National Weather Service United States Department of Commerce

 


000
FXUS62 KILM 241949
AFDILM

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WILMINGTON NC
349 PM EDT THU APR 24 2014

.SYNOPSIS...
DRY HIGH PRESSURE ACROSS THE AREA WILL MOVE OFFSHORE TONIGHT.
WARMER AND MORE HUMID CONDITIONS ARE EXPECTED FRIDAY...WITH A
CHANCE OF SHOWERS AND THUNDERSTORMS AHEAD OF A COLD FRONT. HIGH
PRESSURE WILL BRING SUNSHINE AND ABOVE NORMAL TEMPERATURES DURING
THE WEEKEND. UNSETTLED WEATHER IS EXPECTED BY THE MIDDLE OF NEXT
WEEK...AS A STRONG UPPER LOW DRIVES A SLOW MOVING STORM SYSTEM
ACROSS THE COUNTRY.

&&

.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
AS OF 330 PM THURSDAY...FAIR AND PLEASANT WEATHER CONDITIONS WILL
PREVAIL INTO THE EVENING HOURS...AS DRY AIR ASSOCIATED WITH A GULF
COAST UPPER RIDGE DRIFTS EASTWARD ACROSS THE CAROLINAS.

INCREASING LOW-LEVEL CLOUDS AND SOUTHERLY WINDS LATE TONIGHT AHEAD
OF AN APPROACHING FRONTAL SYSTEM MAY LEAD TO A-TYPICAL HOURLY
TEMPERATURE CURVES LATE TONIGHT...WITH MINIMUM TEMPERATURES BEING
REALIZED PRIOR TO DAYBREAK OVER MANY LOCATIONS...AS CLOUDS AND
MIXING IMPACT RADIATIONAL NIGHT-TIME COOLING TRENDS AFTER 6Z.

WILL STILL HOLD ONTO A SLIGHT CHANCE OF SHOWERS ALONG OUR COAST
BETWEEN 9Z-12Z/5AM-8AM...TO ACCOUNT FOR A FEW SHOWERS WHICH MAY
SPRING FROM LOW-LEVEL CONVERGENCE. TIME-HEIGHT ANALYSIS SHOWS THE
SHOWERS WOULD BE LOW-TOPPED...WHILE STEERING WINDS GUIDE THEM SSW
TO NNE...POTENTIALLY CLIPPING OUR COASTAL STRIPS AND THE CAPE FEAR
REGION AN HOUR OR 2 EITHER SIDE OF SUN-UP.

MINIMUM TEMPS TO SHOW A WIDE RANGE FROM THE LOWER 50S ACROSS OUR
NORTHERN INTERIOR SE NC ZONES...TO THE MIDDLE AND UPPER 50S OVER
THE REMAINDER OF OUR INLAND SITES...AND AROUND 60 TO THE LOWER 60S
ALONG OUR IMMEDIATE COAST AND BEACHES. SSTS HAVE WARMED A FEW
DEGREE THE LAST FEW DAYS AND NOW MAINLY LOWER 60S INSHORE.

&&

.SHORT TERM /6 AM FRIDAY MORNING THROUGH SATURDAY NIGHT/...
AS OF 330 PM THURSDAY...FRIDAY CONTINUES TO BE HIGHLIGHTED BY SPC
IN THE SWODY2 WITH A "SLIGHT RISK" FOR POSSIBLE SEVERE
STORMS...PRIMARILY ALONG OUR IMMEDIATE NORTHERN COUNTIES.
HOWEVER...THE THREAT CONTINUES TO LOOK RATHER MINIMAL LOCALLY. A
DE-AMPLIFYING UPPER TROUGH WILL MOVE NORTH OF THE AREA ON
FRIDAY...CROSSING INTO NEW ENGLAND BY FRIDAY NIGHT. A SURFACE LOW
BENEATH THIS FEATURE WILL ALSO MOVE NORTH OF THE AREA DURING
FRIDAY AFTN...DRAGGING A WEAK COLD FRONT THROUGH THE CAROLINAS BY
FRIDAY NIGHT. AHEAD OF THIS FRONT...CONVECTION WILL BE POSSIBLE AS
STRONG DIURNAL HEATING...TEMPS RISING TO AROUND 80...DRIVES
SURFACE INSTABILITY OF 600-1000 J/KG...INTO AN ENVIRONMENT
CHARACTERIZED BY STRONG THETA-E RIDGING DRIVEN BY A 30 KT
SOUTHERLY LLJ.

