Area Forecast Discussion
Issued by NWS Sterling, VA

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000
FXUS61 KLWX 010759
AFDLWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
359 AM EDT MON SEP 1 2014

.SYNOPSIS...
BERMUDA HIGH PRESSURE WILL PERSIST THROUGH TUESDAY. A BOUNDARY WILL
PERSIST OVER THE AREA TODAY. A WEAK COLD FRONT WILL CROSS THE
AREA TUESDAY NIGHT...FOLLOWED BY HIGH PRESSURE INTO THE WEEKEND.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
A REMNANT BOUNDARY FROM EVENING ACTIVITY IS STILL LYING EAST-WEST
ACROSS THE AREA THIS MORNING. THIS DIFFUSE BOUNDARY IS CONVERGENCE
BETWEEN THE BERMUDA HIGH AND LOW PRESSURE OVER THE WRN GREAT LAKES
AND WILL PERSIST OVER THE AREA INTO TONIGHT. ISOLATED SHOWERS AND
THUNDERSTORMS WILL CONTINUE INTO THE DAY. A DIURNAL RESURGENCE ALONG
THIS BOUNDARY WILL BRING SCATTERED THUNDERSTORMS THIS AFTERNOON AND
EVENING. PWATS AROUND 2 INCHES WILL LEAD TO MORE LOCALLY HEAVY
RAINFALL AND THE POTENTIAL FOR ISOLATED FLASH FLOODING.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM TUESDAY/...
WEAK SFC RIDGING CROSSES THE CENTRAL MID-ATLANTIC TONIGHT INTO
TUESDAY...MAKING FOR AN OVERNIGHT/MOST OF TUESDAY REPRIEVE FROM
THUNDERSTORMS. WITH THE BERMUDA HIGH IN PLACE...EXPECT TUESDAY TO
HAVE THE HIGHEST TEMPERATURE DAY SINCE JULY. MAX TEMPS LOW TO MID
90S ACROSS LOWER ELEVATIONS. TEMPERATURES MAY BE LOWER OUT WEST
WHERE ACTIVITY WILL FIRE FIRST AHEAD OF AN APPROACHING WEAK COLD
FRONT.

&&

.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
BEHIND A SHARP AND POTENT UPPER TROUGH AXIS WILL BE LARGE ZONAL FLOW
PATTERN ABOVE THE NRN HALF OF THE CONUS DURING THE MIDDLE OF THE
CURRENT WEEK. THIS UPPER-LEVEL HIGHWAY OF FAST-MOVING FLOW WILL NOT
ONLY TAKE THE TUE TROUGH PASSAGE QUICKLY AWAY FROM THE AREA AND OFF
TOWARD NEW ENGLAND...BUT BRING ANOTHER TOWARD THE AREA JUST A COUPLE
OF DAYS LATER - ALL THE WAY FROM THE NRN ROCKIES. THE UPPER RIDGE
LAID OUT ACROSS THE SRN HALF OF THE CONUS HOWEVER...WILL KEEP THESE
LOW PRES SYSTEM PASSES FROM MAKING A RUN TOO FAR SOUTH. THE FRONTAL
PASSAGE OF THE TUE/EARLY WED SYSTEM AND THE LATE WEEK ONE WILL
LARGELY SKIM THE REGION W/ THE JUST THE RESIDUAL/LEFTOVER EFFECTS OF
THE MORE POTENT SYSTEM FURTHER TO THE NORTH.

EVEN W/ THE COLD FRONT EXPECTED TO MOVE ACROSS THE AREA LATE TUE W/
MORE SHOWER/TSTM ACTIVITY...THE UPPER DYNAMICS BEHIND THE STRENGTH
OF THE FRONT WILL TAKE OFF TO THE NE. THE LEFTOVER BOUNDARY WILL
STALL-OUT TO OUR SOUTH AND ALLOW FOR WEAK HIGH PRES TO BUILD IN
ACROSS THE MID-ATLC STATES WED INTO THU. ONLY A SLIGHT AIRMASS
CHANGE BEHIND THE FRONT WILL PREVENT TEMPS FROM REACHING THE HIGHER
LEVELS EXPECTED ON TUE - THAT OF L-M90S. INSTEAD...MUCH OF THE AREA
WILL TOP OUT IN THE M80S...W/ U80S DOTTING THE I-95 CORRIDOR AREA
AND EAST. SKIES WILL CLEAR OUT AND A LIGHT WNW WIND WILL DOWNSLOPE
AND HELP BUMP UP TEMPS A COUPLE MORE DEG.

