Area Forecast Discussion
Issued by NWS Wilmington, NC

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000
FXUS62 KILM 010244
AFDILM

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WILMINGTON NC
1044 PM EDT FRI OCT 31 2014

.SYNOPSIS...
A POWERFUL COLD FRONT WILL CROSS THE REGION SATURDAY MORNING. LOW
PRESSURE WILL STRENGTHEN OVER EASTERN NORTH CAROLINA SATURDAY...
RAPIDLY INTENSIFYING AS IT MOVES OFFSHORE SATURDAY NIGHT AND SUNDAY.
COLD CANADIAN HIGH PRESSURE WILL BRING THE COLDEST TEMPERATURES OF
THE SEASON SATURDAY THROUGH SUNDAY NIGHT. TEMPERATURES WILL
MODERATE BEGINNING MONDAY AS HIGH PRESSURE MOVES SLOWLY OFFSHORE.

&&

.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
AS OF 1030 PM FRIDAY...WAVE OF CONVECTIVE PRECIP THAT BLEW UP IN THE
FOOTHILLS AND WESTERN PIEDMONT EARLIER THIS EVENING IS APPROACHING
I-95 NOW...ALTHOUGH IN A WEAKENED STATE. ISENTROPIC FIELDS OFF THE
MODELS SHOW THE REGION SHOULD ACTUALLY BE EXPERIENCING WEAK
DOWNGLIDE THROUGH THE 290-295K THETA LAYER...HOWEVER THERE IS SMALL
POSITIVE BUOYANCY PROVIDED BY COOLING MID-LEVEL TEMPERATURES AHEAD
OF THE UPPER LOW. AS THIS PRECIP MOVES EAST IT SHOULD STEADILY
WEAKEN BUT SHOULD STILL REACH THE SC COAST BY 2 AM AND THE NC COAST
BY 4 AM. RADIATIONAL COOLING IN THE CLEAR SKIES OUT AHEAD OF THIS
PRECIP HAS DROPPED TEMPERATURES DOWN TO 46 AT BURGAW AND 48 IN
WHITEVILLE. AFTER ANOTHER 1-2 DEGREE TEMPERATURE DROP LOOK FOR
TEMPERATURE CURVES TO RISE LATE DUE TO CLOUD COVER.

&&

.SHORT TERM /6 AM SATURDAY MORNING THROUGH SUNDAY NIGHT/...
AS OF 300 PM FRIDAY...WINDY AND CHILLY WEATHER EXPECTED FOR SAT
WITH AT LEAST A LIKELIHOOD OF SHOWERS. A COLD FRONT WILL BE MOVING
ACROSS THE AREA SAT MORNING...USHERING IN A VERY CHILLY AIRMASS.
THIS WILL PREVENT TEMPS FROM RISING MUCH THROUGH THE DAY AND WE
EXPECT THE DIURNAL RANGE WILL BE UNSEASONABLY SMALL.

AN UPPER LOW AND ITS ASSOCIATED LIFT AND ENERGY WILL BE MOVING
ACROSS THE FORECAST AREA ON SAT. A SECONDARY AREA OF SURFACE LOW
PRESSURE IS EXPECTED TO STRENGTHEN OFFSHORE OF NORTH CAROLINA ON SAT
IN RESPONSE TO THE STRONG ENERGY ALOFT. THIS LOW WILL BECOME
DOMINATE AS IT MOVES RAPIDLY TO THE NORTHEAST AND AWAY FROM THE AREA
SAT NIGHT. AS THE PRESSURE GRADIENT SIGNIFICANTLY TIGHTENS...WIND
SPEEDS IN THE 1 TO 2 KFT LAYER WILL INCREASE TO 45 TO 50 KT. NW
WINDS AT THE SURFACE WILL INCREASE TO 25 TO 35 MPH WITH THE
STRONGEST WINDS EXPECTED DURING THE LATER HALF OF THE AFTERNOON AND
SAT NIGHT. WIND GUSTS UP TO 40 TO 45 MPH ARE EXPECTED...HIGHEST
ACROSS THE NORTH CAROLINA COAST IN CLOSEST PROXIMITY TO THE
STRENGTHENING AREA OF LOW PRESSURE. PORTIONS OF THE FORECAST AREA
MAY REQUIRE A WIND ADVISORY WITH LATER FORECASTS. STRONG WINDS WILL
ADD TO THE CHILL AS HIGHS ON SAT ARE ONLY EXPECTED TO REACH THE
UPPER 40S TO LOWER 50S WITH MID 50S ALONG COASTAL NORTH CAROLINA.
LOWS SAT NIGHT WILL FALL TO THE MID 30S INLAND TO UPPER 30S AND
LOWER 40S NEARER TO THE COAST. ALTHOUGH WINDS OVERNIGHT SAT WILL BE
DIMINISHING...THEY ARE NOT EXPECTED TO GO LIGHT AND SO WE DO NOT
EXPECT A FROST EXCEPT PERHAPS IN THE MOST WIND PROTECTED INLAND
AREAS NEAR SUNRISE SUN.

