237
FXUS61 KLWX 060600
AFDLWX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
200 AM EDT SAT SEP 6 2025
SYNOPSIS
A STRONG COLD FRONT WILL CROSS THE AREA TODAY. THE FRONT WILL
BRING STRONG TO SEVERE THUNDERSTORMS TO PORTIONS OF THE AREA,
FOLLOWED BY ANOTHER PROLONGED STRETCH OF COOLER WEATHER.
CANADIAN HIGH PRESSURE WILL BUILD IN FROM THE WEST MONDAY
BEFORE SETTLING TO THE NORTH OF THE AREA TUESDAY AND WEDNESDAY.
A DRY COLD FRONT WILL APPROACH THURSDAY, WITH HIGH PRESSURE
RETURNING TO END THE WEEK.
NEAR TERM /THROUGH TONIGHT/
AS OF EARLY THIS MORNING (06Z/2AM EDT), REMNANT CONVECTION WAS
PIVOTING ACROSS WESTERN MD, ACCOMPANIED BY OCCASIONAL LIGHTNING
STRIKES AND DOWNPOURS. GIVEN MINIMAL CAPE AND WEAK FORCING FOR
ASCENT, THIS CONVECTION IS NOT EXPECTED TO BE SEVERE, AND WILL
PROBABLY NOT MAKE IT TOO MUCH FARTHER EAST THROUGH DAYBREAK (IF
IT LASTS THAT LONG); ADDITIONAL WEAKENING CONVECTION IS SLOWLY
APPROACHING THE APPALACHIANS IN WV/VA/MD. LEFTOVERS FROM THIS
CONVECTION (I.E. BOUNDARIES AND CLOUD DEBRIS) WILL PROVE PIVOTAL
TO DOWNSTREAM CONVECTIVE RISK LATER TODAY.
IT WILL BE A DAY OF TRANSITION ACROSS THE REGION AND A MATTER
OF LOCATION WHEN IT COMES TO THE POTENTIAL FOR SEVERE WEATHER.
DEEP UPPER TROUGHING WILL REMAIN IN PLACE ACROSS MUCH OF EASTERN
CONUS, WITH THE PRIMARY TROUGH AXIS EXTENDING FROM HUDSON BAY
SOUTHWARD THROUGH THE GREAT LAKES AND MISSISSIPPI VALLEY. A
SHORTWAVE/MID-LEVEL SPEED MAX WILL LIFT NORTHEASTWARD THROUGH
THE FRONTSIDE OF THE TROUGH THIS MORNING, TRACKING FROM THE OHIO
VALLEY TOWARD THE ST. LAWRENCE VALLEY THIS AFTERNOON. LOCALLY,
WE'LL EXPERIENCE WEAK HEIGHT FALLS ALOFT, AND ALSO BECOME
LOCATED WITHIN THE EQUATORWARD ENTRANCE REGION OF AN
UNSEASONABLY STRONG UPPER JET STREAK. AT THE SURFACE, THE
SYSTEM'S COLD FRONT WILL TRACK SOUTHEASTWARD ACROSS THE AREA
THIS AFTERNOON INTO EARLY EVENING. THUNDERSTORMS WILL INITIATE
ALONG THIS BOUNDARY ESPECIALLY IN AREAS ALONG AND EAST OF I-81
EARLY TO MID AFTERNOON (12-4PM) BEFORE ADVANCING TOWARD THE
BALTIMORE/DC METROS BY LATE AFTERNOON/EARLY EVENING (3-8PM).
