Area Forecast Discussion
Issued by NWS Wilmington, NC

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
000
FXUS62 KILM 302003
AFDILM

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WILMINGTON NC
ISSUED BY NATIONAL WEATHER SERVICE CHARLESTON SC
403 PM EDT THU OCT 30 2014

.SYNOPSIS...
HIGH PRESSURE WILL REST OVER THE AREA THROUGH FRIDAY BETWEEN AN
APPROACHING COLD FRONT TO THE WEST AND A WEAK AREA OF LOW PRESSURE
ALONG A RESIDUAL FRONT POSITIONED JUST OFFSHORE. A POWERFUL COLD
FRONT WILL CROSS THE REGION ON SATURDAY AS EXPANSIVE CANADIAN HIGH
PRESSURE BUILDS IN THROUGH THE REST OF THE WEEKEND. THIS AREA OF
HIGH PRESSURE WILL THEN BECOME THE DOMINANT WEATHER FEATURE THROUGH
THE FIRST HALF OF NEXT WEEK.

&&

.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
THIS EVENING AND TONIGHT...LOW STRATUS REMAINS ALONG COASTAL AREAS IN
SOUTH CAROLINA THIS EVENING BEHIND A COLD FRONT POSITIONED WELL
OFFSHORE. THESE CLOUDS WILL SLOWLY SHIFT SOUTHWARD THROUGH THIS
EVENING BUT WILL STRUGGLE TO LEAVE SOUTHERN PORTIONS OF THE FORECAST
AREA ALONG THE COAST THROUGH EARLY TONIGHT. WE SHOULD SEE ANOTHER
ROUND OF POST FRONTAL CLOUDINESS TONIGHT AS MODELS PICK UP ON
MOISTURE IN THE LOW-LVLS DURING THE APPROACH OF A MID LVL TROUGH
AXIS FROM OUR NORTHWEST AND THE DEVELOPMENT OF AN AREA OF LOW
PRESSURE ALONG THE STALLED FRONT OFFSHORE. GIVEN INCREASING CLOUD
COVER AND A SOMEWHAT TIGHTENING PRESSURE GRADIENT OVER THE AREA
LATE...HAVE BUMPED OVERNIGHT LOW TEMPS UP 1-2 DEGREES. TEMPS ARE NOW
EXPECTED TO DIP INTO THE MID 40S INLAND TO LOW/MID 50S ALONG COASTAL
AREAS. SHOULD SHOWERS DEVELOP IN ASSOCIATION WITH THE SFC LOW ALONG
THE STALLED FRONT...ACTIVITY WILL LIKELY TO REMAIN OVER COASTAL
WATERS SINCE WINDS ARE EXPECTED TO REMAIN OFFSHORE THROUGH TONIGHT.

&&

.SHORT TERM /6 AM FRIDAY MORNING THROUGH SUNDAY/...
FRIDAY AND FRIDAY NIGHT...FRIDAY WILL MAINLY BE A TRANSITIONAL DAY
AHEAD OF THE THE POWERFUL COLD FRONT THAT WILL BEGIN TO PUNCH IN TO
THE AREA FROM THE WEST LATE FRIDAY NIGHT. ALOFT...THE UPPER TROUGH
AXIS WILL SHIFT EASTWARD AND BEGIN TO AMPLIFY AS A VIGOROUS AND DEEP
UPPER LOW DIGS IN AND DIVES SOUTHWARD OUT OF THE GREAT LAKES REGION.
BY LATE FRIDAY NIGHT THE UPPER LOW SHOULD BE POSITIONED ALMOST
DIRECTLY OVER TOP OF THE SOUTHERN APPALACHIANS. AT THE
SURFACE...FRIDAY WILL SEE THE REMNANT FRONT SITTING JUST OFFSHORE
WITH A WEAK AREA OF LOW PRESSURE BEGINNING TO DEVELOP ALONG IT.
MODELS ARE CONSISTENT IN SHOWING SHOWER ACTIVITY BRUSHING THE COASTAL
WATERS AND PERHAPS BRUSHING AREAS NEAR SOUTHPORT AND ALONG
BRUNSWICK/NEW HANOVER COUNTIES. OTHERWISE...FRIDAY WILL BE QUIET
WITH HIGHS REACHING INTO THE UPPER 60S IN MOST AREAS.
OVERNIGHT...THE VERY STRONG COLD FRONT WILL BEGIN APPROACHING THE
AREA AND EVEN MOVING THROUGH FAR INLAND AREAS LATE. POPS BEGIN TO
INCREASE FROM THE WEST AFTER MIDNIGHT AS THE DEEP FORCING ASSOCIATED
WITH THE POWERFUL UPPER LEVEL DYNAMICS INCREASES. HOWEVER...THE BULK
OF ANY PRECIPITATION AND ESPECIALLY THE ARRIVAL OF THE COLD AIR WILL
BE MORE INTO THE SATURDAY TIME FRAME.