CHILLY AIR ALOFT ON SAT...AROUND MINUS 25 DEG C...WILL HELP TO
INCREASE THE INSTABILITY. DRY AIRMASS WILL MOISTEN BELOW 25 KFT SAT
AFTERNOON. COUPLE THE INCREASING MOISTURE WITH THE STRONG DYNAMICS
AND WE SHOULD BE ABLE TO WRING OUT NUMEROUS TO WIDESPREAD SHOWERS.
GIVEN THE BREVITY AND RATHER SHALLOW NATURE OF THE MOISTURE
RETURN...EXPECT RAINFALL AMOUNTS WILL NOT EXCEED A QUARTER OF AN
INCH AND MOST PLACES MAY NOT EXCEED A TENTH OF A INCH. SOME OF THE
SHOWERS THAT MANAGE TO GAIN SLIGHTLY MORE DEPTH MAY BE ACCOMPANIED
BY GRAUPEL. WILL NOT INCLUDE THUNDERSTORMS AT THIS TIME GIVEN WE
EXPECT THE CONVECTION TO BE SHALLOW. MIXED LAYER CAPE VALUES WILL BE
AT OR BELOW 200 J/KG...EVEN AT THE COAST. HOWEVER...IT IS A VERY
DYNAMIC SYSTEM AND SO AN ISOLATED LIGHTNING STRIKE CAN NOT BE RULED
OUT. THE RISK FOR THUNDERSTORMS WILL BE HIGHER ACROSS THE WARMER
OFFSHORE WATERS.

COLD HIGH PRESSURE WILL SLOWLY BUILD ACROSS THE EASTERN CAROLINAS IN
THE WAKE OF INTENSE LOW PRESSURE SUN AND SUN NIGHT. THIS WILL SET
THE STAGE FOR ANOTHER UNSEASONABLY COLD DAY AND A POSSIBLE FREEZE IN
MOST LOCATIONS SUN NIGHT. WINDS WILL BE STRONGEST IN THE MORNING AND
THEN DECREASE AS THE PRESSURE GRADIENT CONTINUES TO RELAX. HIGHS ON
SUN...EVEN WITH MAINLY SUNNY SKIES...WILL BE IN THE LOWER TO MID
50S. LOWS WILL BE VERY NEAR 32 DEGREES EXCEPT FOR POSSIBLY MID 30S
VERY NEAR THE COAST AND AT THE BEACHES.

&&

.LONG TERM /MONDAY THROUGH FRIDAY/...
AS OF 300 PM FRIDAY...THE EXTENDED WILL FEATURE A LOT OF AMPLITUDE
AT THE MID LEVELS FOR MOST OF THE PERIOD. EARLY ON...SHARP RIDGING
WILL MOVE ACROSS THE MISSISSIPPI VALLEY AND THEN OFF THE SOUTHEAST
COAST AS DEEP TROUGHING DEVELOPS ACROSS THE SOUTHWEST THAT
EVENTUALLY CUTS OFF. BY THURSDAY A SHORTWAVE ORIGINATING FROM THE
NORTHWEST WILL MOVE ACROSS WITH A DRY FRONT AT THE SURFACE. PRIOR
TO THIS AND JUST BEYOND...SURFACE HIGH PRESSURE WILL PREVAIL.
THERE IS LITTLE TO NO POPS IN THE FORECAST...JUST SLIGHT CHANCE
WITH THIS FRONT LATE WEDNESDAY AND THURSDAY. TEMPERATURE TRENDS
SHOW A SLOW MODERATING TREND FOR MONDAY THROUGH THURSDAY WITH
VALUES BELOW CLIMATOLOGY FOR THE MOST PART ESPECIALLY MORNING
LOWS. HIGHS DO CLIMB BACK INTO THE 70S WEDNESDAY AND THURSDAY
BEFORE FALLING BACK SLIGHTLY FRIDAY.

&&

.AVIATION /00Z SATURDAY THROUGH WEDNESDAY/...
AS OF 00Z...EXPECT VFR THROUGH THE VALID TAF PERIOD WITH INCREASING
CHANCES FOR WIDESPREAD SHOWERS AND GUSTY WINDS ON SATURDAY.