NORMALLY...THIS LEVEL OF INSTABILITY COMBINED WITH A MID-LEVEL
IMPULSE AND THIS AMOUNT OF MOISTURE WOULD PROVIDE A GOOD ENVIRONMENT
FOR CONVECTION...POSSIBLY STRONG.

HOWEVER...IT APPEARS THE MID-LEVEL TROUGH WILL MOVE AHEAD OF THE
SURFACE FEATURE...AND DRYING COMBINED WITH POSITIVE THICKNESS
ADVECTION WILL OCCUR THROUGH THE AFTN. THIS WILL WEAKEN MID-
LEVEL LAPSE RATES AND PUT ON A LID ON ANY POTENTIAL STRONG
CONVECTION. THUS...CANNOT RULE OUT AN ISOLATED STRONG UPDRAFT WITH
SOME HAIL OR A STRONG WIND GUST...BUT PEAK HEATING WILL NOT
CORRELATE WELL WITH BEST DYNAMICS ON FRIDAY...AND THUS THINK THE
SEVERE THREAT IS QUITE LOW. IN FACT...WITH THE BEST DYNAMICS GOING
NORTH OF THE AREA...AND MOISTURE ADVECTION HAVING ONLY A SHORT
DURATION AHEAD OF THE BOUNDARY...THE SC COUNTIES MAY NOT SEE MUCH
PRECIP AT ALL ON FRIDAY. HIGHEST POP WILL BE LATE MORNING/EARLY
AFTN...FALLING OFF TO SILENT BY NIGHT. MINS FRIDAY NIGHT WILL
REMAIN ABOVE CLIMO AS THE FRONT CROSSES LATE...AND WITH ONLY WEAK
CAA. EXPECT LOWS AROUND 60 AT THE COAST...MID 50S WELL INLAND.

BEAUTIFUL SPRING WEATHER RETURNS TO THE AREA ON SATURDAY. 5H PATTERN
BEGINS TO TREND TOWARDS ONE OF HIGH AMPLIFICATION...WITH DOWNSTREAM
RIDGING ACROSS THE CAROLINAS BULGING 5H HEIGHTS TOWARDS 580DM DURING
THE WKND. THIS WILL MAKE SATURDAY A WARM AND SUNNY DAY...WITH HIGHS
IN THE LOW 80S...NEAR 80 AT THE COAST. LOWS SATURDAY NIGHT WILL DROP
INTO THE UPPER 50S.

&&

.LONG TERM /SUNDAY THROUGH THURSDAY/...
AS OF 330 PM THURSDAY...THE EXTENDED FORECAST REMAINS ESSENTIALLY
UNCHANGED FROM THE PREVIOUS PACKAGE. THE TIMING AND STRENGTH OF
THE COLD FRONT ASSOCIATED WITH A PLODDING MID LEVEL LOW EJECTING
FROM THE SOUTHWEST AND MOVING ACROSS THE MISSISSIPPI VALLEY
REMAINS THE FOCUS. WE CONTINUE TO ADVERTISE CHANCE POPS FOR
TUESDAY AND WEDNESDAY AS THE BEST MOISTURE AND LIFT ARE COUPLED
HERE.

THE MID LEVEL LOW REMAINS IN PLACE OR MAY RETROGRADE SLIGHTLY INTO
THE CENTRAL PLAINS AS DRY AIR IS WRAPPED IN FROM THE SOUTHWEST. WITH
THE MODELS CONSISTENCY IN SHOWING THIS FEATURE...WE COULD SEE
SEVERAL SURFACE BOUNDARIES MOVE ACROSS SLOWLY ENHANCING THE RAINFALL
POTENTIAL. ITS WORTH NOTING WPC HAS IN EXCESS OF THREE INCHES IN
PLACES FOR THE SEVEN DAY QPF. IF THIS COMES TO FRUITION...IT COULD
BECOME ONE OF THE WETTEST APRILS AT LEAST IN WILMINGTON HISTORY.

