Tornado in Florida, February 11, 2025

Area Forecast Discussion
National Weather Service Mobile AL
322 PM CST Tue Feb 11 2025

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

.NEAR TERM...
(Now through Wednesday Night)
Issued at 322 PM CST Tue Feb 11 2025

The next 36 hours continue to look on the active side as the chance
for strong to severe storms remains possible Wednesday into
Wednesday night. A HIGH risk of rip currents will also begin
Wednesday and persist through the week.

Synopsis...Deep layer moisture continues to surge northward across
our area as deep southwesterly flow aloft overspreads the region
from west to east. This is all in response to a rather broad
longwave upper trough digging into the southwestern US. Several
shortwaves are expected to progress through the flow during the
period with the strongest ones pushing through Wednesday into
Wednesday night. At the surface, a warm front continues to advance
northward across the area this afternoon, likely stalling somewhere
over the interior portions of the forecast area by late afternoon
into this evening. Deep overrunning flow will continue to allow for
showers and storms to develop north of this boundary throughout the
day today and into tonight and warm advection mini spinny's continue
to work their way northward across the area. The best rain chances
shift northward this evening over interior portions of the forecast
area as the first upper shortwave zips quickly by. South of the
advancing boundary, low level flow has allowed for rich Gulf
moisture to surge northward leading to scattered warm advection
showers to develop. Interestingly enough, forecast soundings depict
a rather unstable zone under roughly 600 mb but heavily capped above
that. This will continue to support rather shallow convective cells
underneath the cap. Shallow doesn't mean they can't bite just might
fall under what we call "power showers" with no lightning. More on
that in the severe section below.

A brief respite will likely occur tonight as we fall in between
shortwave troughs and weak shortwave riding builds in. This break
will only be temporary as the next two waves move in on Wednesday.
The first shortwave likely moves through during the late-morning
through mid-afternoon hours. This first wave will spark off
scattered to numerous showers and thunderstorms, particularly over
the interior portions of the forecast area in the vicinity of the
Highway 84 corridor. We will likely see a respite in activity as we
head into late afternoon and early evening between shortwaves, with
a substantial uptick in overall coverage of showers and storms as
the next shortwave swings across into the early overnight hours.

Severe storms...Alright now for the part everyone is wondering
about. To be honest this is a rather subtle severe threat with a lot
of moving parts going on. This is far from a slam dunk event where
the confidence and ceiling is high, but more along the lines of a
tricky setup that could be nothing or could be a rather active
period featuring multiple rounds of storms, with the differences
between the two potentials being pretty small. So lets get to it.

For the rest of this afternoon into the evening hours we continue to
watch several mini spinny showers generally situated along and east
of the I-65 corridor. These will continue to progress inland within
a rather interesting environment. We continue to have the capping
inversion situated around 600 to 500mb layer which is helping to
keep convection shallow. Despite this, the low level profile is
quite unstable with nearly 150-200j/kg of 3km CAPE located over much
of the forecast area. Low level lapse rates are rather steep,
characterized by around 6.5 to 7C/km in the lowest 3km's. Moderate
wind shear is mostly confined within the lowest 3km layer with
hodographs decently curved with 150 to 200 m2/s2 of SRH in the
lowest kilometer to 3 kilometers. Main limiter for any more robust
potential with these power showers is lack of 3km bulk shear only
being around 25 to 30 knots and the capping inversion present
near 500mb. Best chance for any of these to try to be problematic
for a brief tor threat would be closer to the Highway 84 corridor
where the warm front is working its way northward to/stalling.

Now lets move on to the more substantial risk on Wednesday. We are
looking at two separate waves of strong to severe convection to
occur Wednesday. The first will be mainly across that same highway
84 corridor during the mid/late morning into the mid/late afternoon
hours. This will likely be along that stalled warm frontal zone that
extends just south of the I-20 corridor. North of this boundary
elevated storms will likely be ongoing with the potential for some
small hail given marginal mid-level lapse rates, weak storm
relative inflow and strong deep layer flow. I would not be shocked
to see a couple hail reports Wednesday morning mainly north of
highway 84. Morning and afternoon CAMs are generally becoming more
robust on the development of adequate instability near and north
of the Highway 84 corridor, with ample shear in place as the
shortwave begins to move across the region. Robust low level
instability and sfc-based CAPE will be present, with 3km CAPE
values in the 100 to 150j/kg range and sfc-based instability on
the order of 1,000 to 1,500j/kg. This combined with 50 to 60 knots
of deep layer shear and large, curved hodographs yielding 1km and
3km SRH values on the order of 200-250 m2/s2 and 300 to 350 m2/s2
will promote a severe weather threat with potential hazards
including damaging wind gusts and tornadoes. Storm mode overall
appears to be in the form of bowing segments and embedded
supercells for the late morning into afternoon hours.

