000
FXUS62 KCHS 180811
AFDCHS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
411 AM EDT SAT MAY 18 2013

.SYNOPSIS...
AN UPPER DISTURBANCE WILL MOVE NORTH OF THE AREA THROUGH MONDAY.
ATLANTIC HIGH PRESSURE WILL BE THE DOMINANT FEATURE THROUGH MUCH OF
NEXT WEEK BEFORE A COLD FRONT APPROACHES FRIDAY NIGHT AND SATURDAY.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
PRE-DAWN...CONVECTIVE RAINS HAVE CAMPED OUT OVERNIGHT ACROSS NORTH
GEORGIA AS A MID LEVEL SHORT WAVE LIFTS TOWARD THE WESTERN CAROLINAS.
OUR REGION HAS REMAINED DRY WITH CLOUDS SLOW TO WORK INTO INLAND
ZONES. TEMPS WERE IN THE 60S ONCE AGAIN THIS MORNING WITH LIGHT OR
NEAR CALM WINDS MANY AREAS.

QUITE A FEW TRICKY ELEMENTS TO OUR FORECAST TODAY...HOWEVER THE
OVERALL SYNOPTIC PATTERN REMAINS SIMILAR WITH THE OFFSHORE ATLC
RIDGE REFUSING TO BUDGE AND THE SURFACE RIDGE AXIS STILL POKING W
THROUGH NORTHERN FLORIDA.

DEEPER MOISTURE BETWEEN 850MB-500MB AND A POCKET OF UPPER FORCING
WITH THE UPSTREAM SHORT WAVE IS EXPECTED TO REMAIN OVER THE
WESTERN CAROLINAS INTO VIRGINIA TODAY. AS THE 925MB-850MB TROUGH
PULLS MORE N THAN E WITH TIME....THERE WILL LIKELY BE A LOW LEVEL
TROUGH/CONVERGENCE ZONE SETTING UP ALONG AND JUST W OF INTERSTATE
95 THIS AFTERNOON. MODEL SOUNDINGS SHOW THE ATMOSPHERE BECOME MORE
CONDUCIVE TO CONVECTIVE DEVELOPMENT LATER TODAY...ESPECIALLY
ANCHORED IN THIS FAIRLY NARROW CORRIDOR OF LOW LEVEL MOISTURE
CONVERGENCE. MID LEVEL INSTABILITY IS NOT VERY IMPRESSIVE WITH MID
LEVEL LAPSE RATES -5.5C TO -6C IN THE 700MB TO 500MB LAYER AND
SHOWALTER INDICES RUNNING SLIGHTLY POSITIVE. SIMILAR TO PREVIOUS
THINKING WE CHANNELED SLIGHT CHANCE TO CHANCE POPS ALONG THE I-95
CORRIDOR. IT STILL LOOKS UNLIKELY WE WILL SEE MANY INTENSE UPDRAFTS
AND MUCH IN THE WAY OF SEVERE WEATHER.

SKY COVER PROGS ARE TOUCH AND GO AS TIME/HEIGHT CROSS SECTIONS
SHOWING COPIOUS HIGH LEVEL MOISTURE STREAMING THROUGH BUT PRE-DAWN
SATELLITE IMAGERY HINTING THAT WE MAY SEE MORE IN THE WAY OF
SUNSHINE AT LEAST OVER THE SE HALF OF THE FORECAST AREA. OF COURSE
CLOUDS WILL HAVE AN IMPACT ON HIGH TEMPS AND OVERALL PERSISTENCE
WAS MAINTAINED WITH MAX TEMPS IN THE MID TO UPPER 80S.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY/...
ANY EARLY EVENING CONVECTION WITH THE SEA BREEZE MAY TEND TO DRIFT
TOWARD THE COAST BUT ALSO LIKELY DISSIPATE QUICKLY WITH LOSS OF
SURFACE HEATING. OVERNIGHT...MODELS DELIVER A BIT MORE UPPER LEVEL
NW FLOW AND DEEPER LAYERED INSTABILITY WHICH COULD LEAD TO ISOLATED
CONVECTIVE RAINS JUST ABOUT ANYWHERE LATE...SLIGHT CHANCE POPS
AFTER MIDNIGHT WERE MAINTAINED. PARTLY TO MOSTLY CLOUDY SKIES ON
TAP WITH TEMPS IN THE 60S ONCE AGAIN.

A FAIRLY ROBUST SHORTWAVE TROUGH WILL BE NORTH OF THE AREA ON SUNDAY
BUT DROP SOUTHEAST INTO CENTRAL SOUTH CAROLINA ON MONDAY. MEANWHILE
WITH ATLANTIC HIGH PRESSURE JUST OFF THE COAST...A SOUTH-SOUTHEAST
FLOW WILL MAINTAIN A FAIRLY JUICY AIRMASS. PW READINGS POTENTIALLY
EXCEED 1.80 INCHES ON MONDAY. SOME MID AND HIGH CLOUDS WILL SOMEWHAT
LIMIT HEATING SUNDAY AND MONDAY BUT HIGHS WILL LIKELY STILL CLIMB
INTO THE UPPER 80S FAR INLAND WITH MIDDLE 80S ELSEWHERE. THE UPPER
HEIGHT FALLS AND STEEPENING MID-LEVEL LAPSE RATES ASSOCIATED WITH
THE SHORTWAVE ENERGY WILL PROVIDE A FAVORABLE ENVIRONMENT FOR
SCATTERED TO NUMEROUS SHOWERS AND TSTMS BOTH DAYS. INSTABILITY
PARAMETERS INDICATE SOME STRONG STORMS WILL BE POSSIBLE EITHER DAY.
IN ADDITION...WITH PW VALUES NEAR THE 99TH PERCENTILE FOR MAY AND
0-6 KM MEAN WINDS LESS THAN 10 KT...LOCALLY HEAVY RAINFALL WILL
ALSO BE A CONCERN.

THE UPPER VORT ENERGY WILL SHIFT OFFSHORE MONDAY NIGHT WITH
SHORTWAVE RIDGING FOR TUESDAY. ONLY ISOLATED AIRMASS CONVECTION
EXPECTED TUESDAY...PRIMARILY DRIVEN BY THE SEABREEZE SO WE HAVE
SLIGHT CHANCE POPS. TEMPS WILL BE A FEW DEGREES WARMER DUE TO MORE
SUN.

&&

.LONG TERM /TUESDAY NIGHT THROUGH FRIDAY/...
A RATHER WARM PATTERN PERSISTS IN THE LONG TERM AS THE AREA SITS ON
THE WESTERN SIDE OF AN UPPER RIDGE WITH ATLANTIC HIGH PRESSURE
OFFSHORE. RAIN CHANCES WILL INCREASE A BIT LATE IN THE WEEK AS AN
UPPER TROUGH APPROACHES FROM THE WEST AND A COLD FRONT DROPS INTO
THE AREA FRIDAY NIGHT OR SATURDAY.

&&

.AVIATION /08Z SATURDAY THROUGH WEDNESDAY/...
VFR CONDITIONS WILL PREVAIL AT KCHS AND KSAV THROUGH 06Z SUNDAY.
ISOLATED CONVECTION COULD DEVELOP LATER THIS AFTERNOON MAINLY
WEST OF THE I-95 CORRIDOR...PROBABILITIES OF ANY CONVECTION
IMPACTING THE TERMINALS ARE TOO LOW TO INCLUDE IN THE FORECAST AT
THIS TIME.

EXTENDED AVIATION OUTLOOK...PRIMARILY VFR. LOW CHANCES OF DIRECT
IMPACTS FROM ISOLATED TO SCATTERED MAINLY AFTERNOON
SHOWERS/THUNDERSTORMS THROUGH EARLY NEXT WEEK.

&&

.MARINE...
ATLANTIC HIGH PRESSURE WILL PERSIST OFF THE COAST WITH A SOUTH TO
SOUTHEAST FLOW RANGING FROM 10 TO 15 KNOTS PERSISTING. SEAS WILL
AVERAGE 2 TO 4 FEET THROUGH WEDNESDAY WITH SOME BUILDING OF SEAS
LATE WEEK AS THE GRADIENT TIGHTENS A BIT.

&&

.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...NONE.

&&

$$

SYNOPSIS...
NEAR TERM...
SHORT TERM...JRL
LONG TERM...JRL
AVIATION...
MARINE...JRL

000
FXUS62 KCHS 180510
AFDCHS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
110 AM EDT SAT MAY 18 2013

.SYNOPSIS...
AN UPPER DISTURBANCE WILL MOVE NORTH OF THE AREA THROUGH THE WEEKEND
AS ATLANTIC HIGH PRESSURE BUILDS ACROSS THE REGION. HIGH PRESSURE
WILL BE THE DOMINANT FEATURE THROUGH MUCH OF NEXT WEEK BEFORE A COLD
FRONT POSSIBLY APPROACHES ON FRIDAY.

&&

.NEAR TERM /UNTIL 6 AM THIS MORNING/...
ATLANTIC HIGH PRESSURE AT THE SURFACE WILL PREVAIL OVERNIGHT...AS A
SHORT WAVE TROUGH APPROACHES FROM THE WEST. MID AND HIGH LEVEL
CLOUDS WILL INCREASE IN COVERAGE AS THE TROUGH NEARS. THE
INCREASE IN CLOUDS AND A LIGHT SOUTHERLY FLOW WILL KEEP LOW
TEMPERATURES MAINLY IN THE MID 60S TONIGHT...WITH UPPER 60S NEAR
THE IMMEDIATE COAST.

&&

.SHORT TERM /6 AM THIS MORNING THROUGH MONDAY/...
SATURDAY AND SATURDAY NIGHT...A DEEP AND EXPANSIVE LONGWAVE UPPER
RIDGE WILL ENCOMPASS MUCH OF THE EASTERN HALF OF THE COUNTRY WITH AN
EMBEDDED SHORTWAVE TROUGH POSITIONED NEAR THE OHIO VALLEY. THIS
BAGGY TROUGH CAUGHT WITHIN THE LARGER SCALE RIDGE WILL SLOWLY
MEANDER ACROSS THE APPALACHIANS AND TOWARDS THE EAST COAST. PIECES
OF VORT ENERGY ASSOCIATED WITH THIS FEATURE WILL CROSS THE FORECAST
AREA WITH SOME LOWERING OF HEIGHTS. AT THE SURFACE...THE FORECAST
AREA WILL BE IN THE SOUTHERLY FLOW REGIME AROUND HIGH PRESSURE OVER
THE ATLANTIC. MODEL SOUNDINGS SHOW THE ATMOSPHERE BECOME MORE
CONDUCIVE TO CONVECTIVE DEVELOPMENT IN THE AFTERNOON COMPARED TO
PREVIOUS DAYS...ESPECIALLY ALONG AND WEST OF I-95. AREAS EAST OF
I-95 ARE PROGGED TO SEE WARMER 850 MB TEMPS AND A CAP THAT WILL
LIKELY KEEP DEVELOPMENT ISOLATED AT BEST. FURTHER WEST...THE CAP
ERODES AND WITH COOLING/MOISTENING PROFILES...SCATTERED
SHOWERS/THUNDERSTORMS ARE EXPECTED. THE EXPECTATION IS THAT THIS
WILL BE JUST GARDEN VARIETY SHOWERS/STORMS AS NONE OF THE SEVERE
WEATHER PARAMETERS ARE PARTICULARLY IMPRESSIVE. HIGHS WILL CONTINUE
A FEW DEGREES ABOVE NORMAL REACHING THE MID/UPPER 80S.
OVERNIGHT...ONGOING CONVECTION SHOULD BECOME INCREASINGLY CONFINED
FURTHER WEST AND NORTH AS THE SEABREEZE PUSHES INLAND. I HAVE
MAINTAINED A SMALL AREA OF SLIGHT CHANCES THROUGH THE NIGHT CLOSER
TO THE TROUGH AND BETTER MOISTURE. LOWS WILL BE MILD AND IN THE
MID/UPPER 60S.

SUNDAY THROUGH MONDAY...THIS WILL BE THE MOST ACTIVE TIME PERIOD
WITH THE BEST COVERAGE OF SHOWERS/STORMS. THE BAGGY SHORTWAVE TROUGH
AND ASSOCIATED PASSING VORT MAXES WILL LINGER OVERHEAD WHILE A MOIST
S/SE FLOW IN THE LOW LEVELS CONTINUES. THE MODELS CONTINUE TO DEPICT
AN INCREASINGLY MOIST ATMOSPHERE WITH PWATS RISING INTO THE 1.7-1.8
INCH RANGE AT TIMES...WHICH IS NEAR THE 99TH PERCENTILE AND 2
STANDARD DEVIATIONS ABOVE NORMAL FOR MID/LATE MAY. THE RESULT IS A
QUITE MOIST AND UNCAPPED SCENARIO WHERE SHOWERS/STORMS COULD DEVELOP
AT JUST ABOUT ANY TIME. IN FACT IT WOULDN/T BE SURPRISING IF AT TIME
THE COVERAGE OF PRECIP BECOMES NUMEROUS. THIS WILL LIKELY BE MORE
CLOSELY TIMED WITH THE PASSING OF EMBEDDED ENERGY ALOFT WHICH HAS A
LOW CONFIDENCE AT THIS TIME. POPS HAVE BEEN INCREASED MORE INTO THE
MID/HIGH CHANCE RANGE FOR THE DAYTIME HOURS...WITH EVEN LOW CHANCES
GOING OVERNIGHT. WITH CONSIDERABLE CLOUD COVER AROUND INSOLATION
WILL BE A BIT LIMITED KEEPING HIGHS DOWN A FEW DEGREES...BUT STILL
NEAR OR SLIGHTLY ABOVE NORMAL.

&&

.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
THE UPPER SHORTWAVE NORTH OF THE AREA ON MONDAY WILL ESSENTIALLY
DISSOLVE ACROSS THE EASTERN CAROLINAS ON TUESDAY LEAVING A VERY WEAK
RIDGE PATTERN IN PLACE. ATLANTIC HIGH PRESSURE WILL PRODUCE AN
ONSHORE FLOW WITH SEA BREEZES DEVELOPING EACH AFTERNOON. SURFACE
DEWPOINTS WILL PERSIST IN THE MIDDLE 60S WITH HIGHS CLIMBING WELL
INTO THE 80S EACH DAY. ALTHOUGH THERE ARE NO STRONG FORCING
MECHANISMS...WE KEPT ISOLATED SHOWERS AND THUNDERSTORMS IN THE
FORECAST EACH AFTERNOON/EVENING. A COLD FRONT COULD MOVE INTO THE
AREA ON FRIDAY.

&&

.AVIATION /06Z SATURDAY THROUGH WEDNESDAY/...
VFR CONDITIONS WILL PREVAIL AT KCHS AND KSAV THROUGH 06Z SUNDAY.
ISOLATED CONVECTION COULD DEVELOP LATER THIS AFTERNOON MAINLY
WEST OF THE I-95 CORRIDOR...PROBABILITIES OF ANY CONVECTION
IMPACTING THE TERMINALS ARE TOO LOW TO INCLUDE IN THE FORECAST AT
THIS TIME.

EXTENDED AVIATION OUTLOOK...PRIMARILY VFR. LOW CHANCES OF DIRECT IMPACTS
FROM ISOLATED TO SCATTERED MAINLY AFTERNOON SHOWERS/THUNDERSTORMS
THROUGH EARLY NEXT WEEK.

&&

.MARINE...
OVERNIGHT...QUIET MARINE CONDITIONS WILL PREVAIL AS SURFACE HIGH
PRESSURE EAST OF THE WATERS REMAINS THE DOMINANT WEATHER FEATURE.
GENERALLY EXPECT SOUTH WINDS LESS THAN 15 KT WITH SEAS 2-3
FEET...HIGHEST IN THE OUTER WATERS.

THROUGH EARLY NEXT WEEK...ATLANTIC HIGH PRESSURE WILL BE THE PRIMARY
MARINE INFLUENCE WITH SOUTHERLY FLOW PREVAILING. WIND SPEEDS WILL
PERSIST IN THE 10-15 KT RANGE WITH SEAS 4 FT OR LESS.

&&

.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...NONE.

&&

$$

SYNOPSIS...
NEAR TERM...
SHORT TERM...BSH
LONG TERM...JAQ
AVIATION...
MARINE...

000
FXUS62 KCHS 180206
AFDCHS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
1006 PM EDT FRI MAY 17 2013

.SYNOPSIS...
AN UPPER DISTURBANCE WILL MOVE NORTH OF THE AREA THROUGH THE WEEKEND
AS ATLANTIC HIGH PRESSURE BUILDS ACROSS THE REGION. HIGH PRESSURE
WILL BE THE DOMINANT FEATURE THROUGH MUCH OF NEXT WEEK BEFORE A COLD
FRONT POSSIBLY APPROACHES ON FRIDAY.

&&

.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
ATLANTIC HIGH PRESSURE AT THE SURFACE WILL PREVAIL TONIGHT...AS A
SHORT WAVE TROUGH APPROACHES FROM THE WEST. MID AND HIGH LEVEL
CLOUDS WILL INCREASE IN COVERAGE AND THICKEN SOME OVERNIGHT AS THE
TROUGH NEARS. THE INCREASE IN CLOUDS AND A LIGHT SOUTHERLY FLOW
WILL KEEP LOW TEMPERATURES MAINLY IN THE MID 60S TONIGHT...WITH
UPPER 60S NEAR THE IMMEDIATE COAST.

&&

.SHORT TERM /6 AM SATURDAY MORNING THROUGH MONDAY/...
SATURDAY AND SATURDAY NIGHT...A DEEP AND EXPANSIVE LONGWAVE UPPER
RIDGE WILL ENCOMPASS MUCH OF THE EASTERN HALF OF THE COUNTRY WITH AN
EMBEDDED SHORTWAVE TROUGH POSITIONED NEAR THE OHIO VALLEY. THIS
BAGGY TROUGH CAUGHT WITHIN THE LARGER SCALE RIDGE WILL SLOWLY
MEANDER ACROSS THE APPALACHIANS AND TOWARDS THE EAST COAST. PIECES
OF VORT ENERGY ASSOCIATED WITH THIS FEATURE WILL CROSS THE FORECAST
AREA WITH SOME LOWERING OF HEIGHTS. AT THE SURFACE...THE FORECAST
AREA WILL BE IN THE SOUTHERLY FLOW REGIME AROUND HIGH PRESSURE OVER
THE ATLANTIC. MODEL SOUNDINGS SHOW THE ATMOSPHERE BECOME MORE
CONDUCIVE TO CONVECTIVE DEVELOPMENT IN THE AFTERNOON COMPARED TO
PREVIOUS DAYS...ESPECIALLY ALONG AND WEST OF I-95. AREAS EAST OF
I-95 ARE PROGGED TO SEE WARMER 850 MB TEMPS AND A CAP THAT WILL
LIKELY KEEP DEVELOPMENT ISOLATED AT BEST. FURTHER WEST...THE CAP
ERODES AND WITH COOLING/MOISTENING PROFILES...SCATTERED
SHOWERS/THUNDERSTORMS ARE EXPECTED. THE EXPECTATION IS THAT THIS
WILL BE JUST GARDEN VARIETY SHOWERS/STORMS AS NONE OF THE SEVERE
WEATHER PARAMETERS ARE PARTICULARLY IMPRESSIVE. HIGHS WILL CONTINUE
A FEW DEGREES ABOVE NORMAL REACHING THE MID/UPPER 80S.
OVERNIGHT...ONGOING CONVECTION SHOULD BECOME INCREASINGLY CONFINED
FURTHER WEST AND NORTH AS THE SEABREEZE PUSHES INLAND. I HAVE
MAINTAINED A SMALL AREA OF SLIGHT CHANCES THROUGH THE NIGHT CLOSER
TO THE TROUGH AND BETTER MOISTURE. LOWS WILL BE MILD AND IN THE
MID/UPPER 60S.

SUNDAY THROUGH MONDAY...THIS WILL BE THE MOST ACTIVE TIME PERIOD
WITH THE BEST COVERAGE OF SHOWERS/STORMS. THE BAGGY SHORTWAVE TROUGH
AND ASSOCIATED PASSING VORT MAXES WILL LINGER OVERHEAD WHILE A MOIST
S/SE FLOW IN THE LOW LEVELS CONTINUES. THE MODELS CONTINUE TO DEPICT
AN INCREASINGLY MOIST ATMOSPHERE WITH PWATS RISING INTO THE 1.7-1.8
INCH RANGE AT TIMES...WHICH IS NEAR THE 99TH PERCENTILE AND 2
STANDARD DEVIATIONS ABOVE NORMAL FOR MID/LATE MAY. THE RESULT IS A
QUITE MOIST AND UNCAPPED SCENARIO WHERE SHOWERS/STORMS COULD DEVELOP
AT JUST ABOUT ANY TIME. IN FACT IT WOULDN/T BE SURPRISING IF AT TIME
THE COVERAGE OF PRECIP BECOMES NUMEROUS. THIS WILL LIKELY BE MORE
CLOSELY TIMED WITH THE PASSING OF EMBEDDED ENERGY ALOFT WHICH HAS A
LOW CONFIDENCE AT THIS TIME. POPS HAVE BEEN INCREASED MORE INTO THE
MID/HIGH CHANCE RANGE FOR THE DAYTIME HOURS...WITH EVEN LOW CHANCES
GOING OVERNIGHT. WITH CONSIDERABLE CLOUD COVER AROUND INSOLATION
WILL BE A BIT LIMITED KEEPING HIGHS DOWN A FEW DEGREES...BUT STILL
NEAR OR SLIGHTLY ABOVE NORMAL.

&&

.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
THE UPPER SHORTWAVE NORTH OF THE AREA ON MONDAY WILL ESSENTIALLY
DISSOLVE ACROSS THE EASTERN CAROLINAS ON TUESDAY LEAVING A VERY WEAK
RIDGE PATTERN IN PLACE. ATLANTIC HIGH PRESSURE WILL PRODUCE AN
ONSHORE FLOW WITH SEA BREEZES DEVELOPING EACH AFTERNOON. SURFACE
DEWPOINTS WILL PERSIST IN THE MIDDLE 60S WITH HIGHS CLIMBING WELL
INTO THE 80S EACH DAY. ALTHOUGH THERE ARE NO STRONG FORCING
MECHANISMS...WE KEPT ISOLATED SHOWERS AND THUNDERSTORMS IN THE
FORECAST EACH AFTERNOON/EVENING. A COLD FRONT COULD MOVE INTO THE
AREA ON FRIDAY.

&&

.AVIATION /02Z SATURDAY THROUGH WEDNESDAY/...
VFR CONDITIONS WILL PREVAIL AT KCHS AND KSAV THROUGH 00Z SUNDAY.
ISOLATED/SCATTERED CONVECTION COULD DEVELOP IN THE AFTERNOON
SATURDAY MAINLY ALONG AND WEST OF THE I-95 CORRIDOR...BUT
PROBABILITIES OF ANY CONVECTION IMPACTING THE TERMINALS ARE TOO LOW
TO INCLUDE IN THE FORECAST AT THIS TIME.

EXTENDED AVIATION OUTLOOK...PRIMARILY VFR. LOW CHANCES OF DIRECT IMPACTS
FROM ISOLATED TO SCATTERED MAINLY AFTERNOON SHOWERS/THUNDERSTORMS
THROUGH EARLY NEXT WEEK.

&&

.MARINE...
TONIGHT...QUIET MARINE CONDITIONS WILL PREVAIL AS SURFACE HIGH
PRESSURE EAST OF THE WATERS REMAINS THE DOMINANT WEATHER FEATURE.
GENERALLY EXPECT SOUTH WINDS LESS THAN 15 KTS WITH SEAS 2-3
FEET...HIGHEST IN THE OUTER WATERS.

THROUGH EARLY NEXT WEEK...ATLANTIC HIGH PRESSURE WILL BE THE PRIMARY
MARINE INFLUENCE WITH SOUTHERLY FLOW PREVAILING. WIND SPEEDS WILL
PERSIST IN THE 10-15 KT RANGE WITH SEAS 4 FT OR LESS.

&&

.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...NONE.

&&

$$

SYNOPSIS...
NEAR TERM...JAQ
SHORT TERM...BSH
LONG TERM...JAQ
AVIATION...ECT
MARINE...ECT/BSH

000
FXUS62 KCHS 180020
AFDCHS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
820 PM EDT FRI MAY 17 2013

.SYNOPSIS...
AN UPPER DISTURBANCE WILL MOVE NORTH OF THE AREA THROUGH THE WEEKEND
AS ATLANTIC HIGH PRESSURE BUILDS ACROSS THE REGION. HIGH PRESSURE
WILL BE THE DOMINANT FEATURE THROUGH MUCH OF NEXT WEEK BEFORE A COLD
FRONT POSSIBLY APPROACHES ON FRIDAY.

&&

.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
ATLANTIC HIGH PRESSURE AT THE SURFACE WILL PREVAIL TONIGHT...AS A
SHORT WAVE TROUGH APPROACHES FROM THE WEST. MID AND HIGH LEVEL
CLOUDS WILL INCREASE IN COVERAGE AND THICKEN SOME OVERNIGHT AS THE
TROUGH NEARS. THE INCREASE IN CLOUDS AND A LIGHT SOUTHERLY FLOW
WILL KEEP LOW TEMPERATURES MAINLY IN THE MID 60S TONIGHT...WITH
UPPER 60S NEAR THE IMMEDIATE COAST.