&&

.AVIATION /20Z THURSDAY THROUGH TUESDAY/...
AS OF 18Z...HIGH PRESSURE WILL BE IN CONTROL FOR THE NEXT 12
HOURS OR SO...IT THEN WILL PUSH OFF TO THE EAST AS LOW PRESSURE
APPROACHES. MAINLY SOUTHEAST WINDS ALONG THE COAST THIS AFTERNOON
WITH THE SEA BREEZE. TONIGHT...RETURN FLOW IS EXPECTED ALONG THE
COAST WITH A POSSIBLE MVFR CEILING ALTHOUGH CONFIDENCE IS RATHER LOW
AT THIS POINT. THE NAM IS HINTING A SOME SCATTERED LIGHT SHOWERS
NEAR THE COAST WITH A WEAK CONVERGENT BOUNDARY.

FRIDAY...MODERATELY POTENT VORT MAX ROTATES THROUGH THE NORTHERN
PORTION OF THE CWA. THERE WILL BE SHOWERS AROUND...LOW CERTAINTY
WITH RESPECT TO COVERAGE. MOST OF THE CONVECTION WILL BE LOW TOPPED
DUE TO LACK OF MOISTURE IN THE MID LEVELS. A RUMBLE OF THUNDER IS
NOT IMPOSSIBLE...JUST UNLIKELY. SOUTH WINDS WILL INCREASE JUST AHEAD
OF THE PRECIPITATION.

EXTENDED OUTLOOK...VFR SATURDAY AND SUNDAY. MORNING FOG POSSIBLE
MONDAY. SHOWERS POSSIBLE TUESDAY.

&&

.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 330 PM THURSDAY...NO SIGNIFICANT HAZARDS ON THE
WATERS...BUT WE WILL SEE AN INCREASE IN SE-S WINDS OVERNIGHT AS A
COLD FRONT APPROACHES THE COAST FROM THE WEST...WITH NO ADVISORIES
PLANNED AS SEAS HOLD AT 3-4 FEET MUCH OF THE NIGHT. WEAK SWELL IN
SE WAVES AROUND 1 FOOT EVERY 8-9 SECONDS WILL CO-MINGLE WITH
GROWING SE-S CHOP LATE TONIGHT INTO EARLY FRIDAY. ISOLATED SHOWERS
OVER THE WATERS CAN BE EXPECTED AROUND DAYBREAK...BUT TSTMS NOT
EXPECTED NEAR SHORE THROUGH 8AM FRIDAY.

SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
AS OF 330 PM THURSDAY...HIGH PRESSURE OFFSHORE AND A COLD FRONT
APPROACHING FROM THE WEST CREATE A PINCHED GRADIENT AND INCREASING
SOUTHERLY WINDS ON FRIDAY. WINDS WILL RISE TO 15-20 KTS FRIDAY
AFTN/EVE...AND THEN SHIFT TO THE NW FRIDAY NIGHT AT AROUND 15 KTS
BEHIND THE COLD FRONT. HIGH PRESSURE WILL THEN AGAIN BUILD ACROSS
THE WATERS SATURDAY...WITH WINDS FALLING TO AROUND 10 KTS AND
BACKING SLOWLY FROM NW TO SW THROUGH THE DAY. SEAS WILL BE HIGHEST
IMMEDIATELY AHEAD OF THE COLD FRONT...AS THE WINDS DRIVE WAVE
HEIGHTS UP TO 3-5 FT. THESE WILL FALL QUICKLY ON SATURDAY AS THE NW
WIND PUSHES HIGHEST SEAS OFFSHORE IN CONJUNCTION WITH THE EASING
SPEEDS...AND WAVE HEIGHTS OF 1-2 FT ARE ANTICIPATED SATURDAY.

LONG TERM /SUNDAY THROUGH TUESDAY/...
AS OF 330 PM THURSDAY...RELATIVELY LIGHT WINDS FOR SUNDAY AND
MONDAY AS A WEAK BOUNDARY WILL BE IN THE PROCESS OF DISSIPATING AS
A STRONGER SYSTEM DEVELOPS WELL TO THE WEST. EXPECT A SOUTH TO
SOUTHEASTERLY FLOW OF AROUND TEN KNOTS OR LESS. WINDS WILL
INCREASE TO 15-20 KNOTS TUESDAY AS THE SYSTEM MOVES CLOSER FROM
THE WEST. SIGNIFICANT SEAS INCREASE FROM A VERY MARGINAL 1-3 FEET
EARLY TO 3-5 FEET LATE WITH THE INCREASE IN WINDS.

&&

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

&&

$$
SYNOPSIS...JDW
NEAR TERM...MJC
SHORT TERM...JDW
LONG TERM...SHK
AVIATION...MJC/DL
MARINE...MJC/JDW/SHK