771
FXUS64 KHUN 131308
AFDHUN
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HUNTSVILLE AL
808 AM CDT THU AUG 13 2026
..NEW NEAR TERM, SHORT TERM
KEY MESSAGES
UPDATED AT 801 AM CDT THU AUG 13 2026
- A HEAT ADVISORY REMAINS IN EFFECT FOR THE ENTIRE FORECAST AREA
THROUGH SUNDAY, WITH EXTENSIONS LIKELY INTO THE MIDDLE OF NEXT
WEEK.
- A CONDITIONAL, VERY LOW (10-20%) CHANCE FOR A FEW THUNDERSTORMS
EACH AFTERNOON/EVENING THROUGH SATURDAY. A COUPLE STORMS MAY
BECOME STRONG TO MARGINALLY SEVERE WITH LOCALIZED DAMAGING
WINDS AND HEAVY RAINFALL THE MAIN THREATS.
NEAR TERM
(REST OF TODAY AND TONIGHT)
ISSUED AT 808 AM CDT THU AUG 13 2026
DANGEROUS HEAT WILL CONTINUE TO IMPACT THE TENNESSEE VALLEY TODAY
AS A STRONG UPPER-RIDGE OF HIGH PRESSURE CONTINUES TO BUILD INTO
THE REGION FROM THE WEST. AMPLE HEATING WILL PUSH HIGHS INTO THE
MID 90S IN MOST LOCATIONS BY THE AFTERNOON. THESE HOT TEMPERATURES,
COMBINED WITH DEWPOINTS IN THE MID TO UPPER 70S, WILL CREATE HEAT
INDEX VALUES BETWEEN 105-110 DEGREES THIS AFTERNOON/EVENING. NWS
HEAT RISK HIGHLIGHTS A MAJOR (LEVEL 4/5) THREAT FOR HEAT IMPACTS
ACROSS THE ENTIRE TENNESSEE VALLEY NOT ONLY TODAY, BUT OVERNIGHT
AS LOWS IN THE MID TO UPPER 70S WILL BE COMMON, PROVIDING LIMITED
RELIEF. A HEAT ADVISORY REMAINS IN EFFECT FOR THE ENTIRE REGION.
IN ADDITION TO THE HEAT THREAT, THERE IS A LOW, CONDITIONAL
THREAT (10-20%) FOR A FEW DIURNALLY DRIVEN PULSE STORMS IN THE
AFTERNOON AND EVENING HOURS (1-9 PM), ESPECIALLY IN LOCATIONS
ALONG AND EAST OF I-65. 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.
SHORT TERM
(FRIDAY THROUGH SATURDAY NIGHT)
ISSUED AT 808 AM CDT THU AUG 13 2026
THE UPPER RIDGE WILL BUILD EAST INTO THE TENNESSEE VALLEY FRIDAY
INTO THE WEEKEND, WITH A HEAT DOME UNDERNEATH THIS RIDGE
SUBSEQUENTLY SHIFTING EAST INTO THE REGION. STRONG SUBSIDENCE
(SUPPORTED BY MODEL SOUNDINGS) FROM THIS RIDGE WILL LARGELY
SUPPRESS CLOUD COVER AND CONVECTION EACH DAY. STRONG INSOLATION
EACH DAY WILL PUSH HIGH TEMPERATURES IN THE MID TO UPPER 90S AND
COMBINED WITH DEWPOINTS IN THE MID 70S, WILL PUSH HEAT INDEX
VALUES IN THE 105-110 RANGE AREAWIDE, WITH SOME LOCATIONS
EXCEEDING 110 DEGREES, ESPECIALLY ON SATURDAY. SHOULD THESE TRENDS
CONTINUE AN EXTREME HEAT WARNING MAY NEED TO BE CONSIDERED IN A
LATER UPDATE. A HEAT ADVISORY REMAINS IN EFFECT THROUGH 7 PM
SUNDAY. OTHERWISE, A VERY LOW CHANCE (10-15%) FOR AN AFTERNOON
STORM OR TWO WILL EXIST BOTH DAY, MAINLY ACROSS FAR NORTHEAST
ALABAMA.
LONG TERM
(SUNDAY THROUGH WEDNESDAY)
ISSUED AT 1114 PM CDT WED AUG 12 2026
GLOBAL MODELS CONTINUE TO INDICATE THAT AN INTENSE MID-LEVEL
SUBTROPICAL HIGH (INITIALLY CENTERED ACROSS THE GULF COAST STATES)
WILL RETROGRADE WESTWARD INTO AZ/NM EARLY IN THE EXTENDED PERIOD,
AS A NORTHERN STREAM SHORTWAVE TROUGH DIGS SOUTHEASTWARD ACROSS
THE CANADIAN PRAIRIE. THIS EVOLUTION WILL ALLOW WNW FLOW ALOFT OF
10-20 KNOTS TO BECOME ESTABLISHED ACROSS THE REGION ONCE AGAIN BY
MONDAY, PERHAPS ALLOWING A WEAK COLD FRONT TO DROP SOUTHWARD INTO
THE REGION AT SOME POINT MONDAY NIGHT OR TUESDAY. PRIOR TO THE
ARRIVAL OF THE FRONT, VERY HOT AFTERNOON TEMPERATURES WILL EXIST
ON BOTH SUNDAY AND MONDAY, WITH SOME LOCATIONS LIKELY TO REACH OR
EXCEED 100F BOTH AFTERNOONS. ALTHOUGH FORECAST SOUNDINGS SUGGEST
INCREASINGLY FAVORABLE PROFILES FOR DEEP MIXING (WHICH COULD
RESULT IN DEWPOINTS PERHAPS MIXING OUT INTO THE L-M 60S ACROSS
LARGE PORTIONS OF THE FORECAST AREA BOTH DAYS), APPARENT TEMPS
SOLIDLY IN THE 105-110F RANGE SUGGEST THAT THE CURRENT HEAT
ADVISORY WILL NEED TO BE EXTENDED INTO MONDAY.
SHOULD THE WEAK COLD FRONT (MENTIONED ABOVE) INDEED ENTER THE
REGION ON MONDAY NIGHT OR TUESDAY, IT WOULD LIKELY BE ACCOMPANIED
BY A BROKEN BAND OF CONVECTION THAT MAY STRUGGLE TO SURVIVE AS IT
ENTERS A WELL-MIXED AIRMASS (WITH LOWER MOISTURE CONTENT AND CAPE
COMPARED TO WHAT WE ARE EXPERIENCING CURRENTLY). HOWEVER, THERE IS
A HIGH DEGREE OF UNCERTAINTY REGARDING THIS SCENARIO, AND FOR
THIS REASON WE WILL ONLY ADVERTISE A LOW (10-30% POP) WITH
AFTERNOON TEMPS MERELY DROPPING BACK INTO THE L-M 90S.
AVIATION
(12Z TAFS)
ISSUED AT 639 AM CDT THU AUG 13 2026
MVFR FOG IS MAINLY AFFECTING KMSL BUT WILL NOT RULE OUT A VIS DROP
AT KHSV IN THE NEXT HOUR OR SO. OTHERWISE VFR CONDITIONS ARE
EXPECTED THROUGH THE TAF PERIOD. THERE IS LOW CONFIDENCE ON
THUNDERSTORM DEVELOPMENT TODAY AS IT WOULD RELY ON OUTFLOW
BOUNDARIES TO OUR NORTH, SO KEPT ANY TSRA OUT OF THIS TAF ISSUANCE
FOR NOW.
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.24
LONG TERM....70
AVIATION...JMS
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