-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KLWX 211851
AFDLWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
251 PM EDT MON JUL 21 2014

.SYNOPSIS...
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HIGH PRESSURE WILL REMAIN ALONG THE EASTERN SEABOARD THROUGH
TUESDAY. TEMPERATURES WILL SLOWLY RISE THROUGH WEDNESDAY AHEAD OF
A COLD FRONT EXPECTED TO MOVE INTO THE AREA THURSDAY. HIGH
PRESSURE IS EXPECTED TO RETURN TO THE MID ATLANTIC STATES TO END
THE WORKWEEK.
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&&

.NEAR TERM /THROUGH TONIGHT/...
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HIGH PRESSURE CONTINUES TO BE LOCATED FROM THE NEW ENGLAND COAST
DOWN THROUGH THE MID-ATLANTIC...KEEPING A SOUTHEAST LOW
LEVEL FLOW ACROSS THE CWA. SOME SHOWERS HAVE BEEN NOTED ACROSS THE
POTOMAC HIGHLANDS AND ACROSS THE VIRGINIA FOOTHILLS. EXPECT MORE
DEVELOPMENT THROUGH THE REST OF THE AFTERNOON...PARTICULARLY FROM
THE FOOTHILLS AND NEAR THE BLUE RIDGE ON WEST. CAN/T RULE OUT
ISOLATED THUNDER EITHER BUT WITH SO MUCH CLOUD COVER INSTABILITY
IS WEAK AND THESE WILL BE FEW AND FAR BETWEEN.

SHOWERS SHOULD FAVOR A DIURNAL TREND...THUS EXPECT
DIMINISHING/LITTLE ACTIVITY AFTER DARK. CLOUDS WILL STICK
AROUND...POSSIBLY MORPHING INTO A STRATUS DECK LATE TONIGHT.

FAVORED BLEND OF BIAS CORRECTED SREFS/ADJMAV FOR MINIMA.
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&&

.SHORT TERM /TUESDAY THROUGH WEDNESDAY/...
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FLAT RIDGE BUILDS IN FOR TUESDAY. DAY LIKELY STARTS OUT WITH
PLENTY OF CLOUDS BUT SOME PEEKS OF SUNSHINE SHOULD OCCUR IN THE
AFTERNOON. RIDGE MAY HELP LIMIT CONVECTION...BUT WITH BETTER
MOISTURE/INSTABILITY THAN RECENT DAYS CAN/T RULE OUT A FEW
SHOWERS/THUNDERSTORMS DURING THE AFTERNOON/EVENING MAINLY NEAR THE
HIGHER TERRAIN.

HEIGHTS START TO DECREASE FOR WEDNESDAY. DESPITE THIS...A SHIFT TO
A SOUTHWEST WIND AND SOME SUNSHINE SHOULD SUPPORT WARMER
TEMPERATURES LIKELY AOA 90 DEG EAST OF THE BLUE RIDGE. MODELS ALSO
HINT AT THE PRESENCE OF A PRE-FRONTAL TROUGH...THUS EXPECT A
CHANCE OF SHOWERS AND THUNDERSTORMS ACROSS THE CWA BY AFTERNOON.
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&&

.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
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HEAVY SHOWERS AND STRONG TO POSSIBLY SEVERE THUNDERSTORMS MAY
DEVELOP DURING THE DAY THURSDAY DUE TO A COMBINATION OF UPPER
ENERGY...A COLD FRONT AND DAYTIME HEATING. THE STRONGEST
THUNDERSTORMS COULD PRODUCE DAMAGING WINDS AND LOCALLY HEAVY RAIN.
HIGH CAPE AND LOW TO MODERATE SHEAR COULD LEAD TO THE DAMAGING
WINDS...WHILE PRECIPITABLE WATER VALUES OF AROUND 2 INCHES COULD
INDICATE HEAVY RAIN WOULD BE A THREAT FROM THE STORMS. AS OF
NOW...TIMING OF THE HEAVIEST ACTIVITY APPEARS TO BE THURSDAY
AFTERNOON AND EVENING.

A SURFACE COLD FRONT WILL PUSH THROUGH OUR REGION THURSDAY NIGHT TO
ALLOW FOR A RIDGE OF HIGH PRESSURE TO BUILD IN FROM THE NORTHWEST.
THIS FRONT HAS THE POTENTIAL TO STALL NEAR THE VIRGINIA AND NORTH
CAROLINA BORDER THURSDAY NIGHT INTO FRIDAY...THUS MAYBE KEEPING A
SLIGHT CHANCE OF RAIN SHOWERS ACROSS THE SOUTHERN TWO-THIRDS OF THE
CWA WITH A SLIGHT CHANCE OF THUNDERSTORMS ACROSS THE VIRGINIA
PIEDMONT AND MAIN STEM CHESAPEAKE BAY.

