FXUS64 KMOB 161747 AAB

Area Forecast Discussion...UPDATED
National Weather Service Mobile AL
1147 AM CST Sun Dec 16 2018

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


18Z issuance...Low clouds will continue to scattered out through
the afternoon hours with VFR conditions expected by 20Z-21Z.
Patchy fog is expected to develop tonight with MVFR/IFR conditions
possible. VFR conditions return by 17.15Z. /13


PREV DISCUSSION... /issued 446 AM CST Sun Dec 16 2018/

NEAR TERM /Now Through Sunday night/...The deep area of low
pressure that has brought persistent low clouds to the Central
Gulf Coast region for the last few days will continue to shift
northeast reaching the Mid Atlantic coast by early this afternoon,
then moving well off the New England coast by 12z Mon. In the
wake of this system a weaker short wave trof will move southeast
from the Central Plains States to the North Central Gulf region
today and tonight, this pattern will lead to better sunshine for
most locations in the forecast area by this afternoon, followed by
more low to mid clouds moving across most locations this evening
and overnight. With limited moisture in the boundary no rain is
expected today and tonight. Some of the medium range guidance does
show some fog developing late tonight and early Mon with the best
coverage occurring over most inland areas of Southeast MS
stretching east into parts of inland Southwest AL.

With less clouds expected later today temperatures will warm to
near seasonal levels by this afternoon and continue near seasonal
levels through tonight. Highs today will range from the upper 50s to
lower 60s for most locations today. Lows tonight will range from the
lower 40s generally along and north of the I-10 corridor and the
middle 40s to lower 50s further south to the immediate coast.

SHORT TERM /Monday Through Tuesday night/...Dry zonal flow aloft
continues into Monday morning, followed by a building shortwave
ridge over our area Monday afternoon into Monday night. Dry
weather will continue underneath this pattern and will keep POPs
nil. A surface ridge of high pressure will build eastward across
the Mississippi and Tennessee Valley and adjacent central Gulf
Coast through Monday night, resulting in light northwesterly to
northerly flow over our region. High temperatures on Monday are
expected to be slightly warmer with readings in the lower to mid
60s. Lows Monday night will be seasonably cool, ranging from
the upper 30s to lower 40s over interior areas, and in the mid to
upper 40s near the immediate coast and beaches.

The next upper level trough is forecast to move across the Rocky
Mountains and the adjacent Plains states on Tuesday. Mid level
flow will transition southwesterly across our forecast area in
advance of this system during the day Tuesday, but a very dry
airmass will remain in place over our area with precipitable water
values remaining around 0.50", so no rain is expected. High
temperatures should continue to range in the lower to mid 60s,
with overnight lows Tuesday night in the 40s over most areas. /21

LONG TERM /Wednesday Through Saturday/...The upper level trough
is forecast to deepen as it progresses from the Plains states to
the Mississippi Valley region Wednesday into Wednesday night. Deep
layer moisture and ascent increases from west to east across our
forecast area during the day Wednesday, and expect scattered to
locally numerous rain showers to develop over the region through
the day. The best coverage currently looks to be focused over our
central and western zones where POPs have been increased to 40-60%
by Wednesday afternoon. Higher rain chances should spread east
across our region into Wednesday night, and will continue to
carry likely POPs over the central and eastern CWA. There may be
enough instability for isolated thunderstorms, mainly over our
southern zones. An upper level low may deepen somewhere in the
vicinity of Mississippi and Alabama Thursday and Thursday night,
and will keep rain chances in the forecast as this feature moves
across our region. POPs could linger into Friday depending on how
quickly the system gets a push east of our region. We will keep a
slight chance of rain in the forecast over central and eastern
areas on Friday for now. A tightening pressure gradient behind
the passing cold front may bring windy conditions to our area late
Thursday into Friday. Cooler temperatures return Friday behind
the front, with dry weather currently anticipated on Saturday with
slightly warmer temperatures. /21

MARINE...High pressure will build eastward over the northern
Gulf through Tue then shift further east later in the week in
response to a strong cold front approaching from the west. A light
northerly wind flow is expected through early Tue. A light to
moderate southerly wind flow is expected ahead of the front late Tue
through Wed night. A strong west to northwest flow is expected in
the wake of the front Thu through Fri. Seas are expected to build to
7 to 11 ft well offshore in the wake of the front by Thu night.
Better rain chances are expected ahead and along the front Wed
through Thu. 32/ee




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