Area Forecast Discussion
Issued by NWS Mobile, AL

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337
FXUS64 KMOB 251828
AFDMOB

Area Forecast Discussion
National Weather Service Mobile AL
128 PM CDT THU AUG 25 2016

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

&&

.AVIATION...
25/18Z issuance...Isolated to scattered convection this afternoon and
early evening...mainly over the western zones and down along the
coast (especially from MOB and BFM westward). Only VCTS mentioned for
those two locations for this afternoon as coverage very isolated thus
far. Resultant VFR conditions expected. Light mostly east winds thru
this afternoon...becoming light and variable overnight except at the
coast where light easterly flow continues into Friday. 12/DS

&&

.PREV DISCUSSION... /issued 637 AM CDT THU AUG 25 2016/

DISCUSSION...Updated for latest aviation discussion below.

AVIATION...
12Z issuance...Starting off the morning with patchy LIFR/IFR cigs and
VSBY`s. Low clouds and fog will quickly burn off after sunrise.
Satellite shows an area of mainly mid level cigs (bases > 5000 feet)
moving in from the east over interior. Isolated to scattered mid
morning to early afternoon convection possible mainly over the
western zones which could be close to MOB and BFM. Confidence too low
to mention in the TAF`s. As drier deep layer air-mass filters in from
the east by late afternoon and evening, the result is vfr conditions.
Light northeast winds this AM become east thru the day. /10

PREV DISCUSSION... /issued 440 AM CDT THU AUG 25 2016/

NEAR TERM /Now Through Thursday night/...Upper air analysis this
morning shows a deep layer ridge axis centered over northern MS/northern
AL with the east and west flank of the ridge stretching to off the
Mid-Atlantic coast to the eastern half of TX, respectively. On the
south and southwest periphery of the high level ridge, Water vapor
satellite imagery shows moisture streaming westward across the Gulf
and rotating anti-cyclonically up across the ARK-LA-TX. Initially,
highest deep layer moisture (pwats around 1.8 to 2 inches) is
aligned over the western zones today. This zone of moisture, when
coupled with daytime instability and the westward passage of subtle
mid level impulses results in isolated to scattered storm coverages
by mid morning into early afternoon generally along and west of a
line from Grove Hill AL to Pensacola FL. With the latest RAP and NAM
guidance showing most unstable convective potential energy (MUCAPE)
lifting up to between 2500 and 3500 J/kg over the western zones thru
the morning and into the afternoon, some storms could be locally
strong. Main threats in storms will be brief strong wind gusts in
excess of 40 mph, locally heavy rains, and frequent lightning. To the
northeast, vapor imagery is showing drier air over the southern
Appalachians where pwats are around 1.2 inches over the Carolinas.
This zone of drier air is forecast to advance westward through the
course of the day over the local area with minimal chances of
showers and storms over the eastern half of the area and coverages
lowering to isolated by late afternoon in the western zones.

Surface high pressure to the north and east of the local area
maintains a light easterly component of flow today, becoming more
northeast thru the night. Highs today forecast in the mid 90`s
interior to 88 to 92 at the beaches. Overnight lows in the lower
70`s interior to the mid to upper 70`s closer to the coast. /10

SHORT TERM /Friday Through Saturday night/...High pressure
currently centered over the interior southeastern United States will
drift northeast through the period before settling over the central
east coast by Sunday. While a surface ridge over the southeast is
generally progged to weaken into the weekend, should maintain enough
deep easterly flow to help usher in some drier air Friday and
Saturday, with PWATs expected to drop to around 1.2-1.5 inches. As a
result, shower and thunderstorm activity is expected to decrease into
the early weekend. Any isolated convective activity that does occur
will be limited to coastal and offshore regions, where deeper
moisture will be more likely to reside. Have thus left in slight
chance and chance POPs Friday and Saturday, respectively, for
offshore coastal waters and coastal regions. Afternoon highs both
Friday and Saturday expected to range from near 90 along the coast to
mid 90`s inland. Overnight lows will remain in the upper 70`s along
the coast to low to mid 70`s inland Friday and Saturday nights. /49

LONG TERM /Sunday Through Wednesday/...Long term forecast remains
uncertain, as it still largely depends on potential tropical
development of Invest 99L, which is currently located just northwest
of Puerto Rico. While current guidance suggests the disturbance will
continue to move northwest towards the Bahamas into the early
weekend, solutions regarding track and intensity diverge wildly
beyond that point as it remains largely uncertain whether the
northern Gulf coast region will or will not be impacted by any future
development. All interests in the area should continue to closely
monitor this situation and not focus on any individual model
solutions, as these will continue to vary greatly until/if a system
eventually forms. Please see the National Hurricane Center website at
http://www.nhc.noaa.gov and our website at http://weather.gov/mob for
the latest official information regarding this system.

With such great uncertainty remaining in the long range forecast,
have decided to keep chance to good POPs from Sunday through the
middle of next week, with the highest chances remaining largely
offshore and along coastal regions. Please continue to monitor the
forecast through the weekend, as these may and likely will change as
the situation continues to unfold and confidence grows in a
particular solution.

Highs in the low to mid 90`s expected to continue into Sunday before
tapering off some into the upper 80`s the remainder of the forecast
period. Expect overnight lows generally ranging from upper 70`s near
the coast to low to mid 70`s inland through the forecast period. /49

MARINE...Surface high pressure persists from the Mid-Atlantic into
the southeast over the next several days resulting in an easterly
component of flow over the coastal waters. Little change in seas (2
to 4 feet) is expected through Sun. Easterly fetch is forecast to
begin increasing and seas trend slightly higher well offshore early
next week as low pressure possibly moves into the eastern Gulf. Winds,
waves and seas will be locally higher in and near storms. /10

&&

.MOB Watches/Warnings/Advisories...
AL...None.
FL...None.
MS...None.
GM...None.
&&

$$

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