772
FXUS64 KHUN 051931
AFDHUN
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HUNTSVILLE AL
231 PM CDT WED AUG 5 2026
..NEW NEAR TERM
KEY MESSAGES
UPDATED AT 1142 AM CDT WED AUG 5 2026
- A LOW-MEDIUM COVERAGE OF SHOWERS AND THUNDERSTORMS IS EXPECTED
TODAY, RANGING FROM 10-30% IN NORTHWEST AL TO 40-60% ELSEWHERE.
OCCASIONAL LIGHTNING AND LOCALLY HEAVY RAINFALL WILL BE THE
MAIN STORM IMPACTS.
- COVERAGE OF AFTERNOON SHOWERS AND THUNDERSTORMS WILL BE
SLIGHTLY LOWER ON THURSDAY/FRIDAY (AND MAINLY FOCUSED IN THE
HIGHER TERRAIN OF THE EAST). HOWEVER, A LOW-MEDIUM (20-60%)
CHANCE FOR DIURNAL CONVECTION WILL CONTINUE EACH DAY THROUGH
WEDNESDAY.
- NWS HEAT RISK HIGHLIGHTS MODERATE (LEVEL 2 OF 4) HEAT IMPACTS
ACROSS THE TENNESSEE VALLEY FROM THURSDAY-WEDNESDAY. THESE
VALUES WILL INCREASE TO MAJOR (LEVEL 3 OF 4) FOR PARTS OF THE
AREA BEGINNING FRIDAY.
NEAR TERM
(REST OF TODAY AND TONIGHT)
ISSUED AT 231 PM CDT WED AUG 5 2026
THERE HAVE BEEN NO SIGNIFICANT CHANGES TO FORECAST REASONING IN
THE NEAR TERM THIS AFTERNOON. CURRENT THINKING IS THAT CLUSTERS OF
SHOWERS (AND SOME THUNDERSTORMS) WILL CONTINUE TO DRIFT VERY
SLOWLY EAST-SOUTHEASTWARD FOR THE REMAINDER OF THE AFTERNOON (WITH
COVERAGE SLIGHTLY LOWER ACROSS NORTHWEST AL COMPARED TO THE
REMAINDER OF THE CWFA). DUE TO SLOW CELL MOTIONS AND ABUNDANT
MOISTURE IN THE LOWER TROPOSPHERE, LOCALLY HEAVY RAINFALL (WHICH
MAY PRODUCE SIGNIFICANT PONDING OF WATER ON ROADS AND MINOR
FLOODING) WILL BE THE MOST SIGNIFICANT IMPACT, ALONG WITH
OCCASIONAL LIGHTNING. IT STILL APPEARS AS IF CONVECTION WILL
DISSIPATE BETWEEN 2-4Z (IF NOT A BIT EARLIER), WITH CLEARING SKIES
AND LIGHT SSE WINDS SUPPORTING THE DEVELOPMENT OF PATCHY MIST/FOG
AS TEMPS FALL INTO THE U60S-M70S.
PREVIOUS DISCUSSION:
IN THE MID/UPPER-LEVELS, A CUTOFF LOW (INITIALLY CENTERED ACROSS
SOUTHEASTERN TN) WILL DEGENERATE INTO A HIGHLY-SHEARED WAVE
EXTENDING FROM THE CENTRAL APPALACHIANS INTO NORTHERN GA BY 12Z
THURSDAY. AT THE SURFACE, AN INCREASINGLY DIFFUSE TROUGH AND
RELATED STREAMLINE CONFLUENCE AXIS IS PREDICTED TO REMAIN NEARLY
STATIONARY FROM WESTERN PORTIONS OF NORTH AL/MIDDLE TN INTO
CENTRAL KY TODAY. HOWEVER, THIS FEATURE WILL BECOME INCREASINGLY
MASKED TONIGHT AS SSE FLOW IN THE LOW-LEVELS BECOMES MORE
ESTABLISHED DUE TO THE WESTWARD EXPANSION OF A BERMUDA RIDGE INTO
THE SOUTHEASTERN CONUS AND NORTHWEST GULF COAST.
