AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WILMINGTON NC
1042 PM EDT THU MAY 23 2013
.SYNOPSIS...
A COLD FRONT WILL MOVE ACROSS THE AREA LATE TONIGHT AND EARLY
FRIDAY...ENDING THE RISK FOR SHOWERS AND THUNDERSTORMS AND USHERING
IN MUCH COOLER AND DRIER AIR FOR THE REMAINDER OF THE WEEK AND
THROUGH MUCH OF THE HOLIDAY WEEKEND. HIGH PRESSURE WILL PUSH
OFFSHORE EARLY NEXT WEEK...ALLOWING FOR A GRADUAL WARM UP AS THE
RISK FOR SHOWERS AND THUNDERSTORMS RETURNS.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
AS OF 10 PM THURSDAY...A WEAK MID-LEVEL SHORTWAVE AND A COLD FRONT
WILL MOVE ACROSS THE AREA OVERNIGHT. ALTHOUGH THE AFTERNOON AND EVE
SHOWERS AND THUNDERSTORMS HAVE DISSIPATED ACROSS THE EASTERN
CAROLINAS...THERE IS STILL A BATCH OF CONVECTION TO OUR NW...
DIRECTLY ALONG AND JUST AHEAD OF THE COLD FRONT.
THE ADDED LIFT ASSOCIATED WITH THE AFOREMENTIONED FEATURES MAY JUST
BE ABLE TO SUSTAIN THE CONVECTION DESPITE THE ADVERSE TIMING. ALSO
SEVERAL OF THE MODELS TO INCLUDE THE HIGHER RESOLUTION ARE
INDICATING RENEWED CONVECTION AS THE FRONT SWINGS THROUGH OVERNIGHT
AND EARLY FRI MORNING. THEREFORE...WILL SHOW A GOOD CHANCE OF
SHOWERS AND ISOLATED THUNDERSTORMS...PRIMARILY COINCIDENT WITH
FRONTAL PASSAGE.
GIVEN THE AIRMASS DOES BEGIN TO SLOWLY DRY OUT...FROM W TO E...FROM
THIS POINT FORWARD...WILL TAKE MENTION OF HEAVY RAIN OUT OF THE
FORECAST AS WE DO EXPECT OVERNIGHT CONVECTION TO BE VERY PROGRESSIVE.
WINDS WILL SHIFT TO NW WITH FRONTAL PASSAGE...FIRST ACROSS
WESTERNMOST AREAS AROUND 3 AM AND LASTLY ALONG THE IMMEDIATE COAST
AROUND AND SHORTLY AFTER SUNRISE. DECIDEDLY COOLER AND DRIER AIR
WILL WORK INTO THE EASTERN CAROLINAS ON FRI. THERE SHOULD BE JUST
ENOUGH MIXING TO PRECLUDE THE DEVELOPMENT OF SIGNIFICANT FOG AND
WILL NOT INCLUDE MENTION AT THIS TIME.
GUIDANCE IS IN EXCELLENT AGREEMENT FOR OVERNIGHT MINIMUMS SO WENT
WITH CONSENSUS...LOWER TO MID 60S. MOST COASTAL LOCATIONS ARE NOT
EXPECTED TO DROP BELOW THE UPPER 60S TO NEAR 70 DEGREES GIVEN THE
INFLUX OF LOWER DEWPOINTS WILL NOT REACH THIS AREA UNTIL FRI
MORNING...LASTLY ACROSS THE CAPE FEAR REGION.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH SATURDAY NIGHT/...
AS OF 3 PM THURSDAY...COLD FRONT WILL BE OFF THE COAST AT THE START
OF THE PERIOD WITH MUCH COOLER AND DRIER AIR STARTING TO FILTER IN
AS CANADIAN HIGH BUILDS INTO THE AREA. LIGHT PRECIP MAY LINGER
INTO THE MID-LATE MORNING HOURS ALONG THE SE NC COAST BUT MID
LEVEL DRYING WILL BRING AN END TO ANY PRECIP BY MIDDAY. AIR MASS
CONTINUES TO DRY OUT AS SUBSIDENCE BEHIND 5H TROUGH ARRIVES FRI
AFTERNOON. DESPITE PASSAGE OFF COLD POOL OVERHEAD DURING PEAK
HEATING DO NOT ANTICIPATE ANY AFTERNOON PRECIP. FORECAST SOUNDINGS
SHOW OVERPOWERING DRY AIR AND SUBSIDENCE. THINK EVEN CLOUD COVER
WILL BE LIMITED TO NON EXISTENT BY EARLY AFTERNOON GIVEN THE
STRENGTH OF THE SUBSIDENCE. COLD ADVECTION STARTS OFF SLOW BUT
GAINS STRENGTH WITH PASSAGE OF 5H TROUGH AXIS. HIGHS ARE LIKELY TO
OCCUR BY MIDDAY OR SO AND THEN HOLD STEADY OR DROP AS COLD AIR
ARRIVES. BOTH FRI AND SAT WILL BE ON BREEZY SIDE.
