Area Forecast Discussion
Issued by NWS Mobile, AL

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FXUS64 KMOB 280029
AFDMOB

Area Forecast Discussion
National Weather Service Mobile AL
729 PM CDT SAT AUG 27 2016

.DISCUSSION...See updated information for land areas below.

&&

.UPDATE...Shower activity has rapidly dissipated this evening so have
scaled back activity for the remainder of tonight. Kept a dry
forecast throughout most the forecast area overnight. Kept a slight
chance over the marine area and closer to the coast where minor waves
traveling along the deep layer easterly flow could trigger some spotty
light shower activity. /08

&&

.PREV DISCUSSION... /issued 646 PM CDT SAT AUG 27 2016/

DISCUSSION...Updated for latest aviation discussion below.

AVIATION...
00Z issuance...Predominantly VFR conditions expect to prevail
through the next 24 hours. Isolated to scattered shower/TSTM activity
tomorrow morning/afternoon could potentially create some spotty
tempo MVFR conditions. /08

PREV DISCUSSION... /issued 424 PM CDT SAT AUG 27 2016/

NEAR TERM /Now Through Sunday/...Latest radar loops continue to show
isolated to scattered showers and thunderstorms forming over the
marine area moving inland generally from Pensacola Fl to Pascagoula
Ms and westward. General movement was to the west northwest at 10 to
15 mph. Further development...mostly scattered in coverage or
less...can be expected generally south of a line stretching from
Mobile Al to Crestview Fl. Gusty straight line winds up to 40
mph...frequent lightning and brief periods of very heavy rain can be
expected with the stronger thunderstorms through early to mid
evening. Best forcing aloft moving in from the east can be expected
through tonight followed by less forcing during the day on Sun.

Upper ridge of high pressure over much of the central gulf and se
states continues to shift slowly to the north and east through the
weekend. Near the sfc high pressure will continue to weaken from
south to north through Sun afternoon mostly in response to invest
99L shifting west over the fl straits and se gulf. Sfc winds will
continue from the east southeast this afternoon and early
tonight...shifting northeast overnight and early sun...then
rebuilding from the east southeast on Sun helping to usher better
low level moisture over most of the lower half of the forecast area
through early in the week. Latest model soundings depict this well
with pwats increasing to 1.9 to 2.0 inches over most coastal areas
later tonight continuing through Sun. As a result the best coverage
of showers and thunderstorms will continue in these areas through
Sun afternoon with thunderstorms remaining below severe limits due
to marginal instability and forcing.

Tonights lows will fall to the lower to middle 70s for most inland
areas generally along and north of the I-10 corridor and mid to
upper 70s further south towards the immediate coast. Highs Sun will
be a tad cooler with highs climbing to the lower to middle 90s
inland and the mid to upper 80s close to the coast. 32/ee

SHORT TERM /Sunday night Through Tuesday night/...A weak surface
ridge of high pressure along the southern appalachians will remain
in place through Monday and then begin to weaken on Tuesday.
Meanwhile, the upper level ridge of high pressure extending from the
Ohio River Vally eastward over the Virginias to the western Atlantic
Ocean will also remain in tact and then split in two on Tuesday as an
upper shortwave dives southeast over southeast Canada and the
northeast conus regions. Meanwhile the tropical wave "Invest 99L"
slowly moves west-northwest from the Florida Straits and into the
southeastern Gulf of Mexico through Tuesday. There is still a high
amount of uncertainty regarding the track and strength of this
feature through Tuesday, but the available short range guidance seems
to be in agreement with keeping the wave fairly weak. A dry and
subsident airmass generally stays intact over locations generally
along and north of U.S. Highway 84 underneath the influence of the
ridge axis Monday and Tuesday, where precipitable water values should
range between 1.25 and 1.5 inches. We will maintain a dry to only
isolated coverage of showers and thunderstorms over this portion of
the region through the short term. However, better moisture will
extend across central and especially southern portions of the
forecast area, with precipitable waters trending between 1.5 and 2.0
inches. The increased moisture will support development of isolated
to scattered showers and thunderstorms, with the best coverage across
our southwest zones and near the coast. Convection should diminish
with loss of daytime heating, but enough moisture and over-running
may remain in place to keep a slight chance to chance of showers and
storms near the coast Sunday night, with dry conditions expected
Monday night.

Seasonably hot/humid conditions will otherwise persist, with highs
in the lower to mid 90s inland and around 90 near the coast both
Monday and Tuesday. Lows will be in the lower to mid 70s inland
areas, except upper 70s to around 80 degrees near the immediate
coast and beaches. /22

LONG TERM /Wednesday Through Saturday/...Much uncertainty continues
in the extended forecast range and largely depends upon the eventual
development (if any) and associated track of 99L. The National
Hurricane Center has kept the development chances of this system at
40% over the next 5 days, or through 2 pm Thursday. The 12Z GFS still
moves the system northward over the eastern Gulf through midweek,
while the slower ECMWF takes 99L further west and strengthens the
system over the central Gulf through Thursday, while other medium
range model guidance continues to offer a variety of solutions. We
will continue to closely monitor this system over the next several
days for development. For the latest information regarding Invest
99L, please check the National Hurricane Center website at
http://www.nhc.noaa.gov and our website at http://weather.gov/mob.

We have otherwise continued to follow a blended approach to the
extended forecast, generally keeping POPs fairly low in the isolated
to low-end scattered coverage range on Wednesday and Thursday, then
trend the coverage upward just a bit toward the end of the week.
Little variation in day-to-day temperatures is indicated through the
extended period, with highs each day in the lower to mid 90s inland
and closer to 90 near the coast, with lows each morning in the 70s.
/22

MARINE...High pressure will continue to weaken over the northern
gulf mostly in response to invest99L moving west into the se gulf
early Sun night into Mon. Latest model guidance does show this
system on a westerly track in the gulf early in the week then
turning northward towards the north central gulf later in the week.
With this a moderate easterly flow will continue through midweek
possibly building from the east later in the week along with tides
running above predicated levels. As a result mariners along the
north central gulf coast should continue to monitor conditions in
the lower gulf and stay tuned for further updates from the National
Hurricane Center and your local WFO in Mobile Al.  32/ee

&&

.MOB Watches/Warnings/Advisories...
AL...None.
FL...None.
MS...None.
GM...None.
&&

$$

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