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Area forecast discussion 
National Weather Service Mobile Alabama
954 PM CST Wednesday Mar 4 2015

Update...just did a quick update to grids and zone forecast product.
A persistent mesoscale lolvl convergence area has set up over the
forecast area this evening with a thin line of showers training from
southwest to northeast along the boundary. Adjusted rain chances
upward along this axis for the remainder of the evening...then still
expecting coverage to become more widespread from the west late
tonight as the front begins moving through the local forecast area. The
current showers are moving inland off the Gulf into southern Mobile
County and continue northeastward across northern Baldwin County and
further inland all the way to the Evergreen area (aligned just to
the west of I-65). The remainder of the forecast was in pretty good
shape. Dense fog advisory continues for coastal zones...where dense
fog is beginning to develop over the coastal areas of Florida
Panhandle and will likely develop over coastal Alabama as well.
Offshore marine fog continues as well. All necessary products have
been updated and transmitted. 12/ds

&&

Previous discussion... /issued 403 PM CST Wednesday Mar 4 2015/

Short term [tonight through friday]...as of 3pm the cold front is
moving into far northwest Alabama/north ctrl MS/southern Arkansas. The boundary
will continue to steadily progress south and east through the night
with the front moving into the far northwest zones likely just after
midnight. The front will approach the I-65 corridor shortly before
or near daybreak...and will push south and east of the forecast area
by midday Thursday. Temperatures will drop very quickly behind the
front (on order of 20-30 degrees in just an hour or two). The exact
location of the front will impact low temperatures. However...lows will
generally be in the low to middle 60s east of I-65...with upper
30s/lower 40s over far inland southeast MS/SW Alabama. With the front passing
through in the morning hours...highs will be reached very early in
the day with temperatures dropping through the daylight hours.

A chance for showers will continue ahead of the front tonight under
a continued warm air advection regime. The chance for thunder looks
low due to a persistent middle level cap around 700 mb. Meanwhile...a
band of showers is likely to accompany the actually front with
patches of light rain developing in the wake of the boundary. The
slope of the front is very shallow...with the 850 mb front located
well to the northwest of the surface boundary. Therefore...the band of more
moderate rain is likely to impact the far northwest portions of the
forecast area late morning through afternoon in association with the
850 mb front. Temperatures will be dropping into low to middle 30s by
late morning/early afternoon roughly from Waynesboro and Butler
northward. The consensus of the guidance brings the wet bulb
freezing line into far northern Choctaw County during this
time...and this will be the location that will have the best chance
of seeing a period of light freezing rain. Further to the south...a
cold rain is currently expected. We will have to continue to monitor
temperatures closely as the front moves through. At this point...we do not
plan to issue a Freezing Rain Advisory for Choctaw County as
confidence is not high that there will be any ice accrual. While
temperatures near freezing are possible...the combination of very warm
ground temperatures (it reached 80 today) with the greater insolation
factor of the March sun angle will make it very hard to accrue ice
during the middle of the day. Will continue to monitor closely.

As mentioned in the previous discussion...expect areas of dense fog
to redevelop tonight across areas along and south of I-10 and a
dense fog advisory is in effect for those zones. Patchy dense fog is
also possible further inland ahead of the front but confidence is
not as high. The fog will clear with the frontal passage.

One last note...it will become breezy to windy in the wake of the
front on Thursday which will make wind chills drop into the 20s/30s
over much of the forecast area. Winds chills mainly in the 40s along
the immediate coast. 34/jfb

The cold front will continue to move well south into the southern
Gulf and southern portions of the Florida Peninsula Thursday night as cold
surface high pressure on the order of 1039 mb builds from northeast
Texas into the lower Mississippi...Tennessee and Ohio valleys. Deep
layer moisture and lift will continue to push southward and will
generally extend from far southeast MS and southwest Alabama through the
northwest Florida Panhandle during the evening before mostly pushing
offshore and to the east of our forecast area late Thursday night.
Temperature profiles remain warm enough to keep a mention/slight
chance of rain in the forecast generally to the southeast of a
Wiggins MS...Monroeville Alabama....Luverne Alabama line Thursday evening
before any lingering light rain becomes focused offshore to near the
immediate northwest Florida Panhandle coast Thursday night. Much colder
temperatures are otherwise expected Thursday night with lows ranging
from the middle to around 30 over interior southeast MS and southwest Alabama
to the middle to upper 30s near the immediate coast.

