950
FXUS61 KLWX 030100
AFDLWX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
900 PM EDT SUN AUG 2 2026
WHAT HAS CHANGED
A FLOOD WATCH WAS ISSUED FOR THE BALTIMORE/WASHINGTON METRO
EARLIER UNTIL MIDNIGHT, BUT THIS MAY BE A CANDIDATE FOR
CANCELLATION IF ADDITIONAL STORMS CONTINUE TO FOCUS WEST OF THE
WATCH AREA. STILL WATCHING POTENTIAL CONVECTION CROSS THE
MOUNTAINS AS WELL, BUT IT IS BECOMING INCREASINGLY UNCERTAIN
WHETHER ANY IS STRONG ENOUGH TO PRODUCE FLASH FLOODING. A
COASTAL FLOOD ADVISORY WAS ALSO ISSUED FOR ANNE ARUNDEL COUNTY.
KEY MESSAGES
- 1) REPETITIVE ROUNDS OF LOCALLY HEAVY SHOWERS AND
THUNDERSTORMS COULD LEAD TO INSTANCES OF FLASH FLOODING
THROUGH MONDAY.
- 2) ADDITIONAL SHOWER AND THUNDERSTORM CHANCES TUESDAY INTO THE
UPCOMING WEEKEND AHEAD.
DISCUSSION
KEY MESSAGE 1...REPETITIVE ROUNDS OF LOCALLY HEAVY SHOWERS AND
THUNDERSTORMS COULD LEAD TO INSTANCES OF FLASH FLOODING THROUGH
MONDAY.
CONVECTION HAS BEEN FOCUSING IN TWO CORRIDORS. THE FIRST EAST OF
THE BLUE RIDGE IN AN AXIS OF HIGH PRECIPITABLE WATER VALUES
WHICH WARRANTED THE EARLIER EXTENSION OF THE FLOOD WATCH TO THE
BALTIMORE WASHINGTON METRO AREA. THE SECOND CORRIDOR HAS BEEN
WEST OF THE FORECAST AREA, CLOSER TO THE SURFACE LOW/FRONT AND
UPPER TROUGH. THIS HAS LEFT AREAS BETWEEN THE BLUE RIDGE AND
ALLEGHENIES GENERALLY DRY. RECENT MODELS STILL HAVE AT LEAST
SOME CONVECTION TRANSITIONING EASTWARD OVER THE NEXT SEVERAL
HOURS, BUT IF RADAR TRENDS KEEP WEAKENING, THE FLOOD WATCH MAY
BE CANCELLED. MEANWHILE, SCATTERED STORMS EXTEND SOUTHWESTWARD
INTO NC, SO IT'S POSSIBLE THESE INTERMITTENT DOWNPOURS COULD
CONTINUE EAST OF THE BLUE RIDGE WELL INTO THE NIGHT. IT DOES
APPEAR THERE SHOULD BE A DRYING TREND TOWARD DAWN HOWEVER.
THE HODOGRAPH ON THE 00Z IAD SOUNDING SHOWS 150 M2/S2 OF 0-1KM
HELICITY, AND STRONGER CELLS WHICH CAN FEEL THE DEEP LAYER SHEAR
CONTINUE TO SHOW TRANSIENT ROTATION. AT THIS POINT IN THE
EVENING, THE LOW LEVELS ARE LIKELY BECOMING INCREASINGLY STABLE,
SO THE THREAT OF ANY TORNADOES OR DAMAGING WINDS APPEARS TO BE
DECREASING.
THUNDERSTORMS CONTINUE TO CARRY A RISK FOR HEAVY RAINFALL GIVEN
PRECIPITABLE WATER (PWAT) VALUES RANGING FROM 2 TO 2.4 INCHES
(THE 00Z IAD SOUNDING MAY BE A RECORD FOR THE DAY). SITTING
NEAR RECORD NUMBERS CERTAINLY SUPPORTS THE TORRENTIAL DOWNPOUR
POTENTIAL. AFTER THESE STORMS TAPER OFF, LOWS WILL BE IN THE
MID 60S TO LOW 70S. DESPITE THICK CLOUD COVER OVERNIGHT, SOME
PATCHY FOG MAY DEVELOP IN AREAS THAT SEE WINDS GO CALM OR
FEATURE PLENTY OF LOW LEVEL MOISTURE FROM EARLIER RAINFALL.