DEEP NORTHWEST FLOW SAT WILL KEEP THE REGION COOL AND DRY DESPITE
PLENTY OF LATE MAY SUNSHINE. PRECIPITABLE WATER VALUES STRUGGLE TO
REACH HALF AN INCH...ABOUT 2 STANDARD DEVIATIONS BELOW NORMAL.
COLD ADVECTION CONTINUES SAT WITH 850 TEMPS STRUGGLING AND
ULTIMATELY FAILING TO REACH 10C. HIGHS SAT STRUGGLE TO REACH MID
70S...FOR MOST AREAS 80 DEGREES SEEMS UNOBTAINABLE.
FRI NIGHT WILL BE A DECENT THOUGH FAR FROM AN IDEAL RADIATIONAL
COOLING NIGHT. DESPITE THE LACK OF A STRONG RADIATION COOLING
COMPONENT LOWS STILL END UP WELL BELOW CLIMO. MOST AREA WILL DROP
BELOW 50 WITH INLAND AREAS POTENTIALLY REACHING MID 40S...A
TESTAMENT TO THE STRENGTH OF THE COLD ADVECTION. WEAKENING COLD
ADVECTION AND AIR MASS MODIFICATION OFFSET WHAT SHOULD BE BETTER
RADIATIONAL COOLING CONDITIONS SAT NIGHT. LOWS WILL BE SIMILAR TO
FRI NIGHT...THOUGH SLIGHTLY WARMER IN MOST AREAS. SOME GUIDANCE
IS SHOWING WEAK MID LEVEL FRONTOGENESIS DEVELOPING SOUTH OF THE
AREA LATE SAT NIGHT. DEPENDING ON IF/WHERE THIS DEVELOPS IT COULD
PRODUCE SOME CLOUD COVER...KEEPING LOWS A LITTLE WARMER THAN
FORECAST.
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
AS OF 3 PM THURSDAY...AIR MASS WILL BEGIN TO MODIFY EARLY NEXT
WEEK LEADING TO MORE SEASONABLE WEATHER BY MID WEEK AS HIGH
PRESSURE NEARLY OVERHEAD ON SUNDAY SHIFTS OFF SHORE THROUGH MONDAY
WITH A WARMER AND MOISTER RETURN FLOW SETTING UP. 850 TEMPS
STARTING OUT AROUND 8C ON SUNDAY WILL BE BACK UP TO 15 C BY LATE
TUES. DEWPOINT TEMPS IN THE 40S ON SUNDAY WILL CREEP BACK UP
REACHING OVER 60 BY MID WEEK. THE DRIER AIR INITIALLY WILL CREATE
GREATER DIURNAL SWINGS WITH TEMPS DROPPING DOWN TO THE LOWER END
OF 50S ON SUN NIGHT BUT REMAINING IN THE MID 60S BY MID WEEK. MAX
TEMPS WILL REMAIN IN THE 70S MOST PLACES ON SUNDAY AND MONDAY BUT
TUES THROUGH THURS TEMPS WILL BE BACK IN THE LOW TO MID 80S.
MID TO UPPER TROUGH WILL CONTINUE TO LIFT OFF TO THE NORTHEAST AS
RIDGE OVER THE CENTRAL STATES SHIFTS EAST THROUGH THE PERIOD. SOME
UPPER LEVEL MOISTURE AND MINOR PERTURBATIONS WILL RIDE DOWN INTO THE
CAROLINAS IN THE DEEP NW TO W FLOW THROUGH WED BEFORE RIDGE SHIFTS
EAST AND BUILDS UP THE EAST COAST BY THURS. HIGH PRESSURE AT THE
SURFACE WILL CONTINUE TO MOVE FARTHER OFF SHORE BUT WILL RIDGE BACK
INTO THE CAROLINAS THROUGH MUCH OF NEXT WEEK. WITH LOW LEVEL
MOISTURE RETURNING MON INTO TUES SO WILL THE CHANCE OF AFTERNOON CU
BUILDING UP AND LOW END CHC OF LOCALIZED SHWR ACTIVITY...MAINLY
ASSOCIATED WITH SEA BREEZE BOUNDARY AS IT PUSHES INLAND EACH DAY.
OVERALL...ASIDE FROM SOME HIGH CLOUDS STREAMING OVER THE
AREA...EXPECT PLENTY OF SUNSHINE AND LIMITED SHWR ACTIVITY AS
SUBSIDENCE INCREASES ALOFT THROUGH THE WEEK.
&&
.AVIATION /00Z FRIDAY THROUGH TUESDAY/...