MODEL SOUNDINGS CONTINUE TO SHOW AROUND 1000-2000 J/KG OF
MLCAPE AND AROUND 35-50 KNOTS OF EFFECTIVE BULK SHEAR. WELL
ORGANIZED THUNDERSTORMS ARE EXPECTED AS A RESULT, WITH BOTH
MULTICELLS AND EVEN A FEW SUPERCELLS POSSIBLE. DAMAGING WINDS
SHOULD BE THE PRIMARY THREAT, BUT AN INSTANCE OR TWO OF LARGE
HAIL CAN'T BE RULED OUT IN ANY SUPERCELLS THAT FORM. HODOGRAPHS
ARE PRIMARILY STRAIGHT AND THERE ALSO ISN'T MUCH LOW-LEVEL SHEAR
PRESENT, SO TORNADOES AREN'T EXPECTED. WITH THE STRONG FLOW IN
PLACE ALOFT, STORMS SHOULD BE RATHER PROGRESSIVE. AS A RESULT,
FLASH FLOODING ISN'T EXPECTED TO BE A MAJOR ISSUE. HOWEVER, A
STRAY INSTANCE OF FLOODING CAN'T BE RULED OUT IF THUNDERSTORMS
WERE TO TRAIN OVER A HIGHLY URBANIZED LOCATION. BOTH SPC AND WPC
HAVE LOCATIONS ROUGHLY TO THE EAST OF I-81 OUTLOOKED IN
MARGINAL RISKS FOR SEVERE THUNDERSTORMS AND FLASH FLOODING,
RESPECTIVELY. A SLIGHT RISK FROM SPC CLIPS FAR NORTHEASTERN
PORTIONS OF MARYLAND (HARFORD AND CECIL COUNTIES). THE BEST
PARAMETER SPACE MAY RESIDE JUST TO THE NORTHEAST OF THE AREA
(I.E NJ/NY). THUNDERSTORMS WILL CLEAR SOUTHERN MARYLAND BY MID
EVENING (9PM), WITH JUST A FEW LINGERING LIGHT SHOWERS AND
PATCHY FOG POSSIBLE OVERNIGHT. WINDS WILL SHIFT TO OUT OF THE
NORTH TO NORTHWEST BEHIND THE FRONT, ALLOWING COOLER AND DRIER
AIR TO FILTER INTO THE REGION OVERNIGHT.
THE EXACT PLACEMENT OF THE FRONT AND ANY RESIDUAL CLOUD
DEBRIS/SHOWER ACTIVITY WORKING EAST FROM THE ALLEGHENIES IN THE
MORNING WILL HAVE A SIGNIFICANT EFFECT ON TEMPERATURES. OVERALL,
EXPECT HIGHS EAST OF OF THE BLUE RIDGE IN THE MID 80S TO LOW
90S. LOCATIONS FURTHER WEST WILL LIKELY SEE HIGHS IN THE 70S AND
LOW TO MID 80S. LOW-LEVEL MOISTURE WILL ALSO BE ON THE INCREASE
TO THE EAST OF THE FRONT WITH DEWPOINTS CLIMBING BACK INTO THE
UPPER 60S TO NEAR 70 ALONG AND EAST OF THE BLUE RIDGE. BY PEAK
HEATING, MOST GUIDANCE HAS THE FRONT EXTENDING FROM NORTH-
CENTRAL MARYLAND SOUTHWESTWARD THROUGH THE WESTERN DC SUBURBS
INTO THE SHENANDOAH VALLEY.
THE FRONT WILL MOVE OFFSHORE OVERNIGHT, AND MAY RESULT IN A WIDE
TEMPERATURE SPREAD RANGING FROM THE 40S OVER THE APPALACHIANS TO
THE MID 60S IN THE I-95 MAJOR CITY CENTERS.
SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/
UPPER TROUGHING WILL CONTINUE TO MAKE SLOW EASTWARD PROGRESS ON
SUNDAY WITH A FINAL EMBEDDED SHORTWAVE TRACKING FROM THE OHIO
VALLEY TOWARD PENNSYLVANIA BY SUNDAY EVENING. A MIX OF SUN AND
CLOUDS IS EXPECTED, WITH MORE CLOUDS TOWARD THE SOUTHEAST AND
MORE SUN TOWARD THE NORTHWEST. A MORNING SHOWER OR TWO COULD
ALSO BE POSSIBLE NEAR/EAST OF I-95. WINDS WILL BE OUT OF THE
NORTHWEST, AND TEMPERATURES WILL BE MUCH COOLER, WITH HIGHS IN
THE 70S (60S IN THE MOUNTAINS). LOWS SUNDAY NIGHT WILL FALL INTO
THE UPPER 40S AND LOW 50S FOR MOST. MOUNTAIN LOCATIONS AND
RIVER VALLEY LOCATIONS WEST OF THE BLUE RIDGE WILL SEE LOWS IN
THE LOW TO MID 40S. SOME HIGH VALLEY LOCATIONS (I.E BITTINGER,
MD, CANAAN VALLEY, WV, AND MILL GAP, VA) COULD SEE LOWS DROP
INTO THE 30S.
SKIES WILL TREND MOSTLY SUNNY WITH AMPLE DRY AIR ADVECTION
FUNNELING INTO THE REGION ON MONDAY. HIGH TEMPERATURES MAY BE A
TOUCH WARMER THAN SUNDAY OWING TO MORE SUNSHINE. LOWS MONDAY
NIGHT WILL FALL BACK INTO THE MID 40S AND MID 50S; URBAN
LOCATIONS AND LOCATIONS DIRECTLY ALONG THE CHESAPEAKE BAY WILL
SEE LOWS IN THE UPPER 50S AND LOW 60S WITH MOUNTAIN AREAS SEEING
LOWS IN THE LOW TO MID 40S.
