840
FXUS61 KLWX 152011
AFDLWX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
311 PM EST FRI NOV 15 2024
SYNOPSIS
LOW PRESSURE HAS MOVED OFFSHORE WHILE HIGH PRESSURE BUILDS IN THIS
WEEKEND. THIS ALLOW FOR MODERATING TEMPERATURES AND DRY
CONDITIONS. PRECIPITATION CHANCES RETURN WITH A STRONG COLD
FRONT AND AREA OF LOW PRESSURE DURING THE MIDDLE TO LATTER HALF
OF NEXT WEEK.
NEAR TERM /THROUGH TONIGHT/
THE COMPACT UPPER LOW FROM EARLIER HAS SETTLED OFFSHORE OF THE
OUTER BANKS OF NORTH CAROLINA. IN ITS WAKE, ENHANCED MOISTURE
LINGERS OVER THE MID-ATLANTIC REGION WHICH HAS MAINTAINED LOW
CLOUDS ACROSS MOST AREAS. THE CURRENT EXCEPTION IS TOWARD THE
I-64 CORRIDOR WHERE GOES-16 VISIBLE IMAGERY SHOWS PLENTY OF
BREAKS IN THE CLOUDS. THIS HAS CONSEQUENTLY BOOSTED TEMPERATURES
INTO THE LOW 60S, WHILE MAINLY LOW/MID 50S CAN BE FOUND
ELSEWHERE (MID/UPPER 40S FOR MOUNTAIN LOCATIONS). WHILE MOST OF
THE FORECAST AREA HAS DRIED OUT, ISOLATED TO SCATTERED SHOWERS
WILL PERSIST ALONG THE ALLEGHENIES.
EXPECT A GRADUAL REDUCTION IN OVERALL CLOUD COVER THROUGH THE
NIGHT GIVEN INCREASING SUBSIDENCE. A STEADY NORTHWESTERLY
BREEZE CONTINUES OVERNIGHT WITH LOW TEMPERATURES HOLDING STEADY
IN THE 40S. SOME MID/UPPER 30S ARE POSSIBLE ACROSS THE CENTRAL
SHENANDOAH VALLEY BACK INTO THE POTOMAC HIGHLANDS. ISOLATED
SHOWERS DO PERSIST ALONG THE ALLEGHENY FRONT WITH ONLY LIGHT
AMOUNTS EXPECTED.
SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/
AS THE UPPER LOW PUSHES FURTHER OFF THE COAST, A BROAD RIDGE
INITIALLY OVER THE MISSISSIPPI RIVER VALLEY MAKES ITS WAY TOWARD
THE EASTERN SEABOARD THIS WEEKEND. INCREASING SUBSIDENCE IN THE
COLUMN WILL FAVOR MORE SUNSHINE AND AN UPTICK IN TEMPERATURES.
ASIDE FROM THE MOUNTAINS WHICH STAY IN THE 40S TO MID 50S,
EXPECT SOME POCKETS OF LOW 60S ELSEWHERE. THIS DOES COME WITH A
ROUND OF BREEZY NORTHWESTERLY WINDS. GIVEN DEEP LOW PRESSURE
NEAR NOVA SCOTIA COUPLED WITH HIGH PRESSURE OVER THE EASTERN
U.S., GRADIENTS REMAIN RELATIVELY TIGHT. THIS WILL SUPPORT LATE
MORNING TO AFTERNOON GUSTS UP TO AROUND 25 TO 30 MPH. WINDS
SHOULD DIMINISH IN STRENGTH AFTER DARK AS VERTICAL MIXING
WEAKENS. HIGH PRESSURE APPROACHING FROM THE WEST WILL SUPPORT A
SEASONABLY CHILLY NIGHT AS LOWS FALL INTO THE 30S, WITH A FEW
LOW 40S IN THE I-95 URBAN SPRAWL.
FOR SUNDAY, MOUNTAIN LOCATIONS SHOULD SEE THE BIGGEST WARM UP AS
HIGHS RETURN INTO THE 50S. THE REST OF THE AREA SEES
TEMPERATURES IN THE LOW 60S WITH A FEW MID 60S OVER THE
ALLEGHENY MOUNTAIN VALLEYS. THE FORECAST CALLS FOR INCREASING
CLOUDS THROUGHOUT THE DAY AHEAD OF A NORTHERN STREAM TROUGH
TRACKING ACROSS SOUTHERN ONTARIO. THE ASSOCIATED COLD FRONT IS
SET TO REACH THE MID-ATLANTIC REGION BY LATE SUNDAY NIGHT. ADDED
CLOUD COVER DOES KEEP TEMPERATURES A BIT MILDER AT NIGHT.
