Severe Thunderstorm Warning 4, NWS Baltimore/Washington

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
314 PM EDT TUE APR 22 2014

.SYNOPSIS...
A COLD FRONT WILL PASS THROUGH THIS EVENING. HIGH PRESSURE RETURNS
FOR WEDNESDAY AND THURSDAY BEFORE MOVING OFF THE COAST FRIDAY. A
COLD FRONT IS EXPECTED TO PASS THROUGH THE AREA SATURDAY.

&&

.NEAR TERM /THROUGH WEDNESDAY/...
18Z SFC ANALYSIS SHOWS A 998 MB LOW JUST NORTH OF THE ADIRONDACKS.
A COLD FRONT EXTENDS TO THE SW OF THE LOW IN CENTRAL NY-WRN PA AND
BACK TOWARD THE OH RVR.

A BAND OF SHOWERS ASSOCIATED WITH A PRE-FRONTAL TROUGH AND MOISTURE
PLUME WILL CONTINUE TO PROGRESS EWD THRU THE I-95 CORRIDOR BEFORE
MOVING EAST OF THE CHSPK BAY LATE THIS AFTN. FARTHER UPSTREAM...A
NARROW LINE OF CONVECTION HAS DEVELOPED ALONG THE COLD FRONT NEAR
PIT. HI-RES REFLECTIVITY MODELS THAT CAPTURED THIS CONVECTION
SIMULATE THIS LINE TO REACH THE ALLEGHENY FRONT BY 4 OR 5 PM BEFORE
MOVING SEWD THRU PORTIONS OF THE CWA DURING THE ERY EVE. KEPT POPS
HIGHEST ACROSS NRN PORTIONS OF THE CWA WHERE THE BEST FORCING
ASSOCIATED WITH THE UPPER SHORTWAVE TROUGH WILL BRUSH. TSTM
POTENTIAL IS LOW WITH PRE-FRONTAL SHOWERS AND CLOUD COVER LIMITING
DESTABILIZATION.

THE COLD FRONT WILL MOVE THRU THE AREA THIS EVE. GUSTY NW WINDS WILL
USHER IN COLDER AIR BEHIND THE COLD FRONT. CLEARING SKIES FROM WEST
TO EAST TNGT AS WELL...ALTHOUGH STRATOCU WILL KEEP SKIES MOSTLY
CLOUDY ALONG THE WRN SIDE OF THE ALLEGHENY FRONT DUE TO UPSLOPE FLOW.
WINDS WILL STAY MIXED SO ADVECTION WILL BE MAIN SOURCE OF AIRMASS
COOLING TNGT. MIN TEMPS TNGT RANGE FROM THE NEAR 30F IN THE WRN
HIGHLANDS TO MID AND UPPER 40S EAST OF THE BLUE RIDGE.

HIPRES BUILDS IN FROM THE GREAT LAKES ON WED. PRESSURE RISES WILL
BE ACCOMPANIED BY BREEZY NW WINDS THAT GUST 30-40 MPH DURING THE
DAY. COLD AIRMASS WILL BE MODERATED A BIT BY THE HIGH SUN ANGLE.
FCST WEIGHTED TOWARD THE WARMER BIAS CORRECT MARV GUIDANCE WITH
SUNNY SKIES AND DOWNSLOPING FLOW. MAX TEMPS GENERALLY RANGE FROM
THE MID 50S TO MID 60S EXCEPT FOR COOLER HIGHS IN THE 40S ALONG
HIGHER ELEVATIONS RIDGES.

&&

.SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY/...
SFC LOW PRESSURE SHOULD BE MOVING TOWARDS NEWFOUNDLAND WED NIGHT AND
HIGH PRESSURE WILL MOVE INTO THE MID ATLANTIC FROM THE WEST. THE
PRESSURE GRADIENT RESPONSIBLE FOR THE GUSTY WINDS WEDNESDAY WILL
DEPART TO OUR EAST WED EVENING. TEMPS WILL REACH THE LOW 30S WEST OF
THE BLUE RIDGE AS CLEARING AND CALM WINDS WILL ALLOW FOR TEMPS TO
DROP. ELSEWHERE...MID TO UPPER 30S EXPECTED TO AROUND 40 IN THE
METROS.

