783
FXUS61 KLWX 161937
AFDLWX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
337 PM EDT SAT AUG 16 2025
SYNOPSIS
HIGH PRESSURE WILL EXTEND FROM THE MID ATLANTIC TO NEW ENGLAND
THROUGH SUNDAY. A COLD FRONT WILL PUSH INTO THE AREA SUNDAY
NIGHT INTO MONDAY MORNING BEFORE STALLING OVER THE REGION
THROUGH WEDNESDAY. THE FRONT WILL PUSH SOUTH OF THE AREA LATER
IN THE WEEK AS HIGH PRESSURE BUILDS TO THE NORTH.
NEAR TERM /THROUGH TONIGHT/
WEAK HIGH PRESSURE EXTENDS FROM THE MID ATLANTIC TO NEW ENGLAND.
GRADIENTS ARE WEAK AT THE SURFACE AND ALOFT, RESULTING IN LIGHT
WIND FIELDS. A RELATIVELY MOIST AIRMASS REMAINS IN PLACE, WITH
PRECIPITABLE WATER VALUES OF 1.2-1.6 INCHES, ALTHOUGH THERE IS A
DRY LAYER ALOFT. SO FAR TODAY, CONVECTION HAS BEEN FOCUSED ALONG
A THETA-E RIDGE AND LOW LEVEL CONVERGENCE AXIS STRADDLING THE
BLUE RIDGE AND CATOCTIN MOUNTAINS. THIS AXIS IS FORECAST TO
WEAKEN, AND MANY OF THE STORMS HAVE DISSIPATED OVER THE LAST
HOUR AS OUTFLOWS HAVE OUTPACED THE SLOW STORM MOTIONS. A SUBTLE
SHORTWAVE IS APPROACHING FROM THE NORTHWEST, AND THIS MAY BE
ENOUGH TO FIRE OFF MORE SCATTERED SHOWERS AND THUNDERSTORMS
ACROSS THE HIGHER TERRAIN BETWEEN THE BLUE RIDGE AND ALLEGHENY
FRONT. POOR LAPSE RATES AND THE DRY AIR ALOFT MAY CAUSE MOST
STORMS TO STRUGGLE GROWING. HOWEVER, STRONGER UPDRAFTS COULD
RESULT IN LOCALIZED GUSTY WINDS AS THEY COLLAPSE DUE TO
FAVORABLE DCAPE. OVERALL THESE OUTFLOWS SHOULD LIMIT STORM
LONGEVITY, BUT EFFICIENT RAIN PROCESSES COULD RESULT IN A QUICK
1-2.5 INCHES, AND THAT COULD CAUSE SOME FLOODING CONCERNS IF IT
WERE TO FALL OVER A SENSITIVE BASIN/URBANIZED AREA. ANY STORMS
SHOULD DISSIPATE QUICKLY WITH SUNSET. AFTERNOON TEMPERATURES
RANGE FROM THE MID 80S TO AROUND 90.
SKIES SHOULD BECOME MOSTLY CLEAR OVERNIGHT WITH LIGHT WINDS.
THIS WILL FAVOR PATCHY FOG DEVELOPMENT AGAIN, ESPECIALLY ALONG
THE RIVER VALLEYS WEST OF THE BLUE RIDGE. OVERNIGHT LOWS WILL
RANGE FROM THE MID 60S TO MID 70S.
SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/
THE HIGH REMAINS IN PLACE SUNDAY MORNING, THOUGH THE CENTER WILL
START TO MOVE EAST. THIS WILL ALLOW WINDS TO BECOME MORE
SOUTHERLY, AND THEN WESTERLY IN SOME LOCATIONS AS A SURFACE
TROUGH DEVELOPS IN THE LEE OF THE APPALACHIANS. THE LOSS OF
MARINE INFLUENCE WILL ALLOW FURTHER WARMING OF THE AIRMASS, WITH
HIGHS REACHING THE LOWER TO MID 90S ACROSS MUCH OF THE AREA. DEW
POINTS MAY TEND TO MIX DOWN WITH SOME RESIDUAL DRY AIR ALOFT,
BUT SOME LOCATIONS COULD STILL BE NEAR 100 FOR THE HEAT INDEX.
