660 
FXUS62 KILM 281054
AFDILM

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WILMINGTON NC
654 AM EDT FRI MAR 28 2014

.SYNOPSIS...
MUCH MORE MOIST AND WARMER AIR WILL BE IN PLACE AHEAD OF A COLD 
FRONT APPROACHING FROM THE WEST. THE FRONT WILL MOVE ACROSS THE AREA 
SATURDAY NIGHT. THE RISK FOR SHOWERS AND THUNDERSTORMS WILL BE ON 
THE INCREASE UNTIL PASSAGE OF THE COLD FRONT. SOME STORMS MAY BE 
STRONG TO SEVERE SATURDAY AND SATURDAY NIGHT. A BRIEF COOL DOWN WILL 
OCCUR BEHIND THE FRONT SUNDAY. HIGH PRESSURE NEXT WEEK WILL BRING 
DRY WEATHER WITH TEMPERATURES CLIMBING WELL ABOVE NORMAL. A COLD 
FRONT MAY REACH THE AREA NEXT FRIDAY...BRINGING A RISK FOR SHOWERS.

&&

.NEAR TERM /THROUGH TONIGHT/...
AS OF 600 AM FRIDAY...RETURN FLOW AROUND DEPARTING HIGH PRESSURE HAS 
TAKEN A FIRM HOLD ON THE AREA AND WE ARE BEGINNING TO SEE DEWPOINTS 
SURGE HIGHER...NOW UP TO THE MID AND UPPER 40S ALONG THE COAST...AND 
IN THE LOWER 40S FOR MOST INLAND LOCATIONS. TEMPS HAVE ALSO RISEN 
WITH THE APPROACH OF MORNING...IN THE MID AND UPPER 40S IN MOST 
LOCATIONS...TOPPING 50 DEGREES IN SOME COASTAL AREAS.

DEEP S TO SW FLOW WILL BE IN PLACE THIS PERIOD AND THIS WILL BRING 
INCREASING MOISTURE AND TEMPERATURE WHICH WILL RESULT IN INCREASED 
INSTABILITY. PRECIPITABLE WATER VALUES WILL BE NEAR 1 INCH THIS 
MORNING...CLIMBING TO 1.25 TO 1.5 INCHES LATER TODAY AND TONIGHT. 
THE COLUMN SUFFICIENTLY SATURATES TO A DEPTH THAT DOES SUPPORT 
MEASURABLE PRECIPITATION. SHORTWAVE ENERGY IN THE MID LEVELS DOES 
APPROACH FROM THE W TODAY AND THEN ACROSS THE AREA TONIGHT. THERE IS 
SOME INDICATION THE ENERGY MAY SPLIT...WITH THE FORECAST AREA LYING 
IN BETWEEN THE BEST UPPER LEVEL SUPPORT. THERE IS ALSO SOME CONCERN 
THAT WIDESPREAD CONVECTION ALONG THE GULF COAST MAY SERVE TO ROB OR 
AT LEAST DELAY DEEPER MOISTURE RETURN. 

AN EXAMINATION OF INSTABILITY AND MID LEVEL LAPSE RATES DOES SUPPORT 
INCLUSION OF HIGHER POPS THIS PERIOD. MIXED LAYER CAPE VALUES DO 
CLIMB TO 300 J/KG WHILE SURFACE BASED VALUES REACH 500 TO 1000 J/KG. 
MID LEVEL LAPSE RATES DO REACH UP TO 7 DEG C/KM.

SO ALTHOUGH WE ARE CONFIDENT MEASURABLE PRECIPITATION WILL OCCUR...
THERE IS SOME UNCERTAINTY AS TO WHEN TO INCLUDE THE HIGHEST POPS. 
LOOKING AT THE MOST RECENT RADAR/SATELLITE DATA...THERE IS A LARGE 
AREA OF DEEP CONVECTION ONGOING ACROSS THE CENTRAL AND EASTERN GULF 
COASTAL AREAS. THIS SUGGESTS DEEPEST MOISTURE RETURN MAY BE DELAYED. 
EXTRAPOLATION FOR TIMING WOULD BRING THE HIGHEST RISK FOR SHOWERS 
AND THUNDERSTORMS INTO THE AREA TONIGHT...MORE LIKELY LATE TONIGHT 
WITH THE ARRIVAL OF AN UPPER LEVEL IMPULSE WORKING ITS WAY UP THE 
CAROLINA COAST. OF COURSE THIS DOES NOT PRECLUDE SHOWERS AND SOME 
THUNDERSTORMS TODAY OR THIS EVE AND HIGHER RESOLUTION MODELS ARE 
SHOWING CONVECTION BREAKING OUT WITH HEATING OF THE DAY WITH PERHAPS 
THE SEA BREEZE SERVING AS A FOCAL POINT. RAINFALL AMOUNTS WILL BE 
HIGHLY VARIABLE...BUT SOME LOCATIONS COULD RECEIVE AS MUCH AS 
THREE-QUARTERS OF AN INCH WITH ONE-QUARTER TO ONE-HALF INCH MORE 
COMMON...THESE AMOUNTS JUST THROUGH TONIGHT.

