Area Forecast Discussion
Issued by NWS Wilmington, NC

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000
FXUS62 KILM 260217
AFDILM

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WILMINGTON NC
1017 PM EDT FRI JUL 25 2014

.SYNOPSIS...
A STALLED FRONT ACROSS NORTHEAST SOUTH CAROLINA WILL LIFT NORTH
AND DISSIPATE OVERNIGHT INTO SATURDAY. BUILDING HIGH PRESSURE WILL
FOLLOW...BRINGING HOT AND HUMID CONDITIONS OVER THE WEEKEND AND
MONDAY. ANOTHER UNUSUALLY STRONG COLD FRONT MAY BRING STRONG
THUNDERSTORMS LATE MONDAY...FOLLOWED BY COOLER AND DRIER WEATHER
TUESDAY...POSSIBLY THROUGH MUCH OF NEXT WEEK.

&&

.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
AS OF 10:30 PM FRIDAY...A FEW SHOWERS HAVE DRIFTED INTO
WILLIAMSBURG COUNTY...OTHERWISE ALL IS QUIET. NO CHANGES NEEDED TO
THE FORECAST AS CURRENT SLIGHT CHANCE FOR OUR SOUTHERN COUNTIES
WILL COVER SPOTTY SHOWER ACTIVITY FOR THIS EVENING.

RELEVANT PORTION OF PREVIOUS DISCUSSION FOLLOWS:

MODELS STRUGGLED INITIALLY WITH THE EXCEPTIONAL SOUTHWARD MOVEMENT
OF THE COLD FRONT EARLIER THIS MORNING...AND ARE NOW STRUGGLING WITH
THE FRONT`S SLUGGISH RETURN NORTHWARD. THE 12Z NAM HAD VERY POOR
INITIALIZATION WITH THIS BOUNDARY. THE 12Z GFS WAS INITIALIZED A
LITTLE BETTER BUT I AM ESSENTIALLY USING THE RUC...HRRR...AND 12Z
WRF-ARW AND WRF-NM MODELS FOR WIND DIRECTION FORECASTS TONIGHT. AS
SYNOPTIC HIGH PRESSURE MOVES EAST OFF THE MID-ATLANTIC COAST THIS
SHOULD INDUCE THE FRONT TO RETURN NORTHWARD...ALBEIT MORE SLOWLY
THAN MOST SYNOPTIC GUIDANCE IS INDICATING.

WITH RICH LOW-LEVEL MOISTURE AND RELATIVELY DRY AIR IN THE
MID-LEVELS...CALM WINDS...AND SLOWLY CLEARING SKIES...IT IS A GOOD
SETUP FOR FOG OR LOW STRATUS OVERNIGHT. VISIBILITIES WILL PROBABLY
BEGIN DECREASING AFTER MIDNIGHT WITH THE WORST CONDITIONS AROUND
DAYBREAK. LOWS SHOULD REACH THE LOWER 70S WITH SOME MID 70S NEAR THE
COAST.

&&

.SHORT TERM /6 AM SATURDAY MORNING THROUGH SUNDAY NIGHT/...
AS OF 315 PM FRIDAY...MAIN WEEKEND WEATHER HEADLINE IS EXPANDING
HEAT AND HUMIDITY. HEAT INDICES/APPARENT TEMPERATURES FACTORING
IN ELEVATED DEWPOINT VALUES...YIELDS 97-102 DEGREE INDICES FOR
SATURDAY...AND INTO THE BROILER SUNDAY AS MAXIMUM APPARENT TEMPS
SUNDAY AFTERNOON CREST TO 104-107 DEGREES. IF CONSISTENCY HOLDS
IN THE MAX TEMP FORECAST...THEN WE WILL BE LOOKING AT PROSPECTS
OF A HEAT ADVISORY NEEDED ON SUNDAY.

PCPN-WISE...BEST CHANCE LOOKS TO BE SATURDAY AS A DECAYING FRONTAL
BOUNDARY LIFTS NORTH ACROSS CAPE FEAR AND SE NC. DRY MID-LEVEL AIR
WILL PLACE LIMITATIONS OF PCPN EXTENT AND MAGNITUDE SATURDAY...BUT
A FEW SHOWERS SHOULD BE EXPECTED ON SATURDAY AS LOW-LEVEL MOISTURE
LINGERS. SUNDAY LOOKS DRYISH WITH WESTERLY FLOW THROUGH MUCH OF
THE COLUMN SQUELCHING RAIN CHANCES. BECAUSE OF INTENSE HEAT AT
THE SURFACE SUNDAY HOWEVER...AN ISOLATED TSTM CANNOT BE RULED
ENTIRELY.

