952
FXUS61 KLWX 161913
AFDLWX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
213 PM EST SAT NOV 16 2024
SYNOPSIS
HIGH PRESSURE WILL BUILD OVER THE MID-ATLANTIC THROUGH SUNDAY.
A WEAK, DRY COLD FRONT WILL CROSS THE AREA MONDAY MORNING.
ANOTHER DRY COLD FRONT LOOKS TO DROP IN FROM THE NORTH MONDAY
NIGHT, THEN RETURN NORTH AS WARM FRONT TUESDAY INTO WEDNESDAY AS
STRONG LOW PRESSURE MOVES FROM THE PLAINS TO THE GREAT LAKES.
UNCERTAINTY INCREASES AFTER THAT, BUT THE GENERAL IDEA IS FOR A
SECONDARY AREA OF LOW PRESSURE TO DEVELOP AND DEEPEN RATHER
SIGNIFICANTLY SOMEWHERE IN THE VICINITY OF THE MID-ATLANTIC OR
NORTHEAST THURSDAY INTO FRIDAY BEFORE DRIFTING EAST.
NEAR TERM /THROUGH TONIGHT/
RIDGING WILL SLOWLY BUILD IN ALOFT WHILE HIGH PRESSURE BUILDS IN
AT THE SURFACE THROUGH TONIGHT. GUSTY NORTHWEST WINDS WILL
PERSIST BETWEEN LOW PRESSURE NEAR THE CANADIAN MARITIMES AND THE
BUILDING AREA OF HIGH PRESSURE. GUSTS OF 20 TO 30 MPH ARE LIKELY
INTO THE EARLY EVENING HOURS BEFORE SUBSIDING. LOW TEMPERATURES
WILL FALL INTO THE 30S (UPPER 20S SHELTERED VALLEYS) AS WINDS
SLACKEN AND A FEW HIGH CLOUDS DRIFT OVERHEAD.
SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/
HIGH PRESSURE WILL MOVE OVERHEAD SUNDAY, THEN MOVE OFFSHORE
SUNDAY NIGHT. THIS WILL TURN WINDS TO LIGHT OUT OF THE
SOUTHWEST. DESPITE THE CHANGE IN DIRECTION, THE LIGHTER SPEEDS
AND LACK OF DOWNSLOPING MAY ACTUALLY RESULT IN HIGH TEMPERATURES
JUST A BIT COOLER THAN SATURDAY.
HIGH CLOUDS WILL CONTINUE TO INCREASE AHEAD OF A COLD FRONT
APPROACHING FROM THE GREAT LAKES. THIS FRONT WILL CROSS THE
MID-ATLANTIC EARLY MONDAY, BUT MOISTURE LOOKS SCANT. ASIDE FROM
A FEW ISOLATED SHOWERS ALONG AND WEST OF THE ALLEGHENY FRONT IN
WESTERN MARYLAND, IT SHOULD BE A DRY FRONTAL PASSAGE. WINDS
WILL TURN TO THE NORTHWEST AND GUST 15 TO 25 MPH MONDAY, WITH
THE DOWNSLOPE COMPONENT AND LACK OF STRONGER COLD ADVECTION
RESULTING IN HIGH TEMPERATURES WELL INTO THE 60S TO PERHAPS NEAR
70 (50S IN THE MOUNTAINS).
WINDS BECOME LIGHT AS ANOTHER DRY COLD FRONT DROPS INTO THE
AREA FROM THE NORTH MONDAY NIGHT, BUT INCREASING HIGH CLOUDS
SHOULD KEEP TEMPERATURES FROM DROPPING TOO DRASTICALLY.
LONG TERM /TUESDAY THROUGH SATURDAY/
A HIGHLY AMPLIFIED SYNOPTIC PATTERN WILL BE FEATURED DURING THE
PERIOD WHICH INCLUDES A FAIRLY POTENT UPPER LOW SET TO IMPACT THE
AREA LATE WEDNESDAY THROUGH AT LEAST FRIDAY. INITIAL RIDGING OVER
THE EASTERN SEABOARD GRADUALLY SLIDES OFFSHORE AHEAD OF THE
MENTIONED SYSTEM. THE LATEST ENSEMBLE SYSTEMS SHOW 500-MB HEIGHTS
AROUND 2 STANDARD DEVIATIONS BELOW CLIMATOLOGY FOR MID-NOVEMBER. AS
HEIGHT FALLS PUSH ACROSS THE OHIO VALLEY, A FORMIDABLE SURFACE
CYCLONE UNFOLDS WITH RAPID DEEPENING EXPECTED BETWEEN WEDNESDAY
EVENING AND THURSDAY MORNING. SOME SOLUTIONS DROP PRESSURES INTO THE
970 TO 980 MB RANGE, ALTHOUGH TRACKS ARE QUITE VARIABLE. A
SECONDARY/TRIPLE POINT LOW FORMS OVER THE NORTHERN MID-ATLANTIC
THURSDAY MORNING. SPATIAL SPREAD DOES EXIST AS SHOWN ACROSS THE
ARRAY OF GLOBAL ENSEMBLE SYSTEMS. EVENTUALLY THE FRONTAL SYSTEM
CONSOLIDATES WHILE TREKKING TOWARD SOUTHERN NEW ENGLAND LATE THURSDAY
INTO FRIDAY. HEADING INTO THE FIRST HALF OF THE WEEKEND, THE
EXPANSIVE UPPER CIRCULATION SETTLES OVER NEW ENGLAND BEFORE REACHING
FAR SOUTHEASTERN CANADA BY SUNDAY.
