835
FXUS64 KHUN 261638
AFDHUN
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HUNTSVILLE AL
1138 AM CDT THU JUN 26 2025
..NEW NEAR TERM, SHORT TERM
NEAR TERM
(REST OF TODAY AND TONIGHT)
ISSUED AT 1138 AM CDT THU JUN 26 2025
IN THE MID/UPPER-LEVELS, A FLAT SUBTROPICAL RIDGE (INITIALLY
POSITIONED ACROSS THE CENTRAL APPALACHIANS) WILL TRANSLATE
SOUTHEASTWARD OVER THE COURSE OF THE NEAR TERM PERIOD AS A
SHORTWAVE TROUGH LIFTS NORTHEASTWARD INTO SOUTHERN ONTARIO, WITH
THE RIDGE BECOMING CENTERED OFF THE SOUTHEASTERN ATLANTIC COAST BY
12Z FRIDAY. AS THIS OCCURS, A WEAK MID-LEVEL TROUGH (INITIALLY
ACROSS THE SOUTHERN FL PENINSULA) WILL LIFT NORTHWARD AROUND THE
WESTERN RIM OF THE RIDGE, BECOMING CENTERED ALONG THE GA COAST BY
12Z FRIDAY, AS WELL. ALTHOUGH LIGHT NORTHEASTERLY STEERING FLOW
WILL REMAIN IN PLACE ACROSS THE TN VALLEY TODAY, THESE CURRENTS
ARE PREDICTED TO COLLAPSE OVERNIGHT AS THE HEIGHT GRADIENT ALOFT
RELAXES.
AT THE SURFACE, OUR FORECAST AREA REMAINS ALONG THE WESTERN EDGE
OF AN ATLANTIC RIDGE CENTERED SOUTH OF BERMUDA, RESULTING IN
LIGHT/VARIABLE ENVIRONMENTAL FLOW. IN THE ABSENCE OF SYNOPTIC
SCALE FORCING FOR ASCENT, CONVECTION TODAY WILL LARGELY BE TIED TO
MESOSCALE OUTFLOW/DIFFERENTIAL HEATING BOUNDARIES RELATED TO
CONVECTION IN ADJACENT PORTIONS OF THE SOUTHEASTERN CONUS. IN
SIMILAR FASHION TO WHAT OCCURRED YESTERDAY, THUNDERSTORMS HAVE
ALREADY BEGUN TO DEVELOP LATE THIS MORNING IN THE HIGHER TERRAIN
OF THE SOUTHERN APPALACHIANS, WITH ADDITIONAL CONVECTIVE
DEVELOPMENT EXPECTED BY EARLY AFTERNOON ACROSS CENTRAL/SOUTHERN
PORTIONS OF MS/AL/GA. ALTHOUGH LINGERING DEBRIS CLOUDS AND A
CONVECTIVELY-OVERTURNED AIRMASS (BOTH STEMMING FROM WIDESPREAD
NOCTURNAL CONVECTION LAST NIGHT) WILL LIKELY DELAY CONVECTIVE
INITIATION IN OUR REGION UNTIL LATE THIS AFTERNOON (WHEN TEMPS
SHOULD FINALLY RECOVER INTO THE L-M 90S), GRADUAL COOLING AT THE
500-MB LEVEL AND DEWPOINTS IN THE U60S-M70S WILL SUPPORT MLCAPE OF
2500-3500 J/KG (IF NOT A BIT HIGHER). THIS ALONG WITH STEEP LAPSE
RATES IN THE SUBCLOUD LAYER AND DCAPE VALUES OF 1000-1250 J/KG
RANGE WILL SUPPORT A RISK FOR LOCALLY DAMAGING DOWNBURST WINDS (UP
TO 65 MPH), LARGE HAIL AND FREQUENT LIGHTNING. ADDITIONALLY,
STORMS WILL BE EFFICIENT RAINFALL PRODUCERS, AND WITH PWAT VALUES
SOLIDLY IN THE 1.7-1.8" RANGE, FLASH FLOODING MAY ALSO OCCUR IN A
FEW LOCATIONS.
