Area Forecast Discussion
Issued by NWS Charleston, SC

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
000
FXUS62 KCHS 062246
AFDCHS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
646 PM EDT MON JUL 6 2015

.SYNOPSIS...
ATLANTIC HIGH PRESSURE WILL PREVAIL WITH AN INLAND TROUGH OF LOW
PRESSURE LINGERING THROUGH THE WEEKEND.

&&

.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
MONDAY EVENING...ADJUSTED POSITION AND DURATION OF SLIGHT
CHANCE/CHANCE POPS TO ACCOUNT FOR ONGOING/EXPECTED TRENDS.
CONVECTION OVER SE GA WILL PUSH THROUGH THE SAVANNAH VICINITY AND
WILL ADVANCE NE TOWARD HXD AND NBC. OTHER SHOWERS/THUNDERSTORMS
WILL DEVELOP AND DISSIPATE MAINLY ALONG/WEST OF THE I-95 CORRIDOR
IN THE VICINITY THE SEA BREEZE AND CONVECTIVE OUTFLOW BOUNDARIES.
MLCAPES ONLY AROUND 1500 J/KG HAS TRANSLATED TO LIMITED UPDRAFT
STRENGTH WHILE DOWNDRAFT CAPES HAVE REMAINED WELL BELOW 1000 J/KG.
THUS...WHILE SOME AREAS WILL RECEIVE SOME LIGHTNING AND BRIEF
HEAVY RAIN...THE POTENTIAL FOR SEVERE WEATHER WILL REMAIN LOW.

AFTER DARK...SHOWERS/THUNDERSTORMS OVER LAND SHOULD DISSIPATE...
AND RAIN-FREE CONDITIONS ARE EXPECTED OVERNIGHT. SOME MARINE
BASED CONVECTION COULD REDEVELOP OVER THE COASTAL WATERS AS LOW-
LEVEL CONVERGENCE SHIFTS OFFSHORE ALONG THE WESTERN WALL OF THE
GULF STREAM...BUT LOW-LEVEL TRAJECTORIES FAVOR KEEPING ANY SUCH
ACTIVITY OFFSHORE. LOWS WILL RANGE FROM THE LOWER-MID 70S INLAND
WITH UPPER 70S ALONG THE BEACHES AND DOWNTOWN CHARLESTON.

&&

.SHORT TERM /6 AM TUESDAY MORNING THROUGH THURSDAY/...
TUESDAY...A REMNANT UPPER TROUGH AXIS WILL WEAKEN ACROSS THE SC
MIDLANDS AND A BROAD UPPER RIDGE WILL REBUILD. IN THE LOWER LEVELS A
STEADY SOUTHERLY FLOW WILL BE IN PLACE...BRINGING MOISTURE OFF THE
WESTERN ATLANTIC. WE MAY SEE SOME SHOWERS MOVING ONSHORE DURING THE
MORNING DUE TO WEAK CONVERGENCE OFF THE COAST AND THE LANDWARD STORM
MOTION. THE SEA BREEZE WILL DEVELOP AND PUSH INLAND FAIRLY EARLY IN
THE AFTERNOON GIVEN THE SYNOPTIC SCALE FLOW. ALTHOUGH MID-LEVELS
WILL BE WARMING AND THE CAP WILL STRENGTHEN...SURFACE DEWPOINTS IN
THE LOWER 70S AND TEMPS IN THE LOWER 90S WILL YIELD 1500-2000 J/KG
CAPES. SUCH A THERMODYNAMIC ENVIRONMENT COMBINED WITH FORCING ALONG
THE SEA BREEZE SHOULD BE SUFFICIENT TO PRODUCE ISOLATED TO SCATTERED
SHOWERS AND THUNDERSTORMS TUESDAY AFTERNOON AND EARLY EVENING.

