733
FXUS62 KILM 120544
AFDILM
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WILMINGTON NC
1244 AM EST TUE NOV 12 2019
SYNOPSIS
SHOWERS ON TUESDAY WILL PRECEDE A STRONG COLD AIRMASS THAT
ARRIVES TUESDAY NIGHT INTO WEDNESDAY. THURSDAY AND FRIDAY WILL
NOT BE A COLD BUT STILL A BIT BELOW NORMAL. LATE WEEK RAIN
CHANCES WILL BE ASSOCIATED WITH LOW PRESSURE THAT DEVELOPS AND
MOVES TO THE NORTHEAST ON FRIDAY, THEN FOLLOWED BY ANOTHER THAT
FORMS AND STALLS OVER THE WEEKEND.
UPDATE
PUBLIC:
HAVE UPDATED SKY CONDITIONS TO INCLUDE THE STRATOCU DECK
DEVELOPING AND MOVING N-NE INTO THE ILM SC CWA WHICH WILL
OVERSPREAD INTO THE ILM NC CWA. ABOVE THE SC DECK WILL CONTINUE
TO SEE THIN CIRRUS MOVE ACROSS WHICH WILL BECOMING MORE OPAQUE
AS THE NIGHT PROGRESSES. THIS WILL LIKELY RESULT IN MIN TEMPS
ACTUALLY OCCURRING AROUND OR JUST AFTER MIDNIGHT, FOLLOWED BY
STEADY TREND OR EVEN RISING TEMPS, ESPECIALLY CLOSER TO THE
IMMEDIATE COAST. NO CHANGES TO THE ONSET OF PCPN.
MARINE:
SOME TWEAKING OF WINDSPEEDS APPLIED TO THE FORECAST. TAKING THE
LATEST WIND TRENDS AND MESHING THEM WITH THE PRE-DAWN TUE
FORECAST. OTHERWISE, NO CHANGES TO SEAS AND THE ONSET OF GALES.
NEAR TERM /THROUGH TUESDAY NIGHT/
IN THE VERY NEAR TERM, CONTINUING CIRRUS CLOUDS WILL BE JOINED BY
LOWER LEVEL STRATOCUMULUS OFF THE OCEAN, AFFECTING THE CAPE FEAR
AREA AFTER MIDNIGHT. DEEPER MOISTURE WILL ALSO ARRIVE FROM THE WEST
INTO THE PEE DEE REGION VERY LATE TONIGHT, WITH THE BULK OF ANY RAIN
POTENTIAL HOLDING OFF UNTIL DURING THE DAY TUESDAY. MODELS ALL SEEM
TOO QUICK TO BRING DEWPOINTS UP THIS AFTERNOON, SO I'M DOWNPLAYING
SHOWER CHANCES TONIGHT. MOS LOW TEMPS LOOK GENERALLY TOO WARM GIVEN
AT LEAST 4-6 HOURS OF RADIATIONAL COOLING BEFORE CLOUDS THICKEN UP,
AND I'M FORECASTING AROUND 50 INLAND AND LOW-MID 50S ALONG THE COAST.
1046 MB ARCTIC HIGH PRESSURE OVER THE HIGH PLAINS WILL PUSH A STRONG
FRONT ACROSS THE CAROLINAS ON TUESDAY. THE FRONT SHOULD COME THROUGH
IN TWO PIECES: AN INITIAL SHIFT TO NORTHWEST WINDS ROUGHLY
COINCIDENT WITH START OF THE RAIN, THEN A SHIFT TO STRONG NORTH
WINDS AND A SHARP TEMPERATURE FALL REACHING I-95 AROUND 1 PM AND THE
COAST BETWEEN 3-4 PM. A NARROW BAND OF DEEP MOISTURE ORIGINATING
FROM THE TROPICAL PACIFIC AND GULF OF MEXICO WILL MOVE IN AHEAD OF
THE FRONT AND SHOULD BRING A 3-6 HOUR RAINFALL EVENT WITH QPF
GENERALLY IN THE 1/4 TO 1/2 INCH RANGE. PRECIP SHOULD END A COUPLE
HOURS AFTER THE FRONTAL PASSAGE WHEN LIFT ALONG THE 295K-305K
ISENTROPIC SURFACES TURNS NEGATIVE.
THE INCOMING ARCTIC AIRMASS IS QUITE SHALLOW, ONLY EXTENDING UP
ABOUT 2500 FEET IN DEPTH. WINDS 1000-2000 FEET AGL SHOULD BE STRONG
ENOUGH GIVEN STEEP LOW LEVEL THERMAL PROFILES IN THE COLD ADVECTION
FOR GUSTS OF 25 MPH TO OCCUR FOR MOST OF TUESDAY NIGHT. THIS SHOULD
BE THE FIRST FREEZE EVENT FOR THE COASTAL COUNTIES WHICH HAVE NOT
YET EXPERIENCED SUB-FREEZING TEMPS THIS SEASON, AND A FREEZE WATCH
HAS BEEN ISSUED. MY FORECAST LOWS ARE ON THE UPPER EDGE OF MOS
GUIDANCE, PARTICULARLY AT THE COAST, GIVEN STEEP MIXING PROFILES
EXPECTED ALL NIGHT.