&&

.SHORT TERM /6 AM SATURDAY MORNING THROUGH MONDAY/...
SATURDAY AND SATURDAY NIGHT...A DEEP AND EXPANSIVE LONGWAVE UPPER
RIDGE WILL ENCOMPASS MUCH OF THE EASTERN HALF OF THE COUNTRY WITH AN
EMBEDDED SHORTWAVE TROUGH POSITIONED NEAR THE OHIO VALLEY. THIS
BAGGY TROUGH CAUGHT WITHIN THE LARGER SCALE RIDGE WILL SLOWLY
MEANDER ACROSS THE APPALACHIANS AND TOWARDS THE EAST COAST. PIECES
OF VORT ENERGY ASSOCIATED WITH THIS FEATURE WILL CROSS THE FORECAST
AREA WITH SOME LOWERING OF HEIGHTS. AT THE SURFACE...THE FORECAST
AREA WILL BE IN THE SOUTHERLY FLOW REGIME AROUND HIGH PRESSURE OVER
THE ATLANTIC. MODEL SOUNDINGS SHOW THE ATMOSPHERE BECOME MORE
CONDUCIVE TO CONVECTIVE DEVELOPMENT IN THE AFTERNOON COMPARED TO
PREVIOUS DAYS...ESPECIALLY ALONG AND WEST OF I-95. AREAS EAST OF
I-95 ARE PROGGED TO SEE WARMER 850 MB TEMPS AND A CAP THAT WILL
LIKELY KEEP DEVELOPMENT ISOLATED AT BEST. FURTHER WEST...THE CAP
ERODES AND WITH COOLING/MOISTENING PROFILES...SCATTERED
SHOWERS/THUNDERSTORMS ARE EXPECTED. THE EXPECTATION IS THAT THIS
WILL BE JUST GARDEN VARIETY SHOWERS/STORMS AS NONE OF THE SEVERE
WEATHER PARAMETERS ARE PARTICULARLY IMPRESSIVE. HIGHS WILL CONTINUE
A FEW DEGREES ABOVE NORMAL REACHING THE MID/UPPER 80S.
OVERNIGHT...ONGOING CONVECTION SHOULD BECOME INCREASINGLY CONFINED
FURTHER WEST AND NORTH AS THE SEABREEZE PUSHES INLAND. I HAVE
MAINTAINED A SMALL AREA OF SLIGHT CHANCES THROUGH THE NIGHT CLOSER
TO THE TROUGH AND BETTER MOISTURE. LOWS WILL BE MILD AND IN THE
MID/UPPER 60S.

SUNDAY THROUGH MONDAY...THIS WILL BE THE MOST ACTIVE TIME PERIOD
WITH THE BEST COVERAGE OF SHOWERS/STORMS. THE BAGGY SHORTWAVE TROUGH
AND ASSOCIATED PASSING VORT MAXES WILL LINGER OVERHEAD WHILE A MOIST
S/SE FLOW IN THE LOW LEVELS CONTINUES. THE MODELS CONTINUE TO DEPICT
AN INCREASINGLY MOIST ATMOSPHERE WITH PWATS RISING INTO THE 1.7-1.8
INCH RANGE AT TIMES...WHICH IS NEAR THE 99TH PERCENTILE AND 2
STANDARD DEVIATIONS ABOVE NORMAL FOR MID/LATE MAY. THE RESULT IS A
QUITE MOIST AND UNCAPPED SCENARIO WHERE SHOWERS/STORMS COULD DEVELOP
AT JUST ABOUT ANY TIME. IN FACT IT WOULDN/T BE SURPRISING IF AT TIME
THE COVERAGE OF PRECIP BECOMES NUMEROUS. THIS WILL LIKELY BE MORE
CLOSELY TIMED WITH THE PASSING OF EMBEDDED ENERGY ALOFT WHICH HAS A
LOW CONFIDENCE AT THIS TIME. POPS HAVE BEEN INCREASED MORE INTO THE
MID/HIGH CHANCE RANGE FOR THE DAYTIME HOURS...WITH EVEN LOW CHANCES
GOING OVERNIGHT. WITH CONSIDERABLE CLOUD COVER AROUND INSOLATION
WILL BE A BIT LIMITED KEEPING HIGHS DOWN A FEW DEGREES...BUT STILL
NEAR OR SLIGHTLY ABOVE NORMAL.

&&

.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
THE UPPER SHORTWAVE NORTH OF THE AREA ON MONDAY WILL ESSENTIALLY
DISSOLVE ACROSS THE EASTERN CAROLINAS ON TUESDAY LEAVING A VERY WEAK
RIDGE PATTERN IN PLACE. ATLANTIC HIGH PRESSURE WILL PRODUCE AN
ONSHORE FLOW WITH SEA BREEZES DEVELOPING EACH AFTERNOON. SURFACE
DEWPOINTS WILL PERSIST IN THE MIDDLE 60S WITH HIGHS CLIMBING WELL
INTO THE 80S EACH DAY. ALTHOUGH THERE ARE NO STRONG FORCING
MECHANISMS...WE KEPT ISOLATED SHOWERS AND THUNDERSTORMS IN THE
FORECAST EACH AFTERNOON/EVENING. A COLD FRONT COULD MOVE INTO THE
AREA ON FRIDAY.

&&

.AVIATION /00Z SATURDAY THROUGH WEDNESDAY/...
VFR CONDITIONS WILL PREVAIL AT KCHS AND KSAV THROUGH 00Z SUNDAY.
ISOLATED/SCATTERED CONVECTION COULD DEVELOP IN THE AFTERNOON
SATURDAY MAINLY ALONG AND WEST OF THE I-95 CORRIDOR...BUT
PROBABILITIES OF ANY CONVECTION IMPACTING THE TERMINALS ARE TOO LOW
TO INCLUDE IN THE FORECAST AT THIS TIME.

EXTENDED AVIATION OUTLOOK...PRIMARILY VFR. LOW CHANCES OF DIRECT IMPACTS
FROM ISOLATED TO SCATTERED MAINLY AFTERNOON SHOWERS/THUNDERSTORMS
THROUGH EARLY NEXT WEEK.

&&

.MARINE...
TONIGHT...QUIET MARINE CONDITIONS WILL PREVAIL AS SURFACE HIGH
PRESSURE EAST OF THE WATERS REMAINS THE DOMINANT WEATHER FEATURE.
GENERALLY EXPECT SOUTH WINDS LESS THAN 15 KTS WITH SEAS 2-3
FEET...HIGHEST IN THE OUTER WATERS.

THROUGH EARLY NEXT WEEK...ATLANTIC HIGH PRESSURE WILL BE THE PRIMARY
MARINE INFLUENCE WITH SOUTHERLY FLOW PREVAILING. WIND SPEEDS WILL
PERSIST IN THE 10-15 KT RANGE WITH SEAS 4 FT OR LESS.

&&

.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...NONE.

&&

$$

SYNOPSIS...
NEAR TERM...JAQ
SHORT TERM...BSH
LONG TERM...JAQ
AVIATION...ECT
MARINE...BSH/ECT

000
FXUS62 KCHS 171953
AFDCHS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
353 PM EDT FRI MAY 17 2013

.SYNOPSIS...
AN UPPER DISTURBANCE WILL MOVE NORTH OF THE AREA THROUGH THE WEEKEND
AS ATLANTIC HIGH PRESSURE BUILDS ACROSS THE REGION. HIGH PRESSURE
WILL BE THE DOMINANT FEATURE THROUGH MUCH OF NEXT WEEK BEFORE A COLD
FRONT POSSIBLY APPROACHES ON FRIDAY.

&&

.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
QUIET WEATHER EXPECTED THROUGH THE OVERNIGHT PERIOD AS THE FORECAST
AREA REMAINS UNDER THE INFLUENCE OF ATLANTIC HIGH PRESSURE.
VORT ENERGY...ASSOCIATED WITH A SHORTWAVE TROUGH APPROACHING FROM
THE WEST...WILL KEEP SOME MID AND HIGH CLOUDS AROUND THROUGH THE
NIGHT. THIS WILL MODERATE TEMPERATURES AND ALLOW FOR LOWS TO BE A
COUPLE DEGREES ABOVE NORMAL. MIN TEMPERATURES ARE EXPECTED TO BE
MAINLY IN THE MIDDLE 60S...WITH UPPER 60S CLOSER TO THE COAST.

&&

.SHORT TERM /6 AM SATURDAY MORNING THROUGH MONDAY/...
SATURDAY AND SATURDAY NIGHT...A DEEP AND EXPANSIVE LONGWAVE UPPER
RIDGE WILL ENCOMPASS MUCH OF THE EASTERN HALF OF THE COUNTRY WITH AN
EMBEDDED SHORTWAVE TROUGH POSITIONED NEAR THE OHIO VALLEY. THIS
BAGGY TROUGH CAUGHT WITHIN THE LARGER SCALE RIDGE WILL SLOWLY
MEANDER ACROSS THE APPALACHIANS AND TOWARDS THE EAST COAST. PIECES
OF VORT ENERGY ASSOCIATED WITH THIS FEATURE WILL CROSS THE FORECAST
AREA WITH SOME LOWERING OF HEIGHTS. AT THE SURFACE...THE FORECAST
AREA WILL BE IN THE SOUTHERLY FLOW REGIME AROUND HIGH PRESSURE OVER
THE ATLANTIC. MODEL SOUNDINGS SHOW THE ATMOSPHERE BECOME MORE
CONDUCIVE TO CONVECTIVE DEVELOPMENT IN THE AFTERNOON COMPARED TO
PREVIOUS DAYS...ESPECIALLY ALONG AND WEST OF I-95. AREAS EAST OF
I-95 ARE PROGGED TO SEE WARMER 850 MB TEMPS AND A CAP THAT WILL
LIKELY KEEP DEVELOPMENT ISOLATED AT BEST. FURTHER WEST...THE CAP
ERODES AND WITH COOLING/MOISTENING PROFILES...SCATTERED
SHOWERS/THUNDERSTORMS ARE EXPECTED. THE EXPECTATION IS THAT THIS
WILL BE JUST GARDEN VARIETY SHOWERS/STORMS AS NONE OF THE SEVERE
WEATHER PARAMETERS ARE PARTICULARLY IMPRESSIVE. HIGHS WILL CONTINUE
A FEW DEGREES ABOVE NORMAL REACHING THE MID/UPPER 80S.
OVERNIGHT...ONGOING CONVECTION SHOULD BECOME INCREASINGLY CONFINED
FURTHER WEST AND NORTH AS THE SEABREEZE PUSHES INLAND. I HAVE
MAINTAINED A SMALL AREA OF SLIGHT CHANCES THROUGH THE NIGHT CLOSER
TO THE TROUGH AND BETTER MOISTURE. LOWS WILL BE MILD AND IN THE
MID/UPPER 60S.

SUNDAY THROUGH MONDAY...THIS WILL BE THE MOST ACTIVE TIME PERIOD
WITH THE BEST COVERAGE OF SHOWERS/STORMS. THE BAGGY SHORTWAVE TROUGH
AND ASSOCIATED PASSING VORT MAXES WILL LINGER OVERHEAD WHILE A MOIST
S/SE FLOW IN THE LOW LEVELS CONTINUES. THE MODELS CONTINUE TO DEPICT
AN INCREASINGLY MOIST ATMOSPHERE WITH PWATS RISING INTO THE 1.7-1.8
INCH RANGE AT TIMES...WHICH IS NEAR THE 99TH PERCENTILE AND 2
STANDARD DEVIATIONS ABOVE NORMAL FOR MID/LATE MAY. THE RESULT IS A
QUITE MOIST AND UNCAPPED SCENARIO WHERE SHOWERS/STORMS COULD DEVELOP
AT JUST ABOUT ANY TIME. IN FACT IT WOULDN/T BE SURPRISING IF AT TIME
THE COVERAGE OF PRECIP BECOMES NUMEROUS. THIS WILL LIKELY BE MORE
CLOSELY TIMED WITH THE PASSING OF EMBEDDED ENERGY ALOFT WHICH HAS A
LOW CONFIDENCE AT THIS TIME. POPS HAVE BEEN INCREASED MORE INTO THE
MID/HIGH CHANCE RANGE FOR THE DAYTIME HOURS...WITH EVEN LOW CHANCES
GOING OVERNIGHT. WITH CONSIDERABLE CLOUD COVER AROUND INSOLATION
WILL BE A BIT LIMITED KEEPING HIGHS DOWN A FEW DEGREES...BUT STILL
NEAR OR SLIGHTLY ABOVE NORMAL.

&&

.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
THE UPPER SHORTWAVE NORTH OF THE AREA ON MONDAY WILL ESSENTIALLY
DISSOLVE ACROSS THE EASTERN CAROLINAS ON TUESDAY LEAVING A VERY WEAK
RIDGE PATTERN IN PLACE. ATLANTIC HIGH PRESSURE WILL PRODUCE AN
ONSHORE FLOW WITH SEA BREEZES DEVELOPING EACH AFTERNOON. SURFACE
DEWPOINTS WILL PERSIST IN THE MIDDLE 60S WITH HIGHS CLIMBING WELL
INTO THE 80S EACH DAY. ALTHOUGH THERE ARE NO STRONG FORCING
MECHANISMS...WE KEPT ISOLATED SHOWERS AND THUNDERSTORMS IN THE
FORECAST EACH AFTERNOON/EVENING. A COLD FRONT COULD MOVE INTO THE
AREA ON FRIDAY.

&&

.AVIATION /20Z FRIDAY THROUGH WEDNESDAY/...
VFR IS EXPECTED TO PREVAIL AT KCHS AND KSAV THROUGH 18Z SATURDAY.

EXTENDED AVIATION OUTLOOK...PRIMARILY VFR. LOW CHANCES OF DIRECT IMPACTS
FROM ISOLATED TO SCATTERED MAINLY AFTERNOON SHOWERS/THUNDERSTORMS
THROUGH EARLY NEXT WEEK.

&&

.MARINE...
OVERNIGHT...QUIET MARINE CONDITIONS WILL PREVAIL AS SURFACE HIGH
PRESSURE EAST OF THE WATERS REMAINS THE DOMINANT WEATHER FEATURE.
GENERALLY EXPECT SOUTH WINDS LESS THAN 15 KTS WITH SEAS 2-3
FEET...HIGHEST IN THE OUTER WATERS.

THROUGH EARLY NEXT WEEK...ATLANTIC HIGH PRESSURE WILL BE THE PRIMARY
MARINE INFLUENCE WITH SOUTHERLY FLOW PREVAILING. WIND SPEEDS WILL
PERSIST IN THE 10-15 KT RANGE WITH SEAS 4 FT OR LESS.

&&

.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...NONE.

&&

$$

SYNOPSIS...
NEAR TERM...ECT
SHORT TERM...BSH
LONG TERM...JRL
AVIATION...ECT
MARINE...BSH/ECT

000
FXUS62 KCHS 171717
AFDCHS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
117 PM EDT FRI MAY 17 2013

.SYNOPSIS...
AN UPPER DISTURBANCE WILL MOVE NORTH OF THE AREA THROUGH THE WEEKEND
AS ATLANTIC HIGH PRESSURE BUILDS ACROSS THE REGION. HIGH PRESSURE
WILL BE THE DOMINANT FEATURE THROUGH MUCH OF NEXT WEEK BEFORE A COLD
FRONT POSSIBLY APPROACHES ON FRIDAY.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
ATLANTIC HIGH PRESSURE WILL ONCE AGAIN REMAIN THE DOMINANT WEATHER
FEATURE TODAY. MAIN FORECAST ISSUE WILL REVOLVE AROUND POTENTIAL
PRECIP THIS AFTERNOON. SOME MODELS STILL HINT THAT ACTIVITY COULD
FIRE OFF THE INLAND PENETRATING SEA BREEZE THIS AFTERNOON. HAVE
MAINTAINED LOW END SLIGHT CHANCES WEST OF I-95 AS COVERAGE...IF
ANY...WILL BE VERY ISOLATED. OTHERWISE...EXPECT ANOTHER PLEASANT
DAY WITH HIGHS REACHING THE MID AND UPPER 80S. NO MAJOR CHANGES
WERE NEEDED WITH THIS UPDATE.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH MONDAY/...
DRY WEATHER ANTICIPATED TONIGHT WITH A SHORT WAVE RIDGE BUILDING
ACROSS GEORGIA AND THE CAROLINAS. OCCASIONAL MID/HIGH CLOUDS WILL
PASS THROUGH THE REGION WITH LOWS IN THE 60S...SIMILAR TO READINGS
ON FRI MORNING.

AN UPPER SHORTWAVE WILL DRIFT SOUTHEAST FROM THE OHIO VALLEY INTO
NORTH CAROLINA SATURDAY THROUGH MONDAY. ALTHOUGH THE BRUNT OF THE
VORTICITY WILL STAY NORTH OF THE FORECAST AREA...THE UPPER HEIGHT
FALLS WILL PRODUCE A MORE FAVORABLE ENVIRONMENT FOR SHOWERS AND
THUNDERSTORMS. LOW-LEVEL MOISTURE WILL INCREASE SUBSTANTIALLY SUNDAY
INTO MONDAY WHEN THE UPPER VORT MAKES ITS CLOSEST APPROACH. ON
SATURDAY THE SEABREEZE SHOULD BE THE PRIMARY DRIVER FOR CONVECTION.
SUNDAY INTO MONDAY THE COVERAGE SHOULD BE A BIT GREATER AS
MID-LEVELS COOL SLIGHTLY IN CONCERT WITH INCREASING LOW-LEVEL
MOISTURE. WE HAVE 30-40 POPS BOTH DAYS...WITH SLIGHT CHANCES DURING
THE OVERNIGHT HOURS. HIGH TEMPS WILL BE SOLIDLY IN THE 80S WITH LOWS
IN THE 60S.

&&

.LONG TERM /MONDAY NIGHT THROUGH THURSDAY/...
THE UPPER SHORTWAVE NORTH OF THE AREA ON MONDAY WILL ESSENTIALLY
DISSOLVE ACROSS THE EASTERN CAROLINAS ON TUESDAY LEAVING A VERY WEAK
RIDGE PATTERN IN PLACE. ATLANTIC HIGH PRESSURE WILL PRODUCE AN
ONSHORE FLOW WITH SEA BREEZES DEVELOPING EACH AFTERNOON. SURFACE
DEWPOINTS WILL PERSIST IN THE MIDDLE 60S WITH HIGHS CLIMBING WELL
INTO THE 80S EACH DAY. ALTHOUGH THERE ARE NO STRONG FORCING
MECHANISMS...WE KEPT ISOLATED SHOWERS AND THUNDERSTORMS IN THE
FORECAST EACH AFTERNOON/EVENING. A COLD FRONT COULD MOVE INTO THE
AREA ON FRIDAY.

&&

.AVIATION /18Z FRIDAY THROUGH WEDNESDAY/...
VFR IS EXPECTED TO PREVAIL AT KCHS AND KSAV THROUGH 18Z SATURDAY.

EXTENDED AVIATION OUTLOOK...PRIMARILY VFR. ISOLATED TO SCATTERED
AFTERNOON SHOWERS/THUNDERSTORMS EXPECTED EACH AFTERNOON THROUGH
EARLY NEXT WEEK.

&&

.MARINE...
THROUGH TONIGHT...THE LOW LEVEL RIDGE AXIS REMAINS CONSTANT AND
SO DOES OUR FORECAST WITH A SOUTHERLY COMPONENT LESS THAN 15 KT
AND SEAS 3 FT OR LESS. DIRECTIONS SHOULD BACK A BIT MORE SE ALONG
THE GEORGIA COAST THIS AFTERNOON AS THE LAND WARMS AND THE SEA
BREEZE PUSHES INLAND.

ATLANTIC HIGH PRESSURE WILL BE THE PRIMARY MARINE INFLUENCE THROUGH
THE PERIOD WITH SOUTHERLY FLOW PREVAILING. WIND SPEEDS WILL PERSIST
IN THE 10-15 KT RANGE WITH SEAS 4 FT OR LESS.

&&

.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...NONE.

&&

$$

SYNOPSIS...
NEAR TERM...ECT
SHORT TERM...JRL
LONG TERM...JRL
AVIATION...ECT
MARINE...ECT/JRL

000
FXUS62 KCHS 171417
AFDCHS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
1017 AM EDT FRI MAY 17 2013

.SYNOPSIS...
AN UPPER DISTURBANCE WILL MOVE NORTH OF THE AREA THROUGH THE WEEKEND
AS ATLANTIC HIGH PRESSURE BUILDS ACROSS THE REGION. HIGH PRESSURE
WILL BE THE DOMINANT FEATURE THROUGH MUCH OF NEXT WEEK BEFORE A COLD
FRONT POSSIBLY APPROACHES ON FRIDAY.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
ATLANTIC HIGH PRESSURE WILL ONCE AGAIN REMAIN THE DOMINANT WEATHER
FEATURE TODAY. MAIN FORECAST ISSUE WILL REVOLVE AROUND POTENTIAL
PRECIP THIS AFTERNOON. MODELS ARE A BIT SCATTERED ON SHOWING
DEVELOPMENT...WITH MOST NOT SHOWING MUCH OVER OUR FORECAST AREA. HAVE
MAINTAINED LOW END SLIGHT CHANCES WEST OF I-95 AS COVERAGE...IF
ANY...WILL BE VERY ISOLATED. OVERALL...PARAMETERS ARE NOT THAT
FAVORABLE FOR DEEP MOIST CONVECTION...AS SHEAR IS WEAK AND
FORECAST SOUNDINGS ARE PRETTY DRY.

OTHERWISE...EXPECT ANOTHER PLEASANT DAY. SHOULD SEE MORE SUNSHINE
AND WARMER TEMPERATURES THAN THURSDAY...WITH HIGHS IN THE MID AND
UPPER 80S. NO MAJOR CHANGES WERE NEEDED WITH THIS UPDATE.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH MONDAY/...
DRY WEATHER ANTICIPATED TONIGHT WITH A SHORT WAVE RIDGE BUILDING
ACROSS GEORGIA AND THE CAROLINAS. OCCASIONAL MID/HIGH CLOUDS WILL
PASS THROUGH THE REGION WITH LOWS IN THE 60S...SIMILAR TO READINGS
ON FRI MORNING.

AN UPPER SHORTWAVE WILL DRIFT SOUTHEAST FROM THE OHIO VALLEY INTO
NORTH CAROLINA SATURDAY THROUGH MONDAY. ALTHOUGH THE BRUNT OF THE
VORTICITY WILL STAY NORTH OF THE FORECAST AREA...THE UPPER HEIGHT
FALLS WILL PRODUCE A MORE FAVORABLE ENVIRONMENT FOR SHOWERS AND
THUNDERSTORMS. LOW-LEVEL MOISTURE WILL INCREASE SUBSTANTIALLY SUNDAY
INTO MONDAY WHEN THE UPPER VORT MAKES ITS CLOSEST APPROACH. ON
SATURDAY THE SEABREEZE SHOULD BE THE PRIMARY DRIVER FOR CONVECTION.
SUNDAY INTO MONDAY THE COVERAGE SHOULD BE A BIT GREATER AS
MID-LEVELS COOL SLIGHTLY IN CONCERT WITH INCREASING LOW-LEVEL
MOISTURE. WE HAVE 30-40 POPS BOTH DAYS...WITH SLIGHT CHANCES DURING
THE OVERNIGHT HOURS. HIGH TEMPS WILL BE SOLIDLY IN THE 80S WITH LOWS
IN THE 60S.

&&

.LONG TERM /MONDAY NIGHT THROUGH THURSDAY/...
THE UPPER SHORTWAVE NORTH OF THE AREA ON MONDAY WILL ESSENTIALLY
DISSOLVE ACROSS THE EASTERN CAROLINAS ON TUESDAY LEAVING A VERY WEAK
RIDGE PATTERN IN PLACE. ATLANTIC HIGH PRESSURE WILL PRODUCE AN
ONSHORE FLOW WITH SEA BREEZES DEVELOPING EACH AFTERNOON. SURFACE
DEWPOINTS WILL PERSIST IN THE MIDDLE 60S WITH HIGHS CLIMBING WELL
INTO THE 80S EACH DAY. ALTHOUGH THERE ARE NO STRONG FORCING
MECHANISMS...WE KEPT ISOLATED SHOWERS AND THUNDERSTORMS IN THE
FORECAST EACH AFTERNOON/EVENING. A COLD FRONT COULD MOVE INTO THE
AREA ON FRIDAY.

&&

.AVIATION /14Z FRIDAY THROUGH TUESDAY/...
VFR CONDITIONS WILL PREVAIL AT KCHS AND KSAV THROUGH 12Z SATURDAY.

EXTENDED AVIATION OUTLOOK...PRIMARILY VFR. ISOLATED TO SCATTERED
AFTERNOON SHOWERS/THUNDERSTORMS EXPECTED EACH AFTERNOON THROUGH
EARLY NEXT WEEK.

&&

.MARINE...
THROUGH TONIGHT...THE LOW LEVEL RIDGE AXIS REMAINS CONSTANT AND
SO DOES OUR FORECAST WITH A SOUTHERLY COMPONENT LESS THAN 15 KT
AND SEAS 3 FT OR LESS. DIRECTIONS SHOULD BACK A BIT MORE SE ALONG
THE GEORGIA COAST THIS AFTERNOON AS THE LAND WARMS AND THE SEA
BREEZE PUSHES INLAND.

ATLANTIC HIGH PRESSURE WILL BE THE PRIMARY MARINE INFLUENCE THROUGH
THE PERIOD WITH SOUTHERLY FLOW PREVAILING. WIND SPEEDS WILL PERSIST
IN THE 10-15 KT RANGE WITH SEAS 4 FT OR LESS.

&&

.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...NONE.

