000
FXUS62 KILM 190535
AFDILM

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WILMINGTON NC
135 AM EDT SUN MAY 19 2013

.SYNOPSIS...
RAIN CHANCES WILL INCREASE THE NEXT COUPLE OF DAYS AS WEAK LOW
PRESSURE ALOFT DRIFTS ACROSS THE CAROLINAS...WITH DAY AND NIGHT
TIME TEMPERATURES RUNNING NEAR NORMAL FOR MIDDLE MAY. BERMUDA
HIGH PRESSURE WILL BUILD TOWARD THE EAST COAST MID THROUGH LATE
WEEK...BRINGING A DRYING AND WARMING TREND.

&&

.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
AS OF 130 AM SUNDAY...SCATTERED SHOWERS SHOULD REMAIN LIMITED TO
JUST THE I-95 COUNTIES OVERNIGHT WHERE RADAR ACTUALLY SHOWS A LITTLE
NEW DEVELOPMENT JUST SOUTH AND WEST OF FLORENCE IN THE PAST 30
MINUTES. OTHERWISE THE ONLY UPDATE TO THE FORECAST WAS TO RAISE
FORECAST LOWS BY A FEW DEGREES AT THE BEACHES AND OFFSHORE WHERE A
NEARLY TROPICAL ONSHORE FLOW WILL CONTINUE THROUGH DAYBREAK.
PREVIOUS DISCUSSION FROM 1100 PM SATURDAY FOLLOWS...

TWO AREAS OF CONVECTION...1 ACROSS THE WESTERN ILM CWA...AND THE
OTHER JUST NORTH OF THE ILM CWA...WILL BOTH CONTINUE THE
WEAKENING/DISSIPATING TREND AS NOTED BY THE KLTX AND SURROUNDING
88DS. A SFC BASED MARINE STABLE AIR MASS ACROSS THE FA WILL MODERATE
OVERNIGHT...MEANING THE DEPTH OF THIS AIR MASS TRANSPORTED INLAND BY
THE SEA BREEZE WILL DECREASE. PCPN DEVELOPMENT WEST OF THE ILM CWA
HAS REMAINED STEADY OR HAS SLIGHTLY INCREASED. THIS PCPN ACTIVITY
HAS BEEN AIDED BY FORCING/DYNAMICS FROM A MID-LEVEL VORT...THAT WAS
ONCE ASSOCIATED WITH THE CLOSED UPPER LOW THAT AFFECTED THE SOUTHERN
U.S. DURING THE PAST MID-WEEK PERIOD. WILL MAINTAIN CHANCE POPS
ACROSS THE WESTERN 1/3RD OF THE ILM CWA TO ACCOUNT FOR ANY OF THE
EASTWARD MOVING CONVECTION MAKING IT TO THE FA. IT WILL ENCOUNTER AN
AIR MASS HAVING BEEN DEPLETED BY PREVIOUS CONVECTION ALONG WITH A
MODERATING SFC BASED MARINE LAYER. WILL INDICATE NO POPS ALONG THE
IMMEDIATE COAST. HAVE INCLUDED PATCHY FOG ACROSS PORTIONS OF THE FA.
THIS A RESULT OF SFC DEWPOINTS IN THE 60S...PROGGED SFC DEWPOINT
DEPRESSIONS LESS THAN 5 DEGREES...WINDS LIKELY TO DECOUPLE ACROSS
PORTIONS OF THE FA...AND AVBL MOISTURE FROM RECENT RAINS. DEBRIS
CLOUDINESS WILL KEEP THE RADIATIONAL FOG COVERAGE TO A MINIMUM.

