836
FXUS61 KLWX 300108
AFDLWX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
908 PM EDT TUE SEP 29 2026
WHAT HAS CHANGED
PATCHY FOG HAS BEEN ADDED TO THE FORECAST FOR MANY AREA TONIGHT.
IF SKIES CLEAR OUT, DENSE FOG COULD BE POSSIBLE IN SOME
LOCATIONS.
KEY MESSAGES
- 1) TRANQUIL WEATHER IS EXPECTED THROUGH THURSDAY WITH
CLIMBING TEMPERATURES.
- 2) A STALLING COLD FRONT AND WAVE OF LOW PRESSURE MAY AFFECT
THE AREA THIS WEEKEND.
- 3) HIGH PRESSURE LIKELY RETURNS EARLY NEXT WEEK.
DISCUSSION
KEY MESSAGE 1...TRANQUIL WEATHER IS EXPECTED THROUGH THURSDAY
WITH CLIMBING TEMPERATURES.
UPPER LEVEL RIDGING SLOWLY BUILDS OVERHEAD BEGINNING TONIGHT
WITH SURFACE HIGH PRESSURE REMAINING OVERHEAD THROUGH THURSDAY.
AS OF 9 PM, SATELLITE IMAGERY SHOWS A STRATOCUMULUS DECK THAT IS
GRADUALLY ERODING. WINDS ARE EXPECTED TO GO CALM IN MOST
LOCATIONS TONIGHT AS HIGH PRESSURE BUILDS OVERHEAD. WITH
DEWPOINTS GENERALLY IN THE UPPER 50S TO LOW 60S, TEMPERATURES
WON'T HAVE TO FALL FAR TO REACH SATURATION. PATCHY FOG IS
EXPECTED TO FORM OVERNIGHT IN LOCATIONS THAT CLEAR OUT AND
RADIATE, WHILE LOCATIONS THAT HANG ONTO THICKER CLOUD COVER
THROUGH THE NIGHT LIKELY WON'T HAVE FOG FORM. SOME OF THE FOG
COULD BE LOCALLY DENSE, ESPECIALLY IN DEEPER VALLEYS TO THE WEST
OF THE BLUE RIDGE. ANY FOG THAT DOES FORM WILL QUICKLY DISSIPATE
AFTER SUNRISE TOMORROW MORNING.
WITH UPPER LEVEL RIDGING AND SURFACE HIGH PRESSURE OVERHEAD, DRY
CONDITIONS AND WARMING TEMPERATURES ARE EXPECTED THROUGH THE END OF
THE WEEK. HIGH TEMPERATURES WEDNESDAY WILL RISE INTO THE UPPER
70S AND LOWER 80S, WITH HIGHS BY FRIDAY RISING TO NEAR 90 FOR
PORTIONS OF THE AREA. ON FRIDAY, SURFACE HIGH PRESSURE SHIFTS
OFFSHORE AS A COLD FRONT APPROACHES FROM THE NORTHWEST.
DEPENDING ON THE PROGRESSION OF THIS FRONT, SHOWERS AND
POTENTIALLY A THUNDERSTORM OR TWO COULD BE POSSIBLE BY LATER
FRIDAY AFTERNOON INTO FRIDAY NIGHT.
KEY MESSAGE 2...A STALLING COLD FRONT AND WAVE OF LOW PRESSURE
MAY AFFECT THE AREA THIS WEEKEND.