&&

$$

SYNOPSIS...
NEAR TERM...ECT
SHORT TERM...JRL
LONG TERM...JRL
AVIATION...ECT
MARINE...ECT/JRL

000
FXUS62 KCHS 171118
AFDCHS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
718 AM EDT FRI MAY 17 2013

.SYNOPSIS...
AN UPPER DISTURBANCE WILL MOVE NORTH OF THE AREA THROUGH THE WEEKEND
AS ATLANTIC HIGH PRESSURE BUILDS ACROSS THE REGION. HIGH PRESSURE
WILL BE THE DOMINANT FEATURE THROUGH MUCH OF NEXT WEEK BEFORE A COLD
FRONT POSSIBLY APPROACHES ON FRIDAY.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
THE MOST NOTABLE FEATURE ON WATER VAPOR SATELLITE IMAGERY IS THE
SLOW MOVING CUT-OFF MID LEVEL LOW OVER THE MID SOUTH REGION. THIS
FEATURE IS FORECAST TO OPEN UP AND LIFT ENE INTO THE TENNESSEE
VALLEY REGION WELL TO OUR NW. A WEAK MID LEVEL SHORT WAVE IS
EXPECTED TO RIPPLE THROUGH GEORGIA TODAY BUT IN THE LOW LEVELS THE
EXPANSIVE ATLC RIDGE REMAINS IN CONTROL.

MODELS ARE SPLIT ON WHETHER ISOLATED LATE DAY CONVECTION WILL INITIATE
TO THE W OF I-95 TODAY. GLANCES AT MODIFIED PROXIMITY NAM/GFS SOUNDINGS
AT KOGB-KAGS-KAYS INDICATE PRETTY POOR VERTICAL PROFILES FOR DEEP
CONVECTION POTENTIAL. THERE IS SOME MID LEVEL INSTABILITY NOTED...LIKELY
TO BE NEGATED BY ANY FOCUS IN LOW LEVEL THETA-E ADVECTION AND MARGINAL
SURFACE DEW POINTS. WE HELD ONTO 15-17 PERCENT POPS MAINLY W OF I-95
PER PERSISTENCE AND VARIOUS HIGH RESOLUTION GUIDANCE TRENDS. WE ARE
NOT LOOKING FOR MUCH IN THE WAY OF DEEP OR SUBSTANTIAL CONVECTION...
PERHAPS A FEW SPOTTY CELLS ALONG THE LATE AFTERNOON SEA BREEZE
INTRUSION. NO RAIN EXPECTED IN EITHER CHARLESTON OR SAVANNAH.

MODEL CLOUD PROGS AND SOUNDINGS INDICATE WE WILL SEE MORE SUNSHINE
TODAY AND HIGHS BETWEEN 85 AND 90 DEGREES ARE LIKELY. SURFACE WINDS
MOSTLY LIGHT TODAY OUTSIDE OF ANY SEA BREEZE OSCILLATION EFFECTS
NEAR THE COAST.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH MONDAY/...
DRY WEATHER ANTICIPATED TONIGHT WITH A SHORT WAVE RIDGE BUILDING
ACROSS GEORGIA AND THE CAROLINAS. OCCASIONAL MID/HIGH CLOUDS WILL
PASS THROUGH THE REGION WITH LOWS IN THE 60S...SIMILAR TO READINGS
ON FRI MORNING.

AN UPPER SHORTWAVE WILL DRIFT SOUTHEAST FROM THE OHIO VALLEY INTO
NORTH CAROLINA SATURDAY THROUGH MONDAY. ALTHOUGH THE BRUNT OF THE
VORTICITY WILL STAY NORTH OF THE FORECAST AREA...THE UPPER HEIGHT
FALLS WILL PRODUCE A MORE FAVORABLE ENVIRONMENT FOR SHOWERS AND
THUNDERSTORMS. LOW-LEVEL MOISTURE WILL INCREASE SUBSTANTIALLY SUNDAY
INTO MONDAY WHEN THE UPPER VORT MAKES ITS CLOSEST APPROACH. ON
SATURDAY THE SEABREEZE SHOULD BE THE PRIMARY DRIVER FOR CONVECTION.
SUNDAY INTO MONDAY THE COVERAGE SHOULD BE A BIT GREATER AS
MID-LEVELS COOL SLIGHTLY IN CONCERT WITH INCREASING LOW-LEVEL
MOISTURE. WE HAVE 30-40 POPS BOTH DAYS...WITH SLIGHT CHANCES DURING
THE OVERNIGHT HOURS. HIGH TEMPS WILL BE SOLIDLY IN THE 80S WITH LOWS
IN THE 60S.

&&

.LONG TERM /MONDAY NIGHT THROUGH THURSDAY/...
THE UPPER SHORTWAVE NORTH OF THE AREA ON MONDAY WILL ESSENTIALLY
DISSOLVE ACROSS THE EASTERN CAROLINAS ON TUESDAY LEAVING A VERY WEAK
RIDGE PATTERN IN PLACE. ATLANTIC HIGH PRESSURE WILL PRODUCE AN
ONSHORE FLOW WITH SEA BREEZES DEVELOPING EACH AFTERNOON. SURFACE
DEWPOINTS WILL PERSIST IN THE MIDDLE 60S WITH HIGHS CLIMBING WELL
INTO THE 80S EACH DAY. ALTHOUGH THERE ARE NO STRONG FORCING
MECHANISMS...WE KEPT ISOLATED SHOWERS AND THUNDERSTORMS IN THE
FORECAST EACH AFTERNOON/EVENING. A COLD FRONT COULD MOVE INTO THE
AREA ON FRIDAY.

&&

.AVIATION /11Z FRIDAY THROUGH TUESDAY/...
VFR CONDITIONS WILL PREVAIL AT KCHS AND KSAV THROUGH 12Z SATURDAY.

EXTENDED AVIATION OUTLOOK...PRIMARILY VFR. ISOLATED TO SCATTERED
AFTERNOON SHOWERS/THUNDERSTORMS EXPECTED EACH AFTERNOON THROUGH
EARLY NEXT WEEK.

&&

.MARINE...
THROUGH TONIGHT...THE LOW LEVEL RIDGE AXIS REMAINS CONSTANT AND
SO DOES OUR FORECAST WITH A SOUTHERLY COMPONENT LESS THAN 15 KT
AND SEAS 3 FT OR LESS. DIRECTIONS SHOULD BACK A BIT MORE SE ALONG
THE GEORGIA COAST THIS AFTERNOON AS THE LAND WARMS AND THE SEA
BREEZE PUSHES INLAND.

ATLANTIC HIGH PRESSURE WILL BE THE PRIMARY MARINE INFLUENCE THROUGH
THE PERIOD WITH SOUTHERLY FLOW PREVAILING. WIND SPEEDS WILL PERSIST
IN THE 10-15 KT RANGE WITH SEAS 4 FT OR LESS.

&&

.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...NONE.

&&

$$

SYNOPSIS...
NEAR TERM...
SHORT TERM...JRL
LONG TERM...JRL
AVIATION...
MARINE...JRL

000
FXUS62 KCHS 170812
AFDCHS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
412 AM EDT FRI MAY 17 2013

.SYNOPSIS...
AN UPPER DISTURBANCE WILL MOVE NORTH OF THE AREA THROUGH THE WEEKEND
AS ATLANTIC HIGH PRESSURE BUILDS ACROSS THE REGION. HIGH PRESSURE
WILL BE THE DOMINANT FEATURE THROUGH MUCH OF NEXT WEEK BEFORE A COLD
FRONT POSSIBLY APPROACHES ON FRIDAY.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
PRE-DAWN...IT HAS BEEN A MILD AND MORE HUMID OVERNIGHT ACROSS THE
REGION AS SURFACE TEMPS AND DEW POINTS BOTH SOLIDLY UP IN THE 60S.
THE LOW LEVEL RIDGE AXIS CONTINUES TO POKE INTO N FLORIDA AND FAR
S GEORGIA WITH A WEAK PRES PATTERN FOR THE AREA. OVERNIGHT WE HAVE
SEEN PERIODS OF HIGH CLOUDS AT TIMES...OTHERWISE IT HAS BEEN MOSTLY
CLEAR.

TODAY...THE MOST NOTABLE FEATURE ON WATER VAPOR SATELLITE IMAGERY
IS THE SLOW MOVING CUT-OFF MID LEVEL LOW OVER THE MID SOUTH REGION.
THIS FEATURE IS FORECAST TO OPEN UP AND LIFT ENE INTO THE TENNESSEE
VALLEY REGION WELL TO OUR NW. A WEAK MID LEVEL SHORT WAVE IS
EXPECTED TO RIPPLE THROUGH GEORGIA TODAY BUT IN THE LOW LEVELS THE
ATLC RIDGE REMAINS IN CONTROL.

MODELS ARE SPLIT ON WHETHER ISOLATED LATE DAY CONVECTION WILL INITIATE
TO THE W OF I-95 TODAY. GLANCES AT MODIFIED PROXIMITY NAM/GFS SOUNDINGS
AT KOGB-KAGS-KAYS INDICATE PRETTY POOR VERTICAL PROFILES FOR DEEP
CONVECTION POTENTIAL. THERE IS SOME MID LEVEL INSTABILITY NOTED...LIKELY
TO BE NEGATED BY ANY FOCUS IN LOW LEVEL THETA-E ADVECTION AND MARGINAL
SURFACE DEW POINTS. WE HELD ONTO 15-17 PERCENT POPS MAINLY W OF I-95
PER PERSISTENCE AND VARIOUS HIGH RESOLUTION GUIDANCE TRENDS. WE ARE
NOT LOOKING FOR MUCH IN THE WAY OF DEEP OR SUBSTANTIAL CONVECTION...
PERHAPS A FEW SPOTTY CELLS ALONG THE LATE AFTERNOON SEA BREEZE
INTRUSION. NO RAIN EXPECTED IN EITHER CHARLESTON OR SAVANNAH.

MODEL CLOUD PROGS AND SOUNDINGS INDICATE WE WILL SEE MORE SUNSHINE
TODAY AND HIGHS BETWEEN 85 AND 90 DEGREES ARE LIKELY. SURFACE WINDS
MOSTLY LIGHT TODAY OUTSIDE OF ANY SEA BREEZE OSCILLATION EFFECTS
NEAR THE COAST.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH MONDAY/...
DRY WEATHER ANTICIPATED TONIGHT WITH A SHORT WAVE RIDGE BUILDING
ACROSS GEORGIA AND THE CAROLINAS. OCCASIONAL MID/HIGH CLOUDS WILL
PASS THROUGH THE REGION WITH LOWS IN THE 60S...SIMILAR TO READINGS
ON FRI MORNING.

AN UPPER SHORTWAVE WILL DRIFT SOUTHEAST FROM THE OHIO VALLEY INTO
NORTH CAROLINA SATURDAY THROUGH MONDAY. ALTHOUGH THE BRUNT OF THE
VORTICITY WILL STAY NORTH OF THE FORECAST AREA...THE UPPER HEIGHT
FALLS WILL PRODUCE A MORE FAVORABLE ENVIRONMENT FOR SHOWERS AND
THUNDERSTORMS. LOW-LEVEL MOISTURE WILL INCREASE SUBSTANTIALLY SUNDAY
INTO MONDAY WHEN THE UPPER VORT MAKES ITS CLOSEST APPROACH. ON
SATURDAY THE SEABREEZE SHOULD BE THE PRIMARY DRIVER FOR CONVECTION.
SUNDAY INTO MONDAY THE COVERAGE SHOULD BE A BIT GREATER AS
MID-LEVELS COOL SLIGHTLY IN CONCERT WITH INCREASING LOW-LEVEL
MOISTURE. WE HAVE 30-40 POPS BOTH DAYS...WITH SLIGHT CHANCES DURING
THE OVERNIGHT HOURS. HIGH TEMPS WILL BE SOLIDLY IN THE 80S WITH LOWS
IN THE 60S.

&&

.LONG TERM /MONDAY NIGHT THROUGH THURSDAY/...
THE UPPER SHORTWAVE NORTH OF THE AREA ON MONDAY WILL ESSENTIALLY
DISSOLVE ACROSS THE EASTERN CAROLINAS ON TUESDAY LEAVING A VERY WEAK
RIDGE PATTERN IN PLACE. ATLANTIC HIGH PRESSURE WILL PRODUCE AN
ONSHORE FLOW WITH SEA BREEZES DEVELOPING EACH AFTERNOON. SURFACE
DEWPOINTS WILL PERSIST IN THE MIDDLE 60S WITH HIGHS CLIMBING WELL
INTO THE 80S EACH DAY. ALTHOUGH THERE ARE NO STRONG FORCING
MECHANISMS...WE KEPT ISOLATED SHOWERS AND THUNDERSTORMS IN THE
FORECAST EACH AFTERNOON/EVENING. A COLD FRONT COULD MOVE INTO THE
AREA ON FRIDAY.

&&

.AVIATION /08Z FRIDAY THROUGH TUESDAY/...
VFR CONDITIONS WILL PREVAIL AT KCHS AND KSAV THROUGH 06Z SATURDAY.

EXTENDED AVIATION OUTLOOK...PRIMARILY VFR. ISOLATED TO SCATTERED
AFTERNOON SHOWERS/THUNDERSTORMS EXPECTED EACH AFTERNOON THROUGH
EARLY NEXT WEEK.

&&

.MARINE...
THROUGH TONIGHT...THE LOW LEVEL RIDGE AXIS REMAINS CONSTANT AND
SO DOES OUR FORECAST WITH A SOUTHERLY COMPONENT LESS THAN 15 KT
AND SEAS 3 FT OR LESS. DIRECTIONS SHOULD BACK A BIT MORE SE ALONG
THE GEORGIA COAST THIS AFTERNOON AS THE LAND WARMS AND THE SEA
BREEZE PUSHES INLAND.

ATLANTIC HIGH PRESSURE WILL BE THE PRIMARY MARINE INFLUENCE THROUGH
THE PERIOD WITH SOUTHERLY FLOW PREVAILING. WIND SPEEDS WILL PERSIST
IN THE 10-15 KT RANGE WITH SEAS 4 FT OR LESS.

&&

.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...NONE.

&&

$$

SYNOPSIS...
NEAR TERM...
SHORT TERM...JRL
LONG TERM...JRL
AVIATION...
MARINE...JRL

000
FXUS62 KCHS 170546
AFDCHS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
146 AM EDT FRI MAY 17 2013

.SYNOPSIS...
ATLANTIC HIGH PRESSURE WILL EXTEND INTO THE REGION THROUGH MUCH OF
THE WEEKEND...AS UPPER LEVEL ENERGY MOVES THROUGH. UPPER RIDGING
WILL THEN RETURN THROUGH MID WEEK...WITH A COLD FRONT POSSIBLY
APPROACHING LATE IN THE WEEK.

&&

.NEAR TERM /UNTIL 6 AM THIS MORNING/...
THIN JET CIRRUS EXPECTED FOR THE REMAINDER OF THE NIGHT. LOW
TEMPERATURES WILL BE RELATIVELY CLOSE TO NORMAL IN THE LOWER TO
MIDDLE 60S. FORECAST REMAINS ON TRACK SO ONLY MINOR TWEAKS MADE
WITH THE LATE EVENING UPDATE.

&&

.SHORT TERM /6 AM THIS MORNING THROUGH SUNDAY/...
FRIDAY AND FRIDAY NIGHT...THE PATTERN ALOFT WILL FEATURE A SHORTWAVE
TROUGH TO THE WEST CAUGHT WITHIN THE LARGER SCALE UPPER RIDGE. THIS
LOW AMPLITUDE SHORTWAVE WILL RESULT IN A BAGGY AREA IN THE UPPER
HEIGHTS THAT EXTENDS FROM THE UPPER MIDWEST TO THE DEEP SOUTH. THE
SURFACE WILL PRIMARILY BE DETERMINED BY SUBTROPICAL HIGH PRESSURE
OVER THE ATLANTIC THAT WILL CONTINUE TO EXTEND WESTWARD INTO THE
SOUTHEAST. THIS WILL RESULT IN A WARM SOUTHWEST FLOW IN THE LOW
LEVELS AND THICKNESS VALUES SUPPORT HIGHS IN THE UPPER 80S TO NEAR
90. THE MAIN FORECAST PROBLEM IS THE POTENTIAL FOR SHOWER AND
THUNDERSTORM DEVELOPMENT. THE CAP NOTED IN PREVIOUS DAYS WILL BE
NOTICEABLY WEAKER...DIMINISHING ALTOGETHER BY THE EARLY AFTERNOON.
THE MODELS ARE GENERATING 500-1000 J/KG OF CAPE AND SHOW A
PROGRESSIVE SEABREEZE IN THE AFTERNOON. THE MAIN LIMITING FACTOR
MAY BE THE DRY LOW LEVELS AND THE OVERALL MODEL RESPONSE SUPPORTS
ISOLATED CONVECTION AT BEST AND I HAVE KEPT THE SLIGHT CHANCE GOING.
OVERNIGHT...ANY LINGERING CONVECTION WILL QUICKLY DIMINISH AND A
MILD NIGHT IS ON TAP. LOWS WILL ONLY FALL INTO THE MID 60S IN MOST
AREAS.

SATURDAY THROUGH SUNDAY...FOR THE WEEKEND THE FORECAST AREA WILL SEE
PASSING SHORTWAVE ENERGY ALOFT WITHIN THE BAGGY TROUGH CAUGHT UNDER
THE LARGER SCALE RIDGE. THOUGH THE BULK OF THE ENERGY WILL REMAIN
NORTH OF THE REGION...IT WILL PROVIDE SOME SLIGHTLY LOWER HEIGHTS
EACH DAY. THE ENVIRONMENT WILL BECOME MODESTLY MORE CONDUCIVE TO
CONVECTION EACH DAY AS THE AMOUNT OF MOISTURE INCREASES AND THE MID
LEVELS COOL JUST A BIT. PWATS WILL INCREASE TO 1.3-1.4 ON SATURDAY
AND AROUND 1.5 BY SUNDAY. SATURDAY SOUNDINGS SHOW MODERATE
INSTABILITY DEVELOPING...WHICH MAY SUPPORT A FEW STRONG STORMS. BUT
WITH DCAPE VALUES ON THE LOW END DUE TO THE MOISTENING PROFILE...THE
THREAT OF SEVERE STORMS IS LOW. THE COVERAGE ON SUNDAY MAY BE A BIT
HIGHER WITH EVEN MORE MOISTURE TO WORK WITH...BUT POPS HAVE BEEN
KEPT IN THE CHANCE RANGE. TEMPS FEATURE A BIT OF A COOLING TREND
THANKS TO LOWERING THICKNESSES AND LINGERING CLOUD COVER...THOUGH
STILL SLIGHTLY ABOVE NORMAL EVEN BY SUNDAY.

&&

.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
A WEAK UPPER LEVEL PATTERN WILL ALLOW SHORTWAVE ENERGY TO PERSIST
OVER THE REGION THROUGH AT LEAST MONDAY...WITH A LESS DEFINED
SURFACE PATTERN INLAND OF THE ATLANTIC SURFACE HIGH. EXPECT
SHOWER/THUNDERSTORM ACTIVITY TO STILL BE DRIVEN BY DIURNAL
HEATING/INSTABILITY AND SEABREEZE FORCING...WITH JUST A SLIGHTLY
IMPROVED POTENTIAL FOR ISOLATED CONVECTION TO PERSIST AFTER SUNSET
UNDER SOME SYNOPTIC LEVEL SUPPORT. THE LOSS OF SHORTWAVE ENERGY
WITHIN A MORE WEAKLY RIDGED PATTERN ALOFT SHOULD RESULT IN JUST
ISOLATED THUNDERSTORM COVERAGE LIMITED TO THE DAYTIME HOURS
TUESDAY AND WEDNESDAY. WILL THUS REDUCE POPS TO THE 20 PERCENT
RANGE DURING THE MORE CLIMATOLOGICALLY FAVORED AFTERNOON/EARLY
EVENING PERIOD BY MID WEEK. A STRONGER SHORTWAVE TROUGH WILL SWING
SOUTHEAST LATE WEDNESDAY THROUGH THURSDAY...POSSIBLY PUSHING A
COLD FRONT TOWARD THE AREA BY LATE WEEK.

HIGH TEMPERATURES EACH DAY WILL GENERALLY RANGE FROM THE UPPER 80S
INLAND TO THE LOWER 80S ALONG THE COASTLINE. WILL NEED TO MONITOR
MODEL TRENDS FOR COOLER CONDITIONS BY THURSDAY IF THE FRONT CAN
SHIFT TOWARD THE FORECAST AREA.

&&

.AVIATION /06Z FRIDAY THROUGH TUESDAY/...
VFR CONDITIONS WILL PREVAIL AT KCHS AND KSAV THROUGH 06Z SATURDAY.

EXTENDED AVIATION OUTLOOK...PRIMARILY VFR. ISOLATED TO SCATTERED
AFTERNOON SHOWERS/THUNDERSTORMS EXPECTED EACH AFTERNOON THROUGH
EARLY NEXT WEEK.

&&

.MARINE...
QUIET MARINE CONDITIONS EXPECTED THROUGH THE OVERNIGHT PERIOD AS SURFACE
HIGH PRESSURE REMAINS SITUATED EAST OF THE WATERS. GENERALLY
EXPECT S/SW WINDS 10-15 KT WITH SEAS 2-3 FEET...HIGHEST BEYOND 20
NM.

FRIDAY THROUGH MONDAY...OVERALL THE PERIOD WILL BE MARKED BY HIGH
PRESSURE TO THE EAST EXTENDING WESTWARD ACROSS THE LOCAL WATERS.
WINDS WILL REMAIN SOUTH TO SOUTHWEST DURING THIS TIME WITH A FEW
MODEST SURGES OCCURRING AS THE GRADIENT TIGHTENS DUE TO WEAK INLAND
LOW PRESSURE. REGARDLESS...WINDS WILL REMAIN 15 KT OR LESS AND WAVE
HEIGHTS WILL BE 2 TO 4 FT...HIGHEST OVER THE OUTER WATERS.

&&

.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...NONE.

&&

$$

SYNOPSIS...
NEAR TERM...
SHORT TERM...BSH
LONG TERM...WMS
AVIATION...
MARINE...BSH/ECT

000
FXUS62 KCHS 170238
AFDCHS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
1038 PM EDT THU MAY 16 2013

.SYNOPSIS...
ATLANTIC HIGH PRESSURE WILL EXTEND INTO THE REGION THROUGH MUCH OF
THE WEEKEND...AS UPPER LEVEL ENERGY MOVES THROUGH. UPPER RIDGING
WILL THEN RETURN THROUGH MID WEEK...WITH A COLD FRONT POSSIBLY
APPROACHING LATE IN THE WEEK.

&&

.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
A SHORT WAVE DISTURBANCE WILL CONTINUE TO PUSH OFFSHORE THIS
EVENING...WITH WEAK RIDGING BUILDING ALOFT IN ITS WAKE FOR THE
OVERNIGHT HOURS. MEANWHILE AT THE SURFACE...ATLANTIC HIGH PRESSURE
WILL CONTINUE TO EXTEND INTO THE SOUTHEAST STATES. THE THICK HIGH
LEVEL CLOUD COVER ASSOCIATED WITH THE SHORT WAVE WILL CONTINUE TO
MOVE OUT OF THE AREA THIS EVENING...WITH ONLY SOME THIN JET CIRRUS
EXPECTED FOR THE REMAINDER OF THE NIGHT. LOW TEMPERATURES WILL BE
RELATIVELY CLOSE TO NORMAL IN THE LOWER TO MIDDLE 60S. FORECAST
REMAINS ON TRACK SO ONLY MINOR TWEAKS MADE WITH THE LATE EVENING
UPDATE.

&&

.SHORT TERM /6 AM FRIDAY MORNING THROUGH SUNDAY/...
FRIDAY AND FRIDAY NIGHT...THE PATTERN ALOFT WILL FEATURE A SHORTWAVE
TROUGH TO THE WEST CAUGHT WITHIN THE LARGER SCALE UPPER RIDGE. THIS
LOW AMPLITUDE SHORTWAVE WILL RESULT IN A BAGGY AREA IN THE UPPER
HEIGHTS THAT EXTENDS FROM THE UPPER MIDWEST TO THE DEEP SOUTH. THE
SURFACE WILL PRIMARILY BE DETERMINED BY SUBTROPICAL HIGH PRESSURE
OVER THE ATLANTIC THAT WILL CONTINUE TO EXTEND WESTWARD INTO THE
SOUTHEAST. THIS WILL RESULT IN A WARM SOUTHWEST FLOW IN THE LOW
LEVELS AND THICKNESS VALUES SUPPORT HIGHS IN THE UPPER 80S TO NEAR
90. THE MAIN FORECAST PROBLEM IS THE POTENTIAL FOR SHOWER AND
THUNDERSTORM DEVELOPMENT. THE CAP NOTED IN PREVIOUS DAYS WILL BE
NOTICEABLY WEAKER...DIMINISHING ALTOGETHER BY THE EARLY AFTERNOON.
THE MODELS ARE GENERATING 500-1000 J/KG OF CAPE AND SHOW A
PROGRESSIVE SEABREEZE IN THE AFTERNOON. THE MAIN LIMITING FACTOR
MAY BE THE DRY LOW LEVELS AND THE OVERALL MODEL RESPONSE SUPPORTS
ISOLATED CONVECTION AT BEST AND I HAVE KEPT THE SLIGHT CHANCE GOING.
OVERNIGHT...ANY LINGERING CONVECTION WILL QUICKLY DIMINISH AND A
MILD NIGHT IS ON TAP. LOWS WILL ONLY FALL INTO THE MID 60S IN MOST
AREAS.

