358
FXUS61 KLWX 171927
AFDLWX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
327 PM EDT SUN AUG 17 2025
SYNOPSIS
A COLD FRONT WILL PUSH INTO THE AREA TONIGHT. THE FRONT WILL
STALL OUT JUST TO THE SOUTH THROUGH WEDNESDAY, EVENTUALLY
PUSHING FARTHER SOUTH THURSDAY. HIGH PRESSURE WILL THEN RETURN
FROM THE NORTH THROUGH SATURDAY.
NEAR TERM /THROUGH TONIGHT/
COLD FRONT IS PUSHING SOUTHEAST FROM THE GREAT LAKES THIS
AFTERNOON. THERE ARE ALSO A COUPLE RIPPLES IN THE NORTHWEST FLOW
HELPING WITH CONVECTIVE INITIATION WITHIN A PREFRONTAL TROUGH.
DEEPER CONVECTION HAS BEEN CONFINED TO PA SO FAR, WITH A
STRONGER CLUSTER APPROACHING WESTERN MARYLAND, LIKELY NEAR THE
TAIL OF A PREVIOUS MCV. EXPECT THIS ACTIVITY TO DRIFT
SOUTHEASTWARD THROUGH THE REMAINDER OF THE AFTERNOON AND
EVENING, THOUGH A FEW SHOWERS OR STORMS COULD ALSO TRY TO POP UP
AHEAD OF IT. OUTSIDE OF THE HEAT AND HUMIDITY INDUCED
INSTABILITY, MOST OTHER PARAMETERS ARE MARGINAL AT BEST FOR
SEVERE THUNDERSTORMS. ANY STRONGER OR MORE ORGANIZED CLUSTERS
COULD HAVE A THREAT FOR LOCALIZED WIND DAMAGE, WITH A MARGINAL
RISK IN PLACE FROM SPC. STORMS SHOULD BE SOMEWHAT PROGRESSIVE,
SO WHILE DOWNPOURS COULD PRODUCE SOME LOCALIZED TOTALS OVER AN
INCH, FLOODING APPEARS UNLIKELY. TIMING WILL FAVOR THE EVENING
HOURS ALONG THE I-95 CORRIDOR, WITH ANY REMAINING STORMS EXITING
SOUTHERN MARYLAND AROUND MIDNIGHT. THE PRIMARY COLD FRONT WILL
LIKELY SURGE INTO THE AREA LATE TONIGHT. BEFORE THAT HAPPENS,
SOME OF THE WESTERN VALLEYS COULD HAVE SOME PATCHY FOG. LOWS
WILL RANGE FROM THE MID 60S TO MID 70S.
SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/
THE FRONT WILL STALL OUT NEARBY MONDAY AND TUESDAY, ALTHOUGH THE
CONSENSUS FAVORS JUST SOUTH OF THE AREA. HOWEVER, IT IS WORTH
NOTING THAT THERE IS ABOUT 15 DEGREES OF SPREAD BETWEEN THE
COOLEST AND WARMEST MODELS IN TERMS OF TEMPERATURES. THE
FORECAST FAVORS A MIDDLE GROUND FOR TEMPERATURES, BUT THIS STILL
RESULTS IN HIGHS FROM THE MID 70S TO LOWER 80S. LOW OVERCAST
CONDITIONS ALSO LIKELY DEVELOP, EXCEPT PERHAPS THE FAR SOUTHERN
PARTS OF THE CWA. NORTHEASTERLY WINDS MAY BE A BIT GUSTY IN THE
WAKE OF THE FRONT MONDAY. MORE SIGNIFICANT RAINS WILL LIKELY
REMAIN SOUTH OF THE AREA, BUT SOME OVERRUNNING SHOWERS AND
DRIZZLE WILL BE POSSIBLE THROUGH MONDAY NIGHT. SLIGHTLY DRIER
AIR ALOFT MAY LIMIT THIS POTENTIAL BY TUESDAY, ESPECIALLY WITH
NORTHEASTWARD EXTENT IN THE AREA. DEW POINTS WON'T SEE A LARGE
DECREASE BEHIND THE FRONT, AND COMBINED WITH THE CLOUD COVER,
OVERNIGHT LOWS WILL REMAIN IN THE 60S.