THERE ARE INDICATIONS THAT AFTERNOON THUNDERSTORMS TO OUR
SOUTH/EAST MAY EVENTUALLY EVOLVE INTO A SMALL CLUSTER EARLY THIS
EVENING AS OUTFLOWS MERGE AND CONSOLIDATE, WITH SOME CONCERN THAT
A SIMILAR SCENARIO (COMPARED TO THIS MORNING) MAY UNFOLD ACROSS
OUR CWFA ONCE AGAIN THIS EVENING. OTHERWISE, ABUNDANT MID/HIGH-
LEVEL CLOUDS WILL SUPPORT WARM/MUGGY CONDITIONS OVERNIGHT, WITH
LOWS IN THE U60-L70S.
SHORT TERM
(FRIDAY THROUGH SATURDAY NIGHT)
ISSUED AT 1138 AM CDT THU JUN 26 2025
LATEST SHORT TERM MODEL CONSENSUS SUGGESTS THAT THE REMNANTS OF A
WEAK MID-LEVEL SHORTWAVE TROUGH WILL LIFT SLOWLY NORTH-
NORTHWESTWARD ACROSS GA THROUGH SATURDAY NIGHT, AROUND THE WESTERN
EDGE OF A SUBTROPICAL RIDGE OFF THE SOUTHEASTERN ATLANTIC COAST.
HOWEVER, THE MOST SIGNIFICANT IMPACT THAT THIS FEATURE WILL HAVE
ON OUR REGION WILL BE WEAK STORM STEERING CURRENTS, WHICH SHOULD
RESULT IN SLOW/ERRATIC CELL MOTIONS AND PERHAPS A GREATER RISK FOR
FLASH FLOODING. OTHERWISE, WE EXPECT CONVECTION ON FRIDAY TO BE
MOST PREVALENT ACROSS THE HIGHER TERRAIN TO OUR NORTHEAST AND IN
THE MORE UNSTABLE ENVIRONMENT ACROSS SOUTHERN PORTIONS OF THE GULF
COAST STATES, WITH DEVELOPMENT OF THUNDERSTORMS ACROSS OUR
FORECAST AREA LARGELY CONFINED TO THE AFTERNOON HOURS AND IN THE
VICINITY OF MESOSCALE OUTFLOW/DIFFERENTIAL HEATING BOUNDARIES. WE
WILL NEED TO KEEP AN EYE TO OUR EAST ONCE AGAIN FRIDAY NIGHT, AS A
SMALL CLUSTER OF STORMS ORIGINATING ACROSS THE SAVANNAH RIVER
VALLEY OF EASTERN GA/WESTERN SC MAY TEND TO SPREAD WESTWARD ACROSS
NORTHERN GA AND INTO THE TN VALLEY BY EARLY SATURDAY MORNING, BUT
THE LEVEL OF UNCERTAINTY IN THIS SCENARIO IS RATHER HIGH AT THIS
POINT (ESPECIALLY GIVEN THE WEAK NATURE OF STEERING CURRENTS
ALOFT).
A SIMILAR CONVECTIVE PATTERN WILL MATERIALIZE ON SATURDAY,
ALTHOUGH AS 500-MB HEIGHTS BEGIN TO RISE ALONG THE NORTHWEST GULF
COAST, A LIGHT NW FLOW ALOFT SHOULD BEGIN TO STEER CONVECTION
SOUTHEASTWARD ONCE AGAIN (IN A FASHION WE ARE MORE ACCUSTOMED TO),
AND THIS MAY ALLOW STORMS TO CONTINUE INTO THE EVENING/OVERNIGHT
HOURS, AS WELL. ALTHOUGH MLCAPE VALUES WILL RISE INTO THE
2500-3500 J/KG RANGE ON A DAILY BASIS, DCAPE VALUES BOTH FRIDAY
AND SATURDAY AFTERNOON MAY BE A BIT LOWER (750-1000 J/KG) BUT
STILL SUFFICIENTLY STRONG TO SUPPORT LOCALLY DAMAGING DOWNBURST
WINDS. WITH AFTERNOON HIGH TEMPERATURES PREDICTED TO FALL BACK
INTO THE U80S-L90S, WE HAVE NO PLANS AT THIS POINT TO EXTEND THE
HEAT ADVISORY BEYOND ITS CURRENT EXPIRATION (0Z SATURDAY), BUT
AFTERNOON HEAT INDEX READINGS WILL REMAIN IN THE 95-100F RANGE
THROUGHOUT THE SHORT TERM PERIOD.
