Area Forecast Discussion
Issued by NWS Wilmington, NC

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000
FXUS62 KILM 230539
AFDILM

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WILMINGTON NC
139 AM EDT WED JUL 23 2014

.SYNOPSIS...
BERMUDA HIGH PRESSURE WILL BUILD INTO THE AREA INTO THURSDAY. A COLD
FRONT WILL APPROACH FROM THE NORTHWEST LATE THURSDAY...STALLING NEAR
THE COAST FOR THE WEEKEND. ANOTHER COLD FRONT WILL APPROACH FROM THE
NORTHWEST MONDAY OR TUESDAY.

&&

.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
AS OF 1015 PM TUESDAY...LATEST KLTX 88D CONTINUES TO INDICATE A
DIMINISHING TREND TO THE SHOWER AND THUNDERSTORM ACTIVITY ACROSS
THE ILM CWA. WITH THE DAYS HEATING OVERWITH...CONVECTION WILL
BECOME MORE DIFFICULT TO SUSTAIN. A SLOW MOVING MID-LEVEL S/W TROF
OR IMPULSE OFFSHORE FROM THE CAROLINA COASTS...IS PROGGED TO PUSH
OFF TO THE NORTHEAST OVERNIGHT INTO WEDNESDAY...AWAY FROM THE ILM
CWA. ENOUGH FORCING/DYNAMICS FROM THIS UPPER S/W TROF WILL PRODUCE
CONVECTION OVER THE ADJACENT ATL WATERS THAT MAY DRIFT ONSHORE...
MAINLY FROM LITTLE RIVER INLET NORTH TO SURF CITY...DURING THE
PRE-DAWN WEDNESDAY HOURS. LATEST SREF MODEL HIGHLIGHTS THIS
DIMINISHING TREND TO POPS OVER LAND BUT DOES KEEP PCPN OCCURRING
OVER THE ADJACENT ATL WATERS. LOW TO MID 70S FOR TONIGHTS LOWS MAY
NEED TO BE BUMPED UP HIER BY A CATEGORY...ESPECIALLY ACROSS THE
COASTAL COUNTIES ESPECIALLY WITH LATEST SFC DEWPOINTS HOLDING IN THE
MID 70S. CLOUDINESS MORE WIDESPREAD AND OPAQUE IN NATURE AT THE
MOMENT...WILL SLOWLY THIN OVERNIGHT AND IN TURN COULD LEAD TO
SOME PARTIAL CLEAR SKIES. THIS MAY LEAD TO PATCHY/AREAS OF
RADIATIONAL FOG DEVELOPMENT OVERNIGHT.

&&

.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH THURSDAY NIGHT/...
AS OF 330 PM TUESDAY...UPPER LOW OVER THE GULF COAST WILL CONTINUE
RETROGRADING ON WEDNESDAY...ALLOWING A 500 MB RIDGE TO BRIEFLY
BUILD INTO THE SOUTHEAST. MID LEVEL FLOW WILL BECOME MORE WESTERLY
DURING THE AFTERNOON/EVENING HOURS...FINALLY BRINGING AN END TO
THE CONTINUOUS CHANNEL OF DEEP MOISTURE THAT HAS FUNNELED INTO THE
AREA OVER THE PAST COUPLE DAYS. MOST ONGOING SHOWER ACTIVITY
WEDNESDAY MORNING WILL BE OFFSHORE...BUT WILL MENTION HIGHER POPS
ALONG THE COAST EARLY. PWAT VALUES WILL REMAIN IN THE 2.0 INCH
RANGE DURING THE DAY...SO STILL EXPECT ISOLATED TO SCATTERED
CONVECTION IN THE AFTN ALONG THE SEA BREEZE. BUT OVERALL PCPN
COVERAGE SHOULD BE LESS WIDESPREAD THAN WE HAVE SEEN OVER THE PAST
COUPLE DAYS. 500 MB HEIGHTS WILL GRADUALLY FALL ON THURSDAY AHEAD
OF AN APPROACHING COLD FRONT. RAIN CHANCES INCREASE AGAIN LATE
THURSDAY INTO EARLY FRIDAY AS THE FRONT NEARS OUR FORECAST AREA.
BY 12Z FRIDAY THE BOUNDARY WILL BE DRAPED ACROSS THE
CAROLINAS...PERHAPS EVEN BISECTING OUR FORECAST AREA AS IT STALLS.

