498
FXUS64 KHUN 181830
AFDHUN
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HUNTSVILLE AL
130 PM CDT SAT JUL 18 2026
..NEW NEAR TERM
KEY MESSAGES
UPDATED AT 130 PM CDT SAT JUL 18 2026
- MODERATE (LEVEL 2/4) TO MAJOR (LEVEL 3/4) HEAT RISK WILL BUILD
INTO THE TENNESSEE VALLEY THIS WEEKEND THROUGH THE MIDDLE OF
NEXT WEEK, WITH PEAK HEAT INDEX VALUES BETWEEN 100 TO 105
DEGREES LIKELY, AND POTENTIALLY BETWEEN 105-109 DEGREES IN SOME
LOCATIONS MONDAY AND TUESDAY.
- DAILY THUNDERSTORM CHANCES WILL CONTINUE OVER THE WEEKEND INTO
EARLY NEXT WEEK. A FEW STORMS COULD BECOME STRONG TO MARGINALLY
SEVERE, ESPECIALLY ON SUNDAY. GUSTY TO DAMAGING WINDS AND
LOCALLY HEAVY RAINFALL WILL BE THE MAIN THREATS.
- SLIGHTLY COOLER AND LESS HUMID AIR IS EXPECTED IN THE MIDDLE
AND LATTER PORTIONS OF NEXT WEEK.
NEAR TERM
(TONIGHT)
ISSUED AT 130 PM CDT SAT JUL 18 2026
A FEW REMNANT OUTFLOW BOUNDARIES HAVE SERVED AS A FOCUS FOR SOME
CLUSTERS OF THUNDERSTORMS ALONG THE AL/GA BORDER AND ACROSS
PORTIONS OF NORTHWEST ALABAMA EARLY THIS AFTERNOON. THERE IS
PLENTY OF INSTABILITY TO WORK WITH MLCAPE VALUES AROUND 2000-3000
J/KG COUPLED WITH LOW-LEVEL LAPSE RATES AROUND 7.5 C/KM. DCAPE
VALUES ARE A LITTLE MORE MODEST, BUT STILL APPRECIABLE (AROUND
600-700 J/KG). THESE VALUES WILL SUPPORT AT LEAST A FEW LOCALIZED
STRONG STORMS THROUGH THE EARLY EVENING HOURS. RADAR COVERAGE AT
18Z WAS A TOUCH HIGHER THAN FORECAST, SO HAVE ADJUSTED POPS UP TO
30-50% FOR THE REMAINDER OF THE AFTERNOON. OTHERWISE, HEAT WILL
REMAIN THE BIGGEST CONCERN THROUGH THE REMAINDER OF THE DAY WITH
PEAK HEAT INDEX VALUES BETWEEN 100-105 DEGREES.
THIS ACTIVITY WILL WANE AFTER SUNSET, WITH TRANQUIL CONDITIONS
AGAIN FORECAST OVERNIGHT (SAVE FOR SOME PATCHY FOG IN AREAS THAT
RECEIVE RAINFALL).
SHORT TERM
(SUNDAY THROUGH TUESDAY)
ISSUED AT 912 AM CDT SAT JUL 18 2026
A MODERATE (LEVEL 2/4) TO MAJOR (LEVEL 3/4) HEAT RISK WILL BE THE
MAIN CONCERN IN THE FORECAST EARLY NEXT WEEK WITH HIGH PRESSURE
BUILDING IN AND A TROPICAL-LIKE AIR MASS IN PLACE UNDER THE RIDGE.
THIS WILL CREATE DAYTIME HIGHS IN THE LOW TO MID 90S EACH DAY,
WITH HEAT INDEX VALUES BETWEEN 100-105 DEGREES ACROSS THE ENTIRE
TENNESSEE VALLEY (AND SEVERAL LOCATIONS THAT REACH THE 105-109
DEGREE RANGE BY MONDAY AND ESPECIALLY TUESDAY). HEAT PRODUCTS MAY
BE NEEDED BY EARLY NEXT WEEK AND WE WILL CONTINUE TO MONITOR
FORECAST TRENDS. REGARDLESS, IT WILL BE IMPORTANT TO PRACTICE HEAT
SAFETY NEXT WEEK, ESPECIALLY IF YOU HAVE OUTDOOR PLANS!
