264
FXUS64 KHUN 210524
AFDHUN
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HUNTSVILLE AL
1224 AM CDT TUE JUL 21 2026
..NEW AVIATION
KEY MESSAGES
UPDATED AT 905 PM CDT MON JUL 20 2026
- A HEAT ADVISORY IS IN EFFECT FOR MOST OF THE TENNESSEE VALLEY
THROUGH TUESDAY AT 8 PM.
- MODERATE (LEVEL 2/4) TO MAJOR (LEVEL 3/4) HEAT RISK WILL BUILD
INTO THE TENNESSEE VALLEY THROUGH THE MIDDLE OF THE WEEK, WITH
PEAK HEAT INDEX VALUES BETWEEN 100 TO 109 DEGREES LIKELY IN
MOST LOCATIONS TODAY AND TUESDAY.
- DAILY THUNDERSTORM CHANCES WILL CONTINUE INTO EARLY THIS WEEK.
A FEW STORMS COULD BECOME STRONG TO MARGINALLY SEVERE TUESDAY
EVENING/NIGHT. GUSTY TO DAMAGING WINDS, FREQUENT LIGHTNING, AND
LOCALLY HEAVY RAINFALL WILL BE THE MAIN THREATS.
NEAR TERM
(REST OF TONIGHT AND TUESDAY)
ISSUED AT 905 PM CDT MON JUL 20 2026
SHOWERS AND STORMS HAVE GREATLY WANED NOW THAT THE SUN HAS SET.
UNDER HIGH PRESSURE INFLUENCE, WINDS WILL CALM OVERNIGHT. CALM
WINDS PAIRED WITH LOW DEW POINT DEPRESSION WILL ALLOW FOR PATCHY
FOG FORMATION THROUGH THE EARLY MORNING HOURS.
AS WE HEAD INTO THE DAY TOMORROW, MID LEVEL RIDGING WILL PUSH EAST
INTO THE TN VALLEY. THIS WILL SUPPORT TEMPERATURES PEAKING A
DEGREE OR TWO HOTTER THAN TODAY TO AROUND 95 DEGREES.
ADDITIONALLY, THE EASTWARD MOTION OF THE RIDGE WILL WORK TO
SUPPRESS CLOUD FORMATION AND RAIN CHANCES LEAVING DRY AND CLEAR
CONDITIONS TUESDAY AFTERNOON. WITH DEW POINTS REMAINING IN THE MID
70S, HEAT WILL CONTINUE TO BE A CONCERN WITH TOMORROW AFTERNOON
LOOKING LIKE THE HOTTEST DAY OF THE WEEK. HEAT INDICES LOOK TO
SOAR ABOVE 105 WITH HEAT RISK REACHING LEVEL 3/4 FOR A MAJORITY OF
THE AREA. AS SUCH, A HEAT ADVISORY REMAINS IN EFFECT FOR
EVERYWHERE EXCEPT DEKALB COUNTY (WHERE ELEVATION LOOKS TO KEEP
THINGS A FEW DEGREES COOLER) THROUGH 8 PM TOMORROW. PLEASE MAKE
SURE TO PRACTICE PROPER HEAT SAFETY.
SHORT TERM
(TUESDAY NIGHT THROUGH THURSDAY)
ISSUED AT 905 PM CDT MON JUL 20 2026
AS THE SUNSETS, STORMS WILL LIKELY BE ON THE HORIZON TO OUR NORTH
ALONG AN APPROACHING COLD FRONT. MODELS MAINTAIN A LATER ARRIVAL
OF STORMS, BETWEEN 10 PM - 12 AM. FORTUNATELY, THE LATER ARRIVAL
WILL ALLOW TIME FOR INSTABILITY TO ERODE, LEAVING ONLY A FEW
HUNDRED J/KG OF CAPE BY THE TIME STORMS GET HERE. MODELS DIVERGE
ON COVERAGE OF SHOWERS AND STORMS WITH SOME DISSIPATING STORMS AS
THEY ARRIVE AND OTHER DRAGGING A BROKEN LINE OF STORMS THROUGH,
DISSIPATING AS THEY GO. WHAT IS CONSISTENT IS THE LACK OF SHEAR,
MEANING REGARDLESS OF THE ACTUAL COVERAGE OF STORMS, ANY STORMS
THAT DO MAKE IT THROUGH WILL OBTAIN ONLY A LOW SEVERE THREAT WITH
THE PRIMARY HAZARD BEING DAMAGING WINDS.
THE ACTUAL FRONT LOOKS TO PUSH THROUGH WEDNESDAY MORNING, LEAVING
DRIER AND RELATIVELY COOLER TEMPERATURES IN ITS WAKE. TEMPS ON
WEDNESDAY WILL BE RELEGATED BACK TO THE LOW 90S WITH TEMPS
DROPPING EVEN FURTHER ON THURSDAY TO THE HIGH 80S. DEW POINTS WILL
DROP THROUGH THE DAY ON WEDNESDAY WITH MID TO HIGH 60S DEW POINTS
IN PLACE BY THURSDAY MORNING. FROM LATE WEDNESDAY INTO THURSDAY,
THE AFORMENTIONED FRONT LOOKS TO STALL JUST TO OUR SOUTH. THIS
WILL KEEP SOME POST FRONTAL CLOUD COVER THROUGH THE DAY ON
THURSDAY AND ALSO SUPPORT LOW RAIN CHANCES (20-40) IN FAR SE
PORTIONS OF OUR CWA. FORTUNATELY THREATS FOR BOTH SEVERE WEATHER
AND EXCESSIVE HEAT WILL REMAIN LOW. HOWEVER, REMAINING WEATHER
AWARE AND PRACTICING PROPER HEAT SAFETY ARE ALWAYS GOOD SUMMER
PRACTICES.