THICKER CLOUD COVER WILL BE ARRIVING/DEVELOPING THROUGH THE DAY WITH 
MORE OR LESS CLOUDY SKIES EXPECTED DURING THE AFTERNOON AND TONIGHT. 
ALSO...AS DEWPOINTS CREEP HIGHER...WE SHOULD BEGIN TO SEE SEA 
STRATUS/SEA FOG DEVELOP...PERHAPS IMPINGING ONTO THE IMMEDIATE COAST 
IN SOUTHERLY FLOW LATE DAY AND ESPECIALLY TONIGHT.

HIGH TEMPS WILL BE IN THE LOWER TO MID 70S TODAY...BUT THE SEABREEZE 
WILL KEEP COASTAL AREAS IN THE MID AND UPPER 60S. LOWS TONIGHT WILL 
BE BALMY AS COMPARED TO RECENT NIGHTS...UPPER 50S TO AROUND 60 
DEGREES.

&&

.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
AS OF 300 AM FRIDAY...SURFACE LOW AND MID LEVEL TROUGH WILL BE WEST 
OF THE AREA AT THE START OF THE PERIOD WITH THE REGION SOLIDLY IN 
THE WARM SECTOR. SEVERAL FACTORS APPEAR TO BE IN PLACE SUPPORTING 
CONVECTION SAT INTO SAT NIGHT. STRENGTHENING MID LEVEL SOUTHWEST 
FLOW WILL CONTINUE TO PUMP MOISTURE INTO THE REGION. FORECAST 
SOUNDINGS SHOW PRECIPITABLE WATER VALUES CLOSE TO 1.5 INCH. DIURNAL 
INSTABILITY WILL ALSO BE PRESENT WITH HIGHS EXPECTED TO CLIMB INTO 
THE LOWER 70S IN MOST AREAS. LOW LEVEL CONVERGENCE ALONG THE 
RESULTANT SEA BREEZE MAY INITIATE CONVECTION IN THE AFTERNOON. ALOFT 
THE APPROACHING 5H TROUGH WILL ENHANCE MID LEVEL LAPSE RATES BUT THE 
UNKNOWN FACTOR AT THIS POINT REMAINS WHAT IMPACT POTENTIAL 
CONVECTION IN THE NORTHEAST GULF OF MEXICO WILL HAVE ON INSTABILITY 
SHOWERS/THUNDERSTORMS.

FARTHER WEST A LINE OF CONVECTION SHOULD BE DEVELOPING ASSOCIATED 
WITH THE ADVANCING COLD FRONT. THIS LINE WILL MOVE INTO WHAT SHOULD 
BE A MOIST/UNSTABLE ENVIRONMENT LATE SAT AND PUSH OFF THE COAST SAT 
NIGHT. ALTHOUGH THE FRONT WILL HAVE PLENTY OF LOW LEVEL CONVERGENCE 
AND MID LEVEL SUPPORT THERE IS SOME QUESTION AS TO THE STATE OF THE 
ATMOSPHERE IT WILL BE MOVING INTO. THE CONVECTIVE LINE ASSOCIATED 
WITH THE FRONT MAY END UP WEAKENING AS IT MOVES INTO THE REGION IF 
EARLIER AFTERNOON CONVECTION IS MORE WIDESPREAD AND USES UP A LOT OF 
THE AVAILABLE INSTABILITY. ON THE OTHER HAND SHOULD THE GULF 
CONVECTION BE ABLE TO SUPPRESS MUCH OF THE ACTIVITY DURING THE FIRST 
HALF OF SAT THE COLD FRONT WOULD HAVE PLENTY OF INSTABILITY TO WORK 
WITH. SO IT IS NOT SO MUCH A QUESTION OF WILL IT RAIN...BUT MORE OF 
A QUESTION OF WHEN WILL IT RAIN. 