THE UPPER LOW/TROUGH RESPONSIBLE TO THE SHIFT TO ACTIVE WEATHER
WILL TRACK FROM THE OHIO VALLEY TOWARD THE NORTHEASTERN U.S.
THROUGH MONDAY. RELATIVE TO PREVIOUS DAYS OF MODEL RUNS, THERE
HAS BEEN A SHIFT TO A MORE PROGRESSIVE REGIME. THE ACCOMPANYING
COLD FRONT WORKS ITS WAY TO NEAR THE I-95 CORRIDOR ON MONDAY
AFTERNOON. THIS SYSTEM WILL CONTINUE TO HAVE ACCESS TO HIGHLY
ANOMALOUS TROPICAL MOISTURE WITH SIMILAR PWATS TO TODAY. A FLASH
FLOOD RISK EXISTS ALONG/EAST OF I-95, PARTICULARLY FOR AREAS
IMPACTED BY RECENT HEAVY RAINFALL. FORECAST HIGHS ON MONDAY
SHOULD AGAIN REACH THE LOW/MID 80S, WITH MAINLY 70S ACROSS
MOUNTAIN LOCALES. WHILE POST-FRONTAL WINDS BECOME NORTHWESTERLY,
HUMIDITY LEVELS REMAIN ELEVATED INTO THE NIGHT WITH LOWS IN THE
60S TO LOW 70S (MID/UPPER 50S ACROSS THE HIGHER TERRAIN).
KEY MESSAGE 2...ADDITIONAL SHOWER AND THUNDERSTORM CHANCES
TUESDAY INTO THE UPCOMING WEEKEND AHEAD.
IT'S A TYPICAL SUMMERTIME REGIME FOR REMAINDER OF THE WORKWEEK INTO
THE UPCOMING WEEKEND AS WE SIT WITHIN THE WARM SECTOR. SYNOPTICALLY,
WE ARE STILL MONITORING THE PROGRESSION OF AN UPPER LEVEL LOW
PRESSURE SYSTEM OVER THE OHIO RIVER VALLEY/CENTRAL APPALACHIANS.
THIS SYSTEM WILL BE SLOW TO PUSH EASTWARD HEADING INTO THE UPCOMING
WEEKEND. AT THE SURFACE, IS A STALLED BOUNDARY THAT WILL ACT AS A
CATALYST FOR SEVERAL PIECES OF SHORTWAVE ENERGY TO MOVE ALONG
YIELDING INCREASED CHANCES FOR SHOWERS AND THUNDERSTORMS DURING THE
DIURNAL PERIODS EACH DAY.
TUESDAY APPEARS TO BE THE DRIEST DAY OF THE NEXT 7 DAYS AS THE FRONT
STALLS DOWN ACROSS CENTRAL AND SOUTHEAST VIRGINIA WITH WEAK HIGH
PRESSURE BUILDING OVER NORTH-CENTRAL PA. STORM CHANCES LOOK TO
INCREASE WEDNESDAY THROUGH LATE WEEK AS PIECES OF SHORTWAVE ENERGY
PIVOT ACROSS THE TROUGH WITH MID LEVEL FLOW INCREASING TO 30-40 KTS
BETWEEN THE STALLED FRONT OVER THE GREAT LAKES AND STALLED FRONT TO
OUR SOUTH. THE WARM AND MOIST AIRMASS COMBINED WITH THESE PASSING
WAVES OF ENERGY WILL YIELD GREATER THUNDERSTORM COVERAGE ESPECIALLY
DURING THE AFTERNOON AND EVENING PERIODS WEDNESDAY THROUGH SUNDAY.
