787
FXUS61 KLWX 231943
AFDLWX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
343 PM EDT THU APR 23 2026
WHAT HAS CHANGED
CHANCES FOR SHOWERS AND THUNDERSTORMS THIS AFTERNOON APPEAR TO
BE TRENDING DOWNWARD, BUT A FEW STILL CAN'T BE RULED OUT ACROSS
THE CENTRAL SHENANDOAH VALLEY OR CENTRAL VIRGINIA.
KEY MESSAGES
1) A FRONTAL BOUNDARY WILL LINGER NEARBY THROUGH SATURDAY,
LEADING TO CHANCES FOR SHOWERS AND THUNDERSTORMS AT TIMES.
2) HIGH PRESSURE BUILDS IN EARLY NEXT WEEK, BEFORE THE NEXT
SYSTEM APPROACHES FROM THE WEST ON TUESDAY.
DISCUSSION
KEY MESSAGE 1...A FRONTAL BOUNDARY WILL LINGER NEARBY THROUGH
SATURDAY, LEADING TO CHANCES FOR SHOWERS AND THUNDERSTORMS AT
TIMES.
CURRENT WATER VAPOR IMAGERY SHOWS POTENT UPPER LOWS OVER BOTH
THE ROCKIES AND CANADIAN MARITIMES, WITH RIDGING IN-BETWEEN
OVER THE GREAT LAKES. SKIES REMAIN MOSTLY SUNNY THIS AFTERNOON
BENEATH THAT UPPER RIDGE. TEMPERATURES HAVE CLIMBED INTO THE
UPPER 70S AND LOW 80S IN MOST LOCATIONS, AND WINDS REMAIN
RELATIVELY LIGHT. A BIT MORE CLOUD COVER IS EVIDENT ACROSS THE
CENTRAL SHENANDOAH VALLEY AND CENTRAL VIRGINIA, WHERE THERE'S
EVER SO SLIGHT SURFACE CONVERGENCE. SOME HI-RES MODELS HINT THAT
A STRAY SHOWER OR STORM MAY FORM THERE LATER THIS AFTERNOON,
BUT COVERAGE OF THESE SHOWERS AND STORMS SHOULD REMAIN LOW.
ELSEWHERE, CONDITIONS SHOULD REMAIN MOSTLY SUNNY THROUGH THE
REMAINDER OF THE AFTERNOON. DRY CONDITIONS ARE EXPECTED FOR ALL
OVERNIGHT, WITH LOWS GENERALLY IN THE 50S.
A BACKDOOR COLD FRONT WILL DROP SOUTHWESTWARD INTO THE AREA
TOMORROW, BEFORE ULTIMATELY STALLING OUT OVER THE CENTER OF THE
FORECAST AREA. MOST GUIDANCE HAS THE FRONT STALLING OUT IN THE
VICINITY OF THE POTOMAC, BUT THERE'S STILL SOME UNCERTAINTY WITH
REGARD TO ITS ULTIMATE POSITIONING. SHOWERS AND THUNDERSTORMS
WILL FORM TOMORROW AFTERNOON IN THE VICINITY OF THE FRONT. MODEL
SOUNDINGS SHOW DEEP MIXING, WITH RELATIVELY WEAK INSTABILITY
(AROUND 500 J/KG) AND MODEST AMOUNTS OF SHEAR (AROUND 30 KNOTS).
STORMS AREN'T EXPECTED TO BE SEVERE, BUT COULD PRODUCE SOME
LOCALIZED GUSTY WINDS. ANY STORMS SHOULD WIND DOWN WITH LOSS OF
DAYTIME HEATING TOMORROW EVENING. TEMPERATURES TOMORROW WILL
REACH INTO THE 80S TO THE SOUTHWEST OF THE FRONT, WITH 70S
FURTHER NORTHEAST.
HIGH PRESSURE OFF TO OUR NORTHEAST WILL STRENGTHEN ON SUNDAY
WHILE AN UPPER LEVEL DISTURBANCE SIMULTANEOUSLY TRACKS OVERHEAD.
AS THE HIGH STRENGTHENS TO OUR NORTHEAST, A STRONGER SURGE OF
EASTERLY FLOW WILL MOVE IN, CAUSING THE BACKDOOR FRONT TO PUSH
FURTHER SOUTHWEST, AND LOW CLOUDS AND COOLER AIR TO MOVE IN FROM
THE NORTHEAST. AS A RESULT, A SHARP TEMPERATURE GRADIENT MAY SET
UP ACROSS THE AREA ON SATURDAY. TEMPERATURES TO THE NORTHEAST OF
THE FRONT WILL LIKELY HOLD IN THE 50S, WHILE FURTHER SOUTHWEST
HIGHS WILL REACH INTO THE 70S. SATURDAY WILL LIKELY FEATURE ON
AND OFF SHOWERS ACROSS THE ENTIRE AREA, WITH MORE IN THE WAY OF
CLOUD COVER FURTHER TO THE NORTHEAST.
KEY MESSAGE 2...HIGH PRESSURE BUILDS IN EARLY NEXT WEEK, BEFORE
THE NEXT SYSTEM APPROACHES FROM THE WEST ON TUESDAY.
THE AFOREMENTIONED UPPER LEVEL DISTURBANCE WILL PROGRESS OFF TO
OUR EAST ON SUNDAY, CAUSING SHOWERS TO WIND DOWN FROM WEST TO
EAST DURING THE MORNING HOURS. UPPER RIDGING WILL BUILD IN ITS
WAKE, AND HOLD STRONG OVERHEAD THROUGH MUCH OF MONDAY AND
TUESDAY. HOWEVER, HIGH PRESSURE WILL REMAIN IN PLACE TO OUR
NORTHEAST. AS A RESULT, PERSISTENT ONSHORE FLOW IS EXPECTED.
