Area Forecast Discussion
Issued by NWS Charleston, SC

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FXUS62 KCHS 250530
AFDCHS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
130 AM EDT FRI JUL 25 2014

.SYNOPSIS...
AN ATLANTIC RIDGE OF HIGH PRESSURE WILL REMAIN SOUTH OF THE AREA
INTO EARLY NEXT WEEK...WITH A WEAK TROUGH OF LOW PRESSURE
PREVAILING INLAND. A COLD FRONT COULD APPROACH LATE MONDAY AND
BECOME STATIONARY SOUTH AND SOUTHEAST OF THE AREA DURING THE
MIDDLE OF NEXT WEEK.

&&

.NEAR TERM /UNTIL 6 AM THIS MORNING/...
SHORT WAVE MOVING THROUGH EAST/NE SC WILL CONTINUE TO CAUSE SOME
CONVECTION OVERNIGHT...MAINLY IN NORTHERN CHARLESTON AND BERKELEY
COUNTIES. OTHERWISE...WARM AND MUGGY WITH TEMPS HESITANT TO FALL
ANY LOWER THAN THE MID OR UPPER 70S OVER THE VAST MAJORITY OF THE
CWFA.

&&

.SHORT TERM /6 AM THIS MORNING THROUGH SUNDAY/...
A WEAK FRONT/SURFACE TROUGH WILL BE STALLED NEAR TO JUST NORTHWEST
OF THE AREA THROUGH SATURDAY...THEN LIFT NORTHWARD AND DISSIPATE
BY SUNDAY. A BROAD UPPER TROUGH WILL BE OVER THE REGION FRIDAY AND
INTO SATURDAY. BY SUNDAY...THE UPPER TROUGH IS EXPECTED TO FLATTEN
AND MOVE EAST WAS A DEEP LAYER RIDGE TRIES TO BUILD FROM THE WEST.

DEEP LAYER MOISTURE WILL BE PLENTY SUFFICIENT THROUGH AT LEAST
SATURDAY...WITH PWS 1.8 TO 2.0 INCHES. HOWEVER ONLY REALLY FORCING
FOR CONVECTION WILL BE LOWER LEVEL BOUNDARIES/SEA BREEZE. THINK THE
BEST COVERAGE WILL BE FRIDAY...FROM I-95 EASTWARD TOWARD THE
COAST...AS MAIN STEERING FLOW WILL BE WEST-SOUTHWEST. HAVE KEPT MID
RANGE CHANCE POPS FOR FRIDAY AFTERNOON AND EARLY EVENING. FOR
SATURDAY...SLIGHTLY LOWER MOISTURE VALUES AND EVEN LESS OF AN UPPER
TROUGH...SHOULD TRANSLATE TO SLIGHTLY LOWER POPS...WITH A FOCUS
AGAIN JUST INLAND TO BACK TOWARD THE COAST. BY SUNDAY...DEEP LAYER
MOISTURE WILL GO DOWN A BIT AS MEAN RH VALUES FALL BELOW 50%...AND
ALONG WITH A BUILDING DEEP LAYER RIDGE...EXPECT ONLY ISOLATED MAINLY
AFTERNOON CONVECTION.

TEMPERATURES NEAR NORMAL FRIDAY...THEN MODERATING TO ABOVE NORMAL
SATURDAY AND ESPECIALLY SUNDAY. GUIDANCE CONTINUES TO SHOW MID 90S
FOR HIGHS BOTH SATURDAY AND SUNDAY.

&&

.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
A DEEP LAYERED GYRE OVER OR NEAR SOUTHERN HUDSON BAY IN CANADA WILL
CIRCULATE OCCASIONAL SHORT WAVES THROUGH THE GREAT LAKES AND OHIO
VALLEY...WHICH IN TURN WILL CARVE OUT A BROAD AND FAIRLY WELL
AMPLIFIED TROUGH ACROSS THE EASTERN HALF OF THE COUNTRY DURING THE
EARLY AND MIDDLE PARTS OF NEXT WEEK. THIS IS DEFINITELY NOT A
SUMMER-LIKE PATTERN...AND IT WILL SEND AN UNUSUAL LATE JULY COLD
FRONT INTO THE AREA FROM THE NW LATER MONDAY AND EARLY TUESDAY.
SURPRISINGLY IT LOOKS LIKE THERE IS ENOUGH NW PUSH BEHIND THE
FRONT TO SEND IT THROUGH THE AREA...BEFORE IT STALLS OUT NOT FAR
TO THE SE AND SOUTH FOR THE MIDDLE OF THE WEEK. RAIN CHANCES WILL
CLIMB MONDAY AND TUESDAY IN CONJUNCTION WITH THE FRONT...MAINLY IN
THE 20-40 PERCENT RANGE. PROVIDED THE FRONT CLEARS THE AREA RAIN
CHANCES ARE NO MORE THAN 20 PERCENT WEDNESDAY...THEN 20-30 PERCENT
NEXT THURSDAY AS THE FRONT STARTS TO TREK BACK NORTH.
COMPRESSIONAL HEATING OUT AHEAD OF THE FRONT ALLOWS FOR ABOVE
NORMAL TEMPS MONDAY...WITH ONLY VERY MINIMAL COOL ADVECTION TO
DROP READINGS SLIGHTLY BELOW NORMAL TUESDAY THROUGH THURSDAY.

