299
FXUS64 KHUN 060220
AFDHUN
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HUNTSVILLE AL
920 PM CDT SUN OCT 5 2025
..NEW NEAR TERM, SHORT TERM, LONG TERM
NEAR TERM
(THIS EVENING THROUGH MONDAY)
ISSUED AT 920 PM CDT SUN OCT 5 2025
SOUTH-SOUTHEASTERLY FLOW OF 15-25 KNOTS IN THE MID-LEVELS WILL
PERSIST ACROSS THE TN VALLEY OVERNIGHT, AS OUR REGION REMAINS
LOCATED BETWEEN A 500-MB RIDGE CENTERED OFF THE COAST OF NC AND AN
AMPLIFYING SHORTWAVE TROUGH OVER THE CENTRAL ROCKIES. HOWEVER,
WINDS ALOFT WILL VEER TO THE SOUTHWEST DURING THE DAY TOMORROW, AS
THE RIDGE TO OUR EAST BEGINS TO EXPAND SOUTHWESTWARD INTO THE
NORTHERN GULF. IN THE LOW-LEVELS, MODERATELY STRONG (AND
OCCASIONALLY GUSTY) ESE WINDS WILL CONTINUE FOR MUCH OF THE NEAR
TERM PERIOD DUE TO A CONTRACTED PRESSURE GRADIENT BETWEEN A HIGH
POSITIONED OFF THE NORTHERN MID-ATLANTIC COAST AND A SURFACE
TROUGH OVER THE NORTHWESTERN GULF (RELATED TO A WEAK MID-LEVEL
WAVE NEAR THE NORTHWEST GULF COAST) THAT WILL ADVANCE INLAND ALONG
THE TX COAST BY TOMORROW AFTERNOON.
PRESENT INDICATIONS ARE THAT SYNOPTIC SCALE ASCENT (DUE TO LOWER-
TROPOSPHERIC WARM ADVECTION) WILL INCREASE OVERNIGHT, AS A LOW-
LEVEL JET VEERS TO SSE AND STRENGTHENS TO 25-35 KNOTS ATOP
EASTERLY FLOW AT THE SURFACE. IN THE PRESENCE OF ABUNDANT DEEP-
LAYER MOISTURE (HIGHLIGHTED BY PWAT VALUES RISING INTO THE 1.8-2"
RANGE), THIS WILL SUPPORT A NORTHWESTWARD EXPANSION OF LOW STRATUS
CLOUDS AND DRIZZLE/LIGHT RAIN INTO OUR REGION THROUGHOUT THE
NIGHT. GIVEN THE GENTLE NATURE OF LIFT AND CAPE LESS THAN 250
J/KG, THE RISK FOR LIGHTNING/THUNDER APPEARS VERY LOW AND RAINFALL
AMOUNTS SHOULD BE LIGHT, AS WELL. DUE TO THE COMBINATION OF LOW
CLOUDS, DEWPOINTS IN THE L-M 60S AND ELEVATED WINDS IN THE
BOUNDARY LAYER, LOWS WILL BE RATHER MILD AND IN THE 65-70F RANGE
FOR MOST OF THE REGION.
FORECAST DATA FROM THE MOST RECENT SUITE OF CAMS AND GLOBAL
MODELS SUGGEST THAT LIGHT RAIN AND DRIZZLE WILL CONTINUE FOR A FEW
HOURS BEYOND 12Z, BUT SHOULD GRADUALLY BECOME MORE CONCENTRATED
TO THE NORTHWEST OF OUR CWFA LATE TOMORROW MORNING, AS THE
REMNANTS OF THE 500-MB WAVE (ALONG THE NORTHWEST GULF COAST) LIFT
NORTHEASTWARD AROUND THE EXPANDING SUBTROPICAL RIDGE TO OUR EAST.
HOWEVER, THE LOCAL AIRMASS WILL REMAIN VERY MOIST, AND A FEW
SHOWERS COULD OCCUR AT ANY POINT DURING THE AFTERNOON. WITH LOW
STRATUS CLOUDS EXPECTED TO PERSIST FOR MUCH OF THE MORNING AND
INTO THE FIRST PART OF TOMORROW AFTERNOON, HIGHS SHOULD ONLY REACH
THE U70S-L80S (AND THIS MAY EVEN BE A FEW DEGREES TOO WARM).