SATURDAY THROUGH SUNDAY...FOR THE WEEKEND THE FORECAST AREA WILL SEE
PASSING SHORTWAVE ENERGY ALOFT WITHIN THE BAGGY TROUGH CAUGHT UNDER
THE LARGER SCALE RIDGE. THOUGH THE BULK OF THE ENERGY WILL REMAIN
NORTH OF THE REGION...IT WILL PROVIDE SOME SLIGHTLY LOWER HEIGHTS
EACH DAY. THE ENVIRONMENT WILL BECOME MODESTLY MORE CONDUCIVE TO
CONVECTION EACH DAY AS THE AMOUNT OF MOISTURE INCREASES AND THE MID
LEVELS COOL JUST A BIT. PWATS WILL INCREASE TO 1.3-1.4 ON SATURDAY
AND AROUND 1.5 BY SUNDAY. SATURDAY SOUNDINGS SHOW MODERATE
INSTABILITY DEVELOPING...WHICH MAY SUPPORT A FEW STRONG STORMS. BUT
WITH DCAPE VALUES ON THE LOW END DUE TO THE MOISTENING PROFILE...THE
THREAT OF SEVERE STORMS IS LOW. THE COVERAGE ON SUNDAY MAY BE A BIT
HIGHER WITH EVEN MORE MOISTURE TO WORK WITH...BUT POPS HAVE BEEN
KEPT IN THE CHANCE RANGE. TEMPS FEATURE A BIT OF A COOLING TREND
THANKS TO LOWERING THICKNESSES AND LINGERING CLOUD COVER...THOUGH
STILL SLIGHTLY ABOVE NORMAL EVEN BY SUNDAY.

&&

.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
A WEAK UPPER LEVEL PATTERN WILL ALLOW SHORTWAVE ENERGY TO PERSIST
OVER THE REGION THROUGH AT LEAST MONDAY...WITH A LESS DEFINED
SURFACE PATTERN INLAND OF THE ATLANTIC SURFACE HIGH. EXPECT
SHOWER/THUNDERSTORM ACTIVITY TO STILL BE DRIVEN BY DIURNAL
HEATING/INSTABILITY AND SEABREEZE FORCING...WITH JUST A SLIGHTLY
IMPROVED POTENTIAL FOR ISOLATED CONVECTION TO PERSIST AFTER SUNSET
UNDER SOME SYNOPTIC LEVEL SUPPORT. THE LOSS OF SHORTWAVE ENERGY
WITHIN A MORE WEAKLY RIDGED PATTERN ALOFT SHOULD RESULT IN JUST
ISOLATED THUNDERSTORM COVERAGE LIMITED TO THE DAYTIME HOURS
TUESDAY AND WEDNESDAY. WILL THUS REDUCE POPS TO THE 20 PERCENT
RANGE DURING THE MORE CLIMATOLOGICALLY FAVORED AFTERNOON/EARLY
EVENING PERIOD BY MID WEEK. A STRONGER SHORTWAVE TROUGH WILL SWING
SOUTHEAST LATE WEDNESDAY THROUGH THURSDAY...POSSIBLY PUSHING A
COLD FRONT TOWARD THE AREA BY LATE WEEK.

HIGH TEMPERATURES EACH DAY WILL GENERALLY RANGE FROM THE UPPER 80S
INLAND TO THE LOWER 80S ALONG THE COASTLINE. WILL NEED TO MONITOR
MODEL TRENDS FOR COOLER CONDITIONS BY THURSDAY IF THE FRONT CAN
SHIFT TOWARD THE FORECAST AREA.

&&

.AVIATION /03Z FRIDAY THROUGH TUESDAY/...
VFR CONDITIONS WILL PREVAIL AT KCHS AND KSAV THROUGH 00Z SATURDAY.

EXTENDED AVIATION OUTLOOK...PRIMARILY VFR. ISOLATED TO SCATTERED
AFTERNOON SHOWERS/THUNDERSTORMS EXPECTED EACH AFTERNOON THROUGH
EARLY NEXT WEEK.

&&

.MARINE...
QUIET MARINE CONDITIONS EXPECTED THROUGH THE OVERNIGHT PERIOD AS SURFACE
HIGH PRESSURE REMAINS SITUATED EAST OF THE WATERS. GENERALLY
EXPECT S/SW WINDS 10-15 KTS WITH SEAS 2-3 FEET...HIGHEST BEYOND 20
NM.

FRIDAY THROUGH MONDAY...OVERALL THE PERIOD WILL BE MARKED BY HIGH
PRESSURE TO THE EAST EXTENDING WESTWARD ACROSS THE LOCAL WATERS.
WINDS WILL REMAIN SOUTH TO SOUTHWEST DURING THIS TIME WITH A FEW
MODEST SURGES OCCURRING AS THE GRADIENT TIGHTENS DUE TO WEAK INLAND
LOW PRESSURE. REGARDLESS...WINDS WILL REMAIN 15 KTS OR LESS AND WAVE
HEIGHTS WILL BE 2 TO 4 FT...HIGHEST OVER THE OUTER WATERS.

&&

.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...NONE.

&&

$$

SYNOPSIS...
NEAR TERM...ECT/JAQ/JRL
SHORT TERM...BSH
LONG TERM...WMS
AVIATION...JAQ
MARINE...BSH/ECT

000
FXUS62 KCHS 162340
AFDCHS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
740 PM EDT THU MAY 16 2013

.SYNOPSIS...
ATLANTIC HIGH PRESSURE WILL EXTEND INTO THE REGION THROUGH MUCH OF
THE WEEKEND...AS UPPER LEVEL ENERGY MOVES THROUGH. UPPER RIDGING
WILL THEN RETURN THROUGH MID WEEK...WITH A COLD FRONT POSSIBLY
APPROACHING LATE IN THE WEEK.

&&

.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
A SHORT WAVE DISTURBANCE WILL CONTINUE TO PUSH OFFSHORE THIS
EVENING...WITH WEAK RIDGING BUILDING ALOFT IN ITS WAKE FOR THE
OVERNIGHT HOURS. MEANWHILE AT THE SURFACE...ATLANTIC HIGH PRESSURE
WILL CONTINUE TO EXTEND INTO THE SOUTHEAST STATES. THE THICK HIGH
LEVEL CLOUD COVER ASSOCIATED WITH THE SHORT WAVE WILL CONTINUE TO
MOVE OUT OF THE AREA THIS EVENING...WITH ONLY SOME THIN JET CIRRUS
EXPECTED FOR THE REMAINDER OF THE NIGHT. LOW TEMPERATURES WILL BE
RELATIVELY CLOSE TO NORMAL IN THE LOWER TO MIDDLE 60S.

&&

.SHORT TERM /6 AM FRIDAY MORNING THROUGH SUNDAY/...
FRIDAY AND FRIDAY NIGHT...THE PATTERN ALOFT WILL FEATURE A SHORTWAVE
TROUGH TO THE WEST CAUGHT WITHIN THE LARGER SCALE UPPER RIDGE. THIS
LOW AMPLITUDE SHORTWAVE WILL RESULT IN A BAGGY AREA IN THE UPPER
HEIGHTS THAT EXTENDS FROM THE UPPER MIDWEST TO THE DEEP SOUTH. THE
SURFACE WILL PRIMARILY BE DETERMINED BY SUBTROPICAL HIGH PRESSURE
OVER THE ATLANTIC THAT WILL CONTINUE TO EXTEND WESTWARD INTO THE
SOUTHEAST. THIS WILL RESULT IN A WARM SOUTHWEST FLOW IN THE LOW
LEVELS AND THICKNESS VALUES SUPPORT HIGHS IN THE UPPER 80S TO NEAR
90. THE MAIN FORECAST PROBLEM IS THE POTENTIAL FOR SHOWER AND
THUNDERSTORM DEVELOPMENT. THE CAP NOTED IN PREVIOUS DAYS WILL BE
NOTICEABLY WEAKER...DIMINISHING ALTOGETHER BY THE EARLY AFTERNOON.
THE MODELS ARE GENERATING 500-1000 J/KG OF CAPE AND SHOW A
PROGRESSIVE SEABREEZE IN THE AFTERNOON. THE MAIN LIMITING FACTOR
MAY BE THE DRY LOW LEVELS AND THE OVERALL MODEL RESPONSE SUPPORTS
ISOLATED CONVECTION AT BEST AND I HAVE KEPT THE SLIGHT CHANCE GOING.
OVERNIGHT...ANY LINGERING CONVECTION WILL QUICKLY DIMINISH AND A
MILD NIGHT IS ON TAP. LOWS WILL ONLY FALL INTO THE MID 60S IN MOST
AREAS.

SATURDAY THROUGH SUNDAY...FOR THE WEEKEND THE FORECAST AREA WILL SEE
PASSING SHORTWAVE ENERGY ALOFT WITHIN THE BAGGY TROUGH CAUGHT UNDER
THE LARGER SCALE RIDGE. THOUGH THE BULK OF THE ENERGY WILL REMAIN
NORTH OF THE REGION...IT WILL PROVIDE SOME SLIGHTLY LOWER HEIGHTS
EACH DAY. THE ENVIRONMENT WILL BECOME MODESTLY MORE CONDUCIVE TO
CONVECTION EACH DAY AS THE AMOUNT OF MOISTURE INCREASES AND THE MID
LEVELS COOL JUST A BIT. PWATS WILL INCREASE TO 1.3-1.4 ON SATURDAY
AND AROUND 1.5 BY SUNDAY. SATURDAY SOUNDINGS SHOW MODERATE
INSTABILITY DEVELOPING...WHICH MAY SUPPORT A FEW STRONG STORMS. BUT
WITH DCAPE VALUES ON THE LOW END DUE TO THE MOISTENING PROFILE...THE
THREAT OF SEVERE STORMS IS LOW. THE COVERAGE ON SUNDAY MAY BE A BIT
HIGHER WITH EVEN MORE MOISTURE TO WORK WITH...BUT POPS HAVE BEEN
KEPT IN THE CHANCE RANGE. TEMPS FEATURE A BIT OF A COOLING TREND
THANKS TO LOWERING THICKNESSES AND LINGERING CLOUD COVER...THOUGH
STILL SLIGHTLY ABOVE NORMAL EVEN BY SUNDAY.

&&

.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
A WEAK UPPER LEVEL PATTERN WILL ALLOW SHORTWAVE ENERGY TO PERSIST
OVER THE REGION THROUGH AT LEAST MONDAY...WITH A LESS DEFINED
SURFACE PATTERN INLAND OF THE ATLANTIC SURFACE HIGH. EXPECT
SHOWER/THUNDERSTORM ACTIVITY TO STILL BE DRIVEN BY DIURNAL
HEATING/INSTABILITY AND SEABREEZE FORCING...WITH JUST A SLIGHTLY
IMPROVED POTENTIAL FOR ISOLATED CONVECTION TO PERSIST AFTER SUNSET
UNDER SOME SYNOPTIC LEVEL SUPPORT. THE LOSS OF SHORTWAVE ENERGY
WITHIN A MORE WEAKLY RIDGED PATTERN ALOFT SHOULD RESULT IN JUST
ISOLATED THUNDERSTORM COVERAGE LIMITED TO THE DAYTIME HOURS
TUESDAY AND WEDNESDAY. WILL THUS REDUCE POPS TO THE 20 PERCENT
RANGE DURING THE MORE CLIMATOLOGICALLY FAVORED AFTERNOON/EARLY
EVENING PERIOD BY MID WEEK. A STRONGER SHORTWAVE TROUGH WILL SWING
SOUTHEAST LATE WEDNESDAY THROUGH THURSDAY...POSSIBLY PUSHING A
COLD FRONT TOWARD THE AREA BY LATE WEEK.

HIGH TEMPERATURES EACH DAY WILL GENERALLY RANGE FROM THE UPPER 80S
INLAND TO THE LOWER 80S ALONG THE COASTLINE. WILL NEED TO MONITOR
MODEL TRENDS FOR COOLER CONDITIONS BY THURSDAY IF THE FRONT CAN
SHIFT TOWARD THE FORECAST AREA.

&&

.AVIATION /00Z FRIDAY THROUGH TUESDAY/...
VFR CONDITIONS WILL PREVAIL AT KCHS AND KSAV THROUGH 00Z SATURDAY.

EXTENDED AVIATION OUTLOOK...PRIMARILY VFR. ISOLATED TO SCATTERED
AFTERNOON SHOWERS/THUNDERSTORMS EXPECTED EACH AFTERNOON THROUGH
EARLY NEXT WEEK.

&&

.MARINE...
QUIET MARINE CONDITIONS EXPECTED THROUGH THE OVERNIGHT PERIOD AS SURFACE
HIGH PRESSURE REMAINS SITUATED EAST OF THE WATERS. GENERALLY
EXPECT S/SW WINDS 10-15 KTS WITH SEAS 2-3 FEET...HIGHEST BEYOND 20
NM.

FRIDAY THROUGH MONDAY...OVERALL THE PERIOD WILL BE MARKED BY HIGH
PRESSURE TO THE EAST EXTENDING WESTWARD ACROSS THE LOCAL WATERS.
WINDS WILL REMAIN SOUTH TO SOUTHWEST DURING THIS TIME WITH A FEW
MODEST SURGES OCCURRING AS THE GRADIENT TIGHTENS DUE TO WEAK INLAND
LOW PRESSURE. REGARDLESS...WINDS WILL REMAIN 15 KTS OR LESS AND WAVE
HEIGHTS WILL BE 2 TO 4 FT...HIGHEST OVER THE OUTER WATERS.

&&

.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...NONE.

&&

$$

SYNOPSIS...
NEAR TERM...JAQ
SHORT TERM...BSH
LONG TERM...WMS
AVIATION...JAQ
MARINE...ECT/BSH

000
FXUS62 KCHS 161956
AFDCHS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
356 PM EDT THU MAY 16 2013

.SYNOPSIS...
ATLANTIC HIGH PRESSURE WILL EXTEND INTO THE REGION THROUGH MUCH OF
THE WEEKEND...AS UPPER LEVEL ENERGY MOVES THROUGH. UPPER RIDGING
WILL THEN RETURN THROUGH MID WEEK...WITH A COLD FRONT POSSIBLY
APPROACHING LATE IN THE WEEK.

&&

.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
QUIET WEATHER CONDITIONS EXPECTED OVERNIGHT AS ATLANTIC HIGH
PRESSURE REMAINS IN CONTROL OF THE FORECAST AREA. ALOFT...A
SHORTWAVE TROUGH WILL BE PUSHING OFF THE SOUTHEAST COAST AND WEAK
RIDGING WILL TAKE PLACE. EXPECTING MOST OF THE RESIDUAL CLOUD
COVER FROM THE SHORTWAVE TO MOVE OUT OF THE AREA AS WELL...LEAVING
ONLY SOME THIN HIGH CLOUDS. LOW TEMPERATURES WILL BE RELATIVELY
CLOSE TO NORMAL IN THE LOWER TO MIDDLE 60S.

&&

.SHORT TERM /6 AM FRIDAY MORNING THROUGH SUNDAY/...
FRIDAY AND FRIDAY NIGHT...THE PATTERN ALOFT WILL FEATURE A SHORTWAVE
TROUGH TO THE WEST CAUGHT WITHIN THE LARGER SCALE UPPER RIDGE. THIS
LOW AMPLITUDE SHORTWAVE WILL RESULT IN A BAGGY AREA IN THE UPPER
HEIGHTS THAT EXTENDS FROM THE UPPER MIDWEST TO THE DEEP SOUTH. THE
SURFACE WILL PRIMARILY BE DETERMINED BY SUBTROPICAL HIGH PRESSURE
OVER THE ATLANTIC THAT WILL CONTINUE TO EXTEND WESTWARD INTO THE
SOUTHEAST. THIS WILL RESULT IN A WARM SOUTHWEST FLOW IN THE LOW
LEVELS AND THICKNESS VALUES SUPPORT HIGHS IN THE UPPER 80S TO NEAR
90. THE MAIN FORECAST PROBLEM IS THE POTENTIAL FOR SHOWER AND
THUNDERSTORM DEVELOPMENT. THE CAP NOTED IN PREVIOUS DAYS WILL BE
NOTICEABLY WEAKER...DIMINISHING ALTOGETHER BY THE EARLY AFTERNOON.
THE MODELS ARE GENERATING 500-1000 J/KG OF CAPE AND SHOW A
PROGRESSIVE SEABREEZE IN THE AFTERNOON. THE MAIN LIMITING FACTOR
MAY BE THE DRY LOW LEVELS AND THE OVERALL MODEL RESPONSE SUPPORTS
ISOLATED CONVECTION AT BEST AND I HAVE KEPT THE SLIGHT CHANCE GOING.
OVERNIGHT...ANY LINGERING CONVECTION WILL QUICKLY DIMINISH AND A
MILD NIGHT IS ON TAP. LOWS WILL ONLY FALL INTO THE MID 60S IN MOST
AREAS.

SATURDAY THROUGH SUNDAY...FOR THE WEEKEND THE FORECAST AREA WILL SEE
PASSING SHORTWAVE ENERGY ALOFT WITHIN THE BAGGY TROUGH CAUGHT UNDER
THE LARGER SCALE RIDGE. THOUGH THE BULK OF THE ENERGY WILL REMAIN
NORTH OF THE REGION...IT WILL PROVIDE SOME SLIGHTLY LOWER HEIGHTS
EACH DAY. THE ENVIRONMENT WILL BECOME MODESTLY MORE CONDUCIVE TO
CONVECTION EACH DAY AS THE AMOUNT OF MOISTURE INCREASES AND THE MID
LEVELS COOL JUST A BIT. PWATS WILL INCREASE TO 1.3-1.4 ON SATURDAY
AND AROUND 1.5 BY SUNDAY. SATURDAY SOUNDINGS SHOW MODERATE
INSTABILITY DEVELOPING...WHICH MAY SUPPORT A FEW STRONG STORMS. BUT
WITH DCAPE VALUES ON THE LOW END DUE TO THE MOISTENING PROFILE...THE
THREAT OF SEVERE STORMS IS LOW. THE COVERAGE ON SUNDAY MAY BE A BIT
HIGHER WITH EVEN MORE MOISTURE TO WORK WITH...BUT POPS HAVE BEEN
KEPT IN THE CHANCE RANGE. TEMPS FEATURE A BIT OF A COOLING TREND
THANKS TO LOWERING THICKNESSES AND LINGERING CLOUD COVER...THOUGH
STILL SLIGHTLY ABOVE NORMAL EVEN BY SUNDAY.

&&

.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
A WEAK UPPER LEVEL PATTERN WILL ALLOW SHORTWAVE ENERGY TO PERSIST
OVER THE REGION THROUGH AT LEAST MONDAY...WITH A LESS DEFINED
SURFACE PATTERN INLAND OF THE ATLANTIC SURFACE HIGH. EXPECT
SHOWER/THUNDERSTORM ACTIVITY TO STILL BE DRIVEN BY DIURNAL
HEATING/INSTABILITY AND SEABREEZE FORCING...WITH JUST A SLIGHTLY
IMPROVED POTENTIAL FOR ISOLATED CONVECTION TO PERSIST AFTER SUNSET
UNDER SOME SYNOPTIC LEVEL SUPPORT. THE LOSS OF SHORTWAVE ENERGY
WITHIN A MORE WEAKLY RIDGED PATTERN ALOFT SHOULD RESULT IN JUST
ISOLATED THUNDERSTORM COVERAGE LIMITED TO THE DAYTIME HOURS
TUESDAY AND WEDNESDAY. WILL THUS REDUCE POPS TO THE 20 PERCENT
RANGE DURING THE MORE CLIMATOLOGICALLY FAVORED AFTERNOON/EARLY
EVENING PERIOD BY MID WEEK. A STRONGER SHORTWAVE TROUGH WILL SWING
SOUTHEAST LATE WEDNESDAY THROUGH THURSDAY...POSSIBLY PUSHING A
COLD FRONT TOWARD THE AREA BY LATE WEEK.

HIGH TEMPERATURES EACH DAY WILL GENERALLY RANGE FROM THE UPPER 80S
INLAND TO THE LOWER 80S ALONG THE COASTLINE. WILL NEED TO MONITOR
MODEL TRENDS FOR COOLER CONDITIONS BY THURSDAY IF THE FRONT CAN
SHIFT TOWARD THE FORECAST AREA.

&&

.AVIATION /20Z THURSDAY THROUGH TUESDAY/...
VFR CONDITIONS WILL PREVAIL AT KCHS AND KSAV THROUGH 18Z FRIDAY.

EXTENDED AVIATION OUTLOOK...PRIMARILY VFR. ISOLATED TO SCATTERED
AFTERNOON SHOWERS/THUNDERSTORMS EXPECTED EACH AFTERNOON THROUGH
EARLY NEXT WEEK.

&&

.MARINE...
QUIET MARINE CONDITIONS EXPECTED THROUGH THE OVERNIGHT PERIOD AS SURFACE
HIGH PRESSURE REMAINS SITUATED EAST OF THE WATERS. GENERALLY
EXPECT S/SW WINDS 10-15 KTS WITH SEAS 2-3 FEET...HIGHEST BEYOND 20
NM.

FRIDAY THROUGH MONDAY...OVERALL THE PERIOD WILL BE MARKED BY HIGH
PRESSURE TO THE EAST EXTENDING WESTWARD ACROSS THE LOCAL WATERS.
WINDS WILL REMAIN SOUTH TO SOUTHWEST DURING THIS TIME WITH A FEW
MODEST SURGES OCCURRING AS THE GRADIENT TIGHTENS DUE TO WEAK INLAND
LOW PRESSURE. REGARDLESS...WINDS WILL REMAIN 15 KTS OR LESS AND WAVE
HEIGHTS WILL BE 2 TO 4 FT...HIGHEST OVER THE OUTER WATERS.

&&

.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...NONE.

&&

$$

SYNOPSIS...
NEAR TERM...ECT
SHORT TERM...BSH
LONG TERM...WMS
AVIATION...ECT
MARINE...BSH/ECT

000
FXUS62 KCHS 161718
AFDCHS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
118 PM EDT THU MAY 16 2013

.SYNOPSIS...
ATLANTIC HIGH PRESSURE WILL EXTEND ACROSS THE REGION THROUGH LATE
WEEK. RAIN CHANCES WILL INCREASE OVER THE WEEKEND AS UPPER LEVEL
ENERGY MOVES OVER THE AREA...WITH A COLD FRONT APPROACHING FROM
THE WEST BY LATE NEXT WEEK.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
ATLANTIC HIGH PRESSURE WILL REMAIN THE DOMINANT WEATHER FEATURE
ACROSS THE FORECAST AREA TODAY. ALOFT...A SHORTWAVE TROUGH AND
ASSOCIATED VORT ENERGY CROSSING THROUGH THE AREA HAS RESULTED IN A
BLANKET OF MID AND HIGH LEVEL CLOUDS. AS THIS SHORTWAVE PROGRESS
EAST...EXPECTING CLOUDS TO GENERALLY MOVE WITH IT. ALTHOUGH LOW
LEVEL THICKNESS VALUES SUPPORT MAX TEMPERATURES IN THE UPPER
80S...THICKER CLOUD COVER WILL KEEP TEMPERATURES FROM REACHING
THEIR FULL POTENTIAL. MADE ADJUSTMENTS TO SKY COVER AND
TEMPERATURES TO ACCOUNT FOR LATEST TRENDS.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY/...
DRY WEATHER EXPECTED TO PERSIST TONIGHT WITH MILD MIN TEMPS IN
THE 60S AND PERIODS OF MID/UPPER CLOUDINESS AT TIMES.

FRIDAY...THE UPPER LEVEL TROUGH THAT SUPPORTED SIGNIFICANT
WEATHER OVER TEXAS WEDNESDAY NIGHT WILL GRADUALLY WEAKEN AS IT
APPROACHES THE EAST COAST LATE IN THE WEEK. ONLY REMNANT SHORTWAVE
ENERGY WILL PASS OVER THE FORECAST AREA BY FRIDAY. ALTHOUGH THE
MID AND UPPER LEVEL PROFILE WILL SEE AN INCREASE IN MOISTURE...THE
LOW LEVELS WILL STILL REMAIN RELATIVELY DRY UNDER THE REACH OF
ATLANTIC SURFACE HIGH PRESSURE. THUS EXPECT ONLY AN ISOLATED
SHOWER OR THUNDERSTORM TO DEVELOP ALONG AND INLAND OF THE
SEABREEZE DURING THE AFTERNOON HOURS...WITH ANY ACTIVITY
DIMINISHING AFTER SUNSET AS HEATING AND INSTABILITY WANE. MOST
AREAS WILL REMAIN DRY...WITH JUST AN INCREASE IN SKY COVER AS THE
DAY PROGRESSES. TEMPERATURES WILL RISE WELL ABOVE SEASONAL
NORMALS...PEAKING IN THE UPPER 80S AWAY FROM THE LOCALLY COOLER
COASTLINE.

