Flash Flood Warning 46, NWS Baltimore/Washington

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
324 PM EDT TUE AUG 12 2014

.SYNOPSIS...
LOW PRESSURE IS CENTERED OVER THE EASTERN GREAT LAKES WITH A WARM
FRONT EXTENDING INTO SOUTHERN VRIGINIA AND EASTERN NORTH CAROLINA. A
COLD FRONT EXTENDS TO EASTERN TENNESSEE. THE COLD FRONT WILL CROSS THE
AREA EARLY WEDNESDAY MORNING. HIGH PRESSURE WILL RETURN FOR THE
SECOND HALF OF THE WEEK AND INTO THE WEEKEND.

&&

.NEAR TERM /UNTIL 3 AM WEDNESDAY MORNING/...

A PLUME OF TROPICAL MOISTURE CONTS ACROSS THE MD PORTION OF THE
BALT/WASH METRO AREA. RAFL RATES WITHIN THIS AREA HAVE BEEN
PROLIFIC...AND HV BEEN UNDERESTIMATED BY RADAR ESTIMATES. A FLASH
FLOOD WATCH IN EFFECT...AS ARE NMRS FLOOD WARNINGS. THE WATCH
CONTS THRU 2AM. BASED ON LTST TRENDS...AM THINKING THAT THIS SHUD
BE ABLE TO BE CLEARED ERLR THAN THAT. WL ALLOW REAL TIME OBS TO
DETERMINE WHEN.

ALTHO SFC-BASED INSTBY HAS BEEN INHIBITED BY SATURATED AMS...
DAYTIME HTG FM ABV AND LLVL DIR SHEAR HV PERMITTED EMBEDDED
MESOSCALE CLUSTERS WITHIN SYNOPTIC SCALE SYSTEM. THESE CLUSTERS
LOW TOPPED...AND EXHIBITING CHARACTERISTICS SIMLR TO A TROPICAL
SYSTEM. CANNOT RULE OUT LCL DMGG WNDS AND/OR A BRIEF TOR. HWVR...
THE BIG STORY FOR THE AFTN REMAINS RAFL RATES.

A LINE OF CNVCTN HAS FIRED UP IN THE UPR OH VLY SWD TO ERN KY/TN
ALONG THE ACTUAL COLD/OCCLUDED FNT. CAPE/SHEAR IN THIS AREA MUCH
BETTER. CAPE RESPECTABLE IN WRN CWFA AS WELL...WHERE ANOTHER
LINE SEGMENT HAS DVLPD. WHILE THUNDER XPCTD...AM NOT CERTAIN ON A
WIDESCALE SVR OUTBREAK. WL BE LOSING THE HEATING BY THE TIME THE
SHEAR ARRIVES. SO...POPS WL BE MAINTAINED WELL INTO THE NGT...BUT
WL BE SCALING BACK ON TSRA POTL OVNGT.
&&

.SHORT TERM /3 AM WEDNESDAY MORNING THROUGH FRIDAY/...
CWA WILL BE POST-FRONTAL WEDNESDAY...BUT UPPER TROUGH AXIS STILL HAS
TO PASS THROUGH. THIS COMBINED WITH COOLER AIR ALOFT WILL RESULT IN
SOME CLOUDS BUT CWA SHOULD BE DRY SAVE FOR A FEW SHOWERS ACROSS THE
POTOMAC HIGHLANDS...MAINLY THE WESTERNS SLOPES.

AFTR THAT THINGS SHOULD BE CALMING DOWN NICELY. THE CD FNT SHOLD
BE WELL E OF THE AREA WED NGT. A PRES GRAD COULD PERSIST WED NGT
KEEPING IT BRZY...OR DECOUPLING COULD OCCUR AND WINDS GO LGT.
OUTSIDE OF THE CITIES/ALONG THE BAY LOWS WL BE IN THE 50S WED NGT.

NO PROBS FORESEEN THU/FRI. HIGH PRES OVR THE AREA.
&&

.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
HIGH PRESSURE AND ASSOCIATED DRY AIRMASS BUILDING ACROSS CWA FRIDAY.
PRECIPITATION DEVELOPING ALONG COLD FRONT ACROSS SOUTHWEST NEW YORK/
NORHTEAST PENNSYLVANIA SATURDAY WILL MOVE SOUTHWARD SUNDAY. SURFACE LOW
DEVELOPING OVER MID MISSISSIPPI VALLEY SUNDAY WILL MOVE NORTHEAST
BRINGING MOISTURE INTO CWA MONDAY. BEST OPPORTUNITY FOR SHOWERS/
THUNDERSTORMS WILL OCCUR ON SUNDAY AND MONDAY.
&&

.AVIATION /19Z TUESDAY THROUGH SUNDAY/...
WIDESPREAD FLGT RESTRICTIONS ATTM...THO BREAKS OF VFR SHUD BECOME
MORE NMRS FOR THE AFTN PUSH. BWI/MTN MOST IMPACTED BY HVY RA
STILL...AND THE LULL WL BE DELAYED AND BRIEFER THERE. WL HV A CPL
MORE ROUNDS OF SHRA/TSRA LT TAFTN-TNGT. RESTRICTIONS FROM EACH SHUD BE
BRIEF. WL NEED TO ADD TIMING IN TAFS VIA TEMPS GROUPS ONCE ITS CLEAR.

