385
FXUS61 KLWX 300040
AFDLWX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
840 PM EDT SUN JUN 29 2025
SYNOPSIS
ADDITIONAL SHOWER AND THUNDERSTORM CHANCES ARE EXPECTED MONDAY
WITH A FRONT REMAINING NEARBY. A STRONGER COLD FRONT LOOKS TO
CROSS TUESDAY BRINGING WIDESPREAD STRONG TO SEVERE THUNDERSTORMS
TO THE AREA. LESS HUMIDITY AND DRIER CONDITIONS ARE EXPECTED AS
HIGH PRESSURE BUILDS WEDNESDAY INTO LATE WEEK.
NEAR TERM /UNTIL 6 AM MONDAY MORNING/
LATEST RADAR/SATELLITE SHOWS SHOWER AND THUNDERSTORM ACTIVITY
GENERALLY WEAKENING, BUT WITH A FEW REMAINING OUTFLOW BOUNDARIES
IN A HUMID AND MODERATELY UNSTABLE AIRMASS PER MESOANALYSIS.
SOME GUIDANCE INDICATES A CHANCE FOR A COUPLE OF HEAVY SHOWERS
OR THUNDERSTORMS DEVELOPING ALONG COLLIDING OUTFLOWS NEAR THE
BROADER DC AREA THROUGH ABOUT 10 OR 11PM.
OTHERWISE, A SHOWER OR TWO CAN'T BE RULED OUT OVERNIGHT MAINLY
EAST OF US-15 IN THE HUMID AIRMASS WITH A WEAK FRONT OVERHEAD.
LOWS WILL ONCE AGAIN FALL BACK INTO THE UPPER 60S AND LOW 70S.
SOME PATCHY FOG MAY ALSO TRY TO FORM (ESPECIALLY IN THE RIVER
VALLEYS AND NEAR AREA WATERWAYS) PRIOR TO DAYBREAK MONDAY.
SHORT TERM /6 AM MONDAY MORNING THROUGH TUESDAY NIGHT/
MORE OF THE SAME CAN BE EXPECTED MONDAY, ALTHOUGH THE COVERAGE
OF SHOWERS AND THUNDERSTORMS MAY BE A BIT MORE WIDESPREAD ACROSS
THE REGION. WARM AND HUMID CONDITIONS WILL REMAIN WITH HIGHS
CLIMBING INTO THE UPPER 80S AND LOW 90S. HEAT INDICES WILL ALSO
SIT CLOSE TO 100 DEGREES ESPECIALLY EAST OF US-15 AND INTO THE
BALTIMORE/DC METRO AREAS. SHOWERS AND THUNDERSTORMS WILL FORM AS
A RESULT OF THE HEAT AND HUMIDITY BETWEEN 1-8PM. CURRENT 12Z
CAMS SHOW SLIGHTLY GREATER INSTABILITY (2500-3500 J/KG MLCAPE),
AND SLIGHTLY STRONGER MID-LEVEL FLOW (AROUND 15-20 KNOTS), WITH
CONTINUED DEEP NEAR-SATURATION AND MODEST DCAPE VALUES (500-900
J/KG). THIS WILL YIELD STORMS WITH SLIGHTLY BETTER ORGANIZATION
ESPECIALLY WEST OF I-81 AND TOWARD THE ALLEGHENIES GIVEN THE
PROXIMITY OF THE INCUMBENT PRE-FRONTAL UPPER-LEVEL TROUGH AND
COLD FRONTAL BOUNDARY. PWATS WILL REMAIN AROUND OR JUST ABOVE 2"
YIELDING RAIN RATES OF 1-2"/HR AND THE CONCERN FOR ISOLATED
INSTANCES OF FLOODING. OVERALL WIND (I.E WET MICROBURSTS) WILL
BE THE MAIN THREAT WITH STORMS MONDAY. BOTH SPC AND WPC ONCE
AGAIN HAVE THE BULK OF THE AREA OUTLOOKED IN MARGINAL RISKS.
