069
FXUS64 KHUN 121857
AFDHUN
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HUNTSVILLE AL
157 PM CDT WED AUG 12 2026
..NEW NEAR TERM
KEY MESSAGES
UPDATED AT 157 PM CDT WED AUG 12 2026
- A HEAT ADVISORY IS IN EFFECT FOR THE ENTIRE FORECAST AREA TODAY
THROUGH SUNDAY, WITH EXTENSIONS LIKELY INTO THE MIDDLE OF NEXT
WEEK.
- A LOW CONDITIONAL THREAT FOR STRONG TO SEVERE STORMS WILL EXIST
ONCE AGAIN THIS AFTERNOON.
NEAR TERM
(TONIGHT)
ISSUED AT 157 PM CDT WED AUG 12 2026
DIURNAL HEATING HAS TRIGGERED SEVERAL SHOWERS AND THUNDERSTORMS
ACROSS THE TENNESSEE VALLEY A LITTLE EARLIER THAN ANTICIPATED
TODAY. THIS ACTIVITY IS SOLELY TIED TO DIURNAL HEATING AND WITH
FAVORABLE THERMODYNAMICS ALLOWING ANY OF THESE STORMS TO BECOME
STRONG TO MARGINALLY SEVERE THROUGH THIS EVENING. DCAPE VALUES
AROUND 1000-1200 J/KG WOULD FAVOR DAMAGING DOWNBURSTS AS THE
PRIMARY THREAT. ADDITIONALLY, PWATS OVER 2" AND SLOW STORM
MOTIONS WILL ALSO RESULT IN A LOCALLY HEAVY RAINFALL AND FLASH
FLOODING CONCERN (WITH LOCATIONS THAT DO RECEIVE REPEATED
RAINFALL). GIVEN THE SLIGHTLY HIGHER COVERAGE, HAVE INCREASED
POPS TO 30-50% THROUGH EARLY THIS EVENING.
ADDITIONALLY, WE'LL AGAIN NEED TO WATCH CONVECTION UPSTREAM OVER
THE OHIO VALLEY IN ILLINOIS AND INDIANA. IF IT HOLDS TOGETHER, THE
STEERING FLOW COULD PUSH A FEW CLUSTERS OF ELEVATED, SUBSEVERE
STORMS THROUGH THE AREA OVERNIGHT. A FEW HI-RES SOLUTIONS NOW SHOW
SOME OF THIS CONVECTION CLIPPING THE AREA WHICH MAKES SENSE GIVEN
THE CURRENT LOCATION OF STORMS TO THE NORTHWEST AND THE POSITION
OF SYNOPTIC FEATURES. THUS, WILL LEAVE A LOW CHANCE FOR SHOWERS
AND ELEVATED STORMS OVERNIGHT, ESPECIALLY IN THE EASTERN HALF OF
OUR AREA.
FINALLY, HEAT WILL CONTINUE TO BE CONCERN NOT ONLY DURING THE
AFTERNOON, BUT ALSO OVERNIGHT AS THERE WILL BE VERY LIMITED
RELIEF (WITH LOWS IN THE MID TO UPPER 70S). THE HEAT ADVISORY
REMAINS IN EFFECT FOR THE ENTIRE TENNESSEE VALLEY REGION.
SHORT TERM
(THURSDAY THROUGH FRIDAY NIGHT)
ISSUED AT 832 AM CDT WED AUG 12 2026
A LARGE AREA OF HIGH PRESSURE WILL BUILD INTO THE TENNESSEE
VALLEY FROM THE WEST LATE THIS WEEK, WITH A HEAT DOME UNDERNEATH
THIS RIDGE SUBSEQUENTLY SHIFTING EAST INTO THE REGION. AMPLE
SUNSHINE WILL WARM TEMPERATURES WILL THE MID TO UPPER 90S AND
COMBINE WITH DEWPOINTS IN THE MID TO UPPER 70S WILL CREATE
DANGEROUS HEAT INDICES IN THE 105-110 DEGREE RANGE. NWS HEAT RISK
HIGHLIGHTS A MAJOR RISK (LEVEL 3/4) OF HEAT RELATED IMPACTS
DURING THE DAY (AND OVERNIGHT AS LOWS WILL REMAIN IN THE MID TO
UPPER 70S). THUS, A HEAT ADVISORY IS IN EFFECT FOR THIS ENTIRE
PERIOD AND NOW RUNS THROUGH 7 PM SUNDAY. ANOTHER LOW CHANCE
(20-30%) OF SHOWERS AND STORMS IS FORECAST AGAIN THURSDAY
AFTERNOON, BUT BY FRIDAY STRONG SUBSIDENCE FROM THE RIDGE SHOULD
PREVENT ANY PULSE CONVECTION FROM FORMING AND POPS WILL DROP TO
BELOW 10%.
