Area Forecast Discussion
Issued by NWS Sterling, VA

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FXUS61 KLWX 030202 AAA
AFDLWX

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
1002 PM EDT THU JUL 2 2015

.SYNOPSIS...
A STATIONARY FRONT WILL REMAIN OVER CENTRAL VIRGINIA AND SOUTHERN
MARYLAND THROUGH THE WEEKEND. SEVERAL WAVES OF LOW PRESSURE WILL
MOVE EAST ALONG THE FRONT AS AN ACTIVE PATTERN CONTINUES. HIGH
PRESSURE WILL RETURN FOR THE FIRST HALF OF NEXT WEEK.

&&

.NEAR TERM /THROUGH FRIDAY/...
A WEAK BOUNDARY REMAINS NEARLY STATIONARY OVER CENTRAL VIRGINIA
THIS EVENING. THERE IS A SMALL DEWPOINT GRADIENT ALONG THE
BOUNDARY...LOWER TO MIDDLE 60S NORTH OF THE BOUNDARY AND UPPER
60S/LOWER 70S SOUTH OF THE BOUNDARY. THIS BOUNDARY WILL REMAIN
NEARLY STATIONARY OVER CENTRAL VIRGINIA TONIGHT. AN UPPER-LEVEL
DISTURBANCE AND SURFACE LOW PRESSURE ALONG THE BOUNDARY WILL
CONTINUE TO MOVE OFF TO THE EAST THIS EVENING. SUBSIDENCE BEHIND
THIS WILL ALLOW FOR MOST AREAS TO TURN OUT DRY ALONG WITH BREAKS
IN THE CLOUD COVER.

ANOTHER WAVE OF LOW PRESSURE AND ITS ASSOCIATED UPPER-LEVEL
DISTURBANCE WILL TRACK THROUGH THE MIDWEST TONIGHT AND INTO THE
OHIO VALLEY BY DAYBREAK. AS THIS SYSTEM DRAWS CLOSER...MORE HIGH
AND MID-LEVEL CLOUDS WILL OVERSPREAD THE AREA AND OVERRUNNING WILL
ALSO INCREASE AS THE LOW-LEVEL FLOW BACKS TO THE
SOUTHEAST...ALLOWING FOR WARM AND MOIST AIR TO OVERRUN THE SURFACE
COOLER AIR IN PLACE. THIS WILL CAUSE PRECIPITATION TO
DEVELOP ACROSS CENTRAL VIRGINIA WELL AFTER MIDNIGHT WHERE
OVERRUNNING WILL BE DEEPEST. ELSEWHERE...CONDITIONS SHOULD REMAIN
DRY WITH INCREASING CLOUDS AND AREAS OF FOG. FOG MAY BE LOCALLY
DENSE DUE TO BREAKS IN THE CLOUD COVER THIS EVENING AND SATURATED
SOILS FROM RECENT RAINFALL.

THE WAVE OF LOW PRESSURE WILL TRACK EAST ALONG THE STALLED FRONT
ON FRIDAY...IN ADDITION TO POTENTIAL MID-LEVEL DISTURBANCES
ROTATING OUT OF A DEEPENING TROUGH OVER THE OHIO VALLEY. EXPECT
SHOWERS TO INCREASE IN COVERAGE FROM SW TO NE FROM MORNING INTO
THE AFTERNOON. A LITTLE QUESTIONABLE HOW FAR NORTH THE ACTIVITY
GETS AND WHETHER IT WILL BE IN ONE SLUG OR THE OFF/ON VARIETY.
THEREFORE HAVE A GRADIENT OF POPS FROM 40 TO 80 NE TO W AND
SW...BUT THESE MAY NEED TO BE RAISED. WE WILL LIKELY BE ON THE
STABLE SIDE OF THE BOUNDARY...SO THUNDER SHOULD BE RATHER
LIMITED...ESPECIALLY WITH NORTHWARD EXTENT. THINK THAT THE RAIN
WILL FALL AT A SLOW ENOUGH RATE TO LIMIT A FLOOD THREAT...BUT WITH
A MOIST ATMOSPHERE AND WET SOILS...THIS WILL NEED TO BE MONITORED.
WENT ON COOL SIDE OF GUIDANCE FOR HIGHS WITH CLOUDS/PRECIP...WITH
MOST LOCATIONS IN THE 70S.

