Area Forecast Discussion
Issued by NWS Sterling, VA

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FXUS61 KLWX 231851
AFDLWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
251 PM EDT WED JUL 23 2014

.SYNOPSIS...
A COLD FRONT FROM THE GREAT LAKES WILL SLOWLY APPROACH THE REGION
THROUGH TONIGHT. THE BOUNDARY WILL SLOWLY PASS THROUGH THE AREA
THURSDAY INTO THURSDAY NIGHT AND HIGH PRESSURE WILL RETURN FOR
FRIDAY. HIGH PRESSURE WILL MOVE OFF THE COAST DURING THE WEEKEND
AND A COLD FRONT WILL PASS THROUGH THE AREA EARLY NEXT WEEK.

&&

.NEAR TERM /THROUGH TONIGHT/...
CYCLONIC FLOW ALOFT CONTINUES AS A UPPER LEVEL TROUGH PERSISTS
ACROSS THE NORTHEASTERN U.S. A BERMUDA HIGH PERSISTS TO THE EAST
WHILE A COLD FRONT APPROACHES THE POTOMAC HIGHLANDS THIS AFTERNOON.
HOT AND HUMID CONDITIONS HAVE LED TO INSTABILITY ON THE ORDER OF
2K-3K J/KG. A CU FIELD HAS DEVELOPED IN AREAS THAT HAVE SEEN FULL
SUNSHINE TODAY. AREAS THAT ARE CLEAR SAW CLOUDS THIS MORNING AND
HAVE NOT YET REACHED THEIR CONVECTIVE TEMP. ALL SHOULD BE FILLED IN
WITH CU SOON. FCST MAX TEMPS TODAY WILL BE IN THE MID 90S RESULTING IN
HEAT INDICES NEAR 100.

A STABLE LAYER AT 650MB PER 12Z IAD RAOB WILL CONTINUE TO WEAKEN AND
SHOWERS AND THUNDERSTORMS ARE EXPECTED TO DEVELOP ACROSS THE OHIO
VALLEY AHEAD OF A COLD FRONT. THIS ACTIVITY WILL MOVE INTO THE
MID-ATLANTIC LATER THIS AFTERNOON AND EVENING. A LEE TROUGH PRESENT
ACROSS THE REGION THIS AFTERNOON MAY CAUSE SHOWERS AND STORMS TO
INITIATE NEAR THE BLUE RIDGE MTNS. DUE TO THE WEAK FORCING
ALOFT...A INVERSION AND WEAK SHEAR PROFILES ACROSS THE MID-ATLANTIC THIS
AFTERNOON... ACTIVITY SHOULD BE SCATTERED AND SUB-SEVERE. LATER
TODAY...AS CONDITIONS BECOME MORE FAVORABLE FOR ORGANIZED
CONVECTION...A FEW STORMS MAY BECOME STRONG TO SEVERE PRODUCING DMG
WINDS. DUE TO THE HEIGHT OF THE FZL...LARGE HAIL IS NOT EXPECTED AT
THIS TIME.

THE COLD FRONT WILL CROSS THE MID ATLANTIC LATE TONIGHT AS THE UPPER
LEVEL TROUGH DIGS INTO THE MIDWEST. SHOWERS AND THUNDERSTORMS MAY
PERSIST OVERNIGHT AS MOISTURE AND UPPER LEVEL FORCING LAG BEHIND THE
COLD FRONT.

&&

.SHORT TERM /THURSDAY THROUGH FRIDAY/...
SHOWERS AND ISOLATED THUNDERSTORMS WILL CONTINUE
THURSDAY. IT WONT BE UNTIL THE TROUGH AXIS CROSSES THE MID ATLANTIC
THURSDAY AFTERNOON WILL DRY CONDITIONS AND CLEARING MOVE INTO THE
AREA FROM THE NORTH. FCST MAX TEMPS ARE AROUND 80 DEGREES THURSDAY.

THE COLD FRONT WILL CONTINUE TO SAG SOUTHWARD THURSDAY NIGHT AND DRY
CONDITIONS WILL PERSIST OVERNIGHT. FCST MIN TEMPS IN THE UPPER 50S
WEST OF THE BLUE RIDGE TO THE LOW 60S NEAR THE I-95 CORRIDOR. HIGH
PRESSURE MOVES INTO THE REGION FRIDAY RESULTING IN CALM AND MOSTLY
SUNNY CONDITIONS.

&&

.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
HIGH PRESSURE WILL KEEP US DRY FRIDAY NIGHT...FROM THE SHENANDOAH
VALLEY TO THE CHESAPEAKE BAY. THERE COULD BE A SHOWER OVER PARTS OF
THE POTOMAC HIGHLANDS OTHERWISE.

