379
FXUS61 KLWX 111335
AFDLWX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
935 AM EDT THU SEP 11 2025
SYNOPSIS
HIGH PRESSURE WILL REMAIN TO OUR NORTH TONIGHT AS A WAVE OF LOW
PRESSURE PASSES OFFSHORE. A DRY FRONT WILL DISSIPATE AS IT
APPROACHES ON THURSDAY, THEN ANOTHER AREA OF HIGH PRESSURE WILL
DRIFT TOWARD NEW ENGLAND THIS WEEKEND, RESULTING IN CONTINUED
DRY CONDITIONS.
NEAR TERM /THROUGH TONIGHT/
VISIBLE SATELLITE IMAGERY AS OF 9:30AM SHOWS CLOUD COVER SLOWLY
ERODING FROM WEST TO EAST WITH CLOUDY SKIES MAINLY CONFINED TO
THE I-95 CORRIDOR. AS SURFACE LOW PRESSURE CONTINUES TO SHIFT
OFF SHORE, DRY AIR WILL FILTER IN OVERHEAD LEADING TO SUNNY
SKIES THIS AFTERNOON. THE 12Z KIAD SOUNDING ALREADY SHOWS DRY
AIR ALOFT WITH A MID-LEVEL RELATIVE HUMIDITY VALUE OF 39%
COMPARED TO 69% LAST NIGHT. NO CHANGES WERE MADE TO THE FORECAST
WITH THE PREVIOUS DISCUSSION LOCATED BELOW.
WHILE LOW PRESSURE IS PULLING AWAY FROM THE MID ATLANTIC COAST,
NORTH TO NORTHEAST WINDS CONTINUE TO ADVECT MOISTURE AND CLOUDS
INTO THE EASTERN HALF OF THE CWA. THE SHALLOW NATURE OF THIS
MOISTURE COMBINED WITH WEAK LIFT CONTINUES TO RESULT IN PATCHY
DRIZZLE/LIGHT SHOWERS, AS SEEN VIA RADAR AND REGIONAL
OBSERVATIONS. GIVEN THE PERSISTENCE OF THESE SHOWERS ALL NIGHT,
AND MODEL SUPPORT, THESE SHOWERS WILL LIKELY CONTINUE THROUGH
MID-MORNING, THOUGH GRADUALLY SHIFTING EASTWARD AS DRIER AIR
FILTERS IN. THIS WILL ALSO BEGIN TO PUSH CLOUDS TOWARDS THE
SOUTH AND EAST BY MID-LATE MORNING, WITH MOST AREAS SEEING SUN
AFTER NOON. HIGHS TODAY WILL REACH THE UPPER 70S TO LOW 80S
(UPPER 60S TO LOW 70S IN THE MOUNTAINS).
SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/
HIGH PRESSURE REMAINS TO THE NORTH ON FRIDAY WITH MOSTLY SUNNY
SKIES AND TEMPERATURES RETURNING CLOSER TO AVERAGE FOR THIS TIME
OF YEAR. HIGHS WILL BE IN THE LOWER 80S (UPPER 60S TO 70S IN THE
MOUNTAINS). WINDS SHOULD REMAIN LIGHT AND OUT OF THE NORTHEAST.
EXPECT SOME PATCHY FOG TO DEVELOP IN THE SHELTERED VALLEYS AND AREAS
THAT FAVOR RADIATIONAL COOLING DURING THE OVERNIGHT HOURS. LOW
TEMPERATURES WILL GENERALLY BE IN THE 50S. LOWER 60S ALONG THE
WATERS AND IN THE METROS.
WINDS TURN OUT OF THE SOUTH ON SATURDAY, REMAINING LIGHT, AS
HIGH PRESSURE SHIFTS A BIT TOWARDS THE EAST. A SUBTLE MID-LEVEL
HEIGHT RISE WILL RESULT IN SLIGHTLY WARMER TEMPERATURES SATURDAY
AFTERNOON, BUT OVERALL THE PATTERN REMAINS VERY SIMILAR.
OVERNIGHT LOWS JUMP A FEW DEGREES SATURDAY NIGHT IN RESPONSE TO
THE SOUTHERLY FLOW.
