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000
FXUS62 KILM 062037
AFDILM

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WILMINGTON NC
337 PM EST THU MAR 6 2014

.SYNOPSIS...
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LOW PRESSURE WILL CROSS FLORIDA THIS EVENING AND TURN
NORTHEASTWARD ALONG THE GEORGIA AND SOUTH CAROLINA COAST TONIGHT. UP
TO TWO INCHES OF RAIN AND WINDY CONDITIONS ARE EXPECTED THROUGH
TONIGHT. THE LOW WILL MOVE AWAY FROM THE NORTH CAROLINA COAST FRIDAY
AFTERNOON. HIGH PRESSURE WILL BUILD IN FOR THE WEEKEND WITH MUCH
WARMER AND DRIER WEATHER EXPECTED INTO THE MIDDLE OF NEXT WEEK.
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&&

.NEAR TERM /THROUGH TONIGHT/...
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AS OF 3 PM THURSDAY...DEEPENING LOW PRESSURE IS CROSSING FLORIDA
THIS AFTERNOON AND SHOULD HOOK NORTHEASTWARD THIS EVENING...
FOLLOWING THE WESTERN EDGE OF THE GULF STREAM CURRENT ALONG THE
GEORGIA AND SOUTH CAROLINA COAST TONIGHT. BY 12Z/7AM EST FRIDAY THE
SURFACE LOW SHOULD BE SITUATED ABOUT 100 MILES SOUTHEAST OF CAPE
FEAR. THE UPPER LEVEL LOW ACROSS MISSISSIPPI IS STILL DIGGING
SOUTHEASTWARD AND SHOULD REACH THE BOTTOM OF ITS ARC IN SOUTHERN
ALABAMA AROUND MIDNIGHT...THEN TURNING NORTHEASTWARD TOO LATE
TONIGHT.

THIS SYSTEM WILL BRING A VARIETY OF WEATHER IMPACTS TO THE
CAROLINAS. HEAVY RAINFALL WILL BE THE RESULT OF STRENGTHENING
ISENTROPIC LIFT AS WARM SUBTROPICAL AIR ADVECTED NORTHWARD FROM THE
BAHAMAS IS FORCED TO RISE HUNDREDS OF MILLIBARS ACROSS THE FRONTAL
INVERSION WELL OFFSHORE. AIR ALONG THE 295K ISENTROPIC SURFACE
ORIGINATES A FEW THOUSAND FEET ALOFT OVER FLORIDA BUT RISES TO THE
700 MB LEVEL (10000 FEET UP) AS IT PASSES OVER THE CAROLINAS
TONIGHT. THIS WILL RELEASE A TREMENDOUS AMOUNT OF MOISTURE AS HEAVY
RAINFALL...WITH STORM-TOTAL QPF POSSIBLY EXCEEDING TWO INCHES ALONG
THE COAST AND 1.5 INCHES INLAND.

STRONG SURFACE WINDS OF 25-35 MPH MAY GUST OVER 40 MPH NEAR THE
COAST TONIGHT. THESE WINDS COULD DISLODGE BROKEN BRANCHES STILL
HANGING UP IN TREES FROM THE BIG ICE STORM LAST MONTH. FORTUNATELY
THE BOUNDARY LAYER SHOULD REMAIN STABLE WITH LITTLE POTENTIAL FOR
CONVECTIVE MIXING OF STRONGER WINDS DOWN FROM ALOFT. THAT`S A VERY
GOOD THING SINCE 925 MB WIND SPEEDS MAY REACH 50-60 KNOTS DURING THE
STRONGEST PORTION OF THE WARM ADVECTION ALOFT.

AMONG MODEL GUIDANCE THE 12Z GFS IS PREFERRED OVER THE 12Z NAM WITH
REGARDS TO THE MOVEMENT OF THE SURFACE LOW OFFSHORE TONIGHT. THE NAM
AND MANY OF ITS ENSEMBLE MEMBERS FOR THE PAST COUPLE DAYS HAVE BEEN
CONSISTENTLY TURNING THE LOW TO THE LEFT AND MOVING IT INTO THE COLD
AIR NEAR THE COAST. THE GFS AND ECMWF HAVE BEEN FARTHER EAST AND
OFFSHORE...FOLLOWING A MORE CLIMATOLOGICALLY PREFERRED TRACK. IF THE
UPPER LEVEL SYSTEM WERE TO CUT OFF TO OUR SOUTHWEST I COULD SEE THE
SURFACE MOVING FARTHER WESTWARD...BUT IN THIS CASE A STEADY EASTWARD
MOVEMENT OF THE UPPER SYSTEM SUGGESTS A MORE OFFSHORE TRACK.