SHORT TERM
(MONDAY NIGHT THROUGH WEDNESDAY NIGHT)
ISSUED AT 920 PM CDT SUN OCT 5 2025
WEST-SOUTHWESTERLY FLOW ALOFT OF 15-25 KNOTS (TO THE NORTH OF A
FLAT SUBTROPICAL RIDGE LYING ACROSS THE GULF) WILL SUSTAIN A VERY
MOIST AIRMASS ACROSS THE TN VALLEY FROM MONDAY NIGHT-TUESDAY
NIGHT. HOWEVER, THE GREATEST CONCENTRATION OF SHOWERS AND
THUNDERSTORMS ON MONDAY NIGHT APPEARS AS IF IT WILL REMAIN
DISPLACED WELL TO OUR NORTHWEST (WHERE AN APPROACHING COLD FRONT
WILL INTERACT WITH A PREEXISTING SURFACE TROUGH). NEVERTHELESS, WE
WILL RETAIN A LOW CHANCE POP FOR SHOWERS AND A FEW THUNDERSTORMS
REGION-WIDE GIVEN THE PRESENCE OF ABUNDANT MOISTURE, A GRADUAL
INCREASE IN CAPE AND WEAK LIFT.
THE COVERAGE OF SHOWERS AND THUNDERSTORMS WILL BEGIN TO INCREASE
FOR THE NORTHWESTERN PORTION OF THE FORECAST AREA ON TUESDAY
AFTERNOON AS A PREFRONTAL WIND SHIFT AXIS DRIFTS SOUTHEASTWARD
INTO WESTERN PORTIONS OF KY/TN, AND WILL BE FAIRLY HIGH REGION-
WIDE FROM TUESDAY NIGHT-EARLY WEDNESDAY MORNING AS THE BOUNDARY
MAKES ITS WAY SLOWLY SOUTHEASTWARD ACROSS THE LOCAL FORECAST AREA.
ALTHOUGH CAPE WILL INCREASE AS DEWPOINTS RISE INTO THE M-U 60S,
VALUES SHOULD PEAK IN THE 1000-1500 J/KG RANGE TUESDAY AFTERNOON,
AND THIS COUPLED WITH DEEP-LAYER SHEAR BELOW THRESHOLDS FOR EVEN
MARGINAL STORM ORGANIZATION WILL REDUCE THE RISK FOR STRONG
STORMS. THAT SAID, LOCALLY HEAVY RAINFALL AND FLASH FLOODING MAY
BECOME A CONCERN IF PORTIONS OF THE AREA RECEIVE MULTIPLE ROUNDS
OF HEAVY RAINFALL.
STRENGTHENING NORTH-NORTHEASTERLY WINDS WILL GRADUALLY ADVECT A
SLIGHTLY COOLER/DRIER AIRMASS INTO THE REGION WEDNESDAY AND
WEDNESDAY NIGHT, AS A HIGH BUILDS EASTWARD FROM THE NORTHERN
PLAINS INTO SOUTHERN ONTARIO/QUEBEC. HOWEVER, DEPENDING ON THE
SPEED OF THE PREFRONTAL WIND SHIFT AXIS, SHOWERS AND THUNDERSTORMS
MAY CONTINUE FOR THE SOUTHEASTERN PORTION OF THE FORECAST AREA
THROUGH LATE WEDNESDAY MORNING. AFTER A TEMPORARY PERIOD OF DRY
CONDITIONS, ADDITIONAL CLOUDS AND LIGHT SHOWERS MAY EVOLVE ACROSS
THE EASTERN PORTION OF THE CWFA EARLY THURSDAY MORNING, AS A
DISTURBANCE APPROACHES IN WNW FLOW ALOFT AND INTERACTS WITH A
SUBTLE CONFLUENCE AXIS INDUCED BY COLD AIR DAMMING TO OUR EAST.