DAILY THUNDERSTORM CHANCES WILL EXIST EACH AFTERNOON, THANKS TO
DIURNAL HEATING AND RESIDUAL OUTFLOW BOUNDARIES IN PLACE. THE
GREATEST COVERAGE WILL LIKELY OCCUR ON SUNDAY AS A WEAK SHORTWAVE
CLIPS THE NORTHEAST EDGE OF THE RIDGE, WITH MEDIUM (40-60%)
CHANCES FOR SHOWERS/STORMS. MLCAPE VALUES OF 2500-3000 J/KG, DCAPE
VALUES OVER 1000 J/KG, AND LOW-LEVEL LAPSE RATES OF 8-9 C/KM WILL
FAVOR AT LEAST A FEW STRONG TO MARGINALLY SEVERE STORMS CAPABLE OF
PRODUCING DAMAGING WINDS AND HEAVY RAINFALL. SPC HAS PLACED THE
ENTIRE TENNESSEE VALLEY UNDER A MARGINAL RISK (LEVEL 1/5) FOR
SEVERE WEATHER FOR THIS REASON.
AS THE RIDGE BUILDS EAST, POPS WILL LOWER TO 30-50% ON MONDAY AND
20-40% ON TUESDAY THANKS TO STRONGER SUBSIDENCE AND A LACK OF
FORCING. EACH DAY THERE WILL BE A LOW CHANCE OF A COUPLE STORMS
BECOMING LOCALLY STRONG TO MARGINALLY SEVERE, WITH GUSTY/DAMAGING
WINDS AND HEAVY DOWNPOURS THE MAIN THREAT.
LONG TERM
(MONDAY NIGHT THROUGH FRIDAY)
ISSUED AT 858 PM CDT FRI JUL 17 2026
THE WEATHER PATTERN DURING THE DAY 4-7 PERIOD WILL INVOLVE A STRONG
TROUGH DEVELOPING OVER THE GREAT LAKES INTO THE MID ATLANTIC AND NEW
ENGLAND STATES AND AN UPPER RIDGE BUILDING OVER THE SOUTHERN PLAINS.
A LOW LEVEL THERMAL RIDGE (850 MB TEMPS OF 20-23C) WILL ARRIVE ON
TUESDAY, MAKING FOR A HOT AND HUMID DAY. HEAT RISK WILL REACH THE
MAJOR CATEGORY (3 OUT OF 4) FOR MUCH OF THE TN VALLEY. HIGH
TEMPERATURES IN THE LOWER TO MIDDLE 90S, HEAT INDEX VALUES OF 100 TO
~105F AND WBGTS IN THE MIDDLE TO UPPER 80S ARE EXPECTED. A SHORTWAVE
TROUGH AXIS AND COOL FRONT WILL DROP SOUTHEAST TOWARD THE TN VALLEY
THROUGH THE TN VALLEY ON WEDNESDAY, BRINGING A LOW CHANCE OF
THUNDERSTORMS. BEHIND THE FRONT, SLIGHTLY COOLER AIR WITH HIGHS IN
THE UPPER 80S TO LOWER 90S ARE EXPECTED WEDNESDAY, WITH MIDDLE TO
UPPER 80S ON THURSDAY AFTER MORNING LOWS IN THE MIDDLE TO UPPER 60S.
ANOTHER FRIDAY MORNING LOWS IN THE 60S, AFTERNOON HIGHS WILL BE NEAR
NORMAL AND IN THE UPPER 80S TO AROUND 90. AND EVEN BETTER, DEW
POINTS WILL DROP INTO THE MIDDLE TO UPPER 60S FRIDAY.
AVIATION
(18Z TAFS)
ISSUED AT 1142 AM CDT SAT JUL 18 2026
VFR CONDITIONS WILL BE THE PREDOMINANT FLIGHT CATEGORY AT EACH
TERMINAL THROUGH THE PERIOD, WITH LIGHT WINDS. A FEW TSRA WILL
DEVELOP ACROSS THE TN VALLEY THIS AFTERNOON, BUT CONFIDENCE WAS
TOO LOW IN COVERAGE TO MENTION IN THE TAF AT THIS TIME. HOWEVER,
ANY STORMS THAT DO DEVELOP WILL DISSIPATE BY 00-01Z, WITH VFR
CONDITIONS PREVAILING THROUGH THE REMAINDER OF THE PERIOD.
HUN WATCHES/WARNINGS/ADVISORIES
AL...NONE.
TN...NONE.
NEAR TERM...AMP.24
SHORT TERM....AMP
LONG TERM....17
AVIATION...AMP
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