LOOKING MORE SPECIFICALLY AT THE SENSIBLE WEATHER AHEAD, SOME SHOWER
ACTIVITY MAY PUSH INTO THE AREA ON TUESDAY AS A WARM FRONT
APPROACHES FROM THE SOUTHWEST. IN PARTICULAR, THE BEST SHOT OF ANY
SUCH SHOWERS WOULD BE FROM THE CENTRAL VIRGINIA PIEDMONT WESTWARD.
OTHERWISE, TUESDAY IS FORECAST TO YIELD A MIX OF CLOUDS AND SUN WITH
HIGHS IN THE LOW TO MID 60S (50S ACROSS THE MOUNTAINS). WEDNESDAY
WILL ACT AS A DAY OF TRANSITION AS CLOUDS FURTHER INCREASE AHEAD OF
THE POTENT TROUGH/FRONTAL SYSTEM. STEADY WARM ADVECTION DOES HELP
CARRY TEMPERATURES INTO THE MID 60S TO LOW 70S. HOWEVER, ANTICIPATE
INCREASING SHOWER CHANCES WEDNESDAY EVENING INTO THE NIGHT. FORECAST
SOUNDINGS SHOW SATURATION UP TO AROUND 10,000-12,000 FEET WITH DRY
PROFILES ABOVE. WITHIN THIS CLOUD LAYER, WIND SHEAR IS RATHER HIGH,
BUT WITH VERY LOW CAPE/INSTABILITY VALUES. THIS HIGH SHEAR-LOW CAPE
SETUP COULD LEAD TO SOME VERY GUSTY SHOWERS LATE WEDNESDAY. IT
APPEARS THIS ACTION IS EITHER TIED TO THE STRONG COLD FRONT OR SOME
PRE-CONVECTIVE LINE. THIS BOUNDARY CLEARS THE I-95 CORRIDOR BY
THURSDAY MORNING WITH ADDITIONAL SHOWERS POSSIBLE THROUGH FRIDAY
WITH THE UPPER LOW ITSELF. PERIODS OF BRISK WINDS ARE LIKELY
THURSDAY THROUGH SATURDAY WITH DAILY HIGHS IN THE UPPER 40S TO MID
50S.
HEADING UP INTO THE MOUNTAINS, GUIDANCE CONTINUES TO FAVOR A MULTI-
DAY PERIOD OF SNOW SHOWERS ALONG THE ALLEGHENY FRONT. THE INITIAL
ACTIVITY THROUGH WEDNESDAY NIGHT WILL BE COMPRISED OF RAIN SHOWERS.
HOWEVER, RAPID COOLING OF THE COLUMN ENSUES AS THE COLD UPPER LOW
TRACKS OVERHEAD. STRONG ASCENT COMBINED WITH FAVORABLE OROGRAPHIC
EFFECTS SHOULD YIELD AMPLE OPPORTUNITY FOR MODERATE TO HEAVY
SNOW SHOWERS, PARTICULARLY ON THURSDAY INTO FRIDAY. THE SNOW
COMBINED WITH THE BLUSTERY WINDS MAY LEAD TO SIGNIFICANT
REDUCTIONS IN VISIBILITY AND HAZARDOUS TRAVEL CONDITIONS.
CONTINUE TO MONITOR THE LATEST FORECAST AT WEATHER.GOV/LWX.
HEADING INTO THE WEEKEND, UPSLOPE SNOW SHOWERS LIKELY PERSIST
GIVEN CYCLONIC FLOW ALOFT PERSISTS. THIS WOULD ADD TO ANY
SNOWPACK ALREADY ON THE GROUND. FROM THURSDAY ONWARD, DAILY
HIGHS LARGELY STAY IN THE LOW TO MID 30S, ACCOMPANIED BY LOW
TEMPERATURES IN THE MID 20S TO LOW 30S.
AVIATION /18Z SATURDAY THROUGH THURSDAY/
GUSTY NW WINDS WILL SLACKEN AROUND SUNSET. VFR IS EXPECTED
THROUGH THE TAF PERIOD. LIGHT NW WINDS TONIGHT WILL BECOME SW
SUNDAY, THEN SHIFT BACK TO THE NW MONDAY WITH GUSTS OF 15 TO 20
KTS AS A DRY COLD FRONT CROSSES. VFR CONDITIONS WILL PREVAIL
DURING THIS TIME.