UPPER ENERGY WILL MOVE EAST ACROSS OHIO AND PENNSYLVANIA
SATURDAY...BRINGING A CHANCE FOR SHOWERS AND THUNDERSTORMS ACROSS
THE REGION. ADDITIONAL SHOWERS OR THUNDERSTORMS MAY DEVELOP INTO
SATURDAY NIGHT AS ADDITIONAL ENERGY SLIDES ACROSS THE MID ATLANTIC.

THE MAIN STORM SYSTEM OVER THE GREAT LAKES WILL BEGIN TO SLIDE
ACROSS THE REGION SUNDAY INTO SUNDAY NIGHT. SEVERAL WAVES OF ENERGY
WILL PIVOT AROUND THE MAIN STORM...BRINGING INCREASED CHANCES OF
SHOWERS AND THUNDERSTORMS. A COUPLE OF THUNDERSTORMS COULD BRING
HEAVY RAIN AND GUSTY WINDS.

AS THE MAIN 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.

TUESDAY WILL BE DRIER AND COOLER WITH HIGH PRESSURE BUILDING IN FROM
THE WEST. THERE COULD BE A LINGERING SHOWER IN THE POTOMAC HIGHLANDS
TUESDAY.

&&

.AVIATION /19Z WEDNESDAY THROUGH MONDAY/...
A COLD FRONT WILL APPROACH THE REGION THIS AFTERNOON AND EVENING.
SCT SHRA AND SCT TSRA ARE POSSIBLE AT THE TERMINALS. SOME STRONGER
STORMS THIS EVENING MAY PRODUCE GUSTY WINDS. MVFR/IFR CONDITIONS
POSSIBLE WITHIN THUNDERSTORMS. VFR CONDITIONS EXPECTED OUTSIDE
ACTIVITY. THE COLD FRONT WILL CROSS OVERNIGHT BUT SHRA AND VCTS
ARE POSSIBLE INTO THURSDAY.

VFR CONDITIONS FRIDAY NIGHT AND SATURDAY WITH LIGHT AND VARIABLE
WINDS BECOMING SOUTHERLY.

MVFR OR IFR CONDITIONS COULD DEVELOP WITH SHOWER AND THUNDERSTORM
ACTIVITY SATURDAY NIGHT...MAINLY NEAR CHO AND MRB TERMINALS.

IFR CONDITIONS MAY BE MORE LIKELY AT ANY OF THE TERMINALS SUNDAY
WITH SHOWERS AND GUSTY THUNDERSTORMS.



&&

.MARINE...
SOUTHERLY FLOW WILL CONTINUE ACROSS THE WATERS THIS AFTERNOON AND
EVENING. SHOWERS AND THUNDERSTORMS ARE POSSIBLE THIS EVENING.
SOME STORMS MAY PRODUCE GUSTY WINDS LATE TONIGHT AND SMW`S ARE
POSSIBLE. A COLD FRONT WILL CROSS THE REGION OVERNIGHT AND INTO
THURSDAY MORNING. SHOWERS AND ISO THUNDERSTORMS WILL LINGER INTO
THURSDAY. HIGH PRESSURE WILL MOVE INTO THE REGION THURSDAY NIGHT
AND A SCA IS POSSIBLE LATE THURSDAY AND FRIDAY MORNING AS NRLY
WINDS INCREASE ACROSS THE WATERS.

SMALL CRAFT ADVISORIES MAY BE NEEDED SATURDAY NIGHT AND SUNDAY WITH
GUSTY SOUTH TO SOUTHWEST WINDS AHEAD OF A COLD FRONT.

&&

.TIDES/COASTAL FLOODING...
A SOUTHERLY FLOW HAS CAUSED TIDAL ANOMALIES TO BE AROUND ONE-HALF
TO THREE QUARTERS OF A FOOT ABOVE NORMAL. THE POSITIVE ANOMALIES
WILL CONTINUE THIS AFTERNOON AND EVENING...BUT THE NEXT HIGH TIDE
WILL BE THE LOWER OF THE TWO SO MINOR FLOODING IS NOT EXPECTED.
THE FLOW WILL TURN OFFSHORE BEHIND A SURFACE TROUGH LATE TONIGHT
INTO THURSDAY...SO ANOMALIES ARE EXPECTED TO DECREASE DURING THIS
TIME.

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...NONE.
VA...NONE.
WV...NONE.
MARINE...NONE.

&&

$$
SYNOPSIS...HAS
NEAR TERM...HAS
SHORT TERM...HAS
LONG TERM...KLW
AVIATION...HAS/KLW
MARINE...HAS/KLW
TIDES/COASTAL FLOODING...HAS






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