THE SFC PRESSURE GRADIENT WILL TIGHTEN BETWEEN BERMUDA HIGH PRESSURE
AND A PRE-FRONTAL TROUGH...WITH STRENGTHENING S-SW WINDS THROUGH THE
PERIOD. 1000-500 MB THICKNESSES INDICATE A WARMING TREND AS THE FLOW
ACQUIRES A MORE WESTERLY COMPONENT. EXPECT HIGHS TO CLIMB INTO THE
LOW 90S WEDNESDAY AND MID 90S THURSDAY ACROSS OUR INLAND ZONES...
WITH HEAT INDICES NEARING OR EXCEEDING TRIPLE DIGITS. LOW TEMPS BOTH
NIGHTS WILL BE IN THE MID 70S.

&&

.LONG TERM /FRIDAY THROUGH MONDAY/...
AS OF 330 AM TUESDAY...COLD FRONT MAY BE HUNG UP RIGHT ALONG THE
COAST FRI MORNING BUT NAM WANTS TO PUSH IT SOUTH AND EAST OF AREA
LEAVING HIGH PRESSURE IN CONTROL. NOT CONFIDENT THAT THE BOUNDARY
WILL GET TOO FAR SOUTH AS H5 TROUGH LIFTS NORTH LEAVING A VERY BROAD
MID TO UPPER TROUGH ANCHORED OVER THE GREAT LAKES MAINTAINING MORE
OF A SW FLOW ALOFT AND NOT GIVING MUCH OF PUSH TO THE COLD FRONT.
THEREFORE WILL KEEP FRONT JUST TO OUR NORTHWEST ON FRI. DEEP SW FLOW
WILL KEEP A WARMER AND MORE HUMID AIR MASS OVER THE AREA LEAVING
POTENTIAL FOR LOCALIZED CONVECTION THROUGH THE WEEKEND.

MID TO UPPER TROUGH WILL DIG DOWN FROM THE GREAT LAKES COME MONDAY
PUSHING ANOTHER COLD FRONT INTO THE CAROLINAS. THIS WILL PRODUCE
MORE WIDESPREAD CONVECTION IN INCREASED UPPER LEVEL SUPPORT LATER
ON MONDAY. ONCE AGAIN UPPER LEVEL TROUGH WILL REMAIN TO OUR WEST
LEAVING A FLOW RUNNING MORE PARALLEL TO FRONT AND NOT GIVING IT
TOO STRONG OF A PUSH THROUGH THE AREA. THEREFORE MAY NOT SEE TOO
MUCH OF AN AIR MASS CHANGE BEHIND FRONT.

OVERALL EXPECT GREATEST POTENTIAL FOR MORE WIDESPREAD CONVECTION
EARLY FRI AND AGAIN MON AFTN INTO EARLY TUES...BUT EXPECT MORE
TYPICAL DIURNAL TYPE SHWR ACTIVITY MOST DAYS. SOME DRIER AIR SHOULD
MAKE IT INTO INLAND AREAS ON FRI AND ON TUES BEHIND FRONTS...BUT
WILL MOST LIKELY REMAIN JUST TO THE WEST OF FORECAST AREA. TEMPS WILL
BASICALLY BE ABOVE CLIMO WITH OVERNIGHT LOWS IN THE 70S AND DAY
TIME HIGHS INTO THE 90S MOST DAYS WITH LOWER TEMPS EXPECTED. AS
TROUGH DIGS DOWN THURS INTO FRI AND AGAIN MON INTO TUES MAY SEE
BELOW NORMAL TEMPS IN LOWERED H5 HEIGHTS.

