Area Forecast Discussion
Issued by NWS Mobile, AL

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FXUS64 KMOB 171142

Area Forecast Discussion
National Weather Service Mobile AL
642 AM CDT Tue Sep 17 2019

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


12Z issuance...VFR is expected to prevail across the region
through the next 24 hours. An isolated SHRA or TSRA will be
possible this afternoon, but probabilities are very low and have
not included mention in the local TAFs. Light northwest to north
winds will generally continue today, except becoming southwest
5-10 knots over southern portions of our area along a seabreeze
this afternoon. /21


.PREV DISCUSSION... /issued 440 AM CDT Tue Sep 17 2019/

NEAR TERM /Now Through Tuesday night/...A mid to upper level ridge
of high pressure will extend from the Lower Mississippi Valley to
the Great Lakes region today, while a broad low pressure system
slowly drifts across the northwestern Gulf of Mexico near the
southeast TX coast. Most of our forecast area will remain under the
influence of the building mid to upper level ridge today, with
associated subsidence and rather low precipitable water values
between 1.2 and 1.4 inches. We will keep a mostly sunny and dry
forecast intact across most inland areas today. The exception could
be across southern portions of southeast MS and far southwest AL,
where low level convergence along a developing seabreeze, higher
precipitable water values between 1.6 and 1.9 inches and associated
higher instability may result in the development of a few isolated
showers and thunderstorms this afternoon. We will opt to include a
15-20% POP in the forecast generally southwest of a Janice, MS to
Mobile, AL line this afternoon. The heat will otherwise persist
across the area today with high temperatures forecast to range in
the mid to upper 90s, with a few locations reaching around 100
degrees. These readings could approach record levels (record high
temperatures for today include 100 degrees at KMOB set in 1927 and
97 at KPNS set in 1991). Mostly clear and dry conditions are
anticipated tonight with lows around 70 degrees to the lower 70s
inland, and in the mid to upper 70s near the coast and beaches.

SHORT TERM /Wednesday Through Thursday night/...An upper ridge
will remain in place through the period. This will bring another
day of hot and dry weather to the area on Wednesday with temps in
the upper 90s to near 100. The sfc ridge builds across the mid-
Atlantic coast into the southeast during the latter half of the
week. This will bring an easterly flow to the area as a back- door
cold front moves through the area on Thursday and brings a slight
decrease to the hot temps. This feature will also produce
isolated to scattered showers and storms to the area on Thursday.

LONG TERM /Friday Through Monday/...Deep layer ridging continues
across the area through Saturday before flattening out somewhat
Sunday into Monday as an upper trough moves across the Great Lakes
region. An associated weak front will approach the Tennessee
Valley but stall north and west of there due to the ridge over the
southeast. Therefore rain chances remain low through the period
outside of small chances near the coast and offshore.
Temperatures remain in the low to mid 90s each afternoon. /13

MARINE...A weak surface ridge of high pressure will remain in place
over the north central Gulf of Mexico through Wednesday night. A
light north to northwest flow late at night and in the morning will
become light to occasionally moderate southwest in the afternoon and
evening today through Wednesday night. A strong surface ridge of
high pressure will build from the eastern and southeastern states
and into the northeastern Gulf of Mexico Thursday through the
weekend. This pattern will result in a moderate to occasionally
strong easterly flow and building seas across the marine area late
this week and into much of the weekend. /21




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