Flash Flood Warning 77, NWS Baltimore/Washington

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
953 AM EDT SAT AUG 10 2013

.SYNOPSIS...
A COLD FRONT WILL STALL OVER THE REGION TODAY...AND REMAIN IN THE
AREA THROUGH EARLY NEXT WEEK. A STRONGER COLD FRONT WILL SWEEP
THROUGH THE MID-ATLANTIC ON TUESDAY. HIGH PRESSURE WILL BUILD IN
FOR THE END OF THE WEEK.

&&

.NEAR TERM /THROUGH TONIGHT/...
COLD FRONT HAS JUST ABOUT STALLED IN THE VICINITY OF LOWER
SOUTHERN MD WEST ACROSS CENTRAL VA. NORTH OF THIS BOUNDARY A MORE
STABLE ENVIRONMENT WITH OVERCAST CONDITIONS REMAINS IN PLACE WITH
DRIER AIR NOTED UPSTREAM INTO PA. SOUTH OF THE BOUNDARY...LOWER
ATMOSPHERE IS MORE UNSTABLE. THINK FOCUS FOR CONVECTIVE ACTIVITY
WILL BE SOUTH THIS AFTERNOON WITH MORE LIGHT RAIN EXPECTED NORTH.
HAVE REMOVED THUNDER MENTION THROUGH EARLY AFTERNOON BUT
REINTRODUCED THREAT FOR THUNDER IN THE 18-00Z TIMEFRAME GIVEN
POTENTIAL FOR BREAKS IN THE OVERCAST. TEMPS A BIT TRICKY TODAY
GIVEN OVERCAST NORTH AND BREAKS SOUTH. KEPT THINGS FAIRLY COOL
UPPER 70S TO LOW 80S NORTH MID-UPPER 80S SOUTH.

FOG WILL BE POSSIBLE OVERNIGHT WITH BREAKS IN THE CLOUD COVER
EXPECTED. WILL CONTINUE PATCHY WORDING AND EVALUATE FURTHER FOR
THE AFTERNOON PACKAGE.

&&

.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
THE STALLED FRONTAL BOUNDARY OVER CENTRAL VA WILL BE MOVING
NORTHWARD SUNDAY AFTERNOON AND EVENING AS A WARM FRONT.  A PLUME
OF MOISTURE WILL ENTER THE MID ATLANTIC WITH PWATS CLOSE TO 2
INCHES AND DEWPTS IN THE LOW 70S BY SUN AFTERNOON. SHOWERS AND
SCATTERED THUNDERSTORMS WILL BE POSSIBLE THROUGHOUT THE DAY
ESPECIALLY ALONG THE FROPA. LACK OF INSTABILITY AND SHEAR WILL
LEAD TO WEAK THUNDERSTORMS BUT THEY WILL BE CAPABLE OF HEAVY RAIN.
THIS ACTIVITY WILL MOVE EASTWARD INTO SUNDAY NIGHT. MID LEVEL DRY
AIR WILL ENTER THE MID ATLANTIC BEHIND FROPA AS IT MOVES OFF THE
ATLANTIC COAST. RADIATION FOG WILL BE POSSIBLE INTO MONDAY MORNING
ESPECIALLY IF CLEARING OCCURS OVER AREAS THAT HAVE SEEN RAINFALL.

ZONAL FLOW WILL PERSIST OVER THE MID ATLANTIC ON MONDAY.  THE FROPA
SHOULD BE OFF THE COAST LEADING TO A LESS HUMID DAY WITH PWAT VALUES
NEAR 1.35IN AND LIGHT NW FLOW AT THE SFC.  FLOW WILL QUICKLY TURN TO
THE SOUTH TOWARDS MONDAY EVENING AND MOISTURE WILL START TO INCREASE
ACROSS THE REGION.  SHOWERS WILL BE POSSIBLE MAINLY ACROSS THE
PIEDMONT AND MARINE ZONES AS OVERRUNNING TAKES PLACE AHEAD OF
ANOTHER COLD FRONT THAT WILL APPROACH FROM THE GREAT LAKES
REGION.

