203
FXUS62 KCAE 190053
AFDCAE
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE COLUMBIA SC
853 PM EDT THU JUN 18 2026
WHAT HAS CHANGED
UPDATED KEY MESSAGE. 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 EVENING INTO FRIDAY MORNING.
OVERVIEW: THE REMNANTS OF ARTHUR CONTINUE TO MOVE NORTHEASTWARD
TOWARD THE FA THIS EVENING. DEEP MOISTURE REMAINS IN PLACE WITH
SURFACE DEWPOINTS IN THE LOW TO MID 70S AND PWAT'S NOW OVER 2"
ACROSS THE CWA. THE FIRST WAVE OF STORMS HAS BY AND LARGE CLEARED
THE AREA, AND WE ARE NOW TURNING OUR ATTENTION TO CENTRAL GA. THIS
NEXT LINE OF STORMS WILL CARRY WITH IT A SLIGHTLY ELEVATED TORNADO
THREAT, PARTICULARLY DUE TO A STRENGTHENING WIND FIELD. AS HAS BEEN
ADVERTISED, THE POTENTIAL HEAVY RAINFALL THREAT ALSO CONTINUES THIS
EVENING INTO EARLY FRIDAY MORNING, WHEN VERY EFFICIENT RAIN RATES
ARE EXPECTED AND ISOLATED FLASH FLOODING WILL BE POSSIBLE. WIND
GUSTS OVERNIGHT COULD NEAR 35-45 MPH, 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 NOW 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: THIS EVENING AND OVERNIGHT IS WHEN KINEMATICS
IMPROVE AS THE REMNANT CORE OF ARTHUR MOVES IN WITH ITS LOW LEVEL
CIRCULATION. THESE IMPROVED WIND FIELDS CAN ALREADY BEEN SEEN FROM
UPSTREAM VAD PROFILES, WHICH SHOULD BRING IN 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: 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/EC
AVIATION...ND
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