SEVERE WEATHER THREAT PERSISTS...ALTHOUGH WITH CAVEATS. LOW LEVEL 
JETTING WILL BE WEAK FOR MUCH OF THE DAY BEFORE INCREASING TO 30 TO 
35 KT JUST AHEAD OF THE FRONT. THE MAIN THREAT WOULD BE DAMAGING 
WIND...ENHANCED BY STORMS MOVING CLOSE TO 30 MPH. IF STRONG/SEVERE 
STORMS DEVELOP THEY ARE LIKELY TO DO SO WITH THE LINE OF CONVECTION 
AHEAD OF THE FRONT...AGAIN ASSUMING DIURNAL DRIVEN CONVECTION IS 
LIMITED IN SCOPE DURING THE DAY SAT.

COLD FRONT PUSHES OFF THE COAST LATE SAT NIGHT WITH THE MID LEVEL 
TROUGH FOLLOWING ON SUN. COLD ADVECTION BEHIND THE FRONT WILL DROP 
SUN TEMPS BELOW CLIMO...BUT COLD AIR WILL BE A LITTLE TOO LATE TO 
HAVE A SIGNIFICANT IMPACT ON SAT NIGHT LOWS WHICH WILL END UP NEAR 
TO SLIGHTLY ABOVE CLIMO. SUN SHOULD BE DRY WITH DEEP NORTHWEST FLOW 
BEHIND THE TROUGH DROPPING PWATS UNDER .5 INCH FOR SUN AM AND UNDER 
.25 INCH BY SUN EVENING. GRADIENT RELAXES SUN NIGHT BUT HIGH REMAINS 
WEST OF THE AREA THROUGH THE END OF THE PERIOD SO SUN NIGHT WILL NOT 
BE AN IDEAL RADIATIONAL COOLING NIGHT. STILL LOWS END UP BELOW CLIMO.

&&

.LONG TERM /MONDAY THROUGH THURSDAY/...
AS OF 300 AM FRIDAY...LOW AMPLITUDE MID LEVEL RIDGING AND SPRAWLING 
SURFACE HIGH WILL KEEP THE AREA DRY AND SEASONABLE THROUGH THE 
PERIOD. COOLEST DAY WILL BE MON WITH SURFACE HIGH DIRECTLY OVERHEAD. 
HIGH THEN DRIFTS OFFSHORE TUE THROUGH THU BRINGING SEVERAL DAYS OF 
BEAUTIFUL SPRING WEATHER. PREVIOUSLY MEDIUM RANGE GUIDANCE HAD BEEN 
MOVING A DRY COLD FRONT ACROSS THE AREA TUE NIGHT INTO WED. NOW THAT 
GUIDANCE IS SUGGESTING MORE MID LEVEL AMPLIFICATION THIS SEEMS 
UNLIKELY AND IN FACT THE 00Z GUIDANCE IS BACKING OFF ON THE DRY 
FRONT. TEMPERATURES NEAR TO SLIGHTLY ABOVE CLIMO MON TRANSITION TO 
ABOVE CLIMO MON NIGHT THROUGH THE END OF THE PERIOD. 

&&

.AVIATION /12Z FRIDAY THROUGH TUESDAY/...
AS OF 12Z...RETURN FLOW WILL COMMENCE SHORTLY. HAVE LEANED FAIRLY 
HEAVILY ON THE HRRR EARLY...WITH SHOWERS POPPING UP ALONG THE 
MYRTLES BY LATE MORNING. INCREASING SOUTHERLY GRADIENT WILL CAUSE 
WINDS TO GUSTS OVER 20 KTS AT TIMES...ESPECIALLY ALONG THE COAST. 
SCATTERED SHOWERS WILL GIVE WAY TO MORE WIDESPREAD RAIN THIS EVENING 
AS DEEP MOISTURE MOVES INTO THE REGION. RAIN CHANCES WILL BE HIGHEST 
INLAND THIS EVENING...SPREADING TO THE COAST A FEW HOURS LATER. 
CEILINGS ARE A BIT PROBLEMATIC...BUT WILL GO FOR MVFR PREDOMINATELY 
WITH POCKETS OF IFR POSSIBLE.