UPPER LEVEL RIDGING WILL MOVE OVERHEAD THURSDAY RESULTING IN A SUNNY
DAY WITH TEMPS IN THE 60S. A WEAK COLD FRONT ASSOCIATED WITH LOW
PRESSURE ACROSS THE NRN PLAINS WILL APPROACH THE REGION. CLOUDS WILL
INCREASE FROM THE WEST THURSDAY AS HIGH PRESSURE WILL MOVES OFF THE
COAST BY THURSDAY NIGHT. A BRIEF PERIOD OF RETURN FLOW WILL
INCREASE ACROSS THE REGION THURSDAY NIGHT AND FRIDAY. TEMPS WILL
REACH 70-75 DEGREES FRIDAY AFTERNOON. THE WEAK COLD FRONT WILL CROSS
THE APPALACHIANS FRIDAY AFTERNOON AND SHOWERS ARE EXPECTED TO MOVE
AHEAD OF THE FRONT.

&&

.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
AN UPPER-LEVEL TROUGH...ACCOMPANIED BY A SECONDARY COLD FRONT AND
STRONG PRESSURE SURGE/COLD ADVECTION WILL MOVE THROUGH THE AREA TO
BEGIN THE WEEKEND. THE BOUNDARY LOOKS MOISTURE STARVED...SO ANY
ISOLATED SHOWER ACTIVITY WOULD REMAIN CONFINED TO AREAS ALONG THE
MASON-DIXON LINE CLOSEST TO THE FORCING FROM THE SHORTWAVE TROUGH
SATURDAY. THUS SLIGHT CHANCE POPS HAVE BEEN CONFINED TO THESE AREAS.

AT THE MOMENT...THE MEDIUM RANGE GUIDANCE HAS COME INTO BETTER WITH
THE TIMING AND STRENGTH OF THE FRONT. STRONG AND GUSTY WINDS ARE
APPEARING INCREASINGLY LIKELY FOR SATURDAY...ESPECIALLY CONSIDERING
THE STRONGEST WINDS ACCOMPANYING THE PRESSURE SURGE WILL OCCUR
DURING PEAK HEATING WHEN LAPSE RATES ARE STEEPEST AND MIXING DOWN
HIGHER WIND GUSTS WOULD BE EASIEST.

WINDS DIMINISH SATURDAY NIGHT INTO SUNDAY MORNING AS AN AREA OF HIGH
PRESSURE NOSES OVER THE REGION...BUT ITS STAY OVER OUR AREA IS
SHORT-LIVED AS A LARGE AND SLOW-MOVING AREA OF LOW PRESSURE APPROACH
FROM THE WEST BRINGING A RETURN TO UNSETTLED WEATHER EARLY NEXT WEEK.

&&

.AVIATION /19Z TUESDAY THROUGH SUNDAY/...
LGT SHRA AHEAD OF THE FRONT HAS SHIFTED EAST OF IAD AND WILL IMPACT
DCA/BWI/MTN THRU ABOUT 21Z. INTENSITY HAS BEEN SO LGT THAT NO FLGT
RESTRICTION WERE ACCOMPANIED WITH THIS ACTIVITY. WINDS HAVE SHIFTED
OUT OF THE WEST AS THESE SHOWERS AND ASSOCIATED SFC TROUGH MOVE THRU
BUT WILL BE LGT UNTIL THE COLD FRONT MOVES THRU THIS EVE. ANY TSRA
WITH THE FRONT THIS EVE WILL BE LOCALIZED AND PROBS TOO CHANCE TOO
LOW TO INCLUDE IN TAFS. NW WINDS 10-15 KT WILL GUST TO 25 KT BEHIND THE
FRONT THRU MUCH OF TNGT. NW WINDS INCREASE ON WED DUE TO DAYTIME
MIXING WITH GUSTS TO 35 KT POSSIBLE. VFR ON WED.

