Area Forecast Discussion
Issued by NWS Wilmington, NC

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000
FXUS62 KILM 171900
AFDILM

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WILMINGTON NC
300 PM EDT THU APR 17 2014

.SYNOPSIS...
HIGH PRESSURE WILL LINGER ACROSS THE CAROLINAS TODAY THROUGH
FRIDAY. RAIN CHANCES WILL INCREASE DURING THE WEEKEND AS A LOW
PRESSURE SYSTEM MOVES FROM THE GULF OF MEXICO AND INTO THE
ATLANTIC OCEAN. A WEAK PRESSURE PATTERN WILL SETTLE OVER THE
CAROLINAS FOR MUCH OF NEXT WEEK.

&&

.NEAR TERM /THROUGH TONIGHT/...
AS OF 3:00 PM THURSDAY...HIGH PRESSURE WEDGED ACROSS THE INTERIOR
CAROLINAS HAS WEAKENED SLIGHTLY THROUGH THE DAY...AND THIS TREND
WILL CONTINUE OVERNIGHT. THE 850-500 MB LAYER WILL REMAIN QUITE
DRY THROUGH THE OVERNIGHT PERIOD...HOWEVER UPPER-LEVEL MOISTURE
WILL BE ON THE INCREASE AHEAD OF A MID-LEVEL TROUGH SWEEPING
ACROSS THE PLAINS. DEWPOINTS HAVE SURGED INTO THE LOW-MID 40S AS
OF 18Z. THIS IS A FASTER RECOVERY OVER THE NORTHWESTERN TIER THAN
WAS PROGGED BY MOS...SO HAVE MADE SOME SLIGHT UPWARD ADJUSTMENTS
TO MIN TEMPS IN THAT AREA. GENERALLY A RANGE OF 43-49 EXPECTED
ACROSS THE CWA TONIGHT.

&&

.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
AS OF 3:00 PM THURSDAY...AN UPPER TROUGH WITH AN EMBEDDED AND
GRADUALLY DEEPENING LOW CENTER WILL MOVE EAST ACROSS THE GULF COAST
STATES THROUGH THE SHORT TERM. THIS FEATURE WILL DRIVE A
DEVELOPING SURFACE LOW AND ITS ASSOCIATED FRONTAL SYSTEM FROM THE
GULF OF MEXICO ACROSS FLORIDA ON FRIDAY AND ULTIMATELY INTO THE
OPEN WATERS OF THE ATLANTIC ON SATURDAY. GUIDANCE STILL DIFFERS ON
PLACEMENT AND DEVELOPMENT OF THIS SYSTEM SO ALTHOUGH I HAVE GONE
WITH A BLEND OF GUIDANCE HAVE LEANED TOWARDS THE GFS/ECMWF
SOLUTIONS...WHICH SEEMED MORE SIMILAR. WHICH MODELS ULTIMATELY
VERIFY MAKES A SIGNIFICANT DIFFERENCE AS FAR AS POPS AND QPF
GOES...WITH THE NAM BEING SIGNIFICANTLY THE DRYER SOLUTION. AS I
HAVE FAVORED THE GFS/ECMWF SOLUTIONS...I AM NOW EXPECTING A
SIGNIFICANT RAIN EVENT...WITH QPF EVENT TOTALS IN THE 1.0 TO 1.5
INCH RANGE. HEAVIEST RAIN WILL BE CENTERED AROUND FRIDAY NIGHT.

COOL NORTHEAST FLOW WILL KEEP MAXIMUM TEMPERATURES IN THE BELOW
NORMAL RANGE...WITH HIGHS IN THE MID 60S BOTH DAYS. EXTENSIVE
CLOUD COVER WILL HELP KEEP MINIMUM TEMPERATURES ON THE MILD
SIDE...WITH LOWS RANGING FROM THE UPPER 40S TO MID 50S BOTH DAYS.

&&

.LONG TERM /SUNDAY THROUGH THURSDAY/...
AS OF 3:00 PM THURSDAY...CUTOFF UPPER LOW TRAVERSING FLORIDA ON
SUNDAY. MODELS AT ODDS AS TO HOW FAR NORTH PRECIPITATION IS
SPREADING. HOWEVER EVEN THE MORE SUPPRESSED GUIDANCE IMPLIES THAT
COASTAL LOCATIONS SHOULD HAVE SOME SMALL RAIN CHANCES AND THE FCST
HAS BEEN ADJUSTED ACCORDINGLY. THERE IS A POSSIBILITY HOWEVER THAT
THIS WILL HAVE TO BE TRENDED UPWARDS BOTH WITH RESPECT TO POP
VALUES AND NORTHERN EXTENT. THIS SYSTEM PROGRESSES EASTWARD BY
MONDAY PAVING THE WAY FOR A DRIER AND MORE SEASONABLE AFTERNOON
WITH A WEAK SURFACE PRESSURE PATTERN AND ZONAL MID LEVEL FLOW. BY
TUESDAY THE STILL WEAK BL FLOW TURNS FROM NRLY TO SRLY BOOSTING
TEMPS. AN UPPER LOW AND COLD FRONT APPEAR SLATED FOR TUESDAY NIGHT
OR WEDNESDAY BUT IT SEEMS TOO MOISTURE-DEPRIVED TO YIELD
MEANINGFUL RAIN CHANCES.

