479
FXUS61 KLWX 220145
AFDLWX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
945 PM EDT TUE JUL 21 2026
WHAT HAS CHANGED
HAVE DROPPED THE FLOOD WATCHES GIVEN LOWERING COVERAGE AND
INCREASINGLY PROGRESSIVE MOTION OF HEAVY RAIN. EXTENDED THE
SEVERE THUNDERSTORM WATCH GIVEN (1) SUPERCELL IN SOUTHEAST WV,
AND (2) COMPLEX OF ORGANIZING THUNDERSTORMS APPROACHING SOUTHERN
MARYLAND AND VICINITY.
KEY MESSAGES
- SEVERE WEATHER RISK WILL CONTINUE THROUGH THIS EVENING WITH
THE GREATEST RISK ACROSS CENTRAL VA, SOUTHERN MD, AND THE
APPALACHIAN REGION.
- BELOW AVERAGE TEMPERATURES AND MAINLY DRY CONDITIONS
ARE EXPECTED THURSDAY THROUGH THE WEEKEND.
DISCUSSION
KEY MESSAGE 1...SEVERE WEATHER RISK WILL CONTINUE THROUGH THIS EVENING WITH
THE GREATEST RISK ACROSS CENTRAL VA, SOUTHERN MD, AND THE APPALACHIAN
REGION.
WIDESPREAD SHOWERS AND THUNDERSTORMS CONTINUE THIS EVENING. THE
MAIN NEAR-SURFACE-BASED INSTABILITY IS NEAR AND SOUTH OF US-50.
AN MCV FROM EARLIER CONVECTION CROSSING PAGE COUNTY VA IS LIKELY
ADVECTING A NARROW PLUME OF SBCAPE AROUND ITS EASTERN PERIPHERY,
WHICH WILL CONTINUE TO SUPPORT A GUSTY WIND RISK EAST OVER THE
NEXT COUPLE HOURS AS IT APPROACHES NEAR/SOUTH OF THE IMMEDIATE
DC METRO AREA. TO THE NORTH, WARM/MOIST ADVECTION DUE TO AN
INCREASING LLJ WILL CONTINUE BETWEEN I-66 AND I-70, FOCUSING
HEAVY THUNDERSTORMS IN THESE AREAS.
THANKS TO ONGOING DROUGHT, MOST FLOODING TO THIS POINT HAS BEEN
ISOLATED. STILL, URBAN AREAS OR AREAS THAT HAVE ALREADY RECEIVED
SUBSTANTIAL RAIN RECENTLY WILL CONTINUE TO BE AT RISK OF
FLOODING UNTIL LATE EVENING.
STILL A RISK OF SEVERE WX WED, BUT LIKELY FOR AREAS SOUTH OF THE
CAPITAL BELTWAY AND SOUTHERN MD.
KEY MESSAGE 2...BELOW AVERAGE TEMPERATURES AND MAINLY DRY CONDITIONS
ARE EXPECTED THURSDAY THROUGH THE WEEKEND.
KEY MESSAGE 2 DESCRIPTION...
A SPRAWLING AREA OF HIGH PRESSURE WILL BUILD TO OUR NORTH FOR
THURSDAY AND FRIDAY, BEFORE SHIFTING OFF THE NEW ENGLAND COASTLINE
ON SATURDAY. NORTHERLY FLOW AHEAD OF THE APPROACHING HIGH WILL
ADVECT A MUCH COOLER AND DRIER AIRMASS INTO THE REGION FOR THURSDAY.