FOR LOWS TONIGHT...IT`S A BATTLE BETWEEN EVAPORATIONAL COOLING EARLY
AND ADVECTION OF COOLER AIR FROM INTERIOR NORTH CAROLINA LATER
TONIGHT VERSUS STRONG WARM ADVECTION ALOFT. TEMPERATURES MAY
ACTUALLY RISE ALONG THE COAST...PARTICULARLY THE NC COAST
OVERNIGHT...BUT SHOULD FALL ELSEWHERE AS THE COLDER AIR ACROSS
INTERIOR NC DRAINS SOUTHWARD TO THE COAST.
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&&

.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
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AS OF 3 PM THURSDAY...1003MB LOW PASSING BY OFFSHORE AT THE START OF
THE PERIOD. WE AREN`T IN FAVOR OF THE CLOSER WRF TRACK AS THE LONG
RUNNING PRECIPITATION INTO THE OVERLAND WEDGE SHOULD RE-ENFORCE THE
AIRMASS AND LEAD TO HIGHER PRESSURES KEEPING THE WAVE A BIT FURTHER
OFFSHORE CLOSER TO GFS/EC TRACK. THIS KEEPS GUSTY WINDS IN THE
FORECAST THROUGH THE FIRST PART OF THE DAY. WITH THE SYNOPTIC SCALE
DRY SLOT REMAINING OFFSHORE THERE WILL ALMOST CERTAINLY STILL BE
SOME RAIN AROUND BUT WITH THE GOOD WAA AND PVA SHIFTING WELL OFF TO
OUR NORTH AND EAST THE FORCING WILL BE ON THE WANE. ADDITIONALLY
MODELS SHOW MID LEVELS DRIED OUT BY 12Z AND ONLY LOW LEVELS
REMAINING SATURATED. THUS THE QPF PROSPECTS FOR THE SHORT TERM MUCH
LESSER THAN THOSE OF THE NEAR TERM. WRAPAROUND MOISTURE MAY BE SLOW
TO DEPART HEADING INTO FRIDAY NIGHT MAINLY IN THE FORM OF LINGERING
CLOUDINESS BUT THE OCCASIONAL SPRINKLE WILL BE HARD TO RULE OUT. AS
IT QUICKLY EXITS BY SATURDAY TEMPERATURES WILL QUICKLY BACK TO
CLIMO...AFTERNOON HIGHS CLIMBING WELL INTO THE 60S. SATURDAY NIGHT
ALSO APPEARS SEASONABLE WITH LITTLE CLOUD COVER.
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&&

.LONG TERM /SUNDAY THROUGH THURSDAY/...
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AS OF 3 PM THURSDAY...DRY COLD FRONT WILL DROP IN FROM THE NORTH
LATE SUN INTO MON FOLLOWED BY BRIEF WEAK COLD ADVECTION. MID LEVEL
MOISTURE WILL PRODUCE SOME CLOUD AS THE FRONT PASSES BUT LACK OF
DYNAMICS AND DEEPER MOISTURE KEEPS PRECIP CHANCES CLOSE TO ZERO.
TEMPERATURES EARLY IN THE PERIOD WILL REMAIN NEAR TO ABOVE
CLIMO...SHOWING JUST HOW WEAK THE COLD ADVECTION BEHIND THE SUN
NIGHT FRONT IS.

DEEP WESTERLY FLOW AND SOUTHERLY LOW LEVEL FLOW AHEAD OF A COMPLEX
SYSTEM MOVING INTO THE CAROLINAS MID WEEK WILL KEEP TEMPS ABOVE
CLIMO TUE AND WED. PRECIP CHANCES REMAIN ELEVATED WED AND THU AS
COMPLEX SYSTEM IMPACTS THE EASTERN CONUS. ALTHOUGH THERE ARE SOME
SIGNIFICANT DIFFERENCES BETWEEN THE GFS/ECMWF MID LEVEL
PATTERN...MAINLY LATER IN THE PERIOD...BOTH MAINTAIN ELEVATED PRECIP
CHANCES WED. THE BIGGEST DIFFERENCE IS THE AMOUNT OF AMPLIFICATION
WED/THU AND THE EASTWARD PROGRESSION OF THE MID LEVEL TROUGH. THIS
HAS IMPLICATIONS ON THE POP FORECAST FOR THU. ECMWF SOLUTION IS
SLOWER AND PRECIP LINGERS THROUGH THU. INHERITED FORECAST CARRIED
SLIGHT CHC/LOW CHC POP FOR THU AND GIVEN THE UNCERTAIN ON D7 WILL
NOT MAKE CHANGES. EITHER SOLUTION ENDS UP WITH TEMPS WELL BELOW
CLIMO FOR THE END OF THE PERIOD...THOUGH AS EXPECTED THE
WEAKER/FASTER GFS IS SLIGHTLY WARMER.
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&&

