Decatur, Alabama 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

536
FXUS64 KHUN 261142
AFDHUN

Area Forecast Discussion
National Weather Service Huntsville AL
642 AM CDT Tue May 26 2026

...New AVIATION...

.KEY MESSAGES...
Updated at 254 AM CDT Tue May 26 2026

 - A Flood Watch for Flash Flooding is in effect through 10 PM
   Tuesday for Cullman, Morgan, Madison, Jackson, Marshall and
   Dekalb counties.

 - Medium to high chances for showers and thunderstorms continue
   across the Tennessee Valley into the weekend.

&&

.NEAR TERM...
(Today)
Issued at 254 AM CDT Tue May 26 2026

Showers continue to develop and lift northward across the TN
Valley at this hour. This is due to a vort max moving through the
eastern flow of the anchored upper-level low in the ArkLaTex and
the tropical like airmass we remain in. The associated sfc low
remains in the Lower MS Valley with a stationary front draped from
there on up into the OH Valley. Have not seen any lightning come
from this batch of showers, but have seen heavy downpours create
visibility reductions.

The Flood Watch for Flash Flooding remains in effect for Cullman,
Morgan, Madison, Jackson, Marshall and Dekalb counties until 10 pm
tonight. Most of the forecast area has received over an inch of
rainfall over the past 48 hours, with an axis of 3-4" that
stretches from Jackson, SE Madison, western Marshall and a large
portion of Cullman Co...and that`s just the past 48 hours, not
even an event total. As you can imagine, locations in the Flood
Watch have a lower Flash Flood Guidance with an hourly value of
1-1.5" compared to ~1.75-2" elsewhere. Will have showers with
some thunderstorms once again today. Will start off with low
chances this morning and increasing through the day, with the the
greatest coverage found in the afternoon hours. PoPs this
afternoon will range from the low chances of 20-40% west of I-65,
to 50-80% east of I-65. Southerly winds will gust towards 15 mph
this afternoon and highs will only reach the upper 70s to lower
80s.

Remember: if you see water over the roadway or walkway, Turn
Around, Don`t Drown.

&&

.SHORT TERM...
(Tuesday night through Thursday)
Issued at 1120 PM CDT Mon May 25 2026

The forecast should take on more of a diurnal trend (this one with
higher rain chances afternoon/evening) as we go into through the
midweek. Another muggy night is expected Tuesday night, with lows
in the mid 60s. PW moisture of 1.6" to 1.7" is expected Wednesday,
bringing more potentially heavy downpours. With more clouds and
decent rain chances of 60-80%, high temperatures should range in
the low/mid 80s. Lows will cool into the mid/upper 60s. Similar
conditions are forecast on Thursday. A cold front located to our
north, will approach the forecast area later in the day. Depending
upon timing, it could bring higher rain chances as well as
stronger storms.

The Weather Prediction Center has most, if not all of the area in
a Marginal Risk for excessive rainfall this week. Thus depending
upon when and where rainfall occurs, if it is heavy and falls on
an area that is very wet to saturated from recent rains, runoff
will occur and bring risks of flash flooding and flooding across
the Tennessee Valley through Thursday. Thunderstorm chances will
remain in the forecast as well, except "general" intensity
convection is anticipated with the usual gusty outflow winds and
heavy downpours. Storms in high PW regimes can become electrically
active as well.

&&

.LONG TERM...
(Thursday night through Monday)
Issued at 1120 PM CDT Mon May 25 2026

Most guidance shows the surface front pushing south of the area by
Thursday evening. Cloud cover should linger though behind the front
over the area. Not much appreciable cold air advection or drier air
shown right behind the front. This combination should keep overnight
lows on the warm side in the lower to mid 60s. This should also
provide a brief break from rainfall activity.

Most guidance moves the front northward around daybreak on Friday
into northwestern Alabama and possibly some of our southeastern
counties in AL. Forcing is not very strong, but does move back over
the area. Instability between 1000 and 1600 J/KG (some guidance a bit
more) does develop by the afternoon hours. Shear though is very weak
(~10 to 15 knots). PWATS remain high between 1.6 to 1.8 inches. So a
very saturated atmospheric column will not take much forcing to
produce heavy rainfall rates. A continue threat for a period of rain
and thunderstorms developing during the afternoon and early evening
is expected. A flooding risk will likely extend into Friday.

Much deeper and stronger forcing seems to develop in many models
Saturday overnight as the main upper level trough axis moves east
aloft. This could produce a concentration of heavier rainfall and
some storms more so over Georgia and maybe extending west into NE
Alabama. A risk for some flash flooding will likely continue on
Friday afternoon into Friday night.

Models diverge on how amplified the upper level trough axis is Friday
night into Saturday and into the weekend, which will have a big
impact on whether the front shifts south of the area or not.

Model converge a bit more on stronger forcing and shear developing
over the area on Monday. Shear is better with this system and
instability is not bad. There may be some strong to severe
thunderstorm threat with that system, but this is too far out in
the extended to have much confidence with it.

&&

.AVIATION...
(12Z TAFS)
Issued at 642 AM CDT Tue May 26 2026

Showers and a few thunderstorms are expected again today with the
greatest coverage during the afternoon hours. Terminals will
generally be have CIGS in MVFR, however heavy rainfall can cause
brief IFR CIGS and trends are suggesting CIGS could fall to IFR
towards the end of the TAF period. Did not have the confidence to
lower them that far yet for this TAF issuance.

&&

.HUN WATCHES/WARNINGS/ADVISORIES...
AL...Flood Watch through this evening for ALZ006>010-016.

TN...None.
&&

$$

NEAR TERM...JMS
SHORT TERM....RSB
LONG TERM....KTW
AVIATION...JMS