FXUS64 KMOB 231035

Area Forecast Discussion
National Weather Service Mobile AL
435 AM CST Thu Nov 23 2017

.NEAR TERM /Now Through Thursday night/...An upper level trough is slowly
pushing eastward across Alabama early this morning. Skies are clearing
across much of our area along and to the west of the trough axis,though
a deck of stratocumulus and upper level clouds are still holding in
place across eastern portions of our CWA per the latest IR satellite
images and surface observations. Quite a contrast in temperatures across
the region this morning, as locations underneath clear skies are reporting
temperatures in the 30s to around 40 degrees, while areas with cloud
cover are in the upper 40s to mid 50s as of 4 A.M. CST.

The upper level trough will continue to translate east-southeast across
the southeastern U.S. through tonight, leaving our forecast area underneath
dry northwest flow aloft. Stratocumulus decks over eastern portions
of the area should scatter out this morning, while clear skies prevail
across the rest of the region. Surface high pressure building across
the Lower Mississippi and Tennessee Valley regions will result in a
continued cool and dry northerly surface flow over our area today. Highs
today should range from around 60 to the mid 60s over much of the region,
except for a few readings in the upper 60s over portions of the FL
panhandle. Another night of below normal temperatures are expected
tonight with lows ranging in the lower to mid 30s northwest of I-65,
and in the upper 30s to mid 40s farther south and east (except around
50 near the beaches). /21

.SHORT TERM /Friday Through Saturday night/...Period begins with
the current progressive longwave trough and its associated
surface low moving yet further east of the region. Friday will be
dry and cool (i.e., 60s deg(F)) as a deep-layer thermal trough
moves through the area, however, southwest flow quickly resumes by
late day Friday as the next surface front approaches. The front
will be dry and fast- moving, as the mid- and upper-level wave
energy forcing its evolution moves well to our NE by late day
Saturday. Expect the passage of a predominant mid-level cloud band
on Saturday with highs tempered slightly NW of I-65, but in the
60s deg(F), similar to Friday. Winds quickly become NW with the
passage of the front Sat-Eve through Sat night Lows in the 40s
deg(F) Sunday Morning. The overall result is merely that the
frontal passage serves to re-enforce the general deep-layer
longwave troughing that is operating today. /23 JMM

.LONG TERM /Sunday Through Wednesday/...Dry and cool as a deep NW
flow persists through early Monday. By midday Monday, the axis of
the low-level anticyclone associated with Saturday's surface
front will lie from the mid-Atlantic Seaboard to SE LA and this
marks the beginning of yet another return flow event, but this
time with more moisture and potentially some instability leading
into Tuesday. At this time, there are MAJOR differences in the
positioning and even the existence of major features that would
force the next frontal system as it approaches our region. Day 6-7
forecast uncertainty is high, in this case. So, with such
preceding dry air in place on Monday and into Tuesday, which is a
good bet, will be judicious with return flow and increasing rain
chances. It is likely that some decent positive pressure
advection will exist on the low-level isentropic surfaces as
winds turn and flow up Monday's pre- existing cold dome from Tuesday
and into Wednesday. Hopefully more clarity on this situation with
afternoon package. /23 JMM


.MARINE...A tight MSLP gradient between a surface low tracking
across the eastern Gulf of Mexico and a ridge of high pressure
stretching from Texas to the Tennessee Valley is resulting in
continued moderate to strong offshore flow over the marine area
early this morning. Marine observations indicate winds are still
ranging from 18-23 knots over Lower Mobile Bay, the Mississippi
Sound, and the adjacent Gulf Waters so have opted to extend the
Small Craft Advisory for these areas until 9 A.M. CST. Northerly
flow decreases a bit later today, with moderate offshore flow
expected again tonight. Lighter winds are anticipated Friday into
Saturday as high pressure builds across the central Gulf Coast
region. A reinforcing cold front should bring a return to moderate
offshore flow late Saturday into late Sunday. /21


Mobile 62 37 65 43 / 0 0 0 0
Pensacola 66 45 67 50 / 0 0 0 0
Destin 69 50 67 53 / 10 10 0 0
Evergreen 64 37 66 42 / 0 0 0 0
Waynesboro 62 33 64 39 / 0 0 0 0
Camden 61 34 63 42 / 0 0 0 0
Crestview 68 39 68 44 / 0 0 0 0


GM...Small Craft Advisory until 9 AM CST this morning for GMZ631-632-



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