HIGH PRESSURE SHOULD GRADUALLY PUSH THE FRONT FARTHER SOUTH TO ALLOW
COOLER AND DRIER AIR TO MOVE IN ACROSS THE CWA FRIDAY AFTERNOON
THROUGH MIDDAY SATURDAY. THE HIGH IS EXPECTED TO MOVE OFFSHORE
SATURDAY AFTERNOON AND SATURDAY NIGHT. AN ONSHORE FLOW DEVELOP
DURING THE PERIOD...AIDING IN AN INCREASE IN LOW LEVEL MOISTURE.
GIVEN THE UNCERTAINTY OF THE POSITION OF THE HIGH...NEAR LONG ISLAND
OR THE TIDEWATER OF VIRGINIA...WE LEFT A CHANCE OF RAIN SHOWERS
SATURDAY AND A SLIGHT CHANCE OF A SHOWER OR THUNDERSTORM SATURDAY
NIGHT. DESPITE THE HIGH BEING THE FAVORITE...BOTH THE EURO AND GFS
INDICATE A FEW RIPPLES IN THE UPPER LEVEL FLOW THAT MAY INDICATE A
WEAK DISTURBANCE OR TWO MAY FIND ITS WAY ACROSS OUR CWA...HENCE
THE CHANCE OF A SHOWER OR STORM.

SUNDAY AND MONDAY WILL BE A PRECURSOR OF AN ACTIVE MIDWEEK OF
SHOWERS AND THUNDERSTORMS AS A STRONGER UPPER LEVEL STORM SYSTEM
PIVOTS ACROSS THE GREAT LAKES.
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&&

.AVIATION /18Z MONDAY THROUGH SATURDAY/...
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VFR PREVAILS AT THE TERMINALS THIS AFTERNOON...HOWEVER PERIODIC
MVFR CIGS STILL POSSIBLE AT MRB/CHO THROUGH AFTERNOON AND COULD
EVEN LINGER INTO THE EVENING. GIVEN SOUTHEAST FLOW...ALSO EXPECT
STRATUS TO DEVELOP TOWARD THE HUBS TONIGHT...AND HAVE INCLUDED
MVFR TO IFR CIGS IN TAFS LATE TONIGHT INTO EARLY TUESDAY MORNING.
FOLLOWED TRENDS OF SREFS/LAMP/MAV IN A RETURN TO VFR BY TUESDAY
AFTERNOON ALTHOUGH THERE WILL BE SCATTERED SHOWERS.

AFTERNOON/EVENING THUNDERSTORMS ARE POSSIBLE ON WEDNESDAY. IFR OR
LIFR CONDITIONS ARE POSSIBLE AT ANY OF THE TERMINALS THURSDAY AS
LOCALLY HEAVY RAINFALL AND GUSTY WINDS ACCOMPANY THE SHOWERS AND
THUNDERSTORMS.
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&&

.MARINE...
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HIGH PRESSURE ALONG THE COAST KEEPS A SOUTHEAST FLOW IN PLACE
THIS AFTERNOON...ALTHOUGH WEAK GRADIENT SHOULD KEEP SPEEDS 10 KT
OR LESS. WINDS TURN MORE TO THE SOUTH TONIGHT INTO
TUESDAY...CHANNELLING LIKELY TO PROMOTE WINDS INCREASING CLOSER TO
15 KT UP THE MAIN CHANNEL OF THE BAY. CHANNELLING COULD RESULT IN
MARGINAL SCA CONDITIONS UP THE BAY BY WEDNESDAY EVENING.

NO MARINE HAZARDS EXPECTED THURSDAY THROUGH FRIDAY...EXCEPT FOR
POSSIBLE GUSTY WINDS IN THUNDERSTORMS THURSDAY.
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&&

.TIDES/COASTAL FLOODING...
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ANOMALIES CONTINUE TO BE AROUND 1 FT ABOVE NORMAL ON THE WESTERN
SHORE OF THE CHESAPEAKE BAY THIS AFTERNOON. THESE MAY EVEN MOVE
UPWARD A LITTLE THROUGH TONIGHT GIVEN SOUTHEAST FLOW. GIVEN
CURRENT ANOMALIES...THIS WILL PUT WATER LEVELS ABOVE MINOR FLOOD
AT ANNAPOLIS AND RIGHT NEAR MINOR FLOOD AT BALTIMORE. CBOFS HAS
BOTH LOCATIONS ABOVE MINOR FLOOD DURING HIGH TIDE AS WELL AND WITH
DECENT CONFIDENCE WILL BE ISSUING A COASTAL FLOOD ADVISORY FOR
ANNE ARUNDEL AND SOUTHERN BALTIMORE COUNTIES FOR TONIGHT/S HIGH
TIDE. WILL HAVE TO WATCH OTHER COUNTIES ON THE WESTERN SHORE OF
THE BAY IF ANOMALIES INCREASE FURTHER.

RISK OF MINOR TIDAL FLOODING MAY OCCUR AGAIN DURING HIGH TIDE
TUESDAY NIGHT WITH SOUTHERLY FLOW IN PLACE.
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&&

.LWX WATCHES/WARNINGS/ADVISORIES...
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DC...NONE.
MD...COASTAL FLOOD ADVISORY FROM 1 AM TO 6 AM EDT TUESDAY FOR
     MDZ011-014.
VA...NONE.
WV...NONE.
MARINE...NONE.
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&&

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