The evening into overnight hours Wednesday night will be the
trickiest part of the forecast. A more substantial shortwave will
move across the area and the cold front will begin approaching from
the west. Afternoon convection will likely dictate the exact
positioning of the surface warm front/stalled boundary, which will
be one of the foci for more robust storm development early on where
semi-discrete supercells could materialize. Likewise, the
presence of a pre-frontal trough may also help instigate more
isolated thunderstorm development nearer the I-65 corridor,
however this may be removed far enough from better forcing for
ascent to help mitigate a more robust severe weather potential
there. Guidance does vary quite a bit on the exact evolution of
these features as they hinge on the evolution of the afternoon
convection. The further north the initiating boundary is, the
better the forcing that will be present for the development of
convection. Most the guidance is generally in agreement on the
eastward progression of the cold front, but as the prior shift
alluded to shear vectors become parallel to the initiating
boundary and any convection along the front may struggle to remain
surface based and repeatedly become undercut. Our main focus will
likely turn towards the aforementioned pre-frontal trough and
positioning of the warm front/stalled boundary for any more robust
severe potential. Overall environment will remain sufficient for
organized severe weather with around 1,000j/kg of surface based
instability maintaining itself into the overnight hours and large,
curved hodographs maintaining similar shear and SRH values as the
prior shortwave had to work with. Given this, the expectation
would be for a continued threat of damaging winds and tornadoes in
any of the more robust convection. Models seem to agree on
forcing lifting out during the mid to late overnight hours with a
decaying line of showers and storms prior to daybreak east of the
I-65 corridor. Overall, it appears the greatest threat for severe
weather will remain in the vicinity of the Highway 84 corridor,
with a diminishing threat with southward and eastward extent as
better forcing remains over interior counties.

Outside of convection, winds will be quite gusty Wednesday afternoon
into the evening hours. A strengthening low level jet to around 40
to 45 knots at 1km AGL and a deep mixed boundary layer up through
the 1 to 3km range will favor strong gusts to mix down to the
surface upwards of 30 to 35mph. While a wind advisory isn't
anticipated at this time, any further strengthening of the wind
field may result in higher wind gusts materializing so it is
something for us to keep an eye on moving forward. Temperatures
remain unseasonably warm with highs topping out in the upper 70's to
lower 80's Wednesday after starting the morning in the lower to
middle 60's inland and middle to upper 60's nearer the coast. North
of the aforementioned warm front early morning temperatures may
start in the upper 50's north of the Highway 84 corridor.
Temperatures fall quickly in the wake of the front Wednesday night,
generally lower to middle 50's west of I-65 and upper 50's to lower
60's east of I-65. MM/25 BB/8

&&

.SHORT TERM...
(Thursday through Friday night)
Issued at 322 PM CST Tue Feb 11 2025

Expect to start off the short term with a band of showers and
embedded storms translating eastward across the I-65 corridor
Thursday AM with a cold frontal passage. Chances of showers and
storms will lower and end from east to west respectively going
into the afternoon as the front moves deeper into the southeast
and strong high pressure begins to expand eastward across the MS
River Valley. With the expansive high over the OH/TN River Valley
Thursday night, rain-free weather is forecast. Much cooler too
with lows dipping down into the mid to upper 30's up along and
north of the US Hwy 84 corridor. Lower to mid 40's from there
south to I-10 and 47 to 52 at the coast. High pressure moves to
the Mid-Atlantic Friday and Friday night with the front stalling
out over the central Gulf. Clouds on the increase Friday and
Friday night with the passage of another subtle impulse caught up
in the west southwest flow aloft. The front over the Gulf responds
by returning northward as a warm front over LA late Friday. At
same time, deeper moisture overspreads the region and favors a
return to a slight chance to chance PoP. Highs Friday 66 to 71.
With increase cloud cover, lows Friday night more moderated. /10

&&

.LONG TERM...
(Saturday through Tuesday)
Issued at 322 PM CST Tue Feb 11 2025

Saturday and Saturday night, forecasters are watching the next
weather player to bring a threat of severe storms. Although we are
still 5 days out, the signal for severe weather remains in place for
Saturday afternoon into Saturday night. 11.12Z global spectral
weather models during this time-frame continues to suggest a zone
of broad diffluence aloft and strong deep layer shear spreads over
the Deep South as the axis of an energetic upper trough moves
east. Deterministic and ensemble mean guidance also suggest a
rather potent low-level jet strengthening to between 50 and 60
knots underneath the diffluent flow aloft spreading across Alabama
and Mississippi. Instability (Most Unstable CAPE's) 500-1000 J/kg
look to be in better phase with the intensifying low level
kinematics including where the best 0-6km bulk shear magnitudes
exist.

