Area Forecast Discussion
Issued by NWS Wilmington, NC

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000
FXUS62 KILM 161720
AFDILM

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WILMINGTON NC
1220 PM EST TUE DEC 16 2014

.SYNOPSIS...
TEMPERATURES WILL RISE WELL ABOVE NORMAL THIS AFTERNOON AHEAD OF AN
APPROACHING COLD FRONT THAT WILL CROSS THE COAST TONIGHT.
SEASONABLY COOL AND FAIR WEATHER WILL FOLLOW WEDNESDAY THROUGH
FRIDAY. AN APPROACHING STORM SYSTEM COULD BRING WET CONDITIONS
DURING THE UPCOMING WEEKEND.

&&

.NEAR TERM /THROUGH TONIGHT/...
AS OF 1230 PM TUESDAY...PRE FRONTAL BAND OF BROKEN SHOWERS CONTINUES
TO MOVE EASTWARD AND IS A LITTLE MORE CONCENTRATED TO THE NORTH AS
EXPECTED. BASED ON THE NAM...I HAVE BUMPED POPS UP SLIGHTLY FOR
LATER THIS AFTERNOON FOR THE CAPER FEAR REGION. THERE IS JUST ENOUGH
MOISTURE POOLING AND A SHORTWAVE ALOFT TO GIVE A BRIEF BOOST TO THE
FORCING. THERE IS A LITTLE QPF ASSOCIATED WITH THE ACTUAL FRONT
LATER AND HAVE EXTENDED POPS A LITTLE LATER IN THE EVENING. USED THE
COOLER MET NUMBERS FOR THE OVERNIGHT LOWS.

&&

.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
AS OF 3 AM TUESDAY...PROGRESSIVE MID LEVEL PATTERN AND LOW LEVEL DRY
AIR WILL KEEP THE SOUTHEAST DRY THROUGH THE PERIOD. INCREASING
MOISTURE ALOFT WILL MANIFEST AS AN INCREASE IN CLOUD COVER LATE WED
NIGHT AND THU BUT DRY AIR BELOW 700MB AND LOW LEVEL SUBSIDENCE RULE
OUT ANY PRECIP CHANCES.

WEAK SHORTWAVE PASSES NORTH OF THE AREA ON THU AND THE RESULTING
INCREASE IN MOISTURE BETWEEN 600 AND 700MB SHOULD PRODUCE A MID
CLOUD DECK DURING THE AFTERNOON. THIS CLOUD...WHILE NOT RAIN
BEARING...WILL COOL TEMPS A BIT AND HIGHS ARE LIKELY TO END UP A
DEGREE OR 2 SHORT OF CLIMO IN MOST PLACES. COOLEST AREAS WILL BE
ACROSS THE NORTHERN TIER WHERE CLOUDS LIKELY TO BE THICKEST AND MOST
PREVALENT. HIGH CLOUDS WILL HELP KEEP LOWS NEAR CLIMO BOTH NIGHTS.

&&

.LONG TERM /FRIDAY THROUGH MONDAY/...
AS OF 3 AM TUESDAY...SOUTHERN STREAM SYSTEM STILL PROGGED TO AFFECT
THE SOUTHEAST FRI NIGHT THROUGH SAT NIGHT. A LOT ABOUT THIS SYSTEM
REMAINS UNCERTAIN AND CONFIDENCE CONTINUES TO RUN LOW. GUIDANCE
CONTINUES TO HAVE RUN TO RUN CONSISTENCY PROBLEMS WITH SOLUTIONS
RANGING FROM INTERACTION WITH A NORTHERN STREAM SHORTWAVE AND A WELL
DEVELOPED SURFACE LOW CROSSING THE LOCAL AREA AND THEN TRAVELING UP
THE EAST COAST TO A WEAK WAVE OPENING UP AS IT LIFTS NORTHEAST AND
DRAGS A COLD FRONT ACROSS THE AREA.

DESPITE THE UNCERTAINTY SOME DETAILS CAN BE GLEANED FROM THE CHAOS.
MID LEVEL FLOW OVER THE SOUTHERN CONUS WILL TRANSITION FROM
PROGRESSIVE TO AMPLIFIED WITH DEEP SOUTHWEST FLOW ADVECTION MOISTURE
OVER THE CAROLINAS. EVEN THE DRIEST SOLUTIONS SHOW ABUNDANT DEEP
MOISTURE WITH PRECIPITABLE WATER VALUES APPROACHING 1.25 INCH. IT
ALSO APPEARS THAT REGARDLESS OF THE TRACK OR INTENSITY OF THE
SURFACE AND MID LEVEL FEATURES THERE WILL NOT BE ANY PRECIP TYPE
ISSUES. BEST PRECIP CHANCES REMAIN LATE FRI NIGHT INTO SAT EVENING
WHEN ISENTROPIC LIFT AND MOISTURE ARE ON THE INCREASE. THERE SHOULD
ALSO BE SOME ENHANCEMENT FROM PVA AHEAD OF THE SHORTWAVE ALONG WITH
THE POSSIBILITY OF SURFACE CYCLOGENESIS. INHERITED FORECAST THINKING
REMAINS VALID AND PLAN ONLY MINIMAL CHANGES TO PRECIP FORECAST.

NEXT WEEK STARTS OFF DRY AS THE SOUTHERN STREAM SYSTEM EXITS. MEDIUM
RANGE GUIDANCE IS HINTING AT TRAILING COLD FRONT ENDING UP PARALLEL
TO STEERING FLOW WITH THE BOUNDARY STALLED SOMEWHERE OFF THE
SOUTHEAST COAST. AS HAS BEEN THE CASE LATELY THERE ARE BIG
DIFFERENCES BETWEEN THE GFS/ECMWF WITH RESPECT TO THE LOCATION OF
THE BOUNDARY AND ITS IMPACT ON THE CAROLINAS. FOR NOW DO NOT PLAN
ANY MAJOR CHANGES TO INHERITED DRY FORECAST FOR NEXT WEEK.