DUE TO THE GRADUAL BUILD UP OF HEAT...VERY MILD MINIMUMS SUNDAY
AND MONDAY DAYBREAK ARE ANTICIPATED...ESSENTIALLY MIDDLE 70S TO
THE LOWER 80S AND MILDEST NEAR THE SEA...PARTICULARLY AS WE SEE
STILL SW WINDS HOLDING UP IN THE OVERNIGHT PERIODS...ESPECIALLY
LATE SUNDAY INTO EARLY MONDAY.

&&

.LONG TERM /MONDAY THROUGH FRIDAY/...
AS OF 315 PM FRIDAY...IMPRESSIVE MID-LEVEL AMPLIFICATION THROUGH THE
EXTENDED WILL DRIVE ACTIVE WEATHER THE FIRST PORTION OF THE
EXTENDED...BUT QUIET AND COOL CONDITIONS WILL FOLLOW THE MAJORITY
OF THE UPCOMING WEEK.

MONDAY SHAPING UP TO BE ONE OF THE HOTTEST DAYS OF THE YEAR
LOCALLY...AS RETURN FLOW STRENGTH INCREASES...AND 850MB TEMPS CLIMB
ABOVE 20C. COMBINE THIS WITH WHAT WILL LIKELY BE A VERY WARM START
TO THE DAY (WARM OVERNIGHT LOWS FROM SUNDAY)...AND MONDAY WILL
FEATURE WIDESPREAD MID 90S ACROSS THE AREA...WITH UPPER 90S POSSIBLE
IN MANY SPOTS. THESE TEMPS COMBINED WITH HIGH DEWPOINTS WILL BRING
APPARENT TEMPS TO NEAR HEAT ADVISORY CRITERIA ON MONDAY. THIS WILL
BE THE LAST SUMMER-LIKE DAY FOR QUITE SOME TIME THOUGH...AS AN
ANOMALOUSLY SHARP TROUGH (UP TO -4 SD) DIVES INTO THE EASTERN CONUS.
BENEATH THIS TROUGH A STRONG COLD FRONT WILL CROSS THE LOCAL AREA
MONDAY EVE AND NIGHT...MOVING OFFSHORE BY TUESDAY MORNING. A STRONG
COLD FRONT DIVING INTO A VERY WARM UNSTABLE AIRMASS WILL SUPPORT THE
CHANCE FOR STRONG CONVECTION ON MONDAY...AND SPC IS ALREADY
HIGHLIGHTING THE REGION IN THE D4 OUTLOOK. IT IS TOO EARLY TO FOCUS
ON DETAILS OF COURSE...BUT A STRONG COLD FRONT IMPINGING ON A HIGHLY
UNSTABLE AIRMASS WITH RAPID HEIGHT FALLS AND STRONG MID-LEVEL FLOW
IS UNQUESTIONABLY A SOLUTION WHICH SUPPORTS CONVECTION. WILL BUMP TO
LIKELY POP MONDAY FOR MUCH OF THE AREA.

TO USE THE WORD SIGNIFICANT TO DESCRIBE THE AIR MASS CHANGE FROM
MONDAY THROUGH WEDNESDAY MAY BE AN UNDERSTATEMENT...AS 850MB TEMPS
DROP FROM AROUND 21C (+2 SD) TO 13C (-2 SD) IN JUST 48 HOURS! WHILE
THIS OCCURS...PWATS DROP BELOW 1 INCH BY WEDNESDAY AS WELL...AND
THUS THE TUE/WED/THU TIMEFRAME SHOULD BE DRY LOCALLY...ALBEIT WITH
TEMPS WELL BELOW NORMAL FOR LATE JULY. ALTHOUGH STRONG CAA EVENTS IN
JULY ARE...NOT SURPRISINGLY...RARE...EXPECT GUIDANCE IS OVERDOING
TEMP FORECASTS MID WEEK AND WILL UNDERCUT NUMBERS...WITH TEMPS
LIKELY 5-10 DEGREES BELOW NORMAL MUCH OF NEXT WEEK. LATE IN THE
WEEK...MID-LEVEL TROUGH BEGINS TO WEAKEN...AND STRONG RIDGE OVER THE
ATLANTIC BEGINS TO PUSH BACK TO THE WEST DRIVING A RETROGRADING
PATTERN INTO FRIDAY...DRIVING WARMING TEMPS BUT INCREASING CHANCES
FOR POP.

