668
FXUS61 KLWX 210030
AFDLWX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
830 PM EDT SAT JUN 20 2026
WHAT HAS CHANGED
CHANCES FOR A SHOWER OR BRIEF THUNDERSTORM WERE INTRODUCED
ACROSS NORTHERN MARYLAND AND NORTHERN PORTIONS OF THE WEST
VIRGINIA PANHANDLE THIS EVENING. AS OF 815 PM, RADAR IMAGERY
SHOWS A BROKEN BAND OF SHOWERS AND A FEW EMBEDDED THUNDERSTORMS
STRETCHING FROM WEST-SOUTHWEST TO EAST-NORTHEAST ACROSS NORTH-
CENTRAL WEST VIRGINIA AND SOUTHERN PENNSYLVANIA. THESE SHOWERS
AND STORMS ARE EXPECTED TO GRADUALLY WEAKEN AS THEY DROP
SOUTHWARD INTO OUR FORECAST AREA THROUGH THE REMAINDER OF THE
EVENING, AS THEY MOVE INTO AN ENVIRONMENT CHARACTERIZED BY
LESSER LOW- LEVEL MOISTURE. LOSS OF DAYTIME HEATING SHOULD ALSO
CONTRIBUTE TO THE WEAKENING OF THESE SHOWERS/STORMS. THE 00Z IAD
SOUNDING SHOWS AN ENVIRONMENT THAT SHOULD BE VERY HOSTILE TO
ANY ONGOING STORMS, WITH AMPLE DRY AIR IN THE BOUNDARY LAYER AND
A STRONG CAPPING INVERSION AROUND 600 HPA (LCL IS AROUND 700
HPA).
KEY MESSAGES
- 1) STRONG TO SEVERE THUNDERSTORMS ALONG WITH LOCALLY HEAVY
RAINFALL POSSIBLE ON MONDAY.
- 2) AFTER A MID WEEK DRY SPELL, DAILY THUNDERSTORM
CHANCES WILL RETURN FOR THE END OF THE WEEK.
DISCUSSION
KEY MESSAGE 1...STRONG TO SEVERE THUNDERSTORMS ALONG WITH
LOCALLY HEAVY RAINFALL POSSIBLE ON MONDAY.
AFTER A SEASONABLE AND LESS HUMID WEEKEND, A LOW PRESSURE SYSTEM IS
FORECAST TO TRACK FROM THE OHIO RIVER VALLEY NORTHEAST ON MONDAY.
THE ASSOCIATED WARM FRONT WILL LIFT NORTH ACROSS THE REGION MONDAY
AFTERNOON AND INTO THE EVENING, BRINGING THE NEXT CHANCE AT SEVERE
WEATHER. THERE STILL REMAINS A GOOD BIT OF UNCERTAINTY REGARDING
TIMING AND SEVERITY OF STORMS, GIVEN THE MODEL GUIDANCE
DISCREPANCY IN THE TRACK OF THE LOW PRESSURE SYSTEM AND
ASSOCIATED FRONTS. WITH SOUTHERLY FLOW, A WARM AND MOIST AIRMASS
IS EXPECTED LEADING TO ADEQUATE INSTABILITY. ADDITIONALLY, STEEP
LOW-LEVEL LAPSE RATES WILL LEAD TO POSSIBLE DAMAGING WIND GUSTS
AS THE PRIMARY HAZARD TYPE. SPC HAS THE ENTIRE FORECAST AREA IN
A MARGINAL RISK FOR SEVERE WEATHER.
IN ADDITION TO THE SEVERE THREAT, PWATS NEARING 2 INCHES WILL
LEAD TO LOCALLY HEAVY RAINFALL WITHIN THE STRONGEST STORMS. THE
WEATHER PREDICTION CENTER AS MOST OF THE AREA IN A SLIGHT RISK
FOR EXCESSIVE RAINFALL WITH SCATTERED INSTANCES OF FLOODING
POSSIBLE.
KEY MESSAGE 2...AFTER A MID WEEK DRY SPELL, DAILY THUNDERSTORM
CHANCES WILL RETURN FOR THE END OF THE WEEK.
IT'S NOW LOOKING LIKE THE COLD FRONT MAY NOT MAKE IT ENTIRELY
THROUGH THE AREA BY TUESDAY. THEREFORE, THERE MAY BE SOME RENEWAL OF
SHOWERS AND THUNDERSTORMS AS A SHORTWAVE TROUGH SERVES TO KICK THE
FRONT EASTWARD. THE GREATEST CHANCES WILL BE ALONG AND EAST OF I-95.
TEMPERATURES WILL BE COOLER THAN MONDAY, HOWEVER.
HIGH PRESSURE WILL MOVE ACROSS THE AREA WEDNESDAY, RESULTING IN THE
MOST PLEASANT DAY OF THE WEEK. TEMPERATURES WILL BE NEAR NORMAL IN
THE MID 80S WITH RELATIVELY LOW DEW POINTS IN THE 50S AND MOSTLY
SUNNY SKIES.
