Area Forecast Discussion
Issued by NWS Mobile, AL

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FXUS64 KMOB 231737 AAA

Area Forecast Discussion...UPDATED
National Weather Service Mobile AL
1237 PM CDT Fri Aug 23 2019

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


18Z issuance... VFR conditions will prevail through much of the
period. Brief periods of IFR/MVFR conditions are possible in and
around SHRA/TSRA. /13


.PREV DISCUSSION... /issued 451 AM CDT Fri Aug 23 2019/

NEAR TERM /Now Through Friday night/...Weak mid/upper ridging
over the area today will weaken further tonight as it will be
influenced by two developing mid/upper level low pressure areas,
one over the western Gulf and the other over the Bahamas. At the
surface, weak high pressure continues along the Gulf coast and
over the eastern Gulf of Mexico, while a weak trof or frontal
boundary continues well north of the area over extreme northern
Alabama and Tennessee. Deeper layer moisture will continue to be
pooled south of the surface boundary, with PWATS in the 1.9 to 2.2
inch range through the near term. The moist atmosphere, when
combined with daytime heating and instability, will continue to
support a diurnal convective pattern with mostly afternoon and
evening showers and storms. A few storms could be briefly strong
this afternoon, but the more likely threat will be localized heavy
rainfall. Highs today expected to be in the upper 80s and lower
90s. Lows tonight in the lower 70s most areas except along the
coast where mid to upper 70s are expected. 12/DS

SHORT TERM /Saturday Through Sunday night/...The base of an upper
trof is in place over the deep south Saturday with a slightly
sharper presentation of the trof evolving on Sunday. Deepest Gulf
moisture streams north and eastward out of the western Gulf up
into the southeast through the weekend. Considering moisture
availability, daily instability, mid-level impulses and interactions
of convective outflow boundaries in the mesoscale favor scattered
to perhaps numerous convective coverages each day. Storms could
be strong at times, producing brief strong wind gusts, frequent
lightning and locally heavy rains which can fall over a short time
span. At the surface, a weak pressure pattern results in light
winds which take on a southerly direction each day, especially
closer to the coast.

Daily highs range from the upper 80s to lower 90s. Highest heat
indices near 105 closer to area rivers. Overnight lows in the
70s. /10

LONG TERM /Monday Through Thursday/...Upper trof axis from the
upper Mid-West southward to the central Gulf coast Monday morning
eases eastward over the southeast US by the middle of the week
allowing for a slow southward advance of a frontal boundary.
With respect to deep moisture, PWATs range from 1.8 to 2.1 inches
over the local area. See no reason to deviate from modest daily
PoPs through the mid-week time frame. By Thursday, the 23.00Z
ECMWF suggests a drier deep layer environment will overspread the
area while the GFS continues to remain unsettled. Considering
these differences, will maintain lower end chance of showers and
storms Thursday. /10

MARINE...A light and predominately onshore wind flow will continue
today and tonight, becoming more variable and at times light
offshore over the weekend before becoming mostly light to moderate
onshore again by early next week. Seas will range between one and
two feet outside of scattered late night and early morning shower
and thunderstorm activity. 12/DS




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