THIS SHOULD LEAD TO BELOW NORMAL TEMPERATURES AND MORE IN THE
WAY OF CLOUDS THAN SUN. TEMPERATURES ON SUNDAY, MONDAY, AND
TUESDAY SHOULD REACH UP INTO THE 60S DURING THE DAY, AND THEN
DROP BACK INTO THE 40S AT NIGHT.
AN UPPER TROUGH AND ASSOCIATED SURFACE LOW WILL TRACK INTO THE
GREAT LAKES ON TUESDAY. AS OF NOW, IT LOOKS LIKE WE'LL STAY
STABLE, SO JUST SHOWERS ARE EXPECTED TUESDAY AFTERNOON INTO
TUESDAY NIGHT AS LARGE SCALE ASCENT AHEAD OF THAT SYSTEM
OVERSPREADS THE AREA.
AVIATION /18Z THURSDAY THROUGH TUESDAY/
VFR CONDITIONS ARE EXPECTED TODAY, ALONG WITH LIGHT NORTHWESTERLY
WINDS. BWI AND MTN MAY END UP WITH EAST TO SOUTHEASTERLY WINDS THIS
AFTERNOON ON THE COOL SIDE OF THE BAY BREEZE. A STRAY SHOWER OR
STORM CAN'T BE RULED OUT NEAR CHO, AND A PROB30 GROUP WAS INTRODUCED
AS A RESULT. WINDS TOMORROW WILL BE DEPENDENT ON THE POSITIONING OF
A BACKDOOR COLD FRONT, WITH LIGHT EASTERLY WINDS TO THE EAST OF THE
BOUNDARY, AND NORTHWESTERLY WINDS TO THE WEST OF THE BOUNDARY. AS OF
NOW, THE MOST LIKELY POSITION FOR THIS BOUNDARY TO STALL OUT LOOKS
TO BE IN THE VICINITY OF THE POTOMAC, SO THE WIND DIRECTION FORECAST
IS A CHALLENGING ONE, ESPECIALLY AT IAD AND DCA. SHOWERS AND
THUNDERSTORMS ARE ALSO EXPECTED TO FORM IN THE VICINITY OF THE FRONT
TOMORROW AFTERNOON, AND COULD POTENTIALLY LEAD TO TEMPORARY
RESTRICTIONS AT THE TERMINALS.
AS HIGH PRESSURE STRENGTHENS TO OUR NORTHEAST, A STRONGER PUSH OF
NORTHEASTERLY WINDS WILL ENSUE LATE FRIDAY NIGHT INTO SATURDAY. THIS
WILL PUSH THE FRONT FURTHER SOUTHWEST, AND ALLOW LOWER CEILINGS TO
START TO WORK IN FROM THE NORTHEAST. SUB-VFR CEILINGS AND SHOWERS
APPEAR LIKELY AT MOST TERMINALS ON SATURDAY, ALTHOUGH CHO MAY REMAIN
ON THE WARM SIDE OF THE BOUNDARY AND ESCAPE THE LOWER CLOUDS.
CONDITIONS SHOULD IMPROVE BACK TO VFR FOR ALL ON SUNDAY AS WINDS
TURN NORTHERLY. VFR CONDITIONS AND LIGHT EASTERLY WINDS ARE FORECAST
FOR MONDAY.
MARINE
WINDS OVER THE WATERS WILL BE CONTROLLED BY RIVER/BAY BREEZE
CIRCULATIONS TODAY, SO SUB-SCA LEVEL WINDS OF VARYING
DIRECTIONS ARE EXPECTED. WINDS TURN OUT OF THE SOUTH TONIGHT,
AND COULD NEAR LOW- END SCA LEVELS BRIEFLY WITHIN CHANNELED
SOUTHERLY FLOW. A BACKDOOR COLD FRONT WILL DROP SOUTHWESTWARD
OVER THE WATERS OVER THE COURSE OF THE DAY TOMORROW. THIS WILL
CAUSE WINDS OVER THE BAY TO TURN NORTH TO NORTHEASTERLY.
EVENTUALLY THE FRONT WILL STALL OUT OVER THE MIDDLE OF THE
FORECAST AREA. DEPENDING ON THE ULTIMATE POSITIONING OF THE
FRONT, WINDS MAY STAY NORTHWESTERLY ON THE TIDAL POTOMAC.
SHOWERS AND THUNDERSTORMS ARE EXPECTED TO DEVELOP IN THE
VICINITY OF THE FRONT TOMORROW AFTERNOON. SOME OF THE STRONGER
STORMS MAY LEAD TO SMWS BEING ISSUED FOR GUSTY WINDS.
WINDS WILL TURN EASTERLY TOMORROW NIGHT AND REMAIN EASTERLY THOUGH
THE DAY SATURDAY. WINDS MAY POTENTIALLY REACH LOW-END SCA STRENGTH
IN EASTERLY FLOW SATURDAY INTO SATURDAY NIGHT. SCA GUSTS ALSO APPEAR
POSSIBLE ON SUNDAY AS WINDS SHIFT TO OUT OF THE NORTH. SUB-SCA
EASTERLY WINDS ARE FORECAST FOR MONDAY.
LWX WATCHES/WARNINGS/ADVISORIES
DC...NONE.
MD...NONE.
VA...NONE.
WV...NONE.
MARINE...NONE.
DISCUSSION...KJP
AVIATION...KJP
MARINE...KJP
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