LONG TERM /MONDAY THROUGH FRIDAY/
MONDAY AND TUESDAY STILL LOOK DRY ACROSS THE REGION AS A STRONG
UPPER RIDGE BUILDS OVERHEAD. A WEAK PIECE OF UPPER-LEVEL ENERGY
RIDING ALONG THE PERIPHERY OF THIS RIDGE WILL LIKELY BRING SOME MID
TO UPPER LEVEL CLOUDINESS AT TIMES, BUT STILL EXPECT MORE SUN THAN
CLOUDS ON BOTH DAYS WITH HIGHS IN THE MID 60S.
THE REST OF NEXT WEEK STILL HAS A GREAT DEAL OF UNCERTAINTY IN
REGARDS TO HOW THINGS UNFOLD. THERE ARE 2 KEY PLAYERS TO WATCH FOR
THE MID-LATE WEEK EVENT, BOTH OF WHICH ARE JUST STARTING TO MOVE INTO
AREAS WHERE THERE IS BETTER DATA INPUT INTO WEATHER MODELS, HENCE
THE UNCERTAINTY.
THE FIRST SYSTEM WILL BE A POTENT UPPER LOW OVER THE SOUTHWEST
CONUS, WHICH WILL QUICKLY PUSH UP TOWARDS THE GREAT LAKES THROUGH
WEDNESDAY MORNING. THE SECOND SYSTEM, CURRENTLY IN THE GULF OF
ALASKA, WILL DIVE DOWN OUT OF THE NORTHWEST CONUS ON WEDNESDAY INTO
THURSDAY. STARTING TO SEE A FAIR AMOUNT AGREEMENT ON HOW THESE TWO
FEATURES MERGE AND INTERACT ACROSS THE CENTRAL CONUS, BUT STILL
WOULD LIKE TO SEE A FEW MORE CONSISTENT RUNS BEFORE LANDING ON A
PARTICULAR SOLUTION.
AT ANY RATE, AS THESE SYSTEMS INTERACT, A STRONG LOW PRESSURE SYSTEM
WILL LIKELY DEVELOP NEAR THE GREAT LAKES. SOMETIME LATE WEDNESDAY
INTO THURSDAY. THE SYSTEM WILL THEN MAKE ITS WAY ACROSS THE REGION
INTO FRIDAY. AS THIS ALL HAPPENS, WE COULD SEE SEVERAL HAZARDS,
INCLUDING HEAVY RAIN, GUSTY WINDS, COASTAL FLOODING, AND MOUNTAIN
SNOW. AGAIN, STILL LOTS OF UNCERTAINTY, BUT IF THIS PANS OUT AS
MODEL GUIDANCE IS TRENDING TOWARDS, IT COULD BE A VERY IMPACTFUL
EVENT ACROSS THE MID-ATLANTIC.
AVIATION /19Z FRIDAY THROUGH WEDNESDAY/
LOW CEILINGS HAVE PERSISTED ACROSS MUCH OF THE AREA. HOWEVER,
THERE HAVE BEEN IMPROVEMENTS THIS THE MORNING WITH TERMINALS
SITTING BETWEEN VFR AND MVFR. THIS COMES WITH DRY CONDITIONS AND
PERSISTENT NORTHWESTERLY WINDS. EXPECT VFR CONDITIONS THROUGH
THE REMAINDER OF THE WEEKEND UNDERNEATH HIGH PRESSURE. GRADIENTS
REMAIN TIGHT WHICH SUPPORTS NORTHWESTERLY GUSTS UP TO 25 TO
PERHAPS 30 KNOTS ON SATURDAY. LESS WIND IS EXPECTED ON SUNDAY
WITH HIGH PRESSURE NEARBY.
NO SIGNIFICANT WEATHER IS EXPECTED TO IMPACT THE TERMINALS AS HIGH
PRESSURE WILL ONCE AGAIN DOMINATE THE WEATHER PATTERN ON MONDAY AND
TUESDAY.