SATURDAY THROUGH SUNDAY...OVERALL IT WILL BE A CHILLY AND AT TIMES
BLUSTERY WEEKEND AS A STRONG COLD FRONT MOVES THROUGH THE AREA AND
COLD CANADIAN HIGH PRESSURE BUILDS IN. ALOFT...A POWERFUL AND DEEP
UPPER LOW WILL SWING THROUGH THE BASE OF THE DEEP UPPER TROUGH
SATURDAY MORNING AND THEN LIFT AWAY FROM THE AREA THROUGH SUNDAY. AT
THE SURFACE...A VERY STRONG COLD FRONT WILL PUSH THROUGH EARLY
SATURDAY AND THE STRONG UPPER FORCING ALOFT WILL PROMOTE
CYCLOGENESIS OFF THE OUTER BANKS. THE FIRST FORECAST ISSUE REVOLVES
AROUND THE PRECIPITATION POTENTIAL ON SATURDAY. VERY IMPRESSIVE DEEP
LAYER FORCING WITH THIS SYSTEM WILL SPREAD ACROSS THE AREA INCLUDING
STRONG PVA...UPPER LEVEL JET DYNAMICS...EVEN A SLOT OF LOW LEVEL
FRONTOGENESIS LATER ON SATURDAY. FURTHERMORE...THE ARRIVAL OF THE
IMPRESSIVE COLD POOL ALOFT...500 MB TEMPS AROUND -26C...WILL HELP
STEEPEN MID LEVEL LAPSE RATES THROUGH THE DAY. POPS HAVE BEEN
INCREASED INTO THE CATEGORICAL RANGE THROUGH THE DAY AS A RESULT.
ONE THING TO WATCH FOR IS THE STEEPENING MID LEVEL LAPSE RATES AND
FALLING FREEZING LEVELS WILL LIKELY ALLOW FOR SOME PRECIPITATION TO
FALL AS GRAUPEL AT TIMES ESPECIALLY LATER ON SATURDAY. THE TOP OF
THE MOIST LAYER WILL DEFINITELY REACH INTO THE DENDRITIC CRYSTAL
GROWTH ZONE...THEN UNDERGO AT LEAST PARTIAL MELTING AS IT FALLS
THROUGH THE ABOVE FREEZING NEAR SURFACE LAYER. GRAUPEL WILL CERTAINLY
NOT BE THE PREDOMINANT PRECIPITATION TYPE AND THE WEATHER GRIDS ONLY
MENTION LIQUID RAIN...BUT IT IS WORTH MENTIONING NONETHELESS.
PRECIPITATION WILL COME TO AN END STARTING SATURDAY EVENING AS THE
FORCING BEGINS TO EXIT THE REGION. THE NEXT FORECAST ISSUE IS THE
ARRIVAL OF WELL BELOW NORMAL TEMPERATURES AND THE POTENTIAL FOR AN
ADVECTIVE FREEZE INLAND SATURDAY NIGHT. 850 MB TEMPS ARE VERY
COLD...RUNNING ABOUT 5 STANDARD DEVIATIONS BELOW NORMAL...AND THE
LINGERING GRADIENT WILL KEEP WINDS STRONG ENOUGH TO PRECLUDE MUCH IN
THE WAY OF FROST CONCERNS. SUNDAY HIGHS WILL BE QUITE COOL WITH MID
50S IN MOST AREAS...AND WILL THREATEN RECORD LOW MAXIMUM TEMPERATURE
RECORDS AT THE CLIMATE SITES. SUCH HIGH TEMPERATURES ARE ALMOST 20
DEGREES BELOW FOR EARLY NOVEMBER.

