Area Forecast Discussion
Issued by NWS Wilmington, NC

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000
FXUS62 KILM 290704
AFDILM

AREA FORECAST DISCUSSION...COR
NATIONAL WEATHER SERVICE WILMINGTON NC
300 AM EDT WED JUL 29 2015

.SYNOPSIS...
HIGH PRESSURE WILL SLOWLY WEAKEN THROUGH MID WEEK. A PIEDMONT TROUGH
WILL FORM THIS AFTERNOON AND LINGER ON THURSDAY AS WEAK LOW
PRESSURE REMAINS OFF THE SOUTHEAST COAST. A COLD FRONT WILL MOVE
INTO THE AREA FRIDAY AND STALL DURING THE WEEKEND BEFORE FINALLY
DISSIPATING ON MONDAY.

&&

.NEAR TERM /THROUGH TONIGHT/...
AS OF 3 AM WEDNESDAY...VAPOR ANIMATIONS SHOW A DRY INTRUSION ALOFT
PUSHING SOUTHWARD ACROSS THE MID-ATLANTIC INTO THE CAROLINAS EARLY
THIS MORNING. TIME-HEIGHT ANALYSIS OF RH AND WIND TRAJECTORIES SHOW
THIS DRY AIR EMBEDDED BETWEEN H5-H3 IN A 25-35 KT NORTH WIND FLOW.
THIS ADVECTION WILL CAP LOCAL CHANCES OF PRECIPITATION FOR MOST
AREAS TODAY. THE EXCEPTION AREA RESIDES MAINLY WEST OF I-95 WHERE
THE STRONGEST LOW-LEVEL HEATING WILL OCCUR...AND CLOSEST IN
PROXIMITY TO DYING DISTURBANCES ALOFT APPROACHING FROM THE NNW BUT
EVEN THIS IS UNCERTAIN. MAXIMUMS TODAY 91-94 INLAND...AROUND 90
COASTAL INTERIOR AND UPPER 80S BEACHES AND ICW CORRIDOR. DIURNAL
COOLING WILL KILL WHAT FEW SHOWERS CROP UP LATER THIS AFTERNOON IN
THE EARLY EVENING WITH A DRY LAYER ALOFT COVERING THE AREA. MINIMUM
TEMPERATURES AT DAYBREAK THURSDAY LOW TO MID 70S INLAND AND UPPER
70S COAST.

&&

.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 3 AM WEDNESDAY...PRECIP CHANCES WILL BE ON THE INCREASE
DURING THE PERIOD AS 5H RIDGE BREAKS DOWN AND 5H TROUGH STARTS TO
SET UP. ILL DEFINED SURFACE PATTERN ON THU WILL ALLOW SEA BREEZE
AND PIEDMONT TROUGH CONVECTION BUT LACK OF SIGNIFICANT SURFACE OR
MID LEVEL TRIGGERS WILL KEEP COVERAGE LIMITED. PRECIP CHANCES
START TO INCREASE THU NIGHT AS WEAKENING COLD FRONT MOVES IN FROM
THE NORTHWEST. FRONT ARRIVES AS INSTABILITY IS WANING WHICH SHOULD
KEEP COVERAGE FOR THU NIGHT IN SLIGHT CHC RANGE AT MOST DESPITE
THE PRESENCE OF LOW LEVEL CONVERGENCE AND DEEP MOISTURE.

FRONT REMAINS IN THE AREA FRI...SERVING AS A FOCAL POINT FOR
CONVECTION. DIURNAL INSTABILITY WILL HAVE PLENTY OF DEEP MOISTURE TO
WORK WITH...PRECIPITABLE WATERS EXCEED 2 INCHES LATER IN THE DAY.
WEAKENING SUBSIDENCE AND INSTABILITY ALONG WITH WHAT APPEARS TO BE
SOME SLIGHT PVA FRI AFTERNOON INCREASES PRECIP CHANCES FRI INTO FRI
NIGHT. WILL CONTINUE WITH INHERITED LIKELY POP BUT WONDER IF MID
LEVEL RIDGING MIGHT HOLD ON A BIT LONGER THAN GUIDANCE IS
SUGGESTING. SHOULD THAT BE THE CASE LINGERING SUBSIDENCE COULD KEEP
CONVECTION IN CHECK...RESULTING IN SLIGHTLY LOWER POP THAN WHAT
IS CURRENTLY FORECAST FOR THE SECOND HALF OF THE PERIOD.

&&

.LONG TERM /SATURDAY THROUGH TUESDAY/...
AS OF 3 AM WEDNESDAY...STALLED FRONT AND DEEP MOISTURE LINGERS OVER
THE AREA SAT KEEPING WEATHER UNSETTLED THROUGH THE WEEKS END. AT
THIS POINT UNCERTAINTY IN THE FORECAST REALLY STARTS TO INCREASE.
BOTH GFS AND ECMWF SHOW A 5H TROUGH DIGGING DOWN THE EAST COAST. MID
LEVEL TROUGH PUSHES THE DEEP MOISTURE OFF THE COAST FOR THE START OF
NEXT WEEK WITH THE REGION DRYING OUT. SURFACE PATTERN REMAINS ILL
DEFINED AND WHATS LEFT OF THE SURFACE BOUNDARY WILL LINGER IN THE
AREA. HOWEVER THE LACK OF DEEP MOISTURE KEEPS PRECIP CHANCES AT OR
BELOW THE TYPICAL SUMMERTIME AFTERNOON 30 POP TO START THE WEEK.

