Area Forecast Discussion
Issued by NWS Wilmington, NC

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FXUS62 KILM 011417
AFDILM

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WILMINGTON NC
1017 AM EDT FRI AUG 1 2014

.SYNOPSIS...
A COASTAL FRONT JUST OFFSHORE WILL PUSH INLAND TODAY...THEN
WILL STALL OVER THE AREA FROM THIS AFTERNOON THROUGH THE WEEKEND.
THIS WILL BRING GOOD RAIN CHANCES...WITH PERIODS OF HEAVY RAINFALL
POSSIBLE TODAY THROUGH MONDAY. MORE SEASONABLE WEATHER WILL DEVELOP
THE MIDDLE OF NEXT WEEK.

&&

.NEAR TERM /THROUGH TONIGHT/...
AS OF 10 AM FRIDAY...SLOW WESTWARD DRIFT OF COASTAL TROUGH WILL
CONTINUE TODAY AS GULF MOISTURE SPREADS OVER THE SOUTHEAST. MARGINAL
INSTABILITY COMBINED WITH CONVERGENCE ALONG THE TROUGH AND ABUNDANT
MOISTURE...12Z SOUNDINGS FROM MHX SHOW PRECIPITABLE WATER VALUES
OVER 2 INCHES...WILL LEAD TO WIDESPREAD SHOWERS AND THUNDERSTORMS
TODAY AND TONIGHT. INITIAL ACTIVITY WILL BE FOCUSED NEAR THE COAST
BUT AS THE TROUGH MOVES INLAND AND SURFACE HEATING OCCURS PRECIP
COVERAGE SHOULD EXPAND. ALTHOUGH THE SEVERE WEATHER THREAT WILL BE
LOW IT WILL NOT BE NONZERO. STORMS MOVING ONSHORE WILL HAVE
POTENTIAL TO SPIN UP A BRIEF/WEAK TORNADO AND DEEPEST CONVECTION
WOULD HAVE POTENTIAL FOR WET MICROBURSTS. HOWEVER THE MAIN THREAT
WILL BE FLOODING WITH FORECAST SOUNDINGS SHOWING DEEP WARM LAYER AND
PLENTY OF MOISTURE THROUGH THE DAY. STORM MOTIONS SHOULD BE OVER 10
KT BUT TRAINING STORMS WILL BE A CONCERN. GIVEN THESE FACTORS...AND
THE EXCEEDINGLY WET PAST FEW WEEKS...HAVE DECIDED TO RAISE A FLOOD
WATCH FOR ALL OF THE AREA. CLOUD COVER AND PRECIP WILL KEEP HIGHS
BELOW CLIMO THIS AFTERNOON BUT HELP KEEP LOWS NEAR TO ABOVE CLIMO
OVERNIGHT.

&&

.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
AS OF 330 AM FRIDAY...THE WEEKEND CONTINUES TO LOOK QUITE WET AND
COOL...EVEN AS THE PERSISTENT DEEP UPPER TROUGH BEGINS TO WEAKEN
ACROSS THE EAST. ALTHOUGH THE TROUGH WILL BEGIN TO
FILL...RELATIVELY LOWERED THICKNESSES WILL PERSIST AS A SHORTWAVE
MOVES ACROSS THE OH VLY AND INTO THE MID-ATLANTIC. THIS WILL HAVE
THE EFFECT OF KEEPING THE TROUGH AS THE DRIVING INFLUENCE
ALOFT...WITH CONTINUED MOIST ADVECTION ON S/SW MID-LEVEL WINDS. AT
THE SURFACE...COASTAL TROUGH WHICH MOVES INLAND BEFORE THE
PERIOD...WILL STALL ACROSS...OR JUST INLAND...OF THE CWA...PUMPING
MOIST SE WINDS INTO THE AREA AND SERVING AS A CONVERGENT FOCUS FOR
SHOWERS AND STORMS. ALL THIS COMBINES WITH PERSISTENT UPPER
DIFFLUENCE WITHIN THE ENTRANCE REGION TO A JET STREAK ACROSS THE
NORTHEAST...AND THE WKND LOOKS TO BE PRETTY MUCH A WASH OUT. MOS
NUMBERS ARE ALREADY CATEGORICAL...BUT WITH NO SINGLE TIME PERIOD
FAVORED...WILL CONTINUE WITH HIGH-LIKELY FOR THE WKND. QPF COULD
BE QUITE SUBSTANTIAL AS WELL...WITH 1-3" OF RAIN EXPECTED...ALONG
WITH ISOLATED HIGHER TOTALS.

THE CLOUDS...RAIN...AND LOWERED THICKNESSES WILL KEEP HIGHS BELOW
NORMAL FOR EARLY-AUGUST...BUT AT THE SAME TIME MAINTAIN NORMAL OR
SLIGHTLY ABOVE NORMAL LOWS. EXPECT HIGHS IN THE LOW 80S BOTH
DAYS...AND LOWS IN THE LOW 70S.

