645
FXUS64 KHUN 021158
AFDHUN
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HUNTSVILLE AL
658 AM CDT FRI OCT 2 2026
..NEW AVIATION
KEY MESSAGES
UPDATED AT 1127 PM CDT THU OCT 1 2026
- CHANCES FOR SHOWERS AND THUNDERSTORMS WILL INCREASE FROM 20-50%
TODAY AND TONIGHT TO 40-60% BY SATURDAY AFTERNOON. LIGHTNING
AND BRIEF HEAVY RAINFALL WILL BE THE MAIN IMPACTS FROM THE
STORMS.
- A FAIRLY WIDESPREAD COVERAGE OF RAIN (AND SOME EMBEDDED
THUNDERSTORMS) IS EXPECTED FROM EARLY SUNDAY MORNING THROUGH
MUCH OF THE DAY. THE RISK FOR FLASH AND AREAL FLOODING WILL BE
GREATEST DURING THIS PERIOD.
- A COLD FRONT WILL USHER A DRIER AIRMASS INTO THE REGION EARLY
MONDAY MORNING, WHICH WILL REMAIN IN PLACE FOR THE REST OF THE
WEEK.
NEAR TERM
(TODAY)
ISSUED AT 353 AM CDT FRI OCT 2 2026
NOT MUCH CHANGE TO THE NEAR TERM FORECAST AS CURRENT OBS SHOW
CALM WINDS ACROSS THE TN VALLEY AS LOW/MID LEVEL STRATUS VERY
SLOWLY EXPANDS EAST OVER AR AND MS. CURRENT TEMPS RANGE FROM THE
MID 60S TO LOWER 70S MAKING IT A WARM NIGHT COMPARED TO RECENT
OVERNIGHT PERIODS. EXPECT TO SEE A CONTINUED EASTWARD EXPANSION OF
THE MID TO LOW LEVEL STRATUS DECK WITH LOW TO MEDIUM (20-50%)
CHANCE POPS ENTERING THE FORECAST AROUND AND AFTER NOON. THE
GREATEST CHANCES FOR RAIN AND STORMS TODAY WILL BE OVER NW AL.
ABNORMALLY HOT TEMPERATURES WILL LEAD TO MINOR TO MODERATE
HEATRISK LEVELS ACROSS THE TN VALLEY THIS AFTERNOON WITH HIGHS IN
THE LOWER 90S AND HEAT INDICES IN THE MID 90S NEARING 100 DEGREES
IN URBAN LOCATIONS.
PREVIOUS DISCUSSION:
IN THE MID/UPPER-LEVELS, S-SW FLOW ALOFT OF 15-25 KNOTS WILL
GRADUALLY BACK TO W-SW OVER THE COURSE OF THE NEAR TERM PERIOD AS
OUR REGION WILL REMAIN SITUATED BETWEEN A HIGH CENTERED OFF THE
SOUTHEASTERN ATLANTIC COAST AND AN AMPLIFYING NORTHERN STREAM WAVE
MOVING EASTWARD ACROSS SOUTHERN OT/QC. AT THE SURFACE, LIGHT-
MODERATE S-SE FLOW WILL CONTINUE OVERNIGHT, AS A RIDGE OF HIGH
PRESSURE SHIFTS EASTWARD OFF THE COAST OF NC. ALTHOUGH THIS WILL
NOT HAVE A SIGNIFICANT IMPACT ON BOUNDARY LAYER DEWPOINTS, A
MODEST LOW-LEVEL JET WILL CONTRIBUTE TO AN INCREASE IN LOW STRATUS
CLOUDS PRIOR TO SUNRISE, WHICH (ALONG WITH SLIGHTLY ELEVATED
WINDS) SHOULD KEEP OVERNIGHT LOWS IN THE 65-70F RANGE. WELL TO THE
NORTHWEST OF OUR REGION, A COLD FRONT EXTENDS FROM CENTRAL QC
SOUTHWESTWARD THROUGH LOWER MI, CENTRAL IL/MO AND TO A DECAYING
AREA OF LOW PRESSURE ACROSS NORTHWEST TX. AS SURFACE PRESSURES
GRADUALLY RISE WITHIN AN ANTICYCLONE ACROSS THE NORTHERN PLAINS,
THE FRONT WILL CONTINUE TO DRIFT SOUTHEASTWARD OVERNIGHT, BUT WITH
MOST OF THE RELATED PRECIPITATION EXPECTED TO BE ANAFRONTAL IN
NATURE, CONDITIONS ACROSS OUR CWFA WILL REMAIN DRY THROUGH 12Z.