A SHORTWAVE TROUGH WILL PASS TO THE NORTH DURING THE AFTERNOON,
HELPING TO SEND A COLD FRONT SOUTHWARD TOWARD THE AREA. THE
FORCING FROM THE TROUGH ONLY GLANCES THE AREA, AND THE FRONT
WON'T APPROACH UNTIL LATE IN THE DAY. HOWEVER, THERE HAS BEEN
INCREASING AGREEMENT IN GUIDANCE FOR AT LEAST SOME SCATTERED
SHOWERS AND THUNDERSTORMS TO MOVE INTO NORTH/NORTHWESTERN PARTS
OF THE AREA BY MID TO LATE AFTERNOON. THERE IS STILL SOME
UNCERTAINTY WITH HOW FAR SOUTHEAST STORMS MAKE IT BEFORE LOSS OF
DAYTIME HEATING CAUSES A WEAKENING TREND. IT'S POSSIBLE FUTURE
FORECASTS MAY NEED TO INCREASE POPS A BIT INTO THE METRO AREAS.
SPC HAS INTRODUCED A MARGINAL RISK FOR POTENTIAL WIND DAMAGE
WITH MULTICELL CLUSTERS, BUT THE OVERALL CAPE, SHEAR, AND DCAPE
PARAMETER SPACE ARE NOT SUGGESTIVE OF A NOTABLE SEVERE WEATHER
THREAT. THE STORMS SHOULD BE SOMEWHAT PROGRESSIVE, BUT LOCALLY
HEAVY RAIN COULD OCCUR AS PRECIPITABLE WATER MAXIMIZES AHEAD OF
THE FRONT.
UNCERTAINTY INCREASES INTO MONDAY WITH GUIDANCE DIFFERING ON
FRONTAL POSITION (OVERHEAD OR PUSHING SOUTH OF THE AREA) AND
WHAT KIND OF FORCING COULD EXIST ALONG THE BOUNDARY THAT MAY AID
IN THE GENERATION OF MORE SHOWERS AND THUNDERSTORMS. THE CURRENT
NBM FORECAST MAY END UP TOO CONSERVATIVE (IN CLOUDS AND POPS),
AS THERE ARE INDICATIONS AT LEAST PORTIONS OF THE AREA MAY END
UP RATHER CLOUDY AND SHOWERY THROUGH THE DAY. REGARDLESS,
TEMPERATURES DO TAKE A DOWNWARD TREND. MOST AREAS WILL TOP OUT
IN THE 80S, THOUGH SOME PLACES COULD STAY IN THE 70S. WITH THE
FRONTAL ZONE POTENTIALLY STILL NEARBY AND AN INCREASING MARINE
INFLUENCE ON NORTHEAST WINDS, SOME RAIN SHOWERS COULD CONTINUE
INTO MONDAY NIGHT.
LONG TERM /TUESDAY THROUGH SATURDAY/
UPPER RIDGING WILL BUILD OVER THE ROCKIES EARLY NEXT WEEK, WHICH
WILL CAUSE FLOW ALOFT DOWNSTREAM TO TURN NORTHWESTERLY. AT THE
SURFACE, HIGH PRESSURE IS EXPECTED TO REMAIN IN PLACE OFF THE NEW
ENGLAND COASTLINE. THE COMBINATION OF NORTHWESTERLY FLOW ALOFT AND
HIGH PRESSURE TO OUR NORTHEAST AT THE SURFACE SHOULD RESULT IN LOW
COVERAGE OF AFTERNOON THUNDERSTORMS AND NEAR TO SLIGHTLY BELOW
NORMAL TEMPERATURES THROUGHOUT THE LONG TERM PERIOD. THE BEST CHANCE
FOR STORMS CURRENTLY LOOKS TO BE ON WEDNESDAY AS A DISTURBANCE ALOFT
DESCENDS DOWN IN NORTHWESTERLY FLOW FROM THE GREAT LAKES.
TEMPERATURES WILL RUN NEAR TO SLIGHTLY BELOW NORMAL, WITH HIGHS IN
LOW TO MID 80S AND LOWS IN THE 60S TO NEAR 70.
AVIATION /19Z SATURDAY THROUGH THURSDAY/
EARLIER STRATUS HAS MIXED OUT INTO A CUMULUS FIELD. SCATTERED
THUNDERSTORM COVERAGE HAS SHIFTED WEST OF THE BLUE RIDGE, SO
THESE IMPACTS WILL LIKELY REMAIN LIMITED TO MRB, ALTHOUGH A
SHOWER COULD DRIFT NEAR CHO TOWARD EVENING. SOUTHEAST TO SOUTH
WINDS SHOULD BECOME CALM AFTER SUNSET. THIS WILL SET THE STAGE
FOR PATCHY FOG DEVELOPMENT DURING THE SECOND HALF OF THE NIGHT,
MAINLY NEAR CHO AND MRB.
