yoda Posted September 8, 2012 Share Posted September 8, 2012 MESOSCALE DISCUSSION 1933 NWS STORM PREDICTION CENTER NORMAN OK 0112 PM CDT SAT SEP 08 2012 AREAS AFFECTED...ERN PA...NJ...MD...NRN VA/DE...DC CONCERNING...SEVERE THUNDERSTORM WATCH 636... VALID 081812Z - 081945Z THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 636 CONTINUES. SUMMARY...DAMAGING WIND THREAT INCREASING AS COLD FRONT MERGES WITH PRE-FRONTAL CONVECTIVE BAND. EMBEDDED LEWPS/BOWING STRUCTURES WILL BE CAPABLE OF ENHANCED/SIGNIFICANT WIND DAMAGE WITH COVERAGE LIKELY INCREASING SUBSTANTIALLY. DISCUSSION...COLD FRONT FROM BRADFORD COUNTY PA TO HIGHLAND COUNTY VA AS OF 18Z. THIS FRONT IS ABOUT TO MERGE WITH PRE-FRONTAL CONVECTION THAT HAS DEVELOPED ALONG A DIFFERENTIAL HEATING ZONE. AS THIS PROCESS OCCURS AMIDST A DOWNSTREAM AIR MASS CHARACTERIZED BY SURFACE TEMPERATURES IN THE 80S TO LOWER 90S...THIS QLCS SHOULD INTENSIFY. DEEP-LAYER SHEAR WILL BE FAVORABLE FOR BOWING/LEWP STRUCTURES CAPABLE OF POTENTIALLY SIGNIFICANT/NUMEROUS REPORTS OF WIND DAMAGE. A BRIEF TORNADO OR TWO IS ALSO POSSIBLE PARTICULARLY ACROSS THE NRN PORTION OF WW 636 ON THE FRINGE OF STRONGER LOW-LEVEL SWLYS. Link to comment Share on other sites More sharing options...
Ian Posted September 8, 2012 Share Posted September 8, 2012 We gonna get rocked. Link to comment Share on other sites More sharing options...
Mrs.J Posted September 8, 2012 Share Posted September 8, 2012 This shot was taken from the 4th level of a parking garage in Downtown Frederick around 1:30. It is looking off to the NW. This is the storm that was warned for a time down here. It did not do anything, but as we drove home we got a very large rush of cold air. It has now been pouring for close to 10 min. Here is an image prior to the one shot above as we headed back to the car. Link to comment Share on other sites More sharing options...
yoda Posted September 8, 2012 Share Posted September 8, 2012 1800z SPC Meso FWIW: 1000 MLCAPE, 2000 SBCAPE, LI -4, 40-50 kts effective bulk shear, 40kts 0-6km shear Link to comment Share on other sites More sharing options...
Kmlwx Posted September 8, 2012 Author Share Posted September 8, 2012 We gonna get rocked. HINTS OF A DERECHO Link to comment Share on other sites More sharing options...
yoda Posted September 8, 2012 Share Posted September 8, 2012 BULLETIN - EAS ACTIVATION REQUESTED TORNADO WARNING NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC 228 PM EDT SAT SEP 8 2012 THE NATIONAL WEATHER SERVICE IN STERLING VIRGINIA HAS ISSUED A * TORNADO WARNING FOR... NORTHEASTERN SHENANDOAH COUNTY IN NORTHWEST VIRGINIA... NORTHWESTERN WARREN COUNTY IN NORTHWEST VIRGINIA... SOUTHERN FREDERICK COUNTY IN NORTHWEST VIRGINIA... * UNTIL 300 PM EDT * AT 225 PM EDT...A SEVERE THUNDERSTORM CAPABLE OF PRODUCING A TORNADO WAS NEAR STRASBURG...AND WAS MOVING NORTHEAST AT 25 MPH. * LOCATIONS IMPACTED INCLUDE... STEPHENS CITY... FISHERS HILL... STRASBURG... MIDDLETOWN... Link to comment Share on other sites More sharing options...
