170
FXUS61 KLWX 020903
AFDLWX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
403 AM EST MON MAR 2 2026
WHAT HAS CHANGED
CONFIDENCE IS INCREASING IN A NARROW, SOMEWHAT BRIEF BAND OF
SNOW THAT WILL AFFECT THE AREA TODAY. MAINLY SUBTLE CHANGES HAVE
OCCURRED TO THE WINTRY MIX FORECAST TONIGHT INTO TUESDAY
MORNING, WITH THE HIGHEST CONFIDENCE OF ACCUMULATIONS CONTINUING
TO BE IN THE HIGHER ELEVATIONS. SOME VARIATIONS TO THE FRONTAL
POSITION AND RAIN CHANCES WILL CONTINUE TO OCCUR DURING THE
SECOND HALF OF THE WEEK.
KEY MESSAGES
- 1) MULTIPLE OF WAVES OF WINTRY PRECIPITATION MAY CAUSE IMPACTS
TO TRAVEL TODAY THROUGH TUESDAY MORNING.
- 2) A WARMING TREND WILL EVOLVE WEDNESDAY THROUGH SUNDAY. RAIN
SHOWERS COULD OCCUR PERIODICALLY. CONFIDENCE IS LOW THAT THEY
WILL BE VERY IMPACTFUL AT THIS TIME.
DISCUSSION
KEY MESSAGE 1...MULTIPLE OF WAVES OF WINTRY PRECIPITATION MAY
CAUSE IMPACTS TO TRAVEL TODAY THROUGH TUESDAY MORNING.
KEY MESSAGE 1 DESCRIPTION...
STRONG HIGH PRESSURE CENTERED NEAR OTTAWA THIS MORNING IS
BEGINNING TO WEDGE DOWN THE EASTERN SIDE OF THE APPALACHIANS.
COLD, DRY AIR CONTINUES TO ADVECT INTO THE AREA ON NORTHEASTERLY
WINDS. MEANWHILE, A SHORTWAVE TROUGH IS MOVING INTO THE OHIO
VALLEY WITH BANDING STRUCTURES ALREADY EVIDENT IN SATELLITE
IMAGERY. MODELS INDICATE THAT A MID LEVEL FRONTOGENESIS AXIS
WILL MOVE INTO THE AREA LATER THIS MORNING. WHILE THE AREA OF
SNOW MAY BE SOMEWHAT BROAD, A MUCH NARROWER BAND OF HIGHER SNOW
RATES LOOKS TO EVOLVE. 00Z MODELS SHOW SPREAD ON WHERE THIS AXIS
WILL SET UP, BUT IT WILL LIKELY BE SOMEWHERE ON EITHER SIDE OF
THE I-66 CORRIDOR. THIS BAND WILL BE FIGHTING BOTH LOW LEVEL DRY
AIR AND EARLY MARCH INSOLATION TO PRODUCE ACCUMULATIONS.
HOWEVER, SOUNDINGS SHOW THE STRONGEST LIFT IN THE DENDRITIC
GROWTH ZONE, SUGGESTING EFFICIENT SNOW PRODUCTION. SOME GUIDANCE
PRODUCES UP TO A QUARTER INCH OF LIQUID EQUIVALENT IN THIS
BAND, POTENTIALLY HIGHER IN THE ALLEGHENIES. WITH THE POTENTIAL
FOR 1-3 INCHES OF SNOW OCCURRING QUICKLY IN THE HIGHER TERRAIN,
STARTED A WINTER WEATHER ADVISORY LATE THIS MORNING ALONG AND
WEST OF THE BLUE RIDGE. WHILE SNOW REMAINS LIKELY TO THE EAST IN
THE WASHINGTON AND PERHAPS BALTIMORE METRO AREAS, MARGINAL LOW
LEVEL TEMPERATURES (MID 30S), DRIER AIR, AND A DECREASING QPF
SIGNAL MAKES IT SEEM LIKE MOST ACCUMULATIONS WILL BE ON GRASSY
AND ELEVATED SURFACES AND HAVE LITTLE TRAVEL IMPACT. WE WILL
CONTINUE TO MONITOR THIS SITUATION AND MAY NEED TO CHANGE THE
EXISTING ADVISORY OR ISSUE A SPECIAL WEATHER STATEMENT SHOULD
CONFIDENCE IN IMPACTS INCREASE.