LONG TERM /SUNDAY THROUGH WEDNESDAY/
OVERALL THE EXTENDED PERIOD REMAINS QUIET WITH DRY CONDITIONS
AND NEAR NORMAL TEMPERATURES EXPECTED THROUGH THE MIDDLE PART OF
NEXT WEEK. SYNOPTICALLY, WILL CONTINUE TO WATCH THE EXPANSION
OF A 500 MB UPPER LEVEL RIDGE OVER THE CENTRAL U.S. MEANWHILE,
THE UPPER TROUGH OVER THE AREA WILL PUSH EASTWARD AS THE RIDGE
EXPANDS INTO THE OHIO RIVER VALLEY AND GREAT LAKES REGION. AT
THE SURFACE, HIGH PRESSURE OVER NORTHERN NEW ENGLAND WILL REMAIN
WEDGED DOWN THE EASTERN FACE OF THE APPALACHIANS. THIS WILL
LEAD TO DRY AND TRANQUIL CONDITIONS THIS WEEKEND WITH HIGH
TEMPERATURES RUNNING NEAR NORMAL FOR MOST LOCATIONS EAST OF THE
MOUNTAINS. A SLIGHT UPTICK IN HUMIDITY MAY BE NOTED WITH LIGHT
EASTERLY ONSHORE FLOW BANKING ATLANTIC MOISTURE EAST OF THE BLUE
RIDGE. SKIES WILL TREND MOSTLY SUNNY TO PARTLY CLOUDY SATURDAY
WITH HIGHS IN UPPER 70S AND LOW 80S (UPPER 60S AND LOW 70S
MOUNTAINS). MOSTLY CLEAR TO PARTLY CLOUDY SKIES ARE EXPECTED
SATURDAY NIGHT WITH LOWS IN THE MID 50S TO LOW 60S
(DEEPER/SHELTERED RIVER VALLEYS COULD FALL INTO THE UPPER 40S).
SOME VALLEY FOG IS POSSIBLE LATE SATURDAY NIGHT INTO SUNDAY
MORNING GIVEN THE ADDED MOISTURE FROM ONSHORE FLOW. ANY FOG
WOULD LIKELY MIX OUT AS THE INVERSION BREAKS SUNDAY MID MORNING.
AN UPPER LEVEL LOW PRESSURE SYSTEM WILL TRACK INTO THE NORTHEASTERN
U.S SUNDAY AND MONDAY WITH A BROAD 500 MB TROUGH DEEPENING OVERHEAD.
THE LOW PRESSURE SYSTEM WILL DRAG A COLD FRONT ACROSS THE MID-
ATLANTIC AND NORTHEAST BRINGING RAIN CHANCES BACK TO THE REGION.
THERE STILL REMAIN SOME UNCERTAINTY IN REGARDS TO THE COVERAGE OF
RAIN AND INTENSITY GIVEN THE RESIDUAL DRY AIRMASS/HIGH PRESSURE
SYSTEM REMAINING NEARBY. FOR NOW, LOOKING AT CHANCES OF 15 TO 20
PERCENT MAINLY ALONG AND NORTH OF I-66/US-50 SUNDAY AFTERNOON INTO
MONDAY MORNING AS MAIN FORCING TRACKS NORTH OF THE REGION. LOCATIONS
THAT DO SEE RAIN WILL MOST LIKELY SEE ONLY A FEW ONE HUNDREDTHS OF
AN INCH WHICH DOESN'T HELP WITH ONGOING DROUGHT CONCERNS. ELSEWHERE,
MAINLY DRY CONDITIONS ARE EXPECTED WITH INCREASED CLOUD COVER AS THE
SYSTEM PASSES THROUGH. HIGHS SUNDAY WILL REACH INTO THE UPPER 70S
AND LOW TO MID 80S (MOUNTAINS LOW 70S). LOWS SUNDAY NIGHT WILL FALL
BACK INTO THE 50S AND 60S.
BROAD CANADIAN HIGH PRESSURE OVER THE GREAT LAKES WEDGES BACK INTO
THE AREA LATE MONDAY INTO TUESDAY BEFORE SETTLING NEARBY MIDWEEK.
TRANQUIL WEATHER IS EXPECTED AS A RESULT ALONG WITH NEAR NORMAL
TEMPERATURES ACROSS THE REGION. EXPECT HIGH TEMPS IN THE UPPER 70S
AND LOW 80S WITH OVERNIGHT LOWS IN THE 50S.