MOST OF SUNDAY REMAINS DRY WITH VFR CONDITIONS AND LIGHT SOUTH
TO WEST WINDS AS A SURFACE TROUGH DEVELOPS. SCATTERED
THUNDERSTORMS WILL APPROACH FROM THE NORTHWEST DURING THE
AFTERNOON AHEAD OF A COLD FRONT. MRB HAS THE HIGHEST CHANCE OF
SEEING A STORM, BUT A FEW STORMS COULD HOLD TOGETHER INTO THE
METRO AREAS TOWARD EVENING.
LOW CEILINGS MAY DEVELOP IF THE FRONT PUSHES SOUTH OF THE AREA
SUNDAY NIGHT. THE FRONTAL POSITION REMAINS UNCERTAIN INTO
MONDAY. THUNDERSTORMS WILL BE POSSIBLE SOUTH OF THE FRONT
(HIGHEST CHANCE AT CHO), WHILE LOW CLOUDS AND SHOWERS ARE
POSSIBLE TO THE NORTH.
SUB-VFR CEILINGS APPEAR POSSIBLE WITHIN EAST TO SOUTHEASTERLY LOW-
LEVEL FLOW EARLY TUESDAY MORNING, AND THEN AGAIN LATE TUESDAY NIGHT
INTO EARLY WEDNESDAY MORNING.
MARINE
BACKGROUND WIND FIELDS REMAIN BLOW SMALL CRAFT ADVISORY LEVELS
THROUGH AT LEAST SUNDAY. ANY CONVECTIVE CHANCES STAY OUT ACROSS
THE MOUNTAINS TODAY. A BROKEN LINE OF SHOWERS AND THUNDERSTORMS
ARE POSSIBLE AS A COLD FRONT APPROACHES SUNDAY EVENING, SOME OF
WHICH COULD HAVE GUSTY WINDS. AHEAD OF THESE STORMS, SOUTHERLY
CHANNELING MAY APPROACH ADVISORY LEVELS ON THE MIDDLE BAY. BY
MONDAY, POST-FRONTAL NORTHEASTERLY FLOW ENSUES WITH GUSTS
AROUND 10 TO 15 KNOTS, PERHAPS APPROACHING ADVISORY CRITERIA BY
LATE IN THE DAY. IF THE FRONT DOESN'T PUSH FAR ENOUGH SOUTH,
HOWEVER, THUNDERSTORMS COULD DEVELOP AGAIN MONDAY AFTERNOON.
SUB-SCA LEVEL EAST TO SOUTHEASTERLY WINDS ARE EXPECTED ON TUESDAY
AND WEDNESDAY. HOWEVER, WINDS MAY INCREASE SOME DURING THE
MIDDLE OF THE WEEK AS GRADIENTS TIGHTEN WITH ERIN OFFSHORE.
TIDES/COASTAL FLOODING
ELEVATED TIDAL ANOMALIES CONTINUE THROUGH THE WEEKEND WITH SOME
UPTICK FORECAST DUE TO ONSHORE WINDS. ANNAPOLIS IS FORECAST TO
REACH MINOR FLOOD TONIGHT AND SUNDAY NIGHT. WHILE OTHER
LOCATIONS AREN'T CURRENTLY FORECAST TO FLOOD, SOME COULD COME
CLOSE, ESPECIALLY SUNDAY EVENING. A PASSING COLD FRONT SHOULD
REDUCE WATER LEVELS SLIGHTLY HEADING INTO MONDAY.
LWX WATCHES/WARNINGS/ADVISORIES
DC...NONE.
MD...COASTAL FLOOD ADVISORY FROM 10 PM THIS EVENING TO 4 AM EDT
SUNDAY FOR MDZ014.
VA...NONE.
WV...NONE.
MARINE...NONE.
SYNOPSIS...ADS
NEAR TERM...ADS
SHORT TERM...ADS
LONG TERM...KJP
AVIATION...ADS/KJP
MARINE...ADS/KJP
TIDES/COASTAL FLOODING...ADS
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