&&

.AVIATION /06Z FRIDAY THROUGH TUESDAY/...
KCHS...LINGERING CONVECTION OVERNIGHT WITH A SHORT WAVE WILL STAY
PRETTY FAR NORTH/NE OF THE TERMINAL. THUS VFR WEATHER WILL PREVAIL
INTO FRIDAY AFTERNOON. HOWEVER...CONVERGENCE WILL BECOME ENHANCED
DUE TO THE INTERACTION OF THE SEA BREEZE AND NEARBY PROXIMITY TO
THE INLAND TROUGH...THUS WE HAVE INTRODUCED VCTS FROM 19-24Z.
DEPENDING UPON HOW TRENDS BEAR OUT...FLIGHT RESTRICTIONS ARE
CERTAINLY POSSIBLE DURING THIS TIME. CONVECTION DIES OFF QUICKLY
IN THE EVENING AND VFR CONDITIONS WILL AGAIN PREVAIL.

KSAV...NO IMPACTS AT THE TERMINAL OVERNIGHT NOR THROUGH MUCH OF
FRIDAY. PROBABILITIES OF CONVECTION DURING THE MID AFTERNOON INTO
THE EARLY EVENING ARE TOO LOW TO INCLUDE ANY MENTION OF AT THIS
STAGE. THUS FOR NOW PREVAILING VFR CONDITIONS THROUGH 06Z SATURDAY.

EXTENDED AVIATION OUTLOOK...MAINLY VFR. A COLD FRONT COULD MOVE
INTO THE AREA BY TUESDAY...BUT CONFIDENCE ON THE TIMING AND
STRENGTH OF THIS FRONT IS LOW...GIVEN THAT FRONTS TEND TO STRUGGLE
TO MOVE INTO OUR REGION THIS TIME OF YEAR.

&&

.MARINE...
OVERNIGHT...A TROUGH OF LOW PRESSURE INLAND WILL PROGRESS A LITTLE
TOWARD THE COAST. GOOD MIXING ALONG THE COAST AND NEAR SHORE
WATERS WITH 15-20 KT COMMON. NOCTURNAL JET WILL SLIP OFF THE COAST
LATER TONIGHT WITH SPEEDS DIMINISHING LATE NEAR SHORE. SEAS
BETWEEN 3 AND 4 FT OVER THE WATERS TONIGHT.

NO HIGHLIGHTS EXPECTED THROUGH MUCH OF THE WEEKEND AS THE AREA
REMAINS BETWEEN ATLANTIC HIGH PRESSURE TO THE EAST AND A WEAK TROUGH
OF LOW PRESSURE WELL INLAND. THIS WILL PRODUCE SOUTHWEST WINDS OF
GENERALLY 15 KT OR LESS AND SEAS 2-4 FEET. BY SUNDAY NIGHT AND
MONDAY...THE PRESSURE GRADIENT BEGINS TO TIGHTEN/INCREASE AS SURFACE
PRESSURES LOWER OVER THE MID ATLANTIC AND SOUTHEAST STATES...AND
HIGHER PRESSURE HOLDS ON OVER THE ATLANTIC. CURRENT FORECAST
INCREASES WINDS INTO THE 15-20 KT RANGE WITH SEAS APPROACHING 5 FT
OFFSHORE THROUGH MONDAY NIGHT. A COLD FRONT COULD MOVE INTO THE
WATERS TUESDAY...VEERING WINDS TO LIGHT NORTHERLY.

&&

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

&&

$$

NEAR TERM...
SHORT TERM...RFM
LONG TERM...
AVIATION...
MARINE...






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