EXTENDED OUTLOOK...SHOWERS AND T-STORMS WITH MVFR/TEMPO IFR 
CONDITIONS OVERNIGHT AND ON SATURDAY. VFR SUNDAY THROUGH TUESDAY.

&&

.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 600 AM FRIDAY...THE PRESSURE GRADIENT BETWEEN A LARGE AREA OF
HIGH PRESSURE OFFSHORE AND A TROUGH OF LOW PRESSURE TO OUR W WILL
BE TIGHTEST TONIGHT...ESPECIALLY LATE TONIGHT AND SAT AS THE
TROUGH BEGINS TO MAKE ITS EASTWARD PUSH. THUS THIS IS WHEN THE
STRONGEST WINDS ARE EXPECTED ACROSS THE WATERS. THE STRONGEST
WINDS ARE EXPECTED ACROSS THE OUTERMOST WATERS AND EASTWARD WHERE
SEA SURFACE TEMPS ARE MUCH HIGHER THAN ACROSS THE NEAR SHORE
WATERS...THUS ALLOWING FOR THE GREATEST MIXING. WIND SPEEDS WITHIN
20 NM OF THE COAST WILL BE AS HIGH AS 15 TO 20 KT. PERSISTENTLY
HIGHER SOUTH WINDS OFFSHORE WILL ALLOW SEAS TO BUILD AND EXPECT
THE 6 FT THRESHOLD WILL BE MET ACROSS PORTIONS OF THE OUTER WATERS
AS EARLY AS THIS AFTERNOON AND MORESO TONIGHT...NECESSITATING A
SMALL CRAFT ADVISORY WHICH WILL BE RAISED AT THIS TIME.
FINALLY...HIGHER DEWPOINTS ADVECTING NORTHWARD AHEAD OF AN
APPROACHING TROUGH SHOULD ALLOW FOR THE DEVELOPMENT OF SEA
FOG...LIKELY MOST PREVALENT OVERNIGHT.

SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
AS OF 300 AM FRIDAY...SOUTHERLY FLOW WILL APPROACH 20 KT SAT AS 
GRADIENT OVER THE WATERS IS PINCHED BETWEEN ADVANCING COLD FRONT AND 
HIGH PRESSURE. ANTICIPATE A LINE OF CONVECTION AHEAD OF THE FRONT 
WHICH WILL CROSS THE WATERS SAT EVE/NIGHT. OFFSHORE FLOW DEVELOPS 
BEHIND THE FRONT WITH GRADIENT AND DEVELOPING COLD ADVECTION KEEPING 
SPEEDS AROUND 20 KT. LITTLE CHANGE IN THE GRADIENT SUN AS HIGH 
BUILDS KEEPS NORTHWEST WINDS A SOLID 20 KT FOR MUCH OF THE DAY. 
OFFSHORE FLOW SLOWLY WEAKENS SUN NIGHT...DROPPING TO 15 KT BY THE 
END OF THE PERIOD...AS GRADIENT RELAXES. SEAS 4 TO 6 FT EXPECTED SAT 
INTO SUN WHEN OFFSHORE COMPONENT DROPS SEAS TO 3 TO 5 FT. CONTINUED 
OFFSHORE FLOW COMBINED WITH REDUCTION IN SPEEDS SUN NIGHT WILL DROP 
SEAS TO 2 TO 4 FT BY THE END OF THE PERIOD.

LONG TERM /MONDAY THROUGH TUESDAY/...
AS OF 300 AM FRIDAY...OFFSHORE FLOW AROUND 15 KT AT THE START OF THE 
PERIOD WILL DECREASE DURING MON AS HIGH PRESSURE MOVES OVER HEAD. 
SPEEDS WILL DROP UNDER 10 KT BY MON EVENING...BECOMING LIGHT AND 
VARIABLE MON NIGHT. HIGH SHIFTS OFFSHORE FOR TUE WITH RETURN FLOW 
SLOWLY RISING INTO THE 10 TO 15 KT RANGE LATE TUE AND TUE NIGHT. 
SEAS WILL RUN 2 TO 3 FT FOR A MAJORITY OF THE PERIOD.

&&

.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 2 PM THIS AFTERNOON TO 8 AM EDT
     SATURDAY FOR AMZ250-252-254-256.  

&&

$$

NEAR TERM...RJD
SHORT TERM...III
LONG TERM...III
AVIATION...SGL/RJD