MARINE
SMALL CRAFT ADVISORIES CURRENTLY ENCOMPASS ALL WATERS OUTSIDE
THE UPPER TIDAL POTOMAC. RECENT OBSERVATIONS HAVE MAINLY FALLEN
SHORT OF THE 18 TO 20 KNOT THRESHOLD. HOWEVER, DO ANTICIPATE AN
UPTICK LATER THIS AFTERNOON INTO THE EVENING. AS SUCH, SMALL
CRAFT ADVISORIES WILL REMAIN IN EFFECT THROUGH TONIGHT AND INTO
SATURDAY. NORTHWESTERLY WINDS PICK UP IN STRENGTH ON SATURDAY
GIVEN A RELATIVELY TIGHT GRADIENT WITH LOW PRESSURE NEAR NOVA
SCOTIA AND HIGH PRESSURE ACROSS THE EASTERN U.S. WILL LIKELY
NEED TO EXTEND THESE ADVISORIES OVER PORTIONS OF THE WATERS INTO
SATURDAY NIGHT. WINDS TURN MORE WEST TO SOUTHWESTERLY THE SECOND
HALF OF SUNDAY WITH GUSTS STAYING BELOW 15 KNOTS.
A WEAK UPPER-LEVEL DISTURBANCE MOVING BY TO OUR NORTH COULD BRIEFLY
PICK WINDS BACK UP OUT OF THE NW ON MONDAY, WHICH COULD NEAR SCA
CRITERIA. WINDS THEN TAPER OFF BELOW SCA CRITERIA ON TUESDAY.
FIRE WEATHER
DRIER AIR RETURNS WITH HIGH PRESSURE AND GUSTY NORTH TO
NORTHWESTERLY FLOW FOR THE START OF THE WEEKEND. WIND GUSTS UP
TO 20 TO 25 KTS ARE POSSIBLE SATURDAY WITH MINIMUM RH VALUES
FALLING BACK INTO THE 40 TO 50 PERCENT RANGE. SIMILAR MINIMUM RH
CONDITIONS (35 TO 45 PERCENT) ARE EXPECTED SUNDAY WITH WIND
GUSTS LESS THAN 15 KTS.
HIGHEST POTENTIAL FOR ELEVATED FIRE WEATHER CONDITIONS THIS WEEKEND
INTO EARLY NEXT WEEK WOULD BE ACROSS NORTHEAST MD AND THE MD/PA LINE
WHERE RAINFALL TOTALS WERE LESS THAN A TENTH OF AN INCH OVER THE
PAST 36 HOURS. THE ADDED DROUGHT IN THESE LOCATIONS WILL FURTHER
THIS CONCERN. WILL CONTINUE TO MONITOR THE NEED FOR ANY FIRE
WEATHER RELATED PRODUCTS. THE EXPECTED GRADIENT IN RH VALUES MAY
BE QUITE TIGHT IN NATURE.
TIDES/COASTAL FLOODING
TIDAL ANOMALIES REMAIN ELEVATED THIS AFTERNOON, GENERALLY
RUNNING BETWEEN 1.25 AND 1.75 FEET. COASTAL FLOOD HEADLINES
CONTINUE WITH MINOR FLOODING AT ANNAPOLIS, SOLOMANS ISLAND,
STRAITS POINT, DAHLGREN, ALEXANDRIA, AND THE WASHINGTON DC SW
WATERFRONT THROUGH HIGH TIDE, WITH ACTION LEVELS POSSIBLE AT A
FEW OTHER SITES UNTIL WATER LEVELS RECEDE. ANOMALIES SLOWLY
BEGIN TO FALL THIS WEEKEND GIVEN NORTHWESTERLY WINDS.
LWX WATCHES/WARNINGS/ADVISORIES
DC...COASTAL FLOOD ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR DCZ001.
MD...SMALL CRAFT ADVISORY UNTIL 6 PM EST SATURDAY FOR MDZ008.
COASTAL FLOOD ADVISORY UNTIL 10 PM EST THIS EVENING FOR MDZ014.
COASTAL FLOOD ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR
MDZ016>018.
VA...COASTAL FLOOD ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR VAZ054.
COASTAL FLOOD ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR
VAZ057.
WV...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 PM EST SATURDAY FOR ANZ530>534-
536>543.
SMALL CRAFT ADVISORY FROM 7 AM TO 6 PM EST SATURDAY FOR ANZ535.
SYNOPSIS...BRO
NEAR TERM...BRO
SHORT TERM...BRO
LONG TERM...CJL
AVIATION...BRO/CJL
MARINE...BRO/CJL
FIRE WEATHER...BRO/EST
TIDES/COASTAL FLOODING...BRO/EST
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