LATEST RADAR LOOP DEPICTS A FEW SHOWERS JUST TO THE WEST OF OUR
FORECAST AREA WHICH ARE GRADUALLY TRACKING EASTWARD. AS A
RESULT...HAVE INTRODUCED VCSH THROUGH THE EVENING HOURS FOR THE
INLAND SITES...WHILE THE COASTAL SITES WILL STAY DRY. OTHERWISE SKY
COVERAGE WILL INCREASE TO SCT/BKN/OVC THROUGH THE OVERNIGHT HOURS
WITH LIGHT NORTHERLY WINDS. LATE OVERNIGHT INTO THE EARLY MORNING
HOURS...VCSH POSSIBILITY EXTENDS TO THE COAST...AND AFTER DAYBREAK
VCSH CONTINUES AT ALL SITES WITH SHRA ACTIVITY INCREASING INTO THE
AFTERNOON HOURS. COULD NOT RULE OUT A BRIEF PERIOD OF MVFR DUE TO
HEAVY RAINFALL SATURDAY AFTERNOON...BUT FOR NOW ANTICIPATE VFR
THROUGH THE DAY. AS FOR WINDS...NORTH-NORTHWEST WINDS IN THE MORNING
HOURS WILL INCREASE AND BECOME WINDY TO GUSTY...AOB 15 KTS BY THE
AFTERNOON WITH GUSTS UP TO 25 KTS POSSIBLE.

EXTENDED OUTLOOK...BREEZY TO WINDY CONDITIONS TO PERSIST INTO SUNDAY
AFTER LOW PRESSURE DEVELOPS OFF THE CAROLINA COAST...AND
ACCELERATES TO THE NE. VFR FOR MONDAY AND TUESDAY AS THE CENTER OF
STRONG HIGH PRESSURE MOVES OVERHEAD. LIGHT MORNING FOG POSSIBLE
WEDNESDAY.

&&

.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 1030 PM FRIDAY...SURFACE ANALYSIS AT 10 PM SHOWS A BAGGY AREA
OF LOW PRESSURE DEVELOPING AT THE SURFACE FROM THE NC FOOTHILLS
SOUTHEASTWARD TO THE SOUTH CAROLINA COAST. THIS IS THE EARLY STAGE
OF WHAT WILL BECOME A POWERFUL LOW TOMORROW MOVING OFF THE NC COAST.
INCREASING WESTERLY WINDS SHOULD DEVELOP BEHIND THIS LOW...POSSIBLY
STARTING ALONG THE SC COAST SOUTH OF MYRTLE BEACH BEFORE
SUNRISE...BUT LIKELY WAITING UNTIL DURING THE DAY SATURDAY TO AFFECT
AREAS OF NORTH OF MYRTLE BEACH. VERY FEW CHANGES WERE NEEDED TO THE
FORECAST WITH THIS LATE EVENING UPDATE.

SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
AS OF 300 PM FRIDAY...A GALE WARNING IS IN EFFECT SAT AFTERNOON
AND NIGHT WITH A PERIOD OF SMALL CRAFT ADVISORY CONDITIONS
EXPECTED INTO SUN. AS LOW PRESSURE STRENGTHENS OFF THE NORTH
CAROLINA COAST AND THE PRESSURE GRADIENT TIGHTENS...SUSTAINED
WINDS SHOULD REACH GALE FORCE WITH GUSTS AS HIGH AS 40 TO 45 KT.
THE STRONGEST WINDS ARE EXPECTED LATER SAT AFTERNOON AND
ESPECIALLY SAT NIGHT. SEAS WILL EXCEED 6 FT ACROSS PORTIONS OF THE
WATERS BY MIDDAY SAT AND UP TO 6 TO 8 FT SAT NIGHT. NEAR
SHORE...SEAS WILL BE LOWER GIVEN THE STRONG OFFSHORE FLOW. IN THE
WAKE OF INTENSE LOW PRESSURE...WINDS AND SEAS WILL SUBSIDE SUN AND
SUN NIGHT. A BLOW OUT TIDE MAY OCCUR WITH LOW TIDE SAT EVE AND
AGAIN SUN MORNING.

LONG TERM /MONDAY THROUGH WEDNESDAY/...
AS OF 300 PM FRIDAY...A FEW HOURS OF STRONGER NORTHWEST WINDS
WILL CONTINUE MONDAY BEFORE SETTLING DOWN TO ESSENTIALLY LIGHT AND
VARIABLE BY DAYS END. THIS AS HIGH PRESSURE SETTLES OVERHEAD. THE
LIGHT WINDS WILL CONTINUE FOR THE REMAINDER OF THE PERIOD AS HIGH
PRESSURE IS SLOW TO MOVE AND THE AXIS ELONGATES TO KEEP WINDS
BENIGN. SEAS WILL MIRROR THE LIGHT WINDS WITH ONE TO TWO FEET
THROUGH THE PERIOD.

&&

.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...GALE WARNING FROM NOON EDT SATURDAY TO 6 AM EST SUNDAY FOR
     AMZ250-252-254-256.

&&

$$

NEAR TERM...TRA
SHORT TERM...RJD
LONG TERM...SHK
AVIATION...SGL





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