MESOSCALE DISCUSSION 2287
NWS STORM PREDICTION CENTER NORMAN OK
0124 PM CDT WED AUG 27 2003
AREAS AFFECTED...ERN WV PNHDL...NRN VA...WRN/CNTRL MD AND DISTRICT
OF COLUMBIA
CONCERNING...SEVERE THUNDERSTORM WATCH 900...
VALID 271824Z - 271915Z
AMENDED FOR WW REASONING
AMENDED PORTION:
AFTER COLLABORATION WITH WFO STERLING...WILL LEAVE WS 900 INTACT
WITH ANTICIPATION THAT STRONG-SEVERE CONVECTION TO THE WEST WILL
MOVE INTO THE REGION LATER THIS AFTERNOON. WS 900 MAY BE EXTENDED
INTO THE EVENING IF THE UPSTREAM CONVECTION CAN BE MAINTAINED.
REST OF DISCUSSION UNCHANGED...
EARLIER TSTMS THAT MOVED INTO WRN/CNTRL MD DIMINISHED RAPIDLY OVER
THE PAST FEW HOURS. WW HAS BEEN MAINTAINED GIVEN UNCERTAINTY IF
TSTMS WOULD INITIATE ALONG OUTFLOW BOUNDARIES IN NRN VA/CNTRL MD.
THUSFAR...THEY HAVE NOT FORMED DESPITE AN AIR MASS THAT IS MOISTURE
RICH AND VERY UNSTABLE. IT APPEARS THAT LACK OF SUBSTANTIAL LARGE
SCALE ASCENT AND GENERAL DOWNSLOPING LOW LEVEL FLOW HAS BEEN
DETRIMENTAL IN GETTING ENOUGH CONVERGENCE TO SUSTAIN DEEP MOIST
CONVECTION.
HOWEVER...ANOTHER IMPULSE EMBEDDED ALONG SRN PERIPHERY OF THE WLYS
IS MOVING INTO THE OH VLY AND IS SUPPORTING A VIGOROUS CLUSTER OF
TSTMS WITH THE HISTORY OF WIND DAMAGE ACROSS SRN OH. EXTRAPOLATION
HAS THIS CLUSTER CROSSING THE APPALACHIAN MTNS AND INTO THE ERN WV
PNHDL AND WRN MD BETWEEN 21-22 UTC. IF THIS CLUSTER CAN BE
MAINTAINED...THE SEVERE THREAT WILL INCREASE WITH THE MAIN THREAT
BEING DAMAGING WINDS.
..RACY.. 08/27/2003
ATTN...WFO...PHI...AKQ...LWX...PBZ...
38257928 39707926 39597628 38187633
|