804
FXUS61 KLWX 171445
AFDLWX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
1045 AM EDT TUE MAR 17 2026
WHAT HAS CHANGED
EARLIER WIND ADVISORIES IN THE ALLEGHENIES HAVE BEEN CANCELLED.
SMALL CRAFT ADVISORIES HAVE BEEN BEEN EXTENDED BY A FEW HOURS
INTO THE OVERNIGHT HOURS TONIGHT. WINTER WEATHER ADVISORIES WERE
EXPANDED IN AREA IN THE ALLEGHENIES TO INCLUDE EXTREME WESTERN
ALLEGANY AND WESTERN MINERAL COUNTIES, WHERE SNOW SQUALLS ARE
EXPECTED THIS AFTERNOON. CHANCES FOR SNOW SHOWERS WERE
INTRODUCED FOR LATER THIS AFTERNOON INTO EARLY THIS EVENING
ACROSS THE REMAINDER OF THE FORECAST AREA.
KEY MESSAGES
-1) A PERIOD OF UPSLOPE SNOW SHOWERS ARE EXPECTED TODAY ALONG
AND WEST OF THE ALLEGHENY FRONT, WITH SNOW SQUALLS POSSIBLE
THIS AFTERNOON. A FEW SNOW SHOWERS MAY SPILL EAST OF THE
MOUNTAINS THIS AFTERNOON INTO THIS EVENING.
-2) BELOW NORMAL TEMPERATURES ARE EXPECTED THROUGH WEDNESDAY
BEFORE SEASONABLE WEATHER RETURNS FOR THE REMAINDER OF THE
WEEK.
DISCUSSION
KEY MESSAGE 1...A PERIOD OF UPSLOPE SNOW SHOWERS ARE EXPECTED
TODAY ALONG AND WEST OF THE ALLEGHENY FRONT, WITH SNOW SQUALLS
POSSIBLE THIS AFTERNOON. A FEW SNOW SHOWERS MAY SPILL EAST OF
THE MOUNTAINS THIS AFTERNOON INTO THIS EVENING.
ON AND OFF SNOW SHOWERS CONTINUE IN THE ALLEGHENIES THIS MORNING
AS AN UPPER TROUGH OVER THE OHIO VALLEY MAKES SLOW EASTWARD
PROGRESS TOWARD THE AREA. THIS TROUGH AXIS WILL SHARPEN AS IT
SWINGS OVERHEAD LATER THIS EVENING. DURING THE LATE MORNING TO
AFTERNOON PERIOD, THE 00Z NAM SNOW SQUALL PARAMETER LIGHTS UP
ACROSS THE OHIO VALLEY TOWARD THE ALLEGHENY FRONT. WITH FROUDE
NUMBERS BECOMING QUITE LARGE TODAY (5 TO 7), A SIGNIFICANT
AMOUNT OF SPILLOVER IS POSSIBLE. MODEL SOUNDINGS SHOW
INSTABILITY UP THROUGH THE DGZ IN THE MOUNTAINS, AND TO A LESSER
EXTENT FURTHER EAST. SNOW SQUALLS WILL BE POSSIBLE IN THE
ALLEGHENIES THIS AFTERNOON, WITH INSTANTANEOUS SNOWFALL RATES OF
1 TO 2 INCHES PER HOUR POSSIBLE AT TIMES. THIS COULD CREATE
HAZARDOUS TRAVEL CONDITIONS IN THE ALLEGHENIES THIS AFTERNOON.
IN TOTAL, AN ADDITIONAL 2 TO 4 INCHES OF SNOW ARE EXPECTED IN
THE ALLEGHENIES, WHERE WINTER WEATHER ADVISORIES ARE IN EFFECT.
