Forecast Discussions mentioning any of "ACARS" "MDCRS" "AIRCRAFT" "TAMDAR" "AMDAR" "WVSS" received at GSD on 01/03/22

Area Forecast Discussion

National Weather Service Mobile AL

 550 PM CST Sun Jan 2 2022

.NEAR TERM UPDATE /Now Through Monday night/...Dramatic
atmospheric changes are underway across the CWA this evening in
the wake of a powerful cold front that is pushing through the
area. Across the FL panhandle into south-central AL temperatures
are hanging on in the lower to middle 60`s for the time being with
relatively dry conditions. This changes once you get to the I-65
corridor and points west where the surge of cold low level air
resides and some moisture overrunning the cold dome is resulting
in light rain showers and mist. It is in this area that
temperatures and dewpoints have already plummeted into the middle
to upper 40`s and should continue to precipitously fall through
the rest of the evening. Expect this to continue east and have
engulfed the entire CWA over the next few hours in much cooler
temperatures. The parent upper level trough will pivot east into
the CWA this evening with the 540dm heights reaching into the
northern portions of the CWA by late evening into the overnight
hours. Deep cold air through the column with only the near surface
being above freezing coupled with strong forcing for ascent and
residual low to mid level moisture may allow for a few isolated
showers or even a wintry mix of snow/sleet/rain to exist across
interior southeastern MS and interior southwestern AL. Biggest
reservations about appreciable wintry precipitation is a rather
dry dendritic growth zone, which would generally favor rather
light precip confined to mostly mist and a few gee whiz flurries
or sleet pellets. Outside of this area, expect primarily isolated
rain showers through late evening into the early overnight hours.

After precipitation exists the CWA by the early overnight hours,
temperatures will continue to fall into the upper 20`s near 30
along and northwest of the I-65 corridor, and lower to middle 30`s
southeast of the I-65 corridor. Monday will be a much colder day
compared to Sunday, with highs generally in the middle to upper
40`s for most locations. Some spots along the coast may manage to
crack 50 degrees. Monday night will once again be rather cold,
with lows dipping into the middle to upper 20`s northwest of the
I-65 corridor and lower to middle 30`s southeast of the I-65
corridor.

We still have several hazards in effect, and those are detailed
below:

Wind Advisory: A wind advisory remains in effect through 3AM CST
for coastal portions of AL/FL. Winds have been gusting upwards of
30 to 40mph across the advisory area this evening and are expected
to continue into the early overnight hours.

High Surf Advisory/High Risk Rip currents: A high surf advisory
continues for coastal AL/FL until midnight tonight. Waves of 5 to
8 feet are expected in the surf zone the rest of this evening. A
high risk of rip currents continues through Monday afternoon due
to the presence of dangerous rip currents. MM/25

&&

.AVIATION...
00Z issuance...A complex aviation forecast exists this evening
across the area. Generally MVFR to at times IFR ceilings are
making their presence known, and even at time MVFR visibility
owing to light to moderate mist with showers transiting the area.
Expect this to continue through around 06z, tapering off from west
to east. Over far interior southeastern MS and interior
southwestern AL, a brief wintry mix is possible but should provide
for no impacts to aircraft given the brevity and light nature of
it. MVFR to VFR ceilings and visibility return to the area mid to
late morning Monday. Very strong wind gusts persist across the
area this evening, particularly nearer the coast where
northwesterly winds gusting upwards of 30kts has been noted most
recently at KMOB and KBFM. These winds should taper off after 09z
to 10kts gusting 20kts. MM/25

&&

.PREV DISCUSSION... /issued 346 PM CST Sun Jan 2 2022/

NEAR TERM UPDATE /Now Through Monday/...Convection continues across
coastal sections of the western Florida Panhandle to the south of an
outflow boundary from morning storms. The airmass has been worked
over by a squall-line that moved through over the past hour or so,
therefore the threat for additional severe weather remains low at
this time. The threat for strong to severe storms will completely
end as the outflow sags south off the coast. Stronger storms may
linger a bit longer over the marine areas.

A strong cold front as of 20z extends from Thomasville, AL,
southwest to Gulfport, MS. This front will continue to progress
steadily eastward for the remainder of this afternoon and evening
with temperatures falling quickly behind the front.

A potent upper level level trough over the Arklatex will continue to
dig southeast through tonight. Large scale ascent associated with
this feature behind the front is resulting in an area of
precipitation falling into the cold air. This region of light
precipitation will spread back in from the west late this afternoon
and evening. Temperatures should cool sufficiently across interior
portions of southeast Mississippi and southwest Alabama, to the
north of Highway 84, to support a brief period of light snow or
mixed rain and snow before precipitation comes to an end after
midnight. At this time, precipitation should remain light and brief
enough to limit any accumulations. There is a small potential for a
light dusting of snow across extreme northern portions of Choctaw
into Wilcox counties. If this were to occur it would likely remain
limited to grassy surfaces, if it happens at all. So not
anticipating any hazardous travel at this time. We will monitoring
closely through the evening, but again not expecting driving
hazards.