SATURDAY...WEAK TROUGHING WILL LINGER OVER THE EAST COAST...AS A
SERIES OF TRANSIENT SHORTWAVES SHIFT INTO THE SOUTHEAST STATES.
ATLANTIC HIGH PRESSURE WILL CONTINUE TO BE THE MAIN SURFACE
FEATURE...ALLOWING WARM SOUTHERLY FLOW TO SUPPORT ABOVE NORMAL
HIGHS IN THE UPPER 80S INLAND TO THE LOWER 80S ALONG THE IMMEDIATE
COAST. EXPECT BETTER COVERAGE OF SHOWERS/THUNDERSTORMS ALONG AND
WEST OF THE SEABREEZE SATURDAY AFTERNOON WITHIN IMPROVED MOISTURE
PROFILES...AND HAVE THUS INCREASED POPS INTO THE CHANCE CATEGORY
FOR MUCH OF THE FORECAST AREA. BOTH GFS AND ECMWF SOLUTIONS SHOW
THE STRONGEST IMPULSE IN THE SERIES AMPLIFYING AS IT DESCENDS INTO
THE SOUTHERN APPALACHIANS SATURDAY NIGHT. THIS EXTRA ENERGY COULD
ALLOW INLAND CONVECTION TO PERSIST AFTER SUNSET...WITH MODEL
SOLUTIONS INDICATING VARYING DEGREES OF COVERAGE. PREFER TO
MAINTAIN MENTION OF SLIGHT CHANCE POPS OVERNIGHT...HIGHLIGHTING
MAINLY THE INLAND AREAS WITH THE BEST POTENTIAL FOR AN ISOLATED
NOCTURNAL SHOWER/THUNDERSTORM.

SUNDAY...SHORTWAVE ENERGY AND WEAK TROUGHING WILL STILL BE
MEANDERING OVER THE MID ATLANTIC AND SOUTHEAST STATES...ASSISTING
IN THE DEVELOPMENT OF A WEAK SURFACE WAVE ACROSS THE UPSTATE
REGION AND AN INCREASE IN DEEP MOISTURE. EXPECT ISOLATED TO
SCATTERED CONVECTION TO ONCE AGAIN DEVELOP ACROSS THE FAVORED
LOCATIONS INLAND OF THE SEABREEZE DURING THE AFTERNOON/EARLY
EVENING HOURS. LATEST ECMWF SOLUTION HAS BACKED OFF A BIT IN
COVERAGE FROM PREVIOUS RUNS...CONFINING THE BEST CHANCES FOR RAIN
ACROSS NORTHERN AREAS CLOSEST TO THE SHORTWAVE ENERGY. AT THIS
POINT...PREFER TO KEEP POPS IN THE 30 PERCENT RANGE AWAY FROM THE
IMMEDIATE COASTLINE. TEMPERATURES COULD BE A DEGREE OR TWO COOLER
THAN PREVIOUS DAYS CONSIDERING THICK SKY COVER AND A DECREASE IN
HEIGHTS ALOFT. EXPECT DAYTIME HIGHS TO RANGE MORE IN THE MID
80S...WITH A FEW LOCATIONS NEAR THE ALTAMAHA RIVER TOUCHING THE
UPPER 80S.

&&

.LONG TERM /SUNDAY NIGHT THROUGH WEDNESDAY/...
A WEAK UPPER LEVEL PATTERN WILL ALLOW SHORTWAVE ENERGY TO PERSIST
OVER THE REGION THROUGH AT LEAST MONDAY...WITH A LESS DEFINED
SURFACE PATTERN INLAND OF THE ATLANTIC SURFACE HIGH. EXPECT
SHOWER/THUNDERSTORM ACTIVITY TO STILL BE DRIVEN BY DIURNAL
HEATING/INSTABILITY AND SEABREEZE FORCING...WITH JUST A SLIGHTLY
IMPROVED POTENTIAL FOR ISOLATED CONVECTION TO PERSIST AFTER SUNSET
UNDER SOME SYNOPTIC LEVEL SUPPORT. THE LOSS OF SHORTWAVE ENERGY
WITHIN A MORE WEAKLY RIDGED PATTERN ALOFT SHOULD RESULT IN JUST
ISOLATED THUNDERSTORM COVERAGE LIMITED TO THE DAYTIME HOURS
TUESDAY AND WEDNESDAY. WILL THUS REDUCE POPS TO THE 20 PERCENT
RANGE DURING THE MORE CLIMATOLOGICALLY FAVORED AFTERNOON/EARLY
EVENING PERIOD BY MID WEEK. A STRONGER SHORTWAVE TROUGH WILL SWING
SOUTHEAST LATE WEDNESDAY THROUGH THURSDAY...POSSIBLY PUSHING A
COLD FRONT TOWARD THE AREA BY LATE WEEK.

HIGH TEMPERATURES EACH DAY WILL GENERALLY RANGE FROM THE UPPER 80S
INLAND TO THE LOWER 80S ALONG THE COASTLINE. WILL NEED TO MONITOR
MODEL TRENDS FOR COOLER CONDITIONS BY THURSDAY IF THE FRONT CAN
SHIFT TOWARD THE FORECAST AREA.

&&

.AVIATION /17Z THURSDAY THROUGH MONDAY/...
VFR CONDITIONS WILL PREVAIL AT KCHS AND KSAV THROUGH 18Z FRIDAY.

EXTENDED AVIATION OUTLOOK...VFR. ISOLATED DIURNAL CONVECTION IS
POSSIBLE OVER THE WEEKEND INTO MON.

&&

.MARINE...
SURFACE HIGH PRESSURE WILL REMAIN SITUATED EAST OF THE WATERS
TODAY WITH A TROUGH INLAND. THERE IS STILL SOMEWHAT OF A TIGHTENED
PRESSURE GRADIENT MAINLY ACROSS THE SC WATERS...HOWEVER IT IS A BIT
MORE RELAXED THAN WEDNESDAY. GENERALLY EXPECT SSW/SW 10-15
KTS THROUGH FRIDAY MORNING. SEAS WILL BE 2-4 FEET...HIGHEST
BEYOND 20 NM.

FRIDAY THROUGH MONDAY...SURFACE HIGH PRESSURE WILL REMAIN CENTERED
EAST OF THE MARINE ZONES THROUGH THE PERIOD. THIS PATTERN WILL
SUPPORT SOUTHERLY WINDS INTO EARLY NEXT WEEK...WITH WIND SPEEDS
GENERALLY RANGING FROM 10 TO 15 KT. WAVE HEIGHTS WILL BE 2 TO 4
FT...HIGHEST OVER THE OUTER WATERS.

&&

.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...NONE.

&&

$$

SYNOPSIS...
NEAR TERM...ECT
SHORT TERM...WMS
LONG TERM...WMS
AVIATION...ECT
MARINE...ECT/WMS

000
FXUS62 KCHS 161431
AFDCHS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
1031 AM EDT THU MAY 16 2013

.SYNOPSIS...
ATLANTIC HIGH PRESSURE WILL EXTEND ACROSS THE REGION THROUGH LATE
WEEK. RAIN CHANCES WILL INCREASE OVER THE WEEKEND AS UPPER LEVEL
ENERGY MOVES OVER THE AREA...WITH A COLD FRONT APPROACHING FROM
THE WEST BY LATE NEXT WEEK.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
ATLANTIC HIGH PRESSURE WILL REMAIN THE DOMINANT WEATHER FEATURE
ACROSS THE FORECAST AREA TODAY. ALOFT...A SHORTWAVE TROUGH AND
ASSOCIATED VORT ENERGY IS FORECAST TO CROSS THROUGH THE AREA.
THIS WILL RESULT IN NO MORE THAN AN INCREASE IN MID AND HIGH LEVEL
CLOUDS...WHICH IS ALREADY EVIDENT ON VISIBLE SATELLITE THIS
MORNING. LOW LEVEL THICKNESS VALUES SUPPORT MAX TEMPERATURES IN
THE MIDDLE TO UPPER 80S THIS AFTERNOON. CLOUD COVER SHOULD NOT
HAVE A HUGE IMPACT ON TEMPERATURES...HOWEVER THICKER CLOUDS COULD
KEEP HIGHS DOWN A DEGREE OR TWO. HAD TO ADJUST SKY COVER TO
ACCOUNT FOR LATEST TRENDS...BUT OTHERWISE NO MAJOR CHANGES WERE
NEEDED WITH THIS UPDATE.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY/...
DRY WEATHER EXPECTED TO PERSIST TONIGHT WITH MILD MIN TEMPS IN
THE 60S AND PERIODS OF MID/UPPER CLOUDINESS AT TIMES.

FRIDAY...THE UPPER LEVEL TROUGH THAT SUPPORTED SIGNIFICANT
WEATHER OVER TEXAS WEDNESDAY NIGHT WILL GRADUALLY WEAKEN AS IT
APPROACHES THE EAST COAST LATE IN THE WEEK. ONLY REMNANT SHORTWAVE
ENERGY WILL PASS OVER THE FORECAST AREA BY FRIDAY. ALTHOUGH THE
MID AND UPPER LEVEL PROFILE WILL SEE AN INCREASE IN MOISTURE...THE
LOW LEVELS WILL STILL REMAIN RELATIVELY DRY UNDER THE REACH OF
ATLANTIC SURFACE HIGH PRESSURE. THUS EXPECT ONLY AN ISOLATED
SHOWER OR THUNDERSTORM TO DEVELOP ALONG AND INLAND OF THE
SEABREEZE DURING THE AFTERNOON HOURS...WITH ANY ACTIVITY
DIMINISHING AFTER SUNSET AS HEATING AND INSTABILITY WANE. MOST
AREAS WILL REMAIN DRY...WITH JUST AN INCREASE IN SKY COVER AS THE
DAY PROGRESSES. TEMPERATURES WILL RISE WELL ABOVE SEASONAL
NORMALS...PEAKING IN THE UPPER 80S AWAY FROM THE LOCALLY COOLER
COASTLINE.

SATURDAY...WEAK TROUGHING WILL LINGER OVER THE EAST COAST...AS A
SERIES OF TRANSIENT SHORTWAVES SHIFT INTO THE SOUTHEAST STATES.
ATLANTIC HIGH PRESSURE WILL CONTINUE TO BE THE MAIN SURFACE
FEATURE...ALLOWING WARM SOUTHERLY FLOW TO SUPPORT ABOVE NORMAL
HIGHS IN THE UPPER 80S INLAND TO THE LOWER 80S ALONG THE IMMEDIATE
COAST. EXPECT BETTER COVERAGE OF SHOWERS/THUNDERSTORMS ALONG AND
WEST OF THE SEABREEZE SATURDAY AFTERNOON WITHIN IMPROVED MOISTURE
PROFILES...AND HAVE THUS INCREASED POPS INTO THE CHANCE CATEGORY
FOR MUCH OF THE FORECAST AREA. BOTH GFS AND ECMWF SOLUTIONS SHOW
THE STRONGEST IMPULSE IN THE SERIES AMPLIFYING AS IT DESCENDS INTO
THE SOUTHERN APPALACHIANS SATURDAY NIGHT. THIS EXTRA ENERGY COULD
ALLOW INLAND CONVECTION TO PERSIST AFTER SUNSET...WITH MODEL
SOLUTIONS INDICATING VARYING DEGREES OF COVERAGE. PREFER TO
MAINTAIN MENTION OF SLIGHT CHANCE POPS OVERNIGHT...HIGHLIGHTING
MAINLY THE INLAND AREAS WITH THE BEST POTENTIAL FOR AN ISOLATED
NOCTURNAL SHOWER/THUNDERSTORM.

SUNDAY...SHORTWAVE ENERGY AND WEAK TROUGHING WILL STILL BE
MEANDERING OVER THE MID ATLANTIC AND SOUTHEAST STATES...ASSISTING
IN THE DEVELOPMENT OF A WEAK SURFACE WAVE ACROSS THE UPSTATE
REGION AND AN INCREASE IN DEEP MOISTURE. EXPECT ISOLATED TO
SCATTERED CONVECTION TO ONCE AGAIN DEVELOP ACROSS THE FAVORED
LOCATIONS INLAND OF THE SEABREEZE DURING THE AFTERNOON/EARLY
EVENING HOURS. LATEST ECMWF SOLUTION HAS BACKED OFF A BIT IN
COVERAGE FROM PREVIOUS RUNS...CONFINING THE BEST CHANCES FOR RAIN
ACROSS NORTHERN AREAS CLOSEST TO THE SHORTWAVE ENERGY. AT THIS
POINT...PREFER TO KEEP POPS IN THE 30 PERCENT RANGE AWAY FROM THE
IMMEDIATE COASTLINE. TEMPERATURES COULD BE A DEGREE OR TWO COOLER
THAN PREVIOUS DAYS CONSIDERING THICK SKY COVER AND A DECREASE IN
HEIGHTS ALOFT. EXPECT DAYTIME HIGHS TO RANGE MORE IN THE MID
80S...WITH A FEW LOCATIONS NEAR THE ALTAMAHA RIVER TOUCHING THE
UPPER 80S.

&&

.LONG TERM /SUNDAY NIGHT THROUGH WEDNESDAY/...
A WEAK UPPER LEVEL PATTERN WILL ALLOW SHORTWAVE ENERGY TO PERSIST
OVER THE REGION THROUGH AT LEAST MONDAY...WITH A LESS DEFINED
SURFACE PATTERN INLAND OF THE ATLANTIC SURFACE HIGH. EXPECT
SHOWER/THUNDERSTORM ACTIVITY TO STILL BE DRIVEN BY DIURNAL
HEATING/INSTABILITY AND SEABREEZE FORCING...WITH JUST A SLIGHTLY
IMPROVED POTENTIAL FOR ISOLATED CONVECTION TO PERSIST AFTER SUNSET
UNDER SOME SYNOPTIC LEVEL SUPPORT. THE LOSS OF SHORTWAVE ENERGY
WITHIN A MORE WEAKLY RIDGED PATTERN ALOFT SHOULD RESULT IN JUST
ISOLATED THUNDERSTORM COVERAGE LIMITED TO THE DAYTIME HOURS
TUESDAY AND WEDNESDAY. WILL THUS REDUCE POPS TO THE 20 PERCENT
RANGE DURING THE MORE CLIMATOLOGICALLY FAVORED AFTERNOON/EARLY
EVENING PERIOD BY MID WEEK. A STRONGER SHORTWAVE TROUGH WILL SWING
SOUTHEAST LATE WEDNESDAY THROUGH THURSDAY...POSSIBLY PUSHING A
COLD FRONT TOWARD THE AREA BY LATE WEEK.

HIGH TEMPERATURES EACH DAY WILL GENERALLY RANGE FROM THE UPPER 80S
INLAND TO THE LOWER 80S ALONG THE COASTLINE. WILL NEED TO MONITOR
MODEL TRENDS FOR COOLER CONDITIONS BY THURSDAY IF THE FRONT CAN
SHIFT TOWARD THE FORECAST AREA.

&&

.AVIATION /14Z THURSDAY THROUGH MONDAY/...
VFR CONDITIONS WILL PREVAIL AT KCHS AND KSAV THROUGH 12Z FRIDAY.
SURFACE WINDS BELOW 15 KT WITH OCCASIONAL GUSTS 15-20 KT POSSIBLE
AT TIMES TODAY AT KCHS.

EXTENDED AVIATION OUTLOOK...VFR. ISOLATED DIURNAL CONVECTION IS
POSSIBLE OVER THE WEEKEND INTO MON.

&&

.MARINE...
SURFACE HIGH PRESSURE WILL REMAIN SITUATED EAST OF THE WATERS
TODAY WITH A TROUGH INLAND. THERE IS STILL SOMEWHAT OF A TIGHTENED
PRESSURE GRADIENT MAINLY ACROSS THE SC WATERS...HOWEVER IT IS A BIT
MORE RELAXED THAN WEDNESDAY. GENERALLY EXPECT SSW/SW 10-15
KTS THROUGH FRIDAY MORNING. SEAS WILL BE 2-4 FEET...HIGHEST
BEYOND 20 NM.

FRIDAY THROUGH MONDAY...SURFACE HIGH PRESSURE WILL REMAIN CENTERED
EAST OF THE MARINE ZONES THROUGH THE PERIOD. THIS PATTERN WILL
SUPPORT SOUTHERLY WINDS INTO EARLY NEXT WEEK...WITH WIND SPEEDS
GENERALLY RANGING FROM 10 TO 15 KT. WAVE HEIGHTS WILL BE 2 TO 4
FT...HIGHEST OVER THE OUTER WATERS.

&&

.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...NONE.

&&

$$

SYNOPSIS...
NEAR TERM...ECT
SHORT TERM...WMS
LONG TERM...WMS
AVIATION...ECT
MARINE...ECT/WMS

000
FXUS62 KCHS 161129
AFDCHS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
729 AM EDT THU MAY 16 2013

.SYNOPSIS...
ATLANTIC HIGH PRESSURE WILL EXTEND ACROSS THE REGION THROUGH LATE
WEEK. RAIN CHANCES WILL INCREASE OVER THE WEEKEND AS UPPER LEVEL
ENERGY MOVES OVER THE AREA...WITH A COLD FRONT APPROACHING FROM
THE WEST BY LATE NEXT WEEK.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
TODAY...THE UPPER LEVEL RIDGE AXIS WILL SLIDE OFF THE COAST WHILE
MODELS INDICATE A WEAK 500 MB SHORT WAVE EJECTING THROUGH THE
REGION AFTER MIDDAY. REALLY NO CONCERN FOR DIURNAL CONVECTIVE
INITIATION THIS AFTERNOON AS FORECAST SOUNDINGS PAINT A 2C-4C CAP
ON PROXIMITY SOUNDINGS ACROSS THE AREA WITH WEAK INSTABILITY/MOISTURE
PROFILES. THERE SHOULD BE AN OVERALL INCREASE IN UPPER LEVEL
MOISTURE THAT COULD COME INTO PLAY AS A FACTOR FOR HIGH TEMPS THIS
AFTERNOON. LOW LEVEL THICKNESS VALUES ARE WARMER THAN YESTERDAY
AND IF HIGH CLOUDS GO EVEN LESSER/THINNER THAN MODEL
EXPECTATIONS...WE COULD SEE QUITE A FEW INLAND SPOTS TOUCH 90.
WITH THIS UNCERTAINTY WE PRETTY MUCH RETAINED OUR PREVIOUS MAX
TEMP SCHEME WITH A COUPLE OF NUDGES UPWARD ALONG THE I-95 CORRIDOR
OF SOUTH CAROLINA. SW SYNOPTIC FLOW WILL RULE ONCE AGAIN...A BIT
WEAKER THAN WED...BUT STILL A DECENT RESULTANT SEA BREEZE ALONG
UPPER COASTAL SOUTH CAROLINA.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY/...
DRY WEATHER EXPECTED TO PERSIST TONIGHT WITH MILD MIN TEMPS IN
THE 60S AND PERIODS OF MID/UPPER CLOUDINESS AT TIMES.

FRIDAY...THE UPPER LEVEL TROUGH THAT SUPPORTED SIGNIFICANT
WEATHER OVER TEXAS WEDNESDAY NIGHT WILL GRADUALLY WEAKEN AS IT
APPROACHES THE EAST COAST LATE IN THE WEEK. ONLY REMNANT SHORTWAVE
ENERGY WILL PASS OVER THE FORECAST AREA BY FRIDAY. ALTHOUGH THE
MID AND UPPER LEVEL PROFILE WILL SEE AN INCREASE IN MOISTURE...THE
LOW LEVELS WILL STILL REMAIN RELATIVELY DRY UNDER THE REACH OF
ATLANTIC SURFACE HIGH PRESSURE. THUS EXPECT ONLY AN ISOLATED
SHOWER OR THUNDERSTORM TO DEVELOP ALONG AND INLAND OF THE
SEABREEZE DURING THE AFTERNOON HOURS...WITH ANY ACTIVITY
DIMINISHING AFTER SUNSET AS HEATING AND INSTABILITY WANE. MOST
AREAS WILL REMAIN DRY...WITH JUST AN INCREASE IN SKY COVER AS THE
DAY PROGRESSES. TEMPERATURES WILL RISE WELL ABOVE SEASONAL
NORMALS...PEAKING IN THE UPPER 80S AWAY FROM THE LOCALLY COOLER
COASTLINE.

SATURDAY...WEAK TROUGHING WILL LINGER OVER THE EAST COAST...AS A
SERIES OF TRANSIENT SHORTWAVES SHIFT INTO THE SOUTHEAST STATES.
ATLANTIC HIGH PRESSURE WILL CONTINUE TO BE THE MAIN SURFACE
FEATURE...ALLOWING WARM SOUTHERLY FLOW TO SUPPORT ABOVE NORMAL
HIGHS IN THE UPPER 80S INLAND TO THE LOWER 80S ALONG THE IMMEDIATE
COAST. EXPECT BETTER COVERAGE OF SHOWERS/THUNDERSTORMS ALONG AND
WEST OF THE SEABREEZE SATURDAY AFTERNOON WITHIN IMPROVED MOISTURE
PROFILES...AND HAVE THUS INCREASED POPS INTO THE CHANCE CATEGORY
FOR MUCH OF THE FORECAST AREA. BOTH GFS AND ECMWF SOLUTIONS SHOW
THE STRONGEST IMPULSE IN THE SERIES AMPLIFYING AS IT DESCENDS INTO
THE SOUTHERN APPALACHIANS SATURDAY NIGHT. THIS EXTRA ENERGY COULD
ALLOW INLAND CONVECTION TO PERSIST AFTER SUNSET...WITH MODEL
SOLUTIONS INDICATING VARYING DEGREES OF COVERAGE. PREFER TO
MAINTAIN MENTION OF SLIGHT CHANCE POPS OVERNIGHT...HIGHLIGHTING
MAINLY THE INLAND AREAS WITH THE BEST POTENTIAL FOR AN ISOLATED
NOCTURNAL SHOWER/THUNDERSTORM.

SUNDAY...SHORTWAVE ENERGY AND WEAK TROUGHING WILL STILL BE
MEANDERING OVER THE MID ATLANTIC AND SOUTHEAST STATES...ASSISTING
IN THE DEVELOPMENT OF A WEAK SURFACE WAVE ACROSS THE UPSTATE
REGION AND AN INCREASE IN DEEP MOISTURE. EXPECT ISOLATED TO
SCATTERED CONVECTION TO ONCE AGAIN DEVELOP ACROSS THE FAVORED
LOCATIONS INLAND OF THE SEABREEZE DURING THE AFTERNOON/EARLY
EVENING HOURS. LATEST ECMWF SOLUTION HAS BACKED OFF A BIT IN
COVERAGE FROM PREVIOUS RUNS...CONFINING THE BEST CHANCES FOR RAIN
ACROSS NORTHERN AREAS CLOSEST TO THE SHORTWAVE ENERGY. AT THIS
POINT...PREFER TO KEEP POPS IN THE 30 PERCENT RANGE AWAY FROM THE
IMMEDIATE COASTLINE. TEMPERATURES COULD BE A DEGREE OR TWO COOLER
THAN PREVIOUS DAYS CONSIDERING THICK SKY COVER AND A DECREASE IN
HEIGHTS ALOFT. EXPECT DAYTIME HIGHS TO RANGE MORE IN THE MID
80S...WITH A FEW LOCATIONS NEAR THE ALTAMAHA RIVER TOUCHING THE
UPPER 80S.

&&

.LONG TERM /SUNDAY NIGHT THROUGH WEDNESDAY/...
A WEAK UPPER LEVEL PATTERN WILL ALLOW SHORTWAVE ENERGY TO PERSIST
OVER THE REGION THROUGH AT LEAST MONDAY...WITH A LESS DEFINED
SURFACE PATTERN INLAND OF THE ATLANTIC SURFACE HIGH. EXPECT
SHOWER/THUNDERSTORM ACTIVITY TO STILL BE DRIVEN BY DIURNAL
HEATING/INSTABILITY AND SEABREEZE FORCING...WITH JUST A SLIGHTLY
IMPROVED POTENTIAL FOR ISOLATED CONVECTION TO PERSIST AFTER SUNSET
UNDER SOME SYNOPTIC LEVEL SUPPORT. THE LOSS OF SHORTWAVE ENERGY
WITHIN A MORE WEAKLY RIDGED PATTERN ALOFT SHOULD RESULT IN JUST
ISOLATED THUNDERSTORM COVERAGE LIMITED TO THE DAYTIME HOURS
TUESDAY AND WEDNESDAY. WILL THUS REDUCE POPS TO THE 20 PERCENT
RANGE DURING THE MORE CLIMATOLOGICALLY FAVORED AFTERNOON/EARLY
EVENING PERIOD BY MID WEEK. A STRONGER SHORTWAVE TROUGH WILL SWING
SOUTHEAST LATE WEDNESDAY THROUGH THURSDAY...POSSIBLY PUSHING A
COLD FRONT TOWARD THE AREA BY LATE WEEK.

HIGH TEMPERATURES EACH DAY WILL GENERALLY RANGE FROM THE UPPER 80S
INLAND TO THE LOWER 80S ALONG THE COASTLINE. WILL NEED TO MONITOR
MODEL TRENDS FOR COOLER CONDITIONS BY THURSDAY IF THE FRONT CAN
SHIFT TOWARD THE FORECAST AREA.

&&

.AVIATION /12Z THURSDAY THROUGH MONDAY/...
VFR CONDITIONS WILL PREVAIL AT KCHS AND KSAV THROUGH 12Z FRIDAY.
SURFACE WINDS BELOW 15 KT WITH OCCASIONAL GUSTS 15-20 KT POSSIBLE
AT TIMES TODAY AT KCHS.

EXTENDED AVIATION OUTLOOK...VFR. ISOLATED DIURNAL CONVECTION IS
POSSIBLE OVER THE WEEKEND INTO MON.

&&

.MARINE...
OVERNIGHT...MODERATE SW FLOW HAS BEEN ONGOING AND SEAS AT 06Z/07Z
HAVE BEEN RUNNING ABOUT 1 FT ABOVE WAVEWATCH FROM GRAYS REEF UP
TO THE EDISTO BUOY. THE TIGHTEST LOW LEVEL PRES GRADIENT WILL
CONTINUE ACROSS SOUTH CAROLINA TODAY BUT ENHANCEMENTS DO NOT APPEAR
TO BE AS EMPHATIC AS ON WED WHEN THE GRADIENT PINCHED STRONGER.
ON AVERAGE THROUGH TONIGHT...SSW TO SW FLOW 15 KT OR LESS WITH
SEAS 2 TO 4 FT. SOMEWHAT STRONGER FLOW AT TIMES...IN THE 15 TO 20
KT RANGE WILL BE FOUND AT FAVORED DIURNAL TIMES ALONG THE USUAL
STRETCHES OF CHARLESTON COUNTY OUT TOWARD BUOY 6 AND BEYOND.

