Area Forecast Discussion
Issued by NWS Sterling, VA

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000
FXUS61 KLWX 250159
AFDLWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
959 PM EDT THU JUL 24 2014

.SYNOPSIS...
A COLD FRONT WILL CONTINUE TO PUSH INTO THE CAROLINAS TONIGHT. HIGH
PRESSURE WILL BUILD OVERHEAD TONIGHT THROUGH FRIDAY BEFORE MOVING
OFF THE COAST DURING THE WEEKEND. A COLD FRONT WILL PASS THROUGH
THE AREA EARLY NEXT WEEK.

&&

.NEAR TERM /THROUGH FRIDAY/...
AS OF 01Z...RAIN HAS CLEARED THE THE CWA...DRY NRLY FLOW CONTINUES
TO ADVECT INTO THE REGION BEHIND THE COLD FRONT AND DEWPTS HAVE
DROPPED IN THE 50S FOR CNTRL MD...DC...TO PETERSBURG VA...WITH MID
60S SOUTH OF THERE. DEWPTS WILL CONTINUE TO DROP FROM NORTH TO
SOUTH TONIGHT AS THE COLD FRONT MOVES THROUGH THE CAROLINAS.

AN UPPER LEVEL TROUGH AXIS WILL CROSS THE REGION OVERNIGHT AND DRY
AND COOLER CONDITIONS WILL ENSUE. FCST MIN TEMPS A BLEND OF
MAV/MET/SREF AND RANGE FROM THE MID 50S WEST OF THE BLUE RIDGE
AND NORTH OF BALTIMORE TO AROUND 60F IN INLAND AREAS SOUTH/EAST OF
THERE...TO UPR 60S IN URBAN NEAR SHORE LOCALES. RECORD TYING
MIN TEMP FORECAST FOR BALTIMORE (SEE CLIMATE SECTION BELOW). ONE
FACTOR TO LIMIT TEMPS DECLINE IS CLOUDS WHICH ARE PROGRESSING
EAST...BUT MAY NOT CLEAR OUT UNTIL THE TROUGH AXIS PUSHES THROUGH
LATE TONIGHT.

HIGH PRESSURE WILL CENTER OVER THE REGION FRIDAY AFTERNOON...WITH
A LIGHT RETURN FLOW FOR FRIDAY NIGHT. FCST MAX TEMPS A BLEND OF
MAV/MET/GMOS AND ARE IN THE LOW TO MID 80S. A CU FIELD SHOULD
DEVELOP AS MOISTURE ALOFT PERSISTS. A FEW SHOWERS MAY BE POSSIBLE
IN THE CENTRAL FOOTHILLS AS MOISTURE CREEPS INTO THE REGION FRI
AFTERNOON. CONFIDENCE OF SHOWERS IS LOW AT THIS TIME.

&&

.SHORT TERM /FRIDAY NIGHT THROUGH SATURDAY/...
WESTERLY ZONAL FLOW ALOFT WILL CONTINUE INTO SATURDAY AS THE HIGH
MOVES WELL OFF THE EAST COAST. A SHORTWAVE TROUGH MAY CROSS NORTH OF
THE REGION SATURDAY AND SHOWERS AND THUNDERSTORMS MAY BE POSSIBLE
NEAR THE MASON DIXON LINE. A LEE TROUGH IS EXPECTED TO FORM AND MAY
INITIATE THUNDERSTORMS. MOISTURE BEGINS TO POOL INTO THE REGION WITH
INCREASE PWATS AND THETA-E ADVECTION. FCST MAX TEMPS WILL BE IN
THE UPPER 80S.

&&

.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
A TROUGH TO THE EAST OF THE APPALACHIAN MOUNTAINS SATURDAY NIGHT AND
PASSING UPPER LEVEL ENERGY MAY BE ENOUGH TO SPAWN A COUPLE OF
SHOWERS AND THUNDERSTORMS.

THERE IS A BETTER CHANCE FOR HEAVIER SHOWERS AND GUSTY THUNDERSTORMS
SUNDAY AND SUNDAY NIGHT AS THE MAIN UPPER LEVEL FEATURE OVER THE
GREAT LAKES BEGINS TO TREK ITS WAY EASTWARD...ALLOWING A SURFACE LOW
PRESSURE TO DEVELOP ALONG THE ALREADY-ESTABLISHED TROUGH OF LOW
PRESSURE ALONG THE SHENANDOAH VALLEY. THE MAIN THREAT FROM THE
THUNDERSTORMS WILL BE DAMAGING WINDS AS LAPSE RATES APPEAR FAVORABLE
AND MID LEVEL AND UPPER LEVELS MAY BE STRONGER THAN RECENT DAYS.

