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000
FXUS61 KLWX 141906
AFDLWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
306 PM EDT FRI JUN 14 2013

.SYNOPSIS...
AN UPPER-LEVEL TROUGH WILL MOVE OFF THE EAST COAST THIS AFTERNOON.
HIGH PRESSURE WILL BUILD OVER THE MID-ATLANTIC TONIGHT BEFORE
SHIFTING OFF THE SOUTHEASTERN STATES COAST SATURDAY NIGHT. A
TROUGH OF LOW PRESSURE WILL APPROACH FROM THE NORTHWEST LATE THIS
WEEKEND AND EARLY NEXT WEEK. HIGH PRESSURE RETURNS BY MIDWEEK.

&&

.NEAR TERM /THROUGH SATURDAY/...
LARGE-SCALE UPPER TROUGH HAS PROGRESSED EWD THRUOUT THE DAY WITH THE
AXIS NOW OVER THE ERN SEABOARD. AFTN WV SAT LOOP DEPICTS SHORTWAVE
ENERGY ROTATING AROUND THE BACKSIDE OF THE UPPER TROUGH. COLD POOL
ALOFT COMBINED WITH DAYTIME HEATING HAS PRODUCED ENOUGH INSTABILITY
FOR SCT SHOWERS IN PA. THESE SHOWERS WILL REACH THE MASON-DIXON LINE
LATE THIS AFTN AS THE SHORTWAVE DISTURBANCE MOVES SOUTHWARD. HAVE
ADDED ISO SHOWERS AND SPRINKLES TO THE FCST FOR THE NRN HALF OF THE
CWA. CANNOT RULE OUT A LIGHTNING STRIKE OR PEA-SIZE HAIL REPORT
WITH SOME OF THE STRONGER CELLS LATE THIS AFTN. THIS ACTIVITY SHOULD
BE WEAKENING TOWARD SUNSET WITH THE LOSS OF DAYTIME HEATING.

CANADIAN HIPRES BUILDS OVERHEAD TNGT. UNDER MAINLY CLEAR SKIES AND
LGT WINDS...RADIATIONAL FOG LIKELY TO DEVELOP IN THE RIVER VLYS.
MIN TEMPS WILL RANGE FROM THE UPPER 40S IN THE ALLEGHENY FRONT TO
LOWER 60S IN THE CITIES AND ALONG THE WRN SHORE.

THE CENTER OF HIPRES SHIFTS TOWARD THE CAROLINA COAST ON SAT. FEW
FAIR-WX CU ON SAT WILL DO LITTLE TO HIDE THE SUN. MAX TEMPS ABOUT 5
DEGREES WARMER THAN TDA...UPPER 70S TO LOWER 80S.

&&

.SHORT TERM /SATURDAY NIGHT THROUGH SUNDAY/...
SWLY FLOW DEVELOPS SAT NGT AS THE HIGH MOVES OFF THE COAST AND
LOPRES APPROACHES FROM THE GREAT LAKES. SAT NGT SHOULD BE DRY
ALTHOUGH A FEW MID-HI CLOUDS SPREAD INTO THE WRN HIGHLANDS.

WITH FAST ZONAL FLOW ALOFT...THE NRN STREAM LOW WILL STAY NORTH OF
THE AREA AS IT MOVES INTO THE NORTHEAST STATES. ATTENDANT SFC TROUGH
IS FCST TO CROSS THE AREA FROM THE NW SUN AFTN. THIS WILL PROVIDE
THE FOCUS FOR SHOWERS AND PERHAPS A FEW TSTMS DURING THE PEAK
HEATING HRS. BASED ON RECENT MODEL PERFORMANCE...FAVORED THE LOWER
DEWPOINTS PER THE GFS /MID 60S/ VS THE NAM /LOW 70S/...WHICH YIELDS
WEAK INSTABILITY PROFILES.

&&

.LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
CONVERGENCE ZONE AND ASSOCIATED PRECIP PERSISTS ACROSS THE AREA INTO
MONDAY NIGHT UNTIL LOW PRESSURE OVER THE GREAT LAKES FINALLY PUSHES
THE COLD FRONT INTO THE SRN MID-ATLANTIC. DIURNALLY DRIVEN PRECIP
AND INTENSITY OF THUNDERSTORMS THROUGH THIS TIME. NEAR NORMAL MAX
TEMPS DUE TO CLOUD COVER...AND ABOVE NORMAL MIN TEMPS FOR THE SAME
REASON.

ANOTHER ROUND OF SFC HIGH PRESSURE TUESDAY THROUGH THURSDAY WITH A
RETURN OF SLIGHTLY BELOW NORMAL TEMPERATURES AND DRY CONDITIONS.

&&

.AVIATION /19Z FRIDAY THROUGH WEDNESDAY/...
NWLY WINDS HAVE SUBSIDED AND BACKED A BIT THIS AFTN WITH GUSTS
GENERALLY 15 KT OR LESS. LGT WINDS TNGT WITH HIPRES OVERHEAD.
PATCHY BR MAY BRIEFLY REDUCE VSBYS TO MVFR AT CHO/MRB ERY SAT
MRNG.

VFR SATURDAY INTO SUNDAY MRNG AS HIGH PRESSURE BUILDS SOUTHEAST
ACROSS THE SOUTHERN MID-ATLANTIC. NWLY FLOW AROUND 10 KT SATURDAY
BECOMING 5-10 KT SWLY SAT NGT/SUN MRNG.

SHRA AND ISO TSRA POSSIBLE AHEAD OF A SFC TROUGH THAT MOVES THRU
THE TERMINALS SUN AFTN. AN UNSETTLED PERIOD POSSIBLE THRU MONDAY
NIGHT WITH DIURNALLY DRIVEN CONVECTIVE STORMS.

&&

.MARINE...
N-NW WINDS HAVE SUBSIDED AS EXPECTED BUT ARE STILL GUSTING TO 20
KT. SCA REMAINS IN EFFECT THRU THE LATE AFTN. WINDS SHOULD REMAIN
BELOW SCA CRITERIA TONIGHT...BUT WILL BE CLOSE TO CRITERIA IN THE
OPEN WATERS OF THE BAY.

NWLY FLOW 10 TO 15 KT SATURDAY BECOMES SWLY SATURDAY NIGHT. CHANNELING
LATE LOOKS TO GUST AROUND 20 KT INTO SUNDAY. SCA LIKELY. ACTIVE
WEATHER SUNDAY EVENING THROUGH MONDAY NIGHT AS A COLD FRONT SAGS
THROUGH THE AREA.

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...NONE.
VA...NONE.
WV...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 PM EDT THIS EVENING FOR
     ANZ530>543.

&&

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