A SLOW MOVING UPPER LEVEL TROUGH/CLOSED LOW AND BROAD SURFACE LOW
PRESSURE WILL SLOW LIFT THROUGH THE GREAT LAKES THURSDAY AND FRIDAY.
WHILE TEMPERATURES MAY NOT RISE APPRECIABLY, THERE WILL BE A RETURN
TO MUGGIER DEW POINTS. SPECIFIC FORCING MAY BE NEBULOUS, BUT THERE IS
A DECENT MODEL SIGNAL OF AT LEAST SCATTERED SHOWERS AND
THUNDERSTORMS EACH DAY. SOME SHEAR WILL BE PRESENT, BUT INSTABILITY
MAY BE LIMITED, SO THE SEVERE WEATHER THREAT APPEARS TO BE LOW
(SUPPORTED BY VARIOUS ML GUIDANCE PROBS).
RAIN CHANCES ON SATURDAY MAY BE LOWER AS THE UPPER LEVEL PATTERN
FLATTENS AND WEAK HIGH PRESSURE LIKELY BUILDS SOMEWHERE NEAR THE
EAST COAST. HOWEVER, MODEL SPREAD INCREASES AS AN UPPER LOW MOVES
INTO THE PACIFIC NORTHWEST AND DOWNSTREAM JET STREAM RIPPLES COULD
STILL RESULT IN SOME SHOWERS OR THUNDERSTORMS IN THE WARM AND HUMID
AIRMASS.
AVIATION /00Z SUNDAY THROUGH THURSDAY/
VFR CONDITIONS CONTINUE TONIGHT AND TOMORROW. WINDS WILL
CONTINUE TO DECREASE THIS EVENING, BUT REMAIN OUT OF THE WEST-
NORTHWEST. WINDS GUST 15 TO 20 KNOTS TOMORROW, REMAINING OUT OF
THE WEST/NORTHWEST. SHOWERS AND THUNDERSTORMS ARE POSSIBLE ON
MONDAY WITH FLIGHT RESTRICTIONS LIKELY. OUTSIDE OF STORMS,
SOUTHERLY WINDS COULD GUST TO 25 KT ASSUMING A WARM FRONT CLEARS
THE AREA TO THE NORTH.
WITH A SLOWER MOVING COLD FRONT, THUNDERSTORMS COULD DEVELOP AGAIN
ON TUESDAY AFTERNOON, ESPECIALLY FOR THE METRO TERMINALS. WEDNESDAY
WILL LIKELY BE DRY. THUNDERSTORMS ARE POSSIBLE AGAIN ON
THURSDAY.
MARINE
EARLIER SMALL CRAFT ADVISORIES WERE ALLOWED TO EXPIRE. WE
CONTINUE TO MONITOR A BROKEN BAND OF SHOWERS ACROSS SOUTHERN
PENNSYLVANIA THIS EVENING. AN MWS FOR LOCALLY HIGHER WINDS OVER
THE WATERS MAY POTENTIALLY BE NEEDED LATER THIS EVENING AS
THESE SHOWERS APPROACH THE NORTHERN BAY. OTHERWISE, WINDS ARE
EXPECTED TO DIMINISH THROUGH THE OVERNIGHT HOURS. LIGHTER AND
MORE VARIABLE WINDS ARE EXPECTED OVER THE WATERS TOMORROW. WINDS
SHIFT TO SOUTHERLY ON MONDAY WITH SMALL CRAFT ADVISORY LIKELY
NEEDED. ADDITIONALLY, SHOWERS AND THUNDERSTORMS ARE EXPECTED
ACROSS THE WATERS MONDAY AFTERNOON AND EVENING WITH SMWS
POSSIBLY NEEDED.
NORTHWEST WINDS BEHIND A COLD FRONT MAY PRESENT MARGINAL ADVISORY
CONDITIONS ON TUESDAY. ANOTHER ROUND OF THUNDERSTORMS COULD DEVELOP
TUESDAY AFTERNOON AS THE FRONT IS NOW EXPECTED TO BE SLOWER. LIGHT
WINDS ARE EXPECTED WEDNESDAY UNDER HIGH PRESSURE. THE NEXT UPPER
LEVEL DISTURBANCE COULD BRING MORE THUNDERSTORMS THURSDAY AFTERNOON.
SOUTHERLY CHANNELING ON THE BAY MAY ALSO REQUIRE SCAS BY LATE IN THE
DAY.
LWX WATCHES/WARNINGS/ADVISORIES
DC...NONE.
MD...NONE.
VA...NONE.
WV...NONE.
MARINE...NONE.
DISCUSSION...ADS/AVS/KJP
AVIATION...ADS/AVS/KJP
MARINE...ADS/AVS/KJP
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