918
FXUS61 KLWX 180859
AFDLWX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
359 AM EST MON NOV 18 2024
SYNOPSIS
A SURFACE TROUGH WILL PASS THROUGH TODAY. A DRY COLD FRONT WILL
DROP INTO THE AREA TONIGHT, THEN RETURN NORTHWARD AS A WARM
FRONT TUESDAY AFTERNOON. AN AREA OF LOW PRESSURE WILL DEVELOP
NEAR THE MID-ATLANTIC WEDNESDAY NIGHT INTO THURSDAY, THEN TRACK
TOWARD NEW ENGLAND THROUGH THE END OF THE WEEK DRAGGING A SERIES
OF COLD FRONTS THROUGH THE REGION.
NEAR TERM /THROUGH TONIGHT/
HIGH CLOUDS THIS MORNING WILL GIVE WAY TO MORE SUNSHINE DURING
THE AFTERNOON. A SURFACE TROUGH WILL PASS THROUGH THE AREA LATER
THIS MORNING WITH NW DOWNSLOPE WINDS WARMING TEMPS TO NEAR 70.
A DRY COLD FRONT WILL PASS THROUGH THE AREA TONIGHT WITH ONLY
MID-HIGH LEVEL CLOUDS EXPECTED.
SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/
FRONT WILL LIFT NORTH AS A WARM FRONT TUE AFTERNOON INTO
WEDNESDAY WITH LIGHT SHOWERS POSSIBLE AS A WEAK WAVE LOW
PRESSURE DEVELOPS ALONG THE FRONT.
TURNING MILDER WEDNESDAY AHEAD OF LOW PRESSURE OVER THE OH RIVER
VALLEY. AMPLIFLYING UPPER TROUGH OVER THE UPPER MIDWEST INTO THE
OH VALLEY WILL INDUCE SFC CYCLOGENESIS OVER THE MID ATLANTIC WED
NIGHT AS TROUGH TAKES ON A NEGATIVE TILT. A LINE OF SHALLOW
CONVECTIVE SHOWERS IS EXPECTED ALONG AND BEHIND THE STRONG
FRONTAL PASSAGE AND LEADING EDGE OF CYCLONIC VORTICITY
ADVECTION. THE FRONT WILL BE ACCOMPANIED BY A SHARP INCREASE IN
WINDS AND A SHARP TEMPERATURE DROP WITH SHOWERS TURNING QUICKLY
INTO SNOW SHOWERS ACROSS THE MOUNTAINS. GUSTS OF 35-40 MPH MAY
ACCOMPANY THE FRONT. SOME GUIDANCE IS INDICATING THE POTENTIAL
FOR 60 MPH GUSTS ACROSS THE MOUNTAINS. SNOW ACCUMULATIONS OVER
THE MOUNTAINS IS EXPECTED TO REMAIN MINIMAL THROUGH 12Z THU.
LONG TERM /THURSDAY THROUGH SUNDAY/
BY THURSDAY MORNING, THE SURFACE FRONT WILL BE OFFSHORE WHILE LOW
PRESSURE STRENGTHENS TOWARD LONG ISLAND. THE UPPER LOW WILL BE
LAGGING SOMEWHERE BETWEEN THE GREAT LAKES AND MID ATLANTIC.
EVENTUALLY THE TWO WILL CONSOLIDATE WHILE SLOWLY PIVOTING TOWARD NEW
ENGLAND THROUGH SATURDAY. FORECAST SPECIFICS (SUCH AS TIMING AND
WHETHER HEADLINE THRESHOLDS WILL BE MET) WILL DEPEND ON THE
EVOLUTION OF THIS SYSTEM, WHICH STILL SHOWS SOME VARIANCE FROM MODEL
RUN TO RUN. THESE GENERAL THEMES STILL PREVAIL HOWEVER:
THE MAIN HAZARD FOCUS WILL BE ON UPSLOPE SNOW, WHICH WILL LIKELY BE
PRETTY PERSISTENT FROM SOME TIME ON THURSDAY THROUGH SATURDAY. BOUTS
OF HEAVIER SNOW AREN'T OUT OF THE QUESTION. MULTI-DAY TOTALS COULD
REACH DOUBLE DIGITS ON HIGHER PEAKS WEST OF THE DIVIDE. GUSTY WINDS
COULD ALSO RESULT IN BLOWING AND DRIFTING SNOW IN ADDITION TO
REDUCING THE VISIBILITY. AT LEAST SOME PERIODS OF DIFFICULT TRAVEL
SHOULD BE PLANNED FOR, ALTHOUGH THERE MAY BE BREAKS AT TIMES AS WELL
AS DAYTIME TEMPERATURES EDGING ABOVE FREEZING. SOME SNOW SHOWERS
(WITH MUCH LESSER ACCUMULATIONS) COULD OCCUR ON THE RIDGES AS FAR
EAST AS THE BLUE RIDGE/CATOCTIN MOUNTAINS. LOWER ELEVATIONS COULD
SEE ISOLATED TO SCATTERED RAIN SHOWERS AT TIMES, MAINLY WEST OF THE
BLUE RIDGE AND NORTH OF I-66/US-50. PARTLY TO MOSTLY CLOUDY SKIES
WILL PREVAIL.