UPPER TROUGHING SHEARS OUT TOWARD THE GREAT LAKES, EVENTUALLY
BECOMING ABSORBED IN A LARGER CYCLONIC GYRE NEAR HUDSON BAY THIS
WEEKEND. AT THE SURFACE, THIS PATTERN SENDS A COLD FRONT SOUTHWARD
INTO VIRGINIA. THERE IS SOME LINGERING UNCERTAINTY AS TO WHERE THE
FRONT STALLS, WITH A SHARP TEMPERATURE GRADIENT ACROSS THE FRONTAL
ZONE (60S ON THE NORTH/COOL SIDE, 80S ON THE SOUTH/WARM SIDE). THE
TEMPERATURE FORECAST FOR SATURDAY MAY BE SUBJECT TO LARGE CHANGES OF
10 OR MORE DEGREES AS A RESULT, WITH THE CURRENT FORECAST SPLITTING
THE DIFFERENCE AND CALLING FOR WIDESPREAD 60S AND 70S GIVEN AT LEAST
SOME BROAD CONSENSUS THAT THE FRONT ENDS UP TO THE SOUTH PLACING THE
MID-ATLANTIC ON ITS COOLER AND CLOUDIER SIDE. SHOWER ACTIVITY MAY
ACCOMPANY THE STALLING FRONT, WITH UNCERTAINTY IN COVERAGE (THOUGH
ANYTHING SEVERE OR PARTICULARLY HEAVY SEEMS UNLIKELY AT THIS POINT).
A WAVE OF LOW PRESSURE, INFUSED WITH TROPICAL MOISTURE FROM THE
REMNANTS OF MULTIPLE EAST PACIFIC SYSTEMS, TREKS TOWARD THE OH/TN
VALLEYS SATURDAY INTO SATURDAY NIGHT. THE TRACK OF THE LOW BEYOND
THIS POINT WILL DEPEND ON (1) WHERE EXACTLY THE STALLED FRONT IS,
AND (2) THE STRENGTH OF A TRANSIENT BLOCKING HIGH PRESSURE TO THE
NORTH. RAIN OR SHOWERS BECOME INCREASINGLY LIKELY FOR MUCH OF THE
REGION SATURDAY NIGHT INTO SUNDAY, WITH A SOAKING RAIN POSSIBLE IF
THE WAVE OF LOW PRESSURE IS A BIT MORE ORGANIZED/CLOSER TO THE AREA.
KEY MESSAGE 3...HIGH PRESSURE LIKELY RETURNS EARLY NEXT WEEK.
FOLLOWING THE WEEKEND SYSTEM, A LARGE AREA OF HIGH PRESSURE WILL
LIKELY BUILD FROM THE UPPER MIDWEST AND GREAT LAKES TO THE NORTHEAST
AND MID-ATLANTIC EARLY NEXT WEEK. THIS SETS THE STAGE FOR MUCH DRIER
WEATHER AND BELOW NORMAL TEMPERATURES FOR THE FIRST HALF OF NEXT
WEEK. DAYTIME HIGHS ON MONDAY AND TUESDAY LIKELY STAY IN THE 60S
(50S IN THE MOUNTAINS), WITH OVERNIGHT LOWS IN THE 40S TO NEAR 50
(30S IN THE MOUNTAINS AND SHELTERED VALLEYS WEST OF THE BLUE RIDGE
WITH PERHAPS SOME FROST POTENTIAL IN THE COLDEST SPOTS).
AVIATION /00Z WEDNESDAY THROUGH SUNDAY/
LIGHT WINDS AND PREVAILING VFR CONDITIONS ARE EXPECTED AT THE
TERMINALS TONIGHT, ALTHOUGH SOME FOG COULD FORM CLOSER TO
DAYBREAK. MRB AND CHO WILL BE THE MOST LIKELY TO SEE FOG,
FOLLOWED BY IAD, BUT SOME PATCHY FOG CAN'T BE RULED OUT
ANYWHERE. ANY FOG THAT DOES FORM SHOULD DISSIPATE SHORTLY AFTER
SUNRISE.
SURFACE HIGH PRESSURE REMAINS OVERHEAD WEDNESDAY AND THURSDAY WITH
VFR CONDITIONS EXPECTED BOTH DAYS. WINDS SHIFT TO SOUTHERLY ON
WEDNESDAY, BLOWING 10 KNOTS OR LESS. WINDS REMAIN LIGHT OUT OF THE
SOUTH/SOUTHWEST ON THURSDAY.
