Area Forecast Discussion
Issued by NWS Wilmington, NC

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FXUS62 KILM 061723
AFDILM

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WILMINGTON NC
123 PM EDT WED MAY 6 2015

.SYNOPSIS...
A LOW PRESSURE SYSTEM ORGANIZING NEAR THE BAHAMAS WILL LIFT NORTH
TODAY AND THEN MEANDER AND STRENGTHEN OFF THE SOUTHEAST COAST INTO
THE WEEKEND. THIS SYSTEM MAY TRACK VERY CLOSE TO THE
COAST...CREATING PERIODS OF GUSTY WINDS AND HEAVY RAINFALL
THURSDAY THROUGH SATURDAY. THIS LOW PRESSURE WILL WEAKEN BUT MAY
CONTINUE TO CREATE UNSETTLED WEATHER THROUGH MONDAY.

&&

.NEAR TERM /THROUGH TONIGHT/...
AS OF 130 PM WEDNESDAY...SATELLITE AND LONG RANGE RADAR IMAGERY
SHOW AN EXPANSIVE AREA OF SHOWERS AND THUNDERSTORMS INUNDATING
THE WATERS FROM ROUGHLY THE CAPE FEAR AREA SOUTH TO ACROSS THE
FLORIDA PENINSULA. GUIDANCE IS IN GOOD AGREEMENT IN THE AREA
SHIFTING NORTH AND WESTWARD SLOWLY THROUGH THE AFTERNOON AND
OVERNIGHT AREAS. I HAVE INCREASED POPS FOR THE LATE NIGHT/EARLY
MORNING HOURS FOR ALL AREAS AS EVEN THE GFS SHOWS SOME LIGHT RAIN
WEST OF I-95. OVERNIGHT LOWS SHOULD REMAIN JUST A COUPLE OF
DEGREES ABOVE THE LATEST GUIDANCE WITH A MIXED BOUNDARY LAYER AND
OVERCAST SKIES. NHC HAS CANCELLED A RECONNAISSANCE FLIGHT OVER THE
SYSTEM FOR THIS AFTERNOON. HOWEVER THEY CONTINUE TO EXPECT
DEVELOPMENT OVER THE NEXT COUPLE OF DAYS AND A NEW TROPICAL
WEATHER OUTLOOK WILL BE ISSUED THIS EVENING.

&&

.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 300 AM WEDNESDAY...A TROUGH OF LOW PRESSURE CURRENTLY
BLOSSOMING OFF THE SOUTH FLORIDA COAST IS EXPECTED TO INTENSIFY OFF
THE SOUTHEAST COAST THROUGH LATE WEEK...AND POSSIBLY DEVELOP SOME
TROPICAL OR SUBTROPICAL CHARACTERISTICS AS IT MEANDERS IN THE
VICINITY. UNFORTUNATELY...EVEN AT THIS TIME RANGE THERE IS MUCH
LOWERED CONFIDENCE THAN USUAL...BUT HOPEFULLY SOME OF THIS WILL BE
IMPROVED TODAY AS NHC IS PLANNING ITS FIRST RECON FLIGHT INTO THE
SYSTEM.

THAT BEING SAID...I STILL NEED TO WRITE A DISCUSSION AND CREATE A
FORECAST EVEN WITH LIMITED CONFIDENCE. THERE ARE A FEW THINGS WE CAN
GLEAN FROM THE SETUP AND FROM THE GUIDANCE...EVEN THOUGH WHOLESALE
CHANGES CANNOT BE MADE. THERE IS HIGH CONFIDENCE THAT A LOW PRESSURE
WILL DEVELOP...AND THAT IT WILL MEANDER SLOWLY NEAR THE COAST AS IT
GETS BLOCKED BY MID-LEVEL RIDGING TO THE NORTH. THERE IS HIGH
CONFIDENCE THAT IT WILL RETROGRADE WEST OR EVEN SW THU/FRI...AND
THERE IS HIGH CONFIDENCE THAT PERIODS OF RAINFALL...POSSIBLY HEAVY
AT TIMES...WILL IMPACT AT LEAST THE COASTAL SECTIONS OF THE CWA.
BEYOND THAT HOWEVER...TIMING...TRACK...INTENSITY...AND OTHER IMPACTS
(WIND...CONVECTION...DURATION) ARE STILL VERY MUCH IN QUESTION. THE
NAM IS LIKELY TOO STRONG AND TOO FAR NORTH...WHILE THE GFS LIES ON
THE WEAK/SOUTH END OF THE ENVELOPE. AN INTERMEDIATE SOLUTION OF THE
ECMWF/CMC MAY BE MOST PRUDENT AT THIS POINT THEN. WILL CONTINUE WITH
THE INHERITED FORECAST AND SHOW HIGHEST POP ON FRIDAY...BUT
OTHERWISE ATTM EXPECT DETERIORATING CONDITIONS THURSDAY INTO FRIDAY
WITH AT LEAST INCREASING WINDS AND PERIODS OF SHOWERS...SOME OF
WHICH AGAIN...MAY BE HEAVY AT TIMES.

