Area Forecast Discussion
Issued by NWS Sterling, VA

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FXUS61 KLWX 171819
AFDLWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
219 PM EDT WED SEP 17 2014

.SYNOPSIS...
HIGH PRESSURE WILL BUILD TOWARD THE EAST COAST THROUGH TONIGHT. A
WEAK COLD FRONT WILL PASS THROUGH THE AREA THURSDAY AND HIGH
PRESSURE WILL RETURN FOR FRIDAY AND SATURDAY. ANOTHER COLD FRONT
WILL PASS THROUGH THE AREA SUNDAY NIGHT INTO MONDAY.

&&

.NEAR TERM /THROUGH THURSDAY/...
HIGH PRESSURE WILL CONTINUE TO BRING DRY AND SEASONABLE CONDITIONS
TO THE AREA LATE THIS AFTERNOON. THE HIGH WILL SLOWLY BUILD EAST
TOWARD THE COAST TONIGHT WHILE A WEAK COLD FRONT APPROACHES FROM
THE OHIO VALLEY AND WESTERN PENNSYLVANIA. A LIGHT SOUTHERLY FLOW
AND SOME MORE CLOUD COVER WILL ALLOW MILDER CONDITIONS COMPARED TO
TUESDAY NIGHT. MIN TEMPS WILL RANGE FROM THE MID TO UPPER 40S
ALONG THE ALLEGHENY HIGHLANDS TO NEAR 60 IN WASHINGTON AND
BALTIMORE.

A WEAK COLD FRONT WILL PASS THROUGH THE REGION THURSDAY. THERE
WILL BE SOME INSTABILITY DUE TO A SOUTHERLY FLOW AHEAD OF THE
BOUNDARY...BUT FORCING AND MOISTURE WILL BE LIMITED. A COUPLE
SHOWERS ARE POSSIBLE...BUT PRECIPITATION AMOUNTS WILL BE LIGHT AND
MOST AREAS WILL END UP DRY. MAX TEMPS WILL RANGE FROM THE 60S IN
THE MOUNTAINS TO THE MIDDLE 70S NEAR WASHINGTON AND BALTIMORE.

&&

.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY/...
THE COLD FRONT WILL DROP TO OUR SOUTH THURSDAY NIGHT BEFORE
STALLING OUT OVER THE SOUTHEASTERN CONUS FRIDAY THROUGH SATURDAY.
HIGH PRESSURE WILL BUILD INTO NEW ENGLAND THURSDAY NIGHT THROUGH
FRIDAY BEFORE MOVING OFF THE COAST SATURDAY. THE SURFACE RIDGE
AXIS WILL REMAIN OVER THE REGION DURING THIS TIME.

THE RIDGE AXIS SHOULD REMAIN CLOSE ENOUGH TO BRING DRY CONDITIONS
TO THE AREA DURING THIS TIME BUT CLOUDS MAY HANG AROUND DUE TO AN
ONSHORE COMPONENT TO THE LOW-LEVEL FLOW...ESPECIALLY ACROSS THE
SHENANDOAH VALLEY INTO THE POTOMAC HIGHLANDS. AN EAST TO NORTHEAST
FLOW FRIDAY WILL CAUSE MAX TEMPS TO BE BELOW CLIMO...BUT WINDS
SHOULD TURN TOWARD THE SOUTHEAST SATURDAY ALLOWING FOR WARMER
CONDITIONS.

&&

.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
HIGH PRESSURE WILL REMAIN WEDGED SOUTHWARD BETWEEN THE APPALACHIAN
MOUNTAINS AND EAST COAST SATURDAY NIGHT...KEEPING DRY CONDITIONS IN
THE REGION.

A COLD FRONT WILL MOVE FROM THE EASTERN GREAT LAKES TO THE EAST
COAST SUNDAY AND SUNDAY NIGHT. THERE IS A CHANCE FOR SHOWERS ALONG
THE FRONT WEST OF THE BLUE RIDGE SUNDAY AND IN ALL AREAS SUNDAY
NIGHT. UPPER LEVEL SUPPORT SHOULD PIVOT NORTHEAST INTO EASTERN
CANADA BY SUNDAY NIGHT...THE FRONT COULD STALL ACROSS THE DELMARVA
PENINSULA AND TIDEWATER OF VIRGINIA BRIEFLY.

A REINFORCING PUSH OF UPPER LEVEL ENERGY MONDAY SHOULD PUSH THE
FRONT OFFSHORE BY LATE MONDAY. HIGH PRESSURE WILL GRADUALLY BUILD
INTO THE REGION MONDAY NIGHT THROUGH WEDNESDAY TO ALLOW FOR THE NEXT
PUSH OF COLDER AIR.

