Flash Flood Warning 20, NWS Birmingham, AL

Area Forecast Discussion
National Weather Service Birmingham AL
710 AM CDT Sat Jun 20 2026

...New AVIATION...

.KEY MESSAGES...
Issued at 705 AM CDT SAT JUN 20 2026

- Flooding: A Flood Watch is in effect for much of Central Alabama
  through this evening due to a high chance for additional heavy
  rains falling on already saturated soils. Flash flooding will be
  possible along and south of the I-22 corridor, stretching
  eastward to the Birmingham Metro area and the I-20 corridor.

- Severe: There is a Marginal Risk (Level 1 of 5) for severe
  storms across much of Central Alabama Monday afternoon and
  evening. Damaging winds are currently the main threat.

- Heat: Heat index readings approaching 100 degrees are forecast
  beginning Monday and Tuesday.

&&

.DISCUSSION...
(Today through Friday)
Issued at 457 AM CDT SAT JUN 20 2026

How about a good ole fashioned forecast update during the
overnight shift? It was certainly needed tonight, as the short-
term forecast has trended much more active over the past
12 hours. The latest CAMs hot off the press this morning are in
pretty good agreement with the development of widespread showers
and storms over much of the CWA along a stalled frontal boundary
currently draped across Central Mississippi and Alabama.  Current
surface analysis indicates that the I-20 corridor is currently
"wedged" in between higher pressure along the central Gulf Coast
and Tennessee Valley region north of the stalled front. A mid-
level shortwave impulse moving in from the west will provide
plenty of synoptic lift aloft, combined with convergence at 700mb
and a saturated profile from 1000-500mb.  One or more MCVs in the
area could also trigger additional development. PWATs of 2+
inches are also expected to advect eastward into the CWA as 925-
850mb moisture transport brings in tropical moisture from the
southwest.

As storms develop and slowly move east-southeastward this morning
through this evening, the threat for flash flooding will increase
as storms are expected to not only move across similar areas, but
also where soils remain saturated from recent rounds of heavy
rain. Following coordination with WPC overnight, we've decided to
go ahead and issue another Flood Watch for most of the CWA
through this evening. Any torrential downpours that occur with
rain rates of 2-3 inches per hour will cause flooding to occur at
a much faster pace due to the water-logged soil conditions. We'll
have to watch the hydro desk very closely throughout the day
today.  CAMs have indicated this morning that heavy rains may
develop along and south of a line stretching from the I-
22 corridor to the Birmingham Metro and eastward to the I-
20 corridor.  If some of the CAMs verify, we'll need to watch for
a flash flood/urban flood potential within some of the higher
population centers, such as Tuscaloosa, Jasper, and Birmingham
through the first half of the day today.  Based on the storm
development trends we observe today, we can determine if the
watch will need to be extended further into the evening for the
southern half of the CWA.  The northern counties within the watch
could be trimmed back a little earlier in the day as drier air
aloft filters in as 500mb flow becomes northwesterly this
afternoon.

56/GDG

&&

.AVIATION...
(12Z TAFS)
Issued at 705 AM CDT SAT JUN 20 2026

An unexpected break in the IFR ceilings occurred for many
terminals this morning ahead of the approaching SHRA/TSRA in
Mississippi. As convective development occurs later this morning,
ceilings are forecast to drop once again with prevailing SHRA
which will limit visibility at times as coverage increases. KTCL
will be affected first, followed by KBHM and KEET between 15z and
18z. TEMPO TSRA has been added into the forecast as well with
high confidence of storm coverage near the terminals from 17z to
21z. Interests should expect frequent amendments and potentially
an addition of prevailing TSRA for terminals through this
afternoon. TEMPO TSRA was also added in for KAUO and KMGM for
later this afternoon, but forecast confidence is a little lower
in terms of timing and overall storm coverage. Following
TSRA/SHRA ending this evening, VFR conditions can be expected
with the potential for lower ceilings returning once again. Winds
will remain light and variable outside of thunderstorms.

Note: Metars from AUO are coming through but observations are
missing data. Therefore, AMD NOT SKED has been added for this
set.

56/GDG

&&

.FIRE WEATHER...

High rain chances continue as we will remain in a wet pattern
through early next week. Ample moisture in place will keep MinRH
values above 50% through the entire forecast period. Elevated
fire weather concerns are not expected at this time.

&&

.PRELIMINARY POINT TEMPS/POPS...
Gadsden     82  67  87  73 /  40  10  50  50
Anniston    82  68  86  73 /  60  10  50  40
Birmingham  81  69  87  74 /  80  10  60  30
Tuscaloosa  82  71  86  75 /  90  10  70  20
Calera      83  69  89  73 /  90  20  60  20
Auburn      82  69  86  73 /  80  20  50  20
Montgomery  82  70  86  73 /  90  20  60  10
Troy        83  70  86  73 /  90  20  60  10

&&

.BMX WATCHES/WARNINGS/ADVISORIES...
Flood Watch until 7 PM CDT this evening for the following
counties: Autauga-Barbour-Bibb-Bullock-Chambers-Chilton-Clay-
Coosa-Dallas-Elmore-Fayette-Greene-Hale-Jefferson-Lamar-Lee-
Lowndes-Macon-Marengo-Montgomery-Perry-Pickens-Pike-Randolph-
Russell-Shelby-St. Clair-Sumter-Talladega-Tallapoosa-Tuscaloosa-
Walker.

&&

DISCUSSION...56/GDG
AVIATION...56/GDG