Area Forecast Discussion
Issued by NWS Mobile, AL

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FXUS64 KMOB 221745
AFDMOB

Area Forecast Discussion
National Weather Service Mobile AL
1145 AM CST Wed Nov 22 2017

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

&&

.AVIATION...
22/18Z issuance...VFR conditions across the region through the
next 24 hours with mainly high clouds expected. Could see some
low to mid level clouds over portions of south central AL and the
northwest FL panhandle today and tonight, but coverage not enough
to warrant anything below VFR ceilings at any time during
forecast period. Gusty northerly winds around 10 to 15 knots with
gusts to near 20-25 knots this afternoon. North winds continue
overnight, but decrease to around 10 knots and with fewer strong
gusts. 12/DS

&&

.PREV DISCUSSION... /issued 551 AM CST Wed Nov 22 2017/

DISCUSSION...Updated for latest aviation discussion below.

AVIATION...
12Z issuance...VFR conditions are expected across the region
through the next 24 hours. Broken high level cloud cover will
spread overhead across the region through the day, while some
scattered to broken VFR low to mid level decks will impact
portions of south central AL and the northwest FL panhandle.
Northerly winds will increase to around 10 knots with a few higher
gusts inland, and 10-15 knots with a few gusts around 20 knots
near the coast this morning. /21

PREV DISCUSSION... /issued 420 AM CST Wed Nov 22 2017/

NEAR TERM /Now Through Wednesday night/...Early morning water
vapor imagery and 500 mb height analysis show an upper level trough
axis translating across the Ohio and Tennessee Valley regions, with
another deeper upper level trough in the vicinity of the
northwestern Gulf of Mexico. An associated surface cold front was
meanwhile pushing into southeast Louisiana, southeast Mississippi
and central portions of Alabama. Cool and dry weather conditions are
in place over our forecast area in advance of these features early
this morning.

The upper level trough axis will gradually pivot eastward across the
central Gulf Coast region and the adjacent central Gulf of Mexico
today, while the surface cold front quickly pushes offshore this
morning. Deep layer moisture and ascent in advance of the upper
level trough axis will spread northeastward across the northeastern
Gulf of Mexico and toward northern portions of Florida this
afternoon into tonight. Short range models indicate that the
northwestern fringe of this moisture and lift may skirt far
southeastern portions of our area (i.e. the NW Fl Panhandle) this
evening and tonight, so will carry a low chance of rain roughly
southeast of a Crestview-Navarre line. The best chance of rain
showers should be focused over our offshore eastern marine zones
and into the Florida Big Bend region east of our area. Northerly
winds are otherwise set to increase today as the MSLP gradient
increases courtesy of building high pressure. We trended wind
speeds a little higher than blended guidance. Conditions may be a
bit breezy near the immediate coast today and tonight. Cooler
temperatures are anticipated today, with highs ranging from around
60 to the mid 60s over the northwestern half of the area, with
readings in the mid 60s to around 70 southeast. Another chilly
night is expected, with lows ranging from the mid 30s to around 40
generally along and northwest of I-65 (potentially reaching near
freezing over far interior southeast Mississippi and southwest
Alabama) and in the mid 40s to around 50 farther east and closer
to the coast/beaches. /21

SHORT TERM /Thursday Through Friday night/...Period begins with the
base of the main upper level trough moving through our region. The
aforementioned SE Glfmex surface low moves east on Thanksgiving day.
Wrap-around cloudiness will still exist east of I-65 and southeast
to the NW FL Panhandle on Thursday, Thursday night and into early
Friday before gradually dissipating while advecting off to the
southeast. The rest of Friday should be a very nice day. Temperatures
remain cool during the period only reaching the 60s deg(F) for highs
on Thursday and Friday afternoons. Overnight lows on Friday will range
from the mid 30s deg(F) over interior SE MS to the upper 40s deg(F)
near Destin, FL. /23 JMM

LONG TERM /Saturday Through Tuesday/...In short, for most of period,
region remains on the SW edge of the large scale main longwave trough
that will be located first along and then moving off the East Coast
by Monday. This means a deep NW flow persists with large-scale subsidence
to bring cool sunny days and very cool nights. By Monday, normalized
upper height anomalies finally rise back above normal (after being
below normal for days due to the main longwave trough expected to form
in the short-term) once again as progressive longwave ridge moves from
the Plains to the Ohio and Tennessee Valleys by late Tuesday. So Monday
and Tuesday will be warmer compared to the cooler weekend temperatures.
The lower atmosphere also moistens on Tuesday given a solid return
flow in the wake of the previous anticyclone. Highs in the 60s to around
70 deg(F) on Saturday but in the 60s on Sunday and Monday. Warmer once
again Tuesday. Overnight lows generally in the 40s deg(F) except 30s
on Monday morning. /23 JMM

MARINE...A moderate to strong northerly flow will prevail over the
marine area today and tonight in the wake of a cold front that moves
through this morning. Wind speeds will be at cautionary levels over
most bays and sounds, with speeds increasing to advisory thresholds
early this morning over the offshore coastal waters. Winds over
the offshore waters may abate slightly this afternoon, but should
quickly increase back to advisory thresholds this evening into
late tonight, so will maintain the Small Craft Advisory through
late tonight. Seas build to 3-5 feet near shore and 4-6 feet well
offshore through tonight. Moderate northerly to northeasterly flow
continues Thursday into Friday as high pressure builds from the
Plains toward the Gulf Coast region and as low pressure lifts across
the eastern Gulf toward Florida. Offshore flow is reinforced late this
weekend as the next cold front pushes through the marine area. /21

&&

.MOB WATCHES/WARNINGS/ADVISORIES...
AL...None.
FL...None.
MS...None.
GM...Small Craft Advisory until 3 AM CST Thursday for GMZ650-655-670-
     675.

&&

$$

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