Special Weather Statement, NWS Mobile, AL

Area Forecast Discussion
National Weather Service Mobile AL
402 PM CDT Wed Aug 15 2018

.NEAR TERM /Now Through Thursday/...A well defined coastal sea-
breeze boundary was positioned from southern MS eastward to across
northwest FL. Along the boundary, scattered showers and storms
have developed in a deeply moist and unstable environment. Aloft,
the deep layer ridge off the LA coast has broken down a bit as
lower H50 geo-potential heights ease eastward out of the Plains,
associated with next upstream trof. A small chance of storms will be
maintained into the first half of period one to account for showers
and storms that carry over into the evening before weakening.
Potential also exists for the formation of patchy late night fog.

For Thursday, latest physicals show an evolving, albeit subtle break
in the mid level sub-tropical ridge to become positioned over the
local area. Meanwhile, a surface ridge builds west from the western
Atlantic into the eastern Gulf, which will maintain a persistent,
moist onshore flow. With a weaker reflection in the high level ridge
Thursday, combined with persistent deep layer moisture, daytime
heating (resultant increase in instability) and weak sea-
breeze/mesoscale boundaries to provide a focus, scattered to perhaps
numerous storms anticipated. A few storms potentially strong,
producing brief strong convective downbursts, frequent lightning and
locally heavy rains. /10

.SHORT TERM /Thursday night Through Saturday night/...Convection
will gradually taper off Thursday evening as the boundary layer
becomes increasingly stable. A moist onshore flow will keep
overnight humidity up and overnight lows will only drop into the
mid 70s near the coast and low to mid 70s inland.

Shortwave energy aloft, currently over the northern great plain
states, will propagate eastward carving out an upper trough over
the eastern states. The north central Gulf region will fall under
the southern periphery of the trough, and although most of the
dynamics will remain north of the area, the added weak upper
level forcing coupled with the persistent deep layer moisture,
afternoon instability and mesoscale surface boundaries should
create an uptick in showers and thunderstorms Friday and Saturday.
At this time the strongest storms are expected to produce
frequent cloud to ground lightning, brief heavy rainfalls and wind
gusts in the 35 to 45 mph range.

.LONG TERM /Sunday Through Wednesday/...Latest model runs depict
the upper trough over the eastern states filling by Sunday with a
weak upper level ridge developing. The associated weak large scale
upper level subsidence is unlikely to shut down afternoon
convection that will take advantage of the ample afternoon
instability, deep layer moisture pool overlying the area and
firing off the sea breeze front and other lingering outflow
boundaries. Minor shortwaves rippling through the relatively flat
flow aloft will also assist. On the upside, expect the convective
coverage to be less and be more scattered than numerous. The weak
upper level ridge is projected to remain over the area through at
least Tuesday with scattered thunderstorms developing each
afternoon and gradually dissipating during the evening hours. An
increase in thunderstorm activity is possible again on Wednesday
as some of the model runs project another surge of upper level
shortwave energy carving out another trough over the eastern
states. Have kept convection scattered for now but may have to
increase POPs if we get some run to run model consistency. /08

&&

.MARINE...Very little change with respect to the position of a
synoptic scale surface high over the western Atlantic, which noses
westward across the Gulf. This feature maintains a prevailing south
to southwest flow through the period. Seas 1 to 2 feet early in the
period hold steady closer to 2 feet Friday, continuing into the
weekend. Winds, waves and seas locally higher in and near storms.
/10

&&

.PRELIMINARY POINT TEMPS/POPS...
Mobile      73  91  74  91  74  90  74  90 /  20  60  20  60  30  60  30  50
Pensacola   76  88  76  89  76  89  77  88 /  20  60  30  40  30  60  30  50
Destin      78  86  78  87  78  87  78  86 /  30  60  30  40  30  60  30  50
Evergreen   73  90  73  91  73  90  74  90 /  10  60  20  60  30  60  30  50
Waynesboro  72  92  72  91  72  90  72  90 /  10  60  20  40  30  60  30  50
Camden      73  91  73  91  73  90  74  90 /  10  50  20  50  30  60  30  50
Crestview   73  88  73  90  74  89  74  89 /  30  70  20  60  30  60  30  50

&&

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

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