752
FXUS61 KLWX 261825
AFDLWX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
225 PM EDT TUE MAY 26 2026
WHAT HAS CHANGED
ISSUED A FLOOD WATCH FOR PARTS OF THE NORTHERN ALLEGHENIES
TONIGHT INTO WEDNESDAY. SPC ADDED A SLIGHT RISK (LEVEL 2 OUT OF
5) FOR SEVERE WEATHER ON WEDNESDAY.
KEY MESSAGES
- 1) LOCALIZED FLOOD THREAT TODAY, WITH FLOOD AND SEVERE
THUNDERSTORM THREATS AREAWIDE WEDNESDAY.
- 2) HIGH PRESSURE MOVES INTO THE REGION FRIDAY, WITH
TEMPERATURES REMAINING SEASONABLE INTO NEXT WEEK.
DISCUSSION
KEY MESSAGE 1...LOCALIZED FLOOD THREAT TODAY, WITH FLOOD AND SEVERE
THUNDERSTORM THREATS AREAWIDE WEDNESDAY.
STALLED FRONTAL BOUNDARY REMAINS THE FOCUS FOR SHOWERS AND
STORMS TODAY. DEEP SOUTHERLY FLOW ON THE WESTERN PERIPHERY OF
THE BERMUDA HIGH CONTINUES TO ADVECT DEEP TROPICAL MOISTURE INTO
OUR AREA. EXPECTING ANOTHER ROUND OF DIURNALLY DRIVEN SHOWERS
AND THUNDERSTORMS THIS AFTERNOON/EVENING. LIGHT SOUTHEAST FLOW
DEVELOPS TODAY, WHICH WILL FAVOR SHOWERS AND THUNDERSTORMS WEST
OF THE BLUE RIDGE AND IN CENTRAL VA.
STORM MOTION IS GOING TO BE SLOW AND ERRATIC DUE TO WEAK LOW-LEVEL
FLOW. VERY HIGH PWATS AROUND 1.9" AND A DEEP WARM CLOUD LAYER COULD
YIELD RAINFALL RATES IN EXCESS OF 1-2"/HR IN THE STRONGEST STORMS.
THIS COULD RESULT IN A FLOOD THREAT, ESPECIALLY IF THUNDERSTORMS
BECOME LOCKED TO THE TERRAIN (WHICH COULD YIELD ARE HIGHER FLOOD
THREAT FOR THAT LOCAL AREA). THE RRFS AND HRRR INDICATE THIS IS A
POSSIBILITY. WPC HAS A MARGINAL RISK (LEVEL 1 OF 4) FOR FLASH
FLOODING IN THESE AREAS, AND THAT ALIGNS WELL WITH THE CURRENT
THINKING OF HOW MANY HEAVY THUNDERSTORMS WILL DEVELOP. ONE OF THE
UNDERLYING UNCERTAINTIES IS GOING TO BE WHERE THESE STORMS
DEVELOP.
COME TONIGHT, MODELS SUPPORT A GREATER COVERAGE OF STORMS ALONG
THE FRONT ARCING INTO OUR NW ALLEGHENY ZONES. HAVE ISSUES A
FLOOD WATCH IN COORDINATION WITH PBZ/RLX/CTP. THE LOCAL
STREAMS/CREEKS ARE RUNNING RATHER HIGH UP THERE, AND AN
ADDITIONAL 1-3" OF RAIN COULD PUT THE STREAMS/CREEKS AT BANKFULL.
WILL CONTINUE TO MONITOR POTENTIAL EASTERN EXPANSION, BUT FEEL
GOOD WITH WHERE THE WATCH IS FOR NOW.
BY WED THE UPPER TROUGHING TO THE NORTH BEGINS TO SLIDE SOUTH,
WITH AN ACCOMPANYING COLD FRONT ALSO PUSHING SOUTH THROUGH THE
MID- ATLANTIC. THE PRESENCE OF GROWING INSTABILITY, LINGERING
DEEP LAYER MOISTURE, AND MUCH MORE FORCING/SHEAR FROM THE UPPER
TROUGH IS GOING TO INTRODUCE A SEVERE WEATHER THREAT FOR MOST OF
THE AREA. SPC HAS ADDED A SLIGHT RISK (LEVEL 2 OUT OF 5) FOR
SOUTH OF THE POTOMAC RIVER INCLUDING DC AND SOUTHERN MD.
ELSEWHERE, A MARGINAL RISK REMAINS IN EFFECT. COVERAGE OF
THUNDERSTORMS IS STILL UNCERTAIN, BUT IT WILL CERTAINLY BE MORE
THAN TODAY. MAIN THREAT APPEARS TO BE STRONG WINDS GIVEN STEEP
LOW-LEVEL LAPSE RATES. STORM MOTION IS GOING TO BE FASTER AS
DEEP-LAYER WINDS INCREASE, BUT LOCALLY HEAVY RAINFALL COULD
PRODUCE SOME FLOOD THREAT, ESPECIALLY IN URBAN AREAS. ONE
CONCERN IS THE DEEP WESTERLY FLOW, WHICH HISTORICALLY CAUSES
ISSUES FOR STORMS TO FORM IN OUR AREA AT TIMES.
