498
FXUS64 KHUN 130830
AFDHUN
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HUNTSVILLE AL
330 AM CDT MON OCT 13 2025
..NEW NEAR TERM
NEAR TERM
(TODAY)
ISSUED AT 330 AM CDT MON OCT 13 2025
SURFACE HIGH PRESSURE FROM EASTERN CANADA TO THE DEEP SOUTH WAS
CONTROLLING THE GENERAL WEATHER SITUATION ACROSS THE GREATER
TENNESSEE VALLEY. WITH LONGER AUTUMN NIGHTS, 3 AM TEMPERATURES
HAVE COOLED INTO THE UPPER 40S TO LOWER 50S WITH LIGHT WINDS.
UNDER CLEAR SKIES, STRONG RADIATIVE COOLING CREATES A FAVORABLE
ENVIRONMENT FOR THE DEVELOPMENT OF LATE NIGHT FOG. AT THE PRESENT,
SURFACE VISIBILITIES WERE LOCALLY REDUCED AT ALBERTVILLE,
GUNTERSVILLE, WINCHESTER, CORINTH AND PULASKI. WITH ~3 1/2 HOURS
BEFORE DAYBREAK, THERE IS AN OPPORTUNITY FOR MORE FOG TO FORM.
THAT SAID (AND FORTUNATELY) MOST OF MOS GUIDANCE AND THE NBM WERE
NOT GOING WITH MORE FOG AT THIS TIME. IT'S SOMETHING WE'LL MONITOR.
UPPER LEVEL RIDGING OVER COASTAL TEXAS WILL BUILD TO THE NE OVER
THE NEXT COUPLE OF DAYS. IT WILL HELP WEAKEN AND PUSH TROUGHING
THAT HAS BEEN HANGING TOUGH ALONG THE EASTERN SEABOARD MORE OFF
SHORE DURING TUE/WED. WITH HIGH PRESSURE ALOFT AND AT THE SURFACE,
DRY CONDITIONS WITH CONTINUE THROUGH THE MID WEEK. HIGH TEMPS
LATER TODAY SHOULD RISE INTO THE MID/UPPER 70S TO LOWER 80S WITH
LIGHT NORTHERLY WINDS. NORMAL HIGHS IN HUNTSVILLE AND MUSCLE
SHOALS ARE AROUND 77 DEGREES.
SHORT TERM
(MONDAY NIGHT THROUGH WEDNESDAY NIGHT)
ISSUED AT 1039 PM CDT SUN OCT 12 2025
LATEST SHORT RANGE FORECAST DATA SUGGESTS THAT LIGHT-MODERATE NNW
FLOW ALOFT WILL PERSIST ACROSS THE TN VALLEY THROUGHOUT THE SHORT
TERM PERIOD. THIS WILL OCCUR AS A SUBTROPICAL HIGH (INITIALLY
STRENGTHENING ACROSS EAST TX MONDAY NIGHT/TUESDAY) BEGINS TO
WEAKEN OVER THE RED RIVER VALLEY TUESDAY NIGHT/WEDNESDAY BEFORE
TRANSLATING SOUTHEASTWARD INTO THE CENTRAL GULF COAST BY WEDNESDAY
NIGHT. IN THE LOW-LEVELS, LIGHT-MODERATE NORTHEAST FLOW WILL
CONTINUE AS AN UPSTREAM SURFACE HIGH (INITIALLY ALONG THE
U.S-CANADIAN INTERNATIONAL BORDER) SPREADS EAST-SOUTHEASTWARD INTO
SOUTHERN ONTARIO AND THE NORTHERN GREAT LAKES, WEAKENING WITH
TIME. DUE TO THE COMBINED INFLUENCES FROM THE RIDGE ALOFT AND
REINFORCEMENT OF DRY ADVECTION AT THE SURFACE, WE ANTICIPATE NO
PRECIPITATION THROUGH THE PERIOD. ALTHOUGH DETERMINISTIC MODEL
GUIDANCE SUGGESTS THAT HIGHS WILL REMAIN IN THE U70S-L80S FOR MUCH
OF THE REGION, CONDITIONS WILL BE FAVORABLE FOR A DEEP MIXING
LAYER EACH AFTERNOON AND FOR THIS REASON A FEW READINGS (PERHAPS
AS HIGH AS THE UPPER 80S) MAY OCCUR (ESPECIALLY IN THE WEST).
