Rip Current in Alabama, April 13, 2022

Area Forecast Discussion
National Weather Service Mobile AL
418 PM CDT Wed Apr 13 2022

.NEAR TERM UPDATE /Now Through Thursday/...No significant changes
from previous forecast reasoning. The forecast challenge for the
remainder of the near term period will focus on the potential and
timing of severe weather and heavy rainfall starting this evening
and continuing into Thursday morning. A deep low pressure system
is expected to slowly lift across the Dakotas today. A vigorous
shortwave trough will round the base of this feature and lift
northeastward across the OK/KS/AR/MO region this afternoon and
then toward IL/IN/OH by this evening along a 90-110 kt 500 mb jet
streak. Our forecast area will be placed within a region of
increasing diffluence and differential divergence aloft by this
evening as the jet streak lifts northeastward over this part of
the country. An organized region of convection in the form of a
QLCS will take shape and move southeastward within this region of
forced ascent and should arrive into our southeast MS and interior
southwest AL counties by around 8-10 PM this evening. There is
still some question as to whether more discrete convection/cells
may initiate over portions of southeast MS and southwest AL late
this afternoon or early this evening prior to the arrival of the
main line of convection. The atmosphere will certainly be unstable
with up to around 1500 J/KG of MLCAPE available over this part of
the area along with 30-40 kt of deep layer shear and 30-35 kt of
low level flow. A slight warm nose from around 900-800 mb this
afternoon/early evening which will probably tend to suppress
convection prior to the arrival of the main line (when the cap
erodes) along the cold front. That said, we have noticed discrete
convection already developing back over portions of LA (west of
Baton Rouge) this afternoon, taking on a general northeasterly
motion. If the cap manages to erode, some of this convection could
arrive in our southeast MS by around 6 PM. The QLCS should move
from northwest to southeast across the forecast area through the
overnight hours, with some potential for additional convection to
re-develop across coastal portions of southwest AL and the western
FL panhandle through much of Thursday morning, if not part of
Thursday afternoon as the boundary potentially stalls near the
coast. It still appears that the primary severe weather threat
will be damaging wind gusts along the advancing QLCS tonight,
though a few instances of hail and an embedded tornado or two are
also possible.

Rainfall rates in association with the advancing QLCS could be
quite efficient, with many areas likely to pick up a quick 1-2" of
rain. There could be a few pockets of enhanced rainfall in excess
of 3-4" which could result in localized flash flooding tonight
into Thursday morning, especially across southeast MS and portions
of southwest AL. Confidence in larger scale flash flooding is low
enough to preclude a Flash Flood Watch issuance. We will continue
to advertise a limited flooding threat in our local graphics.

Persistent swell from the continued onshore flow will result in a
HIGH risk of deadly rip currents through at least Friday night.
Local lifeguards reported strong rip currents and 3-4 ft surf
heights at Orange Beach and Pensacola Beach this morning. /21

&&

.SHORT TERM /Thursday night Through Saturday night/...An upper low
over the Great Lakes shifts north as an upper ridge builds north
over the Rockies from high pressure centered over Mexico. Surface
high pressure centered over the Tennessee River Valley shifts east in
response to the building upper ridge, with southerly flow returning
to the Lower Mississippi River Valley and western portions of the
Southeast beginning Friday as the surface cold front that stalled
along the northern Gulf coast moves inland as a warm front. An upper
level shortwave system will pass northeast of the forecast area
Saturday, and with guidance advertising good moisture return ahead
of the system's passage (precipitable h20 values rising to around
1.5"-1.7" in the global models, a bit less in the mesoscale
guidance), showers and thunderstorms return to the Southeast. For
the forecast area, PoPs become likely Saturday afternoon, then
decrease into Saturday night as the upper energy moves off.

Looking at the chance of any strong to severe storms, instability is
minimal Friday, so that any storms should be minimal in strength.
Looking at Saturday, MLCapes rise into the 1000-1500J/kg range and
DCapes into the 800-1100 J/kg range. Looking at model soundings
for Saturday afternoon, there exists an elevated somewhat dry
layer that any taller storms may be able to grab and locally
enhance any downdrafts. Looking a winds, Bulk Shear values rise
into the 35-45kt range, enough for some organization to any
convection that forms, and with a general linear wind profile,
linear segments may organize with strong to damaging downbursts.

Temperatures around seasonal norms Thursday night quickly rise back
to above seasonal levels as upper subsidence, and moisture levels
increase as the warm front moves inland. Low temperatures Thursday
night will see the effects of a bit cooler air moving over mainly
northern portions of the forecast area, with low temperatures
ranging from the low to mid 50s well northwest of I-65 to low 60s
along the coast. Low temperatures in the 60s are expected Friday and
saturday nights. Temperature rising into the low to mid 80s inland
are expected Friday. The rain cools things off a bit Saturday, with
temperatures topping out in the 80-84 degree range across much of
the forecast area. Upper 70s are expected both days along the coast.

With persistent onshore flow returning to the area this weekend,
when combined with an increasing tidal range, a High Risk of rip
currents return to area beaches by Monday. /16

&&

.EXTENDED TERM /Sunday Through Wednesday/...An active upper
pattern over the northern half of the Conus will flatten the upper
ridge over the Rockies, bringing a west to east zonal upper flow
to the Southeast. Several rounds of upper level shortwave energy
move over the Southeast Sunday through Monday, bringing daily
showers and thunderstorms to the forecast area. With each passing
round of energy, a cold front moves a bit further south across the
Southeast, with the last being Monday into Monday night, moving
in a drier and cooler airmass over the forecast area. Above
seasonal temperatures start the Extended, with a bit below
seasonal temperatures expected Monday night through Wednesday. /16

&&

.MARINE...Moderate to at times strong onshore flow will precede a
slowing cold front moving over the Southeast and expected to stall
along the northern Gulf coast by Thursday night. Moderate to strong
northerly flow is expected behind the front, south to southwesterly
south. This front will wash out Friday, with onshore flow returning
to the area by Friday night. Another front will move over and south
of area waters early in  the coming week, bringing moderate to
strong offshore winds for the beginning of the week. /16

&&

.PRELIMINARY POINT TEMPS/POPS...
Mobile      63  78  57  80  64  81  64  81 /  90  60  10  20  20  50  30  30
Pensacola   67  78  62  79  66  78  66  80 /  70  80  10  20  20  50  30  30
Destin      67  76  63  78  67  76  67  78 /  40  80  20  20  20  50  30  30
Evergreen   61  77  56  83  62  81  62  79 /  80  60  10  20  30  60  30  40
Waynesboro  58  76  51  82  63  81  61  79 /  90  20  10  20  30  70  40  40
Camden      60  75  53  85  61  80  61  78 /  90  40  10  20  30  60  40  40
Crestview   64  78  60  83  62  80  64  81 /  50  80  20  20  20  50  30  30

&&

.MOB WATCHES/WARNINGS/ADVISORIES...
AL...High Rip Current Risk through late Friday night for ALZ265-266.

FL...High Rip Current Risk through late Friday night for FLZ202-204-
     206.

MS...None.
GM...None.
&&

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