LONG TERM
(THURSDAY NIGHT THROUGH MONDAY)
ISSUED AT 905 PM CDT MON JUL 20 2026
THE GENERAL UPPER LEVEL SETUP WILL CONSIST OF A RIDGING WEST AND
TROUGHING EAST PATTERN OVER THE GREATER NORTH AMERICAN DOMAIN. THIS
PATTERN WAS BEING KEPT IN PLACE BY OMEGA-STYLE UPPER BLOCKING OVER
THE NORTHERN PACIFIC BASIN. AT THE BEGINNING OF THE EXTENDED, UPPER
TROUGHING WILL BE IN PLACE OFF OF THE WEST COAST (THE EASTERN ANCHOR
OF THE UPPER BLOCK), WITH STRONG UPPER LEVEL RIDGING SITUATED OVER
THE SOUTHERN GREAT PLAINS. A PASSING UPPER LOW OVER THE CENTRAL
ONTARIO AND QUEBEC REGION WILL DEEPEN, AND HELP AMPLIFY UPPER
TROUGHING FROM THE EASTERN GREAT LAKES TO NORTHERN FLORIDA. THIS WILL
PLACE THE TENNESSEE VALLEY IN A WNW-ESE FLOW FROM THE LATE WEEK INTO
EARLY NEXT WEEK.
A NORTHWESTERLY UPPER LEVEL FLOW ACROSS THIS AREA, ESPECIALLY IF IT
IS DISTURBANCE LADEN, IS KNOWN FOR BRINGING SHOWERS AND THUNDERSTORMS
TO THE VALLEY. CONVECTION IN THESE REGIMES CAN BE ACCOMPANIED BY
STRONG WINDS. FOR THIS AREA, A FEW COMPLICATIONS TO THAT SIMPLISTIC
VIEW. FIRST, A COLD FRONT SHOULD BE SOUTH OF THE AREA BY LATE THU.
MOISTURE FROM TROPICAL STORM BERTHA SHOULD BE STREAMING BACK TO THE
NE, WITH SOME OF IT IMPACTING THE AREA FRI INTO SAT. ALONG WITH LOWER
LEVEL TROPICAL MOISTURE, SOME OF THE EXTENDED GUIDANCE WAS SUGGESTING
THAT UPPER LEVEL SUPPORT MOVING ACROSS THE AREA FROM LATE FRI INTO
SUN COULD BRING MORE THUNDERSTORMS TO THE AREA. IT IS WAY TOO EARLY
TO DISCERN IF THIS CONVECTION COULD BECOME MORE SIGNIFICANT, GIVEN
MUCH MODEL UNCERTAINTY THIS FAR OUT. WITH A MAIN SYNOPTIC FRONT TO
OUR SOUTH AND WITH SOME SHOWER/STORM CHANCES, DAILY HIGH/LOW
TEMPERATURES SHOULD TREND A BIT MILDER, WITH HIGHS FRI/SAT IN THE MID
80S TO AROUND 90. WARMER CONDITIONS LOOK RETURN FOR THE START OF THE
NEW WEEK, WITH HIGHS FROM THE UPPER 80S TO LOWER 90S SUN, AND LOW/MID
90S NEXT MON. LOWS THU NIGHT SHOULD RANGE IN THE MID/UPPER 60S, WITH
MAINLY LOWER 70S FOR THE FRI - SUN NIGHT PERIOD.
AVIATION
(06Z TAFS)
ISSUED AT 1224 AM CDT TUE JUL 21 2026
VFR CONDITIONS SHOULD CONTINUE A FEW MORE HOURS. HOWEVER, AROUND
08Z, WITH CLEAR SKIES AND LIGHT WINDS, EXPECT VSBYS TO BECOME MVFR
DUE TO PATCHY FOG DEVELOPMENT. SOME MODELS SHOW AN AXIS OF LOW
CLOUDS PUSHING NORTHWEST AND MAYBE OVER THE TERMINALS AROUND 9Z.
THIS COULD KEEP DENSE FOG FROM FORMING, BUT IT WILL DEPEND ON HOW
EXPANSIVE THIS LOW CLOUD DEVELOPMENT IS FROM WEST TO EAST. IF IT
IS A VERY THIN AXIS OF CLOUDS, THEN DENSE FOG STILL COULD DEVELOP.
LEFT DENSE FOG OUT OF THE TERMINALS FOR NOW, BUT MAY NEED TO BE
ADDED VIA AMENDMENTS.
HUN WATCHES/WARNINGS/ADVISORIES
AL...HEAT ADVISORY UNTIL 8 PM CDT THIS EVENING FOR ALZ001>009-016.
TN...HEAT ADVISORY UNTIL 8 PM CDT THIS EVENING FOR TNZ076-096-097.
NEAR TERM...RAD
SHORT TERM....RAD
LONG TERM....RSB
AVIATION...KTW
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