030
FXUS64 KHUN 080405
AFDHUN
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HUNTSVILLE AL
1105 PM CDT MON SEP 7 2026
..NEW NEAR TERM, SHORT TERM, LONG TERM
KEY MESSAGES
UPDATED AT 1105 PM CDT MON SEP 7 2026
- LOW CHANCES FOR SHOWERS AND THUNDERSTORMS WILL RETURN TO THE
NORTHERN PART OF THE FORECAST AREA THURSDAY AND THURSDAY NIGHT.
- AS A MOIST AIRMASS RETURNS TO THE REGION, CHANCES FOR SHOWERS
AND THUNDERSTORMS WILL INCREASE TO 40-60% ON FRIDAY/SATURDAY
AFTERNOONS, BEFORE FALLING INTO THE 20-40% RANGE SUNDAY/MONDAY.
LIGHTNING AND HEAVY RAINFALL WILL BE THE MAIN IMPACTS FROM THE
STORMS.
- NWS HEAT RISK WILL REMAIN IN THE MINOR TO MODERATE CATEGORY
THROUGHOUT THE FORECAST PERIOD.
NEAR TERM
(THIS EVENING THROUGH TUESDAY)
ISSUED AT 1105 PM CDT MON SEP 7 2026
IN THE MID/UPPER-LEVELS, WEAKENING NORTHEAST FLOW ALOFT WILL
GRADUALLY VEER TO THE ESE BY SUNRISE AS OUR REGION BEGINS TO
EXPERIENCE INCREASING INFLUENCE FROM A STRENGTHENING SUBTROPICAL
RIDGE ACROSS THE SOUTHERN GREAT PLAINS (WHICH WILL BECOME CENTERED
OVER THE TN VALLEY BY THE END OF THE PERIOD). IN THE LOW-LEVELS,
SURFACE HIGH PRESSURE (WHICH TRANSLATED SOUTHEASTWARD INTO THE
NORTHERN MID-ATLANTIC STATES EARLIER TODAY IN THE WAKE OF A
DEPARTING NORTHERN STREAM TROUGH) WILL STRENGTHEN OVERNIGHT, WITH
PRESSURE RISES EXPECTED IN THE LEE OF THE CENTRAL/SOUTHERN
APPALACHIANS. AS THIS OCCURS, SOUTHEASTERLY FLOW WILL CONTINUE TO
BECOME ESTABLISHED FROM E-TO-W THIS EVENING, AND ALTHOUGH THERE
REMAINS A VERY LOW CHANCE FOR DEVELOPMENT OF A SHOWER OR TWO IN
THE VICINITY OF THE NATURALLY-INDUCED STREAMLINE CONFLUENCE AXIS
AS IT PROGRESSES THROUGH NORTHWEST AL, PROBABILITIES FOR THIS TO
OCCUR ARE IN THE 10-20% RANGE. IN THE WAKE OF THIS FEATURE, A
BROKEN DECK OF LOWER-LEVEL STRATOCUMULUS CLOUDS WILL SPREAD WEST-
NORTHWESTWARD OVER THE TN VALLEY, WITH A FEW SPRINKLES OF RAIN (OR
PERHAPS A LIGHT SHOWER) POSSIBLE AS WELL, BUT CHANCES FOR
MEASURABLE RAINFALL AT ANY ONE LOCATION REMAIN 5-10%. AS THE SE
FLOW BEGINS TO ADVECT A DRIER CONTINENTAL AIRMASS INTO THE REGION,
DEWPOINTS WILL FALL INTO THE L-M 60S ACROSS THE EAST BY 12Z, WITH
OVERNIGHT LOWS RANGING FROM THE M60S IN THIS PORTION OF THE
FORECAST AREA TO THE L70S IN THE WEST.
THE LOW-LEVEL SE FLOW REGIME (DESCRIBED ABOVE) WILL STRENGTHEN AS
MIXING BEGINS AFTER SUNRISE, WITH GUSTS UP TO AROUND 20 MPH
EXPECTED FOR MUCH OF THE DAY. ALTHOUGH THE REGIME OF PARTLY-MOSTLY
CLOUDY SKIES AND A FEW SPRINKLES OF RAIN (OR LIGHT SHOWERS) WILL
CONTINUE FOR MUCH OF THE LATE MORNING PERIOD, CLOUDS WILL BEGIN TO
DISPERSE FROM E-TO-W DURING THE AFTERNOON HOURS. THIS WILL
PROVIDE SUFFICIENT TIME FOR AFTERNOON HIGHS TO REACH VALUES ONLY A
COUPLE OF DEGREES COOLER (COMPARED TO TODAY), WITH MOST VALLEY
LOCATIONS IN THE U80S-L90S.
