391
FXUS62 KCAE 190005
AFDCAE
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE COLUMBIA SC
805 PM EDT THU JUN 18 2026
WHAT HAS CHANGED
AVIATION DISCUSSION UPDATED FOR 00Z TAFS.
KEY MESSAGES
- 1. GUSTY WINDS, HEAVY RAINFALL, AND SEVERE WEATHER ARE
POSSIBLE THIS AFTERNOON INTO FRIDAY MORNING.
- 2. A MORE TYPICAL SUMMER-LIKE PATTERN RETURNS FOR THE WEEKEND
INTO NEXT WEEK.
DISCUSSION
KEY MESSAGE 1: GUSTY WINDS, HEAVY RAINFALL, AND SEVERE WEATHER
ARE POSSIBLE THIS AFTERNOON INTO FRIDAY MORNING.
OVERVIEW: THE REMNANTS OF ARTHUR ARE PUSHING ACROSS THE DEEP
SOUTH EARLY THIS AFTERNOON AND ARE EXPECTED TO CONTINUE PUSHING
NORTHEASTWARD TOWARD THE FA THE REMAINDER OF THE DAY AND
TONIGHT. A TIGHTENING PRESSURE GRADIENT IS BRINGING GUSTS OF
20-30 MPH THAT SHOULD CONTINUE THE REMAINDER OF THE AFTERNOON
AND INTO THIS EVENING. DEEP MOISTURE IS ALREADY MAKING ITS
PRESENCE KNOWN WITH SURFACE DEWPOINTS IN THE LOW TO MID 70S AND
PWAT'S NEARING 2.0" ACROSS THE CWA. THE FIRST WAVE OF SCATTERED
SHOWERS AND STORMS ARE ALREADY DEVELOPING IN THE REGION AS A
UNCAPPED AND UNSTABLE AIRMASS IS IN PLACE. A COUPLE STRONG TO
SEVERE STORMS WITH THE MAIN RISK OF DAMAGING WINDS GUSTS WILL BE
POSSIBLE WITH THIS ACTIVITY BEFORE THE MAIN SURGE OF MOISTURE
AND WIDESPREAD RAIN/THUNDERSTORMS MOVES IN THIS EVENING AND
TONIGHT. A STRENGTHENING WIND FIELD WILL AID IN BRINGING AN
INCREASED TORNADO RISK IN THUNDERSTORMS THIS EVENING AND
OVERNIGHT, BUT DAMAGING WIND GUSTS ARE EXPECTED TO REMAIN THE
MAIN SEVERE HAZARD. AS HAS BEEN ADVERTISED, THE MAIN THREAT
CONTINUES TO BE THE POTENTIAL HEAVY RAINFALL THIS EVENING INTO
EARLY FRIDAY MORNING, WHERE VERY EFFICIENT RAIN RATES ARE
EXPECTED AND ISOLATED FLASH FLOODING WILL BE POSSIBLE. WIND
GUSTS OVERNIGHT COULD NEAR 35-45 MPH AS IS STILL SUPPORTED IN
RECENT 12Z GUIDANCE, BUT SOME OF THIS APPEARS TO BE CONVECTIVELY
ENHANCED RATHER THAN PURELY SYNOPTIC WINDS. OVERALL, WITH THE
TIMING OF THE MAIN HAZARDS BEING THIS EVENING AND OVERNIGHT, BE
SURE TO HAVE MULTIPLE WAYS TO RECEIVE WARNINGS.
HEAVY RAINFALL: THERE HAS NOT BEEN A MAJOR CHANGE IN THE
OUTLOOK FOR RAINFALL OUTSIDE OF THE 12Z SUITE OF CAM'S
CONTINUING TO DRIFT THE AXIS OF HEAVIEST RAIN CLOSER TO THE
UPSTATE/NORTHERN MIDLANDS. MAJORITY OF THE CWA REMAINS IN WPC'S
SLIGHT RISK (LEVEL 2 OUT OF 4) FOR EXCESSIVE RAINFALL TODAY INTO
FRIDAY MORNING. AS MENTIONED IN THE OVERVIEW, PWAT'S ARE
ALREADY NEARING 2" AND SHOULD CONTINUE SURGING TOWARD 2.20-2.40"
THIS EVENING AND OVERNIGHT. AS THIS MOISTURE INCREASES WITH THE
APPROACHING UPPER WAVE AND REMNANT LOW LEVEL CIRCULATION MOVING
NEAR THE NORTHERN FA, IVT VALUES ARE NOW FORECAST TO REACH NEAR
CLIMATOLOGICAL MAXIMUM VALUES AS A ROBUST 50-65 KT LLJ MOVES
INTO THE FA. SOME GUIDANCE CONTINUES TO INDICATE THIS LLJ COULD
BE A BIT STRONGER (NEAR 70 KTS) LIKE THE 12Z NAM AND NAM 3K.