AVIATION /14Z THURSDAY THROUGH MONDAY/
MID-LEVEL CLOUDS ARE STILL GRADUALLY PUSHING EAST, BUT VERY
SLOWLY AT THIS TIME. MEANWHILE, A SHIELD OF IFR TO LOW-END MVFR
CIGS HAS PUSHED ALMOST ALL THE WAY TO THE BLUE RIDGE THIS
MORNING. THIS IS AT LEAST TEMPORARILY DROPPING CIGS AT MOST
AIRPORTS (ASIDE FORM MRB) THIS MORNING. THE DECK IS GENERALLY
BKN, BUT AT TIMES WILL SCATTER OUT BEFORE FILLING BACK IN.
EXPECT PERIODS OF IFR TO MVFR CIGS TO CONTINUE THROUGH EARLY
MORNING AS A RESULT, PERHAPS EVEN LONGER. MODEL GUIDANCE HAS
BEEN OF LITTLE HELP IN DETERMINING HOW FAST THESE WILL SCOUR OUT
THIS MORNING. PATCHY DRIZZLE CONTINUES TO AFFECT THE AREA TOO,
AND EVEN SOME HEAVIER SHOWERS UP IN NORTHEAST MD THAT IS
AFFECTING BWI AND MTN.
MRB AND CHO MAY ULTIMATELY SEE SOME FOG BEFORE SUNRISE THIS
MORNING UNDER MOSTLY CLEAR SKIES, ALTHOUGH IT IS UNCERTAIN HOW
FAR VISIBILITY DROPS. FOG COULD FORM AT IAD IF SKIES CAN CLEAR
BEFORE DAWN, WHICH IS TRYING TO HAPPEN AT THIS TIME.
VFR CONDITIONS RETURN FOR ALL AREAS LATER THIS MORNING AND
LIKELY TO CONTINUE THROUGHOUT THE WEEKEND, OUTSIDE OF ANY
MOUNTAIN/VALLEY LATE NIGHT/EARLY MORNING FOG. WINDS OUT OF THE N
TO NE TODAY AND FRIDAY WILL TURN S TO SW THIS WEEKEND. WINDS
SHIFT BACK OUT OF THE NORTH AND NORTHWEST EARLY NEXT WEEK AT
LESS THAN 10 KTS.
MARINE
NO MARINE HAZARDS ARE EXPECTED THROUGH SATURDAY NIGHT AS HIGH
PRESSURE RETURNS TO THE REGION. WINDS NORTH TO NORTHEAST 5 TO
10 KNOTS GUSTS TO 15 KNOTS TODAY AND FRIDAY, BEFORE TURNING OUT
OF THE SOUTH ON SATURDAY.
SCA CONDITIONS ARE POSSIBLE OVER MIDDLE AND LOWER PORTIONS OF THE
BAY SUNDAY AFTERNOON INTO MONDAY. SUB-SCA LEVEL WINDS ARE EXPECTED
TUESDAY AND WEDNESDAY AS WEDGING HIGH PRESSURE SITS NEARBY.
TIDES/COASTAL FLOODING
DUE TO LOW PRESSURE MOVING OFF THE COAST, TIDES WILL REMAIN
ELEVATED IN THE COMING DAYS. ANOMALIES ARE TRICKLING DOWN A
LITTLE AS THE LOW MOVES FARTHER OFFSHORE. HOWEVER, SLACKENING
WINDS MAY ALLOW SOME WATER TO SLOSH NORTHWARD TODAY AND FRIDAY,
WITH MINOR FLOODING POSSIBLE IN SOME LOCATIONS DURING THE
AFTERNOON AND EVENING. THE PATTERN DOESN'T CHANGE APPRECIABLY,
SO SPOTTY MARGINALLY MINOR FLOODING MAY CONTINUE INTO THE
WEEKEND, ESPECIALLY SINCE WINDS MAY EVENTUALLY TURN SOUTHERLY.
LWX WATCHES/WARNINGS/ADVISORIES
DC...NONE.
MD...NONE.
VA...NONE.
WV...NONE.
MARINE...NONE.
SYNOPSIS...EST
NEAR TERM...AVS/CJL
SHORT TERM...ADS/CJL
LONG TERM...EST
AVIATION...ADS/CJL/EST
MARINE...CJL/EST
TIDES/COASTAL FLOODING...CJL/EST
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