.AVIATION /18Z THURSDAY THROUGH TUESDAY/...
AS OF 18Z...RADAR IMAGERY SHOWS A SWATH OF RAIN SPREADING NORTHWARD
ACROSS OUR CWA THIS AFTERNOON...WITH THE HEAVIEST PCPN FOCUSED ALONG
THE COAST AND OFFSHORE. EXPECT MORE WIDESPREAD RAIN THROUGH THE REST
OF TODAY WITH MVFR CIGS DEVELOPING AT ALL TERMS BEFORE 00Z FRIDAY.
IFR CIGS ARE LIKELY TO DEVELOP FIRST AT THE COASTAL SITES...AND
TEMPO IFR IS CERTAINLY POSSIBLE BEFORE 00Z AT KMYR/KCRE/KILM. RA/+RA
THIS EVENING AND TONIGHT COULD PRODUCE PERIODS OF IFR VSBYS AS WELL.
GUSTY NORTH-NORTHEAST WINDS WILL PERSIST THROUGH THE PERIOD...15-20
KTS WITH GUSTS OF 30+ KTS POSSIBLE TONIGHT. WIDESPREAD IFR CIGS ARE
INCREASINGLY LIKELY OVERNIGHT...WITH HIGHEST CONFIDENCE ALONG THE
COAST. FCST SOUNDINGS AND GUIDANCE INDICATE IFR WILL PERSIST THROUGH
THE REST OF THE PERIOD...EVEN AS RAIN CHANCES DIMINISH INTO FRIDAY
AFTERNOON.

EXTENDED OUTLOOK...MVFR/IFR CIGS POSSIBLE LATE FRIDAY INTO EARLY
SATURDAY. OTHERWISE EXPECT VFR THROUGH TUESDAY.

&&

.MARINE...
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NEAR TERM /THROUGH TONIGHT/...
AS OF 3 PM THURSDAY...DEEPENING LOW PRESSURE IS CROSSING THE CENTRAL
FLORIDA PENINSULA THIS AFTERNOON. THIS LOW IS EXPECTED TO TURN
NORTHEAST THIS EVENING...FOLLOWING THE WESTERN EDGE OF THE GULF
STREAM ALONG THE GEORGIA AND SOUTH CAROLINA COAST AND REACHING A
POINT ABOUT 100 MILES SOUTHEAST OF CAPE FEAR BY DAYBREAK FRIDAY. A
POWERFUL PRESSURE GRADIENT BETWEEN THIS LOW AND ARCTIC HIGH PRESSURE
OVER NEW ENGLAND WILL PRODUCE SUSTAINED GALE-FORCE WINDS
TONIGHT...WITH GUSTS POTENTIALLY REACHING 40 KNOTS SOUTH AND EAST OF
CAPE FEAR. SEAS CURRENTLY MEASURED AT 11 FT AT FRYING PAN SHOALS AND
9 FEET AT THE CAPE FEAR HARBOR BUOY WILL LIKELY BUILD BY ANOTHER 3-5
FEET TONIGHT.

WHILE MANY OF OUR GALE WARNINGS LOCALLY ARE FOR GUSTS AND OFTEN IN
OFFSHORE FLOW BEHIND A DEPARTING LOW...THIS IS A MUCH STRONGER AND
MORE DANGEROUS EVENT WITH THE POTENTIAL FOR TROPICAL STORM-LIKE
IMPACTS FROM THE BEACHES OUT INTO THE OCEAN.



SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
AS OF 3 PM THURSDAY...GALES AND LARGE WAVES CONTINUE AT THE START OF
THE PERIOD. THERE IS A MODEL SOLUTION THAT BRINGS THE LOW UP THE
COAST RATHER THAN THE CURRENTLY FAVORED TRACK WHICH IS ALMOST 100 NM
OFFSHORE. THE LOW WILL MOVE OFF TO THE NE FRIDAY NIGHT BUT NOT BE
ACCELERATING AS IS MORE TYPICAL OF SUCH SYSTEMS. SO...WINDS WILL BE
A BIT SLOW TO ABATE AND GALE WARNING LIKELY LOWERED TO ADVISORY FOR
MOST OR ALL NIGHT. IMPROVEMENT ON SATURDAY AS THE WINDS BACK IN
DIRECTION AND DECREASE IN SPEED. THERE WILL BE SOME BACKSWELL FROM
THE SYSTEM HOWEVER AS IT DEEPENS AND GROWS IN SIZE WELL OFF THE NEW
ENGLAND COAST.