RIGHT NOW, CONFIDENCE REMAINS LOW FOR SEVERE WEATHER BASED ON
COVERAGE, MAGNITUDE, AND TIMING DURING THE PERIOD. SPC DOES HAVE A
MENTION FOR SEVERE WEATHER DURING THE THURSDAY THROUGH SUNDAY PERIOD
DUE TO INCREASED INSTABILITY AND MID LEVEL FLOW (30-40KTS). THIS
ALIGNS WITH 15-30 PERCENT PROBABILITIES FROM MEDIUM RANGE MACHINE
LEARNING OUTPUTS DURING THE SAME TIMEFRAME. BASED ON CURRENT 6Z/12Z
OUTPUTS, ANY FOCUS FOR SEVERE WEATHER WOULD BE ON THURSDAY WEST OF
THE BLUE RIDGE AND AGAIN FRIDAY INTO SATURDAY AS A WEAK FRONT SLIDES
THROUGH. MAIN THREATS WITH STORMS WOULD BE DAMAGING WINDS AND
LOCALLY HEAVY RAINFALL LEADING TO INSTANCES OF FLASH FLOODING GIVEN
PWATS AROUND 2 INCHES. CURRENT DROUGHT CONDITIONS SHOULD HELP US
AVOID WIDESPREAD FLOODING WOES ALTHOUGH POOR DRAINAGE AND URBAN
AREAS WILL BE THE MOST SUSCEPTIBLE OVER THE COMING DAYS AHEAD.
EXPECT OPPRESSIVE HUMIDITY WITH SEASONABLE TEMPERATURES IN THE MID
80S AND LOW 90S. THE INCREASED HUMIDITY COMBINED WITH SOME SUNSHINE
WEDNESDAY THROUGH SATURDAY WILL YIELD HEAT INDICES IN THE MID 90S
TO LOW 100S EACH AFTERNOON EAST OF THE MOUNTAINS.
AVIATION /00Z MONDAY THROUGH FRIDAY/
WIDESPREAD SHOWERS AND INTERMITTENT HEAVIER DOWNPOURS AND
THUNDERSTORMS CONTINUE TO AFFECT ALL THE TERMINALS EXCEPT MRB,
WITH THE MOST INTENSE ACTIVITY POSSIBLE THROUGH 03Z OR SO,
THOUGH SHOWERS MAY CONTINUE AFTER THAT. SHOWERS AND STORMS TO
THE WEST MAY EVENTUALLY REACH MRB BY LATE EVENING IF THEY HOLD
TOGETHER, WITH MODELS HAVING VARIOUS SIGNALS ON WHAT COVERAGE
WILL BE LIKE OVERNIGHT. EVEN IN A MORE WIDESPREAD SCENARIO,
THERE SHOULD BE A DOWNWARD TREND TOWARD DAWN.
CEILINGS WILL GRADUALLY LOWER THROUGH THE NIGHT, WITH MOST
TERMINALS LIKELY EXPERIENCING A PERIOD OF IFR LATE TONIGHT INTO
MONDAY MORNING. FOG/MIST MAY ALSO REDUCE VISIBILITY IN SOME
LOCATIONS.
FOR MONDAY, LOW CEILINGS CONTINUE IN THE MORNING BEFORE ANOTHER
ROUND OF STORMS LOOK LIKELY DURING THE AFTERNOON/EVENING HOURS.
THE LATEST MODELS HAVE STORM INITIATION FROM MTN TO DCA TO CHO,
BUT COVERAGE REMAINS UNCERTAIN. HAVE PLACED PROB30 GROUPS FOR
THE THREAT OF RESTRICTIONS DUE TO THUNDERSTORMS. WINDS SHIFT
FROM SOUTHERLY OVER TO NORTHWESTERLY ON MONDAY EVENING BEHIND
THE ASSOCIATED COLD FRONT.
EXPECT PERIODS OF SUB-VFR CONDITIONS TO CONTINUE AT TIMES
TUESDAY THROUGH THE UPCOMING WEEKEND GIVEN INCREASED CHANCES FOR
SHOWERS AND THUNDERSTORMS. THE GREATEST COVERAGE STORMS WILL BE
DURING THE AFTERNOON AND EVENING HOURS EACH DAY. NORTH TO
NORTHEAST WINDS TUESDAY SWITCHING TO THE SOUTH AND SOUTHEAST FOR
THE REMAINDER OF THE WORKWEEK.
