454
FXUS62 KCHS 221219
AFDCHS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
719 AM EST SAT FEB 22 2025
SYNOPSIS
HIGH PRESSURE WILL PREVAIL ACROSS THE REGION THROUGH SUNDAY. A
WEAK DISTURBANCE WILL PASS TO OUR SOUTH SUNDAY NIGHT INTO
MONDAY, FOLLOWED BY HIGH PRESSURE THROUGH WEDNESDAY. A COLD
FRONT SHOULD MOVE THROUGH ON THURSDAY.
NEAR TERM /THROUGH TONIGHT/
FOR TODAY: FLAT RIDGING OR ZONAL FLOW ALOFT WILL PERSIST THE
BULK OF THE DAY, BEFORE A FAST MOVING SHORT WAVE FOUND IN THE
MID MISSISSIPPI VALLEY EARLY ON, CROSSES OVER THE SOUTHERN
APPALACHIANS LATE. AT THE SURFACE, HIGH PRESSURE INITIALLY OVER
VIRGINIA AND NORTH CAROLINA WILL SHIFT EAST INTO THE ATLANTIC
THIS AFTERNOON. AS THIS OCCURS AND THE SHORT WAVE DRAWS CLOSER,
A WEAK TROUGH WILL FORM OUT NEAR THE GULF STREAM. GIVEN THE LACK
OF DEEP MOISTURE AND THE ABSENCE OF FORCING, WE DON'T
ANTICIPATE ANYTHING MORE THAN SCATTERED TO BROKEN CUMULUS AND/OR
STRATOCUMULUS MOVING IN FROM THE SOUTH. THIS OCCURS AS THE LOW
LEVEL FLOW VEERS TO THE SOUTH-SOUTHWEST, AND DRAWS UP SOME
HIGHER MOISTURE AROUND 850 MB INTO THE LOCAL AREA. THIS IS
ALREADY OCCURRING THIS MORNING ACROSS PARTS OF GEORGIA, AND THE
GENERAL TREND WILL BE FOR THESE CLOUDS TO EXPAND IN COVERAGE TO
THE NORTH THROUGH THE DAY. MAX TEMPERATURES WERE DERIVED FROM A
COMBINATION OF THE MOS, NBM, AND LOW LEVEL THICKNESS GUIDANCE,
RESULTING IN UPPER 50S AND LOWER 60S AWAY FROM THE OCEAN.
TONIGHT: THERE IS SOME FORCING THAT DEVELOPS FROM THE SHORT
WAVE AS IT MOVES ACROSS THIS EVENING, BUT ONCE AGAIN MOISTURE
IS SPARSE, AS PWAT IS JUST 0.5 TO 0.75 INCHES AT MOST. SO THE
RISK FOR ANY SHOWER ACTIVITY IS VERY LIMITED, AS IT GENERALLY
LOOKS TO STAY OFFSHORE IN CLOSER PROXIMITY TO THE COASTAL
TROUGH. WITH TIME THAT TROUGH PULLS FURTHER OUT TO SEA ENDING
ANY SMALL RISK FOR SHOWERS, AS HIGH PRESSURE BEGINS TO APPROACH
FROM THE WEST LATE. CLOUD COVER EARLY ON WILL DIMINISH DURING
THE LATE EVENING, LEADING TO MOSTLY CLEAR OR CLEAR SKIES
OVERNIGHT. WITH LIGHT OR CALM WINDS, RADIATIONAL COOLING WILL
BE SUFFICIENT DURING THAT TIME, ENOUGH TO GET LOWS DOWN TO THE
LOWER AND MIDDLE 30S INLAND, UPPER 30S AND LOWER 40S NEAR THE
COAST.
THERE ARE SOME SIGNALS OF FOG FORMING LATE, BUT GIVEN
UNFAVORABLE FOG STABILITY INDICES, AND UNFAVORABLE CONDENSATION
PRESSURE DEFICITS, NO MENTION OF FOG HAS BEEN INCLUDED IN THE
FORECAST AT THIS TIME.
