River Flood Warning 15, NWS Mobile, AL

Area Forecast Discussion
National Weather Service Mobile AL
544 PM CST Sun Feb 11 2024

...New AVIATION...

.AVIATION...
(00Z TAFS)
Issued at 537 PM CST Sun Feb 11 2024

The first band of organized shra/tsra is lifting north of the
local area and we await the next period of redevelopment of better
coverage shra/tsra which is expected late in the night during the
morning Monday. In the meantime, a warm and moist environment
persists, favoring lowering flight rules in the near term with
streaks of shra lifting northeastward this evening. South winds 7
to 12 knots with occasional higher gusts. /10

&&

.PREV DISCUSSION... /issued 234 PM CST Sun Feb 11 2024/

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

NEAR TERM...
(Now through Monday)
Issued at 234 PM CST Sun Feb 11 2024

An upper low advances across the south central states through Monday
morning, then moves to near the Arkansas/Tennessee border Monday
afternoon. An associated surface low is currently located over
eastern Texas with a frontal boundary extending to across central
Mississippi and northern Alabama. The surface low advances to near
the Arkansas/Mississippi border late tonight before continuing into
eastern Kentucky late in the period, and in the process brings a
strong cold front through the forecast area on Monday. A series of
shortwaves continue to move across the forecast area ahead of the
approaching cold front. Timing the best deep layer lift associated
with this pattern has become increasingly difficult which in turn
makes for low confidence with how the associated convection will
play out. Indicated MLCAPE values could be as high as 1000-1500 J/kg
tonight into tomorrow (but will more likely be up to near 1000 J/kg)
before the front moves through, but model soundings continue to
exhibit characteristics that could hamper convective development.
The low confidence with the pattern also applies to how the model
soundings will evolve, but for the most part there are three main
concerns until the front moves through. The first is that there is a
tendency for unfavorable low level lapse rates which means that
convection may struggle to access much of the favorable low level
shear. The second is that a mid level warm layer is indicated for
much of the area before eroding from west to east late tonight into
early Monday morning. The third concern is that the column will
likely be steadily moistening which means that mid level dry air
essential for supporting a severe weather risk looks increasingly
dubious. The bottom line is that there is low confidence for how
convection will evolve, and as a consequence, the potential for
severe storms. CAMS (Convection Allowing Models) do indicate some
stronger storms developing but for the most part look to remain
below severe limits, adding to the low confidence for severe storm
development. It was noted that surf heights will be building on
Monday, so have opted to issue a High Surf Advisory which will be in
effect from 18Z Monday until 12Z Tuesday for surf heights of 5 to 7
feet. A marine Dense Fog Advisory will be in effect for Mobile Bay
and the Mississippi Sound until 6 am Monday, and will need to
monitor for the potential for dense fog to develop overnight, mainly
near the coast. Lows tonight will be rather mild and range from
around 60 to the lower 60s. Highs on Monday will be in the upper 60s
to lower 70s. A High Risk of rip currents continues through
Monday. /29

LONG TERM...
(Monday Night through Sunday)
Issued at 234 PM CST Sun Feb 11 2024

An upper-level trough located to the north of our region at the
start of the period quickly ejects northeastward throughout the
day on Tuesday. Behind it, the subtropical jet stream remains
in place over head as winds aloft slowly turn from southwesterly
to zonal by Wednesday and through the remainder of the week. At
the surface, a much cooler/drier airmass advects into our region
from our north as high pressure builds into the south central US
in the wake of the cold front which swept through our area during
the near term period. Dry, subsident air from this high will keep
rain chances out of the forecast through Thursday night as the
high slowly slides eastward. Temperatures will be rather cool
Monday night through Tuesday night, with lows generally in the mid
to upper 30s to low 40s. Highs on Tuesday will top out in the
upper 50s to low 60s. As the high moves overhead on Wednesday and
eventually to our east by Thursday, light winds will begin to
shift from offshore to onshore, allowing for temperatures to
gradually warm through the remainder of the week.

By Friday, a highly amplified trough, embedded within the
subtropical jet develops over the Eastern Pacific and begins to
quickly push eastward across Mexico on Saturday. As this trough
approaches, flow aloft turns southwesterly by late Friday allowing
for deep moisture (PWATs over 1.5 inches) to advect into the local
region from the Gulf. At the surface, a low pressure system looks to
develop over the northwest Gulf in association with the approaching
trough. Guidance continues to suggest that this low should remain
offshore as it pushes towards the east, keeping our area in the cool
sector. With the increase in moisture and ample forcing in place
from the proximity of the low, currently anticipating an overrunning
rain event, with scattered to numerous showers spreading across the
area Friday evening through Saturday. With models currently keeping
the low and its associated instability offshore, continued leaving
thunder out of the forecast for land areas at this time. However, as
the previous shift mentioned, if the surface low takes a more
northeastward trajectory and moves inland, then we will have to
monitor to see if the warm sector is able to move onshore,
increasing the potential for a few surface based thunderstorms. Rain
chances decrease from northwest to southeast on Sunday as the low
pushes to our east and a cold front moves through the area. /96

MARINE...
Issued at 234 PM CST Sun Feb 11 2024

With a continuing moist southerly flow over cool waters in Mobile
Bay (55-60F), have extended the marine Dense Fog Advisory for Mobile
Bay and the Mississippi Sound through 6 am Monday morning. Will need
to monitor for possible expansion of the advisory to include other
bay waters. Small craft should exercise caution for the open Gulf
waters tonight, then a Small Craft Advisory comes into effect for
much of the marine area on Monday then ends Tuesday morning as winds
and seas subside. Winds and seas will be higher near storms. /29

&&

.PRELIMINARY POINT TEMPS/POPS...
Mobile      61  69  38  60  36  63  42  68 /  90  90   0   0   0   0   0   0
Pensacola   63  69  42  60  39  63  46  67 /  70  90   0   0   0   0   0   0
Destin      64  70  45  61  42  63  49  66 /  70  90   0   0   0   0   0   0
Evergreen   62  71  38  60  33  66  39  69 /  80  90   0   0   0   0   0   0
Waynesboro  58  68  37  60  33  65  39  67 /  80  70   0   0   0   0   0   0
Camden      61  69  38  58  33  65  39  67 /  90  90   0   0   0   0   0   0
Crestview   63  72  41  61  33  65  39  69 /  70  90   0   0   0   0   0   0

&&

.MOB WATCHES/WARNINGS/ADVISORIES...
AL...High Rip Current Risk through Tuesday afternoon for ALZ265-266.

     High Surf Advisory from noon Monday to 6 AM CST Tuesday for
     ALZ265-266.

FL...High Rip Current Risk through Tuesday afternoon for FLZ202-204-
     206.

     High Surf Advisory from noon Monday to 6 AM CST Tuesday for
     FLZ202-204-206.

MS...None.
GM...Dense Fog Advisory until 6 AM CST Monday for GMZ630>632.

     Small Craft Advisory from noon Monday to midnight CST Monday
     night for GMZ631-632.

     Small Craft Advisory from 9 AM Monday to 9 AM CST Tuesday for
     GMZ650-655.

     Small Craft Advisory from 6 AM Monday to noon CST Tuesday for
     GMZ670-675.

&&

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