284
FXUS61 KLWX 221944
AFDLWX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
344 PM EDT WED JUL 22 2026
WHAT HAS CHANGED
WE CONTINUE TO MONITOR THE DEVELOPMENT OF SHOWERS AND
THUNDERSTORMS THIS AFTERNOON FROM CENTRAL VIRGINIA TO SOUTHERN
MARYLAND.
KEY MESSAGES
- 1) A FEW STRONG TO SEVERE THUNDERSTORMS ARE POSSIBLE FROM
CENTRAL VIRGINIA TO SOUTHERN MARYLAND THIS AFTERNOON.
- 2) BELOW AVERAGE TEMPERATURES AND MAINLY DRY CONDITIONS ARE
EXPECTED THURSDAY THROUGH SATURDAY.
- 3) GRADUAL INCREASE IN MOISTURE & PRECIPITATION CHANCES EARLY
NEXT WEEK.
DISCUSSION
KEY MESSAGE 1...A FEW STRONG TO SEVERE THUNDERSTORMS ARE
POSSIBLE FROM CENTRAL VIRGINIA TO SOUTHERN MARYLAND THIS
AFTERNOON.
SURFACE OBSERVATIONS AND VISIBLE SATELLITE SHOW SURFACE
CONVERGENCE BECOMING MAXIMIZED FROM CENTRAL VIRGINIA TO
SOUTHERN MARYLAND AS A COLD FRONT OVERTAKES A PRE-FRONTAL TROUGH
THAT WAS ALREADY IN PLACE. THUS FAR, SHOWERS HAVE STRUGGLED TO
MATURE, WITH VERY FEW, IF ANY, PRODUCING LIGHTNING. THIS IS
LIKELY DUE TO AMPLE DRY AIR PRESENT IN THE MID-UPPER LEVELS
EVIDENT ON BOTH THE 12Z IAD SOUNDING AND MODEL SOUNDINGS. AS
LOW-LEVEL CONVERGENCE CONTINUES TO INCREASE FROM CENTRAL
VIRGINIA TO SOUTHERN MARYLAND, IT MAY EVENTUALLY BE ENOUGH TO
OVERCOME THE DRY AIR AND SUSTAIN THE DEVELOPMENT OF THUNDERSTORMS.
IF A MORE ROBUST STORM WERE TO DEVELOP, THERE COULD BE A
CONDITIONAL THREAT FOR IT TO BECOME SEVERE, WITH DAMAGING WINDS
BEING THE PRIMARY THREAT. PARAMETER-WISE THE ENVIRONMENT IS
IMPRESSIVE, WITH AROUND 1000 J/KG OF MLCAPE, 50-60 KNOTS OF
EFFECTIVE BULK SHEAR, AND DCAPE OVER 1000 J/KG. HOWEVER, THIS
COULD BE A CASE WHERE THE HIGH DCAPE, HIGHLY SHEARED ENVIRONMENT
IS ALSO PROVING UNFAVORABLE FOR MAINTAINING DEEPER UPDRAFTS. SO
THERE'S A CONDITIONAL SEVERE THUNDERSTORM THREAT LATE THIS
AFTERNOON INTO THIS EVENING, WITH DAMAGING WINDS BEING THE
PRIMARY THREAT. SPC HAS FAR SOUTHERN MARYLAND OUTLOOKED IN A
SLIGHT (LEVEL 2 OF 5) RISK FOR SEVERE THUNDERSTORMS, WITH A
MARGINAL (LEVEL 1 OF 5) RISK EXTENDING A BIT FURTHER NORTH AND
WEST. ANY SHOWERS OR STORMS SHOULD GRADUALLY WIND DOWN THROUGH
THE EVENING, WITH DRIER CONDITIONS EXPECTED DURING THE SECOND
HALF OF THE NIGHT. COOLER, DRIER AIR WILL START TO FILTER IN
BEHIND THE FRONT, WITH OVERNIGHT LOWS DROPPING BACK INTO THE 50S
TO THE WEST OF THE BLUE RIDGE, WITH LOW-MID 60S FURTHER EAST.
KEY MESSAGE 2...BELOW AVERAGE TEMPERATURES AND MAINLY DRY
CONDITIONS ARE EXPECTED THURSDAY THROUGH SATURDAY.
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. SOME MOISTURE COULD BE DRAWN NORTHWARD
FROM THE STALLED FRONTAL ZONE ACROSS THE SOUTHEASTERN STATES
DURING THIS TIME. THE CURRENT FORECAST HAS SOME LOW RAIN CHANCES
BOTH DAYS, MAINLY IN SOUTHERN PORTIONS OF THE CWA AND ALONG THE
ALLEGHENY MOUNTAINS.
KEY MESSAGE 3... GRADUAL INCREASE IN MOISTURE & PRECIPITATION
CHANCES EARLY NEXT WEEK.
BROAD HIGH PRESSURE WILL CONTINUE TO SHIFT NORTHEAST OVER THE
WEEKEND, WITH LOW PRESSURE BUILDING OVER NORTHEASTERN CANADA
AND A STEMMING TROUGH POTENTIALLY FORMING OVER THE MID-ATLANTIC LATE
SUNDAY AND INTO MONDAY. DEWPOINTS START TO INCREASE DURING THIS
TIME, SO SHOWER & THUNDERSTORM CHANCES COULD INCREASE DURING THE
AFTERNOON & EVENING HOURS SUNDAY AND MONDAY AS THIS PERTURBATION
MOVES THROUGH. MACHINE-LEARNING ALGORITHMS SHOW SOME LOWER-END
PROBABILITIES FOR SEVERE OCCURRENCE DURING THIS TIME, ALTHOUGH
ENSEMBLES STILL SHOW UNCERTAINTY IN TIMING OF THE OVERALL SYNOPTIC
SETUP. AS THIS TROUGH APPROACHES, TEMPERATURES GRADUALLY BEGIN TO
INCREASE BACK INTO THE UPPER 80S.