THIS IMPRESSIVE LLJ COUPLED WITH THE AFOREMENTIONED PWAT'S, WARM
CLOUD LAYER DEPTHS NEARING 14,000 TO 15,000 FT, AND LINGERING
INSTABILITY SETS THE STAGE FOR THE ADVERTISED EFFICIENT RAIN
RATES. AS MENTIONED ABOVE, THE 12Z SUITE OF GUIDANCE GENERALLY
HAS SHIFTED THE AXIS OF HIGHEST TOTALS A BIT FURTHER NORTH
TOWARD THE UPSTATE AND NORTHERN MIDLANDS, CLOSER TO WHERE THE
REMNANT LOW LEVEL CIRCULATION IS FORECAST TO MOVE. DUE TO THIS,
WIDESPREAD AMOUNTS NEAR 0.50-1.50" STILL SEEMS REASONABLE, BUT
POCKETS OF 2-4" COULD BE IN THE CARDS, ESPECIALLY ALONG AND
NORTH OF THE I-20 CORRIDOR. THESE HIGHER AMOUNTS COULD BE
REALIZED MAINLY WHERE TRAINING OF CONVECTION OCCURS TONIGHT.
THIS AXIS APPEARS HEAVILY DEPENDENT ON THE TRACK OF THE LOW
LEVEL CIRCULATION SO SHIFTS MAY OCCUR STILL. DUE TO THIS, A
FLOOD WATCH STILL DOES NOT SEEM WARRANTED CONSIDERING THE
POTENTIAL SHIFTS IN THE AXIS OF GREATER AMOUNTS AND THAT 2"+
AMOUNTS APPEAR FAIRLY SCATTERED.
SEVERE WEATHER: THE MAIN CHANGE TO THE FORECAST COMES WITH THE
POTENTIAL SEVERE WEATHER THIS EVENING AND OVERNIGHT TONIGHT AS
THE FA IS NOW BISECTED ALONG THE I-20 CORRIDOR BY A SLIGHT RISK
(LEVEL 2 OUT OF 5) FOR SEVERE WEATHER NORTH OF I-20 AND A
MARGINAL RISK (LEVEL 1 OUT OF 5) SOUTH OF HERE. ANY ISOLATED
STRONG TO SEVERE STORM THIS AFTERNOON IS IN A WEAKLY SHEARED
ENVIRONMENT (0-6KM SHEAR UNDER 15 KTS), BUT MLCAPE VALUES ARE
NOW EXCEEDING 1500-2000 J/KG AS STRONG HEATING OCCURS IN IN THE
VERY MOIST AIRMASS. DCAPE VALUES ARE A BIT MARGINAL STILL
(500-800 J/KG), BUT SUFFICIENT FOR PRECIP LOADED DOWNBURST
POTENTIAL (TEI VALUES CURRENTLY NEAR 25) AND THUS BRINGING THE
ISOLATED DAMAGING WIND GUST THREAT INTO THIS EVENING. THIS
EVENING AND OVERNIGHT IS WHEN KINEMATICS IMPROVE AS THE REMNANT
CORE OF ARTHUR MOVES IN WITH IT'S LOW LEVEL CIRCULATION. THESE
IMPROVED WIND FIELDS CAN ALREADY BEEN SEEN FROM THE 17Z VAD
PROFILE IN MOBILE, AL WHERE A LAYER OF 45-50 KT WINDS IS SEEN
FROM ~500M UP TO ~4KM. THIS IS BRINGING 1KM SHEAR VALUES UP TO
NEAR 30 KTS WITH SRH IN THIS LAYER EXCEEDING 150-200 M^2/S^2.
THIS AREA OF ENHANCED LOW LEVEL HELICITY ALONG THE TRACK OF THE
LOW LEVEL CIRCULATION IS EXPECTED TO MOVE IN LATE THIS EVENING
AND OVERNIGHT, BRINGING THE INCREASED RISK FOR A FEW TORNADOS,
MAINLY ALONG/NORTH OF I-20. WITH THE INCREASED SHEAR PROFILES,
CONVECTION COULD ORGANIZE AS CLUSTERS OR POTENTIAL LINEAR
SEGMENTS AS DEPICTED IN RECENT HRRR RUNS. EITHER MODE WILL BRING
THE MAIN HAZARD OF DAMAGING WIND GUSTS TONIGHT, BUT ANY LINEAR
SEGMENTS COULD BRING THE INCREASED TORNADO RISK AS SOUTHWESTERLY
40-45 KT 3KM SHEAR VECTORS WOULD BE FAVORABLY ORIENTED WITH
NORTH-SOUTH LINEAR SEGMENTS FOR THE DEVELOPMENT OF MESOVORTICES.