WIND GUSTS WILL GENERALLY RANGE BETWEEN 25-40 MPH DURING THE DAYTIME
PERIODS THURSDAY THROUGH SATURDAY. THE HIGHER ELEVATIONS STAND THE
GREATEST CHANCE OF SEEING SOME GUSTS CLOSER TO WIND ADVISORY
CRITERIA.
DAYTIME TEMPERATURES WILL DROP BELOW NORMAL, WITH HIGHS RANGING FROM
THE MID 40S TO MID 50S. THURSDAY NIGHT MAY HAVE THE BEST CHANCE FOR
LOWER ELEVATIONS TO REACH FREEZING, ALTHOUGH THIS WILL DEPEND ON
CLOUDS AND WIND. OTHERWISE LOWS WILL BE IN THE MID 30S TO LOWER 40S.
THE UPPER LOW IS FORECAST TO MOVE INTO MARITIME CANADA SUNDAY.
SURFACE HIGH PRESSURE WILL NOSE IN FROM THE SOUTH WHILE A SHORTWAVE
RIDGE APPROACHES FROM THE WEST. THIS WILL LEAD TO AN OVERALL
DECREASE IN WINDS AND CLOUD COVER, ALTHOUGH TEMPERATURES WILL REMAIN
ON THE COOL SIDE OF NORMAL.
AVIATION /08Z MONDAY THROUGH FRIDAY/
NW WINDS 10 KT TODAY, BECOMING LIGHT AND VARIABLE TONIGHT AND
TUE. S WINDS WED, BECOMING NW WED NIGHT AND GUSTING TO 35 KT
BEHIND A STRONG FRONTAL PASSAGE.
LOW PRESSURE WILL SPIN NORTHEAST OF THE AREA THURSDAY AND FRIDAY.
THE MAIN IMPACT WILL BE FROM WESTERLY WINDS GUSTING 20-30 KT,
ESPECIALLY DURING THE DAYTIME. THE GREATEST CHANCE OF A RAIN SHOWER
AS WELL AS INTERMITTENT MVFR CEILINGS WILL BE AT MRB.
MARINE
WINDS 10 KT OR LESS THROUGH WED. THEN, RAPID ONSET OF GALE FORCE
WINDS WED NIGHT INTO THU BEHIND A STRONG COLD FRONT.
LOW PRESSURE WILL CONTINUE TO SPIN OFF TO THE NORTHEAST THURSDAY AND
FRIDAY WITH STRONG WESTERLY WINDS IN ITS WAKE. SMALL CRAFT
ADVISORIES ARE LIKELY. A PERIOD OF GALE CONDITIONS IS POSSIBLE,
ALTHOUGH THIS WILL DEPEND ON THE STRENGTH AND LOCATION OF THE
LOW.
TIDES/COASTAL FLOODING
MINOR COASTAL FLOODING IS POSSIBLE AT ANNAPOLIS AND DC WATERFONT
THIS AFTERNOON AND THROUGH THE NEXT SEVERAL DAYS DUE TO SNAP
BACK AND THEN STRENGTHENING SOUTHERLY FLOW.
LWX WATCHES/WARNINGS/ADVISORIES
DC...NONE.
MD...NONE.
VA...NONE.
WV...NONE.
MARINE...NONE.
SYNOPSIS...LFR
NEAR TERM...LFR
SHORT TERM...LFR
LONG TERM...ADS
AVIATION...ADS/LFR
MARINE...ADS/LFR
TIDES/COASTAL FLOODING...LFR
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