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-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KLWX 132007 AAA
AFDLWX

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
407 PM EDT MON MAY 13 2013

.SYNOPSIS...
AN UPPER TROUGH WILL MOVE EAST OF THE REGION TONIGHT WHILE SURFACE
HIGH PRESSURE BUILDS OVER THE REGION. THE HIGH WILL MOVE OFFSHORE
TUESDAY AFTERNOON THROUGH EARLY WEDNESDAY AS A WARM FRONT
ADVANCES NORTHEASTWARD INTO THE MID-ATLANTIC STATES. A COLD FRONT
WILL APPROACH THE REGION LATE WEDNESDAY...BUT STALL OUT THROUGH
THE END OF THE WEEK.

&&

.NEAR TERM /THROUGH TUESDAY NIGHT/...

-- Changed Discussion --
SFC HIPRES JUST WEST OF THE APPALACHIANS WILL CONTINUE TO BUILD
EWD TOWARD THE ERN SEABOARD TNGT. LATEST WATER VAPOR SATELLITE
LOOP SHOWS AN UPPER LOW OVER QUEBEC WHILE A VORT MAX ROTATES
TOWARD THE BASE OF THE UPPER TROUGH AND ACROSS THE MID-ATLANTIC
REGION THIS AFTN AND EVE. DEEP MIXING IS OCCURRING DURING THE PEAK
HEATING HRS AS COLD POOL ALOFT ASSOCIATED WITH THE TROUGH MOVES
IN. EVEN WITH STEEP LOW- AND MID-LVL LAPSE RATES...MOISTURE IS
SCARCE /SFC DEWPOINTS IN THE 20S/ AND INSTABILITY IS WEAK. BASED
ON LOCATION OF BEST LIFT/MOISTURE...POPS ARE HIGHEST OVER THE
MTS...CENTRAL VA AND LWR SRN MD...BUT STILL ONLY 30 PERCENT.
SPRINKLES POSSIBLE ELSEWHERE. GIVEN INVERTED V SOUNDING...SHOWERS
CAPABLE OF TRANSPORTING 30-35 MPH GUSTS DOWN TO THE SFC.

THE CENTER OF THE HIGH WILL SHIFT EWD TOWARD THE POTOMAC HIGHLANDS
OVNGT. THIS PATTERN FAVORS THE BEST RADIATIONAL COOLING CONDITIONS
TO OCCUR ACROSS THE WRN HALF OF THE CWA. THE FREEZE WATCH HAS BEEN
UPGRADED TO A WARNING WEST OF THE BLUE RIDGE AND A FROST ADVISORY
WAS ISSUED FOR THE COUNTIES ALONG THE BLUE RIDGE. FARTHER EAST
TOWARD I-95...WILL HOLD OFF ON A FROST ADVISORY SINCE THERE IS DOUBT
THAT WINDS DECOUPLE FULLY WITH RESIDUAL CAA AND THE HIGH STILL
BUILDING IN FROM THE WEST.

HIPRES MOVES OFFSHORE TUE AFTN...RESULTING IN A LGT RETURN FLOW
DEVELOPING OVER THE AREA. WAA LATE IN THE DAY WILL PROMOTE WARMER
TEMPS TDA THAN YDA...ALTHOUGH INCREASING CLOUD COVER WILL LIMIT THE
EXTENT OF WARMING A BIT. MAX TEMPS TUE GENERALLY IN THE 60S.
-- End Changed Discussion --

&&

.SHORT TERM /WEDNESDAY THROUGH THURSDAY/...
-- Changed Discussion --
UPPER DISTURBANCE AND FRONTAL BOUNDARY WILL AID IN THE DEVELOPMENT
OF SCATTERED SHOWERS AND THUNDERSTORMS BOTH WEDNESDAY AND
THURSDAY. SOME OF THE STORMS COULD BE STRONG. TEMPERATURES WILL
FINALLY MODERATE INTO THE 70S AND 80S...MORE TYPICAL FOR MID MAY.
-- End Changed Discussion --

&&

.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
-- Changed Discussion --
HIGH PRESSURE AND MILD CONDITIONS WILL BE IN PLACE TO CLOSE THE
WORKWEEK BUT YET ANOTHER UPPER LEVEL DISTURBANCE WILL APPROACH THE
FORECAST AREA FROM THE WEST ON SATURDAY. THAT WILL HELP TOUCH OFF
ADDITIONAL SHOWER AND THUNDERSTORM CHANCES ESPECIALLY WEST OF THE
METRO AREAS. INCLEMENT CONDITIONS MAY PERSIST ON SUNDAY AND
POSSIBLY MONDAY OF NEXT WEEK.
-- End Changed Discussion --

&&

.AVIATION /20Z MONDAY THROUGH SATURDAY/...
-- Changed Discussion --
VFR CONDITIONS TDA...TNGT AND TUE. W-NW WINDS GUSTING TO 20-25 KT
THIS AFTN WILL DIMINISH TOWARD SUNSET. LGT WINDS OVNGT AND TUE.

MOSTLY VFR CONDITIONS EXPECTED THROUGH THE END OF THE WEEK.
SCATTERED AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS WILL BE
POSSIBLE BEGINNING ON WEDNESDAY INTO THURSDAY AND AGAIN OVER THE
WEEKEND WHICH MAY LOWER CIGS/VSBYS FOR A TIME.
-- End Changed Discussion --

&&

.MARINE...
-- Changed Discussion --
WIDESPREAD SCA CONDITION OCCURRING THIS AFTN. A FEW SPRINKLES OVER
POSSIBLE OVER THE WATERS UNTIL ABOUT SUNSET. N-NW CHANNELING DOWN
THE BAY WILL KEEP WINDS HIGHER TNGT. SCA IN EFFECT FOR THESE
PORTIONS OF THE WATERS THRU ERY TUE MRNG.

SCA CONDITIONS POSSIBLE OVER PORTIONS OF THE WATERS ON WEDNESDAY.
WINDS ARE EXPECTED TO REMAIN BELOW SCA LEVELS THE REMAINDER OF THE WEEK.
-- End Changed Discussion --

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...FREEZE WARNING FROM 2 AM TO 8 AM EDT TUESDAY FOR MDZ003-501-
     502.
     FROST ADVISORY FROM 2 AM TO 8 AM EDT TUESDAY FOR MDZ004-005.
VA...FREEZE WARNING FROM 2 AM TO 8 AM EDT TUESDAY FOR VAZ025>031-
     503-504.
     FROST ADVISORY FROM 2 AM TO 8 AM EDT TUESDAY FOR VAZ036>040-
     042-050-051-501-502.
WV...FREEZE WARNING FROM 2 AM TO 8 AM EDT TUESDAY FOR WVZ050>053-
     055-501>506.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 AM EDT TUESDAY FOR ANZ532>534-537-
     540-541-543.
     SMALL CRAFT ADVISORY UNTIL 7 PM EDT THIS EVENING FOR ANZ535-
     536-538-542.
     SMALL CRAFT ADVISORY UNTIL 2 AM EDT TUESDAY FOR ANZ530-531-539.

&&

$$
SYNOPSIS...KRW
NEAR TERM...JRK
SHORT TERM...KRW
LONG TERM...KRW
AVIATION...JRK/KRW
MARINE...JRK/KRW