WIND GUSTS: A TIGHTENING SURFACE PRESSURE GRADIENT THIS
AFTERNOON AND EVENING IS BRINGING GUSTS TO 25-30 MPH BEFORE THE
INCREASING WIND FIELD ALOFT AND AFOREMENTIONED LLJ MAY AID IN
BRING GUSTS OF 35- 45 MPH OVERNIGHT AND INTO EARLY FRIDAY
MORNING. A COUPLE HIGHER GUSTS IN EASTERN SPOTS CANNOT BE RULED
OUT. THE FORECAST SITUATION AROUND THESE GUSTS IS A BIT COMPLEX
AS THESE COULD BE PARTIALLY ATTRIBUTED TO THE MOSTLY INTACT CORE
OF THE REMNANTS FROM ARTHUR, BUT WITH LIKELY ON-GOING
CONVECTION OVERNIGHT, SOME OF THESE WINDS COULD BE CONVECTIVELY
ENHANCED RATHER THAN PURELY SYNOPTIC. ALSO, BUFKIT SOUNDINGS ARE
NOT PARTICULARLY AGGRESSIVE IN TERMS OF MIXING DOWN SOME OF THE
50KT+ LLJ WITH FAIRLY NEUTRAL CONDITIONS NEAR THE SURFACE IN
TERMS OF MIXING. DESPITE THESE COMPLICATIONS, THE SIGNAL REMAINS
ACROSS 12Z HIGH-RES GUIDANCE AND IN THE LATEST HREF WHERE
PROBABILITIES FOR GUSTS GREATER THAN 40 MPH HAS INCREASED
SLIGHTLY TOWARD 40-60%, HIGHEST ALONG AND SOUTH OF THE I-20
CORRIDOR. OVERALL, EXPECT BREEZY WINDS THE REMAINDER OF TODAY
BEFORE STRONGER WINDS WILL BE POSSIBLE TONIGHT INTO FRIDAY
MORNING, ASSOCIATED BOTH WITH CONVECTION AND SYNOPTIC WINDS. ONE
OTHER NOTE WORTH MENTIONING IS SATURATED SOILS FROM THE
DISCUSSED HEAVY RAINFALL MAY MAKE SOME TREES MORE SUSCEPTIBLE TO
FALLING IN STRONGER WINDS TONIGHT.
KEY MESSAGE 2: A MORE TYPICAL SUMMER-LIKE PATTERN RETURNS FOR
THE WEEKEND INTO NEXT WEEK.
AFTER THE REMNANTS OF ARTHUR MOVE OUT OF THE AREA, A FRONT IS
EXPECTED TO SLIDE THROUGH THE FA FRIDAY AFTERNOON/EVENING,
BRINGING ISOLATED TO SCATTERED SHOWER/STORM CHANCES. SLIGHTLY
DRIER CONDITIONS ARE EXPECTED BEHIND THE FRONT THIS WEEKEND, BUT
WITH WARMING TEMPERATURES INTO THE LOW 90S. MULTIPLE
DISTURBANCES ARE FORECAST TO MOVE THROUGH UPPER ZONAL FLOW,
BRINGING A MORE SUMMER- LIKE PATTERN OF DIURNAL THUNDERSTORM
CHANCES AS WE HEAD INTO NEXT WEEK.
AVIATION /00Z FRIDAY THROUGH TUESDAY/
SCATTERED CONVECTION THIS AFTERNOON WRAPPING UP. WIDESPREAD
RAIN TONIGHT WITH RESTRICTIONS DEVELOPING.
THE FIRST ROUND OF SHOWERS AND THUNDERSTORMS HAVE ALL BUT
PUSHED OUT OF THE TERMINALS THIS AFTERNOON. A FEW VICINITY
SHOWERS REMAIN IN AREAS TO OUR NORTH AS THE ACTIVITY BEGINS TO
EXIT AND MOVE INTO NC. WINDS REMAIN GUSTY INTO TONIGHT WITH
GUSTS AROUND 20 KNOTS CONTINUING CONSISTENTLY AND ENHANCED GUSTS
POSSIBLE AT TIMES TONIGHT AS THE REMNANTS OF TS ARTHUR MOVE
INTO THE AREA. THIS WILL LEAD TO STRENGTHENING WINDS ALOFT,
ALTHOUGH SURFACE WINDS SHOULD REMAIN ELEVATED ENOUGH TO PREVENT
LLWS CRITERIA TO BE REACHED. WIDESPREAD MODERATE TO HEAVY RAIN
MOVES OVER THE TERMINALS LATER TONIGHT, ALTHOUGH GENERALLY
GUIDANCE KEEPS VISIBILITY ABOVE 3SM. THERE COULD BE A FEW BRIEF
PERIODS OF IFR VISIBILITIES POSSIBLE, ESPECIALLY AT THE AUGUSTA
TERMINALS. SIMILARLY CEILINGS WILL LIKELY BE PREDOMINANTLY MVFR
BUT MAY DROP TO IFR AT TIMES, LINGERING INTO FRIDAY MORNING.
BREEZY WINDS CONTINUE FRIDAY WITH GUSTS CLOSE TO 15-20 KT,
ALTHOUGH DRIER AIR WILL START TO MOVE INTO THE AREA.
EXTENDED AVIATION OUTLOOK...DIURNALLY DRIVEN CONVECTION CAN BE
ANTICIPATED HEADING INTO THE WEEKEND, ALTHOUGH COVERAGE WILL BE
ISOLATED WITH HIGHER COVERAGE NEXT WEEK.
CAE WATCHES/WARNINGS/ADVISORIES
SC...NONE.
GA...NONE.
DISCUSSION...DH
AVIATION...ND
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