Area Forecast Discussion
Issued by NWS Mobile, AL

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FXUS64 KMOB 250416
AFDMOB

Area Forecast Discussion
National Weather Service Mobile AL
1116 PM CDT Sun May 24 2020

.NEAR TERM /Now Through Monday night/...Upper air map analysis
this evening shows an amplified pattern at high levels with a trof
axis aligned from Montana southward to the Rio Grande valley. On
the eastern flank of the trof axis, forecasters see an enhancement
to deep layer ascent from the coupling of the high level jet
structure. A right rear entrance region of an 80 kt jet streak
lifting up across the central Plains coupled with a left exit
region of 80 to 90 kt streak diving southward over the Four
corners of the Desert southwest has supported the formation of a
lengthy, nearly solid area of storms area concentrated lightning
from Kansas to southern TX. Meanwhile, a weak inverted low level
trof was aligned over the FL Peninsula out across the southeast
Gulf. Memorial Day Monday sees the large scale trof migrating
eastward over the Plains, supporting the northward passage of mid-
level impulses over the deep south. Meanwhile, the low-level trof
over the FL Peninsula lifts northward and also may pose a
contribution to the overall forcing supporting scattered storm
coverages during the instability of the day as environmental
moisture remains sufficient. Will maintain a chance of showers and
storms into the evening, carrying over from the afternoon.

The increasing cloud cover and precipitation will limit daytime
heating somewhat, than seen past few days with highs Monday
expected to range from 84 to 89 degrees, with lower 80s at the
coast. With low level winds and swells increasing along the
beaches, a High Rip Current Risk begins on Monday. Overnight lows
Monday night to remain warm and muggy. /10



&&

.PREV DISCUSSION... /issued 641 PM CDT Sun May 24 2020/

AVIATION...
00Z issuance...Scattered tsra has worked northward to along the US
Hwy 84 corridor. Lingering evening tsra will be most impactful by
bringing strong and variable convective wind gusts and brief
reductions to vsby in moderate to heavy rain. Southward and closer
to coast, convection is very isolated. All activity is forecast to
decrease in coverage by 25.03Z, earlier over the coast. Away from
tsra, winds light. VFR conditions. After storms decay, will be
lingering mid to high based cigs. /10

PREV DISCUSSION... /issued 357 PM CDT Sun May 24 2020/

NEAR TERM UPDATE /Now Through Monday/...An upper ridge will
continue to build over the eastern conus from the western Atlantic
through the near term. Meanwhile, an upper trough over the
Rockies, with a southeastward extension over the Gulf of Mexico,
will continue to move eastward over the Great Plains. Will see an
increase in coverage of rainshowers and thunderstorms this
afternoon and evening hours generally north of I-10 due to
decreased stability. Enough instability is indicated (MUCapes
topping 2000J/kg in the heat of the day) for strong storms to
develop. Also, with DCapes again topping 1000J/kg and dry air in
the mid/upper levels, strong winds are possible if this dry air
mixes in to any downdrafts of the taller storms. Small hail will
also be possible with wetbulb zero heights around 11,000-12,000`.
High temperatures today are trending as forecast, topping out in
the 88 to 93 degree range over most of the forecast area, with mid
80s close to the coast.

An upper level shortwave trough moving through the mean gulf upper
trough late tonight through Monday afternoon will move north over
the north-central/northeastern Gulf coast. Increasing coverage of
convection is expected to spread north over the northern gulf late
tonight through Monday, with the best coverage expected along the
coast near the best upper dynamics from the shortwave trough.

Low temperatures tonight are expected to range from 65 to 70
degrees, with low 70s at the coast. The increasing cloud cover and
precipitation will limit daytime heating, bringing a cooler day
to the forecast area for Memorial Day than previous days. High
temperatures Monday are expected to range from 84 to 89 degrees,
with low 80s at the coast. With the cooler temperatures over a
significant portion of the forecast area, the chance of strong
storms decreases significantly. With low level winds and swells
increasing along the beaches, a High Rip Current Risk begins on
Monday. /22

SHORT TERM /Monday night Through Wednesday night/...A moist and
difluent flow pattern aloft will continue over the the area
downstream of a cutoff upper low over Texas. Meanwhile, a upper
ridge will extend from the western Atlantic through the mid-
Atlantic states. The difluent flow aloft combined with
disturbances rotating through the southwest upper flow will lead
to continue scattered to locally numerous showers and
thunderstorms. The showers and storms will be most numerous during
peak heating hours, but will linger into the evening due to the
previously mentioned features. With the moist airmass remaining
entrenched across our region, a few showers may tend to re-develop
overnight, especially near the coast. Highs will generally be in
the mid and upper 80s depending on if/when a site receives rain.
/13

EXTENDED TERM /Thursday Through Sunday/...The pattern changes
little through the extended term as the local area remains between
an upper cutoff low to the west and a weak upper ridge to the
east. At the surface, high pressure remains firmly in place over
the western Atlantic and eastern Gulf. The result will be a
persistent moist and unsettled deep-layer southerly flow across
the region through the period. With this pattern, expect shower
and thunderstorm activity to develop across the area each day,
becoming most numerous during peak heating hours along an inland-
advancing sea breeze. Moderate instability and weak shear will
support a primarily pulse-type thunderstorm mode, though can`t
rule out a few multi-cells capable of producing frequent
lightning, gusty winds, and small hail. While activity should
decrease after sunset each evening, decided to leave in low-end
PoPs each night as weak instability will remain in place and some
areas could see a few showers and storms form along leftover
outflow boundaries.

Temperatures remain steady through the period, with highs reaching
the mid to upper 80s (and perhaps a few locations reaching low 90s)
each afternoon. Low temps each night only dip into the upper 60s
inland to low/mid 70s along the coast. /13

MARINE...A strengthening surface ridge along the eastern U.S.
coastline to the northeast Gulf of Mexico will bring moderate to
strong easterly flow and building seas beginning tonight and lasting
into Tuesday. Winds will then ease to light to moderate from the
south to southeast for the remainder of the forecast. /22

&&

.MOB WATCHES/WARNINGS/ADVISORIES...
AL...High Rip Current Risk from 6 AM CDT Monday through late Tuesday
     night for ALZ265-266.

FL...High Rip Current Risk from 6 AM CDT Monday through late Tuesday
     night for FLZ202-204-206.

MS...None.
GM...Small Craft Advisory until 11 AM CDT Tuesday for GMZ650-655-670-
     675.

     Small Craft Advisory from 6 AM Monday to 11 AM CDT Tuesday for
     GMZ631-632.

&&

$$

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