SHORT TERM /WEDNESDAY THROUGH WEDNESDAY NIGHT/
HIGHS WEDNESDAY IN THE MID 40S A GOOD 10 DEGREES BELOW
CLIMATOLOGY...FOR THE HEART OF WINTER. SHALLOW COLD AIR POURING
INTO THE REGION AT A DEPTH OF JUST 2500FT MAKING FOR SOME
IMPRESSIVE/ODD FORECAST SOUNDINGS (WARMER AT 8000FT THAN AT THE
SURFACE BY EVENING). THIS SETS UP A FAIRLY CLASSIC COLD WAVE
SOUNDING WEDNESDAY NIGHT WITH A DEEP, SURFACE-BASED NEARLY
ISOTHERMAL LAYER THAT WILL FOSTER LOWS IN THE UPPER 20S INLAND
TO LOW TO MID 30S AT THE COAST.
LONG TERM /THURSDAY THROUGH MONDAY/
THE MODIFIED ARCTIC HIGH WILL BE MOVING EASTWARD QUITE RAPIDLY
THURSDAY ALLOWING FOR SOME LOW LEVEL THERMAL RECOVERY (THOUGH A
RIDGE PERSISTENT RIDGE AXIS WILL TAPER ITS EFFECTS AT THE SURFACE).
MOISTURE WILL POOL NEAR THE COAST THURSDAY IN A DEVELOPING SURFACE
TROUGH. SOUTHERN BRANCH FEATURE THEN CAUSES MODERATELY STRONG
CYCLOGENESIS OFFSHORE AND RAIN CHANCES INCREASE SUBSTANTIALLY AND
COASTAL LOCALES WILL GROW A BIT BREEZY. THE UPPER WAVE CATCHES UP TO
THE LOW LEVEL BAROCLINIC ZONE FRIDAY NIGHT INTO SATURDAY DEVELOPING
A SECOND SURFACE LOW OFFSHORE THAT WILL STALL AND OCCLUDE, POSSIBLY
TAKING ON HYBRID WARM/COLD CORE CHARACTERISTICS. GFS HAS THE WIND
FIELD EXPANDING BUT THE PRECIPITATION MOVING LARGELY OFFSHORE. HAVE
MAINTAINED POPS IN DEFERENCE TO OTHER SOLUTIONS AND PREVIOUS
FORECAST.
AVIATION /06Z TUESDAY THROUGH SATURDAY/
VFR CONDITIONS FOR THE AREA TERMINALS FOR THE NEXT 6 TO 12 HOURS
AHEAD OF A STRONG COLD FRONT APPROACHING THE REGION. EXPECTING
VISIBILITY REDUCTIONS IN MODERATE RAINFALL AND CEILING REDUCTIONS
WITH INCREASING LOW LEVEL CLOUD COVER. FLIGHT RESTRICTIONS SHOULD
BE LIFTED BETWEEN 00Z AND 03Z WEDNESDAY AS FRONT MOVES OFFSHORE.
GUSTY WINDS UP TO 30 KTS ALSO ANTICIPATED THROUGH THE NEXT 24 HOURS.
EXTENDED OUTLOOK...VFR THROUGH THE END OF THE WEEK.
MARINE
THE MAJOR CONCERN FOR MARINE WEATHER IN THE NEAR TERM IS THE PASSAGE
OF AN ARCTIC COLD FRONT TUESDAY AFTERNOON. COLD AIR BEHIND THE FRONT
WILL ARRIVE ON STRONG NORTHERLY WINDS REACHING AT LEAST 30 KNOTS
LATE TUESDAY AFTERNOON THROUGH ALL OF TUESDAY NIGHT. VIRTUALLY EVERY
12Z MODEL'S VIRTUAL SOUNDINGS SHOW 35 KNOT WINDS ONLY 1000 FEET
ABOVE THE WATER'S SURFACE TUESDAY EVENING, THE TIME WHEN FREQUENT
GALE FORCE GUSTS HAVE THE BEST POTENTIAL TO BE OCCURRING. AFTER
COLLABORATION WITH NWS MHX AND CHS, WE HAVE RAISED A GALE WARNING
EVEN THOUGH ACTUAL SUSTAINED WIND SPEEDS SHOULD REMAIN BELOW 34
KNOTS.
NORTHERLY WINDS EASE WEDNESDAY AS THE GRADIENT WEAKENS GRADUALLY.
ADVISORY FLAGS WILL BE IN EFFECT THROUGH MIDDAY OR EARLY AFTERNOON.
BY THURSDAY A SHIFT TO NE EXPECTED AS COASTAL TROUGH DEVELOPS. LOW
PRESSURE THEN DEVELOPS AND CLOSES OFF ALONG THE WELL OFFSHORE
FRONTAL BOUNDARY AND CONDITIONS WILL ONCE AGAIN WORSEN TO ADVISORY
LEVELS. THIS LOW MOVES OFF TO THE NORTHEAST BUT ANOTHER, POSSIBLY
STRONGER ONE DEVELOPS AND STALLS ON SATURDAY. GALE WARNING APPEARS
POSSIBLE.
ILM WATCHES/WARNINGS/ADVISORIES
SC...FREEZE WATCH FROM LATE TUESDAY NIGHT THROUGH WEDNESDAY MORNING
FOR SCZ054>056-058.
NC...FREEZE WATCH FROM LATE TUESDAY NIGHT THROUGH WEDNESDAY MORNING
FOR NCZ106>110.
MARINE...GALE WARNING FROM 3 PM TUESDAY TO 7 AM EST WEDNESDAY FOR
AMZ250-252-254-256.
SYNOPSIS...MBB
UPDATE...DCH
NEAR TERM...TRA
SHORT TERM...MBB
LONG TERM...MBB
AVIATION...43
MARINE...DCH/TRA/MBB
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