Area Forecast Discussion
Issued by NWS Mobile, AL

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FXUS64 KMOB 271140

Area Forecast Discussion
National Weather Service Mobile AL
640 AM CDT TUE SEP 27 2016

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


12Z issuance...Patchy MVFR to IFR fog, with some very localized LIFR
visibility reductions will impact a few locations through around
27.13-14Z, mainly over southwest/south central AL and interior
northwest FL. VFR is otherwise expected to prevail around the region.
Isolated to scattered SHRA/TSRA are expected to develop again this
afternoon. /21


.PREV DISCUSSION... /issued 444 AM CDT TUE SEP 27 2016/

NEAR TERM /Now Through Tuesday night/...A weak flow pattern aloft
is in place across the central Gulf Coast region early this morning
to the west of a weak upper trough over north central FL and well to
the south of a deep upper level low and associated trough over the
Great Lakes region. Early morning surface analysis shows a weak cold
front stretching across southeast LA and MS and northeastward
through central portions of AL. There is some increased mid and
upper cloud cover over western and northern portions of the forecast
area early this morning, but mostly clear skies and moist conditions
have favored development of some patchy fog over portions of south
central AL and the northwest FL Panhandle over the past couple of
hours. High resolution guidance continues to trend at potential for
some locally dense fog for a few hours early this morning north and
east of a Crestview, Bay Minette, Grove Hill line and will continue
to monitor trends closely.

A west to northwest flow pattern aloft will prevail across the
region through tonight as the upper level low digs southward over
the Great Lakes and the broad upper trough deepens over much of the
eastern CONUS. The frontal boundary will move little and will become
oriented over southeast MS and interior southwest AL this afternoon.
A moist and somewhat unstable airmass will be in place along and
ahead of the boundary this afternoon, with precipitable water values
generally averaging between 1.75 and 2.0 inches and MLCAPE of 1000-
1500 J/KG. Isolated showers and storms starting off mainly near the
coast during the morning should become more scattered in coverage
across much of the region by this afternoon, and will carry 30-40%
POPs in the forecast across most locations. Convective coverage
should decrease this evening, but will still keep a slight chance in
the forecast over most areas through the evening with moisture still
in place ahead of the lingering boundary. High temperatures today
are forecast to remain above normal, with readings in the mid to
upper 80s near the immediate coast to around 90 inland.  The front
should continue to sag farther south and east across the forecast
area tonight, with light northwest winds bringing a drier airmass
and surface dewpoints in the 50s over southeast MS and interior
southwest AL late. Lows tonight should subsequently range in the
lower to mid 60s over northwestern portions of the area to the upper
60s to lower 70s east and south. /21

SHORT TERM /Wednesday Through Thursday night/...The cold front will
move south of the area through the day on Wednesday with a much
drier airmass moving into the area. A reinforcing cold front moves
through the area on Thursday bringing cooler air to the region.
Precipitable water values drop to 0.5 inches by Wednesday evening as
a deep upper level trof develops over the eastern states. This will
maintain a dry north to northwest wind deep layer wind flow. After a
slight chance of rain near the coast Wed morning, dry conditions will
prevail through the remainder of the period with much lower humidity.

Highs will be in the mid and upper 80s on Wednesday before dropping
to upper 70s inland to mid 80s along the coast Thursday. Lows
Wednesday night fall into the upper 50s and low 60s inland to near
70 along the coast. Thursday night low will be in the mid 50s inland
to low 60s along the coast. /13

LONG TERM /Friday Through Monday/...The large upper low over the
eastern states shifts northward slowly through the weekend before
ejecting northeast early next week. A deep layer northerly flow
continues over the area through the period as a surface ridge builds
into the eastern states. This will maintain dry conditions through
Monday. Highs will be around 80 on Friday before moderating into the
mid and upper 80s by Monday. Lows Friday night will be in the mid 50s
inland to low 60 along the coast before moderating through next week
as moisture levels slowly increase. /13

MARINE...A weak ridge of high pressure will remain in place over
the southeast states through Wednesday. A light wind flow pattern
prevails through tonight, before light to moderate westerly to
northwesterly flow returns Wednesday and Wednesday night. A cold
front will move across the marine area early Thursday morning, with
increasing offshore flow expected, especially Thursday night and
Friday morning, when wind speeds could range in cautionary levels.
Light offshore flow should otherwise prevail into the weekend. /21


.MOB Watches/Warnings/Advisories...


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