LONG TERM
(SATURDAY THROUGH TUESDAY)
ISSUED AT 1045 PM CDT TUE AUG 11 2026
EXTENDED RANGE DATA FROM THE LATEST SUITE OF GLOBAL MODELS IS IN
GENERAL AGREEMENT THAT A SUBTROPICAL HIGH (CENTERED FROM THE LOWER
MS VALLEY TO THE SOUTHEASTERN ATLANTIC COAST) WILL CONTINUE TO
STRENGTHEN THIS WEEKEND, WITH GEOPOTENTIAL HEIGHTS PERHAPS
REACHING 600 DAM. THUS, EXCESSIVE HEAT WILL CONTINUE TO BE A
CONCERN ACROSS THE TN VALLEY, WITH HIGHS REMAINING IN THE M-U 90S
FROM SATURDAY-MONDAY (AND PERHAPS EXCEEDING 100F IN SEVERAL
LOCATIONS ON BOTH SUNDAY AND MONDAY AFTERNOONS). ALTHOUGH A FEW
AFTERNOON STORMS MAY OCCUR ON BOTH SATURDAY AND SUNDAY (PRIMARILY
IN THE HIGHER TERRAIN OF NORTHEAST AL), RAIN CHANCES WILL REMAIN
LOW AND THERE IS A VERY HIGH CHANCE THAT THE PRE-EXISTING HEAT
ADVISORY WILL NEED TO BE EXTENDED THROUGH MONDAY, PERHAPS WITH AN
UPGRADE TO AN EXTREME HEAT WARNING DUE TO HEAT INDEX READINGS
SURPASSING 110F. BY LATE IN THE FORECAST PERIOD, THERE ARE
INDICATIONS THAT THE SUBTROPICAL HIGH MAY BEGIN TO RETROGRADE INTO
THE SOUTHERN HIGH PLAINS, PERHAPS ALLOWING NW FLOW ALOFT TO
BECOME REESTABLISHED ACROSS OUR REGION BY MONDAY/TUESDAY. SHOULD
THIS OCCUR, A WEAK COLD FRONT MAY BRING A BROKEN LINE OF SHOWERS
AND THUNDERSTORMS TO THE REGION MONDAY EVENING, FOLLOWED BY A
SLIGHT DROP IN TEMPERATURES/DEWPOINTS ON TUESDAY.
AVIATION
(18Z TAFS)
ISSUED AT 1132 AM CDT WED AUG 12 2026
VFR CONDITIONS WILL BE THE PREDOMINANT FLIGHT CATEGORY AT EACH
TERMINAL THROUGH THE PERIOD. A LOW CHANCE FOR A TSRA IS FORECAST
BETWEEN 20-00Z AND HAVE HANDLED THIS WITH A PROB GROUP. SHOULD A
STORM IMPACT EITHER TERMINAL, LOCALIZED MVFR CONDITIONS DUE TO
REDUCED VISIBILITIES AND CEILINGS MAY OCCUR AND AWWS WILL BE
NEEDED.
CLIMATE
ISSUED AT 157 PM CDT WED AUG 12 2026
THE CLIMATE PREDICTION CENTER HAS INCLUDED MUCH OF NORTHERN
ALABAMA IN A HIGH RISK FOR MUCH ABOVE NORMAL TEMPERATURES AND
MUCH OF SOUTHERN MIDDLE TENNESSEE AND FAR NORTHEAST ALABAMA IN A
MODERATE RISK FOR MUCH ABOVE NORMAL TEMPERATURES ON AUGUST 20TH
AND 21ST.
ALL OF NORTHERN ALABAMA AND SOUTHERN MIDDLE TENNESSEE IS ALSO
INCLUDED IN A MODERATE RISK FOR MUCH ABOVE NORMAL TEMPERATURES
AUGUST 22ND AND 23RD.
THEREFORE, THERE IS A 40-60% CHANCE IN THE MODERATE RISK
LOCATIONS AND A 60-80% CHANCE FOR THOSE IN THE HIGH RISK AREAS FOR
TEMPERATURES ABOVE 95 TO 97 DEGREES F AND HEAT INDEX VALUES ABOVE
105 TO 110 DEGREES F DURING THIS PERIOD.
MORE INFORMATION ON THE CPC U.S. HAZARDS OUTLOOK CAN BE FOUND AT:
HTTPS://WWW.CPC.NCEP.NOAA.GOV/PRODUCTS/PREDICTIONS/THREATS/THREATS.PHP
HUN WATCHES/WARNINGS/ADVISORIES
AL...HEAT ADVISORY UNTIL 7 PM CDT SUNDAY FOR ALZ001>010-016.
TN...HEAT ADVISORY UNTIL 7 PM CDT SUNDAY FOR TNZ076-096-097.
NEAR TERM...AMP.24
SHORT TERM....AMP
LONG TERM....70
AVIATION...AMP
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