&&

.AVIATION /02Z SATURDAY THROUGH WEDNESDAY/...
AS OF 00Z...STILL SOME POCKETS OF MVFR CEILINGS...BUT SHOULD BE
PREDOMINATELY VFR THIS EVENING. RESIDUAL LOW LEVEL MOISTURE WILL
PROBABLY DEVELOP SOME LIGHT FOG STARTING AROUND 08Z. SATURDAY...A
WEAK PIEDMONT TROUGH WILL RESIDE OVER THE REGION. SOME CONVECTION
WILL DEVELOP FIRST ALONG THE SEA BREEZE BOUNDARY...WITH ISOLATED
CONVECTION INLAND WHERE THE BEST CAPE WILL DEVELOP. SOUTHWESTERLY
FLOW IS EXPECTED THROUGH THE FORECAST PERIOD...A BIT MORE SOUTHERLY
ALONG THE COAST AND PERHAPS A BIT STRONGER.

EXTENDED OUTLOOK...SHOWERS/TSTMS/TEMPO MVFR POSSIBLE SUNDAY AND
MONDAY. OTHERWISE EXPECT VFR.

&&

.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 10:30 PM FRIDAY...NO CHANGES TO THE FORECAST WITH THE LATEST
UPDATE. PREVIOUS DISCUSSION FOLLOWS:

ISOLATED SHOWERS POSSIBLE AFTER MIDNIGHT OVER THE OUTER FRINGES OF
THE WATERS...BUT ANY MORE SUBSTANTIAL THUNDERSTORM ACTIVITY IS
UNLIKELY. A COLD FRONT SHOULD BEGIN TO MOVE NORTHWARD
OVERNIGHT...REACHING CAPE FEAR LATER THIS EVENING AND EVENTUALLY
MOVING NORTHWARD INTO EASTERN NORTH CAROLINA. WINDS WILL TURN
SOUTHERLY OVERNIGHT...BUT WITH LITTLE INCREASE IN WIND SPEED
EXPECTED FROM PRESENT 10 KT RANGE.

SEAS CURRENTLY 2-3 FEET ARE EVENLY SPLIT BETWEEN A 9-SECOND
SOUTHEAST SWELL AND SHORTER PERIOD WAVES PRODUCED BY LOCAL WINDS.
LITTLE CHANGE IS ANTICIPATED OVERNIGHT.

SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
AS OF 315 PM FRIDAY...THE MARINE WEEKEND HEADLINE...INCREASING SW
WINDS SATURDAY THROUGH SUNDAY...WITH AN EXERCISE CAUTION MARINE
CONDITIONS LIKELY DEVELOPING SUNDAY OR SUNDAY NIGHT...FOR 15-20 KT
SW WINDS AND SEAS OF 4-5 FEET. THEREFOR WHILE SATURDAY WILL BE A
MANAGEABLE DAY FOR BOATING...SUNDAY WILL BECOME BUMPY AND A BIT
MORE HAZARDOUS AS WIND-WAVES CONTINUE TO GROW IN PERSISTENT AND
MODERATELY STRONG SW WINDS. ISOLATED TSTMS EXPECTED ON THE WATERS
EARLY SATURDAY...AND POTENTIALLY LATE SUNDAY NIGHT OFFSHORE.

.LONG TERM /MONDAY THROUGH WEDNESDAY/...
AS OF 3 PM THURSDAY...STRONG PRE-FRONTAL FLOW AHEAD OF A COLD
FRONT WILL PUSH WINDS UP ABOVE 20 KTS FROM THE SW ON
MONDAY...DRIVING SEAS TO 4-6 FT...AND A SMALL CRAFT ADVISORY WILL
LIKELY BE NEEDED ON MONDAY. THIS FRONT WILL CROSS THE WATERS
MONDAY NIGHT...WITH A RAPID WIND SHIFT TO THE NW BY TUESDAY
MORNING...AND SPEEDS EASING THROUGH TUESDAY TO 5-10 KTS. WEAK AREA
OF HIGH PRESSURE WILL BUILD ACROSS THE WATERS THEREAFTER...CAUSING
WINDS TO BECOME NE AROUND 10 KTS. AFTER THE SCA CONDITIONS SUBSIDE
MONDAY NIGHT...SEAS WILL BE 2-4 FT THROUGH THE REMAINDER OF THE
PERIOD.

&&

.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.

&&

$$

SYNOPSIS...MJC
NEAR TERM...REK/TRA
SHORT TERM...MJC
LONG TERM...JDW
AVIATION...DL
MARINE...MJC/REK/TRA/JDW



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