534
FXUS64 KHUN 160902
AFDHUN

Area Forecast Discussion
National Weather Service Huntsville AL
402 AM CDT Thu May 16 2024

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

.NEAR TERM...
(Today)
Issued at 402 AM CDT Thu May 16 2024

Upper ridging and surface high pressure will lead to a rain-free,
nice day today. In fact, other than a few upper level clouds
streaming over the region, it should be mostly sunny as well. This
will result in it being be a touch warmer, with highs reaching
the lower to mid 80s this afternoon. With light winds and dew
points rising into the lower 60s, it will feel like it`s in the
mid 80s out there today. Enjoy the day, because showers and storms
return to the forecast for Friday and into the weekend.

&&

.SHORT TERM...
(Tonight through Saturday Night)
Issued at 402 AM CDT Thu May 16 2024

Tonight begins a shift in the weather pattern that will continue
through Saturday, as the upper ridge gives way to an incoming
shortwave trough from the west, along with more subtle shortwaves
moving over the Deep South and up into the Tennessee Valley. Model
guidance has come into better agreement with the timing and
evolution of this trough through the region in recent runs as
well. A surface low pressure system is also expected to develop
and traverse central to southern Plains tonight, continuing east
over the Tennessee Valley by Saturday morning (our local area in
the warm sector), then move over the eastern seaboard Sunday
morning. Overall, low to medium chances (20-55%) of showers and
storms are forecast to begin late tonight and increase to high
(80-90%) on Friday. Medium to high chances (60-80%) then continue
Friday night through Saturday before tapering off Saturday evening
(10-30%).

The main questions with this forecast lie in the potential for
strong to severe storm development Friday into Friday night.
Guidance continues to suggest that an MCS will progress over the
Louisiana bootheel to southern Mississippi and southern Alabama
late tonight into early Friday. How this feature may modify the
environment farther north will be telling for strong to severe
storm potential later in the day. Will it cut off moisture
transport and resultant instability? Will an outflow from it help
initiate convection later in the afternoon? Some of this may not
be able to be answered until closer to the time with mesoscale
analyses. However, looking at model guidance, most side with the
scenario that instability will likely be cut off in the early
afternoon, with mainly showers and perhaps general thunderstorms
(sub- severe) the theme. The other question is whether the
atmosphere will be able to "recharge" for storms to blossom in the
late afternoon/evening as the aforementioned cold front moves
through. If it can, there will be ample instability (along with
shear and helicity) for storms to tap into and possibly become
strong to severe. Additionally, models indicate the presence an
850 mb jet moving over Louisiana Friday morning, then central
Mississippi in the early afternoon, and into Alabama in the late
afternoon/evening; however, there is disagreement if this will
make it into northern Alabama or stay south of us.

Overall, confidence in severe weather occurrence is low. But, if
storms do get going, then they could bring damaging winds, hail,
frequent lightning, and heavy downpours. The tornado threat is
non-zero but we have very low confidence in the occurrence of
tornadoes at this time. The Storm Prediction Center has outlooked
all of our northern Alabama and southern middle Tennessee counties
in a Marginal Risk (level 2/5) of severe weather Friday and
Friday night. Showers and storms will continue through the day on
Saturday, but are expected to be sub-severe. Model instability and
bulk shear values are sufficient for storm development, but not
extraordinary for severe weather.

Lastly, for temperatures, highs Friday will likely only reach the
mid to upper 70s due to the coverage of clouds and precipitation.
As shower/storm chances continue into Saturday, highs are
forecast to be a touch warmer, in the upper 70s to around 80
degrees. Lows will then generally remain in the lower to mid 60s
each night.

&&

.LONG TERM...
(Sunday through Wednesday)
Issued at 402 AM CDT Thu May 16 2024

A system that is expected to bring unsettled weather to close out
this week, by Sunday should be moving eastward over the Mid
Atlantic. Most of the showers activity should be east of the
region in the morning. But heating of residual moisture and
resultant instability could bring isolated to scattered (20-30%)
chance of showers and thunderstorms. This convection should it
occur should remain east of the Interstate 65 corridor, and in the
afternoon. Otherwise despite weak cold air advection, high
temperatures to start the week should warm into the mid 80s.
Shower activity should end Sun evening as high pressure building
in from the west becomes more of an influence on the sensible
weather. Low temperatures should cool into the lower 60s. The
start of the workweek/Monday should feature mostly sunny skies,
with highs rising into the upper 80s. Similar if not a tad warmer
on Tuesday with highs warming to around 90 in few places. Lows
Mon/Tue night should range in the mid/upper 60s.

Surface high pressure should build east of the Tennessee Valley
during Mon/Tue, returning a southerly flow over the area. Another
system forming over the northern Great Plains will head towards
the Great Lakes. A cold front trailing the parent low over
southern Canada will move across the area on Wednesday. Thus have
returned shower and thunderstorm chances to the Valley, beginning
late Tue night and continuing on Wed. With clouds and rain
chances, high temperatures should be in the mid 80s.

&&

.AVIATION...
(06Z TAFS)
Issued at 1153 PM CDT Wed May 15 2024

No changes to previous aviation forecast reasoning, as mostly
clear skies overnight will promote development of BR/FG as the
boundary layer remains moist and winds will be nearly calm with a
ridge of sfc high pressure nosing into our region from the north.
Although we have included a TEMPO group for MVFR vsby reductions
at both terminals btwn 9-13Z, fog may develop earlier than
indicated and could become locally dense (producing LIFR vsby)
within the timeframe of the TEMPO. VFR conds will return by 15Z
(if not sooner), with lgt/vrbl flow transitioning to a lgt SE wind
by mid-afternoon. Thick cirrostratus will overspread the region
tomorrow evening ahead of an MCS to our southwest, with SSE flow
gradually becoming more established as well.

&&

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

$$

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