5, 2017 STW up for OKV-MRB and surrounding area through 3:30 p.m. for wind gusts to 70 mph and quarter-size hail. Link to comment Share on other sites More sharing options...
mappy Posted September 5, 2017 Author Share Posted September 5, 2017 watch possible http://www.spc.noaa.gov/products/md/md1621.html Link to comment Share on other sites More sharing options...
mappy Posted September 5, 2017 Author Share Posted September 5, 2017 Aaand, tornado warning Link to comment Share on other sites More sharing options...
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