Area Forecast Discussion
Issued by NWS Sterling, VA

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FXUS61 KLWX 300754
AFDLWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
354 AM EDT THU OCT 30 2014

.SYNOPSIS...
HIGH PRESSURE LOCATED OVER THE OHIO VALLEY WILL MOVE NORTHEAST
INTO NEW ENGLAND THROUGH TONIGHT. A LOW PRESSURE SYSTEM WILL
DESCEND FROM THE GREAT LAKES TO THE CAROLINAS FRIDAY INTO SATURDAY
MORNING. THIS LOW WILL TRACK NORTHEAST AWAY FROM THE REGION
SATURDAY NIGHT INTO SUNDAY. MORE HIGH PRESSURE WILL THE BUILD INTO
MONDAY FOLLOWED BY ANOTHER COLD FRONT WEDNESDAY.
&&

.NEAR TERM /THROUGH FRIDAY/...
AREAS OF FOG HAVE DEVELOPED OVER PORTIONS OF THE VA PIEDMONT AND
NORTHERN MD OVERNIGHT IN LOCATIONS WHERE LOW LEVEL MOISTURE AND
CLEARING SKIES INTERSECTED AFTER SUNSET. WINDS WERE ABLE TO GO CALM
AND WITHOUT STRONG ADVECTION OF DRIER AIR...THIS FOG IS EXPECTED TO
LAST A LITTLE PAST SUNRISE. THE DENSE FOG SEEMS TO BE LOCALIZED AND
SHALLOW IN NATURE SO HAVE BEEN COVERING WITH NOWCASTS...BUT WILL
CONTINUE TO MONITOR THE LATEST OBSERVATIONS.

OTHERWISE HIGH PRESSURE WILL BUILD EASTWARD FROM THE OHIO VALLEY
THROUGH TODAY AND TONIGHT. DRY CONDITIONS WILL PREVAIL WITH ONLY
SOME DIURNAL CUMULUS. IN THE MUCH CHILLIER AIRMASS BEHIND THE
DEPARTED FRONT...HIGH TEMPERATURES WILL STRUGGLE TO REACH 60F.
FAIRLY LOW SPREAD IN GUIDANCE FOR LOW TEMPERATURES TONIGHT...RANGING
FROM MID 30S IN THE MOUNTAINS TO LOWER 40S IN THE METROS/BY THE BAY.

FRIDAY...UPPER LEVEL PATTERN AMPLIFICATION WILL BE UNDERWAY AS A
SHORTWAVE TROUGH DIGS ALMOST DUE SOUTHWARD FROM THE GREAT LAKES.
SURFACE HIGH PRESSURE WILL CONTINUE TO INFLUENCE THE AREA FOR MOST
OF THE DAY THE ORIENTATION OF THE LOW LEVEL WIND FIELDS DOES NOT
ALLOW RETURN FLOW TO DEVELOP...SO EXPECT SIMILAR BELOW NORMAL
TEMPERATURES COMPARED TO THURSDAY. CLOUDS WILL ALSO INCREASE FROM
THE WEST...WHICH MAY ALSO HINDER TEMPERATURES. AS THE LOW PRESSURE
SYSTEM NEARS...SOME SHOWERS MAY SPREAD INTO THE WV/MD MOUNTAINS BY
LATE AFTERNOON. THIS APPEARS SLIGHTLY SLOWER THAN PREVIOUS
FORECASTS.
&&

.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY NIGHT/...
THE WKND FCST WL REVOLVE ARND S/WV ENERGY PLUNGING INTO THE SERN
CONUS FRI NGT-SAT MRNG...CARVING OUT A DP UPR TROF/CUTOFF LOW...
INDUCING CYCLOGENESIS LT SAT...WHICH WL HEAD OUT INTO THE ATLC SAT
NGT-SUN. WHILE MDL GDNC CONTS TO DIFFER ON SPECIFICS...THE OVERALL
SYNOPTIC PTTN DESCRIBED ABV SEEMS TO BE NARROWING IN ON A SOLN...
ALBEIT AN ANOMOLOUS ONE.

WL FLLW A SCENARIO WHERE MOST OF THE ENERGY WL BE DIPPING W OF THE
CWFA FRI NGT...WHICH WL KEEP POPS HIGH W OF THE BLURDG...BUT LOW IN
THE E. GFS QPF VERBATIM ACTUALLY PAINTS THE I-95 CRRDR DRY ATTM. AM
NOT FEELING THAT CONFIDENT IN ABSOLUTES...AND HV OPTED TO KEEP CHC
POPS IN THE E...BUT EMPHASIZED AFTR MIDNGT TIMING. THIS ENERGY WLL
SHIFT OFFSHORE ON SAT...TO THE S OF THE AREA. ONCE AGAIN...THIS WL
KEEP THE AXIS OF HEAVIEST PCPN AWAY FM THE IMMEDIATE AREA...THIS
TIME TO THE SOUTH. HV LKLY POPS OKV-METRO DC-DMH SWD. THEN TAPER
POPS OFF AS LOW PULLS AWAY.

