609
FXUS62 KCAE 202354
AFDCAE
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE COLUMBIA SC
754 PM EDT WED MAY 20 2026
WHAT HAS CHANGED
SOME LINGERING CONVECTION MAY IMPACT UPPER CSRA THIS EVENING.
AVIATION DISCUSSION UPDATED FOR 00Z TAF ISSUANCE.
KEY MESSAGES
- 1. LINGERING CONVECTION JUST WEST OF CWA MAY IMPACT UPPER
CSRA THIS EVENING.
- 2. UNCERTAINTY IN TEMPERATURES FRIDAY AND THIS WEEKEND.
- 3. RAIN CHANCES INCREASE LATE WEEK ONWARD.
DISCUSSION
KEY MESSAGE 1: LINGERING CONVECTION JUST WEST OF CWA MAY IMPACT
UPPER CSRA THIS EVENING.
LATE AFTERNOON CONVECTION ACROSS CENTRAL AND NORTHEAST GA HAS
GRADUALLY MOVED EASTWARD TOWARD THE UPPER CSRA THIS EVENING.
CANNOT RULE OUT A FEW SHOWERS OR ISOLATED STORM IMPACTING
LINCOLN AND MCCORMICK COUNTIES THIS EVENING BEFORE CONVECTION
WANES AS THE ATMOSPHERE STABILIZES. WILL INCLUDE A FEW HOURS OF
POPS TO ACCOUNT FOR THIS. OTHERWISE, SKIES SHOULD AGAIN BE
MOSTLY CLEAR OVERNIGHT WITH ANOTHER ROUND OF POSSIBLE PREDAWN
FOG/STRATUS.
KEY MESSAGE 2: UNCERTAINTY IN TEMPERATURES FRIDAY AND THIS
WEEKEND.
HIGHS TODAY AND THURSDAY WILL REMAIN ABOVE NORMAL BUT STILL
UNDER ANY HEAT ADVISORY THRESHOLDS.
AS HIGH PRESSURE MOVES INTO THE NORTHEAST LATE THIS WEEK, COLD
AIR DAMMING DEVELOPS OVER THE MID-ATLANTIC STATES PUSHING A
SURFACE BOUNDARY DOWN INTO THE CAROLINAS. THIS WOULD LEAD TO A
LARGE TEMPERATURE GRADIENT OVER THE FORECAST AREA. HOWEVER
BLENDED GUIDANCE HAS NEARLY THE ENTIRE FORECAST AREA IN THE 80S
OR LOW 90S FOR FRIDAY AND SATURDAY. THIS DETERMINISTIC GUIDANCE
MAY NOT BE PROPERLY SHOWING THE UNCERTAINTY OF WHERE THAT
BOUNDARY MAY SET UP. A PORTION OF THE FORECAST AREA COULD
STRUGGLE TO RISE OUT OF THE MID 70S FRIDAY AND POSSIBLY
SATURDAY GIVEN THAT THE WEDGE BOUNDARY TYPICALLY REMAINS IN
PLACE LONGER THAN MODELS SHOW. CONFIDENCE IN THE WEDGE HOLDING
IS INCREASED BY THE EXPECTATION OF RAIN FALLING THROUGH THE COOL
LOWER LEVELS.
KEY MESSAGE 3: RAIN CHANCES INCREASE LATE WEEK ONWARD.
UPPER RIDGING WILL SHIFT SLIGHTLY EASTWARD THURSDAY AND FRIDAY
ALLOWING DEEPER MOISTURE AND SHORTWAVE ENERGY TO MOVE OVER THE
FORECAST AREA. INCREASED MOISTURE AND BETTER UPPER SUPPORT
SHOULD ALLOW CONVECTION TO DEVELOP EACH AFTERNOON AS THE AIR
MASS BECOMES CONDITIONALLY UNSTABLE. FRIDAY AND FRIDAY NIGHT MAY
BE PARTICULARLY ACTIVE AS THE WEDGE BOUNDARY DISCUSSED IN KM1
PUSHES INTO THE AREA FROM THE NORTH AND A SERIES OF SHORTWAVES
MOVES OVER THE REGION. THIS SHOULD HELP SUSTAIN CONVECTION PAST
THE DIURNALLY FAVORED TIMEFRAME AND INTO THE OVERNIGHT PERIOD.
REFS MEAN SBCAPE VALUES RISE TO 750 TO 1250 J/KG EACH AFTERNOON.
WITH WEAK INSTABILITY AND IN A WEAKLY SHEARED ENVIRONMENT WE
SHOULD SEE THUNDERSTORMS DEVELOP BUT WE EXPECT THEM TO BE SUB-
SEVERE.