&&

.AVIATION /18Z THURSDAY THROUGH TUESDAY/...
AS OF 12Z...11-3.9U SATELLITE IMAGERY INDICATE MARINE SC REMAINING
JUST OFFSHORE ATTM AS WINDS REMAIN NE THROUGH 3-4K. SURFACE WINDS
WILL BE NE 10-20 KTS THROUGH THE TAF VALID PERIOD. BUT AS WINDS JUST
ABOVE THE SURFACE BECOME MORE E AND SE TODAY...THIS WILL ALLOW THE
SC TO INITIALLY ADVECT INTO THE COASTAL TERMINALS...THEN DEVELOPING
AT THE INLAND TERMINALS LATER IN THE DAY. ALTHOUGH MVFR CIGS COULD
OCCUR THIS AFTERNOON AT THE COASTAL TERMINALS CONFIDENCE IS HIGHEST
THAT TEMPO VFR CIGS WILL OCCUR.

THIS EVENING AND OVERNIGHT THERE IS HIGHER CONFIDENCE CIGS WILL DROP
TO MVFR AS MOISTURE IN THE LOW LEVELS INCREASE. GFS MOS GUIDANCE
MOST AGGRESSIVE...AND IS INDICATING IFR STRATUS DEVELOPING AROUND
09Z...WITH NAM MOS GUIDANCE IS INDICATING A LOWER CHANCE OF
OCCURRENCE. SINCE BOTH MODEL SOUNDINGS SHOW A LOW LEVEL INVERSION
AROUND 1K...WILL INDICATE SCT IFR LEVEL STRATUS ATTM. ANY LIGHT RAIN
SHOULD REMAIN OFFSHORE OR WELL S OF THE TERMINALS THIS TAF VALID
PERIOD.

EXTENDED OUTLOOK...EXPECT AT LEAST PERIODS OF MVFR/IFR CIGS FRIDAY
AND SATURDAY AS WELL AS INCREASING RAIN CHANCES. MVFR CIGS COULD
LINGER INTO SUNDAY. VFR ON MONDAY.

&&

.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 3:00 PM THURSDAY...A RELATIVELY STRONG PRESSURE GRADIENT
WILL PERSIST ACROSS THE COASTAL WATERS THROUGH THE NIGHT BETWEEN A
STATIONARY SURFACE TROUGH WELL OFFSHORE AND A WEDGE OF HIGH
PRESSURE INLAND. THE WEDGE WILL WEAKEN SLIGHTLY
OVERNIGHT...HOWEVER THIS WILL RESULT IN VERY LITTLE CHANGE TO THE
STRENGTH OF THE GRADIENT AS SURFACE PRESSURES FALL OVER THE
NORTHERN GULF OF MEXICO. NORTHEAST WINDS ARE EXPECTED TO REMAIN IN
A 15-20 KT RANGE WITH SOME GUSTS TO 25 KTS...AND THIS WILL KEEP
SEAS OVER THE SMALL CRAFT ADVISORY THRESHOLD THROUGH THE DURATION
OF THE NIGHT.

SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
AS OF 3:00 PM THURSDAY...NORTHEAST FLOW WILL PERSIST THROUGH THE
SHORT TERM AS A FRONTAL SYSTEM EXITS THE GULF OF MEXICO AND MOVES
INTO THE OPEN WATERS OF THE ATLANTIC. WILL EXTEND THE SMALL CRAFT
ADVISORY THROUGH FRIDAY NIGHT AS MODERATE NORTHEASTERLY WINDS WILL
KEEP SEAS IN THE 4 TO 6 FT RANGE. ANTICIPATE THAT WE WILL FURTHER
EXTEND THE SCA INTO SATURDAY AS CONDITIONS ARE EXPECTED TO FURTHER
DETERIORATE WITH A DEEPENING LOW PRESSURE SYSTEM MOVING INTO THE
ATLANTIC.

LONG TERM /SUNDAY THROUGH MONDAY/...
AS OF 3:00 PM THURSDAY...SMALL CRAFT ADVISORY LIKELY IN EFFECT FOR
MOST OF THE PERIOD. GRADIENT WILL BE PINCHED BY A SLOW MOVING LOW
WHOSE UPPER LOW IS CUT OFF FROM THE MAIN JET STREAM FLOW. THIS
FEATURE PAIRED WITH A FAIRLY STRONG HIGH OFF NEW ENGLAND COAST
WILL LEAD TO STRONG WINDS THAT MAY EVEN OCCASIONALLY GUST TO GALE
FORCE ON SUNDAY OR SUNDAY NIGHT. ABATING TREND ON MONDAY WILL BE
GRADUAL DUE TO THE SLOW MOVEMENT OF THE SYSTEM. WINDS DROP OFF
MORE SUBSTANTIALLY MONDAY NIGHT AS IT GETS CAUGHT BACK UP IN THE
JET AND ACCELERATES EASTWARD. FLAGS WILL BE ABLE TO BE DROPPED
SOME TIME LATE MONDAY. TUESDAY BRINGS LIGHT WINDS THAT WILL BE
BACKING AND THERE WILL STILL BE A LITTLE BACKSWELL FROM THE SYSTEM
AS IT CONTINUES TO MOVE EAST OUT TO SEA.

&&

.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 PM EDT FRIDAY FOR AMZ250-252-254-
     256.

&&

$$

SYNOPSIS...REK
NEAR TERM...CRM
SHORT TERM...REK
LONG TERM...MBB
AVIATION...MRR
MARINE...REK/MBB/CRM




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