Kmlwx Posted September 8, 2012 Author Share Posted September 8, 2012 Hopefully the outflow racing out ahead won't kill off the main show. Looking realllllly nice as of now. Hopefully Ian doesn't get blown away on the mall. Link to comment Share on other sites More sharing options...
TalcottWx Posted September 8, 2012 Share Posted September 8, 2012 Very curious to see how this develops as it near us. Exciting! Link to comment Share on other sites More sharing options...
H2O Posted September 8, 2012 Share Posted September 8, 2012 Hopefully the outflow racing out ahead won't kill off the main show. Looking realllllly nice as of now. Hopefully Ian doesn't get blown away on the mall. DC south will have to watch and see how much further S that line builds Link to comment Share on other sites More sharing options...
yoda Posted September 8, 2012 Share Posted September 8, 2012 Hopefully there was a 18z SPEC sounding, should be interesting to see Link to comment Share on other sites More sharing options...
Kmlwx Posted September 8, 2012 Author Share Posted September 8, 2012 Radar has the general "look" that a few of our good wind damage events have had. Big line racing out of the Shenandoah area. Link to comment Share on other sites More sharing options...
yoda Posted September 8, 2012 Share Posted September 8, 2012 Right turner in Shenendoah/Frederick/Warren area? Link to comment Share on other sites More sharing options...
eurojosh Posted September 8, 2012 Share Posted September 8, 2012 DC south will have to watch and see how much further S that line builds Yeah - if it's a race between those outflow pop-ups approaching warrenton, versus the main line which is still in Shenandoah, DC may get zapped by the small deal... Any hopes they can re-unite before approaching? Link to comment Share on other sites More sharing options...
TalcottWx Posted September 8, 2012 Share Posted September 8, 2012 Going to get crushed here maybe. Going to have to head out in the car. Link to comment Share on other sites More sharing options...
Disc Posted September 8, 2012 Share Posted September 8, 2012 Meh. You guys have fun with those storms. I'm getting my gusty rain showers it looks! Link to comment Share on other sites More sharing options...
yoda Posted September 8, 2012 Share Posted September 8, 2012 Link to comment Share on other sites More sharing options...
Fozz Posted September 8, 2012 Share Posted September 8, 2012 Still partly sunny, but with very dark clouds to my north. Link to comment Share on other sites More sharing options...
yoda Posted September 8, 2012 Share Posted September 8, 2012 BULLETIN - EAS ACTIVATION REQUESTED SEVERE THUNDERSTORM WARNING NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC 247 PM EDT SAT SEP 8 2012 THE NATIONAL WEATHER SERVICE IN STERLING VIRGINIA HAS ISSUED A * SEVERE THUNDERSTORM WARNING FOR... WESTERN MONTGOMERY COUNTY IN CENTRAL MARYLAND... RAPPAHANNOCK COUNTY IN NORTHWEST VIRGINIA... WARREN COUNTY IN NORTHWEST VIRGINIA... NORTHWESTERN CULPEPER COUNTY IN NORTHERN VIRGINIA... CLARKE COUNTY IN NORTHWEST VIRGINIA... NORTHWESTERN MADISON COUNTY IN NORTHWEST VIRGINIA... PAGE COUNTY IN NORTHWEST VIRGINIA... SOUTHERN JEFFERSON COUNTY IN THE PANHANDLE OF WEST VIRGINIA... NORTHWESTERN PRINCE WILLIAM COUNTY IN NORTHERN VIRGINIA... LOUDOUN COUNTY IN NORTHERN VIRGINIA... FAUQUIER COUNTY IN NORTHERN VIRGINIA... * UNTIL 400 PM EDT * AT 242 PM EDT...SEVERE THUNDERSTORMS WERE DETECTED ALONG A LINE EXTENDING FROM BERRYVILLE TO STANLEY...AND WERE MOVING EAST AT 35 MPH. THIS LINE OF STORMS IS CAPABLE OF PRODUCING DESTRUCTIVE WINDS IN EXCESS OF 70 MPH. Link to comment Share on other sites More sharing options...
