386 
FXUS64 KMOB 141742
AFDMOB

Area Forecast Discussion
National Weather Service Mobile AL
1242 PM CDT Fri Aug 14 2020

.NEAR TERM /Now Through Saturday/...Will start the near term 
period with a weakness in the geo-potential height aloft 
characterized by a broad synoptic scale trough draped from the OH 
River Valley to the central Gulf coast. Embedded in the mean 
northwesterly flow aloft between the trough and the nose of a deep
layer ridge over TX, satellite shows a notable area of cold cloud
tops/enhanced lightning dropping southeast into the MS Valley of 
eastern AR/northwest MS. The evolution of this feature is of 
primary concern in the very near term. Ahead of the complex, an 
assessment of environmental moisture is primed for convective 
support/maintenance with PWAT values 1.9 to 2.2 inches. These 
values stand some 110 to 120% of normal when comparing to 
climatology. The local air-mass is unstable with MUCAPE values on 
the order of ~2500 J/Kg on average. Shear is weak at present ahead
of the southeastward moving complex, with the better values 
displaced to its west over northern LA to across the Red River 
Valley of TX/OK. However, a modest increase in vertical shear is 
possible going into the remainder of the day as mid level impulse 
/short-wave trough moves across the deep south. Also, with a 
favorable pre-storm environment of moisture and instability, the 
HRRR/WRF ARW is showing a well defined linear convective line 
developing and moving southeast across southeast MS this afternoon
and moving to the coast by evening. Forecasters are beginning to
see this in radar trends upstream. To aid in ascent is the 
presence of a broad surface pressure trough along the I-65 
corridor. A marginal risk of severe storms is updated to now 
include southern MS to southwest AL through 7 PM this evening. 
Torrential downpours will also accompany the stronger convection 
and this could lead to some localized, minor flooding issues. Will
carry the likelihood of convection spreading east southeast this 
evening with some decrease in coverage noted by the middle of the 
evening. While convection typically diminishes late in the evening
into the overnight hours this time of year, the presence of the 
shortwave trough atop the area will serve to keep at least 
isolated to scattered storms going through a good portion of the 
night. There are indications that an enhanced coverage of storms 
will be likely along the immediate coast and offshore during the 
overnight/pre dawn hours. 

Scattered to numerous storms are expected to continue into Saturday 
morning, however there is likely to be some decrease in coverage 
over inland SE MS/SW AL by the afternoon as the shortwave trough 
begins to move east and drier air starts to move into the area. 

The greater coverage in clouds and precipitation will tend to 
keep highs in check, mostly in the upper 80s to near 90 Saturday.
Lows remain in the 70s, typical for this time of year. /10

&&

.AVIATION...
18Z issuance...Afternoon convection is beginning to increase
initially east of I-65 and westward with a complex migrating
southeast over central MS. Storm coverage will continue to
increase during the heat and instability of the day. Main impacts
to approaches and departures will be brief strong and variable 
convective wind gusts in and near storms, visibility reduced in
heavier downpours and frequent lightning activity. A more solid
line of storms is expected to drop southeast through southeast MS
this afternoon and near the coast by this evening. Cigs lower to
MVFR categories with scattered lower bases to IFR possible. Vsby 
may be reduced briefly to LIFR/IFR categories in +TSRA. A few of 
the storms could become severe. /10

&&

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

$$

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