LOWER CIGS ARE POSSIBLE IN THE WAKE OF A STALLING COLD FRONT
SATURDAY. RAIN SHOWERS BECOME INCREASINGLY LIKELY SATURDAY NIGHT
INTO SUNDAY WITH SUB-VFR CIGS/VSBYS POSSIBLE AT TIMES. THE WIND
FORECAST IS SOMEWHAT UNCERTAIN AND CONTINGENT ON WHERE EXACTLY A
FRONT STALLS SATURDAY, AND WHERE A WAVE OF LOW PRESSURE TRACKS
SUNDAY, BUT GENERALLY NORTH TO EAST FLOW IS EXPECTED. SOME GUSTS OF
15 TO 20 KNOTS ARE PLAUSIBLE EACH DAY.
MARINE
LIGHT AND VARIABLE WINDS ARE EXPECTED OVER THE WATERS TONIGHT.
WINDS SHIFT TO SOUTHERLY WEDNESDAY AND REMAIN OUT OF THE SOUTH
ON THURSDAY. WITH SOUTHERLY CHANNELING, WINDS INCREASE OVER THE
WATERS ALTHOUGH ARE EXPECTED TO REMAIN BELOW SCA CRITERIA. THAT
BEING SAID, A BRIEF PERIOD OF NEAR SCA CRITERIA WINDS ARE
POSSIBLE ON THURSDAY AFTERNOON AND CAN LIKELY BE COVERED WITH AN
MWS.
NORTH TO NORTHEAST WINDS MAY GUST TO AROUND 20 KNOTS IN THE WAKE OF
A STALLING FRONT SATURDAY, THOUGH THE WIND FORECAST IS A BIT
UNCERTAIN AND DEPENDS ON EXACTLY WHERE THE FRONT STALLS. A WAVE OF
LOW PRESSURE PASSES BY ON SUNDAY, WHICH DEPENDING ON ITS EXACT TRACK
AND STRENGTH COULD RESULT IN ADDITIONAL GUSTINESS AND SCAS. RAIN
SHOWERS ARE MOST LIKELY SATURDAY NIGHT INTO SUNDAY; THUNDER
POTENTIAL SEEMS VERY LOW, BUT NOT ZERO DURING THIS TIME.
TIDES/COASTAL FLOODING
SOME UNCERTAINTY EXISTS FOR THE REMAINDER OF THE WEEK AS TIDE
LEVELS REMAIN ELEVATED. COASTAL FLOOD ADVISORIES HAVE BEEN
ISSUED FOR ANNAPOLIS AND HAVRE DE GRACE WITH TIDAL ANOMALIES
FORECAST TO REACH MINOR FLOOD STAGE. ANY SUBTLE SHIFTS UPWARD
COULD RESULT IN ADDITIONAL MINOR FLOODING, PARTICULARLY AT
DAHLGREN, ALEXANDRIA, AND BALTIMORE WHERE HIGH TIDE WILL NEAR
MINOR FLOOD STAGE. MINOR FLOODING WILL OCCUR AS SOON AS THIS
EVENING'S HIGH TIDE. EVENING TIDES WOULD BE FAVORED GOING
FORWARD AS WELL SINCE THEY ARE ASTRONOMICALLY HIGHER.
LWX WATCHES/WARNINGS/ADVISORIES
DC...NONE.
MD...COASTAL FLOOD ADVISORY UNTIL 11 PM EDT THIS EVENING FOR MDZ014.
COASTAL FLOOD ADVISORY UNTIL 2 AM EDT WEDNESDAY FOR MDZ508.
VA...NONE.
WV...NONE.
MARINE...NONE.
DISCUSSION...ADS/AVS/DHOF/KJP
AVIATION...AVS/DHOF/KJP
MARINE...AVS/DHOF/KJP
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