AS THE MAIN UPPER LEVEL STORM MOVES INTO SOUTHEAST CANADA MONDAY
INTO MONDAY NIGHT...ITS ASSOCIATED SURFACE COLD FRONT WILL PUSH TO
THE EAST COAST BY TUESDAY MORNING. AHEAD OF THE FRONT...PERHAPS ONE
FINAL ROUND OF SHOWERS AND THUNDERSTORMS COULD DEVELOP IN THE REGION
MONDAY INTO MONDAY EVENING.

TUESDAY AND WEDNESDAY WILL BE NOTICEABLY DRIER AND COOLER WITH HIGH
PRESSURE BUILDING IN FROM THE WEST.

A GRADUAL RETURN FLOW THURSDAY WILL BRING MOISTURE BACK INTO THE
REGION. HIGH PRESSURE WILL BE OFFSHORE BY THIS TIME. SOME WEAK UPPER
LEVEL ENERGY WILL SLIDE NORTHWARD AND COULD SPAWN A SHOWER OR
THUNDERSTORM IN THE HIGHER TERRAIN.

&&

.AVIATION /02Z FRIDAY THROUGH TUESDAY/...
HIGH PRESSURE WILL MOVE INTO THE REGION TONIGHT AND CENTER OVER
THE AREA FRIDAY. NLY FLOW SHOULD KEEP FOG AT BAY...BUT AREAS THAT
RECEIVED RAIN COULD GET FOG. WENT WITH MVFR VSBYS FOR KCHO AND SEE
A REPORT OF IFR BR ALREADY...WILL HAVE MIDNIGHT SHIFT MONITOR
THIS. VFR CONDITIONS EXPECTED FRIDAY. SOUTHERLY FLOW WILL BEGIN
FRIDAY AFTERNOON AND CONTINUE INTO SATURDAY. SHOWERS AND
THUNDERSTORMS POSSIBLE SATURDAY AFTERNOON.

MVFR OR IFR CONDITIONS COULD DEVELOP WITH SHOWER AND THUNDERSTORM
ACTIVITY SATURDAY NIGHT...MAINLY NEAR CHO AND MRB TERMINALS.
SOUTHERLY WINDS AT 5 TO 10 KNOTS BUT GUSTING 15 TO 20 KNOTS CLOSE
TO THE CHESAPEAKE BAY.

IFR CONDITIONS MAY BE MORE LIKELY AT ANY OF THE TERMINALS SUNDAY
INTO SUNDAY NIGHT WITH HEAVY SHOWERS AND GUSTY THUNDERSTORMS. SOUTH
WINDS BECOMING SOUTHWEST AROUND 10 KNOTS AND GUSTING 15 TO 20 KNOTS
NEAR THE BAY.

VFR CONDITIONS ON MONDAY WITH HIGH PRESSURE BUILDING IN FROM THE
WEST. WINDS BECOMING WEST AT 10 KNOTS WITH AN APPROACHING COLD
FRONT.

&&

.MARINE...
A COLD FRONT WILL CONTINUE TO MOVE THROUGH THE CAROLINAS TONIGHT.
NLY CHANNELING IS INCREASING WITH AN EARLIER SCA FOR POOLES ISLAND
TO DRUM PT BASED ON THE 18Z NAM FORECAST. THE SCA EXPANDS TO
INCLUDE SRN MD WATERS BY 2AM AND CONTINUES UNTIL 8AM. HIGH PRESSURE
MOVES OVER THE WATERS FRIDAY AND WINDS WILL SUBSIDE BEFORE
BECOMING SOUTHERLY BY FRI AFTERNOON. SRLY WINDS WILL CONTINUE INTO
SATURDAY.

SMALL CRAFT ADVISORIES MAY BE NEEDED SATURDAY NIGHT THROUGH MONDAY
WITH GUSTY SOUTHWEST TO WESTERLY WINDS AHEAD OF A COLD FRONT.

&&

.CLIMATE...
59 DEGREES IS THE FORECAST FOR BWI TONIGHT. THE RECORD LOW FOR
THE THREADED BALTIMORE CLIMATE RECORD IS 59...SET IN 2008...
1976...1973...AND 1876.

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...NONE.
VA...NONE.
WV...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 8 AM EDT FRIDAY FOR ANZ531>533-
     539>541.
     SMALL CRAFT ADVISORY FROM 2 AM TO 8 AM EDT FRIDAY FOR ANZ534-
     537-542-543.

&&

$$
SYNOPSIS...BAJ/HAS
NEAR TERM...BAJ/HAS
SHORT TERM...HAS
LONG TERM...KLW
AVIATION...BAJ/HAS/KLW
MARINE...BAJ/HAS/KLW
CLIMATE...BAJ/CEB






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