SNOW SHOWERS MAY ALSO BE POSSIBLE TO THE EAST OF THE MOUNTAINS
THIS AFTERNOON INTO EARLY THIS EVENING. EARLIER FORECASTS WERE
UPDATED TO INTRODUCE CHANCES FOR SNOW SHOWERS ACROSS ALL OF THE
FORECAST AREA. WITH HIGH TEMPERATURES IN THE MID 30S TO MID 40S
TO THE EAST OF THE MOUNTAINS, MOST OF THIS SNOW WILL BE NON-
IMPACTFUL. WHILE A LIGHT FLURRY OR SNOW SHOWER COULD BE POSSIBLE
ANYWHERE, HI-RES GUIDANCE IS HIGHLIGHTING TWO MAIN CORRIDORS
WHERE SNOW SHOWERS COULD HAVE A BIT HIGHER COVERAGE. THE FIRST
WILL BE ALONG THE MD/PA BORDER, WHILE THE SECOND WILL BE FROM
THE CENTRAL SHENANDOAH VALLEY EASTWARD ACROSS CENTRAL VIRGINIA
TOWARD SOUTHERN MARYLAND. IF THE SNOW SHOWERS LINGER IN THESE
AREAS UNTIL AFTER DARK, LIGHT ACCUMULATIONS OF LESS THAN AN INCH
COULD BE POSSIBLE.
KEY MESSAGE 2...BELOW NORMAL TEMPERATURES ARE EXPECTED THROUGH
WEDNESDAY BEFORE SEASONABLE WEATHER RETURNS FOR THE REMAINDER OF
THE WEEK.
THE INFLUENCE OF THE EARLIER FRONTAL PASSAGE HAS YIELDED A
DRAMATIC FALL IN TEMPERATURES. AFTER SEEING ABOVE AVERAGE
TEMPERATURES YESTERDAY/MONDAY, TODAY'S FORECAST HIGHS WILL DROP
BY AROUND 20 TO 35 DEGREES. MORE SPECIFICALLY, MANY ARE FORECAST
TO SEE HIGHS IN THE MID 30S TO LOW 40S, WITH UPPER TEENS TO 20S
IN THE MOUNTAINS. BLUSTERY WESTERLY WINDS ON THE ORDER OF 25 TO
35 MPH WILL LOWER WIND CHILLS ACROSS THE METROS TO AROUND
FREEZING. THIS IS ACCOMPANIED BY PASSING CLOUDS AND A FEW SNOW
SHOWERS THAT STREAM OFF THE HIGHER TERRAIN. WINDS GRADUALLY
DECREASE INTO TONIGHT AS AN ANTICYCLONE OVER THE OHIO VALLEY
TREKS TOWARD THE EASTERN SEABOARD. DESPITE SOME RESIDUAL WINDS
AND CLOUD COVER, LOWS TONIGHT PLUNGE INTO THE UPPER TEENS TO 20S
(TEENS FOR THE MOUNTAINS).
THE CONTINENTAL-SCALE PATTERN CONTINUES TO SUPPORT DEEP
TROUGHING ACROSS THE EASTERN U.S. AS AN ANOMALOUS RIDGE SITS
OVER THE SOUTHWESTERN STATES. WHILE THE INITIAL STRONGER
SHORTWAVE PULLS OUT INTO THE ATLANTIC, A WEAKER TROUGH BEGINS TO
DIG ACROSS THE GREAT LAKES AND NORTHEASTERN U.S. THIS WILL
MAINTAIN A CYCLONIC FLOW REGIME INTO WEDNESDAY WHICH SUPPORTS
CONTINUED BELOW AVERAGE TEMPERATURES. WHILE MOST AGAIN STAY IN
THE UPPER 30S TO LOW 40S, EXPECT A WARMING TREND ALONG THE
ALLEGHENIES AS SNOW COMES TO AN END. OVERNIGHT CONDITIONS WILL
ALSO NOT BE QUITE AS COLD OWING TO A SHIFT TO SOUTHERLY FLOW.
OVER THE NEXT SEVERAL DAYS, THE SYNOPTIC FEATURES WILL SLOWLY
MOVE EASTWARD IN TIME. THIS MOVES TROUGHING OFF THE ATLANTIC
COAST WHILE RIDGING TRACKS INTO THE ROCKIES. IN THE NET, HEIGHTS
GRADUALLY RISE THROUGH THE LATE WEEK PERIOD WHICH FOSTERS A
WARMING TREND. SURFACE HIGH PRESSURE LARGELY DOMINATES THE
MID/LATE WEEK PATTERN WHICH WILL SUPPORT A DRY FORECAST. OVER
THE WEEKEND, MULTI-ENSEMBLE TEMPERATURE SPREAD INCREASES AS A
MORE PRONOUNCED SYSTEM MAY IMPACT THE REGION. PRECIPITATION
CHANCES ARE LOW AT THIS TIME, BUT TEMPERATURES LIKELY PEAK OVER
THE WEEKEND WITH HIGHS WELL INTO THE 60S. HOWEVER, SUNDAY HAS
THE MOST VOLATILITY AS THE 75TH PERCENTILE FORECAST HIGH IN D.C.
