485
FXUS61 KLWX 231445
AFDLWX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
1045 AM EDT SUN AUG 23 2026
WHAT HAS CHANGED
ADDED IN A SLIGHT CHANCE FOR A SHOWER OR THUNDERSTORM TO THE
EAST OF THE BLUE RIDGE THIS AFTERNOON INTO THIS EVENING.
KEY MESSAGES
- 1) SLIGHT CHANCE FOR A SHOWER OR STORM THIS AFTERNOON, THEN
DRY CONDITIONS ANTICIPATED THROUGH EARLY PORTIONS OF THE WEEK.
- 2) WARMER AND MORE HUMID CONDITIONS RETURN MID-WEEK,
WITH THUNDERSTORM CHANCES RETURNING BY THURSDAY.
DISCUSSION
KEY MESSAGE 1...SLIGHT CHANCE FOR A SHOWER OR STORM THIS AFTERNOON,
THEN DRY CONDITIONS ANTICIPATED THROUGH EARLY PORTIONS OF THE
WEEK.
CURRENT WATER VAPOR IMAGERY SHOWS A DEEP UPPER LOW IN PLACE OVER
THE GREAT LAKES, WITH BROAD TROUGHING EXTENDING FURTHER OUT
ALONG THE EAST COAST. LOCALLY, WE ARE SITUATED JUST DOWNSTREAM
OF THE PRIMARY TROUGH AXIS. DRIER AIR SHOULD CONTINUE TO ADVECT
IN AT LOW-LEVELS WITHIN WESTERLY FLOW OVER THE COURSE OF THE
DAY, BUT SOME WEAK INSTABILITY (AROUND 500-1000 J/KG OF MLCAPE)
MAY DEVELOP BY PEAK HEATING. FORECAST SOUNDINGS SHOW VERY DRY
AIR IN PLACE AT MID-LEVELS ALONG WITH A WEAKNESS/SLIGHTLY WARMER
LAYER LIKELY TIED TO LARGE SCALE SUBSIDENCE. CAMS SUGGEST THAT
A FEW SHOWERS OR EVEN A THUNDERSTORM OR TWO MAY POTENTIALLY FORM
LATER THIS AFTERNOON, ESPECIALLY TO THE EAST OF THE BLUE RIDGE
AS THE UPPER TROUGH AXIS MOVES THROUGH. HOWEVER, MOST LOCATIONS
ARE EXPECTED TO REMAIN DRY. WHILE CONDITIONS OVERALL APPEAR
RELATIVELY HOSTILE TOWARD DEEPER CONVECTION DEVELOPING, IF A
DEEPER STORM WERE TO DEVELOP, THERE COULD BE A CONDITIONAL
THREAT FOR SOME SMALL HAIL, GIVEN COOLER, DRIER THERMAL
PROFILES, MINIMAL CAPE BELOW THE FREEZING LEVEL, AND STRAIGHT
LINE HODOGRAPHS WITH VERY LITTLE LOW-LEVEL SHEAR, BUT
RESPECTABLE SHEAR (AROUND 35-40 KTS 0-6 KM) THROUGH THE MID-
UPPER LEVELS. ANY SHOWERS OR STORMS SHOULD QUICKLY DISSIPATE
WITH LOSS OF DAYTIME HEATING THIS EVENING.
ON MONDAY, WE ARE EXPECTING A COLD FRONT TO PASS THROUGH OUR REGION.
BEHIND THE FRONT, NORTHWESTERLY WINDS USHER IN DRY AIR FROM CENTRAL
CANADA. THESE SUB-60F DEWPOINTS COULD PERSIST UNTIL MIDWEEK. WITH
HIGH PRESSURE BUILDING OVER THE APPALACHIAN MOUNTAINS, DRIER AND
COOLER CONDITIONS COULD LAST UNTIL LATE TUESDAY.
OVERALL, WE ARE EXPECTING HIGHS TO REMAIN IN THE 70S AND MID
80S EARLY THIS WEEK. OVERNIGHT LOWS RANGING IN THE 50S AND 60S
THROUGHOUT THE REGION.
KEY MESSAGE 2...WARMER AND MORE HUMID CONDITIONS RETURN MID-
WEEK, WITH THUNDERSTORM CHANCES RETURNING BY THURSDAY.
