776
FXUS62 KCHS 190558
AFDCHS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
158 AM EDT TUE MAY 19 2026
WHAT HAS CHANGED
ALL KEY MESSAGES AND SECTIONS WERE UPDATED.
KEY MESSAGES
- 1) RAIN CHANCES LIKELY TO INCREASE LATE IN THE WEEK, THOUGH NO
HAZARDOUS WEATHER IS ANTICIPATED AT THIS TIME.
DISCUSSION
KEY MESSAGE 1: RAIN CHANCES LIKELY TO INCREASE LATE IN THE
WEEK, THOUGH NO HAZARDOUS WEATHER IS ANTICIPATED AT THIS TIME.
ATLANTIC HIGH PRESSURE CENTERED WELL OFFSHORE WILL MAINTAIN ITS
INFLUENCE ON THE REGION TODAY. SUBSIDENCE WILL BEGIN TO INCREASE
ALOFT LATER TODAY AS THE PRONOUNCED TROPICAL UPPER TROPOSPHERIC
TROUGH (TUTT) POSITIONED NEAR 29N/73W PRIOR TO DAYBREAK DRAWS
CLOSER TO THE SOUTHEAST U.S. COAST AND CONTINUES TO SLIDES WEST
BENEATH THE SUBTROPICAL ANTICYCLONE CENTERED WELL EAST OF CAPE
HATTERAS. THIS COUPLED WITH LOW 850 HPA THETA-E WILL KEEP RAIN-
FREE CONDITIONS IN PLACE EVEN AS A PURE SEA BREEZE CIRCULATION
MOVES STEADILY INLAND THROUGH THE AFTERNOON AND EVENING. HIGHS
WILL CONTINUE TO RUN A FEW DEGREES ABOVE NORMAL WITH HIGHS
POISED TO PEAK IN THE LOWER 90S INLAND TO THE MID-UPPER 70S AT
THE BEACHES. SIMILAR TO THE PAST FEW DAYS, THE BOUNDARY LAYER
WILL LIKELY NOT COMPLETELY DECOUPLE UNTIL WELL AFTER MIDNIGHT
AS THE SEA BREEZE MOVES INTO THE SOUTHERN MIDLANDS, CSRA AND
EAST-CENTRAL GEORGIA. LIGHT WINDS AND MOSTLY CLEAR SKIES WILL
SUPPORT MODEST RADIATIONAL COOLING WITH LOWS RANGING FROM THE
MID 60S INLAND TO THE LOWER 70S AT THE BEACHES. ANOTHER ROUND OF
SHALLOW GROUND FOG APPEAR LIKELY AWAY FROM THE BEACHES, BUT
IMPACTS SHOULD BE MINIMAL WITH MODELS SHOW RATHER HIGH 1000 HPA
CONDENSATION PRESSURE DEFICITS.
SFC HIGH PRESSURE HOLDS TIGHT ACROSS THE REGION THROUGH
WEDNESDAY. ALLOWING QUIET CONDITIONS TO PREVAIL. AS NOTED IN
DAYS PAST, SHOULD SEE THE UPPER LEVEL PATTERN SHIFT AS WE HEAD
INTO THE LATTER HALF OF THE WEEK, WHEN A SHORTWAVE TROUGH
DEEPENS ACROSS THE NORTHERN PLAINS. MEANWHILE, AT THE SFC, WILL
SEE A COLD FRONT EXTENDING FROM MAINE TO TEXAS DIVE
SOUTHEASTWARD AHEAD OF THIS FEATURE, CAUSING RAIN CHANCES TO
RETURN TO THE FORECAST.
UNFORTUNATELY, MODEL GUIDANCE AND CERTAINTY REMAIN RATHER POOR
AT THIS TIME, KEEPING OVERALL CONFIDENCE IN RAINFALL OCCURRENCE
AND TIMING LOW. LATEST TRENDS WOULD FAVOR A STRONGER RIDGE OVER
THE ATLANTIC, RESULTING IN THE AFOREMENTIONED FRONT AND FORCING
STAYING FURTHER WEST AND NORTH OF OUR AREA. AS SUCH, THIS
SCENARIO WOULD ENTAIL SEEING LESS PRECIPITATION ACROSS OUR AREA
THAN PREVIOUSLY FORECASTED. IN FACT, CURRENT ENSEMBLE PROBABILITIES
FOR SEEING RAINFALL ACCUMULATIONS GREATER THAN ONE INCH THROUGH
SATURDAY HAVE NOW DROPPED TO LESS THAN 25% (WITH THE GREATEST
THREAT STILL INLAND) - WHEREAS YESTERDAY PROBABILITIES RANGED
FROM 20-60%. CERTAINLY SOMETHING TO KEEP AN EYE ON, AS MODEL
RUNS COULD STILL SHIFT IN THE COMING DAYS. OTHERWISE, EXPECT THE
SEVERE POTENTIAL WITH ANY SHOWER/STORM TO REMAIN LOW, GIVEN THE
LACK OF FORCING AND MOISTURE IN PLACE.
AVIATION /06Z TUESDAY THROUGH SATURDAY/
19/06Z TAF DISCUSSION:
KCHS/KJZI/KSAV: VFR. ANOTHER ROUND OF SHALLOW GROUND FOG COULD
DEVELOP AT ALL THREE TERMINALS THROUGH DAYBREAK. THE FOG SHOULD
NOT IMPACT OPERATIONS GIVEN IT IS LIKELY SHALLOW NATURE, BUT
VSBYS AT KJZI AND KSAV (UNTIL THE OBSERVER COMES ON DUTY) COULD
YIELD SOME SIGNIFICANT SWINGS IN VSBYS AS FOG LAYERS MEANDER AT
NEAR THE SENSORS. FOR NOW, NO MENTION OF SUB-VFR VSBYS WERE
INCLUDED, BUT TRENDS WILL BE MONITORED. GUSTY WINDS WILL AGAIN
ACCOMPANY THE AFTERNOON SEA BREEZE.
EXTENDED AVIATION OUTLOOK: THERE ARE NO HIGH CONFIDENCE
CONCERNS.
MARINE
THROUGH TONIGHT: QUIET CONDITIONS WILL PERSIST WITH THE REGION
POSITIONED ALONG THE WESTERN FLANKS OF ATLANTIC HIGH PRESSURE
CENTERED WELL OFFSHORE. EAST/SOUTHEAST WINDS WILL PREVAIL WITH
SPEEDS LESS THAN 15 KT, ALTHOUGH SOME LOCAL ENHANCEMENT ALONG
THE LAND/SEA INTERFACE AND CHARLESTON HARBOR WILL LIKELY OCCUR
WITH THE SEA BREEZE. SEAS WILL AVERAGE 2-4 FT.
WEDNESDAY THROUGH FRIDAY: NO MARINE CONCERNS ARE EXPECTED. HIGH
PRESSURE TO THE EAST WILL DRIVE ONSHORE EAST-SOUTHEASTERLY FLOW
EACH DAY, WITH WIND SPEEDS MOSTLY TOPPING OUT IN THE 10-15 KNOT
RANGE. EACH AFTERNOON AND EVENING THERE COULD BE SOME LOCAL
ENHANCEMENT ALONG THE LAND/SEA INTERFACE WITH THE DIURNAL SEA
BREEZE. SEAS SHOULD AVERAGE 2-4 FEET THROUGH THE PERIOD.
CHS WATCHES/WARNINGS/ADVISORIES
GA...NONE.
SC...NONE.
MARINE...NONE.
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