Area Forecast Discussion
Issued by NWS Wilmington, NC

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000
FXUS62 KILM 030520
AFDILM

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WILMINGTON NC
120 AM EDT TUE MAY 3 2016

.SYNOPSIS...
SHOWERS AND THUNDERSTORMS ARE EXPECTED THROUGH EARLY WEDNESDAY
AHEAD OF AN APPROACHING COLD FRONT. A COLD UPPER LOW WILL DIP
ACROSS THE CAROLINAS LATE IN THE WEEK...BRINGING CHILLIER
TEMPERATURES AND SCATTERED GUSTY SHOWERS THURSDAY AND FRIDAY.
DRYING AND WARMING WILL FOLLOW INTO THE UPCOMING WEEKEND.

&&

.NEAR TERM /UNTIL 6 AM THIS MORNING/...
AS OF 120 AM TUESDAY...NO CHANGES WITH THE EARLY MORNING UPDATES.

SHOWERS WERE STILL OCCURRING ACROSS THE FORECAST AREA THIS EVE.
THERE WERE STILL A COUPLE LIGHTNING STRIKES ACROSS EXTREME
NORTHERN BLADEN COUNTY. WE EXPECT THE ONGOING ACTIVITY TO CONTINUE
TO WEAKEN LATE THIS EVE.

HOWEVER...THERE IS STILL SIGNIFICANT CONVECTION ALONG AND AHEAD OF
A COLD FRONT ACROSS WESTERN NORTH CAROLINA SOUTHWARD THROUGH THE
WESTERN HALF OF SOUTH CAROLINA AND THEN INTO GEORGIA. WE EXPECT
THIS CONVECTION WILL NOT DISSIPATE EVEN WITH THE LOSS OF HEATING
AS A GULF OF MEXICO TAP COMBINES WITH FRONTAL LIFT AND A DIGGING
UPPER TROUGH.

DEEP AND MOIST SOUTHWEST FLOW WILL PERSIST AHEAD OF A STRONG
UPSTREAM TROUGH. A MID-LEVEL SHORTWAVE TROUGH WILL APPROACH FROM
THE SW AND W. THUS...HIGH POPS WILL REMAIN IN THE FORECAST
OVERNIGHT INTO TUE MORNING. THE ARW AND HRRR HIGH RESOLUTION
MODELS SHOW SHOWERS AND THUNDERSTORMS HOLDING TOGETHER AS THEY
ROLL ACROSS THE FORECAST AREA...ROUGHLY BETWEEN 07-08Z AND 13-14Z.
THE MAIN RISK WILL BE HEAVY DOWNPOURS WHICH MAY RESULT IN BRIEF
PONDING OF WATER IN LOW LYING AND POOR DRAINAGE AREAS.

&&

.SHORT TERM /6 AM THIS MORNING THROUGH WEDNESDAY NIGHT/...
AS OF 245 PM MONDAY...VERY GOOD CHANCES FOR RAIN CONTINUE INTO
THE SHORT TERM AS A COLD FRONT SLOWLY DROPS SE ACROSS THE EASTERN
CAROLINAS AND AN UPPER TROUGH CONTINUES TO DEEPEN OVER EASTERN
CONUS. ATMOSPHERE WILL REMAIN MOIST AND MARGINALLY TO MODERATELY
UNSTABLE THROUGH AT LEAST TUESDAY. THE BEST CHANCES FOR STRONG TO
SEVERE CONVECTION WILL BE TUESDAY AFTERNOON AND EVENING AS A
SERIES OF FACTORS COME IN TO PLAY...INCLUDING FAVORABLE SHEAR
PROFILES...DEEP MOISTURE AND LIFT ASSOCIATED WITH THE ADVANCING
COLD FRONT...IN ADDITION TO THE AFOREMENTIONED INSTABILITY AND
AVAILABLE MOISTURE. THE COLD FRONT SHOULD BE POSITIONED MORE OR
LESS ALONG THE COAST BY DAYBREAK ON WEDNESDAY AND WILL EITHER
STALL OR SLOWLY PUSH OFFSHORE THEREAFTER. BOTH GFS AND NAM
GUIDANCE SUGGEST A VIGOROUS SHORT WAVE DROPPING SE ACROSS THE
EASTERN CAROLINAS MIDDAY ON WEDNESDAY...AND THIS COULD BECOME THE
FOCUS FOR ADDITIONAL CONVECTION THEN. HOWEVER...MODEL SOUNDINGS
SUGGEST SUBSTANTIAL DRYING AT THE MID AND UPPER LEVELS AS THE
FRONT MOVES OFFSHORE...SO EXPECT BULK OF PRECIP WILL HAVE MOVED
OFFSHORE ON WEDNESDAY AS WELL.

&&

.LONG TERM /THURSDAY THROUGH MONDAY/...
AS OF 245 PM MONDAY...EASTERN EDGE OF OMEGA BLOCK SETTING UP LATE
IN THE WEEK WILL BE OVER THE CAROLINAS AS THE PERIOD BEGINS. THE
5H LOW/TROUGH WILL DRIVE A COLD FRONT ACROSS THE AREA THU WITH
FRONTAL CONVERGENCE AND INSTABILITY UNDER THE COLD POOL LIKELY
LEADING TO AT LEAST A FEW SHOWERS IN THE AREA. LACK OF DEEP
MOISTURE WILL LIMIT COVERAGE WITH NORTHERN LOCATIONS THE MOST
FAVORED. SIMILAR STORY...MINUS THE COLD FRONT...FRI AND POSSIBLY
SAT. MID LEVEL LOW/TROUGH OVERHEAD GENERATING INSTABILITY SHOWERS
IN THE AFTERNOON BUT DEEP NORTHWEST FLOW WILL LIMIT AVAILABLE
MOISTURE...KEEPING COVERAGE LIMITED TO SLIGHT CHANCE AT BEST.
TEMPERATURES THU AND FRI WILL RUN BELOW CLIMO.

