Severe Thunderstorm Warning 167, NWS Baltimore/Washington

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BALTIMORE/WASHINGTON
1100 AM EDT SAT AUG 3 2002

WEAK DIFFUSE CDFNT HARD TO FIND THIS MORNING BUT MSAS ANALYSIS SEEMS
TO INDICATE WHATEVER THATS LEFT OF THE FRONT IS LOCATED OVR SRN PA.
12Z MODIFIED IAD SOUNDING YIELDS LIS OF -8C TO -10C THIS AFTERNOON
WITH CAPES EXCEEDING 4000 J/KG SO AIR MASS WILL BE UNSTABLE.
QUITE A FEW WAYS TO GET CONVECTION GOING THIS AFTRN. WEAKENING FRONT
TO THE N OF THE AREA MAY ACT AS A FOCUS FOR SCT CONVECTION THIS
AFTERNOON. ALSO....MODELS HINT AT VERY WEAK VORT MAX DRIFTING SW
ACRS THE AREA. THIS MAY ALSO HELP TO INITIATE CONVECTION. IN
ADDITION...THERE MAY BE MESOSCALE BOUNDARIES LAID OUT OVR THE AREA
DUE TO LAST NIGHTS CONVECTION. THESE BOUNDARIES COULD INITIATE
CONVECTION. AND FINALLY...IF SFC WINDS TURN MORE SE...UPSLOPE
AGAINST THE MTNS COULD ENHANCE OROGRAPHIC LIFT POTENTIAL. WILL LEAVE
30 POPS IN PLACE FOR THE AFTRN HOURS.  AS FAR AS POTENTIAL FOR SVR...
DYNAMICS ARE LACKING AND WIND FIELDS ARE WEAK BUT CANT RULE OUT
ISOLD SVR. BIGGEST THREAT MAY BE HEAVY RAIN AS HIGH PWATS AND WEAK
STEERING FLOW COULD RESULT IN VERY SLOW MOVING HEAVY RAINERS.

NEXT PROBLEM IS THE HEAT. TEMPS MAY BE A DEG OR TWO LOWER THAN YDA
IF WINDS TURN MORE SE AND 850MB TEMPS COOL A DEG OR TWO AS FCSTD BY
THE ETA. EVEN IF THEY WERE A LTL COOLER THAN YDA...THAT STILL PLACES
THEM IN THE UPR 90S MANY AREAS. IN ADDTN...12Z SOUNDING FULL SUN MAX
FCST IS 99 FOR IAD. WILL BUMP TEMPS UP JUST A BIT MOST AREAS.

HEAT INDEX DID NOT FALL BELOW 80F LAST NIGHT AT DCA. IN
ADDTN...DEWPOINT REMAINS HIGH AT DCA. HIGH DWPTS COMBINED WITH TEMPS
IN THE UPR 90S WILL RESULT IN HEAT INDICES OF 100 TO 110 TODAY. WITH
THE 80F CRITERIA MET LAST NIGHT AND 100 TO 110 HI THIS
AFTRN...ADVISORY WILL BE UPGRADED TO A WARNING FOR DC AND THE URBAN
AREAS AROUND DC. WILL NOT BE UPGRADING TO A WARNING FOR BALTIMORE
BECAUSE DMH (DOWNTOWN BALTIMORE) HEAT INDEX FELL BELOW 80F LAST
NIGHT. HEAT ADVISORY REMAINS UP REMAINDER OF AREA EXCEPT HIGHLAND
AND PENDLETON COUNTIES.

.LWX...
DC...EXCESSIVE HEAT WARNING UNTIL 800 PM EDT SATURDAY FOR ZONE
     DCZ001.
MD...HEAT ADVISORY UNTIL 800 PM EDT SATURDAY FOR ZONES
     MDZ002>007...MDZ009>011...MDZ013>014...MDZ016>018.
VA...EXCESSIVE HEAT WARNING UNTIL 800 PM EDT SATURDAY FOR ZONE
     VAZ054.
     HEAT ADVISORY UNTIL 800 PM EDT SATURDAY FOR ZONES
     VAZ025>031...VAZ036>042...VAZ050>053...VAZ055>057.
WV...HEAT ADVISORY UNTIL 800 PM EDT SATURDAY FOR ZONES
     WVZ048>053...WVZ055.

WALSTON

DCZ001-MDZ002>007-009>011-013-014-016>018-VAZ021-025>031-036>042-
050>053-055>057-WVZ048>055-040000-

SEVERE WEATHER OUTLOOK
NATIONAL WEATHER SERVICE BALTIMORE/WASHINGTON
1152 AM EDT SAT AUG 3 2002

THERE IS A SLIGHT RISK OF ISOLATED SEVERE THUNDERSTORMS THIS
AFTERNOON OVER NORTHERN AND WEST CENTRAL VIRGINIA...MUCH OF
MARYLAND...EASTERN WEST VIRGINIA AND THE DISTRICT OF COLUMBIA.

SCATTERED THUNDERSTORMS ARE EXPECTED OVER THE REGION THIS AFTERNOON
INTO EARLY EVENING. ANY THUNDERSTORM THAT FORMS WILL HAVE THE
POTENTIAL TO BE SEVERE WITH DAMAGING WINDS AND FREQUENT LIGHTNING.
IN ADDITION...ANY STORMS THAT FORM WILL BE SLOW MOVING WHICH COULD
RESULT IN MINOR FLOODING OF LOW LYING AND POOR DRAINAGE AREAS.

IF THREATENING WEATHER APPROACHES YOUR AREA...SEEK SHELTER. STAY
TUNED TO NOAA WEATHER RADIO AND OTHER LOCAL MEDIA FOR FURTHER
DETAILS OR UPDATES.

WALSTON