LONG TERM /WEDNESDAY THROUGH SUNDAY/
BY WEDNESDAY, WE'LL BE SITUATED BETWEEN A SHORTWAVE TROUGH
APPROACHING FROM THE NORTHWEST AND ERIN, WHICH IS FORECAST TO
TRACK WELL OFF THE CAROLINA COAST AT THAT TIME, PER THE LATEST
NHC FORECAST. THE APPROACHING SHORTWAVE WILL SUPPLY SOME WEAK LARGE
SCALE FORCING FOR ASCENT, WHILE COMPENSATING SUBSIDENCE ON THE
PERIPHERY OF ERIN'S CIRCULATION WILL HAVE THE OPPOSITE EFFECT. WHILE
MOST LOCATIONS SHOULD STAY DRY, A STRAY AFTERNOON SHOWER OR STORM
CAN'T BE COMPLETELY RULED OUT, ESPECIALLY ACROSS THE HIGHER TERRAIN,
WHERE TERRAIN CIRCULATIONS MAY ACT TO ENHANCE LOW-LEVEL
CONVERGENCE/LIFT. TEMPERATURES ARE EXPECTED TO REMAIN BELOW NORMAL,
WITH HIGHS IN THE UPPER 70S/LOW 80S FOR MOST.
THE AFOREMENTIONED SHORTWAVE TROUGH IS FORECAST TO PROGRESS OFF TO
OUR EAST ON THURSDAY, WHICH WILL PUSH ERIN FURTHER OUT TO SEA. WE'LL
BE LEFT WITH NORTHWESTERLY FLOW ALOFT AND A RELATIVELY WEAK SURFACE
PATTERN FOR THURSDAY AND FRIDAY. LIGHT WINDS AND NEAR TO SLIGHTLY
BELOW NORMAL TEMPERATURES ARE EXPECTED DURING THAT TIME, WITH HIGHS
IN THE LOW TO MID 80S AND LOWS IN THE 60S. MOST LOCATIONS SHOULD
STAY DRY, BUT A POPUP AFTERNOON SHOWER OR STORM COULD BE POSSIBLE,
ESPECIALLY TO THE WEST OF THE BLUE RIDGE.
HIGH PRESSURE WILL BECOME ESTABLISHED OFFSHORE BY SATURDAY.
SOUTHERLY FLOW AROUND THE HIGH WILL LEAD TO AN UPTICK IN LOW-LEVEL
MOISTURE, WITH DEWPOINTS CLIMBING BACK THROUGH THE 60S, AND
POTENTIALLY EVEN APPROACHING 70 DEGREES. MEANWHILE, A DEEP UPPER
TROUGH WILL START TO DIG SOUTHEASTWARD ACROSS THE GREAT LAKES. WINDS
ALOFT WILL START TO INCREASE LOCALLY IN RESPONSE TO THAT FEATURE. AS
LARGE SCALE ASCENT AHEAD OF THAT TROUGH STARTS TO OVERSPREAD THE
AREA, SHOWERS AND THUNDERSTORMS MAY BE POSSIBLE BY SATURDAY
AFTERNOON. SOME OF THESE STORMS COULD POTENTIALLY BE ON THE STRONGER
SIDE, AS SURFACE BASED INSTABILITY OVERLAPS WITH INCREASING FLOW
ALOFT.
AVIATION /19Z SUNDAY THROUGH FRIDAY/
VFR CONDITIONS CONTINUE THIS AFTERNOON UNTIL THE THREAT OF
THUNDERSTORMS ARRIVES. A PRESSURE TROUGH JUST WEST OF I-95
SEPARATES SOUTH VERSUS WEST WINDS. SCATTERED STORMS ARE SLOWLY
APPROACHING FROM PENNSYLVANIA. FELT THERE WAS POTENTIAL FOR
ENOUGH COVERAGE TO WARRANT A TEMPO GROUP IN THE TAFS, EVEN
THOUGH A DIRECT IMPACT IS NOT DEFINITE AT ALL TERMINAL. TIMING
WILL FAVOR 21-01Z ACROSS THE METRO TERMINALS. FARTHER SOUTH,
COVERAGE WILL BE LOWER, SO MAINTAINED PROB30 AT CHO. WINDS
SHOULD SHIFT NORTHWESTERLY BEHIND THE CONVECTION. THE PRIMARY
FRONT WILL ARRIVE LATE TONIGHT/EARLY MONDAY MORNING WITH ANOTHER
WIND SHIFT TO THE NORTH/NORTHEAST. LOWER CEILINGS ARE ALSO
FORECAST TO MOVE IN PRETTY SOON AFTER THE FRONTAL PASSAGE. MOST
GUIDANCE IS NOW FAVORING MVFR CEILINGS PERSISTING ALL DAY
MONDAY, ALTHOUGH CHO IS MORE UNCERTAIN. NORTHEASTERLY WINDS MAY
ALSO GUST 15-20 KT AT TIMES THROUGH THE DAY.
WITH THE FRONT STALLED OUT JUST TO THE SOUTH, A MOIST AIRMASS
WILL STAY IN PLACE THROUGH TUESDAY. MVFR CEILINGS LIKELY
CONTINUE, WITH SOME IFR POTENTIAL DURING THE OVERNIGHT PERIODS.