THERE WILL BE A BREAK IN PRECIPITATION DURING THE LATE AFTERNOON
TO EARLY EVENING AS THE SHORTWAVE EXITS, EXCEPT PERHAPS ACROSS
SOUTHWESTERN PORTIONS OF THE FORECAST AREA, WHERE A WINTRY MIX
WILL LIKELY CONTINUE IN DEEPER MOIST ISENTROPIC ASCENT. DURING
THE DAYLIGHT HOURS, MOST OF THE ACCUMULATIONS WILL BE IN THE
HIGHER ELEVATIONS. THE SECOND WAVE OF ASCENT SPREADS
NORTHEASTWARD TONIGHT. THE LEADING EDGE MAY STILL BE SNOW, BUT
PRECIPITATION TYPE WILL CHANGE OVER TO SLEET AND PRIMARILY
FREEZING RAIN AS TIME GOES ON DUE TO WARM ADVECTION ALOFT. WHILE
A FEW TENTHS OF AN INCH OF SNOW/SLEET ACCUMULATION ARE ADDED TO
THE STORM TOTAL HERE, THE PRIMARY IMPACT WILL BE FROM FREEZING
RAIN. SURFACE TEMPERATURES WILL BE INCREASINGLY MARGINAL (AND
PERHAPS MOSTLY ABOVE FREEZING) WITH LOWER ELEVATIONS AND
SOUTH/EASTWARD EXTENT. HAVE ISSUED A WINTER WEATHER ADVISORY
WHERE CONFIDENCE IS HIGHEST IN IMPACTFUL ACCUMULATIONS. LATER
EXPANSIONS COULD BE REQUIRED. LOWER ELEVATIONS WILL ONLY SEE A
LIGHT GLAZE OF ICE, PERHAPS MOSTLY ON ELEVATED SURFACES.
HOWEVER, THE RIDGES COULD SEE ONE TENTH TO ONE QUARTER INCH OF
ICE. LIKELY NOT ENOUGH TO CAUSE MANY TREE/POWER IMPACTS, BUT
TRAVEL COULD BE DIFFICULT. THE HIGH IS FAIRLY TRANSIENT, SO
WARMER AIR SHOULD SLOWLY START WORKING NORTHWARD LATE TONIGHT
THROUGH TUESDAY MORNING, AT LEAST ENOUGH TO CHANGE PRECIPITATION
TO PLAIN RAIN. THE RAIN WILL ALSO START TAPERING OFF AROUND THE
SAME TIME, AS MOST OF THE FORCING LIFTS NORTH OF THE AREA
TUESDAY AFTERNOON. HAVE THE END TIMES FOR THE ADVISORY GENERALLY
ON THE SLOWER END OF GUIDANCE DUE TO COLD AIR DAMMING EROSION
BIAS.
ANOTHER WAVE OF RAIN MAY MOVE ACROSS THE AREA TUESDAY NIGHT, BUT
TEMPERATURES MAY LARGELY HOLD STEADY IN THE 40S FOR MOST AREAS.
KEY MESSAGE 2...A WARMING TREND WILL EVOLVE WEDNESDAY THROUGH
SUNDAY. RAIN SHOWERS COULD OCCUR PERIODICALLY. CONFIDENCE IS
LOW THAT THEY WILL BE VERY IMPACTFUL AT THIS TIME.
KEY MESSAGE 2 DESCRIPTION...
AN UPPER LEVEL RIDGE WILL BECOME THE DOMINANT FEATURE OVER THE
SOUTHEASTERN US DURING THE SECOND HALF OF THE WEEK. A TRAIN OF
LOW PRESSURE SYSTEMS AND THEIR ASSOCIATED FRONTS WILL BE MAINLY
TO OUR NORTH THROUGHOUT THE PERIOD. WE COULD ENCOUNTER A COLD
FRONTAL PASSAGE AT ONE POINT OR ANOTHER DURING THIS PERIOD, BUT
TEMPERATURES WILL BE WELL ABOVE AVERAGE EACH DAY. THE CHANCE OF
RAIN SHOWERS WILL BE NEAR OR AT TIMES OVER US DEPENDING ON THE
TRACK OF INDIVIDUAL LOW PRESSURES AND HOW MUCH THE FRONT BUCKLES.
TEMPERATURES WILL BE 15 TO 20 DEGREES ABOVE AVERAGE DURING THE
DAYS THAT HAVE MORE SUN THAN CLOUDS AND A SOUTHERLY RETURN FLOW.
THE PERIOD OF FRIDAY INTO FRIDAY NIGHT SEEMS TO HINT OF A
POSSIBLE BACKDOOR COLD FRONT. THIS FRONT COULD BRING MORE IN THE
WAY OF CLOUDS AND RAIN CHANCES. TEMPERATURES ON THE NORTH AND
NORTHEAST SIDE OF THE FRONT COULD END UP BEING 20 DEGREES COOLER
THAN TEMPERATURES ON THE SOUTH AND SOUTHWEST SIDE OF THE FRONT
IN OUR CENTRAL AND WESTERN ZONES.