IS 74 DEGREES AND THE 25TH PERCENTILE IS 52 DEGREES. THUS, THE
SHIFT TO COOLER WEATHER COULD START AS EARLY AS SUNDAY.
AVIATION /14Z TUESDAY THROUGH SATURDAY/
WITH A POST-FRONTAL AIR MASS NOW IN PLACE, A RETURN TO VFR
CONDITIONS HAS OCCURRED. EXPECT IT TO STAY THAT WAY THROUGH MUCH
OF THE WEEK. OVERALL, THE MAIN ISSUE TODAY IS THE BLUSTERY
WESTERLY WINDS WHICH MAY GUST UP TO 30 KNOTS AT TIMES THIS
AFTERNOON. SUCH WINDS SHOULD DIMINISH BEYOND SUNSET AS HIGH
PRESSURE MOVES IN FROM THE OHIO VALLEY.
THIS AREA OF HIGH PRESSURE TAKES OVER DURING THE MID TO LATE
WEEK PERIOD WHICH ALLOWS FOR CONTINUED VFR CONDITIONS. WINDS
SHIFT TO SOUTHERLY BY WEDNESDAY AND THURSDAY, BUT WITH LESS WIND
THAN RECENT DAYS OWING TO WEAKER GRADIENTS. WINDS TURN MORE
SOUTHWESTERLY BY FRIDAY WHILE INCREASING IN STRENGTH BY
SATURDAY. SOME LIGHT SHOWER CHANCES COME IN BY LATE FRIDAY, BUT
RESTRICTIONS LOOK UNLIKELY AT THIS TIME.
MARINE
WESTERLY WINDS SHOULD REMAIN BLUSTERY IN NATURE THROUGH THIS
EVENING. SMALL CRAFT ADVISORIES HAVE BEEN ISSUED ACROSS ALL
WATERS THROUGH THIS EVENING FOR WEST-NORTHWESTERLY GUSTS OF 25
TO 30 KNOTS, ACCOMPANIED BY WAVES OF 2 TO 4 FEET. THE ADVISORIES
LINGER A FEW HOURS LONGER INTO THE OVERNIGHT ACROSS THE WIDER
WATERS OF THE BAY AND LOWER TIDAL POTOMAC.
HIGH PRESSURE BUILDS OVER THE AREA DURING THE MID TO LATE WEEK
PERIOD. THIS FAVORS SUB-ADVISORY WINDS AS GRADIENTS WILL BE
WEAK. PREVAILING SOUTHERLIES ARE LIKELY IN THIS REGIME BEFORE
SHIFTING TO SOUTHWESTERLY BY FRIDAY. SOME INCREASE IN WINDS ARE
POSSIBLE BY SATURDAY WHICH MAY APPROACH ADVISORY LEVELS, BUT
CONFIDENCE IS LOW.
LWX WATCHES/WARNINGS/ADVISORIES
DC...NONE.
MD...SMALL CRAFT ADVISORY UNTIL 1 AM EDT WEDNESDAY FOR MDZ008.
WINTER WEATHER ADVISORY UNTIL 5 PM EDT THIS AFTERNOON FOR
MDZ501.
WINTER WEATHER ADVISORY UNTIL 5 PM EDT THIS AFTERNOON FOR
MDZ509-510.
VA...WINTER WEATHER ADVISORY UNTIL 5 PM EDT THIS AFTERNOON FOR
VAZ503.
WV...WINTER WEATHER ADVISORY UNTIL 5 PM EDT THIS AFTERNOON FOR
WVZ503.
WINTER WEATHER ADVISORY UNTIL 5 PM EDT THIS AFTERNOON FOR
WVZ501-505.
MARINE...SMALL CRAFT ADVISORY UNTIL 1 AM EDT WEDNESDAY FOR ANZ530>534-
537-539>543.
SMALL CRAFT ADVISORY UNTIL 10 PM EDT THIS EVENING FOR ANZ535-
536-538.
DISCUSSION...BRO/KJP
AVIATION...BRO
MARINE...BRO/KJP
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