Area Forecast Discussion
Issued by NWS Mobile, AL

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FXUS64 KMOB 272330 AAA

Area Forecast Discussion...UPDATED
National Weather Service Mobile AL
630 PM CDT Sat May 27 2017

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


00Z issuance...Persistence type pattern continues tonight with
high pressure over the eastern Gulf supporting the reformation of
low stratus by and after 28.03Z. Cigs potentially lowering to IFR
categories late. South to southwest winds generally 5 to 10 kts.


.PREV DISCUSSION... /issued 325 PM CDT Sat May 27 2017/

NEAR TERM /Now Through Sunday/...Isolated areas of light
precipitation and low clouds earlier today continue to erode as
boundary layer conditions become better mixed mostly from daytime
heating and afternoon seabreeze circulations. For early this
evening, expect a mix of low to mid clouds before sunset followed
by increasing clouds overnight through Sunday morning as better
moisture continues to become trapped below a capping inversion
that forms later this evening continuing through most of Sunday
morning, similar to today. Latest model soundings support this
reasoning with a warm nose (4-10 kft)lowering to 2-10 kft later
this evening continuing over all areas in the forecast area
through mid-morning Sunday, then gradually lifting once again through
Sunday afternoon. So, expect a very similar pattern on Sunday
with maybe a few sprinkles, or very light showers, early in the
morning but eroding during the afternoon. As for temps with the
continued onshore flow across the region, lows tonight will run
3-5 degrees above seasonal averages, ranging from the lower 70s
for most inland areas and the middle 70s near the immediate coast.
Highs Sunday will be near seasonal averages, ranging from upper
80s to near 90 for most inland areas and the middle 80s along the
immediate coast. /32 EE

SHORT TERM /Sunday night Through Tuesday night/...By Sunday night,rain
chances increase from the west and this continues through Monday
afternoon in response to the next approaching upper trough and an associated
weakening low level frontal boundary. The weak front will move
into northern sections of the forecast area by late Monday
afternoon and this will become the main focus for the heavier
precipitation later on Monday. We are forecasting a decent
coverage near the coast and offshore early Monday, mostly where
the better surface based instability will be early, combined with
limiting capping in the boundary layer. On Monday afternoon,
SBCAPEs range from 2200-2600 j/kg combined with the weak front at the
surface and weak forcing aloft (still less than impressive). Given
this, a few strong storms will be possible, mostly in areas of
stronger daytime heating  better instability and occurring
mostly over the middle and northern sections of the forecast
Monday afternoon. At this time gusty straight line winds, frequent
cloud to ground lightning and periods of heavy rain, possibly
leading to some nuisance localized flooding are the main impacts. Precipitation
coverage slowly decreases during the evening. Tuesday has now trended
wetter overall and the aforementioned weakening cold front will
still be around to serve as a focal point for convective initiation
(albeit, coverage will be less). Raised rain chances Tuesday and
into early Tuesday evening. Another piece of shortwave energy
rounds the base of Ohio Valley trough and sends another deep-
layer moisture band southward into our area by sunrise Wednesday. This
will keep low end rain chances around Tuesday night. /32 EE and
/23 JMM

LONG TERM /Wednesday Through Saturday/...Similar to its` Monday
cold front predecessor, the boundary becomes diffuse during the
day on Wednesday and weakening surface high pressure tries to
build at base of upper trough across our region. Despite this, the
boundary will serve as a focal point for scattered afternoon
showers and thunderstorms in seemingly more of a diurnal regime.
For the period Thursday through Friday, it would be a forecast of
persistence as region remains on SW periphery of SW Atlantic
ridge. Boundary layer flow remains southerly with scattered
showers and thunderstorms both days. Saturday looks slightly drier
at this point as a deeper ridge builds over region (but this is
currently forecast to be short-lived). Significant deep-layer
moistening from the west is forecast later in the weekend. Highs
in the mid to upper 80s each day with overnight lows in the upper
60s (inland) to mid 70s (beaches). /23 JMM

MARINE...A light to moderate south to southwest wind flow will
continue through Monday as high pressure slowly shifts east of
the area. A weak frontal boundary will stall near the coast Monday
night into Tuesday leading to a decrease in winds and seas
through midweek. More shower and thunderstorm coverage can be
expected early in the week as the front nears. A better onshore
flow returns later in the week. No small craft advisories expected
either due to winds or seas during the upcoming forecast period.
Seas remain 2-3 feet tonight through Tuesday, then decrease to 1-2
feet (or less at night) as the front stalls. /23 JMM




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