SHORT TERM /SUNDAY THROUGH TUESDAY/
SUNDAY: WEAK MID-LEVEL TROUGHING WILL BE LOCATED OFF THE EAST COAST
IN THE MORNING. THIS WILL LEAD TO NW FLOW OVERHEAD. ADDITIONALLY, A
SHORTWAVE WILL BE LOCATED OVER THE SOUTHERN PLAINS. IT'LL SHIFT EAST
AS TIME PROGRESSES, BECOMING LOCATED OVER THE SOUTHEAST U.S. LATE AT
NIGHT. WEAK SURFACE TROUGHING LOCATED JUST OFF OUR COAST IN THE
MORNING WILL BE PUSHED AWAY BY HIGH PRESSURE BUILDING IN FROM THE
WEST. THE HIGH IS EXPECTED TO PASS TO OUR NORTH LATE IN THE DAY,
THEN WEAKEN AS IT MOVES OFFSHORE OVERNIGHT. ADDITIONALLY, A STORM
SYSTEM WILL BE IMPACTING THE GULF STATES DURING THE DAY, SHIFTING
EASTWARD WITH TIME. IT'LL START IMPACTING THE SOUTHEAST U.S. LATE AT
NIGHT. THE HIGH WILL BRING DRY CONDITIONS DURING THE DAY AND INTO
THE EVENING. MOISTURE WILL THEN QUICKLY INCREASE FROM THE SOUTH
AFTER MIDNIGHT. PWATS SHOULD PEAK ~1" JUST SOUTH OF MCINTOSH COUNTY
LATE AT NIGHT. LIKEWISE, ALL OF THE SYNOPTIC MODELS HAVE ISOLATED
SHOWERS SOUTH OF THE GA/SC BORDER DURING THAT TIME PERIOD. HENCE, WE
WENT WITH SLIGHT CHANCE POPS IN THIS LOCATION WITH MINIMAL QPF. AS
FOR TEMPERATURES, WITH A DECENT AMOUNT OF SUN, HIGHS SHOULD RANGE
FROM AROUND 60 DEGREES TO MAYBE THE MIDDLE 60S, EXCEPT COOLER AT THE
BEACHES. INCREASING CLOUDS OVERNIGHT WILL LIMIT LOW TEMPERATURES TO
THE MID 30S INLAND TO THE MID 40S ALONG THE BEACHES.
MONDAY: THE MID-LEVELS WILL CONSIST OF A SHORTWAVE OVER THE
SOUTHEAST U.S. IN THE MORNING, AND A SECOND SHORTWAVE OVER THE LOWER
MS VALLEY. THE FIRST SHORTWAVE SHOULD SLOWLY SHIFT OFFSHORE BY THE
EVENING, MOVING FURTHER AWAY OVERNIGHT. THOUGH, THE SECOND SHORTWAVE
WILL BE SLOWER TO MOVE EAST, BECOMING LOCATED TO OUR SOUTH AND OVER
FL OVERNIGHT. AT THE SURFACE, A STORM SYSTEM WILL BE IMPACTING THE
SOUTHEAST U.S. IN THE MORNING. IT'S NORTHERN ENERGY SHOULD SHIFT
OFFSHORE THROUGH THE AFTERNOON, WHILE IT'S SOUTHERN ENERGY REMAINS
OVER FL INTO THE OVERNIGHT. THERE ARE SOME DIFFERENCES IN THE MODELS
REGARDING THE EVOLUTION OF THIS STORM SYSTEM, BUT ALL OF THE MODELS
HAVE THE MAIN ENERGY AND RAINFALL REMAINING JUST TO OUR SOUTH. BUT
THEY DO POINT TO AT LEAST ISOLATED TO MAYBE SCATTERED SHOWERS ACROSS
MOST OF OUR AREA IN THE MORNING, WITH SHOWERS SHIFTING TOWARDS OUR
COASTAL COUNTIES IN THE AFTERNOON. WE HAVE AT LEAST SLIGHT CHANCE
POPS WITH MINIMAL QPF. BUT BOTH OF THESE MAY NEED TO BE INCREASED
WITH FUTURE FORECASTS. HIGH PRESSURE BUILDING IN FROM THE WEST WILL
BRING DRY CONDITIONS IN THE EVENING AND OVERNIGHT. HIGHS MAY RISE TO
NEAR NORMAL, GENERALLY THE MID 60S, EXCEPT COOLER AT THE BEACHES.
WITH MOSTLY CLEAR SKIES AND CALM WINDS, LOWS WILL BE IN THE UPPER
30S INLAND TO THE MID 40S ALONG THE BEACHES.
