092
FXUS61 KLWX 201914
AFDLWX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
314 PM EDT SUN SEP 20 2026
WHAT HAS CHANGED
NOTHING.
KEY MESSAGES
- 1) NUMEROUS SHOWERS EXPECTED THROUGH THIS EVENING. TURNING
MUCH COOLER MONDAY AND THROUGH THE REST OF THE WEEK.
- 2) COOL & WET CONDITIONS PERSIST THROUGH THE END OF THE WEEK,
WITH DRIER CONDITIONS HEADING INTO THE WEEKEND.
DISCUSSION
KEY MESSAGE 1...NUMEROUS SHOWERS EXPECTED THROUGH THIS EVENING. TURNING
MUCH COOLER MONDAY AND THROUGH THE REST OF THE WEEK.
EXTENSIVE CLOUDINESS HAS LIMITED INSTABILITY ALL DAY WITH VIS
IMAGERY AND NUCAPS DATA SHOWING ONLY SOUTHERN MD HAVING RECEIVED
ENOUGH SUNSHINE FOR THUNDERSTORMS TO POTENTIALLY DEVELOP LATER
THIS AFTERNOON OR EVENING. OTHERWISE, A WEAK AREA OF LOW
PRESSURE WILL PASS THROUGH THE AREA EARLY THIS EVENING AND
SHOULD BRING A ROUND OF LIGHT SHOWERS TO MOST AREAS THROUGH MID
EVENING, EXCEPT IN THE SOUTH. THE FRONT WILL SINK SOUTH
OVERNIGHT WITH SHOWERS ENDING, WITH CLOUDS LOWERING.
MORE SHOWERS WILL ARRIVE IN THE WEST TOWARD DAYBREAK AS THE NEXT
SHORTWAVE-TROUGH AND WEAK AREA OF LOW PRESSURE APPROACHES THE
AREA. THESE SHOWERS WILL SLOWLY PROGRESS EAST DURING THE
AFTERNOON MONDAY. THE PERIOD OF HEAVIEST RAINFALL LOOKS TO BE
MONDAY NIGHT/EARLY TUESDAY WHEN ONSHORE FLOW/MOISTURE ADVECTION
IS STRONGEST COMBINES WITH A WEAK LOW TO MID-LEVEL LOW PRESSURE.
HIGH PRESSURE THEN BUILDS SOUTH FROM THE NORTHEAST TUE SETTING
UP A STRONG COLD AIR DAMMING EVENT SUPPORTING WELL BELOW NORMAL
TEMPERATURES AND CLOUDY CONDITIONS.
KEY MESSAGE 2...COOL & WET CONDITIONS PERSIST THROUGH THE END
OF THE WEEK, WITH DRIER CONDITIONS HEADING INTO THE WEEKEND.
INTERMITTENT SHOWERS REMAIN POSSIBLE MID-TO-LATE WEEK AS A
LINGERING FRONTAL BOUNDARY SAGS TO THE SOUTH. ADDITIONALLY, A
STRONG COASTAL LOW BEGINS TO TRACK NORTH CLOSE TO THE MARYLAND
COAST THURSDAY AND INTO FRIDAY, WHICH WILL BRING GUSTY
CONDITIONS TO THE REGION. THIS STRONG ONSHORE FLOW COULD BRING
MINOR COASTAL FLOODING TO SITES ALONG THE CHESAPEAKE BAY. SEE
THE COASTAL FLOODING SECTION BELOW FOR MORE INFORMATION.
AS THIS COASTAL LOW TRACKS TO THE NORTH, DRY MID-LEVEL AIR FROM THE
UPPER MIDWEST MOVES IN OVERHEAD. THIS WILL CREATE SOMEWHAT DRIER
CONDITIONS HEADING INTO THE WEEKEND, ALTHOUGH THERE IS A BIT OF
MODEL DISCREPANCY ON HOW SLOW THE COASTAL LOW WILL BE MOVING OUT OF
THE AREA. WINDS COULD STAY ELEVATED UNTIL THIS SYSTEM IS WELL NORTH
OF THE MID-ATLANTIC. TEMPERATURES STAY SLIGHTLY COOLER-THAN-AVERAGE
DURING THIS TIME, ALTHOUGH GRADUALLY INCREASE NEAR THE END OF THE
WEEK AS ANY LINGERING SHORTWAVE DISTURBANCES TRACK OFFSHORE.
AVIATION /18Z SUNDAY THROUGH FRIDAY/
A COLD FRONT WILL DROP SOUTH THIS EVENING SUPPORTING NUMEROUS
SHOWERS. WINDS SHIFT TO THE NORTH TONIGHT WITH IFR CONDITIONS
DEVELOPING. IFR CIGS PERSIST THROUGH MID WEEK.
INTERMITTENT SUB-VFR CONDITIONS LIKELY CONTINUE THROUGH THURSDAY AS
ADDITIONAL SHOWERS MOVE THROUGH THE MID-ATLANTIC, REDUCING CIGS AND
VSBYS. CONDITIONS POTENTIALLY IMPROVE SOMEWHAT ON FRIDAY AS A TROUGH
MOVES NORTH OUT OF THE REGION. GUSTY WINDS REMAIN A POSSIBILITY
THROUGH THE END OF THE WEEK DUE TO ONSHORE FLOW, WITH GUSTS BETWEEN
15-25 KNOTS POSSIBLE. WINDS FLOW NORTH TO NORTHEASTERLY.
MARINE
WINDS HAVE RELAXED A BIT THIS AFTERNOON, BUT ARE EXPECTED TO
STRENGTHEN MONDAY NIGHT THROUGH EARLY THURSDAY. ADDITIONAL SCAS
WILL BE NEEDED.
WIND GUSTS WILL BE STRONGEST ON THURSDAY OVER THE BAY AS A COASTAL
STORM TRACKS TO THE NORTH OFF THE EAST COAST. SUSTAINED WINDS
BETWEEN 20-25 KNOTS ARE POSSIBLE WITH AS WINDS FLOW NORTHEASTERLY.
WINDS STAY ELEVATED ON FRIDAY, FLOWING DUE NORTH. ON AND OFF SHOWERS
ARE POSSIBLE OVER THE WATERS AS MULTIPLE SHORTWAVE DISTURBANCES MOVE
THROUGH.
TIDES/COASTAL FLOODING
WATER LEVELS REMAIN ELEVATED AS ONSHORE FLOW HAS DEVELOPED.
STRONGER NNE WINDS MONDAY AFTERNOON WILL PUSH THE WATER SOUTH
INTO THE MOUTH OF CHESAPEAKE BAY. THIS EXCESS WATER IS EXPECTED
TO SLOSH BACK MID WEEK RESULTING IN WIDESPREAD MINOR COASTAL
FLOODING, PERHAPS MODERATE AT ANNAPOLIS.
LWX WATCHES/WARNINGS/ADVISORIES
DC...NONE.
MD...COASTAL FLOOD ADVISORY UNTIL 6 AM EDT MONDAY FOR MDZ014.
VA...NONE.
WV...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 6 AM TO NOON EDT MONDAY FOR
ANZ531>534-539>541-543.
DISCUSSION...LFR/SRT
AVIATION...LFR/SRT
MARINE...LFR/SRT
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