PREVIOUSLY GUIDANCE HAD BEEN SHOWING A STRONGER SHORTWAVE DROPPING
ACROSS THE AREA IN THE DEEP NORTHWEST FLOW TUE. WHILE THIS FEATURE
IS STILL DISCERNIBLE...JUST BARELY...IT IS IN A WEAKER STATE. AS
THESE SHORTWAVES ARE FREQUENTLY CONVECTIVELY INDUCED/INFLUENCED WILL
NOT GO ABOVE CLIMO POP FOR THE END OF THE PERIOD GIVEN THE
HEIGHTENED UNCERTAINTY. TEMPERATURES WILL BE NEAR TO SLIGHTLY ABOVE
CLIMO...GENERALLY NEAR CLIMO BY DAY AND SLIGHTLY ABOVE BY NIGHT.

&&

.AVIATION /07Z WEDNESDAY THROUGH SUNDAY/...
AS OF 06Z...LITTLE CHANGE IN THE OVERALL PATTERN IS EXPECTED THIS
TAF VALID PERIOD WITH HIGH PRESSURE N OF THE TERMINALS AND A LOW
PRESSURE TROUGH OFFSHORE. WINDS WILL BE LIGHT NE-E...EXCEPT E-SE
6-12 KT AFTER SUNRISE INTO EARLY EVENING. SCT CU/SC 2-4K EXPECTED
THROUGH THE PERIOD DUE TO A PERSISTENT LOW LEVEL ONSHORE FLOW.

THERE IS A CONTINUED CHANCE OF FOG DEVELOPMENT EARLY THIS MORNING
AS CLOUDS SCATTER. WILL INDICATE TEMPO MVFR VSBYS ATTM AT KFLO/KLBT
BUT CONFIDENCE IS LOW SINCE THIS SAME PATTERN HAS YET TO YIELD FOG
THE PAST SEVERAL MORNINGS. BUT THERE IS INCREASING CONFIDENCE OF
LOW MVFR OR IFR CIGS DEVELOPING BY 10Z AT THE COASTAL TERMINALS.
BEST CONFIDENCE OF ANY IFR WOULD BE AT KMYR. SOME SHOWERS MAY DEVELOP
IN THE AFTERNOON BETWEEN THE INLAND AND COASTAL TERMINALS.

EXTENDED OUTLOOK...PREDOMINANTLY VFR THROUGH THE PERIOD WITH A
SLIGHT CHANCE AFTERNOON SHRA/TSRA. BEST CHANCE SHRA/TSRA FRIDAY AND
SATURDAY.

&&

.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 3 AM WEDNESDAY...E WIND 10-15 KT TO PREVAIL TODAY AND
TONIGHT...ACCOMPANIED BY 3-3.5 FOOT SEAS. SEAS PRIMARILY A MIX OF
SE WAVES 2-3 FT EVERY 6 SECONDS AND MODERATELY EASTERLY CHOP.
SHOWERS AND TSTMS ARE EXPECTED TO REMAIN WELL BEYOND THE 0-20 NM
WATERS TODAY AND NO RESTRICTIONS TO VISIBILITY ARE EXPECTED.

SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 3 AM WEDNESDAY...ILL-DEFINED GRADIENT AND WEAK SURFACE WAVE
PASSING EAST OF THE WATERS THU WILL INDUCE LIGHT NORTH TO
NORTHEAST FLOW INTO THU NIGHT. WAVE MOVES OFF TO THE NORTHEAST THU
NIGHT INTO FRI AS WEAK SURFACE FRONT DROPS IN FROM THE NORTHWEST.
LIGHT AND VARIABLE WINDS THU NIGHT GAIN A SOUTHWEST COMPONENT FRI
AND FRI NIGHT BUT LACK OF ANY REAL GRADIENT KEEPS SPEEDS AROUND 10
KT THROUGH THE END OF THE PERIOD. SEAS 2 TO 3 FT THROUGH THE
PERIOD.


LONG TERM /SATURDAY THROUGH SUNDAY/...
AS OF 3 AM WEDNESDAY...SOUTHWEST FLOW WILL CONTINUE OVER THE
WATERS THROUGH THE WEEKEND. THE REMAINS OF A STALLED FRONT WILL
LINGER NEAR THE COAST AS BERMUDA HIGH TRIES TO BUILD BACK WEST.
GRADIENT WILL REMAIN ON THE WEAK SIDE WITH SPEEDS NO MORE THAN 10
TO 15 KT AT ANY POINT DURING THE PERIOD. DAILY SEA BREEZE WILL
RESULT IN ENHANCED ONSHORE FLOW NEAR THE COAST BOTH DAYS. SEAS
WILL RUN 2 TO 3 FT ON SAT AND 2 TO 4 FT SUN.

&&

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

&&

$$

NEAR TERM...8
SHORT TERM...III
LONG TERM...III
AVIATION...MRR/8


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