THE DEEPEST MOISTURE APPEARS TO MOVE INTO THE REGION ON SATURDAY
AS MOISTURE TRANSPORT STRENGTHENS OVER THE WEDGE BOUNDARY. THIS
SHOULD LEAD TO WIDESPREAD SHOWERS AND THUNDERSTORMS. DEEP LAYER
SHEAR WILL BE A LITTLE STRONGER SATURDAY, WITH SOME HELICITY
ENHANCEMENT ALONG THE FRONT. THERE IS A QUESTION AS TO HOW
UNSTABLE THE ENVIRONMENT WILL BE GIVEN THE EXPECTED WIDESPREAD
RAINFALL AND CLOUD COVER, BUT THERE WILL BE SOME POTENTIAL FOR
ORGANIZED CONVECTION AND SEVERE WEATHER SATURDAY AFTERNOON.
THE DEEPEST MOISTURE MOVES OUT OF THE REGION ON SUNDAY WITH
UPPER RIDGING BUILDING BACK IN OVER THE SOUTHEAST. PWAT VALUES
REMAIN ABOVE NORMAL ALLOWING SHOWERS AND THUNDERSTORMS TO
DEVELOP EACH AFTERNOON COINCIDING WITH DAYTIME HEATING. WITH
STRONGER RIDGING OVER THE AREA AND THE WEDGE BOUNDARY SHIFTING
BACK TO THE NORTH THERE SHOULD BE LOWER CONVECTIVE COVERAGE
SUNDAY AND EARLY NEXT WEEK COMPARED TO SATURDAY.
AVIATION /00Z THURSDAY THROUGH MONDAY/
VFR CONDITIONS CONTINUE WITH BRIEF RESTRICTIONS POSSIBLE AGAIN
EARLY THURSDAY MORNING.
FEW TO SCT CUMULI WILL DISSIPATE THIS EVENING WITH LIGHT WINDS
AROUND 5-8 KTS GRADUALLY BECOMING SOUTHEASTERLY TO SOUTH-
SOUTHEASTERLY OVER THE NEXT FEW HOURS. WINDS WILL TURN
LIGHT/VARIABLE AFTER SUNSET BENEATH PASSING HIGH CIRRUS. A FEW
ISOLATED SHOWERS ARE POPPING UP WEST OF OUR CWA BUT ARE EXPECTED
TO REMAIN AWAY FROM ALL TERMINALS THIS EVENING. ABUNDANT LOW-
LEVEL MOISTURE WILL SUPPORT ANOTHER ROUND OF PATCHY FOG AND
STRATUS DEVELOPMENT LATE TONIGHT INTO EARLY THURSDAY MORNING,
PRIMARILY AFTER 08-10Z. LATEST HREF AND SREF GUIDANCE CONTINUES
TO INDICATE A 40-60% PROBABILITY OF CIGS BELOW 1,000 FT WITH
THE HIGHEST RISK FOCUSED ACROSS THE SOUTHEASTERN MIDLANDS AND
SOUTHERN CSRA. CLIMATOLOGICALLY FAVORED SITES OF AGS AND OGB
REMAIN THE MOST LIKELY TERMINALS TO EXPERIENCE IFR/LIFR
RESTRICTIONS OVERNIGHT. ANY RESTRICTIONS SHOULD IMPROVE AFTER
12-14Z THURSDAY AS LIGHT SOUTHERLY TO SOUTHWESTERLY WINDS AROUND
3-5 KTS DEVELOP.
SCT CUMULI IS EXPECTED TO REDEVELOP THURSDAY AFTERNOON AHEAD OF
AN APPROACHING FRONT, WITH INCREASING COVERAGE OF SHOWERS AND
THUNDERSTORMS EXPECTED DURING THE AFTERNOON AND EVENING HOURS.
THE BETTER CHANCES FOR SCATTERED CONVECTION APPEAR NEAR THE END
OF THE CURRENT TAF PERIOD, MAINLY AFTER 20-22Z. CONFIDENCE IN
DIRECT TERMINAL IMPACTS REMAINS UNCERTAIN AT THIS TIME, SO ONLY
INCLUDED A VCSH MENTION.
EXTENDED AVIATION OUTLOOK...HIGH LOW LEVEL MOISTURE MAY BRING
MORE ROUNDS OF MORNING RESTRICTIONS FROM FOG/STRATUS INTO THE
WEEKEND. SCATTERED AFTERNOON SHOWERS AND STORMS BECOME POSSIBLE
TOMORROW WITH MORE CHANCES THIS WEEKEND.
CAE WATCHES/WARNINGS/ADVISORIES
SC...NONE.
GA...NONE.
DISCUSSION...23/CJR
AVIATION...ND
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