THE COLD FRONT WILL CONTINUE TO ADVANCE SLOWLY SOUTHEASTWARD
TOMORROW AS THE CENTER OF A CANADIAN SURFACE HIGH MIGRATES FURTHER
EASTWARD INTO THE UPPER MS VALLEY. ALTHOUGH IT APPEARS AS IF THE
LEADING EDGE OF THE COOLER/DRIER CONTINENTAL AIRMASS WILL
EVENTUALLY STALL ALONG AN AXIS FROM NORTHERN AR EAST-NORTHEASTWARD
INTO THE CENTRAL APPALACHIANS, A PREFRONTAL SURFACE TROUGH/WIND
SHIFT AXIS WELL AHEAD OF THE THERMAL/MOISTURE GRADIENT MAY
INITIATE DEVELOPMENT OF A FEW SHOWERS AND THUNDERSTORMS TOMORROW
AFTERNOON (PARTICULARLY ACROSS NORTHWEST AL AND SOUTHERN MIDDLE
TN, WHERE CURRENT POPS ARE IN THE 30-40% RANGE). HOWEVER,
ADDITIONAL CONVECTION MAY ALSO EVOLVE IN THE HIGHER TERRAIN OF
NORTHEAST AL. INSTABILITY MAY INITIALLY BE LIMITED BY MORNING
STRATUS, BUT AS CLOUDS BASES LIFT DURING THE AFTERNOON,
TEMPERATURES WARMING INTO THE U80S-L90S WILL SUPPORT CAPE IN THE
500-1000 J/KG RANGE WITHIN AN ENVIRONMENT OF WEAK SHEAR. THUS,
LIGHTING WILL BE THE PRIMARY CONCERN WITH THUNDERSTORM ACTIVITY
TOMORROW.
SHORT TERM
(FRIDAY NIGHT THROUGH SUNDAY NIGHT)
ISSUED AT 1127 PM CDT THU OCT 1 2026
LATEST SHORT RANGE MODEL GUIDANCE SUGGESTS THAT A SUBTROPICAL
RIDGE WILL GRADUALLY RETROGRADE FROM THE SOUTHWESTERN NORTH
ATLANTIC INTO THE SOUTHERN GULF OVER THE COURSE OF THE SHORT TERM
PERIOD. THIS EVOLUTION WILL MAINTAIN WEAKLY CONFLUENT FLOW ALOFT
ACROSS OUR REGION (BETWEEN THE HIGH TO OUR SOUTHEAST AND A PAIR OF
NORTHERN STREAM TROUGHS TRAVELING ALONG THE U.S.-CANADIAN
BORDER). ALTHOUGH THIS TYPE OF PATTERN WOULD NORMALLY NOT BE
CONDUCIVE FOR EITHER WIDESPREAD OR INTENSE PRECIPITATION, A
SURFACE TROUGH/WIND-SHIFT AXIS WILL DRIFT FURTHER SOUTHEASTWARD
INTO THE REGION ON FRIDAY NIGHT (BEFORE BECOMING STATIONARY ON
SATURDAY), AND THIS FEATURE SHOULD PROVIDE SUFFICIENT LIFT WITHIN
THE INCREASINGLY MOIST AIRMASS (HIGHLIGHTED BY PWAT VALUES IN THE
1.8-2" RANGE, AND POTENTIALLY IN EXCESS OF 2") TO SUPPORT
DEVELOPMENT OF SHOWERS AND THUNDERSTORMS. THE SPATIAL COVERAGE OF
CONVECTIVE CELLS WILL BE NOTABLY HIGHER DURING THE AFTERNOON ON
SATURDAY (COMPARED TO FRIDAY NIGHT) AND TO THE SOUTH/EAST OF THE
STREAMLINE CONFLUENCE AXIS. HOWEVER, WITH A LARGE AMOUNT OF
UNCERTAINTY REGARDING PRECISELY WHERE THE BOUNDARY WILL LIE, POPS
RANGE FROM 40%/NW TO 60%/SE. WEAK SHEAR WILL CONTINUE TO SUPPORT
UNORGANIZED CONVECTIVE UPDRAFTS DURING THIS PERIOD, BUT AFTERNOON
TEMPS IN THE M-U 80S MAY SUPPORT SLIGHTLY HIGHER CAPE AS DEWPOINTS
RISE INTO THE U60S-L70S. REGARDLESS, LIGHTING AND LOCALLY HEAVY
RAINFALL WILL BE THE MAIN STORM IMPACTS.