WEDNESDAY AND THURSDAY...A FAIRLY SIMILAR PATTERN WILL PERSIST
WEDNESDAY AND THURSDAY THOUGH THE UPPER RIDGE WILL CONTINUE TO
STRENGTHEN. THIS WILL RESULT IN HIGH TEMPS PUSHING INTO THE MIDDLE
90S BY MID WEEK. MID- LEVEL CAPPING WILL ALSO STRENGTHEN BUT A
ROBUST AFTERNOON SEA BREEZE AND CONSIDERABLE SURFACE-BASED
INSTABILITY WILL STILL ALLOW FOR 20-30 PERCENT RAIN CHANCES MAINLY
DURING THE AFTERNOON/EVENING. ALTHOUGH WE ARE LACKING APPRECIABLE
SHEAR OR UPPER SYNOPTIC SCALE FORCING MECHANISMS...GIVEN THE
SURFACE-BASED BUOYANCY AND CONVECTIVE OUTFLOW BOUNDARIES...
ISOLATED SEVERE THUNDERSTORMS WILL BE POSSIBLE EACH DAY.

&&

.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
MEDIUM RANGE GUIDANCE IS IN GOOD AGREEMENT WITH THE OVERALL SYNOPTIC
PATTERN THROUGH THE LONG TERM PERIOD. UPPER LEVEL RIDGING WILL
CONTINUE TO RETROGRADE...SHIFTING OVER THE REGION...THEN EVENTUALLY
BECOMING CENTERED WEST OF THE REGION BY LATE IN THE WEEKEND. AT THE
SURFACE...ATLANTIC HIGH PRESSURE WILL RETROGRADE AS WELL...WITH ITS
AXIS TAKING ON A WEST-EAST ORIENTATION JUST SOUTH OF THE REGION.
OVERALL...THIS PATTERN WILL FAVOR MORE TYPICAL SUMMERTIME CONDITIONS
WITH ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS IN THE
AFTERNOON/EARLY EVENING EACH DAY...ALTHOUGH COVERAGE SHOULD BE A BIT
LOWER BY LATE WEEKEND AS A DRIER NORTHWEST FLOW DEVELOPS ALOFT.
TEMPERATURES WILL GRADUALLY WARM EACH DAY BENEATH RISING HEIGHTS
ALOFT...STAYING ABOVE NORMAL THROUGH THE LONG TERM PERIOD.

&&

.AVIATION /00Z TUESDAY THROUGH SATURDAY/...
THUNDERSTORMS WILL IMPACT KSAV TO START THE 00Z TAF PERIOD.
THUNDERSTORMS ARE NOT EXPECTED TO IMPACT KCHS. OTHERWISE...VFR.

EXTENDED AVIATION OUTLOOK...BRIEF FLIGHT RESTRICTIONS ARE
POSSIBLE IN MAINLY SCATTERED AFTERNOON/EARLY EVENING SHOWERS AND
THUNDERSTORMS.

&&

.MARINE...
TONIGHT...S/SE WINDS 10-15 KT WITH A FEW GUSTS TO 20 KT WILL
VEER TOWARD THE SW OVERNIGHT. SEAS WILL AVERAGE 2-3 FT WITHIN
NEARSHORE WATERS AND 3-4 FT BEYOND 20 NM.

TUESDAY THROUGH SATURDAY...SOUTH TO SOUTHWEST WINDS WILL PREVAIL
THROUGH THE PERIOD AS THE REGION REMAINS ALONG THE WESTERN PERIPHERY
OF ATLANTIC HIGH PRESSURE. WINDS WILL GENERALLY AVERAGE 10-15
KT...POSSIBLY A BIT HIGHER AT NIGHT WITH WEAK NOCTURNAL SURGING AND
ALONG THE LAND/SEA INTERFACE WITH THE AFTERNOON SEA BREEZE. SEAS
WILL AVERAGE 2-4 FT. BOTH WINDS AND SEAS LOOK TO REMAIN BELOW SMALL
CRAFT ADVISORY THRESHOLDS.

&&

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

&&

$$
SYNOPSIS...
NEAR TERM...SPR
SHORT TERM...
LONG TERM...
AVIATION...SPR
MARINE...SPR


USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.