CURRENT EXPECTATIONS ARE FOR ONGOING SHOWER ACTIVITY ACROSS THE
SOUTHEASTERN PORTION OF THE CWFA TO EXPAND IN COVERAGE OVER THE
COURSE OF THE DAY, WITH GREATEST SPATIAL CONCENTRATION EXTENDING
FROM EAST-CENTRAL AL NORTHEASTWARD INTO THE CENTRAL APPALACHIANS
(WHERE LOWER HEIGHTS ALOFT WILL PROVIDE A MORE FAVORABLE
ENVIRONMENT FOR UPDRAFT GROWTH). ADDITIONAL SHOWERS ARE LIKELY TO
EVOLVE IN THE VICINITY OF THE REMNANT SURFACE TROUGH, WITH AN
INCREASING RISK FOR THUNDERSTORMS REGION-WIDE THIS AFTERNOON AS
TEMPS WARM INTO THE 85-90F RANGE (SUPPORTING MLCAPE OF 1500-2000
J/KG). WITH STEERING CURRENTS WEAKER TODAY AND ORIENTED FROM NW-
TO-SE, WE EXPECT VERY SLOW EAST-SOUTHEASTWARD CELL MOTIONS WHICH
(ALONG WITH PWAT VALUES OF 1.6-1.8") WILL SUPPORT LIGHTNING AND
LOCALLY HEAVY RAINFALL/MINOR FLOODING AS THE GREATEST CONVECTIVE
IMPACTS.
GUIDANCE FROM THE MOST RECENT SUITE OF CAMS SUGGESTS THAT
LINGERING WEAK CONVECTION WILL DIMINISH EARLIER THAN YESTERDAY
EVENING (BY 2-4Z AT THE LATEST), WHICH APPEARS REASONABLE GIVEN
THE REDUCTION IN LOW-LEVEL FORCING. WITH LIGHT SSE FLOW SUPPORTING
A MINOR INCREASE IN OVERNIGHT LOWS (INTO THE U60S-M70S),
DEVELOPMENT OF PATCHY FOG IS MORE UNCERTAIN, BUT SOME EARLY
MORNING VISIBILITY REDUCTIONS MAY STILL OCCUR IN LOCATIONS THAT
EXPERIENCE WETTING RAINFALL TODAY.
SHORT TERM
(THURSDAY THROUGH FRIDAY NIGHT)
ISSUED AT 1142 AM CDT WED AUG 5 2026
THROUGHOUT THE FIRST HALF OF THE SHORT TERM PERIOD (THURSDAY AND
THURSDAY NIGHT), A MID-LEVEL RIDGE WILL EXPAND EASTWARD ACROSS THE
TN VALLEY FROM A STRONG ANTICYCLONE CENTERED ACROSS AZ/NM.
ALTHOUGH RISING HEIGHTS ALOFT AND LACK OF A SURFACE BOUNDARY WILL
PROVIDE AN ENVIRONMENT LESS CONDUCIVE FOR CONVECTION, STRONG
HEATING OF A MOIST BOUNDARY LAYER WILL RESULT IN SCATTERED
AFTERNOON SHOWERS AND THUNDERSTORMS TOMORROW ACROSS MUCH OF THE
CENTRAL GULF COAST STATES AND SOUTHEASTERN CONUS, WITH THE
GREATEST COVERAGE ACROSS OUR FORECAST AREA EXPECTED IN ZONES OF
OROGRAPHIC LIFT ACROSS NORTHEAST AL/SOUTHERN TN. WITH FORECAST
SOUNDINGS INDICATING SIMILAR VALUES OF CAPE/PWAT COMPARED TO TODAY
AND WEAK/UNORGANIZED DEEP-LAYER FLOW, WE EXPECT SIMILAR THREATS
FOR LIGHTNING AND LOCALLY HEAVY RAINFALL.
SHORT TERM MODEL CONSENSUS SUGGESTS THAT A GRADUAL INCREASE IN
SOUTHWESTERLY FLOW ALOFT WILL BEGIN ON FRIDAY AND CONTINUE INTO
FRIDAY NIGHT AS A SHORTWAVE TROUGH DROPS SOUTHEASTWARD FROM THE MO
VALLEY INTO THE LOWER OH VALLEY WITHIN A BROAD WEAKNESS IN THE
SUBTROPICAL RIDGE ACROSS THE CENTRAL GULF COAST. ALTHOUGH THERE IS
SOME CONCERN THAT AN MCV (ORIGINATING FROM WIDESPREAD CONVECTION
THURSDAY NIGHT ACROSS EASTERN KS/WESTERN MO) MAY GENERATE A HIGHER
COVERAGE OF AFTERNOON SHOWERS AND STORMS ACROSS OUR FORECAST AREA
ON FRIDAY, THIS APPEARS MORE LIKELY TO OCCUR TO OUR NORTHWEST AND
WE WILL ADVERTISE POPS SIMILAR TO THURSDAY (RANGING FROM 10-20%
WEST TO 40-50% EAST). A FEW SHOWERS AND THUNDERSTORMS MAY ALSO
CONTINUE ON FRIDAY NIGHT/EARLY SATURDAY MORNING IN THE
STRENGTHENING DEEP-LAYER WARM ADVECTION REGIME AHEAD OF THE
SHORTWAVE TROUGH, BUT COVERAGE WILL LIKELY BE HIGHEST TO OUR
NORTHEAST.