OVERNIGHT LOWS WILL BE IN THE L-M 50S.
LONG TERM
(THURSDAY THROUGH SUNDAY)
ISSUED AT 1039 PM CDT SUN OCT 12 2025
THE EXTENDED PORTION OF THE FORECAST PERIOD WILL BEGIN WITH AN
AMPLIFIED MID-LEVEL RIDGE EXTENDING NORTHWARD INTO THE GULF COAST
STATES FROM A WEAKENING SUBTROPICAL HIGH TO ITS SOUTH. ALTHOUGH
THE RIDGE AXIS WILL SHIFT EASTWARD ACROSS THE REGION ON THURSDAY
NIGHT (ALLOWING SOUTHWESTERLY FLOW ALOFT TO RETURN ON
FRIDAY/FRIDAY NIGHT), DRY CONDITIONS WILL CONTINUE AS ONSET OF
SOUTHERLY RETURN FLOW IN THE BOUNDARY LAYER WILL INITIALLY HAVE
LITTLE IMPACT ON DEWPOINTS.
HOWEVER, DURING THE PERIOD FROM SATURDAY-SUNDAY, CHANCES FOR RAIN
AND THUNDERSTORMS WILL INCREASE REGION-WIDE AS DEEP-LAYER
SOUTHWESTERLY FLOW STRENGTHENS AHEAD OF AN AMPLIFYING MID-LEVEL
TROUGH APPROACHING THE REGION FROM THE WEST, ALLOWING PWAT VALUES
TO QUICKLY RISE BACK INTO THE 1.5-1.7" RANGE. AT THIS POINT, THERE
REMAIN SUBSTANTIAL DIFFERENCES IN THE GLOBAL MODELS REGARDING
BOTH THE EVOLUTION AND SPEED OF THE MID-LEVEL TROUGH (AND RELATED
COLD FRONT), WHICH WILL HAVE LARGE IMPACTS ON BOTH TIMING/COVERAGE
OF PRECIPITATION AND THE POTENTIAL FOR ORGANIZED CONVECTION. FOR
EXAMPLE, THE ECMWF MODEL SUGGESTS A MORE AMPLIFIED DISTURBANCE IN
THE SOUTHERN PORTION OF THE TROUGH WHICH (FOR OUR FORECAST AREA)
WOULD RESULT IN STRONGER SOUTHWESTERLY FLOW ALOFT/BULK SHEAR BUT
WEAKER LAPSE RATES/CAPE. ON THE OTHER HAND, THE GFS MODEL
INDICATES THAT THE NORTHERN STREAM WILL REMAIN DOMINANT, WITH
WEAKER SHEAR ACCOMPANIED BY STEEPER LAPSE RATES AND HIGHER
INSTABILITY. REGARDLESS, THIS IS A SYSTEM THAT WE WILL NEED TO
MONITOR OVER THE COMING DAYS FOR PERHAPS A LOW THREAT OF STRONG-
SEVERE THUNDERSTORMS. AS A RESULT OF CLOUDS AND PRECIP, HIGHS WILL
FALL BACK INTO THE L-M 70S BY SUNDAY AS LOWS RISE INTO THE
U50S-L60S.
AVIATION
(06Z TAFS)
ISSUED AT 1236 AM CDT MON OCT 13 2025
THERE HAVE BEEN NO CHANGES TO PREVIOUS AVIATION FORECAST
REASONING, AS VFR CONDITIONS FEATURING CLEAR SKIES AND A LIGHT NNE
WIND WILL CONTINUE AT THE MSL/HSV TERMINALS EARLY THIS MORNING.
IF WINDS TEMPORARILY BECOME CALM, DEVELOPMENT OF PATCHY BR/FG WILL
BE POSSIBLE AT BOTH AIRPORTS BTWN 8-12Z, AND A TEMPO GROUP FOR
MVFR VSBY REDUCTIONS HAS BEEN INCLUDED DURING THIS TIMEFRAME. A
FEW FAIR-WEATHER CU WILL DEVELOP BY 15Z MONDAY (BENEATH AN
INCREASING COVERAGE OF CI), WITH NNE WINDS STRENGTHENING TO 5-10
KTS AROUND THIS TIME, AS WELL.
HUN WATCHES/WARNINGS/ADVISORIES
AL...NONE.
TN...NONE.
NEAR TERM...RSB
SHORT TERM....70/DD
LONG TERM....70/DD
AVIATION...70/DD
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