&&

.SHORT TERM /6 AM SUNDAY MORNING THROUGH MONDAY NIGHT/...
AS OF 3 PM SATURDAY...BATCHES OF SHORT-WAVE ENERGY EVIDENT IN
VAPOR ANIMATIONS TWISTING AND CURLING WELL UPSTREAM OVER THE MID
MISSISSIPPI VALLEY WILL APPROACH AND MOVE ACROSS THE CAROLINAS
SUNDAY AND MONDAY. COLUMN MOISTURE/PWAT VALUES WILL INCREASE AND
WE MAY SEE A FEW DEGREES OF H7 COOLING AS THESE DISTURBANCES MOVE
ACROSS THE AREA. THESE SUBTLE FEATURES OF SLIGHT COOLING ALOFT AND
INCREASING MID-LEVEL MOISTURE MAKE A LARGER DIFFERENCE THIS TIME
OF YEAR WHEN CONVECTION BREWS. WILL MAINTAIN HIGH SCATTERED TO
LIKELY POP VALUES SUNDAY INTO MONDAY GIVEN THESE ANTICIPATED
INGREDIENTS. CONSIDERABLE CLOUDINESS WILL TEMPER MAX TEMPS IN THE
LOW 80S MOST LOCATIONS BOTH SUNDAY AND MONDAY...WHILE KEEPING
NIGHT TIME READINGS VERY MILD. AN H7 COLD FRONT WILL BRING A
WIND-SHIFT AND DRYING ALOFT LATE MONDAY AND HAVE TAPERED POP VALUES
INTO VERY EARLY TUESDAY. EXPECTED RAIN AMOUNTS/QPF BOTH DAYS ADDS UP
TO A 1/2 TO 1 INCH ALONG AND NEAR THE COAST...AND POTENTIALLY 1-2
INCHES OVER OUR WESTERN ZONES AND FAR INTERIOR FOR THE PERIOD SUNDAY
AND MONDAY.

&&

.LONG TERM /TUESDAY THROUGH SATURDAY/...
AS OF 3 PM SATURDAY...BROAD UPPER RIDGING IN PLACE ON TUESDAY AS
WILL BE WEST ATLANTIC SURFACE HIGH PRESSURE. MAIN POINT OF
UNCERTAINTY REGARDING MID LEVEL SHORTWAVE/PRONOUNCED SHEAR AXIS.
SOME GUIDANCE HAS IT ALREADY OFFSHORE FOR WHAT SHOULD BE A RATHER
QUIET AFTERNOON WITH NEAR SEASONABLE TEMPS WHILE OTHERS HAVE IT
ALONG THE COAST FOR SLIGHTLY MORE ACTIVE AFTERNOON OF CONVECTION.
GIVEN HOW WEAK THE FLOW IS WILL SHOW LOW END CHANCE POPS. WITH THIS
FEATURE OUT OF THE PICTURE WEDNESDAY EXPECT A FURTHER WARMUP AND
MERELY ISOLATED CONVECTION ALONG BOUNDARIES LIKE THE SEA BREEZE AND
OUTFLOW FROM ANY ACTIVITY FROM THE PRIOR AFTERNOON. A VERY GRADUAL
UPTICK IN MID LEVEL SWRLY FLOW EXPECTED THURSDAY AHEAD OF
TROUGHINESS STRENGTHENING OVER OH/UPPER MS VALLEYS. THURSDAY THUS
BEGINS AN UPWARD TREND IN CONVECTIVE COVERAGE AS MOISTURE MAY
DEEPEN. THE ACTUAL CYCLONIC FLOW ASSOC WITH THE TROUGH WILL
OVERSPREAD THE REGION THURSDAY NIGHT INTO FRIDAY FURTHER BOLSTERING
RAIN CHANCES AND TEMPERING DAYTIME HIGHS BACK TOWARDS CLIMO.

&&

.AVIATION /06Z SUNDAY THROUGH THURSDAY/...
AS OF 06Z...SCATTERED MAINLY LIGHT SHOWERS ARE POSSIBLE THROUGH
DAYBREAK AT FLO/LBT WITHIN A BAND OF THICKER MID-LEVEL MOISTURE LEFT
OVER FROM SATURDAY`S INLAND THUNDERSTORM ACTIVITY. PLENTY OF BKN
MID-LEVEL CLOUDS COULD BECOME ACCOMPANIED BY SCATTERED LOW CLOUDS AS
SURFACE TEMPERATURES APPROACH DEWPOINT TEMPERATURES OVER THE NEXT
FEW HOURS. THE ATMOSPHERE APPEARS SET FOR ANOTHER ROUND OF INLAND
SHOWERS AND STORMS SUNDAY AFTERNOON. BIGGEST THREAT WILL BE REDUCED
VSBY IN HEAVY RAINFALL. LESSER CHANCES FOR SHOWERS AND STORMS ARE
EXPECTED AT THE COAST ALTHOUGH THERE ARE SOME INDICATIONS IF
ANYTHING AFFECTS THE ILM/CRE/MYR IT COULD BE A LATE MORNING EVENT
RATHER THAN AFTERNOON LIKE FARTHER INLAND. OTHERWISE GENERALLY SOUTH
SURFACE WINDS WILL INCREASE TO AROUND 10 KT DURING THE DAY.