Kmlwx Posted September 8, 2012 Author Share Posted September 8, 2012 Cool radar loop. Notice how the main line goes from moving NEish to surging east. Link to comment Share on other sites More sharing options...
Fozz Posted September 8, 2012 Share Posted September 8, 2012 Winds picking up Link to comment Share on other sites More sharing options...
EastCoast NPZ Posted September 8, 2012 Share Posted September 8, 2012 Can confirm no tornado in Stephens City. Did have a nice gusty shower. Winds changed direction in the middle of the storm so seems like there was rotation. Odd though that there was not one clap of thunder during the storm. Radar showed lots of orange and red. Don't know if I've ever seen that and not had a t-storm. Would estimate some 40 mph gusts during the storm. Rain drops were very small also. Don't know what that means, but don't normally see that with such radar echos. Haven't checked the rain gage yet; trying to get my daughter down for a nap. Best part is that the temp fell from a high of 83 or 85 (depending on which station you believe) to 59F. Nice. Link to comment Share on other sites More sharing options...
AmericanWxFreak Posted September 8, 2012 Share Posted September 8, 2012 Better not get split here in Columbia Link to comment Share on other sites More sharing options...
Fozz Posted September 8, 2012 Share Posted September 8, 2012 Rain Link to comment Share on other sites More sharing options...
D-Train Posted September 8, 2012 Share Posted September 8, 2012 Who wants to come be an anchor for my trampoline.... (fearing these winds) Link to comment Share on other sites More sharing options...
TalcottWx Posted September 8, 2012 Share Posted September 8, 2012 Looks like the end of the world to my northwest Link to comment Share on other sites More sharing options...
Fozz Posted September 8, 2012 Share Posted September 8, 2012 Looks like the end of the world to my northwest lol. I'm NW of you and it's just a typical downpour. Link to comment Share on other sites More sharing options...
PhineasC Posted September 8, 2012 Share Posted September 8, 2012 I'm going to get the split. Link to comment Share on other sites More sharing options...
yoda Posted September 8, 2012 Share Posted September 8, 2012 ...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 400 PM EDT FOR FAUQUIER...LOUDOUN...PRINCE WILLIAM...MADISON...CULPEPER... RAPPAHANNOCK AND MONTGOMERY COUNTIES... AT 305 PM EDT...SEVERE THUNDERSTORMS WERE DETECTED ALONG A LINE EXTENDING FROM 5 MILES SOUTH OF PURCELLVILLE TO 5 MILES SOUTHWEST OF SPERRYVILLE...AND WERE MOVING EAST AT 35 MPH. THESE STORMS ARE CAPABLE OF PRODUCING HAIL UP TO THE SIZE OF HALF DOLLARS AND DESTRUCTIVE WINDS IN EXCESS OF 70 MPH. LOCATIONS IMPACTED INCLUDE... OATLANDS... MIDDLEBURG... LEESBURG... BOSTON... THE PLAINS... LANSDOWNE... BROADLANDS... ASHBURN... COUNTRYSIDE... STERLING... SOUTH RIDING... THIS LINE OF STORMS HAS A HISTORY OF PRODUCING DAMAGING WIND GUSTS AND LARGE HAIL. SEEK SHELTER INSIDE A STURDY STRUCTURE AND STAY AWAY FROM WINDOWS. Link to comment Share on other sites More sharing options...
AmericanWxFreak Posted September 8, 2012 Share Posted September 8, 2012 I'm going to get the split. Me too Link to comment Share on other sites More sharing options...
snowfan Posted September 8, 2012 Share Posted September 8, 2012 Meh....looks sloppy. Link to comment Share on other sites More sharing options...
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