Area Forecast Discussion


024 
FXUS61 KLWX 211845
AFDLWX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
245 PM EDT TUE OCT 21 2014
.SYNOPSIS...
A COLD FRONT WILL MOVE THROUGH THE MID ATLANTIC REGION THIS
EVENING. LOW PRESSURE WILL PERSIST ALONG THE COAST THROUGH THURSDAY.
HIGH PRESSURE WILL RETURN FOR THE END OF THE WORKWEEK AND INTO THE
WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
DEVELOPING SURFACE LOW PRESSURE WILL MOVE THROUGH THE REGION LATE
THIS AFTERNOON AND EVENING...THEN OFFSHORE OVERNIGHT. BROAD CLOSED
UPPER LOW OVER THE LOWER GREAT LAKES WILL ALSO DROP INTO THE MID-
ATLANTIC REGION BY THIS EVENING...AND BECOME BETTER ORGANIZED AS
IT MOVES INTO THE TIDEWATER REGION OVERNIGHT. 
COMBINATION OF COOL AIR ALOFT...AN APPROACHING COLD FRONT AND
MARGINAL SURFACE INSTABILITY IS PRODUCING SCATTERED RAIN AND
SHOWERS OVER THE SHENANDOAH VALLEY...POTOMAC HIGHLANDS AND
UPSTREAM ACROSS WV/PA AND OHIO LATE THIS AFTERNOON. WITH AROUND
500 J/KG OF SBCAPE...WILL HAVE ENOUGH INSTABILITY FOR SOME
ISOLATED HEAVIER SHOWERS AND PERHAPS A FEW THUNDERSTORMS LATE THIS
AFTERNOON AND EVENING. AFTERNOON HIGH TEMPS ARE PRIMARILY IN THE
60S...WITH A FEW 70S NOTED IN THE VA PIEDMONT. COOLER TEMPS OVER
THE MOUNTAINS WHERE CLOUD COVER AND RAIN IS KEEPING TEMPS IN THE
UPPER 50S.
RAIN WILL CONTINUE OVERNIGHT AS THE SURFACE AND UPPER LOWS MOVE
JUST TO THE EAST AND SOUTHEAST OF THE FORECAST AREA. BASIN WIDE
RAIN AMOUNTS WILL LIKELY BE A QUARTER OF AN INCH OR LESS
OVERNIGHT...BUT SOME LOCAL AREAS MAY SEE HIGHER AMOUNTS WITH
LOCALIZED PERIODS OF MORE MODERATE RAINFALL. STEADY BREEZE AROUND
5-10KT FROM THE NW CONTINUES AS THE PRESSURE GRADIENT AROUND THE
BACK SIDE OF THE SURFACE LOW INCREASES. LOWS TONIGHT RANGE FROM
THE LOW 40S IN THE HIGHLANDS TO THE LOW 50S ALONG AND EAST OF
I-95.
&&
.SHORT TERM /WEDNESDAY THROUGH WEDNESDAY NIGHT/...
SURFACE LOW PRESSURE MOVES OFFSHORE AND BEGINS TO STRENGTHEN AS IT
REACHES THE GULF STREAM. WINDS STRENGTHEN TO AROUND 15-20 MPH WITH
HIGHER GUSTS AS THE PRESSURE GRADIENT BETWEEN THE STRENGTHENING
LOW AND HIGH PRESSURE OVER THE OHIO VALLEY. WRAPAROUND RAINFALL
LIKELY AT TIMES OVER EASTERN MD AND PORTIONS OF VA. UPSLOPE RAIN
WILL DEVELOP OVER THE POTOMAC HIGHLANDS AND CONTINUE WEDNESDAY
NIGHT. LOOKS LIKE OVERNIGHT TEMPS WILL FAVOR LIQUID RAIN OVER MOST
OF THE HIGHLANDS...BUT THE HIGHEST ELEVATIONS IN GRANT...PENDLETON
AND HIGHLAND MAY SEE SNOW MIXED IN. LOW TEMPS IN THE 40S ACROSS
MOST OF THE FORECAST AREA.