AS OF 00Z...CURRENT RADAR IMAGERY SHOWS A LINE OF T-STORMS TRACKING
ACROSS GEORGETOWN AND HORRY COUNTIES THIS EVENING. THESE T-STORMS
WILL IMPACT KMYR/KCRE JUST AFTER 00Z...AND TEMPO IFR VSBYS ARE
EXPECTED WITH HEAVY PCPN AND CLOUD-TO-GROUND LTG. ISOLATED STORMS
WILL ALSO MOVE THROUGH KFLO SHORTLY WITH TEMPO MVFR/IFR POSSIBLE.
SHOWERS/STORMS ARE EXPECTED TO RAPIDLY DECREASE IN COVERAGE TONIGHT.
ABUNDANT LOW-LEVEL MOISTURE AHEAD OF AN APPROACHING COLD FRONT COULD
SUPPORT MVFR/IFR CIGS/VSBYS OVERNIGHT. IFR CONFIDENCE IS LOW
ATTM...BUT HAVE INCLUDED MVFR AT ALL TERMS. COLD FRONT WILL MOVE
THROUGH KFLO/KLBT AROUND 09Z AND REACH THE COASTAL TERMS BY 12Z.
CLOUD COVER WILL DIMINISH ON FRIDAY WITH NORTHWEST WINDS 10-15 KTS
AND GUSTS OF 20+ KTS.
EXTENDED OUTLOOK...MORNING FOG POSSIBLE MONDAY AND TUESDAY.
OTHERWISE VFR.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 10 PM THURSDAY...SW WINDS WILL CONTINUE IN ADVANCE OF A COLD
FRONT. THIS FRONT WILL PUSH ACROSS THE WATERS AFTER SUNRISE...
SHIFTING WINDS TO NW AND THEN TO N DURING FRI. SUSTAINED WIND SPEEDS
ARE EXPECTED TO REMAIN IN THE 10 TO 15 KT RANGE OVERNIGHT...BUT
LOCALLY HIGHER IN ANY CONVECTION THAT MOVES OFFSHORE. SEAS WILL
RANGE FROM 2 TO 4 FT...BUT UP TO 5 FT ACROSS THE OUTERMOST WATERS
NEAR FRYING PAN SHOALS BUOY. A SE 7 TO 8 SECOND SWELL WILL PERSIST
THROUGH FRI.
SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
AS OF 3 PM THURSDAY...COLD FRONT QUICKLY MOVES EAST OF THE WATERS
FRI WITH STRONG NORTHWEST FLOW DEVELOPING. COMBINATION OF TIGHT
GRADIENT AND STRONG COLD ADVECTION WILL HAVE WIND SPEEDS APPROACHING
20 KT SUSTAINED FRI AND FRI NIGHT WITH HIGHER GUSTS. SPEEDS
DECREASE FOR SAT AS COLD ADVECTION AND GRADIENT WEAKEN. WINDS VEER
TO MORE NORTHERLY FOR THE SECOND HALF OF THE PERIOD WITH SPEEDS
SLOWLY DROPPING. SPEEDS CLOSE TO 15 KT SAT BEFORE DROPPING NEAR 10
KT SAT NIGHT. SEAS 2 TO 5 FT IN STRONG OFFSHORE FLOW FRI WILL
SUBSIDE TO 2 TO 4 FT FOR SAT IN RESPONSE TO DECREASING WINDS.
SEAS MAY BE QUITE TREACHEROUS DESPITE LACK OF HEADLINES WITH STEEP
NORTHWEST WIND WAVE ON TOP OF SOUTHEAST SWELL.
LONG TERM /SUNDAY THROUGH TUESDAY/...
AS OF 3 PM THURSDAY...HIGH PRESSURE NEARLY OVERHEAD ON SUNDAY
WILL SHIFT FURTHER OFF SHORE MONDAY THROUGH TUESDAY. THEREFORE
LIGHTER AND MORE VARIABLE WINDS ON SUNDAY WILL INCREASE SLIGHTLY
AS SOUTHERLY RETURN FLOW SETS UP BY MONDAY. LIGHTER AND MORE
VARIABLE N TO NW WINDS ON SUNDAY 10 KTS OR LESS WILL BACK SLOWLY
TO THE WEST AND EVENTUALLY SOUTHERLY BY MONDAY. SEAS WILL STAY
LESS THAN 3FT MOST WATERS AND NEAR SHORE WILL BE DOMINATED MORE BY
THE SEA BREEZE ESPECIALLY TOWARD MID WEEK WHEN A WARMING TREND
OCCURS ALLOWING FOR A BETTER SEA BREEZE CIRCULATION TO SET UP. BY
MONDAY AFTN WINDS WILL SHIFT SOUTH RUNNING AROUND 10 TO 15 KTS
THROUGH MID WEEK NEXT WEEK. MAY SEE A SLIGHT RISE IN SEAS THROUGH
MID WEEK BUT OVERALL REMAINING 3 FT OR LESS WITH SLIGHT INCREASE
AND CHOP EACH AFTERNOON IN SEA BREEZE.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...RJD
SHORT TERM...III
LONG TERM...RGZ
AVIATION...BJR
