402 
FXUS64 KMOB 112351 AAA
AFDMOB

Area Forecast Discussion...UPDATED
National Weather Service Mobile AL
651 PM CDT Wed Aug 11 2021

.AVIATION...
00Z issuance...Isolated to scattered showers and storms located 
mainly well inland will diminish this evening, then redevelop
near the coast early tomorrow morning before spreading further
inland and increasing in coverage during the day. MVFR conditions
will accompany the stronger showers and storms while otherwise VFR
conditions prevail. Light and variable winds tonight become
southeasterly around 5 knots on Thursday. /29

&&

.PREV DISCUSSION... /issued 316 PM CDT Wed Aug 11 2021/ 

NEAR TERM UPDATE /Now Through Thursday/...A persistent mid to upper 
level ridge over the Southeast will dominate the pattern through 
Thursday as a weak upper level low meanders over the Florida 
peninsula. Down in the lower levels, the local area remains on the 
western periphery of a surface ridge over the western Atlantic 
through Thursday. The overall flow aloft and at the surface remains 
relatively weak in this pattern. Given no real forcing aloft, the 
main driver for the development of showers and storms continues to 
be the sea breeze and any colliding outflow boundaries. PWATs 
continue to rise with around 2.0+ inches along the coast this 
afternoon with slightly drier values north of the Highway 84 
corridor. Onshore flow remains in place on Thursday, allowing 
moisture to continually stream into the area during the day.

Scattered showers and storms will continue into the early evening 
hours with sufficient instability (MLCAPE of 2000+ J/kg) and several 
remnant outflow boundaries surging across the area. Convection will 
slowly diminish across inland areas this evening with the loss of 
daytime heating. Expect showers and storms to re-develop over the 
Gulf after midnight along the land breeze with storms firing up in 
the pre-dawn hours right along the coast. Storms will continue to 
develop along the sea breeze through the morning hours and spread 
inland through the day. The highest coverage will remain across the 
southern half of the area through the morning and early afternoon 
before transitioning inland by late afternoon. Similar to today, a 
few storms (wet microbursts) will be capable of producing gusty 
winds, although widespread severe weather is not anticipated. Given 
the high PWATs and weak flow aloft, a few storms will be capable of 
producing heavy rainfall with minor flooding issues possible this 
afternoon and Thursday, especially in urban areas and typical 
flood prone areas/trouble spots.

Heat stress remains a concern on Thursday. Temperatures this 
afternoon remain in the upper 80s to low 90s thanks to the coverage 
of showers and storms earlier today. Low temperatures continue to 
sound like broken record overnight as temperatures only fall into 
the mid to low 70s inland with upper 70s to near 80° at the beaches. 
Rinse and repeat for Thursday as highs rise into the mid to low 90s 
across the entire area thanks to the coverage of showers and storms. 
Dewpoints remain in the mid 70s inland (mixing out into the low 70s 
in the afternoon) with upper 70s at the beaches on Thursday. This 
combination will result in heat indices of 101-107° on Thursday, so 
a Heat Advisory will not be necessary.

Rip current risk remains LOW through the near term. 07/mb

SHORT TERM /Thursday night Through Saturday night/...
Synoptically, and through the period, the region remains in a 
weakness between two high pressure cells, one just off the Mid- 
Atlantic Coast and a second over the Plains. Very little change in
the surface mean seas level pressure field, as a result. The tail
end of the period (i.e., from midday Saturday on), will sees 
falling upper heights as Fred makes its move into the SE Gulf of 
Mexico). This weakness is associated with abundant deep layer 
moisture and lower overall static stabilities. Breaking it all 
down, it will be a wet period with rain chances running about 20%
above normal on average. There will still be a tendency to see
land breeze showers and thunderstorms over the water at night and
early morning reversing to being over land, and with inland
progression during the afternoon. We will mention that dry air 
aloft in the mid- and upper levels with allow afternoon 
thunderstorms to have near severe to locally severe downdraft 
potential, both Friday and Saturday afternoons. Heat indices 100 
to 106 degrees (perhaps 106-108 F in pockets) both afternoons. /23 JMM

EXTENDED TERM /Sunday Through Wednesday/...The main feature of 
concern continues to be Tropical Storm Fred, which is currently 
forecast to move into the SE Gulf of Mexico Saturday morning, to 
be then be located west of the central FL Peninsula by Sunday 
morning and then landfall somewhere across the FL Panhandle by 
early Monday morning. The track forecast continues to have quite a
bit of uncertainty with it - still, as the day 5 western edge of 
the cone ranges from being just east of Lake Pontchartrain on its 
western edge to near Jacksonville, FL on its eastern edge. So, we 
have some time, but NOW IS the time to be making preparedness 
plans in the event you have to enact them. The potential for wind 
impacts continues to increase during the past 24 hours, as there 
is now about a 1 in 10 chance of seeing 39 mph or higher west of 
I-65, ranging to nearly a 2 in 10 chance of experiencing the same 
near Destin. Also, the rip current risk will become HIGH over the 
weekend and remain so well into next week. The current earliest 
reasonable arrival time of tropical storm force winds would be 
Sunday morning east of Pensacola and along the coast, but most 
likely later in the day on Sunday. So, keep watching the trends 
and we'll keep breaking down the impacts in space and time. There 
are a lot of factors that will ultimately determine the precise 
path of the storm and future adjustments will be necessary. Given 
our current sensible weather forecast, on Sunday, showers and 
thunderstorms will advance into the region from the southeast on 
Fred's western periphery. Rain chances remain elevated Sunday 
Night, Monday, Tuesday and into Wednesday (with the highest 
chances being east of I-65 Corridor Monday and Tuesday) as Fred's 
moisture envelope continues to diminish in areal extent, but still
will be acting to increase rain chances over our region. High 
temperatures through the period will be most stunted east of the 
I-65 Corridor from Sunday on and will range from the lower 90s 
over interior SE MS to the upper 80s east of I-65. Overnight lows 
mainly in the 70s. /23 JMM

MARINE...No impacts expected through at least Saturday aside from 
higher winds and seas near scattered storms. We continue to monitor 
Tropical Storm Fred as it is forecast to enter the southeastern Gulf 
of Mexico on Saturday. This system will increase winds and waves 
on both Sunday into Monday. Refer to the official National 
Hurricane Center advisories for more information regarding Fred. 07/mb

&&

.MOB WATCHES/WARNINGS/ADVISORIES...
AL...None.
FL...None.
MS...None.
GM...None.
&&

$$

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