NW FLOW WILL SUBSIDE WED NIGHT. HIGH PRESSURE MOVES INTO THE REGION
THURSDAY BEFORE MOVING OFF THE COAST AHEAD OF A WEAK COLD FRONT
THURSDAY NIGHT. SHOWERS MAY CROSS THE TERMINALS FRIDAY.

MODERATE CONFIDENCE IN VFR CONDITIONS AND WESTERLY WINDS AROUND 10
KNOTS FRIDAY NIGHT...WITH MODERATE CONFIDENCE IN WINDS INCREASING TO
BETWEEN 15 AND 20 KNOTS WITH GUSTS UP TO 30 KNOTS DURING THE DAY
SATURDAY.

&&

.MARINE...
SCA REMAINS IN EFFECT FOR THE WATERS THRU TNGT. SCA LVL REPORTS ONLY
ISOLATED THUS FAR BUT ANY SHOWERS MOVING THRU COULD DRAG DOWN
LOCALLY HIGHER WINDS. WINDS BECOME GUSTY FOLLOWING A COLD FROPA
DURING THE MID TO LATE EVE AND INTO THE OVNGT. WIDESPREAD SCA
CONDITIONS EXPECTED BEHIND THE FRONT. A GALE WARNING IS IN EFFECT
WEDNESDAY FOR ALL OF THE WATERS WITH GUSTS UP TO 35 KT EXPECTED
DURING THE DAY. THE GALE WARNING MAY BE ABLE TO BE DOWNGRADING
SOMETIME DURING THE AFTN AS THE PRESSURE GRADIENT AND ASSOCIATED
WIND FIELD WEAKENS A BIT.

NORTHWEST WINDS WILL CONTINUE ON THE WATERS WEDNESDAY NIGHT AND A
SCA IS IN EFFECT. WINDS WILL SUBSIDE FROM WEST TO EAST THEREFORE THE
SCA FOR THE UPPER TIDAL POTOMAC WILL DROP LATE WED NIGHT. WINDS WILL
CONTINUE TO CAUSE SCA CONDITIONS ACROSS THE BAY INTO THURSDAY. A SCA
MAY BE EXTENDED FOR THURSDAY. HIGH PRESSURE MOVES INTO THE REGION
THURSDAY AND THURSDAY NIGHT. SOUTHERLY FLOW WILL INCREASE ACROSS THE
WATERS FRIDAY.

A PERIOD OF HIGH-END SMALL CRAFT ARE EXPECTED BEHIND A STRONG BUT
MOISTURE-STARVED COLD FRONT SATURDAY. WINDS DIMINISH THROUGH THE
NIGHT SATURDAY AND LIKELY DROP BELOW SMALL CRAFT LEVELS DURING THE
DAY SUNDAY.

&&

.FIRE WEATHER...
A COLD FRONT WILL PASS THROUGH THE AREA THIS EVENING AND GUSTY
NORTHWEST WINDS ARE EXPECTED BEHIND THE COLD FRONT WEDNESDAY. A DEEP
MIXING LAYER WILL ALLOW FOR DRIER AIR TO MIX DOWN...CAUSING LOW
RELATIVE HUMIDITY VALUES DURING THE LATE MORNING THROUGH THE
AFTERNOON. THE COMBINATION OF GUSTY WINDS...LOW FUEL MOISTURE AND
LOW RELATIVE HUMIDITY WILL ENHANCE THE THREAT FOR THE SPREAD OF
WILDFIRES WEDNESDAY. AFTER COORDINATION WITH STATE OFFICIALS AND
SURROUNDING WFOS...A FIRE WEATHER WATCH WAS ISSUED.

&&

.TIDES/COASTAL FLOODING...
POSITIVE TIDAL ANOMALIES REMAIN STEADY AROUND THREE-QUARTERS OF A
FOOT THIS AFTN. SLY WINDS WILL BECOME WLY WITHIN THE NEXT FEW HRS
AND ANOMALIES WILL DECREASE SUBSEQUENTLY.

