Severe Thunderstorm Warning 164, NWS Baltimore/Washington

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
300 PM EDT MON JUL 21 2003

...SHORT TERM (TNGT AND TUE)...

UPR LVL TROF WL SWEEP ACROSS THE REGION TONIGHT...BUT MAINLY GIVING
US A GLANCING BLOW WITH BEST DYNAMICS REMAINING N OF OUR CWA. BUT
FIRST HAVE TO DEAL WITH SHORT TERM CONVECTIVE POTENTIAL. SCATTERED
THUNDERSTORMS HAVE FORM OVER PORTIONS OF THE SHENANDOAH AND POTOMAC
HIGHLAND IN GOOD INSTABILITY AXIS. MID-LVL SHEAR IS NOT IMPRESSIVE
ALTHOUGH INSTABLITY ACTUALLY QUITE GOOD. THINK THE AREA W OF THE
BLUE RIDGE COULD SEE ISOLATED SVR DUE TO DAMAGING WINDS WITH STORMS
OVER THE NEXT FEW HOURS. THEN AS THE EVENING BEGINS...LOTS OF DEBRI
CLOUDS AND LOSS OF INSOLATION WL DIMINISH THREAT OF SVR. UPR LVL
VORT AXIS COULD BE SUFF TO MAINTAIN A BROKEN LINE OF RW/TRW THROUGH
EARLY EVENING...THEN ACTIVITY SHOULD DIMINISH OVERNIGHT.

FOR TUE...SLOW MOVING FRNTL SYSTEM WL AFFECT THE REGION. 12Z ETA
SWEEPS THROUGH ONE BATCH OF MOISTURE EARLY IN THE DAY...THEN COULD
ACTUALLY SEE SOME SUNSHINE BEFORE ANOTHER BATCH OF MOISTURE AHEAD OF
A WEAK WAVE MOVES FROM SW TO NE ACROSS THE CWA BY MID AFTN. SVR
THREAT FOR TUE WL DEPEND UPON JUST HOW MUCH SUN GETS THROUGH. EVEN
IF WE GET SOME SUN...SHEAR PROFILES DO NOT LOOK ALL THAT IMPRESSIVE.
WL KEEP CHC GOING FOR TUE.

ON THE MARINE...SEEING LOTS OF GUSTS ON/NEAR THE BAY IN THE LOW 20S
SO SCA WL CONT FOR THIS PCKG.

SMZ

EXTENDED (TUE NIGHT-MONDAY)...
SHORT AND MEDIUM RANGE MODELS CONTINUE TO TREND TOWARDS COLD FRONT
SLOWING DOWN ON WEDNESDAY AND HANGING ACROSS THE EASTERN AND
SOUTHERN ZONES THROUGH THURSDAY. AIRMASS THEN DRIES OUT FOR FRIDAY
THROUGH SUNDAY. A BRIEF BREAK IN STAGNANT UPPER PATTERN FOR LATE
WEEK INTO THE WEEKEND. RIDGE REMAINS IN THE WEST WITH FLAT FLOW IN
THE EAST. EAST COAST TROUGH REDEVELOPS AS LOW PRESSURE OVER CANADA
DIGS SOUTHWARD ON MONDAY.

WILL KEEP CHANCE POPS TUESDAY NIGHT THROUGH WEDNESDAY NIGHT THEN
TAPER OFF THURSDAY. EVIDENT FROM AREA CROSS SECTIONS...BEST LIFT AND
DEEPER MOISTURE COME INTO PHASE DURING THE DAY WEDNESDAY...ENHANCED
UPPER JET. PWATS WILL AVERAGE 1.5 IN WEST AND GREATER THAN 2 IN EAST
DURING THE PERIOD.  LIKELY POPS IN ORDER...BUT WILL LEAVE AT HIGH
END CHANCE (50%) FOR NOW.  WITH THE TIGHTER GRADIENT AND THE TRACK
OF THE SURFACE LOW...WINDS EXPECTED TO REACH SCA CRITERIA TUESDAY
AND WEDNESDAY.

HIGH PRESSURE DEVELOPS OVER THE AREA FRIDAY AND SLIDES SOUTHEAST
SATURDAY. RETURN FLOW BECOMES ESTABLISHED BY SUNDAY IN ADVANCE
OF APPROACHING SHORTWAVE FOR MONDAY. WILL CARRY A SLIGHT CHANCE POP.
/CPW

.LWX...
DC...NONE.
MD...NONE.
VA...NONE.
WV...NONE.
MARINE...NONE.

DCZ001-MDZ002>007-009>011-013-014-016>018-VAZ021-025>031-036>042-
050>057-WVZ048>055-220930-

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
1115 AM EDT MON JUL 21 2003

THIS HAZARDOUS WEATHER OUTLOOK IS FOR MARYLAND WEST OF THE CHESAPEAKE
BAY AND EAST OF GARRETT COUNTY...THE DISTRICT OF COLUMBIA...NORTHERN
VIRGINIA...THE NORTHERN AND CENTRAL SHENANDOAH VALLEY...AND THE
EASTERN PANHANDLE OF WEST VIRGINIA.

.DAY ONE...TODAY
THERE IS A SLIGHT RISK FOR SEVERE THUNDERSTORMS THIS AFTERNOON
ACROSS THE VIRGINIA SHENANDOAH VALLEY...POTOMAC HIGHLANDS INCLUDING
THE EASTERN WEST VIRGINIA PANHANDLE AND WESTERN MARYLAND. PRIMARY
THREAT TIME WILL BE FROM ABOUT 3 PM THROUGH 7 PM. THE MAIN THREAT
WILL BE FROM DAMAGING THUNDERSTORM WINDS. SOME AREAS COULD SEE A
QUICK INCH OF RAIN IN LESS THAN AN HOUR.

.DAYS TWO THROUGH SEVEN...

THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER THE ENTIRE
REGION ON TUESDAY.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION MAY BE REQUIRED BY MID AFTERNOON.

SMZ