159
FXUS61 KLWX 081242
AFDLWX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
842 AM EDT TUE SEP 8 2026
WHAT HAS CHANGED
CANCELLED THE COASTAL FLOOD ADVISORY FOR SOUTHEAST HARFORD.
KEY MESSAGES
- 1) DRY THROUGH MID WEEK.
- 2) SHOWER AND THUNDERSTORM CHANCES RETURN THURSDAY.
- 3) COOLER AND LESS HUMID CONDITIONS ARE EXPECTED ON
FRIDAY, BEFORE HUMIDITY BUILDS BACK IN NEXT WEEKEND.
DISCUSSION
KEY MESSAGE 1...DRY THROUGH MID WEEK.
CONDITIONS WILL REMAIN TRANQUIL AS HIGH PRESSURE PERSISTS OVER
THE MID-ATLANTIC THROUGH WEDNESDAY BEFORE GRADUALLY MOVING
OFFSHORE. LARGE SCALE SUBSIDENCE AND DRY AIR LEAD TO A
PRECIPITATION-FREE FORECAST WITH TEMPERATURES RISING TO SEVERAL
DEGREES ABOVE NORMAL AS THE HIGH PULLS OFFSHORE. THIS LEADS TO
HIGH TEMPERATURES IN THE MID TO UPPER 80S TODAY, PERHAPS NEAR
90 WEDNESDAY (SLIGHTLY COOLER IN THE MOUNTAINS). LOW
TEMPERATURES (AND DEW POINTS) WILL GENERALLY BE IN THE 50S AND
60S DURING THIS TIME. SOME RIVER VALLEY FOG IS LIKELY EACH
MORNING.
KEY MESSAGE 2...SHOWER AND THUNDERSTORM CHANCES RETURN THURSDAY.
THE UPPER-LEVEL RIDGE WILL BEGIN TO FLATTEN OUT WEDNESDAY BEFORE
BREAKING DOWN AND PUSHING SOUTH AND EAST INTO THURSDAY. SEVERAL
PIECES OF UPPER-LEVEL ENERGY ROTATING AROUND AN UPPER LOW
CENTERED OVER THE HUDSON BAY WILL SLOWLY PUSH A COLD FRONT SOUTH
TOWARDS OUR REGION BY THURSDAY. AT THE SURFACE, HIGH PRESSURE
PUSHING OFFSHORE WILL BRING INCREASINGLY WARM AND HUMID
CONDITIONS TO THE AREA, WITH HIGHS IN THE 80S TO NEAR 90 WITH
DEW POINTS IN THE UPPER 60S TO LOW 70S, WITH THE HIGHEST VALUES
BEING THURSDAY.
MODEL GUIDANCE OVER THE PAST 24 HOURS HAS COME INTO BETTER AGREEMENT
IN REGARDS TO THE PROGRESSION OF THE FRONT ON THURSDAY, AS WELL AS
THE UPPER-LEVEL PATTERN IN ASSOCIATION WITH IT. THE FRONT
REALLY LOOKS LIKE IT WILL FLATTEN OUT AS IT MOVES SOUTHWARD, AND
REALLY LOSES THE UPPER-LEVEL SUPPORT. THE TIMING OF PEAK
HEATING AND THE HIGHEST SHEAR JUST DOESN'T LOOK TO LINE UP AT
THIS POINT. THERE MAY BE SOME JET-INDUCED SHOWERS AND STORMS
LATE THURSDAY AS WE MOVE INTO THE RIGHT ENTRANCE OF THE UPPER
JET CENTERED OVER NEW ENGLAND, BUT NOT NECESSARILY EXPECTING
THOSE TO BE SEVERE AT THAT POINT, AS THE FRONT SHOULD BE LARGELY
THROUGH THE REGION. AT THIS POINT, THE SEVERE WEATHER THREAT
LOOKS VERY LIMITED, BUT ANY STORM THAT DEVELOPS ON THE WARM SIDE
OF THE BOUNDARY COULD BRING SOME GUSTY WINDS ALONG WITH IT, BUT
THE LACK OF A SUBSTANTIAL WIND FIELD WILL REALLY MAKE THAT MORE
DIFFICULT WITH SOUTHWARD EXTENT.
KEY MESSAGE 3...COOLER AND LESS HUMID CONDITIONS ARE EXPECTED
ON FRIDAY, BEFORE HUMIDITY BUILDS BACK IN NEXT WEEKEND.
HIGH PRESSURE WILL BUILD TO OUR NORTH ON FRIDAY IN THE WAKE OF
THURSDAY'S FRONTAL PASSAGE. COOLER AND DRIER AIR WILL ADVECT INTO
THE REGION FROM THE NORTH IN ADVANCE OF THE APPROACHING HIGH. MOSTLY
SUNNY SKIES ARE EXPECTED, WITH HIGH TEMPERATURES IN THE UPPER 70S
AND LOWER 80S. IT WILL ALSO FEEL CONSIDERABLY LESS HUMID, WITH
DEWPOINTS DROPPING INTO THE UPPER 50S AND LOWER 60S.
