003
FXUS64 KHUN 261835
AFDHUN

Area Forecast Discussion
National Weather Service Huntsville AL
135 PM CDT Sun Jul 26 2026

...New NEAR TERM...

.KEY MESSAGES...
Updated at 135 PM CDT Sun Jul 26 2026

 - Heat Advisory in Effect for areas along and west of I-65
   through Tuesday 7 PM.

 - There is a low chance for strong to severe storms early Monday
   morning and again Tuesday afternoon.

 - A cold front (preceded by thunderstorms) will bring a slightly
   cooler/drier airmass to the region for the end of the work
   week. Rain chances will increase once again early next weekend.

&&

.NEAR TERM...
(Tonight)
Issued at 135 PM CDT Sun Jul 26 2026

Morning low level cloud cover has cleared out leaving just some
high clouds overhead with plenty of sunshine filtering through.
As of 1pm, temperatures have climbed into the upper 80s and are
forecast to continue to rise into the lower 90s later this
afternoon. Of greatest concern is that the dewpoints have not
mixed out at all and are sitting in the upper 70s to 80F. This has
resulted in dangerous heat conditions. While we have not reached
heat advisory criteria as of yet, with a few more hours of warming
left it is expected heat indices will climb above 105 degrees for
areas along and west of I-65. Therefore, a heat advisory has been
issued and will continue through 7 pm Tuesday evening. The rest
of the forecast remains on track with more details about the early
morning storms in the following paragraph.

Previous Discussion:
Our attention tonight is on an upstream MCS forming to our north
and riding southward along the instability gradient into our local
forecast area. Timing and intensity of this system as it reaches
southern middle TN is quite uncertain. However, several CAMs show
this feature arriving in the early morning hours Monday (4-8 am)
with the most likely area being locations east of I-65. Forecast
soundings show between 1000-2000 J/kg of MLCAPE with deep layer
shear between 20-30 kts. If storms can remain sfc based the main
threats would be damaging wind gusts and heavy rainfall.

&&

.SHORT TERM...
(Monday through Tuesday)
Issued at 1108 AM CDT Sun Jul 26 2026

There is the potential for an ongoing MCS to be present at the
start of the short term period Monday morning. As it continues to
push south, it will likely be on a weakening trend before it
gradually dissipates by the late morning. The impacts of the
cloud cover and rain associated with this system will likely
impact the potential for dangerous heat later Monday afternoon.

Through the first part of next week, the upper level pattern
remains unchanged with a large ridge over the central US and a
trough across the Northeast. The morning CAM suite indicates that
with daytime heating, additional showers and storms may redevelop
along residual outflow boundaries from the morning MCS. Coverage
of these storms during the afternoon appear too low to really
impact the heat potential during the peak heating hours. Afternoon
highs will warm into the lower 90s east and mid 90s west with
heat index values in low 100s in NE AL and between 103F-107F
further west. On Tuesday, the upper ridge shifts a bit further
east. This will warm afternoon temperatures up a few degrees with
afternoon highs reaching the mid to upper 90s. This will bring
afternoon heat index values between 105-110 degrees with a few
degrees cooler in NE AL. Given these conditions, a Heat Advisory
has been issued for our counties along and west of I-65 from 10 am
Monday through Tuesday evening. Additional counties may be added,
especially on Tuesday if forecast confidence increases.

&&

.LONG TERM...
(Tuesday night through Saturday)
Issued at 1100 PM CDT Sat Jul 25 2026

Extended range model data suggests that a developing surface low
will track eastward across the northern Mid-Atlantic states on
Tuesday night/Wednesday, in conjunction with an amplifying longwave
trough across the eastern CONUS. A cold front attached to the low
appears likely to drop southward through the TN Valley during this
timeframe, although details regarding specific timing are unclear at
this point. A warm/moist airmass is expected to be in place ahead of
the front, with steep low/mid-level lapse rates and CAPE to support a
couple of rounds of thunderstorms (perhaps an MCS Tuesday night
followed by additional convection more directly forced by the cold
front Wednesday). Furthermore, deep-layer NW flow of 20-30 knots will
exist within a contracted height gradient between the trough to our
east and a strong mid-level high over the southwestern CONUS, and
this could support a risk for damaging winds given the favorable
thermodynamic environment.

In the wake of the front, light-moderate northerly winds will advect
a cooler/drier continental airmass into the region, with dewpoints
briefly falling into the 60s an PWAT values falling to around or
slightly below 1" from Wednesday night-Thursday night (and perhaps
into Friday as well). By the end of the forecast period, deep-layer
SSW flow will return to the region as an amplifying shortwave trough
(traveling around the periphery of the ridge to our west) digs
southeastward into the Mid-MS/Lower-OH Valley region and a surface
low shifts eastward from the Red River Valley into the Arklamiss
vicinity. Rich moisture will return to the region as this occurs,
with an increase in the coverage of showers/thunderstorms expected
beginning late Friday night and continuing through Saturday.

&&

.AVIATION...
(18Z TAFS)
Issued at 1126 AM CDT Sun Jul 26 2026

MVFR clouds continue to linger at HSV, but should lift early this
afternoon. Then VFR conditions continue through the rest of the
period. The one exception is Monday morning where an MCS is
expected to bring showers and thunderstorms to the terminals. For
now left thunderstorms within a prob 30 group as there is a lot of
uncertainty in timing and location of this system.

&&

.HUN WATCHES/WARNINGS/ADVISORIES...
AL...Heat Advisory until 7 PM CDT Tuesday for ALZ001>007-016.

TN...Heat Advisory until 7 PM CDT Tuesday for TNZ076-096.

&&

$$

NEAR TERM...GH
SHORT TERM....GH
LONG TERM....70
AVIATION...GH