WITH THE STALLED BOUNDARY TO OUR SOUTH TO CLOSE OUT THE WEEK...DAILY
DIURNAL SHOWERS/TSTMS WILL BE DEVELOPING ALONG IT - ACROSS THE
CAROLINAS AND POSSIBLY UP INTO CNTRL VA...BUT LIKELY JUST SHY OF THE
SRN PERIPHERY OF THE CWA. THE NEXT UPPER LEVEL DISTURBANCE WILL BE
THE FAST-MOVING SYSTEM COMING OUT OF THE NRN PLAINS AND OVER THE
GREAT LAKES REGION TO CLOSE OUT THE WEEK. THE SFC HIGH WILL ROLL OFF
THE COAST AND START UP AN ONSHORE FLOW AS THE COLD FRONT APPROACHES.
THIS WILL HELP TO START OUR COOL-DOWN FROM THE ABNORMALLY HOT/HUMID
CONDITIONS OF THE PAST FEW DAYS. PRECIP CHANCES WILL INCREASE W/ THE
FRONTAL PASSAGE ON FRI INTO SAT.

&&

.AVIATION /08Z MONDAY THROUGH FRIDAY/...
ACTIVE PATTERN CONTINUES TODAY AS SCATTERED HEAVY THUNDERSTORMS FORM
ALONG A BOUNDARY THAT IS LYING WEST TO EAST ACROSS THE AREA THIS
MORNING. EXPECT IFR CONDS UNDER THUNDERSTORMS. LIGHT SOUTHWEST OR
WEST FLOW TODAY AND TUESDAY. COLD FRONT APPROACHES TUESDAY WITH
LEADING THUNDERSTORM ENTERING FROM THE WEST LATE IN THE DAY.

THE HOT/HUMID AIRMASS WILL BEGIN TO WANE TOWARD THE MIDDLE OF THE
WEEK. SKIES WILL CLEAR OUT ON WED...W/ WINDS SHIFTING TOWARD NWLY
AND HIGH PRES BUILDING IN FROM THE NORTH. THE HIGH WILL KEEP
CONDITIONS QUIET INTO FRI...AS A COLD FRONT APPROACHES FROM THE
UPPER MIDWEST. THE FRONT IS EXPECTED TO BRING MORE PRECIP FROM FRI
INTO SAT...SAGGING JUST S OF THE AREA FOR THE COMING WEEKEND.

&&

.MARINE...
10 TO 15KT SWLY/WLY FLOW THROUGH TUESDAY. ISOLATED THUNDERSTORMS
THIS MORNING...THEN SCATTERED THUNDERSTORMS LATE THIS AFTERNOON
AND EVENING OVER THE WATERS.

HIGH PRESSURE WILL BUILD BEHIND A COLD FRONT LATE TUE EVE. THE FRONT
WILL DRIFT JUST SOUTH OF THE AREA...TOWARD THE CAROLINAS. THE SFC
HIGH WILL LARGELY KEEP WINDS LIGHT INTO THE LATTER HALF OF THE
WEEK...MOVING OFF THE COAST BY EARLY FRI - AHEAD OF ANOTHER COLD
FRONT. SCA CONDITIONS NOT ANTICIPATED FOR THE MED/LONG RANGES OF THE
FORECAST.

&&

.TIDES/COASTAL FLOODING...
TIDAL DEPARTURES WILL CONTINUE TO DECREASE ACROSS THE WATERS
THROUGH THE MORNING AS SWLY FLOW UP TO 15 KT PERSISTS. WATER
LEVELS ARE EXPECTED TO RETURN TO NORMAL BY MIDDAY.

&&

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

&&

$$
SYNOPSIS...BAJ
NEAR TERM...BAJ
SHORT TERM...BAJ
LONG TERM...GMS
AVIATION...BAJ/GMS
MARINE...BAJ/GMS
TIDES/COASTAL FLOODING...BAJ






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