&&

.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
A WEAK COLD FRONT WILL APPROACH THE TERMINALS TONIGHT BEFORE
PASSING THROUGH THURSDAY. VFR CONDITIONS AND LIGHT WINDS ARE
EXPECTED MOST OF THE TIME...BUT PATCHY BR IS POSSIBLE LATE TONIGHT
INTO EARLY THURSDAY AND A STRAY SHOWER CANNOT BE RULED OUT
THURSDAY AFTERNOON.

HIGH PRESSURE WILL RETURN FOR FRIDAY AND SATURDAY...BRINGING MORE
VFR CONDITIONS. VFR CONDITIONS SATURDAY NIGHT THROUGH SUNDAY WITH
LIGHT AND VARIABLE WINDS.

&&

.MARINE...
HIGH PRESSURE WILL SLOWLY BUILD TOWARD THE COAST TONIGHT AND A
WEAK COLD FRONT WILL PASS THROUGH THE WATERS THURSDAY. AN ISOLATED
SHOWER IS POSSIBLE THURSDAY AFTERNOON. HIGH PRESSURE WILL BUILD
TOWARD THE WATERS THURSDAY NIGHT AND FRIDAY. A PRESSURE SURGE WILL
CAUSE NORTH-NORTHEAST WINDS TO INCREASE. A SMALL CRAFT ADVISORY IS
IN EFFECT FOR THE MARYLAND CHESAPEAKE BAY AND LOWER TIDAL POTOMAC
RIVER LATE THURSDAY NIGHT THROUGH FRIDAY MORNING.

THE FLOW WILL TURN TOWARD THE SOUTHEAST LATER FRIDAY THROUGH
SATURDAY. WINDS MAY BE CLOSE TO SCA CRITERIA AT TIMES...BUT GUSTS
HAVE BEEN CAPPED AT 15 KNOTS FOR NOW SINCE THE GRADIENT IS
EXPECTED TO WEAKEN A BIT.

NO MARINE HAZARDS SATURDAY NIGHT. SMALL CRAFT ADVISORIES ARE
POSSIBLE SUNDAY WITH AN AREA OF LOW PRESSURE NEAR THE TIDEWATER OF
VIRGINIA AND THE MAIN STEM CHESAPEAKE BAY.

&&

.TIDES/COASTAL FLOODING...
HIGH PRESSURE WILL CONTINUE TO BUILD TOWARD THE COAST TONIGHT. THE
FLOW WILL TURN TOWARD THE SOUTHEAST DURING THIS TIME...CAUSING
TIDAL ANOMALIES TO INCREASE. TIDAL ANOMALIES UP TO A FOOT ABOVE
NORMAL ARE EXPECTED TONIGHT AND THIS WILL CAUSE MINOR TIDAL
FLOODING FOR SENSITIVE AREAS NEAR HIGH TIDE. A COASTAL FLOOD
ADVISORY IS IN EFFECT TONIGHT FOR THE MARYLAND CHESAPEAKE BAY
FROM ANNE ARUNDEL COUNTY THROUGH ST MARYS COUNTY.
ELSEWHERE...MINOR FLOODING IS POSSIBLE WITH THE HIGH TIDE CYCLE
LATE TONIGHT INTO EARLY THURSDAY BUT A COASTAL FLOOD ADVISORY HAS
NOT BEEN ISSUED AT THIS TIME DUE TO SLIGHTLY HIGHER THRESHOLDS.

A WEAK COLD FRONT WILL PASS THROUGH THE WATERS THURSDAY AND HIGH
PRESSURE WILL BUILD OVER NEW ENGLAND BEHIND THIS FRONT. AN
EASTERLY COMPONENT TO THE WIND IS EXPECTED TO CONTINUE DURING THIS
TIME AND IT WILL LIKELY LAST THROUGH THE WEEKEND.
THEREFORE...MINOR TIDAL FLOODING IS POSSIBLE NEAR TIMES OF HIGH
TIDE THROUGH THE WEEKEND. THE BEST CHANCE FOR MINOR TIDAL FLOODING
WILL BE DURING THE LATE EVENING AND MORNING HIGH TIDE CYCLE WHICH
IS THE HIGHER OF THE TWO.

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...COASTAL FLOOD ADVISORY FROM 9 PM THIS EVENING TO 4 AM EDT
     THURSDAY FOR MDZ014-017-018.
VA...NONE.
WV...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 2 AM TO NOON EDT FRIDAY FOR
     ANZ530>534-537-539>541-543.

&&

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






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