KEY MESSAGE 2...HIGH PRESSURE MOVES INTO THE REGION FRIDAY,
WITH TEMPERATURES REMAINING SEASONABLE INTO NEXT WEEK.
SKIES TREND CLEARER BEGINNING THU AND GOING INTO FRI AS A SFC
HIGH TRANSITIONS INTO THE REGION, ALONG WITH SIGNIFICANT DRY
AIR COMING IN FROM THE NORTH. DESPITE AN ULL SWINGING DOWN INTO
THE NORTHEAST THAT COULD BRING A VERY SLIGHT CHANCE FOR SHOWERS
TO FORM HERE ALONG THE SOUTHERN EDGE OF THE REGION, PERSISTENT
HIGH PRESSURE OFF TO THE WEST WILL QUICKLY TRANSITION THE LOW
OFFSHORE AND MINIMIZE PRECIP CHANCES IN THE AREA. THIS PATTERN
SIGNAL HAS STAYED CONSISTENT OVER SEVERAL MODEL RUNS NOW, BUT
IT'S STILL WORTH NOTING THAT ANY SOUTHWARD SHIFT IN TRACK FROM
THIS LOW WOULD INCREASE ANY CHANCE FOR SHOWERS OVER THE WEEKEND.
FOR NOW, IT LOOKS LIKE ONLY A SLIGHT UPTICK IN CLOUD COVER WILL
RESULT FROM THIS WHILE THE STEMMING COLD FRONT KEEPS TEMPS
MODERATE THROUGH THE END OF THE FORECAST PERIOD. HIGHS
CONSISTENTLY RANGE IN THE 70S FOR MOST AREAS THROUGH MON, WITH
LOWS GENERALLY RANGING IN THE 50S OVERNIGHT BETWEEN FRI AND MON.
CONDITIONS REMAIN CLEAR GOING INTO NEXT WEEK ON MON, WITH
UPPER-LEVEL RIDGING PERSISTING.
AVIATION /18Z TUESDAY THROUGH SUNDAY/
THE STALLED BOUNDARY OVER THE AREA WILL CONTINUE SUB-MVFR
CONDITIONS INTO THIS EVENING, BUT IMPROVEMENTS TO VFR ARE
LIKELY FOR SEVERAL HOURS. CIGS DROP AGAIN TONIGHT TO IFR TO LIFR
LEVELS. RESTRICTIONS PERSIST INTO WED. AFTERNOON TO EVENING
THUNDERSTORMS ARE LIKELY TO MOVE ACROSS THE AREA, AND THIS COULD
LEAD TO BRIEF REDUCTIONS AND GUSTY WINDS AT ALL TERMINALS. A
COLD FRONT SWEEPS THROUGH WED NIGHT, WITH DRY AND VFR
CONDITIONS RETURNING FOR THU.
VFR CONDITIONS ARE EXPECTED FRI AND SAT. LIGHT NW WINDS COULD
TEMPORARILY FLOW W BETWEEN FRI AND SAT BEFORE RETURNING TO NW
FLOW.
MARINE
LIGHT SOUTHEAST WINDS DEVELOP THIS AFTERNOON, THEN BECOME VARIABLE
TONIGHT INTO WED. THUNDERSTORMS ARE POSSIBLE ACROSS THE WATERS
WED AFTERNOON, AND SMWS MAY BE NEEDED. SCA CONDITIONS ARE
POSSIBLE THU INTO THU NIGHT.
WIND GUSTS PREDOMINANTLY STAY BELOW SCA CRITERIA FRI, BUT COULD
BRIEFLY APPROACH LOW-END SCA CRITERIA IN THE SOUTHERN PORTIONS
OF THE CHESAPEAKE BAY IN THE MORNING. WINDS START TO INCREASE
OVER THE WATERS LATE SAT AFTERNOON AND EVENING, WITH SCAS
BECOMING A POSSIBILITY OVER THE SOUTHERN BAY DURING THEN.
NW WINDS BRIEFLY TREND S'LY ON FRI NIGHT BEFORE FLOWING
N'LY AGAIN BY SAT EVENING.
LWX WATCHES/WARNINGS/ADVISORIES
DC...NONE.
MD...FLOOD WATCH FROM LATE TONIGHT THROUGH WEDNESDAY AFTERNOON FOR
MDZ501-509-510.
VA...NONE.
WV...FLOOD WATCH FROM LATE TONIGHT THROUGH WEDNESDAY AFTERNOON FOR
WVZ501-503-505.
MARINE...NONE.
DISCUSSION...KRR/CPB
AVIATION...KRR/CPB
MARINE...KRR/CPB
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