556
FXUS61 KLWX 091936
AFDLWX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
336 PM EDT TUE SEP 9 2025
SYNOPSIS
HIGH PRESSURE WILL BUILD TO THE NORTH THROUGH THE MIDDLE OF THE
WEEK. MEANWHILE, A WEAK WAVE OF LOW PRESSURE SLIDES UP THE EAST
COAST. A DRY COLD FRONT WILL CROSS THE REGION THURSDAY,
FOLLOWED BY ANOTHER CANADIAN HIGH PRESSURE SYSTEM AT THE END OF
THE WEEK INTO THIS WEEKEND.
NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/
THE CURRENT FORECAST REMAINS ON TRACK WITH CLOUD COVER
THICKENING FROM EAST TO WEST IN RESPONSE TO A FRONTAL ZONE OFF
THE DELMARVA TO CAROLINA COAST. THE CURRENT VISIBLE SATELLITE
IMAGERY SHOWS THE THICKEST CLOUD COVER OVER THE EASTERN SHORE
WITH SOME SCATTERED CUMULUS EDGING WESTWARD TO AROUND THE I-95
CORRIDOR. HIGH PRESSURE TO THE NORTH HAS MAINTAINED A STEADY
NORTHERLY WIND WHICH HAS KEPT HUMIDITY LEVELS LOW FOR EARLY
SEPTEMBER STANDARDS. NORTH TO NORTHEASTERLY WINDS HAVE GUSTED TO
15 TO 20 MPH AT TIMES GIVEN ENHANCED BOUNDARY LAYER MIXING. TODAY'S
HIGHS WILL END UP IN THE MID/UPPER 70S, WITH MOUNTAINS ONCE
AGAIN IN THE 60S. HAVE KEPT DEW POINTS A BIT LOWER THAN
GUIDANCE, PARTICULARLY WEST OF THE BLUE RIDGE MOUNTAINS.
MODEL GUIDANCE REMAINS IN DECENT AGREEMENT REGARDING THE
DEVELOPMENT OF THE AREA OF LOW PRESSURE OFF THE CAROLINAS ALONG
THE WAVY COASTAL BOUNDARY. THIS WILL INCREASE SHOWER CHANCES
EAST OF I-95 TONIGHT. HOWEVER, GIVEN THE DRY AIR MASS IN PLACE,
MUCH OF THE INITIAL ACTIVITY MAY BE LOST TO EVAPORATION. FOR
TEMPERATURES, IT WILL BE AROUND 5 DEGREES MILDER THAN THE
PREVIOUS NIGHT, PARTICULARLY ALONG AND EAST OF I-95 GIVEN
INCREASED CLOUD COVER.
SHORT TERM /6 AM WEDNESDAY MORNING THROUGH THURSDAY NIGHT/
SPARSE SHOWER CHANCES PERSIST INTO WEDNESDAY MORNING ALONG THE
CHESAPEAKE BAY SHORES. HOWEVER, IT IS MORE LIKELY THAT THESE
SHOWERS REMAIN OVER THE EASTERN SHORE AND POINTS EASTWARD. CLOUD
COVER REMAINS OVER AREAS EAST OF THE BLUE RIDGE, BUT THESE WILL
EDGE EASTWARD IN TIME. SOME LATE DAY SUNSHINE IS POSSIBLE
ACROSS THE I-95 CORRIDOR. HIGH TEMPERATURES ARE FORECAST TO
REMAIN IN THE LOW/MID 70S (60S IN THE MOUNTAINS). OVERNIGHT LOWS
DROP INTO THE 50S, WITH SOME MID/UPPER 40S POSSIBLE OVER THE
CENTRAL SHENANDOAH VALLEY BACK INTO THE POTOMAC HIGHLANDS.
HIGH PRESSURE RETURNS ON THURSDAY WITH MOSTLY SUNNY SKIES AND
TEMPERATURES ACTUALLY RETURNING CLOSER TO AVERAGE FOR THIS TIME
OF YEAR, WITH HIGHS IN THE 70S TO LOW 80S.
LONG TERM /FRIDAY THROUGH TUESDAY/
ANOTHER AREA OF STRONG HIGH PRESSURE WILL DESCEND FROM CANADA INTO
NEW ENGLAND FRIDAY AND SATURDAY BENEATH LONGWAVE TROUGHING ALOFT. BY
SUNDAY, THE HIGH WILL BE SQUEEZED BETWEEN A LOW PRESSURE SYSTEM
APPROACHING THE GREAT LAKES AND A FRONTAL ZONE/POSSIBLE LOW OFF THE
SOUTHEAST COAST. MODELS DIVERGE ALOFT WITH HOW TO HANDLE A
TROUGH/CLOSED LOW DESCENDING SOUTHWARD FROM HUDSON BAY HEADING INTO
EARLY NEXT WEEK. WHILE THIS COULD LEND SOME UNCERTAINTY TO THE
FORECAST, THE APPROACHING FRONTAL ZONE APPEARS TO BE MOISTURE
STARVED. THEREFORE, DRY CONDITIONS AND SIMILAR TEMPERATURES (NEAR TO
SLIGHTLY BELOW NORMAL) PERSIST FOR THE FRIDAY THROUGH MONDAY
PERIOD.
