Area Forecast Discussion
Issued by NWS Mobile, AL

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FXUS64 KMOB 270321
AFDMOB

Area Forecast Discussion
National Weather Service Mobile AL
1021 PM CDT TUE JUL 26 2016

.DISCUSSION...Updated for latest marine discussion below.

&&

.MARINE...Winds have begun to abate as the gradient relaxes but buoy
42012 44 NM South of Orange Beach still observing sustained winds
near 20 knots with higher gusts and wave heights up to 7 feet. As a
result have continued the Small Craft Advisory for the Gulf Waters.
Although the advisory expired for the Mississippi Sound and Southern
Mobile Bay...winds of 15 to 20 knots will create cautionary
conditions for small craft. /08


&&

.PREV DISCUSSION... /issued 936 PM CDT TUE JUL 26 2016/

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

UPDATE...The upper level low pressure system has continued to shift
west and the main surface trough has pushed inland. As a result,convection
over the forecast area has become increasingly sparse. Showers should
remain generally confined to our more coastal counties and over the
marine area tonight. The convective pattern tomorrow will follow a
more typical diurnal summer pattern...initiating along the coast in
the morning then moving inland during the day and dissipating in the
early evening. Gradient is starting to weaken so winds along the
coast and over the marine area are starting to abate. /08

PREV DISCUSSION... /issued 707 PM CDT TUE JUL 26 2016/

DISCUSSION...See updated information below.

MARINE...The tightening gradient between the low pressure system
over the northern gulf and surface high pressure ridging in from the
Western Atlantic has increased the winds over the marine area. The
Gulf waters between Pascagoula, MS and Pensacola, FL as well as the
Mississippi Sound and Southern Mobile Bay are expected to experience
winds of 20 to 25 knots with higher gusts through around 10 PM this
evening. Other waters should see winds in the 15 to 20 knots. The
gradient should gradually subside with winds falling off to around
15 knots offshore and around 10 knots over protected waters. Showers
should decrease in coverage overnight. /08

AVIATION...
00Z issuance...Convection should decrease in coverage as the evening
progresses but increase again tomorrow morning and afternoon. VFR
conditions will be the norm but moist southerly flow over the region
and shower activity will create pockets of occasional MVFR...patchy
fog to is possible over more interior locations. Gusty south to
southwesterly winds along the coast will diminish this evening and
pick up again by mid morning. /08

PREV DISCUSSION... /issued 422 PM CDT TUE JUL 26 2016/

NEAR TERM /Now Through Wednesday/...Weak mid to upper low pressure area
just off the tx coast will begin to drift inland later tonight and
on wed eventually becoming absorbed by a passing short wave trof
tracking east over the mid section of the country later in the week.
At the sfc weak low pressure was reflected just south of the ms/al
coast earlier this morning has shifted west over lower parts of la
this afternoon with a weak sfc trof still extending east from the low
center...stretching across coastal areas of al and nwfl this
afternoon. This pattern is expected to continue near the sfc through
wed morning then weaken and lift northward by afternoon as the upper
system to the west shifts north. As a result expect scattered to
numerous showers and thunderstorms to continue across the region
through wed morning...similar to the last 24 hours...then weaken from
east to west as the weak sfc trof lifts northward and becomes
diffuse. Latest model soundings support this reasoning showing a deep
southerly flow across the region through wed resulting in pwats
between 2.1 to 2.3 inches through wed midday then lowering to less
than 2 inches over eastern parts of the forecast area by mid
afternoon on wed. Due to weak forcing aloft combined with marginal
lapse rates in the mid to upper levels the threat for severe weather
will remain low...with only short periods of very heavy rain possibly
resulting in some minor or localized flooding in areas with poor
drainage. Some of the stronger storms by afternoon could also produce
occasional lightning and gusty winds between 20 and 30 mph.

As for temps lows tonight will continue to range from the mid to
upper 70s inland and the upper 70s to lower 80s near the coast...due
to the deep southerly flow and tropical moisture in place. Highs on
wed will reflect this also with temps still below seasonal averages
ranging from the mid to upper 80s to the west and along the coast and
the lower 90s to the east. 32/ee

SHORT TERM /Wednesday night Through Friday night/...Forecast upper
air maps indicate that a deep layer ridge will be in place off the
southeast coast to begin the short term, which will extend west into
portions of the forecast area. A break in the ridge is positioned
across the Lower MS River Delta, down across LA to across the
western Gulf. This pattern holds into the remainder of the week.
Initially, the higher deep layer moisture lifts northwest of the
local area, pooling into the upper level shear zone/weakness and
decaying surface trof over the Mid-South Wed night. This results in a
lowering in rain chances. For Thu, have a slightly higher chance of
storms west of I-65 where the western flank of, and weaker portion of
the deep layer ridge is set up. Heading into Fri, a more typical
diurnal summer-time convective mode is expected during the heat and
instability of the day with a modest chance of showers/storms, while
lower chances follow Fri night. Highs both Thu and Fri in the lower
to mid 90s interior. 87 to 91 along the beaches given trajectory of
flow off the Gulf. Overnight lows change little, lower to mid 70s
interior to close to 80 at the beaches. /10

LONG TERM /Saturday Through Tuesday/...Southwest Atlantic mid-level
ridge remains amplified into the weekend...but the western periphery, of
which that noses across the central Gulf coast, is progged to be in
more of a flattened state. Meanwhile...an upper trof axis across the
Mid-Mississippi River Valley, southward to the Mid-South this
weekend...eases eastward to the Appalachians, into the southeast
early next week. With pwat values near 2 inches along with daily
instability and modest layer lift with the eastward translation of
the trof axis to our north, will maintain the higher chance of
typical summer-time storms each day. Lower chances anticipated each
night as local environment stabilizes. Little change in daily highs
and night- time lows. /10

MARINE...A weak sfc trof near the alabama and mississippi coast will
drift northward and become diffuse through late wed afternoon.
Further west an upper low near the tx coast will shift northward and
weaken by late wed...leading to a moderate to strong southerly flow
over the marine area through early wed then diminish later in the day
as the upper system to the west shifts north. Seas up to 5 feet will
continue through tonight subsiding slowly by wed afternoon. A light
onshore flow is then expected later in the week as high pressure
rebuilds over the north central gulf. 32/ee

&&

.MOB Watches/Warnings/Advisories...
AL...High Rip Current Risk until 7 AM CDT Wednesday for ALZ265-266.

FL...High Rip Current Risk until 7 AM CDT Wednesday for FLZ202-204-
     206.

MS...None.
GM...Small Craft Advisory until 1 AM CDT Wednesday for GMZ650-670.

&&

$$

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