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
BLUSTERY CONDITIONS WILL CONTINUE INTO THE DAY THURSDAY AS SURFACE 
LOW PRESSURE  SLOWLY SLIDES UP THE NEW ENGLAND COAST. DOWNSLOPING OF 
NORTHEASTERLY WINDS WILL ELIMINATE POPS LOCALLY DURING THE DAY 
THURSDAY EVERYWHERE EXCEPT THE POTOMAC HIGHLANDS...WHERE UPSLOPE 
RAIN IS POSSIBLE...AND THE FAR NORTHEASTERN PORTION OF THE CWA ALONG 
THE CHESAPEAKE BAY. 
HIGH PRESSURE WILL BEGIN TO FILL IN THURSDAY NIGHT AND WINDS WILL BE 
WEAKER FRIDAY. THE REST OF THE LONG TERM PERIOD WILL SEE QUIET/DRY 
WEATHER AS BROAD SURFACE HIGH PRESSURE MOVES OVERHEAD AND UPPER 
LEVEL RIDGING KEEPS PLENTY OF SUNSHINE ACROSS THE AREA. EXPECT TEMPS 
THIS WEEKEND TO BE RIGHT AROUND NORMAL...WITH HIGHS MOSTLY IN THE 
MID-60S...AND TEMPS EARLY NEXT WEEK TO BE JUST A FEW DEGREES ABOVE 
NORMAL. 
&&
.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
SCATTERED AREAS OF RAIN ARE DEVELOPING TO THE WEST...AND WILL MOVE
INTO THE WASHINGTON/BALTIMORE TERMINALS BY THIS EVENING. PERIODS
OF MVFR VSBYS LIKELY WITH RAIN. CIGS LOWER TO MVFR TONIGHT.
PERIODS OF IFR PSBL AS WELL AS LOW PRESSURE MOVES ACROSS THE
REGION BRINGING ADDITIONAL RAINFALL. LIGHT WESTERLY WINDS THIS
AFTN AND EVENING...BECG NW AND INCREASING TO AROUND 10KT
OVERNIGHT. LOWER CIGS EXPECTED TO PERSIST WEDNESDAY...AND PERIODIC
RAINFALL WILL BE POSSIBLE. GUSTY NW WINDS EXPECTED...UP TO 20-25KT
BY THE AFTERNOON. 
THU...VFR. NW WINDS GUSTING TO 20-25KT.
FRI...VFR. NW WINDS AROUND 1OKT.
CONFIDENCE IS LOW IN THE OCCURRENCE OF AVIATION HAZARDS OVER THE
WEEKEND AS HIGH PRESSURE BUILDS IN.
CLDY WED NGT BUT CIGS XPCTD TO BE VFR. BRZY NW WINDS XPCTD WED NGT
AND THU. VFR/NO PROBS FRI AND SAT.
&&
.MARINE...
LIGHT WINDS LATE THIS AFTERNOON. RAIN WILL MOVE INTO THE WATERS
LATE THIS AFTERNOON AND EVENING...WITH POTENTIAL FOR A FEW
THUNDERSTORMS. WINDS BECOME N-NW AND INCREASE OVERNIGHT...WITH
SCA GUSTS LIKELY BY EARLY WEDNESDAY MORNING. POTENTIAL CONTINUES
FOR GALES WEDNESDAY NIGHT AS LOW PRESSURE STRENGTHENS OFF THE
NJ/DELMARVA SHORE. MODEL FORECASTS ARE MARGINAL FOR GALES...SO FOR
NOW OPTED TO EXTEND SCA THROUGH WEDNESDAY NIGHT WITH GUSTS LIKELY
TO REACH 30KT IN SOME PARTS OF CHES BAY AT LEAST. 
A SMALL CRAFT ADVISORY WILL LIKELY BE NEEDED THURSDAY THROUGH FRIDAY 
AND POSSIBLY INTO FRIDAY NIGHT IN GUSTY NORTHEASTERLY WINDS AS LOW 
PRESSURE MOVES UP THE NORTHEAST COAST. WINDS MAY APPROACH GALE FORCE 
THURSDAY AFTERNOON OVER THE WATERS...THOUGH CURRENTLY THINK THEY 
WILL STAY MOSTLY IN THE MID TO UPPER 20 KNOT RANGE.
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...NONE.
VA...NONE.
WV...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 6 AM WEDNESDAY TO 6 AM EDT THURSDAY 
     FOR ANZ530>543.
&&
$$
SYNOPSIS...KCS
NEAR TERM...KCS
SHORT TERM...KCS
LONG TERM...CEB
AVIATION...KCS/CEB
MARINE...KCS/CEB