BLOCK STARTS BREAKING DOWN/SHIFTING EAST ON SAT WITH 5H RIDGE
MOVING INTO THE REGION FOR SUN AND MON. DEEP WEST TO NORTHWEST
FLOW CONTINUES WHICH PREVENTS MEANINGFUL MOISTURE RETURN AND SETS
UP DOWNSLOPE FLOW IN ADDITION TO SUBSIDENCE UNDER THE RIDGE ALOFT.
TEMPERATURES SAT NEAR CLIMO BUT THEN ABOVE CLIMO SUN AND MON.
WEAKENING OF THE 5H RIDGE AND CONTINUED EASTWARD MOVEMENT OF THE
RIDGE AXIS MON WILL ALLOW FOR SOME MOISTURE RETURN AS THE PERIOD
ENDS. DO NOT THINK PRECIP WILL FALL MON DO EXPECT AN INCREASE IN
CLOUD COVER.

&&

.AVIATION /06Z TUESDAY THROUGH SATURDAY/...
AS OF 06Z...PERIODS OF MVFR/IFR IN ISOLATED TO SCATTERED SHOWERS
AND THUNDERSTORMS THROUGH THE VALID TAF CYCLE...AS AN UNSETTLED
UPPER TROUGH APPROACHES THE EAST COAST.

POCKETS OF IFR CIGS IN LOW-BASED STRATUS EXPECTED THROUGH 13Z
TODAY. S WINDS 6-11 KTS OVERNIGHT WILL BECOME SW AFTER DAYBREAK
WITH HIGHER GUSTS TO 21 KTS. SCATTERED TSTMS MAY BECOME STRONG TO
SEVERE IN THE AFTERNOON TO EVENING...WITH ISOLATED SURFACE WIND
GUSTS ABOVE 40-50 KT IN +TSRA.

EXTENDED OUTLOOK...MVFR/IFR POSSIBLE FROM CONVECTION THROUGH
EARLY WEDNESDAY. VFR WEDNESDAY THROUGH FRIDAY...WITH SCT 4SM SHRA
THU AND FRI.

&&

.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 120 AM TUESDAY...NO CHANGES WITH THE EARLY MORNING UPDATES.

SMALL CRAFT SHOULD EXERCISE CAUTION CONDITIONS ARE EXPECTED
OVERNIGHT FOR ALL THE WATERS. SW WINDS OF 15 TO 20 KT WITH GUSTS
TO 25 KT WILL BUILD SEAS TO 4 TO 5 FT. THE PRESSURE GRADIENT WILL
TIGHTEN AHEAD OF AN APPROACHING COLD FRONT WITH THE LOW-LEVEL
WINDS INCREASING. THE MARINE ENVIRONMENT SHOULD BE WELL MIXED
OVERNIGHT. SHOWERS AND THUNDERSTORMS ARE EXPECTED TO BE NUMEROUS
LATE TONIGHT AND TUE MORNING.

SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
AS OF 245 PM MONDAY...A COLD FRONT APPROACHING THE WATERS WILL
LIKELY MAKE IT TO THE COAST AROUND DAYBREAK ON WEDNESDAY. WINDS
WILL STAY SW THROUGH TUESDAY AND ALTHOUGH DO NOT EXPECT ANY
ADVISORIES TO BE POSTED...CONDITIONS MAY WARRANT FURTHER EXERCISE
CAUTION HEADLINES. CONDITIONS IMPROVE ON WEDNESDAY AS THE FRONT
MOVES OVER OR NEAR THE WATERS. IT IS LIKELY THAT SHOWERS AND
THUNDERSTORMS WILL IMPACT THE WATERS ON TUESDAY AND POSSIBLY ALSO
WEDNESDAY.

LONG TERM /THURSDAY THROUGH SATURDAY/...
AS OF 245 PM MONDAY...PERIOD WILL BE DOMINATED BY WEST TO
NORTHWEST FLOW...WITH SPEEDS PEAKING LATE THU AND THU NIGHT
FOLLOWING THE PASSAGE OF A COLD FRONT. PINCHED GRADIENT AND COLD
ADVECTION AS HIGH BUILDS IN FROM THE WEST WILL PUSH WIND SPEEDS
CLOSE TO 20 KT LATE THU AND THU NIGHT. GRADIENT STARTS TO SLOWLY
RELAX FRI WITH WINDS DROPPING FROM 15 TO 20 KT IN THE MORNING TO
10 TO 15 KT BY LATE AFTERNOON. NORTHWEST FLOW REMAINS 10 TO 15 KT
INTO SAT BEFORE DROPPING CLOSER TO 10 KT LATE SAT AFTERNOON. SEAS
PEAK THU NIGHT...RUNNING 3 TO 5 FT DUE TO THE STRONG OFFSHORE
FLOW. SEAS START TO SUBSIDE ON FRI...DROPPING TO 2 TO 4 FT IN THE
AFTERNOON WITH 2 FT OR LESS EXPECTED BY SAT.

&&

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

&&

$$

SYNOPSIS...COLBY
NEAR TERM...RJD/8
SHORT TERM...REK
LONG TERM...III
AVIATION...SGL/MJC



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