&&

.AVIATION /06Z WEDNESDAY THROUGH SUNDAY/...
AS OF 06Z...SOME NOCTURNAL SHOWERS ARE POSSIBLE NEAR THE COAST NEAR
10Z. STILL A BIT OF CONVECTIVE DEBRIS...HOWEVER MOST OF THAT WILL BE
DISSIPATING...ALLOWING MODERATE RADIATIONAL COOLING TO COMMENCE. FOG
WILL RETURN TO THE REGION...HOWEVER LOW LEVEL MOISTURE IS NOT AS
PREVALENT AS LAST NIGHT SO WILL BACK OFF A BIT ON THE INTENSITY AT
THIS TIME...INCLUDING IFR VISIBILITIES AND CEILINGS AT KLBT AND KFLO.

SOMEWHAT DRIER AIR WILL BE IN PLACE TODAY AS BERMUDA RIDGE WILL BE
IN CLOSER PROXIMITY. THUS...EXPECT MUCH LESS CONVECTION TO DEVELOP.
WILL INCLUDE TEMPO MVFR CONDITIONS IN A THUNDERSTORM AT KILM/KCRE
AND KMYR 16Z-21Z.

EXTENDED OUTLOOK...CHANCE OF SHOWERS/TSTMS WILL PERSIST THROUGH THE
EXTENDED PERIOD. EXPECT PREDOMINANTLY VFR CONDITIONS WITH TEMPO
PERIODS OF MVFR/IFR CIGS/VSBYS IN STORMS.

&&

.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 1020 PM TUESDAY...LATEST SFC PRESSURE PATTERN REMAINS
CONDUCIVE TO A SE-S WIND DIRECTION. THE SFC PG TO REMAIN RELAXED
THIS EVENING...BUT TOWARDS DAYBREAK WEDNESDAY...THE SFC PG IS
PROGGED TO TIGHTEN AS THE ILM WATERS BECOMES NESTLED BETWEEN
STRONG BERMUDA HIGH PRESSURE CENTERED WELL OFF THE SE U.S.
COAST...AND A STRENGTHENING PIEDMONT TROF ACROSS THE CENTRAL
CAROLINAS. OVERALL...WINDS PROGGED TO VEER TO THE SSE THRU SW
DIRECTIONS. SPEEDS TO INCREASE TO 10-15 KT.

SIGNIFICANT SEAS WILL BE A PRODUCT OF A SOMEWHAT DECAYED 2 FOOT
ESE-SE GROUND SWELL EXHIBITING 8 TO 9 SECOND PERIODS. AND A
BUILDING 2 TO 3 FOOT WIND DRIVEN WAVES AT 5 TO 6 SECOND PERIODS.

SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
AS OF 330 PM TUESDAY...SOUTHWEST WINDS AROUND 15 KTS WILL PREVAIL
WEDNESDAY AFTN THROUGH THURSDAY AS THE GRADIENT IS PINCHED BETWEEN
BERMUDA HIGH PRESSURE AND A PRE-FRONTAL TROUGH. SEAS WILL BE 3-4
FT...BUILDING TO 4-5 FT ON THURSDAY ACROSS AMZ250/252 WHERE WINDS
MAY GUST TO 20 KTS. THE DOMINANT WAVE GROUP WILL BE A 5-6 SECOND
SOUTHERLY WIND CHOP. WINDS AND SEAS WILL RELAX A BIT TOWARD THE
END OF THE PERIOD AS A COLD FRONT DROPPING SOUTHWARD NEARS THE
COAST.

LONG TERM /FRIDAY THROUGH SATURDAY/...
AS OF 330 AM TUESDAY...COLD FRONT REACHES INTO THE CAROLINAS EARLY
FRI BUT WILL MOST LIKELY STALL AND DISSIPATE OVER INLAND CAROLINAS
OVER THE WEEKEND. EXPECT TO MAINTAIN A SW FLOW AROUND BERMUDA HIGH
WEAKENING AS GRADIENT RELAXES THROUGH FRIDAY INTO SATURDAY AS
FRONT DISSIPATES OVER THE CAROLINAS. SEAS UP TO 3 TO 5 FT EARLY
FRI WILL FALL BACK DOWN TO 2 TO 4 FT THROUGH LATE FRI INTO
SATURDAY.

&&

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

&&

$$

NEAR TERM...DCH
SHORT TERM...BJR
LONG TERM...MBB
AVIATION...RJD/DL








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