High Surf Advisory 5, NWS Mobile, AL

Area Forecast Discussion
National Weather Service Mobile AL
1246 PM CDT Thu Mar 13 2025

...New Aviation...

.DISCUSSION...
Issued at 438 AM CDT Thu Mar 13 2025

Now through Friday night...

An upper level shortwave will swing east across the forecast area
today giving some upper support for any showers and thunderstorms
that develop. The overall environment across our area from mid-
morning through mid-afternoon today will become sufficient for the
development of marginal risk of severe weather, primarily over
interior sections of southwest AL and south central AL as well as
over portions of the western FL panhandle. MLCAPE values during
this timeframe should be around 500-1000 J/KG (possibly up to
around 1200 J/KG in some locations). The highest MLCAPE values
still appear to be concentrated across south central Alabama from
mid-morning to mid afternoon and still collocated with a small
area of favorable lift due to the passing shortwave. With mid-
level lapse-rates initially up to around 7.5 C/KM due to cool air
aloft, along with long hodographs, large hail is the primary
threat with the strongest thunderstorms, and perhaps some strong
gusty winds as well.

As the shortwave axis moves off to the east of our area by late
afternoon chances for storms decreases from west to east. We then
expect a dry forecast for tonight through most of the day Friday
as our forecast area will be between weather systems. Friday
night, a second system will be approaching from the west, with
increasing chances for showers and thunderstorms as we go through
the overnight hours. Highest rain chances will be over our
northwestern zones late Friday night, where good chance to low-end
likely PoPs are forecast. As this weather moves in from the west
and northwest late Friday night, there will be the potential for
severe storms over our northwest zones, mainly north of a general
Waynesboro-Grove Hill- Camden line. Surface based CAPE may be
around 1000 J/KG but lowest level lapse rates may be somewhat
marginal. Still, damaging winds and large hail could be possible
with these potential storms over our far northwestern zones late
Friday night, and the tornado potential cannot be completely ruled
out either.

Daytime high temperatures mainly in the 80s inland areas both
today and Friday with mid to upper 70s closer to and along the
coast. Nighttime lows , with nighttime low temperatures in the
lower 60s tonight and the low to mid 60s Friday night. DS/12

Saturday through Wednesday...

All eyes are on the severe weather set-up for Saturday and the
trends have, unfortunately, not our friend in the model guidance
over the past 24hrs or so.

The stage will be set for severe storms - likely significant
severe storms - as we move into Saturday. The lead shortwave will
be jet setting off into the Great Lakes region in the morning as a
secondary, more subtle shortwave rounds the base of a potent
trough barreling across the Plains. This trough quickly slides
toward the Mississippi River Valley as the secondary shortwave
acts to amplify the trough. Meanwhile, the initial surface low
(associated with the lead shortwave) pivots into the Upper Midwest
while a wave of low pressure attempts to develop somewhere to our
west across coastal Texas or Louisiana in the morning. This would
lead to a weak warm front lifting out of the Gulf through our
area early on Saturday. That said, much of the guidance washes out
the secondary low rather quickly. Deep onshore flow develops
ahead of this system as rich Gulf moisture funnels into the area.
PWATs surge to 1.8+ inches on Saturday. There will be ample
instability (MLCAPE of 1500+ J/kg) and shear (50+ knots at 0-3km
and nearly 40 knots at 0-1km) in the afternoon on Saturday as the
southerly low level jet begins to crank (60+ knots at 850mb).
Steep mid-level lapse rates (7+ °C/km) will be in place for much
of the afternoon, although lapse rates will be slightly higher in
the early morning hours in comparison to the afternoon.

Convection will be ongoing as we roll into Saturday morning. Don't
expect to wake up and see a ton of storms on radar that morning,
it'll still be rather isolated throughout the morning hours. The
main threats in the early morning hours remain large hail and
strong winds. While we cannot rule out tornadoes in the early
morning, that threat is higher as we get later in the day. As we
roll into the afternoon, a proverbial switch will flip and
conditions will quickly deteriorate with scattered to numerous
convection in the form of supercells. This evolution hinges on the
convection overnight and in the pre-dawn hours - do the early
storms contaminate the warm sector or not is the question at hand.
At this point, the guidance is indicating that there will be
limited storms in the morning hours, which will preserve
(unfortunately) the environment for the afternoon and
evening...hence why SPC upgraded much of the area to a MODERATE
RISK (level 4 of 5). That risk was driven largely by the
increasing probability for tornadoes...strong tornadoes.
Regardless of how the pristine the warm sector is or is not on
Saturday, a potent squall line (potentially a broken line of
supercells) will slide across the area from west to east. The line
will likely reach our southeast Mississippi counties late in the
afternoon and push east of our counties in Alabama and Florida
either in the overnight hours or by early Sunday morning. Note -
We will continue to refine the forecast as we draw closer to the
day and night of the event, so continue to check back for more
information as the evolution, severity, and timing are all subject
to change at this point.

In the wake of the cold front (that we just now realized we forgot
to mention in the last paragraph), the area dries out Sunday night
through at least Wednesday. Next chance for showers and storms is
late next week.

Beach and Coastal Forecast - Increasing southerly flow will lead
to several coastal and beach issues this weekend. The rip current
risk remains HIGH Saturday through Sunday night. Surf quickly
increases on Saturday with the potential for 6-8 foot breakers
(potentially higher). Surf begins to subside on Sunday but still
remains near advisory criteria through the day. Minor coastal
flooding is looking possible on Saturday, especially in the
afternoon, as water levels rise due to the strong southerly flow.
07/mb

&&

.AVIATION...
(18Z TAFS)
Issued at 1246 PM CDT Thu Mar 13 2025

Some brief reductions to MVFR may be associated with some of the
showers or storms today east of I-65 this afternoon. Winds
primarily light southerly, but moderate at time especially near
the coast. Another round of low clouds and fog, likely more
widespread across the region, is expected tonight with VLIFR and
LIFR conditions likely late tonight into Friday morning. /22

&&

.MARINE...
Issued at 438 AM CDT Thu Mar 13 2025

A light to occasionally moderate southerly flow will continue
through early Friday and then strengthens significantly late
Friday through Saturday as a cold front approaches from the west.
Conditions will become hazardous for small craft by late Friday
and continue through Saturday night. Small Craft to Gale
conditions will be possible on Saturday. The front moves through
late Saturday night into Sunday with winds becoming northwesterly
and gradually decreasing late Sunday into Sunday night. Light to
occasionally moderate offshore flow early into early Monday
decreases and become mainly light east to southeasterly by the
middle part of next week. DS/12

&&

.PRELIMINARY POINT TEMPS/POPS...
Mobile      61  80  65  78  56  74  44  71 /   0  10  40  90  60  10   0   0
Pensacola   64  76  67  75  61  74  48  69 /   0   0  20  70  80  10   0   0
Destin      63  75  65  75  64  75  50  69 /   0  10  10  70  90  20  10   0
Evergreen   60  83  64  80  56  74  41  70 /   0   0  30  90  90  10   0   0
Waynesboro  60  83  64  78  52  70  40  71 /   0  10  70 100  40   0   0   0
Camden      60  82  66  77  55  71  41  68 /   0   0  50  90  80  10   0   0
Crestview   58  80  62  79  58  77  42  71 /   0   0  20  80  90  20  10   0

&&

.MOB WATCHES/WARNINGS/ADVISORIES...
AL...None.
FL...None.
MS...None.
GM...None.
&&

This product is also available on the web at:
www.weather.gov/mob