DURING THE PERIOD FROM SATURDAY NIGHT-SUNDAY, THE LOW-LEVEL
CONVERGENCE AXIS MAY ATTEMPT TO LIFT NORTHWESTWARD IN RESPONSE TO
AN AMPLIFYING NORTHERN STREAM TROUGH THAT WILL TRAVEL EAST-
SOUTHEASTWARD INTO SOUTHERN OT AND THE WESTERN GREAT LAKES BY 12Z
SUNDAY. AS THIS OCCURS, FRONTOGENETICAL FORCING WILL GRADUALLY
STRENGTHEN IN THE LOWER TROPOSPHERE, AND THIS COUPLED WITH WEAK
LIFT ALONG THE SOUTHERN FLANK OF THE TROUGH TO OUR NORTH MAY
RESULT IN AN INCREASE IN BOTH THE COVERAGE AND INTENSITY OF RAIN
AND EMBEDDED THUNDERSTORMS BEGINNING EARLY SUNDAY MORNING AND
CONTINUING FOR MUCH OF THE DAY. ALTHOUGH WEAK SHEAR AND
INSTABILITY WILL CONTINUE TO LIMIT STORM INTENSITY, IT IS DURING
THIS TIMEFRAME THAT THE RISK FOR FLASH AND AREAL FLOODING WILL BE
GREATEST (ESPECIALLY AS PWAT VALUES MAY BE IN EXCESS OF 2").
CURRENT THINKING IS THAT RAIN AND THUNDERSTORMS WILL SLOWLY END
FROM NW-TO-SE LATE SUNDAY AFTERNOON AND SUNDAY EVENING AS A COLD
FRONT SHIFTS SOUTHWARD INTO THE FORECAST AREA, WITH STRENGTHENING
N-NE WINDS IN THE WAKE OF THE FRONT ADVECTING A DRIER AIRMASS INTO
THE NORTHERN PART OF THE REGION BY EARLY MONDAY MORNING. HIGH
TEMPERATURES ON SUNDAY WILL BE REDUCED TO THE 75-80F RANGE DUE TO
WIDESPREAD CLOUDS AND PRECIPITATION, WITH TEMPS BY MONDAY MORNING
FALLING INTO THE U50S-L60S.
LONG TERM
(MONDAY THROUGH THURSDAY)
ISSUED AT 1127 PM CDT THU OCT 1 2026
GLOBAL MODELS SUGGEST THAT A REINFORCING SURFACE HIGH WILL SHIFT
EASTWARD FROM THE UPPER MS VALLEY INTO THE MID-ATLANTIC REGION ON
MONDAY AND TUESDAY, WITH MODERATE N-NE FLOW VEERING TO THE SE AS
PRESSURES BEGIN TO RISE TO THE EAST OF THE CENTRAL/SOUTHERN
APPALACHIANS. ALTHOUGH A TEMPORARY INCREASE IN CLOUDS (AND PERHAPS
A FEW LIGHT SHOWERS) MAY OCCUR AT THE ONSET OF THIS REGIME ON
TUESDAY, A DRIER AIRMASS WILL LIKELY RETURN FROM THE EAST FOR THE
LAST COUPLE OF DAYS OF THE FORECAST PERIOD. AFTERNOON HIGHS WILL
REMAIN IN THE U70S-M80S, WITH OVERNIGHT LOWS IN THE M40S-L50S.
AVIATION
(12Z TAFS)
ISSUED AT 658 AM CDT FRI OCT 2 2026
VFR CONDITIONS HAVE LINGERED LONGER THAN ORIGINALLY FORECAST THIS
MORNING AS LOW TO MID STRATUS EXPANDS BOTH TO OUR WEST AND EAST.
IT REMAINS LOW CONFIDENCE WHEN OR IF THESE CONDITIONS WILL MAKE IT
TO OUR AREA THIS MORNING, BUT LOWER CIGS ARE FORECAST AT LEAST BY
THE OVERNIGHT HOURS TONIGHT. LOW CHANCES FOR RAIN AND THUNDER WILL
EXIST OVER NW AL TODAY, SO INCLUDED A PROB30 GROUP AT MSL TO COVER
THIS RISK. CONFIDENCE IN THUNDERSTORM COVERAGE CLOSER TO THE HSV
TERMINAL IS MUCH LOWER, SO WE HAVE LEFT ANY MENTION OF RAIN OUT OF
THE TAF FOR NOW. AMENDMENTS MAY BE NEEDED IF CLOUD COVER TRENDS
SPEED UP THIS MORNING.
HUN WATCHES/WARNINGS/ADVISORIES
AL...NONE.
TN...NONE.
NEAR TERM...25
SHORT TERM....70
LONG TERM....70
AVIATION...25
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