STORMS WILL DIMINISH WITH THE LOSS OF DAYTIME HEATING WITH
PATCHY FOG LATE. LOWS MONDAY NIGHT WILL SIT IN THE LOW TO MID
70S.
A STRONGER COLD FRONT WILL CROSS THE REGION TUESDAY BRINGING
WIDESPREAD STRONG TO SEVERE THUNDERSTORMS. THE FRONT AND UPPER-LEVEL
TROUGH WILL FINALLY PUT AN END TO THE PROLONGED STRETCH OF HIGH
HUMIDITY AND STORMY CONDITIONS FOR THE REMAINDER OF THE
WORKWEEK. THE COLD FRONT WILL APPROACH FROM THE NORTHWEST
TUESDAY AFTERNOON BEFORE CROSSING TUESDAY NIGHT. MEANWHILE, THE
PRE-FRONTAL TROUGH WILL IGNITE STORMS AHEAD OF THE BOUNDARY
TUESDAY AFTERNOON AND EVENING. STORMS WILL INITIATE OVER THE
MOUNTAINS FIRST BEFORE WORKING EAST TOWARD THE METROS BY LATE
AFTERNOON AND EVENING. FLOW WILL INCREASE ALOFT YIELDING BETTER
ORGANIZATION ALONG WITH A HIGHER DAMAGING WIND THREAT AREA WIDE.
ISOLATED INSTANCES OF FLOODING ALSO CANNOT BE RULED OUT,
ESPECIALLY ALONG AND EAST OF I-95 WHERE SOME TRAINING MAY OCCUR.
SOME HAIL IS ALSO POSSIBLE AS WELL WITHIN STRONGER UPDRAFTS.
MLCAPE VALUES WILL ONCE AGAIN BE UP AROUND 2000-3500 J/KG WITH
DCAPE AROUND 1000 J/KG. 0-6 KM SHEAR VALUES WILL SIT BETWEEN
30-45 KTS ALLOWING FOR STORMS TO MOVE ALONG IN MORE OF A
PROGRESSIVE NATURE. SPC NOW OUTLINES AREAS EAST OF THE BLUE
RIDGE IN A SLIGHT RISK (LEVEL 2 OF 5) FOR SEVERE WEATHER FOR
THE ENTIRE AREA TUESDAY AFTERNOON. WPC HAS A SLIGHT RISK FOR
EXCESSIVE RAIN ALONG AND EAST OF THE I-95 CORRIDOR.
STORMS WILL DIMINISH TUESDAY NIGHT AS THE TROUGH AXIS WORKS EAST AND
HIGH PRESSURE BUILDS IN FROM THE WEST. THIS WILL LEAD TO
TRANQUIL CONDITIONS AND LESS HUMIDITY FOR THE REMAINDER OF THE
WORKWEEK. HIGHS TUESDAY WILL PUSH INTO THE MID TO UPPER 80S AND
LOW 90S WITH OVERNIGHT LOWS IN THE 60S.
LONG TERM /WEDNESDAY THROUGH SUNDAY/
HIGH PRESSURE WILL BUILD IN FROM THE WEST WEDNESDAY BRINGING
LOWER HUMIDITY AND DRIER CONDITIONS. A REINFORCING MID-LEVEL
TROUGH WILL PUSH THROUGH THE AREA THURSDAY BRINGING A THREAT OF
ISOLATED THUNDERSTORMS. ANY MOISTURE AVAILABLE LOOKS TO BE VERY
SHALLOW, SO COVERAGE IS EXPECTED TO BE ISOLATED TO WIDELY
SCATTERED AT BEST. CAPPED POPS AT 15 TO 20 PERCENT WITH A FOCUS
MAINLY WEST OF THE BLUE RIDGE.
RIDGING IS EXPECTED TO BUILD OVER THE EAST COAST STATES THROUGH
THE REST OF THE WEEK SUPPORTING WARM AND DRY/TRANQUIL
CONDITIONS WITH LOW HUMIDITY FOR THE UPCOMING HOLIDAY WEEKEND.