SHORT TERM
(TUESDAY NIGHT THROUGH THURSDAY NIGHT)
ISSUED AT 1105 PM CDT MON SEP 7 2026
SHORT RANGE MODEL CONSENSUS SUGGESTS THAT THE TN VALLEY WILL
REMAIN UNDER THE INFLUENCE OF A STRONG 500-MB RIDGE DURING THE
PERIOD FROM TUESDAY NIGHT-WEDNESDAY NIGHT, AS ITS CENTER MIGRATES
SLOWLY EASTWARD INTO THE SOUTHEASTERN ATLANTIC COAST. AT THE
SURFACE, A WEAKENING DOME OF HIGH PRESSURE WILL SHIFT SLOWLY
EASTWARD OFF THE MID-ATLANTIC COAST, BUT SHOULD PROVIDE SUFFICIENT
INFLUENCE TO SUSTAIN LIGHT SSE WINDS AND A PLUME OF RELATIVELY
LOWER DEWPOINTS ACROSS OUR REGION. THIS WILL TRANSLATE TO A
CONTINUATION OF DRY WEATHER, WITH MORNING LOWS IN THE U60S-L70S
(PERHAPS A FEW DEGREES COOLER IN THE SHELTERED VALLEYS OF
NORTHEAST AL/SOUTHERN TN) AS AFTERNOON HIGHS RISE BACK INTO THE
L-M 90S (WITH LESS MORNING CLOUD COVER).
BY THURSDAY AND THURSDAY NIGHT, THE SUBTROPICAL RIDGE IS
PREDICTED TO WEAKEN AND SHIFT EASTWARD INTO THE SOUTHWESTERN NORTH
ATLANTIC, ALLOWING A LIGHT WSW FLOW TO DEVELOP ALOFT. AS THIS
OCCURS, LIGHT SW FLOW WILL BECOME ESTABLISHED IN THE LOW-LEVELS
AHEAD OF A COLD FRONT (ATTACHED TO AN OCCLUDING CYCLONE ACROSS
NORTHERN QUEBEC) THAT WILL INITIALLY EXTEND FROM EASTERN CO
NORTHEASTWARD INTO SOUTHEASTERN QUEBEC. ALTHOUGH THE FRONT WILL
EXHIBIT VERY LITTLE (IF ANY) MOVEMENT, A PREFRONTAL WIND SHIFT
AXIS WILL FOCUS THE DEVELOPMENT OF WIDESPREAD CONVECTION (WELL TO
OUR NORTH) ON WEDNESDAY NIGHT AND THURSDAY, WHICH SHOULD FORCE THE
PREFRONTAL WIND SHIFT AXIS TO DRIFT SOUTHEASTWARD WITH TIME. THIS
FEATURE WILL LIKELY INITIATE NEW CLUSTERS OF SHOWERS AND
THUNDERSTORMS AS IT SLOWLY APPROACHES OUR CWFA, BUT WITH A VERY
LOW PROBABILITY THAT IT WILL ACTUALLY ENTER OUR REGION, WE WILL
ONLY INCLUDE A 20-30% POP (GENERALLY FOCUSED ACROSS NORTHWEST
AL/SOUTHERN TN). DUE TO THE LINGERING PRESENCE OF A DRIER (BUT
GRADUALLY MODIFYING) CONTINENTAL AIRMASS ACROSS OUR REGION, CAPE
WILL BE ON THE LOW SIDE (BUT CERTAINLY ADEQUATE FOR DEVELOPMENT OF
SOME THUNDERSTORMS). THIS, COUPLED WITH WEAK VERTICAL WIND SHEAR,
SUGGEST THAT ANY STORMS WILL BE UNORGANIZED AND LIGHTNING SHOULD
BE THE PRIMARY IMPACT. HIGHS WILL REMAIN IN THE L-M 90S ON
THURSDAY, WITH OVERNIGHT LOWS ONCE AGAIN IN THE U60S-L70S.