LONG TERM /SUNDAY THROUGH TUESDAY/...
AS OF 3 PM THURSDAY...LIGHT WESTERLY FLOW SUN WILL BECOME NORTHWEST
SUN NIGHT FOLLOWING PASSAGE OF WEAK COLD FRONT. DURATION OF
NORTHWEST FLOW WILL BE SHORT AND LACK OF COLD ADVECTION OR PRESSURE
GRADIENT WILL KEEP SPEEDS UNDER 10 KT. WINDS BACK TO SOUTHWEST LATER
MON AND MON NIGHT AS WEAK BUT LARGE SURFACE TROUGH MOVES EAST ACROSS
THE GREAT LAKES AND NEW ENGLAND. GRADIENT BECOMES A LITTLE MORE
DEFINED MON NIGHT INTO TUE...ENOUGH TO PUSH SPEEDS INTO THE 10 TO 15
KT RANGE. LATE IN THE PERIOD GRADIENT STARTS TO TIGHTEN UP AS SYSTEM
TO THE WEST APPROACHES. SOUTHWEST FLOW CONTINUES BUT ON THE HIGH END
OF THE 10 TO 15 KT RANGE. SEAS 2 TO 3 FT SUN AND MON BUILD BY A FOOT
OR SO FOR TUE AS SOUTHWEST FLOW PICKS UP.
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&&

.TIDES/COASTAL FLOODING...
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AS OF 3 PM THURSDAY...TONIGHT`S OFFSHORE GALE WILL BRING A VARIETY
OF WEATHER-RELATED THREATS TO THE BEACHES. NORTHEAST WINDS 30-40 MPH
(AND EVEN STRONGER OFFSHORE) WILL BRING TREMENDOUS WAVE ENERGY INTO
THE SURF ZONE. A LARGE MIX OF WAVE PERIODS (5 TO 9 SECONDS) WILL NOT
PLEASE ANYONE IN THE SURFING COMMUNITY...BUT BREAKING WAVE HEIGHTS
UP TO EIGHT FEET NECESSITATE AN ADVISORY.

ALTHOUGH WE ARE ALMOST ONE WEEK PAST THE NEW MOON AND TIDAL RANGES
ARE NOT ESPECIALLY HIGH...STRONG NORTHEAST WINDS COULD PRODUCE A
STORM SURGE AS HIGH AS 2.0 TO 2.5 FEET OVERNIGHT. WHEN ADDED TO THE
ASTRONOMICAL TIDES AROUND MIDNIGHT...WE ARE ISSUING A COASTAL FLOOD
ADVISORY FOR MINOR COASTAL FLOODING. THE BIGGER ISSUE MAY ACTUALLY
BE BEACH EROSION RATHER THAN ACTUAL INUNDATION AS SO MUCH WAVE
ENERGY IS DIRECTED ONTO THE UPPER BEACH AND DUNE EDGES DURING
TONIGHT`S TIDE HIGH.

LOCATION              ASTRO TIDE   ESTOFS SURGE MODEL   WATER LEVEL

WRIGHTSVILLE BEACH       4.0 FT  +        2.5 FT     =  6.5 FT MLLW
MYRTLE BEACH             5.0 FT  +        2.1 FT     =  7.1 FT MLLW

OFFICIAL FLOOD STAGE AT WRIGHTSVILLE BEACH IS 6.0 FT MLLW...AND 7.5
FEET AT MYRTLE BEACH. HIGH TIDE SHOULD OCCUR AROUND MIDNIGHT.

IT IS WORTH NOTING THE ETSURGE MODEL IS NOT AS AGGRESSIVE WITH
TONIGHT`S STORM SURGE. GIVEN THE MAGNITUDE OF THE WIND STRESS ACROSS
THE OCEAN SURFACE AND THE PRESENCE OF AN WATER LEVEL ANOMALY ALREADY
MEASURED AT +0.5 TO +1.0 FEET THIS AFTERNOON...THE HIGHER ESTOFS
GUIDANCE IS PREFERRED AND MAY EVEN BE EXCEEDED ALONG THE SOUTH
CAROLINA COAST WHERE A SLIGHT ONSHORE WIND COMPONENT WILL EXIST.
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&&

.ILM WATCHES/WARNINGS/ADVISORIES...
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SC...HIGH SURF ADVISORY FROM 7 PM THIS EVENING TO 2 PM EST FRIDAY
     FOR SCZ054-056.

     COASTAL FLOOD ADVISORY FROM 11 PM THIS EVENING TO 2 AM EST
     FRIDAY FOR SCZ054-056.

NC...HIGH SURF ADVISORY FROM 7 PM THIS EVENING TO 2 PM EST FRIDAY
     FOR NCZ106-108-110.

     COASTAL FLOOD ADVISORY FROM 11 PM THIS EVENING TO 2 AM EST
     FRIDAY FOR NCZ106-108-110.

MARINE...GALE WARNING UNTIL 1 PM EST FRIDAY FOR AMZ250-252-254-256.
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&&

$$

NEAR TERM...TRA
SHORT TERM...MBB
LONG TERM...III
AVIATION...BJR
TIDES/COASTAL FLOODING...TRA