627
FXUS64 KHUN 240747
AFDHUN

Area Forecast Discussion
National Weather Service Huntsville AL
247 AM CDT Fri May 24 2024

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

.NEAR TERM...
(Today)
Issued at 247 AM CDT Fri May 24 2024

While the current radar is clear for the TN Valley, we are
monitoring a few areas of ongoing convection that will track
toward our area. The first is a convective complex to our west
that will steadily track eastward throughout the morning hours.
Additionally, a remnant outflow boundary draped from northern
Mississippi through central Alabama will be a focus for additional
shower/storm development this morning. The primary forcing for
lift will be a weak shortwave trough rippling through the zonal
flow aloft, which will provide extra synoptic scale support for
ascent.

For storm intensity, we will not be in a very favorable dynamic
environment with weak wind shear values this morning. As is
typical for this time of year, our thermodynamic profile becomes
more supportive with diurnal heating. Therefore, while some
stronger storms with wind gusts near 40 mph and small hail are on
the table this morning, we would expect the potential for severe
storms to peak in the late afternoon to evening hours. We will
need to monitor radar trends closely for the potential multiple
rounds of storms that will track over our area from the west.
Primary threats at peak intensity time will be hail, damaging wind
gusts, and a low chance for a tornado (best tornado probabilities
will be in the Midwest). With weak shear present, a low end
flooding threat comes to mind as weak corfidi vectors indicate the
potential for backbuilding, on top of the multiple rounds of
storms. For now, widespread 1-2" of rain are forecast but
localized totals up to 3-4" may cause some nuisance flooding in
low lying or poor drainage areas.

&&

.SHORT TERM...
(Tonight through Monday)
Issued at 247 AM CDT Fri May 24 2024

If spending time outdoors at all this Memorial Day Weekend, be
sure to know where you will go if there is a thunderstorm in your
area. Unfortunately, we will have multiple rounds of storms to
keep track of throughout the 3-day weekend.

For Saturday, confidence in any strong or severe storms is low,
but our main concern will be a weak zone of surface convergence
moving in from the northwest on the southern flank of a surface
high pressure system tonight. This will provide an area of focus
for storms throughout the day Saturday with medium chances
(40-60%) for the entire region. Timing remains a challenge based
on when storms form to our west and what path they take, as well
as how frequently they reinvigorate along a leading outflow
boundary. If you don`t have a storm form over your area, you will
likely be able to see one in the distance.

A fairly deep fetch of southerly flow in low levels will advect
in more Gulf moisture, as dew points surge into the low 70s on
Sunday. With high temperatures in the low 90s, please be mindful
of heat risks when spending time outdoors, particularly for
sensitive groups. Attention on Sunday turns to a shortwave trough
tracking through the Central Plains with an associated surface low
that will push through the Mid-Mississippi Valley. While storm
chances will be initially low on Sunday morning (10-30% chance),
those will increase overnight as a line of strong to severe storms
forms along a cold front. A recent trend has been for timing to
push back, so while this initially looked to be Sunday
evening/night, it now looks to be closer to midnight to early
morning on Monday (60-80% chance). While not necessarily as
favorable thermodynamically for severe weather, we will have a
good wind profile in place with a LLJ of 30-40 kts to support a
low end tornado threat. Over the next few days, this Sunday
night/Monday morning round will be the one to keep an eye on. The
most likely scenario is that the line of storms will race ahead of
the cold front, lose that stronger forcing to maintain its
severity, and then gradually weaken as it tracks across the area.

Due to lower confidence in timing, we have kept rain chances in
the forecast through Memorial Day on Monday. If the early morning
storms outpace the front, then depending on how much the
environment may recover on Monday, it is entirely feasible that
additional storms could form Monday afternoon with the true
frontal passage. It is not as likely at this time that any storms
that do develop would become severe.

&&

.LONG TERM...
(Monday night through Thursday)
Issued at 247 AM CDT Fri May 24 2024

A broader troughing pattern sets up Monday night for the eastern
CONUS and will persist through the remainder of next week. While
our next chance at storms is a lower end potential on Wednesday,
the pattern overall looks to be drier with temperatures closer to
daily average values in the low to mid 80s.

&&

.AVIATION...
(06Z TAFS)
Issued at 1151 PM CDT Thu May 23 2024

A few SHRA or perhaps a TSRA will be possible thru 9Z in the
vicinity of a subtle outflow boundary positioned north of the TN
River, but confidence in coverage is too low to include
precipitation in the TAFs initially. However, an approaching upper
air disturbance will likely begin to initiate additional
convection to our west around or shortly after 9Z, which should
spread eastward, warranting TEMPO groups for MVFR cig/vsby
reductions from 11-15Z/MSL and 12-16Z/HSV. AWWs for lightning and
brief strong wind gusts may be issued during this period, as well.
In the wake of morning precipitation, additional SHRA/TSRA will
be possible along a trailing outflow boundary late tomorrow aftn,
with a broader cluster of storms potentially spreading
southeastward thru at least the western portion of northern AL
tomorrow evening. Due to this, we have included PROB30 groups btwn
22-04Z, although timing will likely need to be adjusted as we
move forward in time. Prevailing conditions outside of convection
will remain VFR, with sfc winds from SSE-SSW at speeds of 5-10
kts.

&&

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

$$

NEAR TERM...30
SHORT TERM....30
LONG TERM....30
AVIATION...70