AVIATION /08Z MONDAY THROUGH FRIDAY/
DESPITE HIGH PRESSURE AND BENIGN CONDITIONS TO START THE DAY, A
BAND OF SNOW WILL SPREAD INTO THE AREA DURING THE LATE MORNING
TO EARLY AFTERNOON. THERE IS UNCERTAINTY WHETHER THE MOST
INTENSE PART OF THIS BAND WILL LINE UP WITH IAD/DCA OR
MRB/BWI/MTN. THE SNOW COULD BE MODERATE FOR A TIME. A LULL IN
PRECIPITATION IS LIKELY LATE IN THE AFTERNOON INTO THIS EVENING,
BUT CEILINGS WILL QUICKLY CRASH TO MVFR AND IFR. HOWEVER, CHO
MAY HAVE PRECIPITATION CONTINUE DURING THIS TIME. A WINTRY MIX
WILL SPREAD NORTHWARD TONIGHT, REACHING BWI/MTN LAST. THERE'S
SOME UNCERTAINTY IN PRECIPITATION TYPE WITH MARGINAL
TEMPERATURES. SNOW AND SLEET ARE POSSIBLE AT THE START,
EVENTUALLY BECOMING FREEZING RAIN OR RAIN. PRECIPITATION SHOULD
CHANGE TO RAIN BY MID MORNING TUESDAY BEFORE TAPERING OFF
SOMEWHAT IN THE AFTERNOON. IFR TO MVFR CEILINGS LIKELY CONTINUE
HOWEVER THROUGH TUESDAY NIGHT.
SOME IMPROVEMENT IN CONDITIONS IS EXPECTED WEDNESDAY, ALTHOUGH
ADDITIONAL RAIN AND PERSISTENT LOW CEILINGS ARE POSSIBLE ACROSS
THE NORTHERN TERMINALS.
VFR CONDITIONS EXPECTED FOR THE MOST PART THURSDAY THROUGH FRIDAY
NIGHT. WINDS SOUTH TO SOUTHWEST 5 TO 10 KNOTS THROUGH THE PERIOD.
SHOULD A BACKDOOR FRONT EVOLVE, THEN WINDS WOULD BE NORTHEAST 10 TO
15 KNOTS AND OCCUR ON FRIDAY INTO FRIDAY NIGHT. ANY SHOWERS OR AREAS
OF DRIZZLE AND FOG COULD RESULT IN MVFR OR IFR CONDITIONS.
MARINE
MARGINAL ADVISORY CONDITIONS IN NORTHEAST WINDS CONTINUE ALONG
THE BAY THROUGH EARLY MORNING BEFORE WINDS TAPER OFF. WINDS WILL
EVENTUALLY BECOME SOUTHERLY TUESDAY AS A WARM FRONT PASSES,
ALTHOUGH ADVISORY CONDITIONS ARE LOOKING LESS LIKELY TUESDAY
NIGHT. DEPENDING ON HOW THE FRONT WAVERS, LIGHT SOUTH TO EAST
WINDS ARE FORECAST WEDNESDAY AND WEDNESDAY NIGHT.
NO MARINE HAZARDS THURSDAY THROUGH FRIDAY NIGHT. HOWEVER, THERE
COULD OCCASIONALLY BE VISIBILITY IMPACTS IN THE NORTHERN AND
CENTRAL CHESAPEAKE BAY DUE TO BACKDOOR COLD FRONTS POSING
DRIZZLE, RAIN OR FOG. THAT SEEMS TO BE MAINLY FRIDAY INTO
FRIDAY NIGHT. WINDS GENERALLY SOUTH TO SOUTHWEST 5 TO 10 KNOTS
EACH PERIOD. A BACKDOOR FRONT COULD BRING NORTHEAST WINDS 10
KNOTS ANY PERIOD.
LWX WATCHES/WARNINGS/ADVISORIES
DC...NONE.
MD...WINTER WEATHER ADVISORY FROM 10 PM THIS EVENING TO 1 PM EST
TUESDAY FOR MDZ003-004-501-502-510.
WINTER WEATHER ADVISORY FROM 1 AM TO 1 PM EST TUESDAY FOR
MDZ005-006-507.
WINTER WEATHER ADVISORY FROM 10 PM THIS EVENING TO 10 AM EST
TUESDAY FOR MDZ503>506-509.
VA...WINTER WEATHER ADVISORY FROM 10 PM THIS EVENING TO 10 AM EST
TUESDAY FOR VAZ040-051-053-501-502-505-506-526-527.
WINTER WEATHER ADVISORY FROM 1 PM THIS AFTERNOON TO 7 AM EST
TUESDAY FOR VAZ025-026-508.
WINTER WEATHER ADVISORY FROM 10 AM THIS MORNING TO 10 AM EST
TUESDAY FOR VAZ027>031-507.
WINTER WEATHER ADVISORY FROM 4 PM THIS AFTERNOON TO 7 AM EST
TUESDAY FOR VAZ037>039-050.
WINTER WEATHER ADVISORY FROM 10 AM THIS MORNING TO 7 AM EST
TUESDAY FOR VAZ503-504.
WV...WINTER WEATHER ADVISORY FROM 10 PM THIS EVENING TO 1 PM EST
TUESDAY FOR WVZ051>053-503-504.
WINTER WEATHER ADVISORY FROM 10 AM THIS MORNING TO 10 AM EST
TUESDAY FOR WVZ050-055.
WINTER WEATHER ADVISORY FROM 10 AM THIS MORNING TO 7 AM EST
TUESDAY FOR WVZ501-502-505-506.
MARINE...SMALL CRAFT ADVISORY UNTIL 9 AM EST THIS MORNING FOR
ANZ532>534-537-540-541-543.
DISCUSSION...ADS/KLW
AVIATION...ADS/KLW
MARINE...ADS/LFR/KLW
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