103
FXUS61 KLWX 171845
AFDLWX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
245 PM EDT FRI OCT 17 2025
SYNOPSIS
SURFACE HIGH PRESSURE WILL REMAIN OVERHEAD THROUGH TONIGHT
BEFORE MOVING OFFSHORE TOMORROW. A POTENT LOW PRESSURE SYSTEM
WILL PASS THROUGH THE GREAT LAKES SATURDAY NIGHT INTO EARLY
SUNDAY AND THE COLD FRONT ASSOCIATED WITH THIS SYSTEM WILL PASS
THROUGH OUR AREA LATE SUNDAY INTO SUNDAY NIGHT. HIGH PRESSURE
WILL BRIEFLY RETURN EARLY NEXT WEEK BEFORE A COUPLE REINFORCING
COLD FRONTS PASS THROUGH DURING THE MIDDLE AND LATTER PORTIONS
OF NEXT WEEK.
NEAR TERM /THROUGH TONIGHT/
A DRY NORTHWEST FLOW AHEAD OF BUILDING HIGH PRESSURE WILL
CONTINUE TO BRING SUNSHINE AND DRY CONDITIONS THROUGH THIS
AFTERNOON.
SURFACE HIGH PRESSURE WILL REMAIN OVERHEAD THROUGH TONIGHT.
LIGHT WINDS AND LOW DEWPOINTS WILL SET THE STAGE FOR RADIATIONAL
COOLING AGAIN. HOWEVER, IT WILL NOT BE AS CHILLY AS LAST NIGHT
(WARMER START, AND SOME HIGH CLOUDS MOVING IN OVERNIGHT). LOW
TEMPERATURES WILL RANGE FROM THE MID TO UPPER 30S IN THE COLDER
VALLEYS AND RURAL AREAS, TO THE UPPER 40S AND LOWER 50S IN THE
URBAN AREAS AND NEAR BAY/POTOMAC RIVER.
SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/
HIGH PRESSURE WILL MOVE OFFSHORE SATURDAY AND A RETURN
SOUTHERLY FLOW WILL DEVELOP BEHIND THE DEPARTING HIGH. THE
SOUTHERLY FLOW WILL ALLOW FOR A WARMER AFTERNOON, WITH HIGHS
RANGING FROM THE UPPER 60S TO LOWER 70S NEAR THE WATERS, TO THE
UPPER 70S AND LOWER 80S IN THE VALLEYS OF THE POTOMAC HIGHLANDS
(DOWNSLOPING FLOW).
A POTENT LOW WILL MOVE INTO THE GREAT LAKES SATURDAY NIGHT INTO
SUNDAY MORNING AND A COLD FRONT WILL APPROACH FROM THE WEST
DURING THIS TIME. A SOUTHERLY FLOW WILL INCREASE, ALLOWING FOR
MILD CONDITIONS. MOISTURE WILL BEGIN TO INCREASE CAUSING MORE
CLOUDS, BUT DRY CONDITIONS WILL MOST LIKELY PERSIST.
THE COLD FRONT WILL SLOWLY PASS THROUGH THE AREA FROM WEST TO
EAST LATER SUNDAY AFTERNOON INTO SUNDAY EVENING. SHOWERS ARE
EXPECTED TO DEVELOP WITH THE FRONTAL PASSAGE WEST OF THE BLUE
RIDGE SUNDAY AFTERNOON, AND EAST OF THE BLUE RIDGE SUNDAY NIGHT.
THE UPPER-LEVEL TROUGH AXIS IS EXPECTED TO SWING TOWARD A
NEGATIVE TILT AROUND THE TIME OF THE FRONTAL PASSAGE. THIS MEANS
FORCING WILL BE STRONG ALONG WITH A STRONG WIND FIELD ALOFT.
THEREFORE, A LINE OF GUSTY SHOWERS IS MOST LIKELY TO DEVELOP
LATE SUNDAY AFTERNOON INTO SUNDAY EVENING ALONG AND JUST AHEAD
OF THE COLD FRONT. WITH A VERY STRONG WIND FIELD ALOFT, IT IS
NOT OUT OF THE QUESTION FOR SOME OF THESE WINDS TO MIX DOWN,
CAUSING A THREAT FOR DAMAGING WIND GUSTS. HOWEVER, CONFIDENCE
IS LOW AT THIS TIME DUE TO LIMITED INSTABILITY. ADDITIONAL
SHOWERS ARE POSSIBLE OVERNIGHT BEHIND THE COLD FRONT AS THE
NEGATIVELY TILTED UPPER-LEVEL TROUGH PASSES THROUGH. SOME
GUIDANCE IS INDICATING A CLOSED UPPER-LEVEL LOW CAN DEVELOP. IF
SO, THE SHOWERS WILL BE MORE WIDESPREAD DURING THE OVERNIGHT
HOURS.