FRIDAY THROUGH MONDAY...SURFACE HIGH PRESSURE WILL REMAIN CENTERED
EAST OF THE MARINE ZONES THROUGH THE PERIOD. THIS PATTERN WILL
SUPPORT SOUTHERLY WINDS INTO EARLY NEXT WEEK...WITH WIND SPEEDS
GENERALLY RANGING FROM 10 TO 15 KT. WAVE HEIGHTS WILL BE 2 TO 4
FT...HIGHEST OVER THE OUTER WATERS.

&&

.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...NONE.

&&

$$

SYNOPSIS...
NEAR TERM...
SHORT TERM...WMS
LONG TERM...WMS
AVIATION...
MARINE...WMS

000
FXUS62 KCHS 160805
AFDCHS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
405 AM EDT THU MAY 16 2013

.SYNOPSIS...
ATLANTIC HIGH PRESSURE WILL EXTEND ACROSS THE REGION THROUGH LATE
WEEK. RAIN CHANCES WILL INCREASE OVER THE WEEKEND AS UPPER LEVEL
ENERGY MOVES OVER THE AREA...WITH A COLD FRONT APPROACHING FROM
THE WEST BY LATE NEXT WEEK.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
PRE-DAWN...PATCHES OF THIN HIGH CLOUDS OVERNIGHT...OTHERWISE SKIES
GENERALLY CLEAR. TEMPS HAVE REMAINED ELEVATED AS LIGHT BREEZES HAVE
BEEN CONTINUOUS TO THE N OF I-16 AND MOST NOTICEABLE ALONG COASTAL
SOUTH CAROLINA. COOLEST TEMPS HAVE BEEN OVER FAR S GEORGIA WHERE
WINDS DECOUPLED SOONER IN THE LAP OF THE LOW LEVEL RIDGE AXIS.

TODAY...THE UPPER LEVEL RIDGE AXIS WILL SLIDE OFF THE COAST WHILE
MODELS INDICATE A WEAK 500 MB SHORT WAVE EJECTING THROUGH THE
REGION AFTER MIDDAY. REALLY NO CONCERN FOR DIURNAL CONVECTIVE
INITIATION THIS AFTERNOON AS FORECAST SOUNDINGS PAINT A 2C-4C CAP
ON PROXIMITY SOUNDINGS ACROSS THE AREA WITH WEAK INSTABILITY/MOISTURE
PROFILES. THERE SHOULD BE AN OVERALL INCREASE IN UPPER LEVEL MOISTURE
THAT COULD COME INTO PLAY AS A FACTOR FOR HIGH TEMPS THIS AFTERNOON.
LOW LEVEL THICKNESS VALUES ARE WARMER THAN YESTERDAY AND IF HIGH
CLOUDS GO EVEN LESSER/THINNER THAN MODEL EXPECTATIONS...WE COULD SEE
QUITE A FEW INLAND SPOTS TOUCH 90. WITH THIS UNCERTAINTY WE PRETTY
MUCH RETAINED OUR PREVIOUS MAX TEMP SCHEME WITH A COUPLE OF NUDGES
UPWARD ALONG THE I-95 CORRIDOR OF SOUTH CAROLINA. SW SYNOPTIC FLOW
WILL RULE ONCE AGAIN...A BIT WEAKER THAN WED...BUT STILL A DECENT
RESULTANT SEA BREEZE ALONG UPPER COASTAL SOUTH CAROLINA.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY/...
DRY WEATHER EXPECTED TO PERSIST TONIGHT WITH MILD MIN TEMPS IN
THE 60S AND PERIODS OF MID/UPPER CLOUDINESS AT TIMES.

FRIDAY...THE UPPER LEVEL TROUGH THAT SUPPORTED SIGNIFICANT
WEATHER OVER TEXAS WEDNESDAY NIGHT WILL GRADUALLY WEAKEN AS IT
APPROACHES THE EAST COAST LATE IN THE WEEK. ONLY REMNANT SHORTWAVE
ENERGY WILL PASS OVER THE FORECAST AREA BY FRIDAY. ALTHOUGH THE
MID AND UPPER LEVEL PROFILE WILL SEE AN INCREASE IN MOISTURE...THE
LOW LEVELS WILL STILL REMAIN RELATIVELY DRY UNDER THE REACH OF
ATLANTIC SURFACE HIGH PRESSURE. THUS EXPECT ONLY AN ISOLATED
SHOWER OR THUNDERSTORM TO DEVELOP ALONG AND INLAND OF THE
SEABREEZE DURING THE AFTERNOON HOURS...WITH ANY ACTIVITY
DIMINISHING AFTER SUNSET AS HEATING AND INSTABILITY WANE. MOST
AREAS WILL REMAIN DRY...WITH JUST AN INCREASE IN SKY COVER AS THE
DAY PROGRESSES. TEMPERATURES WILL RISE WELL ABOVE SEASONAL
NORMALS...PEAKING IN THE UPPER 80S AWAY FROM THE LOCALLY COOLER
COASTLINE.

SATURDAY...WEAK TROUGHING WILL LINGER OVER THE EAST COAST...AS A
SERIES OF TRANSIENT SHORTWAVES SHIFT INTO THE SOUTHEAST STATES.
ATLANTIC HIGH PRESSURE WILL CONTINUE TO BE THE MAIN SURFACE
FEATURE...ALLOWING WARM SOUTHERLY FLOW TO SUPPORT ABOVE NORMAL
HIGHS IN THE UPPER 80S INLAND TO THE LOWER 80S ALONG THE IMMEDIATE
COAST. EXPECT BETTER COVERAGE OF SHOWERS/THUNDERSTORMS ALONG AND
WEST OF THE SEABREEZE SATURDAY AFTERNOON WITHIN IMPROVED MOISTURE
PROFILES...AND HAVE THUS INCREASED POPS INTO THE CHANCE CATEGORY
FOR MUCH OF THE FORECAST AREA. BOTH GFS AND ECMWF SOLUTIONS SHOW
THE STRONGEST IMPULSE IN THE SERIES AMPLIFYING AS IT DESCENDS INTO
THE SOUTHERN APPALACHIANS SATURDAY NIGHT. THIS EXTRA ENERGY COULD
ALLOW INLAND CONVECTION TO PERSIST AFTER SUNSET...WITH MODEL
SOLUTIONS INDICATING VARYING DEGREES OF COVERAGE. PREFER TO
MAINTAIN MENTION OF SLIGHT CHANCE POPS OVERNIGHT...HIGHLIGHTING
MAINLY THE INLAND AREAS WITH THE BEST POTENTIAL FOR AN ISOLATED
NOCTURNAL SHOWER/THUNDERSTORM.

SUNDAY...SHORTWAVE ENERGY AND WEAK TROUGHING WILL STILL BE
MEANDERING OVER THE MID ATLANTIC AND SOUTHEAST STATES...ASSISTING
IN THE DEVELOPMENT OF A WEAK SURFACE WAVE ACROSS THE UPSTATE
REGION AND AN INCREASE IN DEEP MOISTURE. EXPECT ISOLATED TO
SCATTERED CONVECTION TO ONCE AGAIN DEVELOP ACROSS THE FAVORED
LOCATIONS INLAND OF THE SEABREEZE DURING THE AFTERNOON/EARLY
EVENING HOURS. LATEST ECMWF SOLUTION HAS BACKED OFF A BIT IN
COVERAGE FROM PREVIOUS RUNS...CONFINING THE BEST CHANCES FOR RAIN
ACROSS NORTHERN AREAS CLOSEST TO THE SHORTWAVE ENERGY. AT THIS
POINT...PREFER TO KEEP POPS IN THE 30 PERCENT RANGE AWAY FROM THE
IMMEDIATE COASTLINE. TEMPERATURES COULD BE A DEGREE OR TWO COOLER
THAN PREVIOUS DAYS CONSIDERING THICK SKY COVER AND A DECREASE IN
HEIGHTS ALOFT. EXPECT DAYTIME HIGHS TO RANGE MORE IN THE MID
80S...WITH A FEW LOCATIONS NEAR THE ALTAMAHA RIVER TOUCHING THE
UPPER 80S.

&&

.LONG TERM /SUNDAY NIGHT THROUGH WEDNESDAY/...
A WEAK UPPER LEVEL PATTERN WILL ALLOW SHORTWAVE ENERGY TO PERSIST
OVER THE REGION THROUGH AT LEAST MONDAY...WITH A LESS DEFINED
SURFACE PATTERN INLAND OF THE ATLANTIC SURFACE HIGH. EXPECT
SHOWER/THUNDERSTORM ACTIVITY TO STILL BE DRIVEN BY DIURNAL
HEATING/INSTABILITY AND SEABREEZE FORCING...WITH JUST A SLIGHTLY
IMPROVED POTENTIAL FOR ISOLATED CONVECTION TO PERSIST AFTER SUNSET
UNDER SOME SYNOPTIC LEVEL SUPPORT. THE LOSS OF SHORTWAVE ENERGY
WITHIN A MORE WEAKLY RIDGED PATTERN ALOFT SHOULD RESULT IN JUST
ISOLATED THUNDERSTORM COVERAGE LIMITED TO THE DAYTIME HOURS
TUESDAY AND WEDNESDAY. WILL THUS REDUCE POPS TO THE 20 PERCENT
RANGE DURING THE MORE CLIMATOLOGICALLY FAVORED AFTERNOON/EARLY
EVENING PERIOD BY MID WEEK. A STRONGER SHORTWAVE TROUGH WILL SWING
SOUTHEAST LATE WEDNESDAY THROUGH THURSDAY...POSSIBLY PUSHING A
COLD FRONT TOWARD THE AREA BY LATE WEEK.

HIGH TEMPERATURES EACH DAY WILL GENERALLY RANGE FROM THE UPPER 80S
INLAND TO THE LOWER 80S ALONG THE COASTLINE. WILL NEED TO MONITOR
MODEL TRENDS FOR COOLER CONDITIONS BY THURSDAY IF THE FRONT CAN
SHIFT TOWARD THE FORECAST AREA.

&&

.AVIATION /07Z THURSDAY THROUGH MONDAY/...
VFR CONDITIONS WILL PREVAIL AT KCHS AND KSAV THROUGH 06Z FRIDAY.

EXTENDED AVIATION OUTLOOK...VFR. ISOLATED DIURNAL CONVECTION IS
POSSIBLE OVER THE WEEKEND INTO MON.

&&

.MARINE...
OVERNIGHT...MODERATE SW FLOW HAS BEEN ONGOING AND SEAS AT 06Z/07Z
HAVE BEEN RUNNING ABOUT 1 FT ABOVE WAVEWATCH FROM GRAYS REEF UP
TO THE EDISTO BUOY. THE TIGHTEST LOW LEVEL PRES GRADIENT WILL
CONTINUE ACROSS SOUTH CAROLINA TODAY BUT ENHANCEMENTS DO NOT APPEAR
TO BE AS EMPHATIC AS ON WED WHEN THE GRADIENT PINCHED STRONGER.
ON AVERAGE THROUGH TONIGHT...SSW TO SW FLOW 15 KT OR LESS WITH
SEAS 2 TO 4 FT. SOMEWHAT STRONGER FLOW AT TIMES...IN THE 15 TO 20
KT RANGE WILL BE FOUND AT FAVORED DIURNAL TIMES ALONG THE USUAL
STRETCHES OF CHARLESTON COUNTY OUT TOWARD BUOY 6 AND BEYOND.

FRIDAY THROUGH MONDAY...SURFACE HIGH PRESSURE WILL REMAIN CENTERED
EAST OF THE MARINE ZONES THROUGH THE PERIOD. THIS PATTERN WILL
SUPPORT SOUTHERLY WINDS INTO EARLY NEXT WEEK...WITH WIND SPEEDS
GENERALLY RANGING FROM 10 TO 15 KT. WAVE HEIGHTS WILL BE 2 TO 4
FT...HIGHEST OVER THE OUTER WATERS.

&&

.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...NONE.

&&

$$

SYNOPSIS...
NEAR TERM...
SHORT TERM...WMS
LONG TERM...WMS
AVIATION...
MARINE...WMS

000
FXUS62 KCHS 160530
AFDCHS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
130 AM EDT THU MAY 16 2013

.SYNOPSIS...
ATLANTIC HIGH PRESSURE WILL EXTEND ACROSS THE REGION THIS WEEK.
RAIN CHANCES WILL INCREASE OVER THE WEEKEND AS UPPER LEVEL ENERGY
MOVES OVER THE AREA...WITH A COLD FRONT APPROACHING FROM THE WEST
BY THE MIDDLE OF NEXT WEEK.

&&

.NEAR TERM /UNTIL 6 AM THIS MORNING/...
AN UPPER LEVEL RIDGE WILL PREVAIL OVER THE REGION OVERNIGHT.
MEANWHILE AT THE SURFACE...ATLANTIC HIGH PRESSURE WILL EXPAND
FARTHER ACROSS THE FLORIDA PENINSULA AND GEORGIA AS A WEAK TROUGH
LINGERS INLAND. THE GRADIENT BETWEEN THESE TWO SURFACE FEATURES
COULD PREVENT WINDS FROM FULLY DECOUPLING OVER PARTS OF SOUTHEAST
SOUTH CAROLINA TONIGHT...ESPECIALLY THE CHARLESTON TRI-COUNTY
AREA. CLEAR SKIES SHOULD GIVE WAY TO INCREASING HIGH CIRRUS FROM
THE WEST OVERNIGHT AS THE NOSE OF AN H25 JET PUSHES TOWARD THE
REGION. GIVEN THESE FACTORS...TEMPERATURES WILL BE SLOW TO FALL.
WE BUMPED READINGS UP PER LATEST TRENDS ON OUR RECENT UPDATE.

&&

.SHORT TERM /6 AM THIS MORNING THROUGH SATURDAY/...
THURSDAY...FAIRLY QUIET WEATHER DAY EXPECTED ON THURSDAY. SURFACE
HIGH PRESSURE WILL REMAIN OFF THE SOUTHEAST COAST...WITH A WEAK
TROUGH INLAND. ALOFT...A BROAD UPPER TROUGH WILL APPROACH FROM THE
WEST...WITH ASSOCIATED VORT ENERGY FORECAST TO CROSS THROUGH THE
AREA. THIS WILL MAINLY RESULT IN AN INCREASE IN MID AND HIGH LEVEL
CLOUDS AS MODELS REMAIN CONSISTENT IN KEEPING THE FORECAST AREA
PRECIP-FREE. DESPITE INCREASING CLOUD COVER...THICKNESS VALUES ONCE
AGAIN SUPPORT HIGH TEMPS A FEW DEGREES ABOVE NORMAL...IN THE MIDDLE
AND UPPER 80S. LOWS WILL BE IN THE LOWER AND MIDDLE 60S.

FRIDAY...THE INLAND SURFACE TROUGH WILL BECOME LESS DEFINED...AND
THE FORECAST AREA WILL BE MAINLY UNDER THE INFLUENCE OF HIGH
PRESSURE OFFSHORE. MODELS CONTINUE TO HINT AT POSSIBLE CONVECTION
FIRING OFF THE SEA BREEZE IN THE AFTERNOON...WITH BEST CHANCES AWAY
FROM THE COAST. NO MORE THAN LOW END SLIGHT CHANCES ARE WARRANTED AT
THIS TIME AS COVERAGE SHOULD REMAIN ISOLATED. POPS WILL DIMINISH
AFTER SUNSET WITH LOSS OF INSOLATION.

SATURDAY...A WEAK PRESSURE PATTERN WILL BE IN PLACE...BOTH ALOFT AND
AT THE SURFACE WITH SOME UPPER LEVEL ENERGY STILL APPARENT. MODELS
ARE BIT MORE AGGRESSIVE SHOWING DIURNALLY DRIVEN PRECIP DEVELOPING
ONCE AGAIN IN THE AFTERNOON....THUS HAVE MAINTAINED CHANCE POPS
INLAND AND SLIGHT CHANCE POPS ALONG THE COAST. CONVECTIVE PARAMETERS
CURRENTLY ARE NOT ALL THAT IMPRESSIVE WITH WEAK MID LEVEL LAPSE
RATES AND WEAK SHEAR...SO SEVERE POTENTIAL IS LOW.

&&

.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
WEAK UPPER LEVEL RIDGING WILL PREVAIL ACROSS THE SOUTHEAST STATES
INTO EARLY NEXT WEEK...DEFLECTING A PROGRESSIVE SHORTWAVE TO THE
NORTHWEST SUNDAY INTO MONDAY. ATLANTIC HIGH PRESSURE WILL CONTINUE
TO BE THE MAIN FEATURE AT THE SURFACE...AND WITH LITTLE CHANGE IN
THE PATTERN UNTIL AS LATE AS WEDNESDAY...EXPECT SHOWER/THUNDERSTORM
POTENTIAL TO MAINLY BE DRIVEN BY TYPICAL DIURNAL HEATING/INSTABILITY
AND SEABREEZE FORCING. WILL THUS CONTINUE TO ADVERTISE ISOLATED TO
SCATTERED THUNDERSTORM DEVELOPMENT SUNDAY THROUGH WEDNESDAY DURING
THE CLIMATOLOGICALLY FAVORED AFTERNOON AND EARLY EVENING HOURS.
HIGH TEMPERATURES EACH AFTERNOON WILL RISE INTO THE UPPER 80S
INLAND...TO THE LOW 80S RIGHT ALONG THE COAST BEHIND THE
SEABREEZE. THE NEXT MAJOR SYNOPTIC FEATURE WILL BE AN UPPER TROUGH
AND ASSOCIATED COLD FRONT APPROACHING FROM THE WEST BY LATE TUESDAY
INTO WEDNESDAY.

&&

.AVIATION /06Z THURSDAY THROUGH MONDAY/...
VFR CONDITIONS WILL PREVAIL AT KCHS AND KSAV THROUGH 06Z FRIDAY.

EXTENDED AVIATION OUTLOOK...VFR. ISOLATED DIURNAL CONVECTION IS
POSSIBLE OVER THE WEEKEND.

&&

.MARINE...
TONIGHT...AN ENHANCED SURFACE PRESSURE GRADIENT BETWEEN ATLANTIC
HIGH PRESSURE AND A TROUGH OF LOW PRESSURE INLAND...IN COMBINATION
WITH WEAK LOW LEVEL JETTING...WILL KEEP SOUTH-SOUTHWEST WINDS ELEVATED
IN THE 15-20 KT RANGE INTO THE EARLY OVERNIGHT HOURS. AS THE HIGH
EXPANDS TO THE SOUTH AND THE GRADIENT WEAKENS LATE TONIGHT...SOUTHWEST
WINDS WILL BEGIN TO DIMINISH. SEAS WILL GENERALLY RANGE FROM 2-4 FT.

THURSDAY THROUGH MONDAY...ON THURSDAY SURFACE HIGH PRESSURE WILL
REMAIN CENTERED OFFSHORE EAST OF THE WATERS WITH A TROUGH INLAND.
INITIALLY THERE WILL BE SOME RESULTANT SURGE BETWEEN THE TWO WITH
WIND SPEEDS 15-20 KT POSSIBLE...MAINLY OVER THE SC WATERS. THE
TROUGH WILL GRADUALLY BECOME LESS DEFINED THURSDAY NIGHT AND ALLOW
FOR QUIET MARINE CONDITIONS TO RETURN. OVERALL SUB-SCA CRITERIA WILL
PREVAIL THROUGH THE WEEKEND...WITH WINDS GENERALLY 10-15 KT AND SEAS
2-3 FEET...HIGHEST OVER THE OUTER WATERS.

&&

.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...NONE.

&&

$$

SYNOPSIS...
NEAR TERM...
SHORT TERM...ECT
LONG TERM...WMS
AVIATION...
MARINE...ECT/JAQ

000
FXUS62 KCHS 160228
AFDCHS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
1028 PM EDT WED MAY 15 2013

.SYNOPSIS...
ATLANTIC HIGH PRESSURE WILL EXTEND ACROSS THE REGION THIS WEEK.
RAIN CHANCES WILL INCREASE OVER THE WEEKEND AS UPPER LEVEL ENERGY
MOVES OVER THE AREA...WITH A COLD FRONT APPROACHING FROM THE WEST
BY THE MIDDLE OF NEXT WEEK.

&&

.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
AN UPPER LEVEL RIDGE WILL PREVAIL OVER THE REGION TONIGHT.
MEANWHILE AT THE SURFACE...ATLANTIC HIGH PRESSURE WILL EXPAND
FARTHER ACROSS THE FLORIDA PENINSULA AND GEORGIA AS A WEAK TROUGH
LINGERS INLAND. THE GRADIENT BETWEEN THESE TWO SURFACE FEATURES
COULD PREVENT WINDS FROM FULLY DECOUPLING OVER PARTS OF SOUTHEAST
SOUTH CAROLINA TONIGHT...ESPECIALLY THE CHARLESTON TRI-COUNTY
AREA. CLEAR SKIES SHOULD GIVE WAY TO INCREASING HIGH CIRRUS FROM
THE WEST OVERNIGHT AS THE NOSE OF AN H25 JET PUSHES TOWARD THE
REGION. GIVEN THESE FACTORS...TEMPERATURES WILL BE SLOW TO FALL
THIS EVENING...WITH GOOD RADIATIONAL COOLING BRIEFLY SETTING UP
OVERNIGHT BEFORE HIGH CLOUDS EXPAND LATE. OVERALL...EXPECT LOW
TEMPERATURES IN THE LOWER TO MID 60S ACROSS MUCH OF THE AREA.

&&

.SHORT TERM /6 AM THURSDAY MORNING THROUGH SATURDAY/...
THURSDAY...FAIRLY QUIET WEATHER DAY EXPECTED ON THURSDAY. SURFACE
HIGH PRESSURE WILL REMAIN OFF THE SOUTHEAST COAST...WITH A WEAK
TROUGH INLAND. ALOFT...A BROAD UPPER TROUGH WILL APPROACH FROM THE
WEST...WITH ASSOCIATED VORT ENERGY FORECAST TO CROSS THROUGH THE
AREA. THIS WILL MAINLY RESULT IN AN INCREASE IN MID AND HIGH LEVEL
CLOUDS AS MODELS REMAIN CONSISTENT IN KEEPING THE FORECAST AREA
PRECIP-FREE. DESPITE INCREASING CLOUD COVER...THICKNESS VALUES ONCE
AGAIN SUPPORT HIGH TEMPS A FEW DEGREES ABOVE NORMAL...IN THE MIDDLE
AND UPPER 80S. LOWS WILL BE IN THE LOWER AND MIDDLE 60S.

FRIDAY...THE INLAND SURFACE TROUGH WILL BECOME LESS DEFINED...AND
THE FORECAST AREA WILL BE MAINLY UNDER THE INFLUENCE OF HIGH
PRESSURE OFFSHORE. MODELS CONTINUE TO HINT AT POSSIBLE CONVECTION
FIRING OFF THE SEA BREEZE IN THE AFTERNOON...WITH BEST CHANCES AWAY
FROM THE COAST. NO MORE THAN LOW END SLIGHT CHANCES ARE WARRANTED AT
THIS TIME AS COVERAGE SHOULD REMAIN ISOLATED. POPS WILL DIMINISH
AFTER SUNSET WITH LOSS OF INSOLATION.

SATURDAY...A WEAK PRESSURE PATTERN WILL BE IN PLACE...BOTH ALOFT AND
AT THE SURFACE WITH SOME UPPER LEVEL ENERGY STILL APPARENT. MODELS
ARE BIT MORE AGGRESSIVE SHOWING DIURNALLY DRIVEN PRECIP DEVELOPING
ONCE AGAIN IN THE AFTERNOON....THUS HAVE MAINTAINED CHANCE POPS
INLAND AND SLIGHT CHANCE POPS ALONG THE COAST. CONVECTIVE PARAMETERS
CURRENTLY ARE NOT ALL THAT IMPRESSIVE WITH WEAK MID LEVEL LAPSE
RATES AND WEAK SHEAR...SO SEVERE POTENTIAL IS LOW.

&&

.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
WEAK UPPER LEVEL RIDGING WILL PREVAIL ACROSS THE SOUTHEAST STATES
INTO EARLY NEXT WEEK...DEFLECTING A PROGRESSIVE SHORTWAVE TO THE
NORTHWEST SUNDAY INTO MONDAY. ATLANTIC HIGH PRESSURE WILL CONTINUE
TO BE THE MAIN FEATURE AT THE SURFACE...AND WITH LITTLE CHANGE IN
THE PATTERN UNTIL AS LATE AS WEDNESDAY...EXPECT SHOWER/THUNDERSTORM
POTENTIAL TO MAINLY BE DRIVEN BY TYPICAL DIURNAL HEATING/INSTABILITY
AND SEABREEZE FORCING. WILL THUS CONTINUE TO ADVERTISE ISOLATED TO
SCATTERED THUNDERSTORM DEVELOPMENT SUNDAY THROUGH WEDNESDAY DURING
THE CLIMATOLOGICALLY FAVORED AFTERNOON AND EARLY EVENING HOURS.
HIGH TEMPERATURES EACH AFTERNOON WILL RISE INTO THE UPPER 80S
INLAND...TO THE LOW 80S RIGHT ALONG THE COAST BEHIND THE
SEABREEZE. THE NEXT MAJOR SYNOPTIC FEATURE WILL BE AN UPPER TROUGH
AND ASSOCIATED COLD FRONT APPROACHING FROM THE WEST BY LATE TUESDAY
INTO WEDNESDAY.