&&

.SHORT TERM /FRIDAY NIGHT THROUGH SATURDAY NIGHT/...
FRONTAL BOUNDARY WILL REMAIN JUST SOUTH OF THE REGION WITH WAVES
OF LOW PRESSURE RIDING NORTHWARD ALONG THE BOUNDARY. SHOWERS WILL
REMAIN IN THE FORECAST FRIDAY NIGHT AND INTO THE 4TH OF JULY
HOLIDAY. WINDS WILL LIKELY REMAIN OUT OF THE EAST OR NORTHEAST
WHICH WILL KEEP THE ATMOSPHERE COOLER AND MORE STABLE. HAVE
REMOVED MENTION OF THUNDERSTORMS FROM THE FORECAST ATTM. HIGH
TEMPERATURES WILL LIKELY ONLY REACH THE MIDDLE TO UPPER 70S
DURING SATURDAY WITH LOWS IN THE 60S.

&&

.LONG TERM /SUNDAY THROUGH THURSDAY/...
FRONTAL BOUNDARY SOUTH OF THE AREA DRIFTS FARTHER SOUTH SUNDAY
AND MONDAY AS UPR RIDGE BUILDS EAST OVER THE MIDWEST. ANY ISOLATED
TO POSSIBLY SCATTERED THUNDERSTORMS BOTH DAY LOOK TO BE DIURNALLY
DRIVEN. BY TUESDAY FRONT RETURNS TO AREA AND A COASTAL LOW DEVELOPS
OFF DELMARVA IN RESPONSE TO UPPER LEVEL TROUGH. INCREASING CHANCE
OF CONVECTIVE DEVELOPMENT ESPECIALLY OVER EASTERN MD AND VA
TIDEWATER. NEXT COLD FRONT APPROACHES REGION FROM THE MIDWEST
WEDNESDAY AND SLOWS WITH MORE ACTIVE WEATHER INTO LATE NEXT WEEK.

&&

.AVIATION /02Z FRIDAY THROUGH TUESDAY/...
MAINLY DRY CONDITIONS THIS EVENING. SHOWERS MAY OVERSPREAD KCHO
TOWARD DAYBREAK. SHOWERS WILL OVERSPREAD MOST OF THE TERMINALS
FRIDAY...BUT COVERAGE ACROSS KBWI AND KMTN IS STILL A BIT
UNCERTAIN AT THIS TIME. THERE IS A LIMITED CHANCE OF THUNDER
DURING THE AFTERNOON AND EVENING HOURS. IN ADDITION...FOG AND/OR
LOW CIGS MAY DEVELOP TONIGHT INTO FRIDAY MORNING. GENERALLY HAVE
MVFR/IFR CONDITIONS INDICATED. WINDS WILL REMAIN LIGHT
TONIGHT...TURNING TOWARD THE SOUTHEAST FRIDAY AFTERNOON.

OVERCAST CONDITIONS ALONG WITH A CHANCE FOR SHOWERS WILL PERSIST
SATURDAY AND PERHAPS INTO SUNDAY. CONDITIONS WILL LIKELY IMPROVE
LATER SUNDAY AND INTO EARLY NEXT WEEK.

&&

.MARINE...
FRONT STALLED SOUTH OF THE AREA THROUGH FRIDAY. SUB-SCA CONDITIONS
LIKELY. HOWEVER BY LATE FRIDAY AFTERNOON...LOW PRESSURE WILL TRACK
ALONG THE FRONT AND MAY INCREASE EASTERLY WINDS OVER THE SOUTHERN
PARTS OF THE WATERS. PERIODS OF SHOWERS WILL CROSS THE
WATERS...MAINLY FRIDAY AFTERNOON AND EVENING. THEIR MAIN IMPACT
WILL BE TO REDUCE VSBY...BUT EMBEDDED THUNDERSTORMS COULD ALSO
BRING GUSTIER WINDS. EXPECT THESE TO BE ISOLATED AND CONFINED
TOWARD THE SOUTHERN PARTS OF THE WATERS.

WINDS ARE EXPECTED TO REMAIN BELOW SCA LEVELS SATURDAY INTO
MONDAY. OCCASIONAL SHOWERS COULD IMPACT THE WATERS DURING THIS
TIME BUT THE THREAT FOR THUNDERSTORMS IS LOW.

&&

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

&&

$$
SYNOPSIS...KRW
NEAR TERM...BJL/ADS
SHORT TERM...KRW
LONG TERM...CEM
AVIATION...BJL/ADS/KRW
MARINE...BAJ/BJL/ADS/KRW


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