Another issue will be strong winds that will persist areawide
through tonight under strong cold air advection. In fact, wind gusts
up to 40 mph will be possible along coastal Alabama and the western
Florida Panhandle tonight where a wind advisory has been issued.
Cloud cover should linger into at least tomorrow morning but with
strong cold advection, low temperatures should bottom out in the
middle 20s interior sections to the lower and middle 30s along the
coast. Wind chill values will likely drop into the middle teens to
lower 20s late tonight so make sure you are dressed properly to
protect against the cold temperatures expected.

Skies will gradually clear from southwest to northeast on Monday.
There is some potential for low clouds to persist over portions of
interior southwest and south-central Alabama into Monday afternoon.
Temperatures will remain cold on Monday with highs in the middle 40s
interior to the lower 50s along the immediate coast. /JLH

SHORT TERM /Monday night Through Wednesday night/...West to east
zonal upper flow over the Southeast Monday night sees a series of
passing upper level shortwave systems move through, forming a
shallow upper trough over the region through mid week. A pair of
stronger shortwave systems move east over the northern Conus,
digging a deeper upper trough over the Plains/Mississippi River
Valley. The active upper pattern shifts surface high pressure over
the Central Plains quickly eastward, to over the East Coast by
Tuesday evening and over the Atlantic thereafter. A surface ridge
stretching south along the East Coast weakens with the exiting
surface high, leaving the Southeast under weak onshore flow mid
week. With the weak onshore flow comes weak moisture return, and
precipitable h20 values rising to around 1.0", mainly near the coast.
A shortwave system moves through the southern end of the upper
trough and over the Southeast Wednesday night into the Extended.
Increasing inconsistency continues between the operational guidance,
with the op ECMWF advertising a more northerly upper trough forming
along with a bit better organized surface ridge over the Southeast,
bringing a bit warmer and wetter forecast than the op GFS. The
GEFS and ECMWF ensembles are advertising an in between solution,
so have went that way with the forecast. Low temperatures Monday
night in the mid 20s to low 30s inland, mid to upper 30s along the
coast moderate into the upper 40s to low 50s inland, mid/upper
50s along the coast as southerly flow returns. High temperatures
in the mid 50s to near 60 Tuesday moderate upwards into the mid to
upper 60s Wednesday. A slight chance of rain showers return to
the forecast area Wednesday night.
/16

EXTENDED TERM /Thursday Through Sunday/...A second strong shortwave
system moves through the mean upper trough over the eastern Conus
with a weak ridge developing over the Plains, then moving over
and east of the East coast through Saturday into the coming week.
More shortwave energy digs a mean upper trough over the western
Conus Sunday into the coming week, with energy in the southern end
over the southwestern Conus/Mexico ejecting eastward. A weak cold
front moves over the forecast area Thursday through Thursday
night, ushering a drier, but not appreciably cooler airmass over
the Southeast. Surface high pressure over the Plains moves quickly
east, to over then east of the East coast Saturday into Sunday.
Guidance is advertising a more organized surface ridge moving over
the Southeast from this surface high next weekend, with better
moisture return over the Southeast. With a series of upper level
shortwaves moving over the Southeast and better moisture to work
with, the Extended becomes a wetter one, with a chance of showers
and slight chance of thunderstorms through the period. With the
weak ridge, temperatures rise to about 10 degrees above seasonal
norms.
/16

MARINE...A strong cold front is currently entering the Mobile Bay
region, and will continue moving east across the remainder of the
marine area late this afternoon and be clearing the marine area to
the east by early this evening. Showers and isolated thunderstorms
will be ending with the frontal passage. In the wake of the front, a
strong northwest flow producing gale force winds is expected to
begin this evening and continue into Monday morning. A Gale Warning
is in effect for all of the marine area through 4 AM CST Monday. In
addition, since the strong northwest winds will initially be flowing
against the swell expect seas to be confused. Seas build to around 6
to 8 feet near shore and up to around 8 to 10 feet further offshore
through tonight. Winds and seas are expected to decrease by midweek
with a lighter east to southeast flow developing. /12

&&

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

     High Surf Advisory until midnight CST tonight for ALZ265-266.

     Wind Advisory until 3 AM CST Monday for ALZ263>266.

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

     High Surf Advisory until midnight CST tonight for FLZ202-204-206.

     Wind Advisory until 3 AM CST Monday for FLZ202-204-206.

MS...None.
GM...Small Craft Advisory from 4 AM to noon CST Monday for GMZ630>636-
     650-655-670-675.

     Gale Warning until 4 AM CST Monday for GMZ630>636-650-655-670-
     675.

&&

$$

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