LONG TERM /MONDAY THROUGH FRIDAY/
STRONG COLD FRONT SHOULD HAVE PUSHED EAST OF THE AREA EARLY MONDAY
MORNING WITH GUSTY POST-FRONTAL NW WINDS. WEAK SFC HIGH PRESSURE
BUILDS IN BY THE END OF MONDAY. ANOTHER POTENT TROUGH/CLOSED LOW
TRAVERSES THE MID-ATLC AREA TUE NIGHT BRINGING LIGHT RAIN SHOWERS
TUESDAY AFTERNOON AND EVENING WITH MOUNTAIN RAIN SHOWERS
CONTINUING IN FAVORABLE UPSLOPE FLOW AND EVEN PERHAPS A
SNOWFLAKE MIXED IN AT TIMES OVER THE HIGHEST ELEVATIONS AS 850
MB TEMPS DROP BETWEEN 0C AND +2C. BROAD TROUGH PATTERN PERSISTS
FOR THE SECOND HALF OF NEXT WEEK KEEPING NEAR NORMAL TO BELOW
NORMAL TEMPERATURES.
AVIATION /18Z FRIDAY THROUGH WEDNESDAY/
VFR CONDITIONS ARE EXPECTED THROUGH SATURDAY. NORTHWEST WINDS
THIS AFTERNOON WILL BECOME LIGHT OR CALM TONIGHT BEFORE TURNING
SOUTHERLY FOR SATURDAY. INCREASED MOISTURE WITH SOUTHERLY WINDS
IS EXPECTED SATURDAY NIGHT, BUT VFR CONDITIONS ARE MOST LIKELY
TO PERSIST.
STRONGER SOUTHERLY WINDS ARE EXPECTED AHEAD OF A COLD FRONT
SUNDAY WITH GUSTS AROUND 25 TO 30 KNOTS MOST LIKELY. SHOWERS ARE
EXPECTED WITH THE COLD FRONT LATER SUNDAY AFTERNOON THROUGH
MOST OF SUNDAY NIGHT. A WIND SHIFT TO THE WEST AND NORTHWEST IS
EXPECTED BEHIND THE COLD FRONT LATE SUNDAY NIGHT. SUBVFR
CONDITIONS ARE POSSIBLE IN SHOWERS SUNDAY NIGHT.
GUSTY POST-FRONTAL NW WINDS MONDAY, WHICH DIMINISH BY MONDAY
EVENING. FAIR WEATHER ON TUESDAY.
MARINE
WINDS WILL CONTINUE TO DIMINISH OVER THE WATERS THROUGH THIS
EVENING. SOUTHERLY WINDS WILL DEVELOP SATURDAY, BUT WIND SPEEDS
SHOULD REMAIN BELOW SCA CRITERIA. SOUTHERLY WINDS MAY CHANNEL UP
THE BAY AND LOWER TIDAL POTOMAC SATURDAY NIGHT, AND A SMALL
CRAFT ADVISORY MAY BE NEEDED FOR THOSE AREAS. STRONGER SOUTHERLY
WINDS ARE EXPECTED SUNDAY INTO SUNDAY EVENING AHEAD OF A COLD
FRONT. A SMALL CRAFT ADVISORY WILL BE NEEDED. WINDS MAY EVEN
APPROACH GALE-FORCE, BUT CONFIDENCE IS LOWER DUE TO THE
RELATIVELY COOLER WATERS. WINDS WILL TURN TO THE NORTHWEST
BEHIND A COLD FRONT LATE SUNDAY NIGHT, AND AN SCA WILL BE
NEEDED.
SHOWERS WILL INCREASE IN COVERAGE, ESPECIALLY SUNDAY NIGHT. A
LINE OF HEAVIER SHOWERS ALONG THE COLD FRONT MAY CAUSE GUSTY
WINDS, AND SPECIAL MARINE WARNINGS MAY BE WARRANTED. THIS IS
MOST LIKELY TO OCCUR LATE SUNDAY EVENING.
TIDES/COASTAL FLOODING
HIGHER ANOMALIES IN THE SOUTHERN PORTION OF THE CHESAPEAKE BAY
WILL SURGE NORTHWARD TONIGHT, AND THIS MAY CAUSE MINOR TIDAL
FLOODING FOR SENSITIVE AREAS (ANNAPOLIS) WITH THE HIGH TIDE
CYCLE TONIGHT.
A SOUTHERLY FLOW WILL DEVELOP SATURDAY AND STRENGTHEN SUNDAY.
THIS WILL CONTINUE TO INCREASE TIDAL ANOMALIES ALONG WITH THE
FACT THAT A NEW MOON IS APPROACHING ON THE 21ST. MINOR TIDAL
FLOODING IS EXPECTED FOR SENSITIVE AREAS SATURDAY INTO SATURDAY
NIGHT, AND FOR MOST AREAS SUNDAY INTO SUNDAY NIGHT. THERE IS THE
POTENTIAL FOR MODERATE TIDAL FLOODING AROUND ANNAPOLIS WITH THE
HIGH TIDE CYCLES SUNDAY AFTERNOON AND SUNDAY NIGHT. WILL
CONTINUE TO MONITOR.
LWX WATCHES/WARNINGS/ADVISORIES
DC...NONE.
MD...NONE.
VA...NONE.
WV...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 4 PM EDT THIS AFTERNOON FOR
ANZ532>534-537-540-541-543.
SYNOPSIS...BJL/CS
NEAR TERM...BJL/CS
SHORT TERM...BJL/CS
LONG TERM...LFR
AVIATION...BJL/CS/LFR
MARINE...BJL/CS/LFR
TIDES/COASTAL FLOODING...BJL
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