&&

.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
SUNDAY NIGHT WILL BE THE COLDEST NIGHT OF THE PERIOD AS THE PRESSURE
GRADIENT WEAKENS SUFFICIENTLY TO ALLOW FOR GOOD RADIATIONAL COOLING
CONDITIONS. THERE APPEARS TO BE A LINGERING FEW MPH OF NE WINDS THAT
MAY SPARE INLAND ZONES FREEZING TEMPS WHEREAS WEAK OCEAN INFLUENCE
SHOULD FAVOR UPPER 30S COAST. THE CENTER OF THE HIGH IS HESITANT TO
GET EAST OF THE REGION ON TUESDAY PRECLUDING BONA FIDE RETURN FLOW
AND SO THE CLIMO TEMPS SEEN IN MOS BULLETINS SEEM TOO
OPTIMISTIC...AND HAVE BEEN UNDERCUT BY JUST A FEW DEGREES. THE
ACTUAL RETURN FLOW SHOULD GET UNDERWAY TUESDAY NIGHT INTO WEDNESDAY.
WILL ADD SOME LOW POPS IN THE RETURN FLOW BUT MOST OF THE MOISTENING
MAY STILL BE DEDICATED TO PW RECOVERY FROM THE COLD AIRMASS AS
OPPOSED TO ACTUAL RAINFALL.

&&

.AVIATION /20Z THURSDAY THROUGH TUESDAY/...
TEMPO MVFR CIGS ARE POSSIBLE FOR THE NEXT HOUR OR TWO...MAINLY AT
MYR AND CRE. OTHERWISE...HIGH PRESSURE WILL BUILD OVER THE AREA
WITH GENERALLY VFR CONDITIONS THROUGH 18Z FRI. WE COULD SEE AN
INCREASE IN CLOUD COVER AT ALL TERMINALS TONIGHT...BUT CONFIDENCE
REMAINS TOO LOW TO MENTION FLIGHT RESTRICTIONS AT ANY TERMINAL.

EXTENDED OUTLOOK...MVFR OR LOWER CEILINGS WILL BE POSSIBLE BEGINNING
EARLY SATURDAY MORNING AND THEN LINGERING THROUGH MUCH OF THE
DAY. VFR CONDITIONS WILL THEN BECOME PREVAILING SATURDAY NIGHT
INTO SUNDAY. NORTHWEST WINDS WILL INCREASE AND BECOME QUITE GUSTY
STARTING SATURDAY MORNING AND CONTINUING INTO SATURDAY NIGHT.

&&

.MARINE...
NEAR TERM /THROUGH TONIGHT/...
CONDITIONS ARE EXPECTED TO REMAIN BELOW SMALL CRAFT ADVISORY LEVELS
WHILE HIGH PRESSURE BUILDS OVER THE WATERS THIS EVENING AND TONIGHT
BEHIND A STALLING COLD FRONT OFF THE MID ATLANTIC AND SOUTHEAST
UNITED STATES. HOWEVER...WINDS/SEAS SHOULD REMAIN ELEVATED AS AN
AREA OF LOW PRESSURE DEVELOPS ALONG THE STALLED FRONT OFFSHORE AND
RESULTS IN A TIGHTENED PRESSURE GRADIENT OVER THE WATERS LATE. IN
GENERAL...NORTH/NORTHEAST WINDS WILL INCREASE TO 15-20 KTS...WITH
POSSIBLY A FEW 25 KT GUSTS LATE BEYOND 10 NM FROM THE COAST. SEAS
WILL GENERALLY RANGE BETWEEN 2-3 FT INITIALLY...BEFORE BUILDING UP
TO 3-4 FT LATE...HIGHEST BEYOND 10 NM FROM THE COAST.

SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
FRIDAY THROUGH TUESDAY...THE BULK OF THE SIGNIFICANT MARINE
CONDITIONS WILL OCCUR STARTING EARLY SATURDAY AS A VERY STRONG COLD
FRONT BEGINS TO IMPACT THE LOCAL WATERS. UP UNTIL THAT POINT...NORTH
WINDS MAY SURGE INTO THE 15-20 KT RANGE WITH SEAS UP TO 4-5 FT OUT
NEAR 20 NM AT TIMES.

BEGINNING SATURDAY MORNING...THE COLD FRONT WILL BEGIN TO SWEEP
ACROSS THE WATERS WITH A SIGNIFICANT INCREASE IN WINDS/SEAS THROUGH
THE DAY. THE AIRMASS BEHIND THE FRONT IS QUITE COLD AND WITH WATER
TEMPERATURES STILL IN THE LOW 70S...IDEAL MIXING CONDITIONS WILL BE
IN PLACE ESPECIALLY SATURDAY NIGHT AS THE COLD ADVECTION REACHES IT
PEAK. THE DEEPENING MIXING OVER THE WATERS WILL BE HAPPENING
COINCIDENT WITH A DEEPENING AREA OF LOW PRESSURE PULLING AWAY TO THE
NORTHEAST OFF THE OUTER BANKS. MODEL GUIDANCE SHOWS 1000 MB
GEOSTROPHIC WINDS INCREASING TO 70 KT ACROSS MUCH OF THE WATERS
SATURDAY EVENING AND EARLY SATURDAY NIGHT. WITH THE EXPECTED MIXING
THIS WILL EASILY SUPPORT GALE CONDITIONS ACROSS ALL OF THE WATERS.
IN FACT...GIVEN THE MOST RECENT MODEL SOUNDINGS IT IS NOT OUT OF THE
QUESTION TO SEE A VERY BRIEF PERIOD OF STORM FORCE GUSTS WITH THE
INITIAL PUNCH OF WIND BEHIND THE FRONT IN THE 00-03Z SUNDAY TIME
PERIOD. AS SUCH...A GALE WATCH HAS BEEN HOISTED STARTING AT 13Z
SATURDAY FOR THE SOUTH CAROLINA WATERS AND 17Z FOR THE NORTH
CAROLINA WATERS. GALES WILL CONTINUE THROUGH SATURDAY NIGHT AND THEN
BEGIN TO DIMINISH TO JUST SMALL CRAFT ADVISORY WINDS BY SUNDAY
MORNING.

LONG TERM /SUNDAY THROUGH MONDAY/...
THE GRADIENT WILL STILL BE QUITE STRONG SUNDAY MORNING ESPECIALLY
OVER NORTHERN ZONES. HOWEVER THERE WILL BE A MARKED ABATING TREND AS
THE DAY WEARS ON DUE TO THE RAPID NORTHEASTERLY MOVEMENT OF THE
STILL DEEPENING LOW THAT AFFECTED US DIRECTLY SATURDAY AND SATURDAY
NIGHT. IN FACT AS IT APPEARS NOW THERE MAY BE NO HEADLINES NEEDED BY
MIDDAY OR SO. FOR MUCH OF MONDAY HIGH PRESSURE WILL ELONGATE UP AND
DOWN THE CAROLINAS WITH A LATE DAY SHIFT TOWARDS THE COASTLINE. N
WINDS WILL VEER TO THE NE AND GROW LIGHTER. HIGH PRESSURE WILL BUILD
IN EARLY NEXT WEEK AND MUCH QUIETER CONDITIONS ARE EXPECTED.

&&

.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...GALE WATCH FROM SATURDAY MORNING THROUGH LATE SATURDAY NIGHT
     FOR AMZ254-256.

     GALE WATCH FROM SATURDAY AFTERNOON THROUGH SUNDAY MORNING FOR
     AMZ250-252.

&&

$$
SYNOPSIS...99
NEAR TERM...99
SHORT TERM...99
LONG TERM...99
AVIATION...99
MARINE...99






USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.