DUE TO THE DEPTH OF THE LOW/EXTENT OF HGT FALLS...PTYPE BECOMES AN
ISSUE. WL PRESERVE PRVS FCSTS...WHICH CONFINES ANY MIX/SNW TO THE
APLCNS...SPCLY THE WRN SLOPES. IT WUD TAKE AN EXTREME EVENT TO BRING
ANYTHING OTHER THAN RA E OF THERE IN ELY NOV.

STILL LOOKING AT WINDY CONDS SAT AFTN-NGT AS THE LOW DEEPENS AND
PULLS AWAY. GDNC SUGGESTING SUSTAINED WNDS ARND 20 MPH...AND GUSTS
CUD EASLIY REACH 30-35 MPH. OF COURSE...THE EXACT EVOLUTION OF THE
SYSTEM WL DETERMINE THOSE DETAILS.

TOOK MIN-T UP A CPL DEGF FRI NGT DUE TO POOR RADL COOLING CONDS. SAT
NGT WILL BE PRELY BASED ON CAA. CHGS MINIMAL. IT MAY SPELL THE END
OF THE GROWING SEASON FOR MANY AREAS W OF THE BLURDG. MAXT SAT WL BE
UNSEASONABLY CHILLY. MOS HAS A DECENT HANDLE ON IT...LWR 50S E OF
THE BLURDG AND MID-UPR 40S W.
&&

.LONG TERM /MONDAY THROUGH WEDNESDAY/...
HIGH PRESSURE MOVES SOUTH OF THE REGION SO NORTHWEST WINDS BEHIND
THE FRONT GIVE WAY TO WAA FROM SOUTHERLY/SOUTHWESTERLY FLOW ON
TUESDAY. THIS WILL LEAD TO A GRADUAL WARMUP IN THIS PERIOD. A COLD
FRONT IS THEN LIKELY TO PUSH INTO THE REGION BY LATE TUESDAY INTO
WEDNESDAY HAVE INCLUDED A LOW CHANCE OF SHOWERS ALONG THE FRONT.
WENT WARMER ON TUESDAY GIVEN THE WAA AND 925 MB TEMPS APPROACHING
9C...GETTING THE REGION INTO THE 60S.
&&

.AVIATION /08Z THURSDAY THROUGH MONDAY/...
AREAS OF SHALLOW FOG HAVE PERSISTED OVERNIGHT AS LOW LEVEL MOISTURE
LINGERS WITH CALM WINDS. KCHO HAS REMAINED IFR OR LOWER MOST OF THE
NIGHT...WHILE KBWI/KIAD HAVE REPORTED PATCHES OF FOG AT TIMES. THIS
WILL CONTINUE THROUGH SUNRISE THEN GRADUALLY BURN OFF. OTHERWISE
HIGH PRESSURE WILL PROVIDE VFR CONDITIONS TODAY AND TONIGHT.
SCATTERED CUMULUS AROUND 4-5KFT WILL DEVELOP THIS AFTERNOON. SOME
STRATOCUMULUS AROUND THE SAME LEVEL COULD LINGER INTO THE OVERNIGHT
HOURS. DAYTIME WINDS WILL BE FROM THE NW AT LESS THAN 10KT BEFORE
DECOUPLING THIS EVENING.

FLGT RESTRICTIONS XPCTD THIS WKND AS UPR LVL ENERGY PASSES S OF
THE AREA...INITIATING LOPRES WHICH PASSES NE. MVFR SHUD GNLY
PREVAIL... BUT WUDNT RULE OUT LCL IFR FRI NGT-SAT. IN ADDITION...
WL HV WINDY CONDS /NW 20-30 KT/ SAT AFTN INTO SUN WHICH CUD AFFECT
OPS.
&&

.MARINE...
HIGH PRESSURE WILL AFFECT THE WATERS TODAY THROUGH FRIDAY. N TO NW
WINDS WILL PEAK AT 10-15KT.

A STORM SYSTEM WL AFFECT THE MARINE AREA THIS WKND. SCA CONDS LKLY
BY SAT...AND GLW PROBABLE FOR PORTIONS OF THE WATERS BY SAT AFTN
INTO SUN.
&&

.TIDES/COASTAL FLOODING...
A DEEP AREA OF LOW PRESSURE WILL CROSS THE CAROLINAS AND THEN
TRACK NORTHEAST THIS WEEKEND. THERE MAY BE A PERIOD OF HIGHER THAN
NORMAL TIDES FRI NIGHT INTO SAT...FOLLOWED BY BLOWOUT CONDITIONS
SAT AFTERNOON THROUGH SUNDAY.
&&

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

&&

$$
SYNOPSIS...HTS
NEAR TERM...ADS
SHORT TERM...HTS
LONG TERM...HTS/GAINES
AVIATION...ADS/HTS
MARINE...ADS/HTS
TIDES/COASTAL FLOODING...HTS







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