438
FXUS64 KHUN 131835
AFDHUN

Area Forecast Discussion
National Weather Service Huntsville AL
135 PM CDT Mon May 13 2024

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

.NEAR TERM...
(Remainder of today and tonight)
Issued at 135 PM CDT Mon May 13 2024

A large MCS will continue to progress southeastward across
portions of the FL Panhandle/southern GA and the northeastern Gulf
of Mexico this afternoon, with broad scale subsidence along the
northwestern periphery of this feature likely to prevent
redevelopment of showers and thunderstorms across the local CWFA.
Thus, we have reduced near term POPs (through 0Z) into the low
chance range. Otherwise, an abundant coverage of low stratus
clouds is expected in the deep-layer warm/moist advection regime
to the east of a mid-level shortwave trough across the southern
Plains and related surface cyclone drifting eastward across
eastern KS. In spite of SSE winds in the 10-15 MPH range
(occasionally gusting to 15-20 MPH), highs will be impacted by the
presence of cloud, and should range from the u60s(E) to l70s(W).

Model guidance from the 12Z CAMs suggests that conditions will
remain dry across the forecast area this evening, before chances
for showers and thunderstorms begin to increase once again during
the early morning hours Tuesday. This activity may be initiated by
a northeastward-surging outflow boundary originating from a
second MCS that will develop along the northwestern Gulf Coast
later this afternoon and take a similar path to the east-southeast
(through the northern Gulf of Mexico) overnight. Although
elevated CAPE will increase this evening due to steepening mid-
level lapse rates and gradual cooling aloft to the east of the
approaching shortwave trough, forecast soundings depict a low-
level inversion and updrafts may be slightly elevated. Thus,
lightning, locally heavy rainfall and perhaps some small
hail/brief wind gusts of 30-40 MPH will be the main storm impacts.
Overnight lows will generally be in the l-m 60s.

&&

.SHORT TERM...
(Tuesday through Thursday)
Issued at 135 PM CDT Mon May 13 2024

A fairly widespread coverage of showers and elevated
thunderstorms will likely be in progress across the region around
12Z Tuesday, but should progress northeastward and out of the
region by mid- morning. Subsequent breaks in the early morning
stratus layer will allow for modest destabilization to occur late
tomorrow morning, with additional (but more scattered)
thunderstorm activity expected to develop to the west of our
region (across western TN/northern MS) by 16-18Z. This activity
should spread eastward through the TN Valley tomorrow afternoon,
and will likely represent our greatest risk for strong-severe
thunderstorms (warranting a Marginal Risk from SPC). The
combination of mid-level WSW winds in the 35-45 knot range and
MLCAPE perhaps as high as 1500-2000 J/kg in portions of the
forecast area will favor organized convection, which may initially
evolve as multicell clusters before growing into a broken line.
Large hail/locally damaging winds and frequent lighting will be
the main threats with this activity.

Present indications are that afternoon convection will gradually
weaken and spread eastward (out of the forecast area) early
Tuesday evening, but with additional showers possible ahead of a
surface trough (extending southward into our region from a low
tracking through the OH Valley), we will maintain a low-medium
chance POP region-wide through 6Z. A third and final round of
showers (and perhaps a few storms) will likely occur on Wednesday
with the passage of a weak cold front, but with a mid-level ridge
likely to be crossing the region in the wake of the shortwave
trough (noted above), storm coverage and intensity will be lower
(compared to Tuesday). Clearing skies and calm winds are expected
on Wednesday night as a narrow ridge of surface high pressure
noses into the region from the north, and this may support the
development of fog early Thursday morning as temps fall into the
u50s-l60s.

&&

.LONG TERM...
(Thursday night through Monday)
Issued at 342 AM CDT Mon May 13 2024

After brief upper ridging and surface high pressure that will
keep rain out of the forecast on Thursday will come what seems
like a "rinse and repeat" storm system (similar to the one
discussed above) for Friday and into Saturday. Upper ridging will
be pushed east as a trough makes its way over the Mississippi
Valley through late week. At the same time, a surface low pressure
system is shown to develop over southwestern Texas around midweek
and then traverse to the northeast towards the ArkLaTex region by
early Friday. Anticipating this system to continue its
northeastward trajectory that will take it over northern Virginia,
Delaware, and Maryland by Saturday morning. Chances of showers
and storms are forecast to increase overnight into Friday morning.
Unsettled weather will then likely persist through the weekend,
with the highest chances (60-70%) of showers and storms
anticipated Friday afternoon. While enough instability and shear
will be present for thunderstorm development Friday afternoon and
evening, the better upper dynamics and thermodynamics once again
look to be to our south (much like the storm system in the
near/short term). Overall, at this time, confidence in any severe
weather is low because of this. However, we will continue to
monitor this system in case the trajectory of the low tracks
northward (increasing the severe potential). Highs will generally
top out in the lower to mid 80s each day except for Friday (upper
70s) due to the increased coverage of showers and storms. Lows
will remain in the lower to mid 60s through the weekend.

&&

.AVIATION...
(18Z TAFS)
Issued at 1223 PM CDT Mon May 13 2024

MVFR conditions are forecast to continue this afternoon through
tonight as lowered ceilings continue. Tuesday morning into Tuesday
afternoon, rain showers/storms will allow conditions to sink to
IFR at times due to lowered ceilings and visibilities. In addition
to this, AWWs may be issued during the late morning hours to
account for lightning development.

&&

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

&&

$$

NEAR TERM...70/DD
SHORT TERM...70/DD
LONG TERM....26
AVIATION...HC