BEGINNING WEDNESDAY, A WARM TROPICAL AIR MASS TRACKS NORTHEAST OVER
THE MID-ATLANTIC, BRINGING HUMIDITY BACK TO SUMMERTIME NORMALS AS
WELL AS A GRADUAL INCREASE IN TEMPERATURES. A SHORTWAVE UPPER-LEVEL
TROUGH WILL BEGIN TO FORM OVER THE GREAT LAKES REGION AND TRACK
EASTWARD TOWARDS THE COAST BETWEEN WEDNESDAY AND THURSDAY, AND THIS
COMBINED WITH THE INCREASE IN HEAT & HUMIDITY WILL CREATE ADDITIONAL
CHANCES FOR RAIN & THUNDERSTORM DEVELOPMENT ACROSS THE REGION. MODEL
GUIDANCE CONTINUES TO SHOW ONLY MARGINAL CHANCES REGARDING ANY OF
THESE THUNDERSTORMS BECOMING SEVERE, WITH SOME UNCERTAINTY REMAINING
IN THE OVERALL TRACK OF THIS SYSTEM. CURRENT GUIDANCE SUGGESTS THAT
THIS SYSTEM COULD BE SLOW-MOVING ACROSS THE REGION, WITH RAIN
CHANCES POTENTIALLY EXTENDING INTO THE END OF THE WEEK AS THIS
SYSTEM SLOWLY TRACKS OFFSHORE. OVERALL, EXPECT INCREASING HUMIDITY
ALONG WITH A FEW CHANCES FOR RAIN LATE NEXT WEEK AS THIS SYSTEM
SLOWLY TRACKS TOWARDS THE COAST. UPPER-LEVEL ZONAL FLOW TAKES OVER
AS THIS TROUGH TRACKS EAST.
AVIATION /14Z SUNDAY THROUGH THURSDAY/
PREDOMINANTLY VFR CONDITIONS ARE ANTICIPATED ACROSS TERMINALS
THROUGH WEDNESDAY. THERE IS A VERY, VERY SMALL CHANCE FOR A
PASSING SHOWER OR STORMS AT IAD, DCA, BWI, OR MTN THIS
AFTERNOON, BUT CHANCES ARE TOO LOW TO DIRECTLY MENTION IN THE
TAFS AT THIS TIME. WINDS TODAY THROUGH TUESDAY REMAIN OUT OF
THE WNW TO NW, GUSTING UP TO 20 KNOTS DURING THE AFTERNOON HOURS
(EXCEPT CHO WHICH WILL BE 5 TO 8 KNOTS LOWER).
PERIODIC SHOWERS & THUNDERSTORMS COULD CREATE TEMPORARILY REDUCED
CONDITIONS AT TERMINALS DURING THE AFTERNOON & EVENING HOURS
WEDNESDAY AND THURSDAY. NORTHWEST WINDS SHIFT SOUTHEASTERLY BY
WEDNESDAY NIGHT.
MARINE
WINDS TURN OUT OF THE WNW TO NW THROUGH TUESDAY, AND SHOULD
REMAIN SUB-SCA THROUGHOUT THAT PERIOD FOR THE MOST PART. A FEW
GUSTS NEAR 18 KNOTS ARE POSSIBLE, ESPECIALLY FURTHER NORTH AND
DURING THE AFTERNOON HOURS, BUT NOT SEEING A PROLONGED PERIOD
ENOUGH TO WARRANT AN SCA AT THIS TIME.
WINDS SHIFT SOUTHERLY BY WEDNESDAY, WITH WINDS GUSTING ABOVE
SCA THRESHOLDS LATER THAT EVENING IN A CLASSIC SOUTHERLY
CHANNELING EVENT AHEAD OF AN APPROACHING COLD FRONT.
WINDS COULD REACH MARGINAL SCA CONDITIONS AGAIN THURSDAY
EVENING AS A COLD FRONT PASSES THROUGH THE REGION. SCATTERED
SHOWERS & THUNDERSTORMS IN THIS TIMEFRAME COULD ALSO CREATE
LOCALLY GUSTY WINDS OVER THE WATERS, PERHAPS NECESSITATING
SMWS.
TIDES/COASTAL FLOODING
TIDAL ANOMALIES ARE EXPECTED TO DECREASE OVER THE COURSE OF THE
DAY TODAY AS WINDS TURN OUT OF THE WEST. ANNAPOLIS MAY REACH
ACTION STAGE AROUND HIGH TIDE, BUT NO TIDAL FLOODING IS
ANTICIPATED.
LWX WATCHES/WARNINGS/ADVISORIES
DC...NONE.
MD...NONE.
VA...NONE.
WV...NONE.
MARINE...NONE.
DISCUSSION...CJL/KJP/SRT
AVIATION...CJL/KJP/SRT
MARINE...CJL/SRT
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