AVIATION /20Z TUESDAY THROUGH SUNDAY/
NORTH TO NORTHEASTERLY GUSTS UP TO 15 TO 20 KNOTS WILL CONTINUE
THROUGH THE AFTERNOON TO EARLY EVENING. THIS IS IN RESPONSE TO
THE TIGHTENING GRADIENTS BETWEEN HIGH PRESSURE TO THE NORTH AND
LOW PRESSURE PASSING BY TO THE SOUTH AND EAST.
SOME LOW CLOUDS WILL TRY TO PUSH AS FAR EAST AS THE BLUE RIDGE
OVERNIGHT INTO WEDNESDAY MORNING. SUB-VFR CONDITIONS ARE
POSSIBLE DURING THIS TIME AT IAD AND CHO, BUT SEEM MOST LIKELY
AT DCA, BWI, AND MTN.
WINDS RETURN TO NORTHERLY LATER WEDNESDAY AS THE COASTAL SYSTEM
PUSHES FURTHER OFFSHORE. SIGNIFICANT WEATHER IS UNLIKELY
THROUGH SATURDAY UNDER HIGH PRESSURE.
MARINE
THE COMBINATION OF CANADIAN HIGH PRESSURE TO THE NORTH AND LOW
PRESSURE MOVING ALONG A STALLED FRONTAL ZONE TO THE SOUTH WILL
AID IN ENHANCED NORTH TO NORTHEASTERLY WINDS THROUGH MID-WEEK.
EXPECT GUSTS UP TO AROUND 20 TO 25 KNOTS, PARTICULARLY OVER THE
MORE OPEN WATERS OF THE CHESAPEAKE BAY. SMALL CRAFT ADVISORIES
CONTINUE THROUGH MUCH OF THE DAY ON WEDNESDAY ACROSS VAST
PORTIONS OF THE CHESAPEAKE BAY INTO THE LOWER TIDAL POTOMAC. FOR
THE UPPER/MIDDLE TIDAL POTOMAC, WIND GUSTS WILL LIKELY BE RIGHT
ALONG THE ADVISORY THRESHOLD. GIVEN LATE MORNING OBSERVATIONS,
OPTED TO PLACE SMALL CRAFT ADVISORIES ACROSS THESE WATERS
THROUGH EARLY THIS EVENING.
WINDS FINALLY START TO DIMINISH WEDNESDAY EVENING AS THE
AFOREMENTIONED AREA OF LOW PRESSURE PUSHES AWAY FROM THE
REGION. SUB-SCA WINDS ARE EXPECTED TO CONTINUE THROUGH THURSDAY
AS WELL.
NORTHEAST TO EAST WINDS PREVAIL FRIDAY AND SATURDAY DUE TO HIGH
PRESSURE TO THE NORTH. WINDS ARE FORECAST TO REMAIN BELOW ADVISORY
LEVELS AT THIS TIME, BUT IT'S WORTH MONITORING THE POTENTIAL FOR LOW
PRESSURE TO FORM OFF THE SOUTHEAST COAST, WHICH COULD INCREASE THE
PRESSURE GRADIENT AND THUS WINDS.
TIDES/COASTAL FLOODING
DUE TO THE COMBINATION OF WINDS NOT QUITE ALIGNED TO PUSH WATER
SOUTH AND OUT OF THE BAY, AND THE RECENT FULL MOON, TIDES WILL BE
SOMEWHAT ELEVATED IN THE COMING DAYS. NE WINDS DURING THE MIDDLE OF
THE WEEK MAY ASSIST IN LOCKING IN HIGHER WATER LEVELS AND PUSHING
THE WATER TOWARD THE WESTERN SHORE. ANNAPOLIS AND DAHLGREN ARE
MOST LIKELY TO REACH MINOR FLOOD STAGE, BUT SOME OTHER LOCATIONS
MAY BE CLOSE. THE FIRST OPPORTUNITY FOR FLOODING WILL BE LATE
THIS AFTERNOON AND EVENING, AND THEN COULD OCCASIONALLY BE AN
ISSUE THROUGH THE END OF THE WEEK WITH NO REAL PATTERN CHANGE IN
SIGHT.
LWX WATCHES/WARNINGS/ADVISORIES
DC...NONE.
MD...SMALL CRAFT ADVISORY UNTIL 2 PM EDT WEDNESDAY FOR MDZ008.
COASTAL FLOOD ADVISORY UNTIL 7 PM EDT THIS EVENING FOR MDZ016.
VA...COASTAL FLOOD ADVISORY UNTIL 7 PM EDT THIS EVENING FOR VAZ057.
WV...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 2 PM EDT WEDNESDAY FOR ANZ530>532-
538>540.
SMALL CRAFT ADVISORY UNTIL 5 PM EDT WEDNESDAY FOR ANZ533-534-
537-541>543.
SMALL CRAFT ADVISORY UNTIL 8 PM EDT WEDNESDAY FOR ANZ535-536.
SYNOPSIS...BRO/CJL
NEAR TERM...BRO/CJL
SHORT TERM...CJL
LONG TERM...KJP
AVIATION...BRO/CJL/KJP
MARINE...BRO/CJL/KJP
TIDES/COASTAL FLOODING...BRO/CJL
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