AVIATION /01Z MONDAY THROUGH FRIDAY/
VFR CONDITIONS ARE EXPECTED TO PREVAIL OVERNIGHT, THOUGH A
THUNDERSTORM MAY POP UP NEAR DCA THROUGH 02-03Z. SOME PATCHY
FOG MAY BE POSSIBLE AGAIN TONIGHT, ESPECIALLY IN AREAS THAT
RECEIVED RAIN DURING THE DAYLIGHT HOURS. HIGHEST CONFIDENCE FOR
MVFR TO IFR VSBYS WILL BE A KCHO AND KMRB. WINDS WILL SWITCH TO
THE NORTHWEST AT LESS THAN 10 KTS.
VFR CONDITIONS ARE EXPECTED AT ALL TERMINALS MONDAY WITH THE
EXCEPTION OF BRIEF MVFR CONDITIONS IN STRONG THUNDERSTORMS
DURING THE AFTERNOON AND EVENING HOURS. ONCE AGAIN, TIMING WILL
BE HARD TO PINPOINT FOR IMPACTS GIVEN THE LACK OF ANY WELL
DEFINED SURFACE FEATURES THAT STORMS MAY FORM OFF OF. OVERALL
COVERAGE WILL BE SCATTERED WITH A FOCUS WEST OF THE CORRIDOR AND
DOWN TOWARD KCHO/KSHD EARLY IN THE AFTERNOON WITH A SLIDE EAST
TOWARD THE CORRIDOR IAD/BWI/DCA LATE AFTERNOON INTO THE EARLY
EVENING HOURS. NUMEROUS SHOWERS AND THUNDERSTORMS ARE EXPECTED
TUESDAY AFTERNOON AND EVENING, SOME POSSIBLY SEVERE WITH
DAMAGING WINDS. VFR CONDITIONS ARE LIKELY FOR WEDNESDAY AND
THURSDAY WITH HIGH PRESSURE NEARBY. AN ISOLATED SHOWER OR
THUNDERSTORM CANNOT BE RULED OUT THURSDAY AFTERNOON WEST OF THE
CORRIDOR AS A SECONDARY SHORTWAVE TROUGH AND WEAK COLD FRONT
PASS THROUGH.
MARINE
SUB-SCA LEVEL WINDS ARE EXPECTED TO CONTINUE THROUGH MONDAY MORNING.
WINDS WILL SWITCH BACK TO THE SOUTH MONDAY AND SOUTHWEST
TUESDAY. SOME CHANNELING IS POSSIBLE ESPECIALLY OVER THE OPEN
AND MIDDLE WATERS MONDAY AFTERNOON AND EVENING. EXPECT THE
CHANCE OF AN SMW OR TWO MONDAY AFTERNOON AND EVENING AS A
RESULT OF SCATTERED SHOWERS AND THUNDERSTORMS. LOW-END SCA
CONDITIONS ARE EXPECTED TUESDAY AS THE GRADIENT TIGHTENS AHEAD
OF AN APPROACHING COLD FRONT AND PRE-FRONTAL TROUGH APPROACHING FROM
THE OHIO RIVER VALLEY. SEVERE T-STORMS ARE LIKELY TUESDAY
AFTERNOON AND EVENING, WHICH MAY REQUIRE SMWS.
SUB-SCA LEVEL WINDS ARE EXPECTED WEDNESDAY THROUGH FRIDAY AS
HIGH PRESSURE BUILDS OVER THE REGION. A DRY COLD FRONT WILL PASS
THROUGH THE AREA FRIDAY INTO THE START OF THE HOLIDAY WEEKEND.
LWX WATCHES/WARNINGS/ADVISORIES
DC...NONE.
MD...NONE.
VA...NONE.
WV...NONE.
MARINE...NONE.
SYNOPSIS...DHOF/EST
NEAR TERM...DHOF/EST
SHORT TERM...DHOF/EST
LONG TERM...LFR
AVIATION...LFR/DHOF/EST
MARINE...LFR/DHOF/EST
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