Area Forecast Discussion
Issued by NWS Mobile, AL

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FXUS64 KMOB 260450
AFDMOB

Area Forecast Discussion
National Weather Service Mobile AL
1150 PM CDT Mon Sep 25 2017

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

&&

.AVIATION...
06Z issuance...VFR conditions are expected to remain prevalent
across the region through the forecast period. Exceptions could be
brief patchy fog and associated visibility drops to MVFR to IFR
levels overnight through early Tuesday morning in a few locations,
and also localized MVFR or lower conditions near isolated to
scattered SHRA/TSRA that will develop again Tuesday afternoon. The
best chance of convection Tuesday will be across southeast MS and
adjacent southwest AL. /21

&&

.PREV DISCUSSION... /issued 1005 PM CDT Mon Sep 25 2017/

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

UPDATE...Convection has come to an end over inland portions of
the forecast area this evening and we have updated the forecast to
remove POPs across all but coastal portions of southwest Alabama
and a very small portion of coastal northwest Florida overnight.
No other changes currently needed. /21

PREV DISCUSSION... /issued 629 PM CDT Mon Sep 25 2017/

DISCUSSION...Updated for latest aviation discussion below.

AVIATION...
00Z issuance...VFR CIGs/VISBYs expected through the forecast.
Local drops to MVFR levels likely in the rapidly decreasing
activity currently over the area, and with more activity expected
closer to the coast Tuesday.

/16

PREV DISCUSSION... /issued 348 PM CDT Mon Sep 25 2017/

NEAR TERM /Now Through Tuesday/...A weak upper level low
pressure area centered over southeast Mississippi will drift
south-southeast and begin to dissipate as a weak upper level
ridge begins to build west of the low. A surface ridge of high
pressure over the eastern conus and northeast Gulf of Mexico will
gradually weaken through Tuesday afternoon as Hurricane Maria
continues to the move slowly northward over the western Atlantic.
This pattern will keep a light easterly surface wind flow and low
level moisture across the area, with skies generally partly cloudy
to occasionally mostly cloudy.

The ongoing isolated to scattered showers and a few thunderstorms
will dissipate through mid evening with loss of daytime surface
heating, with the activity shifting back over the gulf waters
through the remainder of the night. Isolated showers to scattered
and thunderstorms are expected to re-develop after mid Tuesday
morning southwest of a line from Butler AL to Navarre Beach FL
(closer to the upper low) due to decreasing stability.

Low temperatures tonight will range from 66 to 69 degrees inland
areas, with low 70s along the immediate coastal sections. High
temperatures Tuesday will be 2 to 6 degrees above normal, ranging
from 88 to 92 degrees inland areas, with mid 80s along the
immediate coastal sections. /22

SHORT TERM /Tuesday night Through Thursday night/...Upper low
over the eastern Gulf moves little through the short term as an
upper ridge builds from the western Gulf into the Tennessee
Valley, pinching it off once again from the primary flow.
Expecting local area to remain rain-free Wednesday and Thursday
given PWATs dropping back to below 1.5 inches and subsidence
strengthening aloft as the upper trough axis sags south over
AL/GA. Meanwhile, a deep upper trough over the western CONUS
shifts east over the Great Lakes, pushing a weak front down into
the local area late Thursday into Friday. With front weakening as
it approaches and the relatively dry air in place ahead of it, not
expecting much in terms of rain, with no mention of it in the
forecast through Thursday night. High temps Wednesday and Thursday
remain 6 to 8 degrees above seasonal, reaching the low 90`s
across the area each afternoon. Low temps each night through the
short term range from mid 60s inland to low 70s at the coast. /49

LONG TERM /Friday Through Monday/...Weak frontal boundary stays
put along the coast or just offshore Friday night before surface
high pressure building over the eastern seaboard and Appalachians
shifts the local flow from northerly to easterly. With this shift,
a deeper plume of moisture passes briefly through the area
Saturday/Sunday, resulting in a slight bump in precip chances
across the area. This plume quickly moves off to the west and is
replaced by drier air Monday, with best precip chances remaining
offshore heading into early next week.

What the front lacks in rain, it also lacks in cool air. That
said, we will see temperatures dip from above seasonal (where
they`ve been) down to around seasonal Friday through the weekend.
Highs reach the low to mid 80s each afternoon and lows range from
low 60s inland to upper 60s along the coast each night. /49

MARINE...High pressure ridging into the marine area from the
northeast will continue through early Wednesday, but begin to
break down during the middle part of the week as a cold front
approaches from the northwest. The front will likely drift south
over the coastal waters late in the week. Scattered to numerous
showers and a few thunderstorms over the marine area today and
tonight, decreasing in coverage mid week, before increasing once
again late in the week. /22

&&

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

$$

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