LONG TERM /TUESDAY THROUGH FRIDAY/
HIGH PRESSURE WILL REMAIN OVERHEAD TUESDAY BRINGING MOSTLY SUNNY
SKIES. WHILE THE RIDGE REMAINS CENTERED OVER THE NORTHEASTERN U.S.,
AN APPROACHING LONGWAVE TROUGH WILL STRENGTHEN A STALLED FRONTAL
ZONE WHICH STRADDLES THE CAROLINA TO SOUTHEASTERN U.S. COAST. SOME
ISENTROPIC LIFT ATOP THIS BOUNDARY MAY EVEN SQUEAK OUT A FEW SHOWERS
OVER SOUTHERN MARYLAND ON WEDNESDAY. HOWEVER, THE CHANCES DO REMAIN
LOW AT THIS POINT, GENERALLY AROUND 15 TO 20 PERCENT. THIS DOES
INTRODUCE PLENTY OF CLOUD COVER FOR THOSE EAST OF THE BLUE RIDGE
MOUNTAINS, HOWEVER.
THE AMPLIFIED FLOW GRADUALLY TRACKS ANOTHER REINFORCING COLD FRONT
ACROSS THE REGION ON THURSDAY. GIVEN VERY LITTLE MOISTURE TO WORK
WITH, THIS SHOULD PROVE TO BE A DRY FRONTAL PASSAGE. THIS ALSO
ALLOWS FOR A RETURN TO MOSTLY SUNNY SKIES EACH DAY TO CONCLUDE THE
UPCOMING WORK WEEK.
FOR HIGH TEMPERATURES, MOST LOCATIONS CAN EXPECT DAILY READINGS IN
THE LOW/MID 70S (UPPER 50S TO LOW 60S ACROSS MOUNTAIN LOCALES). AT
NIGHT, MANY PERIODS OF AMPLE RADIATIONAL COOLING WILL DRAW LOW
TEMPERATURES INTO THE UPPER 40S TO MID 50S (LOW/MID 40S FROM I-81
WESTWARD). SOME UPTICK IN OVERNIGHT LOWS ARE POSSIBLE BY MID-WEEK
GIVEN THE INCREASED CLOUD COVER. ADDITIONALLY, THE POST-FRONTAL AIR
MASS ON THURSDAY MAY YIELD SOME HIGHS INTO THE LOW 80S OWING TO
DOWNSLOPING WINDS. TEMPERATURES DO COOL OFF IN THE WAKE OF THIS
BOUNDARY BY NEXT FRIDAY.
AVIATION /06Z SATURDAY THROUGH WEDNESDAY/
VFR CONDITIONS AND SOUTHERLY WINDS ARE EXPECTED TO CONTINUE AT ALL
TERMINALS THROUGH EARLY THIS MORNING. WINDS WILL REMAIN LESS
THAN 10 KTS WHILE SLOWLY TURNING TO THE SOUTHWEST MID TO LATE
THIS MORNING INTO THIS AFTERNOON AHEAD OF AN APPROACHING COLD
FRONT. EXPECT SPEEDS NEAR 10 KTS WITH GUSTS UP TO 15 KTS AS THE
FRONT PASSES THROUGH. THUNDERSTORMS WILL ALSO ACCOMPANY THE
COLD FRONT AS IT PASSES. HIGHEST CONFIDENCE FOR THUNDERSTORMS
APPEARS TO BE AT TERMINALS EAST OF KMRB AND KSHD MAINLY BETWEEN
17Z-00Z/1-8PM EDT. THUNDERSTORMS WILL WORK INTO AREAS AROUND
KIAD/KCHO/KFDK BETWEEN 17Z-21Z/1-5PM EDT BEFORE QUICKLY RACING
EAST TOWARD THE I-95 CORRIDOR TERMINALS BETWEEN 19Z-22Z/3-6PM.