DEWPOINTS COULD REMAIN ELEVATED WITHIN THE REGION AS THIS SYSTEM
MOVES THROUGH, WITH THE UPPER-LEVEL LOW TO THE NORTH SLOWLY
TRACKING TO THE SOUTH BEFORE SHIFTING TO THE NORTHEAST MIDWEEK. THIS
COULD OVERALL RE-INTRODUCE CHANCES FOR RAIN WITHIN THE REGION
AFTER A BRIEF DRY SPELL.
AVIATION /18Z WEDNESDAY THROUGH MONDAY/
PREVAILING VFR CONDITIONS ARE EXPECTED AT THE TERMINALS TODAY.
WE CONTINUE TO MONITOR THE DEVELOPMENT OF SHOWERS AND
THUNDERSTORMS ESPECIALLY TO THE SOUTH OF DCA. PROB30S HAVE BEEN
MAINTAINED IN THE TAF FOR BOTH DCA AND CHO, BUT COVERAGE OF
STORMS APPEARS TO BE LESSER THAN HAS BEEN ADVERTISED BY MOST
GUIDANCE THUS FAR. ANY THREAT FOR SHOWERS AND STORMS SHOULD
GRADUALLY WIND DOWN THIS EVENING. THEREAFTER, PREDOMINANTLY VFR
CONDITIONS ARE EXPECTED AT THE TERMINALS THROUGH SATURDAY. LOWER
CEILINGS COULD BRIEFLY BE POSSIBLE IN EASTERLY FLOW ON FRIDAY OR
SATURDAY. WINDS WILL PREDOMINANTLY BE OUT OF THE WEST TO
NORTHWEST TODAY, NORTH LATER TONIGHT INTO TOMORROW, AND THEN
EAST TO SOUTHEAST ON FRIDAY AND SATURDAY.
PREDOMINANTLY VFR CONDITIONS ARE ANTICIPATED ACROSS TERMINALS SUNDAY
AND MONDAY, ALTHOUGH A FEW SCATTERED SHOWERS AND THUNDERSTORMS IN
THE AFTERNOON/EVENING HOURS COULD TEMPORARILY CAUSE REDUCED
CONDITIONS DURING THIS PERIOD. LIGHT SOUTHEASTERLY WINDS BRIEFLY
SHIFT SOUTHWESTERLY BY MONDAY EVENING.
MARINE
SMALL CRAFT ADVISORY CONDITIONS ARE ONGOING AT MOST LOCATIONS
THIS AFTERNOON WITHIN WESTERLY FLOW. SMWS MAY ALSO POTENTIALLY
BE NEEDED THIS AFTERNOON AS SHOWERS AND THUNDERSTORMS MOVE OVER
THE WATERS. WINDS SHIFT TO OUT OF THE NORTH TONIGHT, WITH SCAS
IN EFFECT WITHIN CHANNELED NORTHERLY FLOW FOR THE MAIN STEM OF
THE BAY AND THE LOWER TIDAL POTOMAC. NORTHERLY WINDS GRADUALLY
DECREASE THROUGH THE DAY TOMORROW, BEFORE TURNING OUT OF THE
EAST TO SOUTHEAST FOR FRIDAY AND SATURDAY.
WINDS REMAIN BELOW SCA THRESHOLDS THROUGH SUNDAY AND MONDAY, WITH
SOUTHEAST WINDS SHIFTING SOUTHWESTERLY BY MONDAY EVENING. SCATTERED
SHOWERS & THUNDERSTORMS COULD BRING SOME GUSTIER WINDS OVER THE
WATERS IN THE AFTERNOON & EVENING HOURS DURING THIS PERIOD.
TIDES/COASTAL FLOODING
WATER LEVELS ARE EXPECTED TO DECREASE WITHIN NORTH TO
NORTHWESTERLY FLOW BEHIND A COLD FRONT. ANOMALIES GRADUALLY
REBOUND WITHIN EASTERLY FLOW THIS WEEKEND, WITH MORE SENSITIVE
LOCATIONS POTENTIALLY REACHING ACTION STAGE.
LWX WATCHES/WARNINGS/ADVISORIES
DC...NONE.
MD...SMALL CRAFT ADVISORY FROM 9 PM THIS EVENING TO 8 AM EDT
THURSDAY FOR MDZ008.
VA...NONE.
WV...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 9 PM THIS EVENING TO 8 AM EDT
THURSDAY FOR ANZ530>532-539-540.
SMALL CRAFT ADVISORY FROM MIDNIGHT TONIGHT TO 11 AM EDT
THURSDAY FOR ANZ533-534-537-541-543.
SMALL CRAFT ADVISORY UNTIL 6 PM EDT THIS EVENING FOR ANZ534-
537-543.
DISCUSSION...KJP/SRT/ADS
AVIATION...KJP/SRT
MARINE...KJP/SRT
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