EXTENDED OUTLOOK...AFTN SHOWERS/TSTMS POSSIBLE AGAIN MONDAY.
OTHERWISE PREVAILING VFR.

&&

.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 130 AM SUNDAY...LOOKS LIKE A GENERALLY DRY REMAINDER OF THE
NIGHT ACROSS THE COASTAL WATERS AS THE BETTER MID-LEVEL MOISTURE
REMAINS INLAND. THE ONLY CHANGE TO THE FORECAST WAS TO RAISE
TEMPERATURES BY AN AVERAGE OF 5 DEGREES THROUGH DAYBREAK AS A MOIST
NEARLY TROPICAL SOUTH WIND CONTINUES. PREVIOUS DISCUSSION FROM 1100
PM FOLLOWS...

LOWERED POPS RELATED TO THE CONVECTION TRYING TO REMAIN TOGETHER AS
IT MOVES OFF THE NORTH AND SOUTH CAROLINA MAINLAND INTO THE ILM
COASTAL WATERS. RATHER THICK SFC BASED STABLE MARINE LAYER CONTINUES
TO HAVE A NEGATIVE IMPACT ON CONVECTION DEVELOPMENT AS A WHOLE...AS
WELL AS ITS SUSTAINABILITY AFTER MOVING OFF THE MAINLAND. THE SFC
FRONTAL BOUNDARY WILL CONTINUE RETURNING NORTHWARD OVERNIGHT INTO
SUNDAY...FURTHER AWAY FROM THE ILM COASTAL WATERS. PROGGED SFC
PRESSURE PATTERN AND GRADIENT WILL RESULT IN A SE-S WIND AROUND 10
KT...OCCASIONALLY 15 KT ACROSS THE ILM SC WATERS. SIGNIFICANT SEAS
WILL RUN 2 FT...EXCEPT UP TO 3 FT FAR THE ILM SC WATERS. A 1 TO 2
FOOT PSEUDO EASTERLY GROUND SWELL AT 8 TO 9 SECOND PERIODS WILL
DOMINATE SIG. SEAS...WITH ONLY A 1-2 FOOT CONTRIBUTION FROM A 3 TO 4
SECOND PERIOD WIND WAVE.

SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
AS OF 3 PM SATURDAY...LESS THAN IDEAL MARINE CONDITIONS EXPECTED
SUNDAY AND MONDAY BUT NO HEADLINES OR CAUTIONARY STATEMENTS ARE
EXPECTED AT THIS TIME. SW WINDS OF 15-20 KT AND 4 FT SEAS WILL
MARK A GOOD PORTION OF THE MARINE FORECAST SUNDAY THROUGH MONDAY
AS BERMUDA HIGH PRESSURE BUILDS WEST TOWARD THE COAST AND LOWER
PRESSURE INLAND INTERACT. SEAS WILL BE COMPOSED OF GROWING S WAVES
WITH PERIODS AROUND 6 SECONDS AND LOW-AMPLITUDE ESE SWELL WAVES.
MARINERS SHOULD CONSIDER GETTING A FIX ON RADAR TRENDS BEFORE
HEADING OUT SINCE TSTMS MAY DOT THE WATERS...FAVORED MOSTLY LATE
SUNDAY INTO MONDAY. WINDS AND WAVES WILL BE LOCALLY HIGHER IN AND
NEAR TSTMS.

LONG TERM /TUESDAY THROUGH WEDNESDAY/...
AS OF 3 PM SATURDAY...SOUTHWESTERLY FLOW SHOULD PERVADE THE
ENTIRE PERIOD AS HIGH PRESSURE REMAINS NEARLY STATIONARY ACROSS
THE WESTERN ATLANTIC. THE FLOW MAY INCREASE TOWARDS THE END OF THE
PERIOD AS RIDGE AXIS INTO THE CAROLINAS DEVELOPS AND MOVES TO THE
NORTH. THIS COULD ALSO STEER JUST ENOUGH SWELL ENERGY INTO THE
REGION TO BUILD SEAS A FOOT OR TWO.

&&

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

&&

$$

SYNOPSIS...MJC
NEAR TERM...DC/TRA
SHORT TERM...MJC
LONG TERM...MBB
AVIATION...SGL/TRA