HIGHS WILL DROP BACK INTO THE U70S-L80S ON WEDNESDAY, WITH LOWS
THURSDAY MORNING IN THE 55-60F RANGE.
LONG TERM
(THURSDAY THROUGH SUNDAY)
ISSUED AT 920 PM CDT SUN OCT 5 2025
CONSENSUS GUIDANCE FROM THE LATEST SUITE OF GLOBAL MODELS
SUGGESTS THAT AN INITIALLY WEAK MID-LEVEL SHORTWAVE DISTURBANCE IN
WNW FLOW ALOFT WILL GRADUALLY DEVELOP INTO A STRONGER TROUGH
ACROSS THE SOUTHEASTERN CONUS OVER THE COURSE OF THE LONG TERM
PERIOD. ALTHOUGH WE WILL LIKELY REMAIN ON THE DRY SIDE OF THE
TROUGH, LOW-LEVEL MOISTURE AND CONVERGENCE WILL BOTH BE SUFFICIENT
FOR A CONTINUATION OF CLOUDS AND A FEW LIGHT SHOWERS ON THURSDAY
AND PERHAPS FRIDAY, AS WELL. HOWEVER, INCREASING DEEP- LAYER
NORTHERLY FLOW (TO THE WEST OF THE MID-LEVEL TROUGH AND A
DEVELOPING AREA OF SURFACE LOW PRESSURE OFF THE SOUTHEASTERN
ATLANTIC COAST) WILL EVENTUALLY ADVECT A DRIER AIRMASS INTO THE
REGION SATURDAY/SUNDAY, WITH ONLY A FEW SHOWERS POSSIBLE IN THE
HIGHER TERRAIN TO OUR NORTHEAST. THROUGH THE PERIOD, HIGHS WILL BE
IN THE M-U 70S, WITH LOWS IN THE 50S.
AVIATION
(00Z TAFS)
ISSUED AT 658 PM CDT SUN OCT 5 2025
CONDITIONS AT THE HSV/MSL AIRPORTS REMAIN VFR AT THE CURRENT
TIME, WITH A BROKEN LAYER OF STRATOCU BTWN 3500-5000 FT BENEATH A
SIMILAR COVERAGE OF CS. ALTHOUGH THE LOWER-BASED CLOUD DECK MAY
TEMPORARILY DISSIPATE EARLY IN THE TAF PERIOD, DEVELOPING LOW-
LEVEL WARM ADVECTION (RELATED TO A SSE LOW-LEVEL JET STRENGTHENING
TO 25-35 KNOTS) WILL SUPPORT NORTHWESTWARD EXPANSION OF LIGHT-
MODERATE RAIN INTO NORTHERN AL LATER THIS EVENING, WITH PROB30
GROUPS FOR RA AND TEMPORARY MVFR VSBY REDUCTIONS INCLUDED AT BOTH
TERMINALS BTWN 9-15Z. A LAYER OF LOW/MVFR STRATUS WILL ALSO
ACCOMPANY THE PRECIPITATION, AND SHOULD PERSIST INTO THE EARLY
AFTERNOON EVEN AS THE GREATEST CONCENTRATION OF RAIN BECOMES
DISPLACED WELL TO OUR NORTHWEST. ALTHOUGH A FEW SPOTTY SHOWERS
WILL REMAIN POSSIBLE THROUGH THE END OF THE TAF PERIOD, OVERALL
COVERAGE WILL DIMINISH AND WE WILL INDICATE AN IMPROVEMENT IN CIGS
BEYOND 20Z. SFC WINDS WILL REMAIN FROM ESE WITH SUSTAINED SPEEDS
OF 5-10 KNOTS AND GUSTS UP TO 15 KNOTS, AND LLWS HAS BEEN RETAINED
FOR THE OVERNIGHT PERIOD.
HUN WATCHES/WARNINGS/ADVISORIES
AL...NONE.
TN...NONE.
NEAR TERM...70/DD
SHORT TERM...70/DD
LONG TERM...70/DD
AVIATION...70/DD
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