HIGH PRESSURE WILL MOVE OFFSHORE AND A STRONG AREA OF LOW PRESSURE
WILL TRACK ACROSS HUDSON BAY ON SATURDAY, CAUSING WINDS TO TURN OUT
OF THE SOUTH IN RESPONSE. SOUTHERLY WINDS WILL ADVECT A MORE HUMID
AIRMASS BACK INTO THE AREA, WITH DEWPOINTS CLIMBING INTO THE UPPER
60S AND LOWER 70S. CHANCES FOR AFTERNOON SHOWERS AND THUNDERSTORMS
WILL ACCOMPANY THE MORE HUMID AIRMASS. BOTH INSTABILITY AND SHEAR
VALUES ARE FORECAST TO REMAIN LOW, SO ANY STORMS THAT DO FORM ARE
EXPECTED TO STAY ON THE WEAKER SIDE.
MODEL GUIDANCE BEGINS TO DIVERGE A BIT BY SUNDAY AND MONDAY, BUT
MOST SOLUTIONS FAVOR CONTINUED ABOVE AVERAGE TEMPERATURES, WITH
HIGHS IN THE MID TO UPPER 80S. ENSEMBLE GUIDANCE SUGGESTS THAT
CHANCES FOR AFTERNOON SHOWERS AND THUNDERSTORMS SHOULD TREND
DOWNWARD AS SATURDAY'S SYSTEM TRACKS FURTHER EAST ACROSS CANADA
WITHIN ZONAL FLOW, BUT THERE ARE A FEW SOLUTIONS (SUCH AS THE 12Z
CANADIAN) THAT FAVOR A MORE AMPLIFIED LONGWAVE PATTERN AND GREATER
CHANCES FOR SHOWERS AND THUNDERSTORMS.
AVIATION /12Z TUESDAY THROUGH SATURDAY/
VFR CONDITIONS ARE EXPECTED TO PREVAIL THROUGH THE END OF THE
WEEK, WITH TWO EXCEPTIONS. EARLY MORNING RIVER VALLEY FOG COULD
AFFECT MAINLY KCHO/KMRB EACH DAY ROUGHLY 08Z-13Z. THEN, SOME
SHOWER AND THUNDERSTORM ACTIVITY COULD BRING BRIEF RESTRICTIONS
ON THURSDAY (MAINLY IN THE AFTERNOON AND/OR EVENING). LIGHT
WINDS BECOME S TODAY, THEN REMAIN S THROUGH THURSDAY UNTIL A
COLD FRONT BRINGS A SHIFT TO W/NW.
PREVAILING VFR CONDITIONS ARE EXPECTED ON FRIDAY AND SATURDAY,
ALTHOUGH A PASSING THUNDERSTORM CAN'T BE RULED OUT SATURDAY
AFTERNOON. WINDS WILL GENERALLY BE LIGHT OUT OF THE NORTH TO
NORTHWEST ON FRIDAY, AND THEN LIGHT OUT OF THE SOUTH TO SOUTHEAST
ON SATURDAY.
MARINE
HIGH PRESSURE WILL RESULT IN LIGHT NORTHEAST WINDS BECOMING
SOUTH THROUGH TUESDAY. WINDS MAY INCREASE BRIEFLY EARLY
WEDNESDAY MORNING AS THE HIGH SHIFTS OFFSHORE, BUT ARE MORE
LIKELY TO INCREASE IN SOUTHERLY CHANNELING WEDNESDAY AFTERNOON
INTO WEDNESDAY NIGHT. WINDS SHIFT TO THE WEST AND NORTHWEST AND
COULD REMAIN GUSTY THURSDAY AS A COLD FRONT CROSSES, POSSIBLY
BRINGING A FEW SHOWERS AND THUNDERSTORMS.
SUB-SCA LEVEL NORTH TO NORTHWESTERLY WINDS ARE EXPECTED OVER
THE WATERS ON FRIDAY. WINDS WILL SHIFT TO OUT OF THE SOUTH ON
SATURDAY, AND COULD NEAR LOW-END SCA LEVELS WITHIN CHANNELED
SOUTHERLY FLOW SATURDAY AFTERNOON INTO SATURDAY EVENING.
TIDES/COASTAL FLOODING
TIDE LEVELS REMAIN AROUND 1 TO 1.25 FEET ABOVE NORMAL. WITH
LIGHT NORTHEAST WINDS BECOMING SOUTHERLY, TIDE LEVELS ARE LIKELY
TO REMAIN RELATIVELY STEADY AROUND 1 FOOT ABOVE ASTRONOMICAL
NORMS THROUGH THE MIDDLE OF THE WEEK. ANNAPOLIS COULD REACH
MINOR STAGE ONE OR TWO MORE TIMES THROUGH THURSDAY PRIOR TO A
COLD FRONT SHIFTING WINDS TO THE WEST. OTHER SITES COULD
APPROACH MINOR FLOOD AT TIMES, AS WELL, MAINLY LATE WEDNESDAY
NIGHT INTO EARLY THURSDAY MORNING.
LWX WATCHES/WARNINGS/ADVISORIES
DC...NONE.
MD...NONE.
VA...NONE.
WV...NONE.
MARINE...NONE.
DISCUSSION...BRO/KLW/CJL/KJP
AVIATION...KLW/CJL/KJP
MARINE...KLW/CJL/KJP
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