&&

.LONG TERM /TUESDAY THROUGH FRIDAY/...
A UPPER LEVEL TROUGH WILL APPROACH FROM THE NORTHWEST ON TUESDAY.  A
COLD FRONT WILL MOVE ACROSS THE OHIO VALLEY MONDAY NIGHT AND ENTER
THE MTNS BY TUESDAY MORNING.  THE MID ATLANTIC WILL BE IN THE WARM
SECTOR AHEAD OF THE FRONT TUESDAY AND PWATS WILL INCREASE TO AROUND
2 INCHES...2+ INCHES NEAR THE PIEDMONT AND SOUTHERN MD.  MULTIPLE
SHORTWAVE TROUGHS WILL CROSS THE REGION AHEAD AND WITH THE FROPA.
MARGINAL INSTABILITY AND SHEAR IS EXPECTED BUT ABUNDANT MOISTURE AND
ADDED LIFT FROM FROPA AND UPPER LEVEL DYNAMICS WILL AID IN ISO-SCT
THUNDERSTORM DEVELOPMENT.

COLD FRONT CROSSES SOUTHERN MD BY WEDNESDAY MORNING AND NORTHWEST
FLOW WILL TRANSPORT UPPER 50 DEWPTS TO THE MID ATLANTIC WEDNESDAY.
HIGH PRESSURE WILL BUILD INTO THE MID ATLANTIC FOR THE END OF THE
WORK WEEK.  TEMPERATURES WILL BE NEAR OR SLIGHTLY BELOW NORMAL FOR
THE LONG TERM.

&&

.AVIATION /14Z SATURDAY THROUGH WEDNESDAY/...
AREAS OF LIGHT RAIN AND OVERCAST CONDITIONS EXPECTED TODAY WITH
THUNDER POTENTIAL POSSIBLE AT CHO. FOG POSSIBLE OVERNIGHT IF
CLEARING COMMENCES.

A WARM FRONT WILL MOVE NORTHWARD SUNDAY AND SHOWERS AND ISO-SCT
THUNDERSTORMS ARE POSSIBLE.  MVFR/IFR CONDITIONS ARE POSSIBLE WITHIN
ACTIVITY.  FOG WILL BE POSSIBLE SUNDAY NIGHT INTO MONDAY.  ANOTHER
COLD FRONT CROSSES THE REGION TUESDAY AND SHOWERS AND SCT
THUNDERSTORMS ARE EXPECTED.

&&

.MARINE...
WITH A FRONT...ALBEIT A WEAK ONE...IN THE VICINITY...WINDS SHOULD BE
LIGHT THROUGH TONIGHT.

A WARM FRONT WILL MOVE NORTHWARD ACROSS THE WATERS SUNDAY.  SHOWERS
AND ISO THUNDERSTORMS ARE POSSIBLE.  ANOTHER COLD FRONT WILL CROSS
THE REGION TUESDAY.

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...NONE.
VA...NONE.
WV...NONE.
MARINE...NONE.