ALL OF THE ACTIVITY SHOULD SINK SOUTH AND EAST OF THE CORRIDOR
TOWARD KRIC BY 23Z-01Z/7-9PM EDT. OVERALL COVERAGE APPEARS
SCATTERED SOUTH OF KIAD GIVEN A LITTLE LESS FORCING. MORE LINEAR
ORGANIZATION OF STORMS WILL BE NOTED FROM IAD/DCA POINTS
NORTHWARD TOWARD KBWI/KPHL WHERE BETTER FORCING AND INSTABILITY
RESIDE. DAMAGING WINDS WILL BE THE PRIMARY THREAT WITH THUNDERSTORMS
ALONG WITH LOCALLY HEAVY RAINFALL AND PERHAPS ISOLATED LARGE
HAIL. A PERIOD OF PATCHY FOG/LOW CIGS IS POSSIBLE THIS EVENING
INTO THE OVERNIGHT, BUT CONFIDENCE IS LOW ESPECIALLY FURTHER NORTH
GIVEN A POTENTIAL INTRUSION OF DRIER AIR. VFR CONDITIONS RETURN
SUNDAY AS THE FRONT CLEARS THE AREA. A LEFTOVER SHOWER OR TWO
IS POSSIBLE OVER THE METRO CORRIDOR AS THE FRONT SLOWS EARLY
SUNDAY MORNING. WINDS WILL SHIFT TO THE NORTH AND NORTHWEST
BEHIND THE FRONT WITH GUSTS UP TO 15 KTS. LIGHTER NW TO NE
WINDS ARE EXPECTED MONDAY WITH VFR CONDITIONS.
A DRY PATTERN IS IN PLACE ON TUESDAY OWING TO BROAD CANADIAN HIGH
PRESSURE SETTLING OVER THE NORTHEASTERN U.S. THIS WILL ENSURE VFR
CONDITIONS. BY WEDNESDAY, A COASTAL BOUNDARY MAY INCREASE
CLOUDS EAST OF THE BLUE RIDGE. HOWEVER, THESE ARE NOT LIKELY TO
CAUSE ANY RESTRICTIONS. WIND FIELDS DURING THE PERIOD WILL
LARGELY BE EAST-NORTHEASTERLY AS HIGH PRESSURE TRACKS NORTH OF
THE AREA.
MARINE
SOUTHERLY WINDS WILL GRADUALLY SUBSIDE THROUGH THE MORNING
HOURS. WINDS POTENTIALLY PICK BACK UP IN CHANNELED SOUTHERLY
FLOW THIS AFTERNOON AND EVENING AHEAD OF AN APPROACHING COLD
FRONT. SMWS WILL LIKELY BE NEEDED THIS AFTERNOON/EVENING
(2-9PM) AS GUSTY THUNDERSTORMS MOVE OVER THE WATERS. WINDS WILL
TURN OUT OF THE NORTH TO NORTHWEST TONIGHT BEHIND THE COLD
FRONT AND REMAIN NORTHWESTERLY DURING THE DAY SUNDAY. A FEW SCA
GUSTS MAY BE POSSIBLE IN NORTH TO NORTHWESTERLY FLOW, AS WELL.
LIGHTER NW TO NE WINDS ARE EXPECTED MONDAY
THE COMBINATION OF HIGH PRESSURE OVER THE NORTHEASTERN U.S. AND A
FRONTAL ZONE OFF THE SOUTHEASTERN U.S. WILL INCREASE OVERALL
PRESSURE GRADIENTS TUESDAY; CONSEQUENTLY, SOME MARINE WINDS
COULD NEAR SMALL CRAFT ADVISORY LEVELS. GRADIENTS RELAX SOME
WEDNESDAY RESULTING IN SLIGHTLY LOWER WINDS.
TIDES/COASTAL FLOODING
AFTER NEAR MINOR FLOODING ALONG VULNERABLE SHORELINE EARLY THIS
MORNING, A WIND SHIFT FOLLOWING THE PASSAGE OF A STRONG COLD
FRONT SHOULD RESULT IN DECREASING WATER LEVELS TONIGHT THROUGH
AT LEAST EARLY MONDAY.
LWX WATCHES/WARNINGS/ADVISORIES
DC...NONE.
MD...COASTAL FLOOD ADVISORY UNTIL 7 AM EDT THIS MORNING FOR MDZ014.
VA...NONE.
WV...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 3 AM EDT EARLY THIS MORNING FOR
ANZ530>534-537-539>543.
SYNOPSIS...DHOF/EST
NEAR TERM...DHOF/KJP/EST
SHORT TERM...DHOF/KJP/EST
LONG TERM...CPB
AVIATION...DHOF/KJP/CPB/EST
MARINE...DHOF/KJP/CPB/EST
TIDES/COASTAL FLOODING...LWX
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