VFR CONDS XPCTD WED NGT STRAIGHT THRU TO THE WKND.

&&

.MARINE...
SLY FLOW TDA OUTSIDE OF STRONG SHRA. INFLOW TO SHRA MAY BE NELY.
EITHER WAY...NMRS REPORTS IN EXCEDD OF SCA CRITERIA. SCA IN EFFECT
ALL WATERS REST OF TDA. IN ADDITION...SPECIAL MARINE WRNGS WL NEED
TO BE ISSUED INVOF STORMS.

COLD FRONT MOVES THROUGH OVERNIGHT. NOT SURE HOW STRONG THE NW
PUSH IS BEHIND THE FRONT FOR WEDNESDAY. CAN/T RULE OUT A SCA
BECOMING NECESSARY BUT CONFIDENCE TOO LOW ATTM.

IN THE XTND PD...PRIMARILY A CALM PD ON THE WATERS. IT IS PSBLTHAT
SCA LVL GUSTS MAY CONT ON THE BAY...BUT THU AND FRI LOOKING LK
GOOD DAYS TO BE ON THE WATERS. AS OF NOW THIS TREND IS XPCTD TO
CONT INTO THE WKND.

&&

.TIDES/COASTAL FLOODING...
ANOMALIES HV JUMPED UP TO 1.5 FT TAFTN. SO EVEN THOUGH THE PM
TIDE IS A LITTLE LOWER ASTRONOMICALLY...THE RESULTS PROVING TO
BE ABOUT THE SAME AS THIS MORNING...IF NOT GREATER.

BLOWOUT NWLY WINDS WILL BE ARRIVING AT THE SAME TIME AS THE AM
TIDE CYCLE WED MORNING. SUSPECT THE BAY ANNAPOLIS SWD WL NEED TO
HV THE ADVY EXTENDED FOR ONE MORE CYCLE. FOR BALT HARBOR/HARFORD
AND THE UPPER TIDAL POTOMAC...ITLL BE A CLOSE CALL.

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...FLASH FLOOD WATCH UNTIL 2 AM EDT WEDNESDAY FOR DCZ001.
     COASTAL FLOOD ADVISORY UNTIL 2 AM EDT WEDNESDAY FOR DCZ001.
MD...FLASH FLOOD WATCH UNTIL 2 AM EDT WEDNESDAY FOR MDZ005>007-
     009>011-013-014-016.
     COASTAL FLOOD ADVISORY UNTIL 2 AM EDT WEDNESDAY FOR MDZ007-011-
     013.
     COASTAL FLOOD ADVISORY UNTIL 10 PM EDT THIS EVENING FOR MDZ014-
     017-018.
VA...FLASH FLOOD WATCH UNTIL 2 AM EDT WEDNESDAY FOR VAZ052>057.
     COASTAL FLOOD ADVISORY UNTIL 2 AM EDT WEDNESDAY FOR VAZ054.
WV...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL MIDNIGHT EDT TONIGHT FOR ANZ532>534-
     537-540>543.
     SMALL CRAFT ADVISORY UNTIL 6 PM EDT THIS EVENING FOR ANZ530-
     531-535-536-538-539.

&&

SYNOPSIS...HTS
NEAR TERM...HTS
SHORT TERM...HTS/BPP/WOODY!
LONG TERM...CEM
AVIATION...HTS/BPP/WOODY!
MARINE...HTS/BPP/WOODY!
TIDES/COASTAL FLOODING...HTS

HAZARDOUS WEATHER OUTLOOK...UPDATED
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
1216 PM EDT TUE AUG 12 2014

ANZ530>543-DCZ001-MDZ006-007-011-013-014-016>018-VAZ052>057-
130930-
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-
1216 PM EDT TUE AUG 12 2014

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...THIS AFTERNOON AND TONIGHT

A FLASH FLOOD WATCH IS IN EFFECT UNTIL LATE TONIGHT FOR PORTIONS
OF MARYLAND...THE DISTRICT OF COLUMBIA AND VIRGINIA. PERIODS OF SHOWERS
AND THUNDERSTORMS WITH AREAS OF HEAVY RAINFALL WILL BE POSSIBLE
WHICH MAY RESULT IN POTENTIAL FLOODING ALONG THE INTERSTATE 95
CORRIDOR.