&&

SYNOPSIS...KRW
NEAR TERM...KRW
SHORT TERM...HAS
LONG TERM...HAS
AVIATION...HAS/KRW
MARINE...HAS/KRW

HAZARDOUS WEATHER OUTLOOK...UPDATED
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
958 AM EDT SAT AUG 10 2013

ANZ530>543-DCZ001-MDZ006-007-011-013-014-016>018-VAZ052>057-
111200-
CHESAPEAKE BAY NORTH OF POOLES ISLAND MD-
CHESAPEAKE BAY FROM POOLES ISLAND TO SANDY POINT MD-
CHESAPEAKE BAY FROM SANDY POINT TO NORTH BEACH MD-
CHESAPEAKE BAY FROM NORTH BEACH TO DRUM POINT MD-
CHESAPEAKE BAY FROM DRUM POINT MD TO SMITH POINT VA-
TIDAL POTOMAC FROM KEY BRIDGE TO INDIAN HEAD MD-
TIDAL POTOMAC FROM INDIAN HEAD TO COBB ISLAND MD-
TIDAL POTOMAC FROM COBB ISLAND MD TO SMITH POINT VA-
PATAPSCO RIVER INCLUDING BALTIMORE HARBOR-
CHESTER RIVER TO QUEENSTOWN MD-EASTERN BAY-
CHOPTANK RIVER TO CAMBRIDGE MD AND THE LITTLE CHOPTANK RIVER-
PATUXENT RIVER TO BROOMES ISLAND MD-
TANGIER SOUND AND THE INLAND WATERS SURROUNDING BLOODSWORTH
ISLAND-DISTRICT OF COLUMBIA-NORTHERN BALTIMORE-HARFORD-
SOUTHERN BALTIMORE-PRINCE GEORGES-ANNE ARUNDEL-CHARLES-ST. MARYS-
CALVERT-PRINCE WILLIAM/MANASSAS/MANASSAS PARK-FAIRFAX-
ARLINGTON/FALLS CHURCH/ALEXANDRIA-STAFFORD-SPOTSYLVANIA-
KING GEORGE-
958 AM EDT SAT AUG 10 2013

THIS HAZARDOUS WEATHER OUTLOOK IS FOR THE MARYLAND PORTION OF THE
CHESAPEAKE BAY...TIDAL POTOMAC RIVER...AND ADJACENT COUNTIES IN
CENTRAL MARYLAND AND NORTHERN VIRGINIA AS WELL AS THE DISTRICT OF
COLUMBIA.

.DAY ONE...TODAY AND TONIGHT

SHOWERS AND ISOLATED THUNDERSTORMS WILL BE POSSIBLE INTO TONIGHT.
SOME OF THE STORMS COULD PRODUCE HEAVY DOWNPOURS AND LOCALIZED
FLOODING.

.DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY

NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION IS NOT EXPECTED AT THIS TIME.

MDZ003>005-009-010-501-502-VAZ025>031-036>040-042-050-051-501>504-
WVZ050>053-055-501>506-111200-
WASHINGTON-FREDERICK MD-CARROLL-MONTGOMERY-HOWARD-
EXTREME WESTERN ALLEGANY-CENTRAL AND EASTERN ALLEGANY-AUGUSTA-
ROCKINGHAM-SHENANDOAH-FREDERICK VA-PAGE-WARREN-CLARKE-NELSON-
ALBEMARLE-GREENE-MADISON-RAPPAHANNOCK-LOUDOUN-ORANGE-CULPEPER-
NORTHERN FAUQUIER-SOUTHERN FAUQUIER-WESTERN HIGHLAND-
EASTERN HIGHLAND-HAMPSHIRE-MORGAN-BERKELEY-JEFFERSON-HARDY-
WESTERN GRANT-EASTERN GRANT-WESTERN MINERAL-EASTERN MINERAL-
WESTERN PENDLETON-EASTERN PENDLETON-
958 AM EDT SAT AUG 10 2013

THIS HAZARDOUS WEATHER OUTLOOK IS FOR EASTERN WEST VIRGINIA...
NORTHERN AND CENTRAL VIRGINIA...AND CENTRAL AND WESTERN MARYLAND
WITH THE EXCEPTION OF GARRETT COUNTY.

.DAY ONE...TODAY AND TONIGHT

SHOWERS AND ISOLATED THUNDERSTORMS TODAY WILL BE CAPABLE OF
PRODUCING HEAVY RAINFALL...WHICH COULD RESULT IN LOCALIZED FLASH
FLOODING...MAINLY IN THE SOUTHERN SHENANDOAH VALLEY AND CENTRAL
VIRGINIA FOOTHILLS. GUSTY WINDS ARE ALSO POSSIBLE IN THUNDERSTORMS
IN THE SAME AREAS.

.DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY

NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION IS NOT EXPECTED AT THIS TIME.