LONG TERM
(SUNDAY THROUGH WEDNESDAY)
ISSUED AT 1158 PM CDT WED JUN 25 2025
THE WEAK UPPER LOW WILL BE PUSHED TOWARDS THE EASTERN SEABOARD
EARLY NEXT WEEK AS A LOW PRESSURE SYSTEM SLIDES OVER THE GREAT
LAKES AND ITS ASSOCIATED COLD FRONT APPROACHES THE TENNESSEE
VALLEY. WITH THIS PATTERN, EXPECT DAILY CHANCES OF SHOWERS AND
STORMS (30-60% CHANCE), ESPECIALLY DURING PEAK HEATING IN THE
AFTERNOON/EARLY EVENING. BY TUESDAY, RAIN AND STORM CHANCES ARE
FORECAST TO INCREASE (40-70%) AS THE AFOREMENTIONED SURFACE FRONT
APPROACHES THE REGION.
MODEL PWATS RANGE BETWEEN 1.7-1.9 INCHES FROM SATURDAY THROUGH
MONDAY AND, WHEN COMPARED WITH BMX SOUNDING CLIMATOLOGY, FALL
WITHIN THE 75-90TH PERCENTILES. PWATS INCREASE TO OVER 2 INCHES BY
MIDWEEK, WHICH WOULD BE GREATER THAN THE 90TH PERCENTILE. THUS,
SHOWERS WILL BE EFFICIENT RAINFALL PRODUCERS AND COULD OUTPERFORM
CURRENT FORECAST RAINFALL TOTALS FOR THE LONG TERM. AT LEAST
NUISANCE FLOODING WILL THEREFORE BE POSSIBLE THIS WEEKEND THROUGH
EARLY NEXT WEEK. AS FOR ANY CHANCE OF SEVERE STORMS, INSTABILITY
WILL BE SUFFICIENT BUT BULK SHEAR VALUES ARE LOW. SO, CONFIDENCE
IS LOW IN SEVERE STORM OCCURRENCE.
THE GOOD NEWS IS THAT WITH THE RETURN OF SHOWER/STORM CHANCES
WILL COME COOLER DAYTIME TEMPERATURES. HIGHS IN THE 85 TO 90
DEGREE RANGE ARE ANTICIPATED FROM TUESDAY AND WEDNESDAY DUE TO THE
HIGHER RAIN CHANCES. LOWS, HOWEVER, WILL REMAIN IN THE UPPER 60S
TO LOWER 70S EACH NIGHT.
AVIATION
(12Z TAFS)
ISSUED AT 627 AM CDT THU JUN 26 2025
VFR TO MVFR CONDITIONS ARE PREVAILING THIS MORNING AS A LINE OF
THUNDERSTORMS CONTINUES TO LIFT NORTH AND WEST OF THE AREA. EXPECT
THIS ACTIVITY TO BE MOSTLY OUT OF HERE BY 13Z, WITH VFR
CONDITIONS PREVAILING FROM THERE. SCATTERED THUNDERSTORMS WILL BE
POSSIBLE ONCE AGAIN THIS AFTERNOON, WITH HIGHER CONFIDENT IN
OCCURRENCE NEAR KHSV WHERE A PROB30 GROUP FOR RAIN WAS GIVEN
BETWEEN 22-00Z. AMENDMENTS MAY BE NEEDED AS THESE THUNDERSTORM
COMPLEXES EVOLVE.
HUN WATCHES/WARNINGS/ADVISORIES
AL...HEAT ADVISORY UNTIL 7 PM CDT FRIDAY FOR ALZ001>010-016.
TN...HEAT ADVISORY UNTIL 7 PM CDT FRIDAY FOR TNZ076-096-097.
NEAR TERM...70/DD
SHORT TERM...70/DD
LONG TERM...KTW
AVIATION...25
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