As a strong cold front moves east and serves as a surface based
focus for organized convection, a warm sector firmly established,
deep moisture, favorable shear and instability, forecasters are
looking at a solution supportive of severe storms. Forecasters are
becoming increasingly confident and concerned that an impactful
severe weather event may occur across the Deep South Saturday into
Saturday night. At this time though, there are still some
questions regarding timing and where the ingredients best line up
for the greatest potential. Mixed modes of severe storms too with
storms along what appears to be an organizing convective line to
move through would appear to have a higher damaging wind threat,
but any discrete storms out ahead of the main line could have a
higher tornadic potential. This being true of storms that latch
onto any northward propagating mesoscale boundaries which will
help to stretch updrafts which would also tend to rotate
considering forecast of Sfc to 3KM SRH values of 200-300 m2/s2
in place and curved hodographs. Right now, the latest long range
outlook from the Storm Prediction Center indicates a broad 15%
probability of severe weather equaling a Slight Risk 12Z Sat 2/15
to 12Z Sun 2/16 in place for LA, east northeast to AL. As we get
closer to the event and monitor trends, we will be able to refine
the forecast timing and impacts in greater detail.

The severe weather threat ends Sunday as the strong cold front
pushes east of the area. High pressure expands eastward over the
MS River Valley through early next week bringing a period of dry
weather.

In the wake of the frontal passage, temperatures trend cooler and
will bring a reminder that we are still in the cold season.
Coldest nights will be Monday and Tuesday mornings. Lows Monday
morning sink into the upper 20's in the interior to lower to mid
30's southern zones. Tuesday AM lows range near 30 up along US
Hwy 84 to the lower 40s along the coast. Coolest daytime highs in
the medium range looks to be Monday with numbers in the mid/upper
50's.

Hydrology: With the excessive rainfall forecast to be focused over
Northern MS to the southern Appalachians through the upcoming
week, local rivers are forecast to show a response with increased
stages going into the weekend. Some of those may reach action
stage or minor flooding levels. /10

&&

.MARINE...
Issued at 322 PM CST Tue Feb 11 2025

Onshore flow will continue to strengthen to moderate to strong
onshore flow late tonight into Wednesday morning, lingering through
late Wednesday night. Moderate to occasionally strong offshore flow
will follow in the wake of the front, strongest Thursday night into
Friday morning. Moderate to at times strong onshore flow returns
ahead of our next system this weekend, with moderate to strong
offshore flow returning Sunday, gradually relaxing into early next
week. A Small Craft Advisory goes into effect Wednesday morning
through Wednesday night, with additional Small Craft Advisories
likely needed throughout the late week into the weekend timeframe.
MM/25

&&

.PRELIMINARY POINT TEMPS/POPS...
Mobile      66  79  59  72  44  68  57  77 /  50  70 100  40  10  10  30  20
Pensacola   68  78  64  72  48  68  61  74 /  40  40  90  70  10  10  20  10
Destin      68  76  66  72  51  69  62  74 /  30  30  90  90  20  10  10  10
Evergreen   63  80  60  69  40  70  54  79 /  60  70 100  50  10  10  30  20
Waynesboro  59  80  50  64  38  67  52  79 /  90  90 100  10   0  20  40  40
Camden      59  80  54  64  37  66  52  77 /  90  80 100  30   0  20  40  30
Crestview   66  80  65  74  44  71  56  77 /  40  40  90  80  10  10  20  10

&&

.MOB WATCHES/WARNINGS/ADVISORIES...
AL...High Rip Current Risk from Wednesday morning through late
     Thursday night for ALZ265-266.

FL...High Rip Current Risk from Wednesday morning through late
     Thursday night for FLZ202-204-206.

MS...None.
GM...Small Craft Advisory from 6 AM Wednesday to midnight CST
     Wednesday night for GMZ670-675.

&&

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