GUSTY NORTHWEST WINDS WILL DEVELOP TONIGHT AND CONTINUE THROUGH
WEDNESDAY. BLOWOUT TIDES ARE EXPECTED WEDNESDAY.

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...FIRE WEATHER WATCH FROM WEDNESDAY MORNING THROUGH WEDNESDAY
     EVENING FOR DCZ001.
MD...FIRE WEATHER WATCH FROM WEDNESDAY MORNING THROUGH WEDNESDAY
     EVENING FOR MDZ003>007-009>011-013-014-016>018-502.
VA...FIRE WEATHER WATCH FROM WEDNESDAY MORNING THROUGH WEDNESDAY
     EVENING FOR VAZ025>031-036>040-042-050>057-501-502-504.
WV...FIRE WEATHER WATCH FROM WEDNESDAY MORNING THROUGH WEDNESDAY
     EVENING FOR WVZ050>053-055-502-504-506.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 AM EDT WEDNESDAY FOR ANZ530>543.
     SMALL CRAFT ADVISORY FROM 6 PM WEDNESDAY TO 6 AM EDT THURSDAY
     FOR ANZ530>534-537>543.
     GALE WARNING FROM 6 AM TO 6 PM EDT WEDNESDAY FOR ANZ530>543.
     SMALL CRAFT ADVISORY FROM 6 PM WEDNESDAY TO MIDNIGHT EDT
     WEDNESDAY NIGHT FOR ANZ535-536.

&&

SYNOPSIS...JRK
NEAR TERM...JRK
SHORT TERM...HAS
LONG TERM...DFH
AVIATION...JRK/HAS/DFH
MARINE...JRK/HAS/DFH
FIRE WEATHER...JRK
TIDES/COASTAL FLOODING...JRK

HAZARDOUS WEATHER OUTLOOK...UPDATED
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
235 PM EDT TUE APR 22 2014

ANZ530>543-DCZ001-MDZ006-007-011-013-014-016>018-VAZ052>057-
231000-
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-
235 PM EDT TUE APR 22 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 SMALL CRAFT ADVISORY IS IN EFFECT FOR THE WATERS THROUGH
TONIGHT.

.DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY

A FIRE WEATHER WATCH IS IN EFFECT WEDNESDAY FROM THE LATE MORNING
TO THE EARLY EVENING. THE COMBINATION OF GUSTY WINDS...LOW
RELATIVE HUMIDITY AND LOW FUEL MOISTURE WILL ENHANCE THE THREAT
FOR THE SPREAD OF WILDFIRES ACROSS THE OUTLOOK AREA.

A GALE WARNING IS IN EFFECT FOR THE WATERS WEDNESDAY. A SMALL
CRAFT ADVISORY IS IN EFFECT FOR THE WATERS WEDNESDAY EVENING WHICH
CONTINUES OVERNIGHT FOR THE LOWER TIDAL POTOMAC RIVER AND THE
MARYLAND CHESAPEAKE BAY.

SMALL CRAFT ADVISORIES WILL LIKELY BE NEEDED FOR PORTIONS OF THE
WATERS THURSDAY AND SATURDAY.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION IS NOT EXPECTED.

MDZ003>005-009-010-501-502-VAZ025>031-036>040-042-050-051-501>504-
WVZ050>053-055-501>506-231000-
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-
235 PM EDT TUE APR 22 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

NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

.DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY

A FIRE WEATHER WATCH IS IN EFFECT WEDNESDAY FROM THE LATE MORNING
TO THE EARLY EVENING. THE COMBINATION OF GUSTY WINDS...LOW
RELATIVE HUMIDITY AND LOW FUEL MOISTURE WILL ENHANCE THE THREAT
FOR THE SPREAD OF WILDFIRES ACROSS MUCH OF THE OUTLOOK AREA.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION IS NOT EXPECTED.