Area Forecast Discussion
Issued by NWS Sterling, VA

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FXUS61 KLWX 221441
AFDLWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
1041 AM EDT MON SEP 22 2014

.SYNOPSIS...
CONTINENTAL HIGH PRESSURE WILL BUILD OVER THE AREA INTO TONIGHT
AND PERSIST OVER NEW ENGLAND THROUGH MIDWEEK. A CUT OFF UPPER
LEVEL LOW PRESSURE SYSTEM WILL SETTLE NEAR THE SOUTHERN ATLANTIC
COAST INTO MID- WEEK...POSSIBLY DRIFTING UP THE COAST AND INTO OUR
AREA WEDNESDAY NIGHT INTO FRIDAY.

&&

.NEAR TERM /THROUGH TONIGHT/...
AS OF 14Z...NWLY GUSTS HAVE RESUMED WITH PEAK WINDS AROUND 30
MPH. THESE WILL SLOWLY EASE THROUGH THE AFTERNOON WITH GUSTS
ENDING BY SUNSET. UPSLOPE FLOW WILL CONTINUE TO BRING SPRINKLES TO
THE ALLEGHENIES WITH DOWNSLOPING FLOW SCATTERING OUT THE THE
CEILING EAST OF THERE.

COLD AIR ADVECTION WILL LIMIT FURTHER WARMING TODAY TO ONLY A FEW
DEGREES MORE...LOW TO MID 70S MAX TEMPS EXPECTED.

HIGH PRESSURE CROSSES PITTSBURGH TONIGHT. CALM AND CLEAR
CONDITIONS IN THE ALLEGHENIES SHOULD ALLOW TEMPERATURES TO DROP
INTO THE 30S IN VALLEYS WEST OF THE SHENANDOAH VALLEY. WILL DECIDE
IF A FROST ADVISORY IS NEEDED FOR THE 130PM UPDATE. MIN TEMPS
CHILLY ELSEWHERE...LOW TO MID 40S SHENANDOAH VALLEY AND MD/VA
PIEDMONT...UPR 40S INLAND COASTAL PLAINS...AND LOW TO MID 50S
URBAN/NEAR SHORE. MID 50S AT DCA WOULD MAKE FOR THE COOLEST NIGHT
SINCE MAY 19 WHEN IT HIT 49F.

&&

.SHORT TERM /TUESDAY THROUGH TUESDAY NIGHT/...
TUESDAY...CONDITIONS WILL BE EVEN MORE PLEASANT AS WINDS DROP OFF
WHILE HIGH PRESSURE SETTLES IN. CLEAR SKIES AND TEMPS BARELY ABOVE
70F W/ A LIGHT NLY BREEZE...WHILE THE JET STREAM RETREATS BRIEFLY
TO THE NORTH AND A CUT-OFF UPPER LOW HANGS OUT OFF THE CAROLINA
COAST.

&&

.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
HIGH PRESSURE WILL BE CENTERED OVER NORTHERN NEW ENGLAND AND WILL
KEEP THE MIDDLE ATLANTIC IN A WEDGE OF COOLER AIR WITH ONSHORE FLOW
WEDNESDAY INTO THURSDAY. AS THE HIGH WEAKENS AND BECOMES MORE
ELONGATED...THERE IS SOME POTENTIAL FOR AN UPPER LEVEL CUTOFF
LOW/TROUGH TO SWING OFF THE SOUTHEAST U.S COAST AND AID IN THE
DEVELOPMENT OF A WEAK SURFACE LOW OFF THE CAROLINAS THURSDAY INTO
FRIDAY. THERE IS MUCH UNCERTAINTY BETWEEN THE GFS WHICH KEEPS THE
HIGH A BIT STRONGER AND SUPPRESSES MOISTURE TO THE SOUTH AND THE
ECMWF WHICH IS WEAKER WITH THE HIGH AND FURTHER NORTH WITH THE
MOISTURE. THE NORTHWARD EXTENT OF THE RAINFALL WILL BE DEPENDENT ON
HOW STRONG THE HIGH IS AND ITS PLACEMENT. ATTM...CONTINUED TO SIDE
TOWARD THE GFS AND KEPT CHANCE POPS RELEGATED TO THE SOUTHERN
PORTION OF THE LWX CWFA. CLOUD COVER AND ONSHORE WIND COMPONENT WILL
KEEP HIGHS GENERALLY IN THE 70S WITH LOWS IN THE 40S AND 50S.

HIGH PRESSURE IS PROGGED TO RESTRENGTHEN FRIDAY THROUGH SUNDAY WITH
PLEASANT CONDITIONS EXPECTED ACROSS THE REGION. TEMPERATURES NEXT
WEEKEND MAY CLIMB BACK INTO THE UPPER 70S TO NEAR 80 DEGREES FOR THE
FIRST WEEKEND OF FALL.

&&

.AVIATION /15Z MONDAY THROUGH FRIDAY/...
NW WINDS OF 15-25KT THROUGH MIDDAY...EASING THROUGH THE AFTERNOON.
MOUNTAIN WAVE CLOUDS LESSEN THROUGH THE AFTERNOON TOO. GUSTS WILL
QUICKLY DROP OFF AFTER SUNSET TONIGHT. VFR CONDS AND LIGHT NLY
FLOW TONIGHT THROUGH TUE.

MAINLY VFR CONDITIONS EXPECTED WEDNESDAY INTO THURSDAY. THERE IS
SOME POTENTIAL FOR LOWER CEILINGS AND SOME LIGHT RAIN OR SHOWERS
THURSDAY INTO FRIDAY ESPECIALLY FROM KBWI TO KDCA TO KCHO AND POINTS
SOUTH. VFR CONDITIONS ARE EXPECTED OVER THE WEEKEND.

&&

.MARINE...
NWLY FLOW GUSTING 20 TO 25 KT THROUGH MIDDAY...EASING THROUGH THE
AFTERNOON. SCA FOR ALL WATERS UNTIL 6PM. LIGHT NLY FLOW TONIGHT
THROUGH TUESDAY WITH HIGH PRESSURE CENTERED TO THE NORTH.

A PERSISTENT ONSHORE FLOW WILL DEVELOP LATER WEDNESDAY AND PERSIST
INTO THURSDAY OR FRIDAY. SMALL CRAFT CONDITIONS MAY BE POSSIBLE FOR
A PORTION OF THE WATERS DURING THIS TIME FRAME. WINDS WILL REMAIN
BELOW SCA LEVELS AS HIGH PRESSURE BUILDS OVER THE MIDDLE ATLANTIC
NEXT WEEKEND.

&&

.TIDES/COASTAL FLOODING...
A PERSISTENT ONSHORE FLOW IS EXPECTED TO DEVELOP WEDNESDAY. THIS
WILL LEAD TO HIGHER THAN NORMAL WATER LEVELS PARTICULARLY OVER THE
WESTERN SHORE OF THE CHESAPEAKE BAY. MINOR TIDAL INUNDATION IS
POSSIBLE DURING HIGH TIDE STARTING WEDNESDAY NIGHT.

&&

.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...BAJ/GMS
NEAR TERM...BAJ/GMS
SHORT TERM...GMS
LONG TERM...KRW
AVIATION...BAJ/GMS/KRW
MARINE...BAJ/GMS/KRW
TIDES/COASTAL FLOODING...LWX







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