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Area forecast discussion 
National Weather Service Mobile Alabama
624 PM CST Sat Feb 13 2016

Discussion...updated for latest aviation discussion below.


14/06z issuance...VFR conditions through 15.00z. Winds will be light
northeasterly 5 to 10 knots tonight...becoming more easterly during
the morning Sunday and then southeasterly (around 10 knots...slightly
higher at the coast) during the afternoon on Sunday as a surface high
pressure ridge axis shift east of the region. Mainly only high cirrus
clouds expected through the period...primarily by late Sunday. 12/ds


Previous discussion... /issued 405 PM CST Sat Feb 13 2016/

Near term /now through Sunday/...a strong surface ridge of high
pressure has pushed south and east over the much of the Mississippi
River valley and central Gulf Coast region this afternoon. Further
west a weakening upper ridge over Texas and the Lower Plains states will
shift eastward and continue to weaken leading to mostly a zonal flow
in the middle to upper levels across the deep south late tonight through
Sun afternoon. Further west a developing middle level shortwave will
also approach from the west late sun into Monday leading to increasing
middle to upper clouds for most of the western half of the forecast area
by Sun afternoon...followed by increasing rain chances late Sun night
into Monday. For tonight with mostly clear skies and lighter winds near
the surface most areas along and north of the 1-10 corridor will
experience a light to moderate freeze late tonight and early Sun
morning. Wind chills will also dip into the middle to upper 20s for most
inland areas...and the lower 30s near the coast by early Sun morning.

As for temperatures with lean towards the cooler met/European model (ecmwf) for lows tonight
and the cooler mav guidance for highs on sun. Lows tonight will
range from the middle to upper 20s for most inland areas generally
north of the I-10 corridor and the lower 30s further south towards
the coast. 32/ee

Short term /Sunday night through Tuesday night/...a broad middle level
shortwave trough will slowly advance toward the Mississippi Valley
region Sunday night into Monday...before moving across the Tennessee
Valley/Gulf Coast states Monday afternoon into Monday night. Surface
high pressure will move eastward toward the eastern Seaboard and
western Atlantic Sunday night and Monday...while the next cold front
approaches the lower Mississippi Valley region Monday morning. Low
level southerly flow will bring a return flow of moisture northward
back into the forecast area Sunday night into Monday...with surface
dewpoints expected to rise into the middle to upper 50s across most of
our region by Monday afternoon.

Models vary on the availability of deep layer moisture Sunday
night...but enough moisture and lift may be available to aid in the
development of isolated to scattered showers mainly over western and
northwestern portions of the forecast area. Deep layer moisture and
lift will increase considerably from west to east across our area
Monday as the shortwave trough moves from the Mississippi Valley
toward the Gulf Coast region. This feature will bring a high chance
of showers to our region Monday along with scattered thunderstorms.
Our environment will continue to trend high shear/Low Cape again
Monday. Deep layer shear values between 40-50 knots seem a good bet
across the region...with 850 mb wind speeds averaging 35-45 knots.
As mentioned...instability continues to remain a limiting severe
weather factor given the amount of cloud cover and expected
temperatures only reaching into the middle 60s to around 70 degrees. The
GFS and European model (ecmwf) show MLCAPE values generally averaging 500 j/kg or
below...and the NAM seems a bit overdone with its higher values. Middle
level lapse rates will tend to steepen Monday afternoon...which
could trend toward a marginal risk of hail with some of the stronger
storms. Given the above factors...the overall severe weather risk
still looks quite marginal/limited across our area Monday at this
point in line with the latest Storm Prediction Center day 3 outlook...but is something we
will continue to monitor over the next 48 hours.

Precipitation chances will decrease from west to east Monday evening
as the front moves across the region...followed by a much drier
airmass through the deep layers late Monday night into Tuesday night.
Low temperatures Monday and Tuesday night will average in the 40s
with highs Tuesday in the middle to upper 60s. /21

Long term /Wednesday through Saturday/...dry northwest to zonal flow
aloft is expected during the middle to latter half of the week as an
upper level ridge of high pressure builds into the Gulf of Mexico.
Lows Wednesday and Thursday morning generally will average in the
lower to middle 40s except a little warmer near the coast...with highs
in the middle 60s to around 70. High temperatures will trend toward the
lower 70s by Friday and Saturday. A shortwave trough may send the next
cold front toward our area Saturday or Saturday night...but will have
little in the way of moisture to work with. Dry weather is
anticipated through the long term portion of the forecast. /21

Marine...a moderate offshore flow is expected to continue over the
marine area through tonight followed by a moderate east to southeast
flow Sunday...shifting mostly southeast Sun night. Winds shift
mostly south and increase on Monday ahead of a cold front approaching
from the west. Seas possibly up to 7 feet can be expected with the
onshore flow ahead of the front. A Small Craft Advisory may be
required. Scattered to numerous showers and thunderstorms are also
expected ahead and along the front Monday and Monday night. The cold front
is expected move across the marine area by late Monday night leading to
a moderate offshore flow through early Tuesday afternoon. Seas will
diminish in the wake of the front by early Tuesday. Winds will shift
southwest late Tuesday and early Tuesday night ahead of another cold front
approaching from the west. A light to moderate offshore flow is
expected in the wake of the second cold front Wednesday through early Thursday.


Mob watches/warnings/advisories...


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