HIGH TEMPS WILL LIKELY REMAIN JUST BELOW CLIMO IN THE TROPICAL AIR
MASS DUE TO RAIN AND CLOUDS...WITH HIGHS STAYING IN THE MID TO UPR
70S. MINS WILL STAY ABOVE CLIMO AS GUSTY WARM WINDS AND CLOUDS KEEP
LOWS WELL INTO THE 60S.

&&

.LONG TERM /SATURDAY THROUGH TUESDAY/...
AS OF 300 AM WEDNESDAY...HOW THE LONG TERM DEVELOPS WILL HINGE
STRONGLY ON WHAT OCCURS DURING THE SHORT TERM. A LOW PRESSURE
SYSTEM...POSSIBLE SUBTROPICAL STORM...WILL STILL BE SOMEWHERE IN THE
VICINITY...POSSIBLY INLAND...POSSIBLY STILL OFFSHORE...DEPENDING ON
WHICH MODEL IS PREFERRED. FAVOR THE SLOWER GUIDANCE AT THIS
POINT...BUT WITH SO MUCH UNCERTAINTY STILL IN THE FORECAST AS THE
SYSTEM MEANDERS BENEATH AN UPPER RIDGE...WILL AGAIN MAKE ONLY
MINIMAL CHANGES TO THE EXTENDED. UNSETTLED WEATHER ASSOCIATED WITH
THIS LOW PRESSURE MAY PERSIST INTO MONDAY WITH PERIODS OF RAIN AND
WIND...BEFORE AN UPPER TROUGH FINALLY KICKS THE SYSTEM OFF TO THE
NORTHEAST AHEAD OF A COLD FRONT WHICH WILL APPROACH AT THE END OF
THE PERIOD. TEMPS SAT-MON WILL HOVER AROUND CLIMO...DEPENDING ON HOW
THE LOW EVOLVES...BUT SHOULD WARM QUITE A BIT AHEAD OF THE COLD
FRONT EARLY NEXT WEEK.

&&

.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
AS OF 18Z...VFR THIS AFTERNOON AND EVENING. A SURFACE HIGH PRESSURE
AXIS EXTENDING WEST ACROSS THE TERMINALS WILL SHIFT TO THE NORTH AS
A SURFACE LOW APPROACHES FROM THE SOUTH. LOWERING HIGH LEVEL CIGS
EXPECTED THIS AFTERNOON AND EVENING. DESPITE A MOIST E-ENE ONSHORE
LOW-LEVEL WIND FLOW THIS AFTERNOON ANY LOW CLOUDS WILL REMAIN
SCATTERED THIS AFTERNOON AND EVENING DUE TO SUBSIDENCE AHEAD OF THE
LOW. WINDS WILL GRADUALLY BECOME NE TONIGHT. CONFIDENCE IS
INCREASING THAT FLIGHT CONDITIONS WILL DECREASE TO MVFR AT THE
COASTAL TERMINALS AFTER MIDNIGHT AND THE INLAND TERMINALS AFTER
SUNRISE AS RAIN OVERSPREAD THE TERMINALS. SOME EMBEDDED ELEVATED
CONVECTION WILL ALSO BE POSSIBLE MAINLY AT THE COASTAL
TERMINALS...BUT ANY THUNDERSTORMS ARE EXPECTED TO BE ISOLATED.
CONFIDENCE OF IFR IS LOW ATTM DUE TO UNCERTAINTY OF THE SPEED AND
DIRECTION OF MOVEMENT OF THE LOW...AS WELL AS THE TIMING AND
INTENSITY OF ANY RAIN BANDS MOVING ONSHORE AHEAD OF IT.

EXTENDED OUTLOOK...RAIN/MVFR. TEMPO IFR IN HEAVIER SHOWERS HIGHEST
CONFIDENCE COASTAL TERMINALS. BECOMING VFR/SHOWERS SUNDAY. VFR
ISOLATED SHOWERS MON.