TUESDAY: A SHORTWAVE WILL BE LOCATED TO OUR SOUTH, OVER FL, IN THE
MORNING. IT'S EXPECTED TO MOVE OFFSHORE AS THE DAY PROGRESSES. THIS
WILL YIELD NORTHWEST FLOW OVERHEAD. A STORM SYSTEM WILL BE LOCATED
TO OUR SOUTH AND SOUTHEAST IN THE MORNING, AND SHIFTING AWAY INTO
THE AFTERNOON. HIGH PRESSURE WILL BUILD OVER THE GULF STATES INTO
THE AFTERNOON, WITH ITS EASTERN PERIPHERY STRETCHING INTO OUR AREA.
THE HIGH WILL BRING MOSTLY SUNNY SKIES AND WESTERLY SURFACE WINDS.
THIS SHOULD LEAD TO HIGH TEMPERATURES ABOVE NORMAL, MAINLY IN THE
LOWER 70S, EXCEPT COOLER AT THE BEACHES.
LONG TERM /TUESDAY NIGHT THROUGH FRIDAY/
HIGH PRESSURE WILL BRING DRY CONDITIONS THROUGH WEDNESDAY. A COLD
FRONT SHOULD BRING A ROUND OF SHOWERS ON THURSDAY. HIGH PRESSURE AND
DRY CONDITIONS RETURN ON FRIDAY. TEMPERATURES SHOULD BE ABOVE NORMAL
WEDNESDAY AND THURSDAY, THEN FALLING TO NEAR NORMAL ON FRIDAY.
AVIATION /12Z SATURDAY THROUGH WEDNESDAY/
KCHS/KJZI/KSAV: VFR INTO EARLY SUNDAY MORNING.
EXTENDED AVIATION OUTLOOK: A WEAK DISTURBANCE WILL PASS TO OUR SOUTH
SUNDAY NIGHT INTO MONDAY, BRINGING LOW PROBABILITIES OF FLIGHT
RESTRICTIONS, MAINLY TO OUR GA COUNTIES. OTHERWISE, VFR SHOULD
PREVAIL THE REST OF THE TIME.
MARINE
TODAY AND TONIGHT: RATHER QUIET MARINE CONDITIONS WILL OCCUR,
WITH WINDS AND SEAS FAR BENEATH ANY ADVISORY LEVELS. HIGH
PRESSURE TO THE NORTH OF THE WATERS THIS MORNING WILL PULL EAST
INTO THE ATLANTIC THIS AFTERNOON, AS A WEAK INVERTED TROUGH
FORMS NEAR THE GULF STREAM. THAT TROUGH DOES SHARPEN SOME THIS
EVENING, BUT MOVES EAST THEREAFTER, AS HIGH PRESSURE STARTS TO
PUSH INTO THE SOUTHEAST. WINDS WILL START FROM THE NE AT LESS
THAN 10 OR 15 KT THIS MORNING, BECOMING E OR SE AT 10 KT OR LESS
LATE TODAY, BEFORE SHIFTING TO THE NW AT 10 OR MAYBE 15 KT LATE
TONIGHT IN WAKE OF THE DEPARTING INVERTED TROUGH. SEAS WILL
AVERAGE JUST 2 OR 3 FEET THROUGHOUT.
SUNDAY: WEAK SURFACE TROUGHING LOCATED JUST OFF OUR COAST IN THE
MORNING WILL BE PUSHED AWAY BY HIGH PRESSURE BUILDING IN FROM THE
WEST. THE HIGH IS EXPECTED TO PASS TO OUR NORTH LATE IN THE DAY,
THEN WEAKEN AS IT MOVES OFFSHORE OVERNIGHT. ADDITIONALLY, A STORM
SYSTEM WILL BE IMPACTING THE GULF STATES DURING THE DAY, SHIFTING
EASTWARD WITH TIME. IT'LL START IMPACTING THE SOUTHEAST U.S. LATE AT
NIGHT. THOUGH, NO MARINE HEADLINES ARE EXPECTED.
MONDAY: A STORM SYSTEM WILL BE IMPACTING THE SOUTHEAST U.S. IN THE
MORNING. IT'LL SHIFT OFFSHORE INTO THE AFTERNOON. HIGH PRESSURE WILL
BUILD IN FROM THE WEST IN THE EVENING AND OVERNIGHT.
TUESDAY AND WEDNESDAY: HIGH PRESSURE WILL PREVAIL.
CHS WATCHES/WARNINGS/ADVISORIES
GA...NONE.
SC...NONE.
MARINE...NONE.
NEAR TERM...
SHORT TERM...
LONG TERM...
AVIATION...
MARINE...
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page