WELL BELOW NORMAL TEMPERATURES AND DEWPOINTS ARE FORECAST FOR LATE
JULY, WITH HIGH TEMPERATURES ONLY IN THE UPPER 70S/LOW 80S. DEWPOINTS
IN THE 50S WILL ALSO MAKE IT FEEL MUCH LESS HUMID THAN IS TYPICAL
FOR JULY. MOSTLY SUNNY SKIES WILL ACCOMPANY THE WELL BELOW NORMAL
TEMPERATURES/DEWPOINTS. TEMPERATURES WILL STAY WELL BELOW NORMAL FOR
FRIDAY AND SATURDAY WITHIN EASTERLY FLOW. BOTH TEMPERATURES AND
DEWPOINTS BEGIN TO RISE AGAIN ON SUNDAY AS FLOW TURNS SOUTHERLY,
WITH HIGHS IN THE MID TO UPPER 80S AND DEWPOINTS IN THE 60S. THE
RETURN OF HIGHER DEWPOINT AIR SHOULD LEAD TO SLIGHTLY GREATER
CHANCES FOR AFTERNOON/EVENING SHOWERS AND THUNDERSTORMS, BUT MOST
LOCATIONS WILL LIKELY STILL STAY DRY.
FORECAST CONFIDENCE DECREASES SUBSTANTIALLY BY MONDAY AND TUESDAY,
BUT CHANCES FOR SHOWERS AND THUNDERSTORMS MAY FURTHER INCREASE AS
MULTIPLE SHORTWAVE DISTURBANCES MOVE THROUGH IN NORTHWESTERLY FLOW
ALOFT. DEPENDING ON HOW THE FORECAST DETAILS EVOLVE, THERE COULD BE
A CONDITIONAL THREAT FOR SEVERE THUNDERSTORMS ON EITHER MONDAY OR
TUESDAY.
AVIATION /01Z WEDNESDAY THROUGH SUNDAY/
WIDESPREAD SHOWERS AND THUNDERSTORMS EXPECTED THROUGH MID
EVENING WITH THE RISK OF SOME SEVERE WX. THUNDERSTORM RISK WED
WILL LIKELY STAY SOUTH OF THE MAIN TERMINALS.
PREVAILING VFR CONDTIONS ARE EXPECTED THURSDAY THROUGH SATURDAY.
WINDS WILL GENERALLY BE OUT OF THE NORTH ON THURSDAY, EAST ON
FRIDAY, AND EAST TO SOUTHEAST ON SUNDAY.
MARINE
NUMEROUS TO WIDESPREAD SHOWERS AND THUNDERSTORMS EXPECTED, SOME
OF WHICH MAY REQUIRE SMWS THIS AFTERNOON AND THIS EVENING AND
AGAIN WEDNESDAY.
SCA CONDITIONS MAY LINGER IN NORTHERLY FLOW INTO THURSDAY MORNING.
THEREAFTER, SUB-SCA LEVEL WINDS ARE EXPECTED THURSDAY AFTERNOON
THROUGH SATURDAY. WINDS WILL GENERALLY BE OUT OF THE NORTH ON
THURSDAY, EAST ON FRIDAY, AND EAST TO SOUTHEAST ON SATURDAY.
TIDES/COASTAL FLOODING
ELEVATED SOUTHERLY FLOW CONTINUES THROUGH THIS EVENING, PUSHING
ANOMALIES CLOSE TO ONE FOOT. NO TIDAL FLOODING IS FORECAST AT
THIS TIME, BUT ANNAPOLIS AND HAVRE DE GRACE WILL BE CLOSE. WATER
LEVELS WILL DROP AS A COLD FRONT PASSES WEDNESDAY.
LWX WATCHES/WARNINGS/ADVISORIES
DC...NONE.
MD...SMALL CRAFT ADVISORY UNTIL 8 AM EDT WEDNESDAY FOR MDZ008.
VA...NONE.
WV...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 8 AM EDT WEDNESDAY FOR ANZ530-531-
538-539.
SMALL CRAFT ADVISORY UNTIL NOON EDT WEDNESDAY FOR ANZ532-533-
540>542.
SMALL CRAFT ADVISORY UNTIL 6 PM EDT WEDNESDAY FOR ANZ534-537-
543.
SMALL CRAFT ADVISORY UNTIL 4 AM EDT WEDNESDAY FOR ANZ535-536.
DISCUSSION...ADS/LFR/DHOF
AVIATION...ADS/LFR/DHOF
MARINE...ADS/LFR/DHOF
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