INTERMITTENT SHOWERS AND DRIZZLE COULD ALSO REDUCE VISIBILITY AT
TIMES, BUT LIKELY REMAIN WITHIN THE SAME CATEGORY AS CEILINGS
(MVFR).
SUB-VFR CONDITIONS MAY BE POSSIBLE EARLY WEDNESDAY MORNING WITHIN
ONSHORE FLOW, BUT IMPROVEMENT BACK TO VFR IS EXPECTED BY AFTERNOON.
LESSER, BUT STILL NON-ZERO CHANCES FOR LOW CLOUDS EXIST WEDNESDAY
NIGHT. VFR CONDITIONS ARE EXPECTED ON THURSDAY. WINDS WILL GENERALLY
BE OUT OF THE NORTHEAST ON WEDNESDAY AND THURSDAY, AND COULD GUST TO
AROUND 15 TO 20 KNOTS AT TIMES.
MARINE
SOUTHERLY WINDS CONTINUE UNTIL SCATTERED THUNDERSTORMS ARRIVE
THIS EVENING. WINDS ARE ALREADY 10-15 KT ALONG THE BAY, SO THERE
COULD BE A BRIEF PERIOD OF ADVISORY LEVEL CHANNELING EARLY THIS
EVENING. THE STORMS WILL BRING A POTENTIAL FOR STRONG WIND GUSTS
BEFORE DEPARTING AROUND MIDNIGHT OR SO. VARIABLE WINDS MAY THEN
PREVAIL UNTIL A COLD FRONT ARRIVES LATE TONIGHT INTO MONDAY
MORNING. NORTHEASTERLY WINDS WILL INCREASE BEHIND THE FRONT,
WITH A SMALL CRAFT ADVISORY GOING INTO EFFECT FOR ALL WATERS.
WINDS WILL DECREASE ON THE INLAND TRIBUTARIES MONDAY NIGHT BUT
LIKELY REMAIN ELEVATED ALONG THE BAY, SO THE ADVISORY CONTINUES
THERE. MARGINAL ADVISORY CONDITIONS MAY CONTINUE INTO TUESDAY
FOR PORTIONS OF THE WATERS AS WINDS TURN MORE EASTERLY. LIGHTER
EAST TO NORTHEAST WINDS CONTINUE TUESDAY NIGHT. SHOWERS AND
DRIZZLE COULD REDUCE VISIBILITY AT TIMES BOTH MONDAY AND
TUESDAY.
SCA CONDITIONS APPEAR POSSIBLE WITHIN NORTHEASTERLY FLOW WEDNESDAY
AFTERNOON THROUGH THURSDAY AS ERIN PASSES OUT TO SEA. GUSTS OF
AROUND 20 TO 25 KNOTS MAY BE POSSIBLE DURING THAT TIME.
TIDES/COASTAL FLOODING
ELEVATED TIDAL ANOMALIES PERSIST THROUGH TONIGHT. ANNAPOLIS IS
FORECAST TO REACH MINOR FLOOD AGAIN TONIGHT DURING HIGH TIDE.
WHILE OTHER LOCATIONS AREN'T CURRENTLY FORECAST TO FLOOD, SOME
COULD COME CLOSE (IE, ALEXANDRIA, HAVRE DE GRACE, SOLOMONS, AND
DAHLGREN). A PASSING COLD FRONT SHOULD REDUCE WATER LEVELS
SLIGHTLY HEADING INTO MONDAY. HOWEVER, PROLONGED ONSHORE FLOW
WILL LIKELY RESULT IN ADDITIONAL (POSSIBLY MORE WIDESPREAD) TIDAL
FLOODING LATE TUESDAY INTO WEDNESDAY.
LWX WATCHES/WARNINGS/ADVISORIES
DC...NONE.
MD...SMALL CRAFT ADVISORY FROM 6 AM MONDAY TO 2 AM EDT TUESDAY FOR
MDZ008.
COASTAL FLOOD ADVISORY FROM MIDNIGHT TONIGHT TO 5 AM EDT
MONDAY FOR MDZ014.
VA...NONE.
WV...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 6 AM MONDAY TO 2 AM EDT TUESDAY FOR
ANZ530>533-539>541.
SMALL CRAFT ADVISORY FROM NOON MONDAY TO 6 AM EDT TUESDAY FOR
ANZ534-537-543.
SMALL CRAFT ADVISORY FROM 6 AM TO 6 PM EDT MONDAY FOR ANZ535-
536-538-542.
SYNOPSIS...ADS
NEAR TERM...ADS
SHORT TERM...ADS
LONG TERM...KJP
AVIATION...ADS/KJP
MARINE...KJP
TIDES/COASTAL FLOODING...ADS
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