MARINE
GIVEN SOUTHERLY CHANNELING EFFECTS, SMALL CRAFT ADVISORIES
REMAIN IN EFFECT ACROSS ALL WATERS. ASIDE FROM THE UPPER/MIDDLE
TIDAL POTOMAC, THESE REMAIN IN PLACE THROUGH THE OVERNIGHT
HOURS. WHILE A STRONG THUNDERSTORM CAN'T BE RULED OUT THROUGH
THE NIGHT, RECENT RADAR TRENDS SUGGEST ACTIVITY WILL MAINLY
CONSIST OF SHOWERS AND PERHAPS A FEW LIGHTNING STRIKES.
SOUTHERLY GUSTS DECREASE TO AROUND 10 TO 15 KNOTS FOR MUCH OF
MONDAY, ALTHOUGH SOME UPTICKS COULD APPROACH ADVISORY LEVELS AT
TIMES. OTHERWISE, ANOTHER ROUND OF STRONGER STORMS ARE POSSIBLE
DURING THE AFTERNOON/EVENING HOURS. FURTHER SPECIAL MARINE
WARNINGS MAY BE NECESSARY WHICH WOULD LEND ITSELF TO HAZARDOUS
BOATING/SWIMMING CONDITIONS.
SUB-SCA LEVEL WINDS ARE EXPECTED OUT OF THE NORTH AND NORTHEAST
TUESDAY. SCA LEVEL SOUTHERLY CHANNELING IS EXPECTED WEDNESDAY
THROUGH FRIDAY FOR PORTIONS OF THE WATERS. A FEW SHOWERS &
THUNDERSTORMS ARE POSSIBLE OVER THE WATERS DURING THIS PERIOD DUE TO
A STALLED FRONT NEARBY. SMWS MAY BE NEEDED TO ENCOMPASS THIS THREAT
DURING THE AFTERNOON AND EVENING HOURS.
TIDES/COASTAL FLOODING
TIDAL ANOMALIES WILL CONTINUE TO REMAIN ELEVATED THROUGH MUCH
OF THE MONDAY BEFORE DROPPING TUESDAY DUE TO A WIND SHIFT.
ADDITIONAL COASTAL FLOODING IS POSSIBLE AT TIMES OF HIGH TIDE AS
SENSITIVE LOCATIONS AS A RESULT. ANNAPOLIS IS IN MINOR FLOOD
THIS EVENING AND WILL BE CLOSE AGAIN MONDAY MORNING. ANOMALIES
CLIMB AGAIN MID TO LATE WEEK.
LWX WATCHES/WARNINGS/ADVISORIES
DC...FLOOD WATCH UNTIL MIDNIGHT EDT TONIGHT FOR DCZ001.
MD...SMALL CRAFT ADVISORY UNTIL 11 AM EDT MONDAY FOR MDZ008.
FLOOD WATCH UNTIL MIDNIGHT EDT TONIGHT FOR MDZ011-013-014-504-
506.
COASTAL FLOOD ADVISORY UNTIL 11 PM EDT THIS EVENING FOR MDZ014.
FLOOD WATCH UNTIL 2 AM EDT MONDAY FOR MDZ501-502-509-510.
VA...FLOOD WATCH UNTIL MIDNIGHT EDT TONIGHT FOR VAZ053-054-527.
FLOOD WATCH UNTIL 2 AM EDT MONDAY FOR VAZ025>027-029-036>040-
503-504-507-508.
WV...FLOOD WATCH UNTIL 2 AM EDT MONDAY FOR WVZ050-055-501>506.
MARINE...SMALL CRAFT ADVISORY UNTIL 11 AM EDT MONDAY FOR ANZ530>534-
537>543.
SMALL CRAFT ADVISORY UNTIL 11 PM EDT THIS EVENING FOR ANZ535-
536.
DISCUSSION...ADS/BRO/EST
AVIATION...ADS/BRO/EST
MARINE...ADS/BRO/EST
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page