EXTENDED OUTLOOK...RAIN/MVFR. TEMPO IFR IN HEAVIER SHOWERS HIGHEST
CONFIDENCE COASTAL TERMINALS. BECOMING VFR SUNDAY.

&&

.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 130 PM WEDNESDAY...NORTHEAST WINDS WILL CONTINUE TO INCREASE
DURING THE AFTERNOON AND OVERNIGHT HOURS AS LOW PRESSURE DEVELOPS
WELL SOUTH OF THE AREA AND MOVES NORTHWARD. I HAVE WINDS
INCREASING FROM THE CURRENT 10-15...WHICH THE LATEST BUOY REPORTS
SHOW ARE ON THE VERY HIGH END TO A RESPECTABLE 20-25 KNOTS BY
EARLY THURSDAY. I HAVE INCREASED SEAS AS WELL PER THE LATEST
OBSERVATIONS WHICH ARE NOW JUST UNDER FIVE FEET AT 41013 AND
ALMOST THREE FOUR FEET AT 41110. I HAVE ADJUSTED THE START TIME OF
THE SMALL CRAFT ADVISORY TO 6 PM.

SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 300 AM WEDNESDAY...SMALL CRAFT ADVISORY HAS BEEN HOISTED
BEGINNING TONIGHT...AND WILL PERSIST THROUGH AT LEAST 8PM FRIDAY
NIGHT AS A LOW PRESSURE DEVELOPS AND STRENGTHENS OFFSHORE. THERE
IS STILL CONSIDERABLE UNCERTAINTY EVEN IN THE SHORT TERM...BUT IT
APPEARS A LOW PRESSURE SYSTEM DEVELOPING OFF THE FLORIDA COAST
WILL MOVE NORTH AND THEN STALL NEAR THE LOCAL WATERS THU/FRI. AS
IT MEANDERS IN THE VICINITY IT WILL CAUSE INCREASING WINDS FROM
THE E/NE...POSSIBLY BECOMING NORTH LATE ACROSS THE SOUTHERN
WATERS...ALL AT SPEEDS OF 15-20 KTS. THESE COULD BECOME HIGHER (OR
LOWER) DEPENDING ON HOW THE LOW PRESSURE EVOLVES.
REGARDLESS...MARINE CONDITIONS WILL BECOME POOR AS THESE INCREASED
WINDS AND AN AMPLIFYING SWELL PUSH SEAS UP TO 4-8 FT THROUGH MOST
OF THE PERIOD. SOME IMPROVEMENT IS CURRENTLY FORECAST LATE...BUT
THIS MAY CHANGE ONCE THE TRACK OF THE LOW BECOMES MORE CLEAR...AND
MARINERS SHOULD KEEP APPRISED OF THIS EVOLVING SITUATION.

LONG TERM /SATURDAY THROUGH SUNDAY/...
AS OF 300 AM WEDNESDAY...LOW PRESSURE WILL LIKELY STILL BE
IMPACTING THE AREA THROUGH THE WKND...BUT HOPEFULLY IN A WEAKENED
STATE. UNCERTAINTY REMAINS THROUGH THE EXTENDED...AND WHILE
CONDITIONS ARE NOT CURRENTLY FORECAST TO BE HEADLINE
CRITERIA...THEY WILL REMAIN HAZARDOUS WITH A VARIETY OF WIND
DIRECTIONS AND SPEEDS POSSIBLE AS THE LOW CENTER MOVES...POSSIBLY
DIRECTLY ACROSS THE COASTAL WATERS. ATTM EXPECT THE NC WATERS TO
EXPERIENCE WORSE CONDITIONS THAN OFF THE SC COAST...BUT
AGAIN...MUCH STILL MAY CHANGE. WINDS OF 15-20 KTS FROM THE EAST
ARE LIKELY NORTH OF THE LOW...WITH WEAKER N/NW WINDS ON THE BACK
SIDE OF THE SYSTEM. WAVE HEIGHTS WILL REMAIN IN THE 3-5 FT RANGE
AS A HIGH AMPLITUDE SWELL PERSISTS EVEN AS WINDS BEGIN TO EASE.

&&

.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 6 PM THIS EVENING TO 8 PM EDT FRIDAY
     FOR AMZ250-252-254-256.

&&

$$
SYNOPSIS...SHK
NEAR TERM...SHK
SHORT TERM...JDW
LONG TERM...JDW
AVIATION...SHK



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