TEMPS NEAR CLIMO EARLY IN THE PERIOD WILL TREND BELOW CLIMO NEXT
WEEK. THERE WILL BE POTENTIAL FOR TEMPS ABOVE AND BELOW CLIMO
DEPENDING ON HOW THE WEEKEND PLAYS OUT. THE POSSIBILITY OF SURFACE
LOW CROSSING THE AREA SAT INTO SAT NIGHT COULD LEAD TO A WIDE RANGE
IN TEMPS ACROSS THE AREA. A STRONGER LOW WOULD ENHANCE WARMING AHEAD
OF THE LOW AS WELL AS ENHANCING COLD ADVECTION IN ITS WAKE SUN. ONCE
AGAIN FEEL MAKING LARGE CHANGES GIVEN THE LOW CONFIDENCE AND LACK OF
PREFERRED SOLUTION WOULD BE POINTLESS SO WILL CONTINUE WITH
INHERITED FORECAST.

&&

.AVIATION /17Z TUESDAY THROUGH SATURDAY/...
AS OF 18Z...MODERATE SOUTHWEST FLOW THIS AFTERNOON AHEAD OF THE WEAK
COLD FRONT. SCATTERED CONVECTION WILL CONTINUE TO MOVE INTO THE
REGION THROUGH THE AFTERNOON HOURS. THE NAM IS MORE
PESSIMISTIC...PARTICULARLY AT THE INLAND TERMINALS. THERE WILL BE
ABOUT A TWO HOUR WINDOW FOR PRECIP AS  THE FRONT PUSHES TO THE COAST
THIS EVENING. NOT A LOT OF DEEP MOISTURE...WITH INTERMITTENT MVFR
CONDITIONS WORST CASE. POST FRONTAL...LOOK FOR A GRADUAL WIND SHIFT
TO THE WEST NORTHWEST...LIKELY STAYING BELOW 10 KTS...CONTINUING
THROUGH THE END OF THE FORECAST PERIOD.

EXTENDED OUTLOOK...VFR WED THROUGH FRIDAY. A CHANCE OF RAIN ON
SATURDAY AND SUNDAY WITH POSSIBLE MVFR/IFR CONDITIONS.

&&

.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 1230 PM TUESDAY...SOUTHWESTERLY WINDS STARTING TO PICK UP AT
THE MOMENT ACROSS THE WATERS. BUOY OBSERVATIONS SHOW SPEEDS CURRENTLY
AROUND 10-12 KNOTS. SPEEDS WILL CONTINUE TO INCREASE THROUGHOUT THE
AFTERNOON ENDING UP IN THE MIDDLE OF A 20-25 KNOT RANGE BRIEFLY THIS
EVENING. FOR LATER TONIGHT...THE FRONT PUSHES THROUGH AROUND 0300
UTC WITH A WEST TO NORTHWEST FLOW ENSUING. WILL RAISE A SCEC AS
CONDITIONS SHOULD REMAIN BELOW SMALL CRAFT CRITERIA. SEAS WILL
INCREASE FROM CURRENT 1-2 FT. VALUES TO 3-5 FEET LATER THIS EVENING.

SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
AS OF 3 AM TUESDAY...WINDS WILL RETAIN AN OFFSHORE COMPONENT FOR
THE DURATION OF THE PERIOD WITH WATERS ON EAST SIDE OF ELONGATED
SURFACE HIGH EXTENDING SOUTH FROM CANADA. WINDS WILL VARY FROM
WEST TO NORTHWEST ON WED/WED NIGHT AND NORTHWEST TO NORTH THU/THU
NIGHT. GRADIENT WILL BE ON THE WEAK SIDE WITH SPEEDS AROUND 10 KT
FOR MUCH OF THE PERIOD. COMBINATION OF LIGHT WINDS AND OFFSHORE
FLOW WILL KEEP SEAS 2 FT OR LESS.

LONG TERM /FRIDAY THROUGH SATURDAY/...
AS OF 3 AM TUESDAY...HIGH PRESSURE FRI WILL YIELD TO A DEVELOPING
STORM SYSTEM SAT. SURFACE RIDGE AXIS TO THE WEST-NORTHWEST AND WEAK
GRADIENT WILL KEEP NORTH TO NORTHEAST FLOW 10 KT OR LESS THROUGH FRI
NIGHT. DEVELOPING LOW WILL MOVE ACROSS OR IN THE VICINITY OF THE
WATERS SAT. ALTHOUGH DETAILS REMAIN HAZY GRADIENT WILL TIGHTEN WITH
THE PASSING LOW AND WINDS WILL BE ON THE INCREASE...ESPECIALLY LATE
IN THE PERIOD AS THE LOW PULLS AWAY AND STRENGTHENS. CURRENT
FORECAST HAS WINDS HIGHLY VARIABLE SAT WITH OFFSHORE FLOW
APPROACHING A SOLID 20 KT LATE SAT NIGHT. SEAS AROUND 2 FT FRI COULD
BUILD AS HIGH AS 5 FT LATER SAT. ALTHOUGH NOT CURRENTLY FORECAST
CANNOT RULE OUT HEADLINE CRITERIA DEVELOPING LATE SAT OR SAT NIGHT.

&&

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

&&

$$
SYNOPSIS...III
NEAR TERM...SHK
SHORT TERM...III
LONG TERM...III
AVIATION...DL






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