Flash Flood Warning 38, NWS Huntsville, AL

Area Forecast Discussion
National Weather Service Huntsville AL
1022 AM CDT Wed Aug 10 2022

...New NEAR TERM...

.NEAR TERM...
(Rest of Today)
Issued at 1022 AM CDT Wed Aug 10 2022

Showers and thunderstorms have spread across northern Alabama and
southern Middle Tennessee this morning, generally along a
convergence axis that lines up west to east across our entire
area, except Cullman County which is just south. With PWAT values
generally around 2.0-2.1 inches, high rainfall rates and slow
storm motion has led to accumulations of 2-4 inches of rainfall in
some areas, causing flash flooding. In general today, due to the
widespread rainfall, not expecting any severe thunderstorms due
to limited instability, but can't rule out a stronger storm
producing gusty winds this afternoon if we get any breaks in the
clouds.

High temperatures are currently forecast to stay down in
the low-to-mid 80s this afternoon. Again, if cloud cover and rain
remain fairly solid through the day this may be on the high end,
but breaks could get some areas up into the upper 80s.

&&

.SHORT TERM...
(Tonight through Saturday)
Issued at 154 AM CDT Wed Aug 10 2022

The front will begin to make a southeastern push later tonight as
an upper level trough passes to the north across the Great Lakes.
Expect a nocturnal decrease in showers/storms but with the front
just to the north and the elevated PW values, will carry at least
some mention of showers/storms throughout the overnight period. If
the coverage of showers/storms is rather sparse overnight, there
could be some patchy fog. Lows tonight will be in the low 70s for
most areas.

Thursday will be the last day that features elevated PoPs in the
forecast. The cold front will continue to slowly slide
southeastward into the forecast area. Moisture remains elevated
with PW near to just above 2 inches. Once again. lapse rates will
be weak in the saturated atmosphere and do not expect any severe
storms but cannot rule out a stronger storm or two with gusty
winds. Localized flash flooding will once again be a threat with
another day of heavy rainfall. Models differ a bit on the timing
of the front and some of the faster solutions indicate drier air
moving in before the end of the day from the northwest. Ridging
aloft will build in from the west late in the day as well and
could lead to an end of the precipitation chances. Highs on
Thursday will be on the cooler side with the widespread cloud
cover and precipitation throughout much of the day. Highs will
climb into the mid to upper 80s.

The front will push to the south of the area overnight Thursday
night with rain chances ending from northwest to southeast.
Dewpoints will remain elevated overnight. Do not expect the lower
surface dewpoints will arrive until later in the day on Friday.
Lows will be slightly cooler on Friday morning down in the mid to
upper 60s for most locations.

It seems as though the dewpoints have been above 68 degrees or so
for quite some time. This will finally change on Friday as much
drier air advects in from the north. PW values will plummet down
into the 0.75-1.00 inch range. These values are down around the
5th percentile for mid-August. Therefore, expect sunny skies
Friday and lasting throughout the weekend. The dry atmosphere
coupled with clear skies and light winds will lead to lows on
Saturday morning in the low to mid 60s for most locations. There
may be a few upper 50s in a few locations across northeast Alabama
and southern Middle Tennessee. Dewpoints will remain comfortable
on Saturday in the low 60s with high temperatures climbing into
the mid to upper 80s.

&&

.LONG TERM...
(Saturday night through Tuesday)
Issued at 154 AM CDT Wed Aug 10 2022

Another dry day is forecast on Sunday with temperatures starting
the day in the mid to upper 60s. Mostly sunny skies are forecast
as the front remains to the south of the area. Highs will be a bit
warmer as temperatures begin to moderate some. Highs on Sunday
will climb into the upper 80s to low 90s.

The upper level pattern throughout the long-term forecast period
will features a closed low to the north and east across New
England with a ridge across the Rocky Mountains and Great Plains.
This will put the forecast area in northwesterly flow aloft.
Models differ on how active the pattern will be during this
timeframe. There does appear to be at least a couple of
northwesterly shortwave troughs that could bring some chances for
showers/storms into the forecast area. Low chances for afternoon
showers/storms return to the forecast on Monday and Tuesday with
forecast highs and lows near climatological norms.

&&

.AVIATION...
(12Z TAFS)
Issued at 608 AM CDT Wed Aug 10 2022

VFR conditions currently across the terminals. Showers and storms
will become more widespread throughout the day with VCTS in both
terminals starting at 18z. Visibilities could drop down to MVFR to
IFR briefly in a heavier downpours but not enough confidence to
include this in the TAFs. VCTS ends in the TAFs at 01z but there
could still be a few lingering showers/storms during the overnight
period. Low level convergence increases late in the TAF cycle as a
front approaches from the northwest. Due to this, MVFR ceilings
are forecast to develop after 09z.

&&

.HUN WATCHES/WARNINGS/ADVISORIES...
AL...None.
TN...None.
&&

NEAR TERM...McCoy
SHORT TERM....MA
LONG TERM....MA
AVIATION...MA

Hazardous Weather Outlook
National Weather Service Huntsville AL
213 AM CDT Wed Aug 10 2022

ALZ001>010-016-TNZ076-096-097-110715-
Lauderdale-Colbert-Franklin AL-Lawrence-Limestone-Madison-Morgan-
Marshall-Jackson-DeKalb-Cullman-Moore-Lincoln-Franklin TN-
213 AM CDT Wed Aug 10 2022

This Hazardous Weather Outlook is for north central Alabama,
northeast Alabama, northwest Alabama and southern middle Tennessee.

.DAY ONE...Today and tonight.

Numerous to widespread thunderstorms are forecast today. Due to the
slow-moving nature of the thunderstorms, locally heavy rainfall will
be the primary risk. A few stronger storms could produce wind gusts
to 50 mph and frequent lightning.

.DAYS TWO THROUGH SEVEN...Thursday through Tuesday.

Numerous to widespread thunderstorms are forecast again on Thursday,
with storm coverage highest during the afternoon and early evening
hours. Due to the slow-moving nature of the thunderstorms, locally
heavy rainfall will be the primary risk. A few stronger storms could
produce wind gusts to 50 mph and frequent lightning.

Isolated storms are also forecast on Monday and Tuesday afternoons.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is not expected at this time.