&&

.AVIATION /03Z THURSDAY THROUGH MONDAY/...
VFR CONDITIONS WILL PREVAIL AT KCHS AND KSAV THROUGH 00Z FRIDAY.

EXTENDED AVIATION OUTLOOK...VFR. ISOLATED DIURNAL CONVECTION IS
POSSIBLE OVER THE WEEKEND.

&&

.MARINE...
TONIGHT...AN ENHANCED SURFACE PRESSURE GRADIENT BETWEEN ATLANTIC
HIGH PRESSURE AND A TROUGH OF LOW PRESSURE INLAND...IN COMBINATION
WITH WEAK LOW LEVEL JETTING...WILL KEEP SOUTH-SOUTHWEST WINDS ELEVATED
IN THE 15-20 KT RANGE INTO THE EARLY OVERNIGHT HOURS. AS THE HIGH
EXPANDS TO THE SOUTH AND THE GRADIENT WEAKENS LATE TONIGHT...SOUTHWEST
WINDS WILL BEGIN TO DIMINISH. SEAS WILL GENERALLY RANGE FROM 2-4 FT.

THURSDAY THROUGH MONDAY...ON THURSDAY SURFACE HIGH PRESSURE WILL
REMAIN CENTERED OFFSHORE EAST OF THE WATERS WITH A TROUGH INLAND.
INITIALLY THERE WILL BE SOME RESULTANT SURGE BETWEEN THE TWO WITH
WIND SPEEDS 15-20 KT POSSIBLE...MAINLY OVER THE SC WATERS. THE
TROUGH WILL GRADUALLY BECOME LESS DEFINED THURSDAY NIGHT AND ALLOW
FOR QUIET MARINE CONDITIONS TO RETURN. OVERALL SUB-SCA CRITERIA WILL
PREVAIL THROUGH THE WEEKEND...WITH WINDS GENERALLY 10-15 KT AND SEAS
2-3 FEET...HIGHEST OVER THE OUTER WATERS.

&&

.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...NONE.

&&

$$

SYNOPSIS...
NEAR TERM...JAQ
SHORT TERM...ECT
LONG TERM...WMS
AVIATION...JAQ
MARINE...JAQ/ECT

000
FXUS62 KCHS 152355
AFDCHS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
755 PM EDT WED MAY 15 2013

.SYNOPSIS...
ATLANTIC HIGH PRESSURE WILL EXTEND ACROSS THE REGION THIS WEEK.
RAIN CHANCES WILL INCREASE OVER THE WEEKEND AS UPPER LEVEL ENERGY
MOVES OVER THE AREA...WITH A COLD FRONT APPROACHING FROM THE WEST
BY THE MIDDLE OF NEXT WEEK.

&&

.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
AN UPPER LEVEL RIDGE WILL PREVAIL OVER THE REGION TONIGHT.
MEANWHILE AT THE SURFACE...ATLANTIC HIGH PRESSURE WILL EXPAND
FARTHER ACROSS THE FLORIDA PENINSULA AND GEORGIA AS A WEAK TROUGH
LINGERS INLAND. THE GRADIENT BETWEEN THESE TWO SURFACE FEATURES
COULD PREVENT WINDS FROM FULLY DECOUPLING OVER PARTS OF SOUTHEAST
SOUTH CAROLINA TONIGHT...ESPECIALLY THE CHARLESTON TRI-COUNTY
AREA. CLEAR SKIES SHOULD GIVE WAY TO INCREASING HIGH CIRRUS FROM
THE WEST OVERNIGHT AS THE NOSE OF AN H25 JET PUSHES TOWARD THE
REGION. GIVEN THESE FACTORS...TEMPERATURES WILL BE SLOW TO FALL
THIS EVENING...WITH GOOD RADIATIONAL COOLING BRIEFLY SETTING UP
OVERNIGHT BEFORE HIGH CLOUDS EXPAND LATE. OVERALL...EXPECT LOW
TEMPERATURES IN THE LOWER TO MID 60S ACROSS MUCH OF THE AREA.

&&

.SHORT TERM /6 AM THURSDAY MORNING THROUGH SATURDAY/...
THURSDAY...FAIRLY QUIET WEATHER DAY EXPECTED ON THURSDAY. SURFACE
HIGH PRESSURE WILL REMAIN OFF THE SOUTHEAST COAST...WITH A WEAK
TROUGH INLAND. ALOFT...A BROAD UPPER TROUGH WILL APPROACH FROM THE
WEST...WITH ASSOCIATED VORT ENERGY FORECAST TO CROSS THROUGH THE
AREA. THIS WILL MAINLY RESULT IN AN INCREASE IN MID AND HIGH LEVEL
CLOUDS AS MODELS REMAIN CONSISTENT IN KEEPING THE FORECAST AREA
PRECIP-FREE. DESPITE INCREASING CLOUD COVER...THICKNESS VALUES ONCE
AGAIN SUPPORT HIGH TEMPS A FEW DEGREES ABOVE NORMAL...IN THE MIDDLE
AND UPPER 80S. LOWS WILL BE IN THE LOWER AND MIDDLE 60S.

FRIDAY...THE INLAND SURFACE TROUGH WILL BECOME LESS DEFINED...AND
THE FORECAST AREA WILL BE MAINLY UNDER THE INFLUENCE OF HIGH
PRESSURE OFFSHORE. MODELS CONTINUE TO HINT AT POSSIBLE CONVECTION
FIRING OFF THE SEA BREEZE IN THE AFTERNOON...WITH BEST CHANCES AWAY
FROM THE COAST. NO MORE THAN LOW END SLIGHT CHANCES ARE WARRANTED AT
THIS TIME AS COVERAGE SHOULD REMAIN ISOLATED. POPS WILL DIMINISH
AFTER SUNSET WITH LOSS OF INSOLATION.

SATURDAY...A WEAK PRESSURE PATTERN WILL BE IN PLACE...BOTH ALOFT AND
AT THE SURFACE WITH SOME UPPER LEVEL ENERGY STILL APPARENT. MODELS
ARE BIT MORE AGGRESSIVE SHOWING DIURNALLY DRIVEN PRECIP DEVELOPING
ONCE AGAIN IN THE AFTERNOON....THUS HAVE MAINTAINED CHANCE POPS
INLAND AND SLIGHT CHANCE POPS ALONG THE COAST. CONVECTIVE PARAMETERS
CURRENTLY ARE NOT ALL THAT IMPRESSIVE WITH WEAK MID LEVEL LAPSE
RATES AND WEAK SHEAR...SO SEVERE POTENTIAL IS LOW.

&&

.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
WEAK UPPER LEVEL RIDGING WILL PREVAIL ACROSS THE SOUTHEAST STATES
INTO EARLY NEXT WEEK...DEFLECTING A PROGRESSIVE SHORTWAVE TO THE
NORTHWEST SUNDAY INTO MONDAY. ATLANTIC HIGH PRESSURE WILL CONTINUE
TO BE THE MAIN FEATURE AT THE SURFACE...AND WITH LITTLE CHANGE IN
THE PATTERN UNTIL AS LATE AS WEDNESDAY...EXPECT SHOWER/THUNDERSTORM
POTENTIAL TO MAINLY BE DRIVEN BY TYPICAL DIURNAL HEATING/INSTABILITY
AND SEABREEZE FORCING. WILL THUS CONTINUE TO ADVERTISE ISOLATED TO
SCATTERED THUNDERSTORM DEVELOPMENT SUNDAY THROUGH WEDNESDAY DURING
THE CLIMATOLOGICALLY FAVORED AFTERNOON AND EARLY EVENING HOURS.
HIGH TEMPERATURES EACH AFTERNOON WILL RISE INTO THE UPPER 80S
INLAND...TO THE LOW 80S RIGHT ALONG THE COAST BEHIND THE
SEABREEZE. THE NEXT MAJOR SYNOPTIC FEATURE WILL BE AN UPPER TROUGH
AND ASSOCIATED COLD FRONT APPROACHING FROM THE WEST BY LATE TUESDAY
INTO WEDNESDAY.

&&

.AVIATION /00Z THURSDAY THROUGH MONDAY/...
VFR CONDITIONS WILL PREVAIL AT KCHS AND KSAV THROUGH 00Z FRIDAY.

EXTENDED AVIATION OUTLOOK...VFR. ISOLATED DIURNAL CONVECTION IS
POSSIBLE OVER THE WEEKEND.

&&

.MARINE...
TONIGHT...AN ENHANCED SURFACE PRESSURE GRADIENT BETWEEN ATLANTIC
HIGH PRESSURE AND A TROUGH OF LOW PRESSURE INLAND...IN COMBINATION
WITH WEAK LOW LEVEL JETTING...WILL KEEP SOUTH-SOUTHWEST WINDS
ELEVATED IN THE 15-20 KT RANGE THROUGH MUCH OF THE EVENING. AS THE
HIGH EXPANDS TO THE SOUTH AND THE GRADIENT WEAKENS OVERNIGHT...SOUTHWEST
WINDS WILL BEGIN TO DIMINISH. SEAS WILL GENERALLY RANGE FROM 2-4
FT.

THURSDAY THROUGH MONDAY...ON THURSDAY SURFACE HIGH PRESSURE WILL
REMAIN CENTERED OFFSHORE EAST OF THE WATERS WITH A TROUGH INLAND.
INITIALLY THERE WILL BE SOME RESULTANT SURGE BETWEEN THE TWO WITH
WIND SPEEDS 15-20 KT POSSIBLE...MAINLY OVER THE SC WATERS. THE
TROUGH WILL GRADUALLY BECOME LESS DEFINED THURSDAY NIGHT AND ALLOW
FOR QUIET MARINE CONDITIONS TO RETURN. OVERALL SUB-SCA CRITERIA WILL
PREVAIL THROUGH THE WEEKEND...WITH WINDS GENERALLY 10-15 KT AND SEAS
2-3 FEET...HIGHEST OVER THE OUTER WATERS.

&&

.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...NONE.

&&

$$

SYNOPSIS...
NEAR TERM...JAQ
SHORT TERM...ECT
LONG TERM...WMS
AVIATION...JAQ
MARINE...JAQ/ECT

000
FXUS62 KCHS 152002
AFDCHS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
402 PM EDT WED MAY 15 2013

.SYNOPSIS...
ATLANTIC HIGH PRESSURE WILL EXTEND ACROSS THE REGION THIS WEEK.
RAIN CHANCES WILL INCREASE OVER THE WEEKEND AS UPPER LEVEL ENERGY
MOVES OVER THE AREA...WITH A COLD FRONT APPROACHING FROM THE WEST
BY THE MIDDLE OF NEXT WEEK.

&&

.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
QUIET WEATHER CONDITIONS WILL PERSIST THROUGH THE EVENING AND
OVERNIGHT PERIOD AS A TROUGH OF LOW PRESSURE PASSES THROUGH THE
NORTHEASTERN UNITED STATES AND INTO THE ATLANTIC WHILE SFC HIGH
PRESSURE GRADUALLY EXPANDS OVER THE FORECAST AREA FROM THE SOUTH.
WINDS WILL HAVE A TOUGH TIME DECOUPLING OVERNIGHT AS THIS PROCESS
OCCURS MAINLY DUE TO AN ENHANCED PRESSURE GRADIENT POSITIONED
BETWEEN THE TWO WEATHER FEATURES...ESPECIALLY OVER THE TRI COUNTY
AREA. HIGH CIRRUS SHOULD THEN DEVELOP TO OUR WEST AND SHIFT OVER THE
FORECAST AREA LATE TONIGHT AS MID/UPPER LVL MOISTURE INCREASE ALONG
THE NOSE OF AN H25 JET PUSHING INTO THE REGION. GIVEN THE INCREASING
HIGH CLOUD OVERNIGHT AND LACK OF STRONG RADIATIONAL COOLING...LOW
TEMPS WILL LIKELY BE WARMER THAN THE PREVIOUS NIGHT...IN THE LOW
TO MID 60S.

&&

.SHORT TERM /6 AM THURSDAY MORNING THROUGH SATURDAY/...
THURSDAY...FAIRLY QUIET WEATHER DAY EXPECTED ON THURSDAY. SURFACE
HIGH PRESSURE WILL REMAIN OFF THE SOUTHEAST COAST...WITH A WEAK
TROUGH INLAND. ALOFT...A BROAD UPPER TROUGH WILL APPROACH FROM THE
WEST...WITH ASSOCIATED VORT ENERGY FORECAST TO CROSS THROUGH THE
AREA. THIS WILL MAINLY RESULT IN AN INCREASE IN MID AND HIGH LEVEL
CLOUDS AS MODELS REMAIN CONSISTENT IN KEEPING THE FORECAST AREA
PRECIP-FREE. DESPITE INCREASING CLOUD COVER...THICKNESS VALUES ONCE
AGAIN SUPPORT HIGH TEMPS A FEW DEGREES ABOVE NORMAL...IN THE MIDDLE
AND UPPER 80S. LOWS WILL BE IN THE LOWER AND MIDDLE 60S.

FRIDAY...THE INLAND SURFACE TROUGH WILL BECOME LESS DEFINED...AND
THE FORECAST AREA WILL BE MAINLY UNDER THE INFLUENCE OF HIGH
PRESSURE OFFSHORE. MODELS CONTINUE TO HINT AT POSSIBLE CONVECTION
FIRING OFF THE SEA BREEZE IN THE AFTERNOON...WITH BEST CHANCES AWAY
FROM THE COAST. NO MORE THAN LOW END SLIGHT CHANCES ARE WARRANTED AT
THIS TIME AS COVERAGE SHOULD REMAIN ISOLATED. POPS WILL DIMINISH
AFTER SUNSET WITH LOSS OF INSOLATION.

SATURDAY...A WEAK PRESSURE PATTERN WILL BE IN PLACE...BOTH ALOFT AND
AT THE SURFACE WITH SOME UPPER LEVEL ENERGY STILL APPARENT. MODELS
ARE BIT MORE AGGRESSIVE SHOWING DIURNALLY DRIVEN PRECIP DEVELOPING
ONCE AGAIN IN THE AFTERNOON....THUS HAVE MAINTAINED CHANCE POPS
INLAND AND SLIGHT CHANCE POPS ALONG THE COAST. CONVECTIVE PARAMETERS
CURRENTLY ARE NOT ALL THAT IMPRESSIVE WITH WEAK MID LEVEL LAPSE
RATES AND WEAK SHEAR...SO SEVERE POTENTIAL IS LOW.

&&

.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
WEAK UPPER LEVEL RIDGING WILL PREVAIL ACROSS THE SOUTHEAST STATES
INTO EARLY NEXT WEEK...DEFLECTING A PROGRESSIVE SHORTWAVE TO THE
NORTHWEST SUNDAY INTO MONDAY. ATLANTIC HIGH PRESSURE WILL CONTINUE
TO BE THE MAIN FEATURE AT THE SURFACE...AND WITH LITTLE CHANGE IN
THE PATTERN UNTIL AS LATE AS WEDNESDAY...EXPECT SHOWER/THUNDERSTORM
POTENTIAL TO MAINLY BE DRIVEN BY TYPICAL DIURNAL HEATING/INSTABILITY
AND SEABREEZE FORCING. WILL THUS CONTINUE TO ADVERTISE ISOLATED TO
SCATTERED THUNDERSTORM DEVELOPMENT SUNDAY THROUGH WEDNESDAY DURING
THE CLIMATOLOGICALLY FAVORED AFTERNOON AND EARLY EVENING HOURS.
HIGH TEMPERATURES EACH AFTERNOON WILL RISE INTO THE UPPER 80S
INLAND...TO THE LOW 80S RIGHT ALONG THE COAST BEHIND THE
SEABREEZE. THE NEXT MAJOR SYNOPTIC FEATURE WILL BE AN UPPER TROUGH
AND ASSOCIATED COLD FRONT APPROACHING FROM THE WEST BY LATE TUESDAY
INTO WEDNESDAY.

&&

.AVIATION /20Z WEDNESDAY THROUGH MONDAY/...
VFR CONDITIONS WILL PREVAIL AT BOTH CHS AND SAV TERMINALS THROUGH
18Z THURSDAY. SOUTHWEST WINDS WILL GUST BETWEEN 15-20 KT AT TIMES
BETWEEN 18Z TO 23Z THIS AFTERNOON WITH AN INLAND MOVING
SEABREEZE...ESPECIALLY AT THE KCHS TERMINAL.

EXTENDED AVIATION OUTLOOK...VFR. ISOLATED DIURNAL CONVECTION IS
POSSIBLE OVER THE WEEKEND.

&&

.MARINE...
TONIGHT...WINDS WILL REMAIN NEAR 20 KTS OVER SC WATERS ALONG THE
CHARLESTON COUNTY COASTLINE AS WELL AS GRAYS REEF TO THE SAVANNAH
BUOY THIS EVENING WHILE AN ENHANCED GRADIENT REMAINS BETWEEN HIGH
PRESSURE OVER THE WATERS AND LOW PRESSURE PASSING TO THE NORTH.
CONDITIONS SHOULD GRADUALLY IMPROVE AFTER MIDNIGHT ONCE THE PRESSURE
GRADIENT SLACKENS AS LOW PRESSURE SHIFTS OVER THE WESTERN ATLANTIC
TO THE NORTH WHILE HIGH PRESSURE GRADUALLY BUILDS OVER THE WATERS
FROM THE SOUTH. SEAS WILL RANGE FROM 2-3 FT OVER MOST WATERS.
OCCASIONAL 4 FT SEAS WILL OCCUR OVER NORTHERN SC WATERS BEYOND
15 NM FROM THE COAST AND OUTER GA WATERS

THURSDAY THROUGH MONDAY...ON THURSDAY SURFACE HIGH PRESSURE WILL
REMAIN CENTERED OFFSHORE EAST OF THE WATERS WITH A TROUGH INLAND.
INITIALLY THERE WILL BE SOME RESULTANT SURGE BETWEEN THE TWO WITH
WIND SPEEDS 15-20 KTS POSSIBLE...MAINLY OVER THE SC WATERS. THE
TROUGH WILL GRADUALLY BECOME LESS DEFINED THURSDAY NIGHT AND ALLOW
FOR QUIET MARINE CONDITIONS TO RETURN. OVERALL SUB-SCA CRITERIA WILL
PREVAIL THROUGH THE WEEKEND...WITH WINDS GENERALLY 10-15 KT AND SEAS
2-3 FEET...HIGHEST OVER THE OUTER WATERS.

&&

.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...NONE.

&&

$$

SYNOPSIS...
NEAR TERM...DPB
SHORT TERM...ECT
LONG TERM...WMS
AVIATION...DPB/ECT
MARINE...DPB/ECT

000
FXUS62 KCHS 151748
AFDCHS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
148 PM EDT WED MAY 15 2013

.SYNOPSIS...
ATLANTIC HIGH PRESSURE WILL EXTEND ACROSS THE REGION THIS WEEK.
RAIN CHANCES WILL INCREASE OVER THE WEEKEND AS UPPER LEVEL ENERGY
MOVES OVER THE AREA...WITH A COLD FRONT APPROACHING FROM THE WEST
BY THE MIDDLE OF NEXT WEEK.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
QUIET WEATHER CONDITIONS WILL PERSIST OVER SOUTHEAST SOUTH CAROLINA
AND SOUTHEAST GEORGIA THIS AFTERNOON. TEMPS WILL CONTINUE TO WARM AS
MID LVL RIDGING PEAKS OVER THE SOUTHEASTERN UNITED STATES WHILE
WEST/SOUTHWEST SFC WINDS OCCUR ALONG THE NORTHERN EDGE OF SFC HIGH
PRESSURE CENTERED OVER NORTHERN FLORIDA. 1000-850MB THICKNESS
VALUES ALONG WITH SUNNY SKIES FAVOR OVERALL HIGH TEMPS IN THE
MID/UPPER 80S OVER ALL INLAND LOCATIONS. TEMPS WILL BE COOLER
ALONG THE COAST AS A SEABREEZE SHIFTS INLAND...AROUND 80 DEGREES.
WINDS WILL CONTINUE TO GUST BETWEEN 20-25 MPH THIS AFTERNOON AS
THE PRESSURE GRADIENT TIGHTENS BETWEEN LOW PRESSURE TO OUR NORTH
AND HIGH PRESSURE TO THE SOUTH. WIND GUSTS WILL BE HIGHEST OVER
NORTHERN SC ZONES WHERE THE PRESSURE GRADIENT AND SEABREEZE ARE
STRONGEST. WINDS WILL THEN BEGIN TO RELAX THIS EVENING WITH
DIURNAL HEAT LOSS.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY/...
A MILD NIGHT ON THE WAY AS ENOUGH GRADIENT FORECAST TO KEEP THE
LOWER LEVELS STIRRED N OF I-16...ALSO SURFACE DEW POINTS WILL BE
CLOSER TO 60 DEGREES MANY AREAS. LOWS 60-65 ACROSS THE AREA WITH
PERIODS OF HIGH CLOUDINESS AT TIMES.

THURSDAY...UPPER RIDGING WILL HAVE DAMPENED ACROSS THE EAST COAST
AHEAD OF A WEAK SHORTWAVE TROUGH APPROACHING FROM THE WEST. THE
LATEST RUNS OF THE ECMWF AND GFS MODELS SHOW VARYING DEGREES OF
SHORTWAVE ENERGY MOVING DOWNSTREAM OF THE BROAD TROUGH AXIS...YET
BOTH SOLUTIONS SHOW LITTLE TO NO PRECIPITATION POTENTIAL ON
THURSDAY. THE LACK OF SHOWER/THUNDERSTORM DEVELOPMENT IS LIKELY THE
RESULT OF RELATIVELY DRY AIR IN THE LOW LEVELS AND RESIDUAL
SUBSIDENCE WITH THE TROUGH AXIS STILL TO THE WEST. THUS WILL KEEP
RAIN CHANCES BELOW 15 PERCENT THROUGH THURSDAY NIGHT...WHILE
INDICATING AN INCREASE IN SKY COVER. HIGH TEMPERATURES WILL RISE
WELL ABOVE SEASONAL NORMALS...REACHING THE UPPER 80S AWAY FROM THE
LOCALLY COOLER COASTLINE.

FRIDAY...WEAK SHORTWAVE ENERGY WILL CONTINUE TO TRACK ACROSS THE
SOUTHEAST STATES AS THE UPPER TROUGH SHIFTS TOWARD THE COASTLINE.
CONSIDERING THE LOSS OF UPPER RIDGING...AS WELL AS EVIDENCE OF A
WEAK INLAND SURFACE TROUGH AND INCREASED DEEP LAYER
MOISTURE...LATEST THINKING IS THAT AN ISOLATED SHOWER/THUNDERSTORM
COULD DEVELOP ALONG AND INLAND OF THE SEABREEZE DURING THE
AFTERNOON/EARLY EVENING HOURS. WILL INDICATE SLIGHT CHANCE POPS
FROM 15Z TO 02Z ACCORDINGLY. MODEL GUIDANCE STILL SUGGESTS THAT
TEMPERATURES WILL RISE INTO THE UPPER 80S INLAND OF THE
SEABREEZE...AND WITH THICKNESS VALUES EVEN WARMER THAN
GUIDANCE...WILL CONTINUE WITH ABOVE NORMAL HIGH TEMPERATURES
FRIDAY AFTERNOON.

SATURDAY...THE UPPER LEVEL PATTERN WILL REMAIN RATHER WEAK INTO
THE WEEKEND...SUGGESTING LITTLE TO NO SUBSIDENCE AS SOME ENERGY
ALOFT COULD STILL SHIFT INTO THE REGION. THE SURFACE PATTERN WILL
BECOME A BIT MORE ILL DEFINED...WITH ATLANTIC HIGH PRESSURE
MAINTAINING SOME CONTROL OF THE COASTAL REGIONS AND A WEAKER
PRESSURE PATTERN FOUND FARTHER INLAND. NUMERICAL MODEL SOLUTIONS
ARE IN MUCH BETTER AGREEMENT IN INDICATING SEABREEZE INDUCED
DIURNAL SHOWERS/THUNDERSTORMS SATURDAY AFTERNOON UNDER IMPROVED
MOISTURE PROFILES ACROSS THE AREA. WILL THUS ADVERTISE SLIGHTLY
HIGHER RAIN POTENTIAL IN THE CHANCE CATEGORY AWAY FROM THE
IMMEDIATE COAST MAINLY DURING THE AFTERNOON HOURS...WITH ANY
ISOLATED TO SCATTERED THUNDERSTORMS LIKELY MOVING INLAND TOWARD
SUNSET. TEMPERATURES WILL PEAK IN THE UPPER 80S AWAY FROM THE
COASTLINE.

