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Area Forecast Discussion...UPDATED
National Weather Service Mobile AL
1238 PM CDT WED JUL 27 2016

.DISCUSSION...Updated for latest aviation discussion below.

&&

.AVIATION...
18Z issuance...Radar shows clusters of shra/tsra over the interior
lifting northeast. Additional development is forecast over the terminals
thru the afternoon. Cigs are forecast at MVFR categories with passage
of any tsra reducing vsby briefly to IFR/MVFR categories. Away from
storms, a general southwest flow is forecast thru the afternoon at 9
to 14 kts with occasional higher gusts at times. /10

&&

.PREV DISCUSSION... /issued 1130 AM CDT WED JUL 27 2016/ 

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

UPDATE...Deep layer ridge of high pressure extends from off the
southeast US coast, westward to the far eastern portions of the
state of MS. A weakness in the ridge axis is situated from the Mid-
South to LA and down into the western Gulf. Within the weakness, a
complicated surface pattern exists with a quasi-stationary surface
frontal boundary positioned from the Ohio River Valley to across the
Mid- South, while a weakening surface trof eases in from the
northwest and will eventually merge/phase with the frontal zone. Deep
layer moisture continues to be high over the central Gulf coast with
precipitable water values from 2 to 2.2 inches being between 130 and
150% of normal. Considering more than adequate moisture, the close
proximity of the high level shear zone just to our west and
instability (Most Unstable Convective Energy 2000-3000 J/Kg)...will
leave in a mention of scattered showers and storms over most of the
area thru the remainder of the day. Lingering evening activity is
expected before chances lower to 10% or less after midnight. Will
leave forecast highs as is, in the upper 80s/lower 90s. Of course,
with the passage of showers and storms over any one area will bring a
substantial drop in temperatures by some 10 to 15 degrees due to the
passage of rain-cooled outflow boundaries.

High risk of rip currents continues along area beaches today. 

PREV DISCUSSION... /issued 717 AM CDT WED JUL 27 2016/ 

DISCUSSION...Updated for latest aviation discussion below.

AVIATION...
27/12Z issuance...Generally VFR conditions are expected for the 
next 24 hours. The exception being periods of MVFR/IFR conditions
generally associated with convection later this morning through the
afternoon. Shower convective activity will begin developing over inland
areas mid to late morning and continuing through the afternoon
timeframe. Some scattered thunderstorms also possible. Light to ocnly
moderate south to southwesterly surface winds today...except stronger
gusts and more variable directions in and near showers and
thunderstorms. Most convective activity should diminish shortly after
dark this evening...with light southerly winds becoming variable over
inland areas overnight. 12/DS

PREV DISCUSSION... /issued 438 AM CDT WED JUL 27 2016/ 

NEAR TERM /Now Through Wednesday night/...Weak trough of surface low
pressure oriented west-east along the Gulf coast dissipates as
surface high pressure ridge builds west across the area today and
then expands slightly north tonight. Aloft...high pressure centered
just off the southeast US Atlantic coast also ridges west over our
area. Gulf moisture continues to be lifted northward into the
forecast area on the western periphery of this ridging with
precipitable water values ranging from around 1.75 inches eastern
forecast zones to near 2.25 inches over western zones. With surface
trough dissipating and ridging building...expect rain chances to be
lower today than yesterday. But with the ridging greatest to the
east and the moisture highest to the west...still expect a good
chance for showers and storms today (especially over western half of
the forecast area). As has been the case lately...convection will
generally be diurnally driven...with best coverage this afternoon
then dissipating during the early evening hours with only a slight
chance of lingering showers overnight tonight. Still plenty of rain
and cloud cover...so daytime highs today similar to yesterday in the
upper 80s to lower 90s most locations (although a few mid 90s
possible in areas that receive less rainfall). Lows tonight again in
the low to mid 70s across the area...with the warmer temps at the
coast. 12/DS

SHORT TERM /Thursday Through Friday night/...The upper level trough
over the southern Mississippi River valley region bisecting the two
upper high pressure systems will persist through Thursday. This upper
level trough will then weaken slightly on Friday as the two high
pressure systems attempt to reconnect over the northern Gulf of
Mexico. Meanwhile a surface ridge will remain fixed across the
western Atlantic and eastern Gulf of Mexico keeping a light southerly
wind flow and low level moisture in place across the region. Still
expect isolated to low-end scattered coverage of showers and
thunderstorms to occur through the short term, forming mainly along
the sea-breeze both Thursday and Friday afternoons.

Temperatures will be near normal through the short term, with low
temperatures in the low to mid 70s inland areas, with upper 70s
along the coast. High temperatures will range from 90 to 95 degrees
with the exception of the upper 80s along the coast. Heat indices
will range from 100 to 105 degrees both days. /22

LONG TERM /Saturday Through Tuesday/...An elongated upper ridge will
extend from Southern California to the northern Gulf of Mexico and
out over the western Atlantic to start off the weekend. Meanwhile a
broad upper trough will stretch from the northern plains to the
northeast states with its base reaching as far south as the central
portions of Mississippi and Alabama. The base of the upper trough
will gradually loosen its grip across the region over the weekend as
the trough moves very slowly eastward, followed by upper heights
building in its wake across the central U.S. Monday and Tuesday.

With this said we still do not expect much change in the expected
weather conditions, with isolated to scattered showers and
thunderstorms persisting across the forecast area throughout the
long term. The convection will primarily be diurnally driven, so
expect the best chances to be during the day and early evening hours
followed by mainly dry conditions overnight.

Temperatures will also be persistent and near normal through the
remainder of the forecast, with low temperatures ranging from 73 to
77 degrees inland areas, with upper 70s along the coast. High
temperatures will range from 90 to 95 degrees with the exception of
the upper 80s along the coast. Heat indices will range from 100 to
105 degrees each day. /22

MARINE...A weak low pressure trough dissipates along the Gulf
coast today with high pressure building over the northern Gulf of
Mexico. A high pressure ridge then persists over the northern and
eastern Gulf through the upcoming weekend. Light to moderate south
to southwest winds this morning becoming light...with a light
onshore flow then persisting into the weekend. Seas subsiding
through today then generally 1 to 2 feet for the remainder of the
week. Winds and seas higher near scattered showers and
thunderstorms through the period. 12/DS

&&

.MOB Watches/Warnings/Advisories...
AL...High Rip Current Risk until 6 PM CDT this evening for ALZ265-266.

FL...High Rip Current Risk until 6 PM CDT this evening for FLZ202-204-
     206.

MS...None.
GM...None.
&&

$$

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