SOME THUNDERSTORMS DURING THE LATE AFTERNOON AND EVENING MAY
ALSO PRODUCE DAMAGING WIND GUSTS. AN ISOLATED TORNADO IS ALSO
POSSIBLE.

A COASTAL FLOOD ADVISORY IS IN EFFECT FOR THE WESTERN SHORE OF THE
MARYLAND CHESAPEAKE BAY AND ALONG THE UPPER TIDAL POTOMAC RIVER
THROUGH THE HIGH TIDE CYCLE THIS AFTERNOON AND EVENING. TIDAL
FLOODING MAY LINGER INTO PREDAWN WEDNESDAY MORNING FOR SAINT
MARYS...CALVERT...AND ANNE ARUNDEL COUNTIES.

A SMALL CRAFT ADVISORY REMAINS IN EFFECT FOR THE MARYLAND
CHESAPEAKE BAY AND TIDAL POTOMAC RIVER TODAY. THE SMALL CRAFT
ADVISORY CONTINUES OVER A PORTION OF THE WATERS THIS EVENING.

.DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY

A SMALL CRAFT ADVISORY MAY BE NECESSARY OVER A PORTION OF THE
WATERS WEDNESDAY.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION MAY BE NEEDED THIS AFTERNOON AND EVENING.

MDZ003>005-009-010-501-502-VAZ025>031-036>040-042-050-051-501>504-
WVZ050>053-055-501>506-130930-
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-
1216 PM EDT TUE AUG 12 2014

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...THIS AFTERNOON AND TONIGHT

A FLASH FLOOD WATCH IS IN EFFECT UNTIL LATE TONIGHT FOR PORTIONS
OF MARYLAND...THE DISTRICT OF COLUMBIA AND VIRGINIA. PERIODS OF SHOWERS
AND THUNDERSTORMS WITH AREAS OF HEAVY RAINFALL WILL BE POSSIBLE
WHICH MAY RESULT IN POTENTIAL FLOODING PRIMARILY EAST OF THE BLUE
RIDGE AND ACROSS THE INTERSTATE 95 CORRIDOR.

SOME THUNDERSTORMS DURING THE AFTERNOON AND EVENING MAY ALSO PRODUCE
DAMAGING WIND GUSTS. AN ISOLATED TORNADO IS ALSO POSSIBLE.

.DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY

NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION MAY BE NEEDED THIS AFTERNOON AND EVENING.

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
154 PM EDT TUE AUG 12 2014

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

1245 PM     FLASH FLOOD      1 ESE LAUREL            39.10N  76.85W
08/12/2014                   PRINCE GEORGES     MD   BROADCAST MEDIA

            WATER UP TO THE HEADLIGHTS OF CARS OFF BOWIE ROAD EAST
            OF ROUTE 1. ROAD CLOSED.

&&

EVENT NUMBER LWX1400922

JE

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
221 PM EDT TUE AUG 12 2014

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0158 PM     FLASH FLOOD      BWI AIRPORT             39.17N  76.67W
08/12/2014                   ANNE ARUNDEL       MD   PUBLIC

            WATER FLOWING OVER ROADWAYS AND UP TO THE HEADLIGHTS OF
            CARS NEAR BWI AIRPORT.

&&

EVENT NUMBER LWX1400923

JE

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
224 PM EDT TUE AUG 12 2014

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0157 PM     FLASH FLOOD      BWI AIRPORT             39.17N  76.67W
08/12/2014                   ANNE ARUNDEL       MD   PUBLIC

            FLOODING REPORTED AT THE MAINTENANCE SHOP AT BWI.

&&

EVENT NUMBER LWX1400924

JE

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
245 PM EDT TUE AUG 12 2014

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0229 PM     FLASH FLOOD      2 S FELLS POINT         39.25N  76.58W
08/12/2014                   BALTIMORE CITY     MD   DEPT OF HIGHWAYS

            BALTIMORE HARBOR TUNNEL CLOSED DUE TO FLOODING.

&&

EVENT NUMBER LWX1400925

JE

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
248 PM EDT TUE AUG 12 2014

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0225 PM     FLASH FLOOD      LANSDOWNE               39.24N  76.66W
08/12/2014                   BALTIMORE          MD   DEPT OF HIGHWAYS

            MARYLAND 295 FLOODED AND CLOSED BETWEEN THE BALTIMORE
            BELTWAY AND WESTPORT.

&&

EVENT NUMBER LWX1400926

JE

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
300 PM EDT TUE AUG 12 2014

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0253 PM     FLASH FLOOD      ARBUTUS                 39.24N  76.69W
08/12/2014                   BALTIMORE          MD   PUBLIC

            AT LEAST SIX INCHES OF WATER FLOWING ACROSS BENSON
            AVENUE IN ARBUTUS.

&&

EVENT NUMBER LWX1400927

JE