A much drier airmass will settle southward over the central Gulf
Coast region Friday underneath zonal flow aloft...and we will
continue a dry forecast across the region. A gradual decrease in
cloud cover is also expected. A broad cool surface ridge of high
pressure will extend from the vicinity of south and East Texas to the
lower Mississippi and Tennessee Valley region Friday. Highs Friday
afternoon should continue to average well below normal...with
readings in the upper 40s to lower 50s inland to the middle to upper 50s
near the immediate coast. /21

Long term [saturday through wednesday]...dry zonal flow continues
across the region Saturday and expect slightly warmer temperatures.
The next shortwave trough will cross into the Southern Plains
Sunday...and deep layer moisture will increase and spread across
south Texas...the northwestern Gulf and northeastward toward the central
Gulf Coast region ahead of this next feature Sunday afternoon into
Monday. Will continue to bring rain chances upward into the 30-40
percent chance range across most locations during this time frame. A
wet weather pattern may continue into the middle portion of next week
as southwest flow aloft persists...though medium range guidance does
have some disagreement on timing of the next wave of deep moisture
Tuesday into Wednesday. We left a chance of rain showers in the
forecast Tuesday and Wednesday for now. Temperatures will trend
upward toward normal values early to middle next week. /21

Aviation...
18z issuance...
daytime heating has resulted in strong mixing and a lifting of ceilings
to MVFR or VFR levels across much of the region. IFR/LIFR ceilings/visibilities
will be predominate along coastal Alabama/northwest Florida tonight under a continued
warm and moist southerly flow. A cold front will push through the
area overnight into Thursday morning...with frontal passage at the
taf sites expected to be around the 15-16z time frame. However...IFR
to LIFR ceilings will likely persist in the wake of the front along with
periods of light rain. 34/jfb

Marine...areas of dense fog will continue to impact the near shore
coastal waters through early Thursday morning. While conditions have
improved some this afternoon...dense fog is expected to quickly
redevelop after sunset. Otherwise...a light to moderate southerly
flow will persist tonight ahead of an approaching cold front. The
front moves through the coastal waters by late Thursday morning with
a strong offshore flow developing in its wake. A Small Craft
Advisory will be in effect from 10am Thursday until 10am Friday.
Winds and seas will diminish Friday night as high pressure builds in
from the north. There is the potential for strong winds to impact
the marine area early next week as a surface low develops over the
northern Gulf and tracks northeast. The timing and strength of the
low is still uncertain. 34/jfb

&&

Preliminary point temps/pops...
Mobile 58 60 30 52 34 / 50 60 20 10 05
Pensacola 64 65 37 54 38 / 40 60 20 10 05
Destin 63 65 39 54 44 / 40 50 30 20 10
Evergreen 58 60 32 52 32 / 50 60 20 10 05
Waynesboro 42 44 25 48 27 / 60 70 10 05 05
Camden 47 49 27 50 32 / 60 70 10 05 05
Crestview 64 66 36 56 36 / 50 60 20 10 05

&&

Mob watches/warnings/advisories...
Alabama...dense fog advisory until 10 am CST Thursday for alz063-064.

Florida...dense fog advisory until 10 am CST Thursday for flz002-004-006.

MS...none.
GM...dense fog advisory until 10 am CST Thursday for gmz630>635-650-
655.

Small Craft Advisory from 10 am Thursday to 10 am CST Friday for
gmz630>635-650-655-670-675.

&&

$$

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