&&

.LONG TERM /MONDAY THROUGH THURSDAY/...
AS OF 230 PM THURSDAY...ATYPICALLY WELL DEFINED (FOR THE TIME OF
YEAR) MID AND UPPER LEVEL TROUGHINESS TO OUR WEST ON SUNDAY.
DECAYING SURFACE BOUNDARY TO PROVIDE LOW LEVEL LIFT...WHICH WILL
THEN BE AIDED BY MID LEVEL PVA AND UPPER DIVERGENCE ASSOC WITH
RIGHT ENTRANCE OF UPPER JET STREAK ACROSS NORTHEAST AND MID
ATLANTIC. AND WHILE RAIN CHANCES SEEM TO WARRANT LIKELY POPS
MODELS ARE NOT SUGGESTIVE OF HIGH QPF AMOUNTS. THIS MAY BE DUE TO
IT BEING SUCH A CLOUDY DAY THAT VERY LITTLE INSTABILITY MANAGES TO
DEVELOP SAVE FOR PERHAPS ALONG THE IMMEDIATE COAST. THESE PLAYERS
ALL REMAIN NEARLY IN PLACE HEADING INTO MONDAY ALTHOUGH ALL OF
THEM WEAKEN. LOOKING FOR ANOTHER DAY OF HIGH POPS AND SUPPRESSED
AFTERNOON TEMPS. TUESDAY SHOULD BRING LOWER RAIN CHANCES BUT STILL
ONES THAT ARE HIGHER THAN NORMAL. THE UPPER JET CONTINUES TO
WEAKEN AND LIFT OUT TO THE NORTHEAST WHILE THE MID LEVEL TROUGH
WEAKENS...BUT ALSO SENDS ITS REMAINING VORT CENTER ACROSS THE
CAROLINAS. IN RESPONSE TO THIS THE GFS STRAIGHTENS THE PIEDMONT
TROUGH AT THE SURFACE. WE ALSO MAY SEE A BIT MORE SUNSHINE IN
CONTRAST TO THE EARLY PARTS OF THE PERIOD. TUESDAY MAY THUS BE A
DAY WHERE WE TRANSITION TO MORE SCATTERED AND DEEPER CONVECTION
ESP IF TEMPS START BOUNCING BACK TOWARDS CLIMO. WEDNESDAY AND
THURSDAY LOOK SEASONABLE WITH RESPECT TO BOTH TEMPERATURES AND
AREAL COVERAGE OF CONVECTION. MID LEVEL FLOW SHOULD BE OF A DRIER
WESTERLY DIRECTION WHILE SOME SEMBLANCE OF A PIEDMONT TROUGH
REMAINS.

&&

.AVIATION /14Z FRIDAY THROUGH TUESDAY/...
AS OF 12Z...LOOKS LIKE MOST OF THE CONVECTION WILL WAVE NORTH OF ILM
BY 13Z...AND MAY AFFECT LBT FOR THE FIRST COUPLE OF HOURS THIS
MORNING. THERE MAY BE A BIT OF A LULL IN THE ACTION AS THIS FIRST
IMPULSE MOVES NORTH OF THE REGION. WITH PWATS AROUND 2 INCHES AND A
LOW LFC...JUST A BIT OF HEATING WILL LIKELY POP THIS AGAIN AROUND
MIDDAY...CONTINUING THROUGH THE AFTERNOON HOURS. CONVECTION WILL
SLOWLY WEAKEN THROUGH THE EVENING HOURS...HOWEVER WEAK IMPULSES
TONIGHT COULD PRODUCE CONVECTION AT ALMOST ANY TIME. SOUTHEAST FLOW
THROUGH THE PERIOD.

EXTENDED OUTLOOK...SHRA/TSRA LIKELY WITH PERIODS OF MVFR
CONDITIONS THROUGH MON AS A FRONT STALLS AND FINALLY DISSIPATES
OVER THE EASTERN CAROLINAS. A CHANCE OF SHOWERS CONTINUES ON TUE.

&&

.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 10 AM FRIDAY...EAST TO SOUTHEAST FLOW WILL CONTINUE TODAY AND
TONIGHT AS WEAK COASTAL TROUGH MOVES ONSHORE. GRADIENT WILL KEEP
WIND SPEEDS 10 TO 15 KT FOR MUCH OF THE PERIOD. PROLONGED ONSHORE
FLOW WILL KEEP SEAS IN THE 3 TO 4 FT RANGE THROUGH THE END OF THE
PERIOD.

SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
AS OF 330 AM FRIDAY...COASTAL TROUGH WILL STALL INLAND OF THE
WATERS DURING THE WEEKEND...WHILE HIGH PRESSURE RIDGE EXPANDS
ACROSS THE ATLANTIC TO THE EAST. THIS LEAVES THE COASTAL WATERS
PINCHED BETWEEN THE TWO...AND ALTHOUGH THE GRADIENT WILL REMAIN
RELATIVELY WEAK...WINDS WILL BE 10-15 KTS BOTH DAYS...WITH A S/SE
DIRECTION PREDOMINANT. SEAS WILL BE 2-4 FT THROUGH THE
WEEKEND...WITH A SE GROUND SWELL AMPLIFYING...COMBINING WITH A
SOUTHERLY WIND WAVE TO FORM THE ENTIRE WAVE SPECTRUM.

LONG TERM /SUNDAY THROUGH TUESDAY/...
AS OF 230 PM THURSDAY...LIGHT SOUTHERLY WINDS ON SUNDAY WITH
FRONTAL BOUNDARY JUST INLAND OF THE COAST. WIND CHOP WILL BE
COINCIDENT WITH 11 SECOND SOUTHEASTERLY SWELL. THE WEAKENING
BOUNDARY WILL MOVE FURTHER INLAND FOR THE REMAINDER OF THE PERIOD
AND THE WEST ATLANTIC HIGH POKES A BIT WESTWARD FURTHER INTO THE
CAROLINAS. THIS COULD LEAD TO AN OCCASIONAL INCREASE IN FLOW BY A
FEW KNOTS AND ALSO A SLIGHT VEER FROM S TO SW.

&&

.ILM WATCHES/WARNINGS/ADVISORIES...
SC...FLOOD WATCH THROUGH SUNDAY EVENING FOR SCZ017-023-024-032-033-
     039-053>056.

NC...FLOOD WATCH THROUGH SUNDAY EVENING FOR NCZ087-096-099-105>110.

MARINE...NONE.

&&

$$

NEAR TERM...III
SHORT TERM...JDW
LONG TERM...MBB
AVIATION...43






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