&&

.LONG TERM /SATURDAY NIGHT THROUGH TUESDAY/...
WEAK UPPER LEVEL RIDGING WILL PREVAIL ACROSS THE SOUTHEAST STATES
INTO EARLY NEXT WEEK...DEFLECTING A PROGRESSIVE SHORTWAVE TO THE
NORTHWEST SUNDAY INTO MONDAY. ATLANTIC HIGH PRESSURE WILL CONTINUE
TO BE THE MAIN FEATURE AT THE SURFACE...AND WITH LITTLE CHANGE IN
THE PATTERN UNTIL AS LATE AS WEDNESDAY...EXPECT SHOWER/THUNDERSTORM
POTENTIAL TO MAINLY BE DRIVEN BY TYPICAL DIURNAL HEATING/INSTABILITY
AND SEABREEZE FORCING. WILL THUS CONTINUE TO ADVERTISE ISOLATED TO
SCATTERED THUNDERSTORM DEVELOPMENT SUNDAY THROUGH WEDNESDAY DURING
THE CLIMATOLOGICALLY FAVORED AFTERNOON AND EARLY EVENING HOURS.
HIGH TEMPERATURES EACH AFTERNOON WILL RISE INTO THE UPPER 80S
INLAND...TO THE LOW 80S RIGHT ALONG THE COAST BEHIND THE
SEABREEZE. THE NEXT MAJOR SYNOPTIC FEATURE WILL BE AN UPPER TROUGH
AND ASSOCIATED COLD FRONT APPROACHING FROM THE WEST BY LATE TUESDAY
INTO WEDNESDAY.

&&

.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
VFR CONDITIONS WILL PREVAIL AT BOTH CHS AND SAV TERMINALS THROUGH
18Z THURSDAY. SOUTHWEST WINDS WILL GUST BETWEEN 15-20 KT AT TIMES
BETWEEN 18Z TO 23Z THIS AFTERNOON WITH AN INLAND MOVING
SEABREEZE...ESPECIALLY AT THE KCHS TERMINAL.

EXTENDED AVIATION OUTLOOK...VFR. ISOLATED DIURNAL CONVECTION IS
POSSIBLE OVER THE WEEKEND.

&&

.MARINE...
THE MARINE FORECAST REMAINS ON TRACK THIS AFTERNOON AS ATLANTIC HIGH
PRESSURE MAINTAINS A HOLD OVER THE WATERS. SOUTH WINDS WILL
GRADUALLY INCREASE THIS AFTERNOON AS THE PRESSURE GRADIENT TIGHTENS
BETWEEN A TROUGH OVER THE MIDLANDS AND ATLANTIC HIGH PRESSURE
SLIDING TO THE EAST. WINDS WILL REMAIN NEAR 15-20 KNOTS ALONG THE
CHARLESTON COUNTY COASTLINE CLOSEST TO AN INLAND MOVING SEABREEZE
CIRCULATION. WINDS MAY APPROACH SMALL CRAFT ADVISORY CONDITIONS IN
THE CHS HARBOR AND ALONG SOME CHARLESTON COUNTY BEACHES BUT THE
EVENT DURATION APPEARS TOO SMALL AND MARGINAL TO INCLUDE ANY
HEADLINES THROUGH THIS EVENING. SEAS WILL RANGE FROM 2-3 FT OVER
MOST WATERS. OCCASIONAL 4 FT SEAS MAY OCCUR OVER NORTHERN SC WATERS
BEYOND 15 NM FROM THE COAST.

TONIGHT...WINDS WILL REMAIN CLOSE TO 20 KT AT FOLLY BEACH AND FROM
GRAYS REEF TO THE SAVANNAH BUOY THIS EVENING AS CONDITIONS LOOK
FAVORABLE FOR WARM SEASON NOCTURNAL SURGES IN THE 00Z-06Z TIME
FRAME. SEAS WILL AVERAGE BETWEEN 2-4 FT.

THURSDAY THROUGH SUNDAY...ATLANTIC HIGH PRESSURE WILL CONTROL THE
PATTERN ACROSS THE MARINE ZONES THROUGH THE WEEKEND...ALLOWING
SOUTHERLY FLOW TO GENERALLY PREVAIL. WIND SPEEDS COULD PEAK IN THE
15 TO 20 KT RANGE ON THURSDAY...BEFORE AVERAGING 10 TO 15 KT
FRIDAY THROUGH SUNDAY. THERE COULD BE LOCAL SURGES WITH THE
SEABREEZE EACH AFTERNOON...HOWEVER SMALL CRAFT ADVISORIES ARE NOT
EXPECTED THROUGH THE PERIOD. WAVE HEIGHTS WILL RANGE FROM 2 TO 4
FT...HIGHEST IN THE OUTER WATERS.

&&

.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...NONE.

&&

$$

SYNOPSIS...
NEAR TERM...DPB
SHORT TERM...WMS
LONG TERM...WMS
AVIATION...DPB/WMS
MARINE...DPB/WMS

000
FXUS62 KCHS 151445
AFDCHS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
1045 AM EDT WED MAY 15 2013

.SYNOPSIS...
ATLANTIC HIGH PRESSURE WILL EXTEND ACROSS THE REGION THIS WEEK.
RAIN CHANCES WILL INCREASE OVER THE WEEKEND AS UPPER LEVEL ENERGY
MOVES OVER THE AREA...WITH A COLD FRONT APPROACHING FROM THE WEST
BY THE MIDDLE OF NEXT WEEK.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
ANOTHER QUIET DAY OF WEATHER IS EXPECTED OVER SOUTHEAST SOUTH
CAROLINA AND SOUTHEAST GEORGIA TODAY. TEMPS WILL WARM CONSIDERABLY
MORE THAN THE PREVIOUS DAY AS MID LVL RIDGING PEAKS OVER THE
SOUTHEASTERN UNITED STATES WHILE WEST/SOUTHWEST SFC WINDS DEVELOP
ALONG THE NORTHERN EDGE OF SFC HIGH PRESSURE CENTERED ALONG THE
FLORIDA/GEORGIA STATE LINE. 1000-850MB THICKNESS VALUES ALONG
WITH SUNNY SKIES SUGGEST OVERALL HIGH TEMPS IN THE MID/UPPER 80S
OVER INLAND AREAS AHEAD OF A DEVELOPING SEABREEZE ALONG THE COAST.
TEMPS WILL BE COOLER ALONG THE COAST...IN THE UPPER 70S TO AROUND 80
DEGREES. WE COULD SEE WIND GUSTS UP TO 20-25 MPH THIS AFTERNOON
AS THE PRESSURE GRADIENT BEGINS TO TIGHTEN BETWEEN LOW PRESSURE TO
OUR NORTH AND HIGH PRESSURE TO THE SOUTH. WINDS SHOULD THEN RELAX
THIS EVENING WITH DIURNAL HEAT LOSS.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY/...
A MILD NIGHT ON THE WAY AS ENOUGH GRADIENT FORECAST TO KEEP THE
LOWER LEVELS STIRRED N OF I-16...ALSO SURFACE DEW POINTS WILL BE
CLOSER TO 60 DEGREES MANY AREAS. LOWS 60-65 ACROSS THE AREA WITH
PERIODS OF HIGH CLOUDINESS AT TIMES.

THURSDAY...UPPER RIDGING WILL HAVE DAMPENED ACROSS THE EAST COAST
AHEAD OF A WEAK SHORTWAVE TROUGH APPROACHING FROM THE WEST. THE
LATEST RUNS OF THE ECMWF AND GFS MODELS SHOW VARYING DEGREES OF
SHORTWAVE ENERGY MOVING DOWNSTREAM OF THE BROAD TROUGH AXIS...YET
BOTH SOLUTIONS SHOW LITTLE TO NO PRECIPITATION POTENTIAL ON
THURSDAY. THE LACK OF SHOWER/THUNDERSTORM DEVELOPMENT IS LIKELY THE
RESULT OF RELATIVELY DRY AIR IN THE LOW LEVELS AND RESIDUAL
SUBSIDENCE WITH THE TROUGH AXIS STILL TO THE WEST. THUS WILL KEEP
RAIN CHANCES BELOW 15 PERCENT THROUGH THURSDAY NIGHT...WHILE
INDICATING AN INCREASE IN SKY COVER. HIGH TEMPERATURES WILL RISE
WELL ABOVE SEASONAL NORMALS...REACHING THE UPPER 80S AWAY FROM THE
LOCALLY COOLER COASTLINE.

FRIDAY...WEAK SHORTWAVE ENERGY WILL CONTINUE TO TRACK ACROSS THE
SOUTHEAST STATES AS THE UPPER TROUGH SHIFTS TOWARD THE COASTLINE.
CONSIDERING THE LOSS OF UPPER RIDGING...AS WELL AS EVIDENCE OF A
WEAK INLAND SURFACE TROUGH AND INCREASED DEEP LAYER
MOISTURE...LATEST THINKING IS THAT AN ISOLATED SHOWER/THUNDERSTORM
COULD DEVELOP ALONG AND INLAND OF THE SEABREEZE DURING THE
AFTERNOON/EARLY EVENING HOURS. WILL INDICATE SLIGHT CHANCE POPS
FROM 15Z TO 02Z ACCORDINGLY. MODEL GUIDANCE STILL SUGGESTS THAT
TEMPERATURES WILL RISE INTO THE UPPER 80S INLAND OF THE
SEABREEZE...AND WITH THICKNESS VALUES EVEN WARMER THAN
GUIDANCE...WILL CONTINUE WITH ABOVE NORMAL HIGH TEMPERATURES
FRIDAY AFTERNOON.

SATURDAY...THE UPPER LEVEL PATTERN WILL REMAIN RATHER WEAK INTO
THE WEEKEND...SUGGESTING LITTLE TO NO SUBSIDENCE AS SOME ENERGY
ALOFT COULD STILL SHIFT INTO THE REGION. THE SURFACE PATTERN WILL
BECOME A BIT MORE ILL DEFINED...WITH ATLANTIC HIGH PRESSURE
MAINTAINING SOME CONTROL OF THE COASTAL REGIONS AND A WEAKER
PRESSURE PATTERN FOUND FARTHER INLAND. NUMERICAL MODEL SOLUTIONS
ARE IN MUCH BETTER AGREEMENT IN INDICATING SEABREEZE INDUCED
DIURNAL SHOWERS/THUNDERSTORMS SATURDAY AFTERNOON UNDER IMPROVED
MOISTURE PROFILES ACROSS THE AREA. WILL THUS ADVERTISE SLIGHTLY
HIGHER RAIN POTENTIAL IN THE CHANCE CATEGORY AWAY FROM THE
IMMEDIATE COAST MAINLY DURING THE AFTERNOON HOURS...WITH ANY
ISOLATED TO SCATTERED THUNDERSTORMS LIKELY MOVING INLAND TOWARD
SUNSET. TEMPERATURES WILL PEAK IN THE UPPER 80S AWAY FROM THE
COASTLINE.

&&

.LONG TERM /SATURDAY NIGHT THROUGH TUESDAY/...
WEAK UPPER LEVEL RIDGING WILL PREVAIL ACROSS THE SOUTHEAST STATES
INTO EARLY NEXT WEEK...DEFLECTING A PROGRESSIVE SHORTWAVE TO THE
NORTHWEST SUNDAY INTO MONDAY. ATLANTIC HIGH PRESSURE WILL CONTINUE
TO BE THE MAIN FEATURE AT THE SURFACE...AND WITH LITTLE CHANGE IN
THE PATTERN UNTIL AS LATE AS WEDNESDAY...EXPECT SHOWER/THUNDERSTORM
POTENTIAL TO MAINLY BE DRIVEN BY TYPICAL DIURNAL HEATING/INSTABILITY
AND SEABREEZE FORCING. WILL THUS CONTINUE TO ADVERTISE ISOLATED TO
SCATTERED THUNDERSTORM DEVELOPMENT SUNDAY THROUGH WEDNESDAY DURING
THE CLIMATOLOGICALLY FAVORED AFTERNOON AND EARLY EVENING HOURS.
HIGH TEMPERATURES EACH AFTERNOON WILL RISE INTO THE UPPER 80S
INLAND...TO THE LOW 80S RIGHT ALONG THE COAST BEHIND THE
SEABREEZE. THE NEXT MAJOR SYNOPTIC FEATURE WILL BE AN UPPER TROUGH
AND ASSOCIATED COLD FRONT APPROACHING FROM THE WEST BY LATE TUESDAY
INTO WEDNESDAY.

&&

.AVIATION /15Z WEDNESDAY THROUGH SUNDAY/...
VFR THROUGH 12Z/16. SW WINDS WILL BECOME GUSTY AT TIMES FROM LATE
MORNING THROUGH THIS AFTERNOON...PARTICULARLY AT KCHS WITH A
SIGNIFICANT RESULTANT SEA BREEZE DEVELOPING AND A FAIRLY DEEP
MIXED LAYER.

EXTENDED AVIATION OUTLOOK...VFR. ISOLATED DIURNAL CONVECTION IS
POSSIBLE OVER THE WEEKEND.

&&

.MARINE...
TODAY...FAIRLY QUIET CONDITIONS WILL PERSIST OVER THE COASTAL WATERS
EARLY WITH ATLANTIC HIGH PRESSURE IN PLACE. SOUTH WINDS WILL THEN
GRADUALLY INCREASE DURING THE AFTERNOON AS THE PRESSURE GRADIENT
BEGINS TO TIGHTEN BETWEEN A TROUGH OVER THE MIDLANDS AND ATLANTIC
HIGH PRESSURE SLIDING TO THE EAST. WE COULD SEE SOUTH/SOUTHWEST
WINDS APPROACH 20 KNOTS ALONG THE CHARLESTON COUNTY COASTLINE WITH A
DEVELOPING SEABREEZE CIRCULATION. WINDS MAY APPROACH SMALL CRAFT
ADVISORY CONDITIONS IN THE CHS HARBOR AND LOCALLY ALONG SOME
CHARLESTON COUNTY BEACHES AS THE SEABREEZE CIRCULATION SHIFTS INLAND
BUT THE EVENT DURATION APPEARS TOO SMALL AND MARGINAL TO INCLUDE ANY
HEADLINES AT THIS TIME. SEAS WILL RANGE 1-2 FT NEARSHORE AND 2-3 FT
OFFSHORE.

TONIGHT...WINDS WILL REMAIN CLOSE TO 20 KT AT FOLLY BEACH AND FROM
GRAYS REEF TO THE SAVANNAH BUOY THIS EVENING AS CONDITIONS LOOK
FAVORABLE FOR WARM SEASON NOCTURNAL SURGES IN THE 00Z-06Z TIME
FRAME. SEAS WILL AVERAGE BETWEEN 2-4 FT.

THURSDAY THROUGH SUNDAY...ATLANTIC HIGH PRESSURE WILL CONTROL THE
PATTERN ACROSS THE MARINE ZONES THROUGH THE WEEKEND...ALLOWING
SOUTHERLY FLOW TO GENERALLY PREVAIL. WIND SPEEDS COULD PEAK IN THE
15 TO 20 KT RANGE ON THURSDAY...BEFORE AVERAGING 10 TO 15 KT
FRIDAY THROUGH SUNDAY. THERE COULD BE LOCAL SURGES WITH THE
SEABREEZE EACH AFTERNOON...HOWEVER SMALL CRAFT ADVISORIES ARE NOT
EXPECTED THROUGH THE PERIOD. WAVE HEIGHTS WILL RANGE FROM 2 TO 4
FT...HIGHEST IN THE OUTER WATERS.

&&

.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...NONE.

&&

$$

SYNOPSIS...
NEAR TERM...DPB
SHORT TERM...WMS
LONG TERM...WMS
AVIATION...DPB/WMS
MARINE...DPB/WMS

000
FXUS62 KCHS 151140
AFDCHS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
740 AM EDT WED MAY 15 2013

.SYNOPSIS...
ATLANTIC HIGH PRESSURE WILL EXTEND ACROSS THE REGION THIS WEEK.
RAIN CHANCES WILL INCREASE OVER THE WEEKEND AS UPPER LEVEL ENERGY
MOVES OVER THE AREA...WITH A COLD FRONT APPROACHING FROM THE WEST
BY THE MIDDLE OF NEXT WEEK.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
UPPER LEVEL RIDGING WILL BUILD OVER THE SOUTHEAST UNITED STATES
TODAY...WHILE SURFACE HIGH PRESSURE SHIFTS EAST OVER THE ATLANTIC.
THE ATMOSPHERE WILL BE CHARACTERIZED BY DEEP LAYERED DRYNESS AND
SOUNDINGS THAT INDICATE WARM MID LEVELS AND SINKING AIR. THE 925
MB RIDGE AXIS IS SETTLING TOWARD NE FLORIDA AND THIS MEANS A WEST
FLOW IN THE BOUNDARY LAYER WHICH SIGNALS WARMER WEATHER TODAY.
INCREASING LOW LEVEL THICKNESS VALUES AND THE WSW SURFACE WINDS
SHOULD KICK TEMPS INTO THE MID 80S WITH SOME INLAND UPPER 80S A
GOOD BET W OF I-95. CLEAR SKIES WILL GIVE WAY TO SOME LATE DAY
HIGH CLOUDS SPREADING IN FROM THE W BUT MOST OF THESE SHOULD BE
THIN. DIURNAL CUMULUS NOT ANTICIPATED TO BE MORE THAN FEW/SCT AT
BEST. SW WINDS WILL INCREASE TODAY ACROSS SE SOUTH CAROLINA AS THE
LOW LEVEL GRADIENT TIGHTENS. THE RESULTANT SEA BREEZE WILL SETUP
OVER THE CHARLESTON TRI-COUNTY AREA AND OCCASIONALLY BREEZY
CONDITIONS CAN BE EXPECTED THERE THIS AFTERNOON.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY/...
A MILD NIGHT ON THE WAY AS ENOUGH GRADIENT FORECAST TO KEEP THE
LOWER LEVELS STIRRED N OF I-16...ALSO SURFACE DEW POINTS WILL BE
CLOSER TO 60 DEGREES MANY AREAS. LOWS 60-65 ACROSS THE AREA WITH
PERIODS OF HIGH CLOUDINESS AT TIMES.

THURSDAY...UPPER RIDGING WILL HAVE DAMPENED ACROSS THE EAST COAST
AHEAD OF A WEAK SHORTWAVE TROUGH APPROACHING FROM THE WEST. THE
LATEST RUNS OF THE ECMWF AND GFS MODELS SHOW VARYING DEGREES OF
SHORTWAVE ENERGY MOVING DOWNSTREAM OF THE BROAD TROUGH AXIS...YET
BOTH SOLUTIONS SHOW LITTLE TO NO PRECIPITATION POTENTIAL ON
THURSDAY. THE LACK OF SHOWER/THUNDERSTORM DEVELOPMENT IS LIKELY THE
RESULT OF RELATIVELY DRY AIR IN THE LOW LEVELS AND RESIDUAL
SUBSIDENCE WITH THE TROUGH AXIS STILL TO THE WEST. THUS WILL KEEP
RAIN CHANCES BELOW 15 PERCENT THROUGH THURSDAY NIGHT...WHILE
INDICATING AN INCREASE IN SKY COVER. HIGH TEMPERATURES WILL RISE
WELL ABOVE SEASONAL NORMALS...REACHING THE UPPER 80S AWAY FROM THE
LOCALLY COOLER COASTLINE.

FRIDAY...WEAK SHORTWAVE ENERGY WILL CONTINUE TO TRACK ACROSS THE
SOUTHEAST STATES AS THE UPPER TROUGH SHIFTS TOWARD THE COASTLINE.
CONSIDERING THE LOSS OF UPPER RIDGING...AS WELL AS EVIDENCE OF A
WEAK INLAND SURFACE TROUGH AND INCREASED DEEP LAYER
MOISTURE...LATEST THINKING IS THAT AN ISOLATED SHOWER/THUNDERSTORM
COULD DEVELOP ALONG AND INLAND OF THE SEABREEZE DURING THE
AFTERNOON/EARLY EVENING HOURS. WILL INDICATE SLIGHT CHANCE POPS
FROM 15Z TO 02Z ACCORDINGLY. MODEL GUIDANCE STILL SUGGESTS THAT
TEMPERATURES WILL RISE INTO THE UPPER 80S INLAND OF THE
SEABREEZE...AND WITH THICKNESS VALUES EVEN WARMER THAN
GUIDANCE...WILL CONTINUE WITH ABOVE NORMAL HIGH TEMPERATURES
FRIDAY AFTERNOON.

SATURDAY...THE UPPER LEVEL PATTERN WILL REMAIN RATHER WEAK INTO
THE WEEKEND...SUGGESTING LITTLE TO NO SUBSIDENCE AS SOME ENERGY
ALOFT COULD STILL SHIFT INTO THE REGION. THE SURFACE PATTERN WILL
BECOME A BIT MORE ILL DEFINED...WITH ATLANTIC HIGH PRESSURE
MAINTAINING SOME CONTROL OF THE COASTAL REGIONS AND A WEAKER
PRESSURE PATTERN FOUND FARTHER INLAND. NUMERICAL MODEL SOLUTIONS
ARE IN MUCH BETTER AGREEMENT IN INDICATING SEABREEZE INDUCED
DIURNAL SHOWERS/THUNDERSTORMS SATURDAY AFTERNOON UNDER IMPROVED
MOISTURE PROFILES ACROSS THE AREA. WILL THUS ADVERTISE SLIGHTLY
HIGHER RAIN POTENTIAL IN THE CHANCE CATEGORY AWAY FROM THE
IMMEDIATE COAST MAINLY DURING THE AFTERNOON HOURS...WITH ANY
ISOLATED TO SCATTERED THUNDERSTORMS LIKELY MOVING INLAND TOWARD
SUNSET. TEMPERATURES WILL PEAK IN THE UPPER 80S AWAY FROM THE
COASTLINE.

&&

.LONG TERM /SATURDAY NIGHT THROUGH TUESDAY/...
WEAK UPPER LEVEL RIDGING WILL PREVAIL ACROSS THE SOUTHEAST STATES
INTO EARLY NEXT WEEK...DEFLECTING A PROGRESSIVE SHORTWAVE TO THE
NORTHWEST SUNDAY INTO MONDAY. ATLANTIC HIGH PRESSURE WILL CONTINUE
TO BE THE MAIN FEATURE AT THE SURFACE...AND WITH LITTLE CHANGE IN
THE PATTERN UNTIL AS LATE AS WEDNESDAY...EXPECT SHOWER/THUNDERSTORM
POTENTIAL TO MAINLY BE DRIVEN BY TYPICAL DIURNAL HEATING/INSTABILITY
AND SEABREEZE FORCING. WILL THUS CONTINUE TO ADVERTISE ISOLATED TO
SCATTERED THUNDERSTORM DEVELOPMENT SUNDAY THROUGH WEDNESDAY DURING
THE CLIMATOLOGICALLY FAVORED AFTERNOON AND EARLY EVENING HOURS.
HIGH TEMPERATURES EACH AFTERNOON WILL RISE INTO THE UPPER 80S
INLAND...TO THE LOW 80S RIGHT ALONG THE COAST BEHIND THE
SEABREEZE. THE NEXT MAJOR SYNOPTIC FEATURE WILL BE AN UPPER TROUGH
AND ASSOCIATED COLD FRONT APPROACHING FROM THE WEST BY LATE TUESDAY
INTO WEDNESDAY.

&&

.AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
VFR THROUGH 12Z/16. SW WINDS WILL BECOME GUSTY AT TIMES FROM LATE
MORNING THROUGH THIS AFTERNOON...PARTICULARLY AT KCHS WITH A
SIGNIFICANT RESULTANT SEA BREEZE DEVELOPING AND A FAIRLY DEEP
MIXED LAYER.

EXTENDED AVIATION OUTLOOK...VFR. ISOLATED DIURNAL CONVECTION IS
POSSIBLE OVER THE WEEKEND.

&&

.MARINE...
AN INLAND SURFACE TROUGH AND A TIGHT LOW LEVEL GRADIENT WILL ADD
FUEL TO A FEISTY RESULTANT SEA BREEZE ALONG COASTAL CHARLESTON
COUNTY THROUGH THE AFTERNOON HOURS. WINDS WILL REMAIN CLOSE TO
20 KT AT FOLLY BEACH THIS EVENING AS CONDITIONS LOOKING MORE
FAVORABLE FOR WARM SEASON NOCTURNAL SURGES IN THE 00Z-06Z TIME
FRAME. WINDS MAY BE CLOSE TO SMALL CRAFT ADVISORY CONDITIONS IN
THE HARBOR AND LOCALLY ALONG SOME CHARLESTON COUNTY BEACHES BUT WE
HAVE CAPPED IT OFF AT 15 TO 20 KT FOR NOW.

OVER GEORGIA WATERS...CONDITIONS WILL ALSO FAVOR DIURNAL EBBING
LATE MORNING AND EARLY AFTERNOON THEN MODEST SURGING THIS EVENING
POSSIBLY NEAR 20 KT AT TIMES FROM GRAYS REEF TO THE SAVANNAH BUOY.

THROUGH TONIGHT...SEAS WILL AVERAGE 2 TO 4 FT...HIGHEST OVER
OUTER GEORGIA WATERS AND OFF THE CHARLESTON COUNTY COAST LATER TODAY
AND TONIGHT.

THURSDAY THROUGH SUNDAY...ATLANTIC HIGH PRESSURE WILL CONTROL THE
PATTERN ACROSS THE MARINE ZONES THROUGH THE WEEKEND...ALLOWING
SOUTHERLY FLOW TO GENERALLY PREVAIL. WIND SPEEDS COULD PEAK IN THE
15 TO 20 KT RANGE ON THURSDAY...BEFORE AVERAGING 10 TO 15 KT
FRIDAY THROUGH SUNDAY. THERE COULD BE LOCAL SURGES WITH THE
SEABREEZE EACH AFTERNOON...HOWEVER SMALL CRAFT ADVISORIES ARE NOT
EXPECTED THROUGH THE PERIOD. WAVE HEIGHTS WILL RANGE FROM 2 TO 4
FT...HIGHEST IN THE OUTER WATERS.

&&

.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...NONE.

&&

$$

SYNOPSIS...
NEAR TERM...
SHORT TERM...WMS
LONG TERM...WMS
AVIATION...
MARINE...WMS