Area Forecast Discussion
Issued by NWS Huntsville, AL

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000
FXUS64 KHUN 250808
AFDHUN

Area Forecast Discussion
National Weather Service Huntsville AL
308 AM CDT Mon Mar 25 2024

...New NEAR TERM, SHORT TERM, LONG TERM, AVIATION...

.NEAR TERM...
(Today)
Issued at 308 AM CDT Mon Mar 25 2024

An active period of weather is upon us as a dynamic storm system
will approach the region today, bringing strong, gusty winds and
dense cloud cover. Early this morning, a few light returns were
noted on radar from cloud bases around 12-15 kft and it`s possible
a few sprinkles may be felt from this activity during the predawn
hours. However, most of the day will be characterized as dry as
southeasterly winds will gradually veer to the south -- slowly
eroding away a wedge of dry air. This can be seen with PWATs
jumping from near 0.6" around daybreak to 1.0-1.2" by the late
afternoon.

Speaking of the winds, a 50-60 kt LLJ will push northward across
the area during the daytime hours. We`re already beginning to see
of the effects of this feature with winds gusting between 15-25
MPH in some of our observational sites already. After 12z -- and
especially by the afternoon, sustained winds will increase to
between 15-25 MPH, with gusts as high as 40-45 MPH. Given this
earlier onset of stronger gradient winds, we have bumped up the
start of the Wind Advisory to 12z this morning. These winds will
most definitely blow around unsecured items outdoors and
potentially knock down a few trees/tree limbs, causing power
outages. Very late in the day, very low (20%) PoPs were introduced
to far northwest Alabama. However, most locations will remain
devoid of rain with southerly winds helping to warm us in to the
mid 60s.

&&

.SHORT TERM...
(Tonight through Thursday)
Issued at 308 AM CDT Mon Mar 25 2024

The mid/upper low will pivot into the mid-Mississippi Valley this
evening and become negatively tilted overnight as another stronger
LLJ (60-70 kt) shifts eastward across the Tennessee and lower
Ohio Valleys. Thus, the threat for even stronger gradient winds
will exist this evening and overnight where sustained winds of
20-30 MPH with gusts to 50-55 MPH will be possible. Again, some
sporatic tree/power line damage cannot be ruled out with gusty
winds this strong which will likely persist through most of the
overnight period. This is addressed in the updated Wind Advisory
which will go through 12z Tuesday.

Meanwhile, a strong surface cold front will progress eastward
through the Mid South tonight, with a prefrontal trough pushing
eastward through the Tennessee Valley overnight. Strong
dynamics/forcing will generate some deep convection along/ahead of
this prefrontal trough -- with very strong shear values (0-6 km
shear of 70+ kts and 0-1 km shear of a staggering 40-50 kts!!).
The main caveat will be the utter lack of any real surface-based
instability of which CAMs and the Grand Ensemble keep displaced
well to our south and west across the ArkLaMiss (where the warm
sector will reside). Model soundings do indicate some meager
elevated instability values of 50-200 J/kg. With wind shear
values this strong, organized, elevated convection will be
present, likely in the form of a line of strong showers and storms
that will likely pass through the area roughly during a 03-09z
window. Though elevated, some of the stronger updrafts may tap
into the stronger winds aloft and create a few strong to
marginally severe storms capable of localized gusty/damaging
winds. For this reason, SPC has maintained a MRGL risk in the
western portion of our CWA -- though again we do think the
overall threat for severe weather is low -- and that gradient
(non-thunderstorm) winds pose the far greater hazard.

PWATs will also continue to increase ahead of the cold front and
into the 1.2" to 1.4" range during this timeframe (90th to 95th
percentile per BMX sounding climatology). This will create an
environment favorable for efficient rain-producing storms. The one
saving grace from any larger hydro/flooding concerns will be the
progressive nature of this convection as it pushes through the
area overnight. The latest ensemble and forecast guidance
continues to trend downward slightly with QPF amounts and for this
reason, WPC has lowered the ERO to MRGL for our area. Storm total
rainfall amounts will still fall within the 1" to 2" range, with
locally higher amounts of around 2.5". These rainfall values may
result in some rises on rivers, creeks, and streams and
potentially a localized flooding issue in a location where
rainfall amounts outperform.

The threat of strong, gradient winds will come to an end by 12z
Tuesday morning as the LLJ lifts NE into Tennessee and Kentucky.
Very high chances of rain overnight (80-100%) will drop to 40-80%
during the morning hours and 20-50% during the afternoon as the
true cold front finally pushes east and any additional convection
begins to taper off from west to east by the afternoon hours.
Southerly flow will help warm temperatures close to 70 degrees on
Tuesday, before winds shift to the NW late in the day and
temperatures drop off quickly Tuesday night -- eventually
settling into the low to mid 40s by early Wednesday morning. A
secondary trough will swing across the Deep South Wednesday and
Thursday, keeping this cooler air mass in place and highs in the
60s and lows in the upper 30s to lower 40s.

&&

.LONG TERM...
(Thursday night through Sunday)
Issued at 308 AM CDT Mon Mar 25 2024

A strong area of high pressure to the west will shift eastward
across the Tennessee Valley and Deep South Friday into the
upcoming Easter holiday weekend. The end result will be ample
sunshine and a pronounced warming trend as winds veer back to the
south. Dry conditions will also continue as the forecast will
remain devoid of any rain. Highs on Friday will return to the
upper 60s to lower 70s -- with mid/upper 70s forecast both
Saturday and Easter Sunday.

&&

.AVIATION...
(06Z TAFS)
Issued at 1059 PM CDT Sun Mar 24 2024

VFR conditions are expected at both terminals much of the TAF
period. Winds will be the big impact at the terminals though as
gradient winds increase after 25/06Z to around 20 knots with gusts
up to 30 knots possible. During the afternoon, expect winds to
increase to around 30 knots with gusts to around 40 knots (mainly
between 25/20Z and 26/00Z). CIGS will lower, but likely not below
3000 feet until between 00Z and 03Z. Only, -SHRA were included at
this time after 0z to 03Z timeframe.


&&

.HUN WATCHES/WARNINGS/ADVISORIES...
AL...Wind Advisory from 7 AM this morning to 7 AM CDT Tuesday for
     ALZ001>010-016.

TN...Wind Advisory from 7 AM this morning to 7 AM CDT Tuesday for
     TNZ076-096-097.

&&

$$

NEAR TERM...AMP.24
SHORT TERM....AMP.24
LONG TERM....AMP.24
AVIATION...KTW


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