Severe Thunderstorm Warning 189, NWS Baltimore/Washington

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BALTIMORE/WASHINGTON
1020 AM EDT MON AUG 5 2002

SHRA/TSRA OVR SE PA WEAKENING AS IT CLIPS EXTREME NE ZNS. THIS
CONVECTION IN ASSOCN WITH WEAK SHORTWAVE AND SFC BOUNDARY MOVING
THRU PA. WILL HANDLE ANY ACTIVITY OVR HARFORD CO NEXT HOUR WITH
NOWCASTS.

TEMPS YDA REACHED THE UPR 90S MANY LOCATIONS WITH A COUPLE OF SPOTS
AT 100F. 850MB TEMPS JUST AS WARM TDA WITH PLENTY OF SUNSHINE. IN
ADDTN...SFC FLOW FCST BY THE MODELS TO BECOME MORE SW AND PSBLY W
THIS AFTRN WHICH WOULD RESULT IN SOME DOWNSLOPING AND WARMING. WOULD
NOT BE SURPRISED TO SEE MANY SITES NEAR 100F THIS AFTRN. WILL RAISE
MAX TEMPS TO 96 TO 101 ACROSS MUCH OF THE AREA EXCEPT THE HIER
ELEVS. WILL GO NEAR 100 IN THE CITIES. DWPTS MAY FALL OFF A BIT THIS
AFTRN IF WINDS TURN MORE WESTERLY... BUT HIER TEMPS WILL COMPENSATE
AND WE SHOULD HAVE NO PROBLEM REACHING HEAT ADVISORY CRITERIA. WILL
EXTEND ADVISORY UNTIL 8 PM.

NOW FOR THE CONVECTIVE POTENTIAL. 12Z MODIFIED IAD SOUNDING YIELDED
A CAPE OF 3000 J/KG AND LI OF -7C THIS AFTRN SO AIR MASS WILL BE
UNSTABLE. COULD SEE SOME SCT CONVECTION FIRE DURING THE AFTRN OVR
THE MTNS DUE TOI OROGRAPHIC LIFT AND ALG THE LEE SIDE TROF THAT IS
FCST TO SET UP. WIND FIELDS ARE NOT THAT IMPRESSIVE THIS AFTRN BUT
CANT RULE OUT ISOLD SVR.

THE BETTER CHC OF SVR WILL COME BETWEEN 6 PM AND MIDNIGHT AS
PREFRONTAL TROUGH MOVES THRU THE AREA. IN ADDTN...WIND FIELDS ARE
SLIGHTLY STRONGER AND LAPSE RATES STEEPEN JUST A BIT. THINK CHC IS
GOOD FOR SVR DURING THE FIRST PART OF THE NIGHT. ACTUAL FRONT COMES
THROUGH AFTER MIDNIGHT...USHERING IN A MUCH COOLER AIR MASS FOR TUE.

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

WALSTON

DCZ001-MDZ002>007-009>011-013-014-016>018-VAZ021-025>031-036>042-050>
057-WVZ048>055-060000-

SEVERE WEATHER OUTLOOK
NATIONAL WEATHER SERVICE BALTIMORE/WASHINGTON
1100 AM EDT MON AUG 5 2002

THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS LATE THIS AFTERNOON
INTO TONIGHT ACROSS ALL OF NORTHERN AND WEST CENTRAL VIRGINIA...MUCH
OF MARYLAND...EASTERN WEST VIRGINIA AND THE DISTRICT OF COLUMBIA.

A COLD FRONT WILL BE APPROACHING THE AREA THIS EVENING.
THUNDERSTORMS ARE EXPECTED TO DEVELOP AHEAD OF THE FRONT IN THE HOT
UNSTABLE AIR MASS OVER THE AREA LATE THIS AFTERNOON AND THIS EVENING.
THE BIGGEST THREAT FROM SEVERE THUNDERSTORMS WILL BE DAMAGING WINDS
AND INTENSE LIGHTNING. IN ADDITION...HAIL IS POSSIBLE. THE STORMS
ARE EXPECTED TO BE MOVING SLOWLY...SO HEAVY RAINFALL MAY RESULT IN
FLOODING OF LOW LYING AND POOR DRAINAGE AREAS THIS EVENING.

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

WALSTON