LONG TERM
(SATURDAY THROUGH TUESDAY)
ISSUED AT 951 PM CDT TUE AUG 4 2026
AN UPPER LEVEL SHORTWAVE TROUGH LOOKS TO SWEEP OVER THE
MISSISSIPPI RIVER VALLEY AND TOWARDS THE NORTHEASTERN U.S. ON
SATURDAY. BY SUNDAY AND THROUGH EARLY NEXT WEEK, UPPER RIDGING IS
SHOWN TO BUILD OVER THE SOUTHERN PLAINS AND SOUTHEASTERN U.S.
MEANWHILE, SURFACE HIGH PRESSURE IS EXPECTED TO REMAIN PARKED OVER
THE APPALACHIANS FOR MUCH OF THIS TIME. THIS FEATURE DOES SHIFT
SOUTH OVER THE NORTHERN GULF COAST BY TUESDAY, HOWEVER. OVERALL,
ANTICIPATING DAILY CHANCES OF SHOWERS AND STORMS, MAINLY DURING
THE AFTERNOON AND EVENING HOURS. EXPECT HIGHER CHANCES OF SHOWERS
AND STORMS ON SATURDAY DUE TO THE AFOREMENTIONED UPPER SHORTWAVE
TROUGH SWINGING OVER THE REGION, WITH CHANCES DECREASING FOR
SUNDAY THROUGH TUESDAY. PWATS WILL REMAIN ELEVATED, BUT BULK SHEAR
WILL LIKELY BE 20 KNOTS OR LESS THROUGHOUT THE PERIOD. THEREFORE,
SEVERE WEATHER IS NOT ANTICIPATED, BUT FREQUENT LIGHTNING AND
HEAVY RAIN WILL BE THE MAIN THREATS WITH ANY STORMS.
AS FOR TEMPERATURES, HIGHS IN THE UPPER 80S TO LOWER 90S WITH
LOWS IN THE LOWER TO MID 70S WILL BE COMMON. WITH ELEVATED
MOISTURE PERSISTING, AFTERNOON HEAT INDEX VALUES ARE FORECAST TO
MOSTLY RANGE BETWEEN 98-104 DEGREES THROUGH THE WEEKEND, THEN
INCREASE A BIT BY EARLY NEXT WEEK AS RAIN CHANCES DECREASE. THIS
RESULTS IN A MODERATE HEATRISK FOR NORTH ALABAMA AND SOUTHERN
MIDDLE TENNESSEE THIS WEEKEND, WITH SOME LOCATIONS IN THE MAJOR
CATEGORY BY MONDAY. THIS WILL BE SOMETHING TO WATCH IN CASE HEAT
ADVISORIES BECOME NECESSARY FOR ALL OR PORTIONS OF THE LOCAL AREA.
REGARDLESS, PLEASE REMEMBER HEAT SAFETY! DRINK PLENTY OF WATER,
TAKE FREQUENT BREAKS IN THE SHADE, AND NEVER LEAVE PEOPLE OR PETS
IN VEHICLES!
AVIATION
(18Z TAFS)
ISSUED AT 1244 PM CDT WED AUG 5 2026
SCATTERED-NUMEROUS SHRA AND SOME TSRA WILL CONTINUE TO IMPACT
MUCH OF NORTH AL THIS AFTN, WITH SLOW CELL MOTIONS TO THE SE-ESE
ANTICIPATED. BASED ON CURRENT RADAR DATA, WE WILL INCLUDE TEMPO
GROUPS FOR BOTH HSV AND MSL THRU 22Z, WITH TSRA A GREATER NEAR
TERM CONCERN AT HSV. ASIDE FROM PERIODS OF HVY RAIN RESULTING IN
MVFR CIG/VSBY REDUCTIONS, OCCASIONAL LIGHTNING WILL BE THE
GREATEST IMPACT FROM THIS ACTIVITY. DIURNAL CONVECTION WILL LIKELY
DISSIPATE ENTIRELY BY 2-4Z (IF NOT A BIT SOONER), SETTING THE
STAGE FOR DEVELOPMENT OF PATCHY BR/FG (ESPECIALLY IN LOCATIONS
THAT RECEIVE WETTING RAINS TODAY). HOWEVER, WITH A LGT SSE FLOW
EXPECTED TO BECOME ESTABLISHED OVERNIGHT, WE WILL NOT MENTION VSBY
REDUCTIONS IN THE FORECAST ATTM. FEW-SCT CU WILL DEVELOP ONCE
AGAIN BY THE END OF THE TAF PERIOD, ALONG WITH A LIGHT SSW WIND OF
5-10 KTS.
HUN WATCHES/WARNINGS/ADVISORIES
AL...NONE.
TN...NONE.
NEAR TERM...70/DD
SHORT TERM...70/DD
LONG TERM...26
AVIATION...70/DD
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