VFR CONDITIONS ARE EXPECTED ON TUESDAY, ACCOMPANIED BY A MIX OF
CLOUDS AND SUN. ANY SHOWERS THAT DO REACH THE WESTERN TERMINALS
SHOULD NOT CAUSE ANY RESTRICTIONS. A STRONG FRONTAL SYSTEM BRINGS
DETERIORATING CONDITIONS TO THE ENTIRE REGION WEDNESDAY EVENING INTO
THURSDAY. IN PARTICULAR, A GUSTY LINE OF SHOWERS MAY PUSH THROUGH
LATE WEDNESDAY AS A COLD FRONT APPROACHES FROM THE WEST.
RESTRICTIONS ARE CERTAINLY LIKELY DURING PERIODS OF THIS TIME.
SHOWERS CONTINUE INTO THURSDAY WITH SOUTHWESTERLY GUSTS UP TO 25 TO
30 KNOTS.
MARINE
WINDS WILL GRADUALLY SUBSIDE TONIGHT INTO SUNDAY MORNING, THEN
BECOME SOUTHWEST SUNDAY AFTERNOON. A DRY COLD FRONT WILL CROSS
MONDAY TURNING WINDS BACK TO THE NORTHWEST WIND GUSTS OF 15 TO
20 KNOTS POSSIBLE MONDAY.
GUSTS STAY BELOW SMALL CRAFT ADVISORY LEVELS THROUGH WEDNESDAY
AFTERNOON AMIDST A FAIRLY PERSISTENT SOUTH TO SOUTHWESTERLY WIND.
SOME CHANNELING EFFECTS ARE POSSIBLE BY WEDNESDAY EVENING WHICH MAY
BRING ADVISORY-CALIBER WINDS TO SOME OF THE WATERS. WINDS CONTINUE
TO INTENSIFY INTO WEDNESDAY NIGHT AND THURSDAY AS A POTENT FRONTAL
SYSTEM PUSHES ACROSS THE AREA. VERY GUSTY SHOWERS ARE POSSIBLE
WEDNESDAY NIGHT WHICH COULD PROMPT A SPECIAL MARINE WARNING OR TWO.
ALTHOUGH THURSDAY'S GUSTS GENERALLY TOP OUT AROUND 30 KNOTS, THE
STRENGTH OF THE SYSTEM CERTAINLY SUGGESTS GALES ARE POSSIBLE.
FIRE WEATHER
RH WILL RECOVER TO 80 TO 100 PERCENT TONIGHT, EXCEPT FOR
ELEVATIONS ABOVE 2000 FEET WHICH LIKELY REMAIN BETWEEN 30 AND 60
PERCENT. RH WILL DROP TO 35 TO 45 PERCENT SUNDAY AFTERNOON,
EXCEPT MUCH LOWER OVER 2000 FEET ELEVATION GIVEN DRY AIR ALOFT.
WINDS WILL BE VERY LIGHT UNDER HIGH PRESSURE, HOWEVER, LESS THAN
10 MPH OUT OF THE NORTHWEST BECOMING SOUTHWEST SUNDAY AFTERNOON.
THE NEXT POTENTIAL FOR WIDESPREAD WETTING RAIN IS MID WEEK.
TIDES/COASTAL FLOODING
AS OFFSHORE FLOW BECOMES LIGHTER AND EVENTUALLY SOUTHWEST
THROUGH SUNDAY, WATER LEVELS ARE EXPECTED TO REBOUND. IN FACT,
THEY WERE ALREADY SHOWING SOME SIGNS OF THIS AS OF MID SATURDAY
AFTERNOON. THIS RISE IN WATER LEVELS COULD PUSH VULNERABLE SITES
SUCH AS ANNAPOLIS AND WASHINGTON DC SW WATERFRONT TOWARD MINOR,
ESPECIALLY FOR THE ASTRONOMICALLY HIGHER EVENING TIDES THE NEXT
COUPLE OF DAYS.
LWX WATCHES/WARNINGS/ADVISORIES
DC...NONE.
MD...NONE.
VA...NONE.
WV...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 11 PM EST THIS EVENING FOR ANZ530-
536-538-542.
SMALL CRAFT ADVISORY UNTIL 6 AM EST SUNDAY FOR ANZ531>534-537-
539>541-543.
SMALL CRAFT ADVISORY UNTIL 6 PM EST THIS EVENING FOR ANZ535.
SYNOPSIS...DHOF
NEAR TERM...DHOF
SHORT TERM...DHOF
LONG TERM...BRO
AVIATION...BRO/DHOF
MARINE...BRO/DHOF
FIRE WEATHER...DHOF
TIDES/COASTAL FLOODING...DHOF
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