373
FXUS64 KHUN 081450
AFDHUN

Area Forecast Discussion
National Weather Service Huntsville AL
950 AM CDT Wed May 8 2024

...New NEAR TERM...

.NEAR TERM...
(Rest of Today)
Issued at 950 AM CDT Wed May 8 2024

Some light rain showers have been observed over the local area
this morning, as strong WAA continues over the region south of a
warm front. A cluster of strong thunderstorms can be seen moving
east through the I-40 corridor east of Nashville. This will be
important to watch throughout the day as we will remain in a warm
and moderately unstable environment. Though the better synoptic
forcing and main round of strong/severe thunderstorms is not
expected until late this evening/overnight, will keep a close eye
our for mesoscale boundaries that could provide enough lift to
generate storms this afternoon. Given a look at model soundings,
any storms that are able to form this afternoon will be in an
environment conducive for all forms of severe weather given a
likely supercell storm mode. Expect cloud cover to thin late this
morning, as already seen over NW AL, and will allow sfc temps to
rise into the mid to upper 80s. Given recent satellite trends, did
raise highs slightly during the morning update as well as tweaked
sky cover and PoPs to better match current trends. Be sure to keep
checking in for updates today as the afternoon round of storms
remains highly conditional but likely impactful if storms are able
to form.

&&

.SHORT TERM...
(Tonight through Friday night)
Issued at 437 AM CDT Wed May 8 2024

The forecast for tonight remains rather complicated, largely due
to the weak nature of deep-layer forcing for ascent across our
region and fact that thunderstorms will be tied to processes
occurring well to our northwest. However, at this point, the most
likely scenario seems to be that the risk for severe thunderstorms
across our CWFA may increase as early as the 0-3Z timeframe,
either from isolated cells that develop to our southwest late this
afternoon and spread northeastward, or with development of new
storms along outflow from widespread convection to our north that
may drift southwestward into southern TN/northeast AL. A separate
MCS may also evolve this evening out of convection that develops
late this afternoon along the cyclones cold front (extending from
the low southwestward into north central TX). Precisely where this
system will develop and track is still uncertain, but present
indications are that it would not arrive in our forecast area
until the 6-9Z timeframe at the earliest (and perhaps as much as
3-6 hours later than this). The combination of 40-50 knot WSW flow
aloft and steep mid-level lapse rates atop a moist boundary layer
(featuring dewpoints in the u60s-l70s) will support a risk for
large hail and damaging winds, with a modest SW low-level jet of
25-35 knots providing sufficient shear in the 0-1km layer for a
lower-end risk for tornadoes.

Several CAMs suggest that convective outflow will eventually
outrun the MCS as we move forward in time, with extensive trailing
stratiform rain and embedded thunderstorms expected to gradually
spread southeastward and out of the region by 18Z Thursday. The
actual cold front should shift southeastward late Thursday
afternoon and exit the forecast area during the evening hours, as
another broad complex of thunderstorms tracks eastward along the
central Gulf Coast. Although redevelopment of showers and storms
along the cold front appears unlikely in our region, we have
indicated a low-medium chance POP on Thursday night to account for
some uncertainty regarding the path of the MCS to our south and
potential for the northern edge of the stratiform rain shield to
graze our region.

In the wake of any lingering morning precipitation on Friday, dry
conditions are currently predicted on Friday and Friday night.
However, with a longwave trough expected to cross the region on
Friday and a trailing vort max digging southeastward into the
region Friday night, a fair amount of mid-level cloud cover is
anticipated (and perhaps even a few very light showers). These two
periods will mark the coolest of the forecast, with highs in the
u60s-m70s Friday and lows in the u40s-l50s Friday night.

&&

.LONG TERM...
(Saturday through Tuesday)
Issued at 437 AM CDT Wed May 8 2024

A generally dry weather pattern will continue across the region
this weekend. However, a clipper system diving southeastward into
the western Great Lakes will send a reinforcing cold front through
the region on Saturday, perhaps bringing a few light showers to
locations north of the TN River. Chances for rain will begin to
slowly return to the region as early as Monday, which is when a
series of lower-latitude troughs may initiate the development of
one or more areas of low pressure across the western Gulf of
Mexico that would shift northeastward early next week. Due to
indications of a modifying low-level airmass across the TN Valley,
instability will gradually increase as we move forward to
Tuesday, with a low chance for thunderstorms apparent as well.

&&

.AVIATION...
(12Z TAFS)
Issued at 645 AM CDT Wed May 8 2024

Overall, there have been no significant changes to previous
aviation forecast reasoning, as a low stratus layer will continue
to provide MVFR cigs arnd 1500 ft AGL thru 15-16Z. As the low
stratus layer disperses later this morning, a rapidly
destabilizing airmass will support the development of sct-bkn Cu,
with a few warm sector TSRA expected to develop to our SW late
this aftn, potentially impacting the terminals in the 23-05Z
timeframe. Probabilities for more a more widespread coverage of
storms will increase with time as we approach the end of the TAF
period, but confidence is not high enough to introduce anything
more than an additional PROB30 group attm. Prevailing sfc flow
will remain from the SSW, with sustained speeds of 5-10 knots (and
gusts of 15-20 knots this aftn).

&&

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

$$

NEAR TERM...25
SHORT TERM....70
LONG TERM....70
AVIATION...70