LONG TERM
(FRIDAY THROUGH MONDAY)
ISSUED AT 1105 PM CDT MON SEP 7 2026
EXTENDED RANGE MODEL DATA SUGGESTS THAT A SUBTLE LOW-LEVEL
STREAMLINE CONFLUENCE AXIS (INITIALLY POSITIONED ACROSS THE TN
VALLEY) WILL LIFT NORTHWARD INTO THE OH VALLEY AND LOSE DEFINITION
DURING THE PERIOD FROM FRIDAY-SATURDAY NIGHT, IN RESPONSE TO
SURFACE PRESSURE FALLS ACROSS THE SOUTHERN HIGH PLAINS. THIS,
ALONG WITH SW FLOW ALOFT (PROVIDED BY A WEAK MID- LEVEL TROUGH
DRIFTING EASTWARD OVER THE LOWER MS VALLEY), WILL FORCE PWAT
VALUES BACK INTO THE 1.8-2" RANGE, LEADING TO A GENERAL INCREASE
IN THE COVERAGE OF SHOWERS AND THUNDERSTORMS BOTH DAYS. WITH NO
CLEAR EVIDENCE OF SYNOPTIC SCALE FORCING FOR ASCENT, SUBTLE DEEP-
LAYER WARM/MOIST ADVECTION AND MESOSCALE BOUNDARIES WILL LIKELY BE
THE SOURCE OF UNORGANIZED CONVECTION (LARGELY TIED TO THE DIURNAL
WARMING CYCLE, BUT WITH SOME POTENTIAL FOR CONVECTION TO PERSIST
AT NIGHT, AS WELL).
ON SUNDAY AND MONDAY, THERE ARE INDICATIONS THAT THE ATLANTIC
SUBTROPICAL RIDGE WILL BEGIN TO STRENGTHEN AS IT RETROGRADES
WESTWARD INTO THE SOUTHEASTERN CONUS. ALTHOUGH THIS COULD
POTENTIALLY HAVE A NEGATIVE INFLUENCE ON THE OVERALL COVERAGE OF
AFTERNOON CONVECTION, LOW-LEVEL MOISTURE RETURN WILL IMPROVE AS
SOUTHERLY FLOW BECOMES ESTABLISHED WITHIN THE WARM SECTOR OF A LOW
TRACKING NORTHEASTWARD INTO THE UPPER MS VALLEY. WITH DEWPOINTS
RETURNING TO THE L-M 70S, PWAT VALUES WILL CONTINUE TO RISE ABOVE
2" AND THIS COUPLED WITH COLLAPSING STEERING CURRENTS ALOFT MAY
ENHANCE THE RISK FOR LOCALLY HEAVY RAINFALL AND FLOODING DURING
THIS PERIOD. DUE TO INCREASED RAIN CHANCES, HIGHS WILL FALL BACK
INTO THE U80S-L90S, AS OVERNIGHT LOWS REMAIN IN THE U60S-L70S.
AVIATION
(00Z TAFS)
ISSUED AT 749 PM CDT MON SEP 7 2026
SOUTHEASTERLY LOW-LEVEL FLOW WILL CONTINUE TO BECOME ESTABLISHED
ACROSS THE REGION (FROM E-TO-W) THIS EVENING, AS SURFACE HIGH
PRESSURE DEVELOPS SOUTHWARD THROUGH THE SOUTHERN MID-ATLANTIC
STATES. ALTHOUGH A FEW EVENING SHOWERS MAY OCCUR INVOF A
CONVERGENCE BOUNDARY AT THE INTERFACE OF THE HIGH, THIS ACTIVITY
WOULD ONLY IMPACT THE WESTERN PORTION OF THE FORECAST AREA AND
SHOULD REMAIN SUFFICIENTLY ISOLATED IN COVERAGE TO PRECLUDE
MENTIONING PRECIPITATION IN TAFMSL. OTHERWISE, A LOWER DECK OF
BROKEN STRATOCU WILL SPREAD NORTHWESTWARD IN THE WAKE OF THE
BOUNDARY, PROVIDING VFR CIGS ARND 5 KFT THAT SHOULD PERSIST THRU
EARLY-MID AFTN TUE BEFORE DISPERSING. SE SURFACE FLOW WILL
INCREASE TO 10G18 KTS BEGINNING ARND 14Z, BUT SHOULD SUBSIDE LATE
IN THE 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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