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Area forecast discussion...updated 
National Weather Service Mobile Alabama
720 am CST Monday Mar 2 2015

Update...did a quick update to current zone forecast to lower probability of precipitation
a tad for the remainder of this morning. Latest radar loops continue
to show the heavier precipitation just to the west earlier this morning
eroding slowly over the forecast area as it continues to move east.
Dense fog now occurring in most places in the County warning forecast area will be slow to
lift this later morning. As a result the dense fog advisory may need
to extended later this morning. Stay tune for further updates. 32/ee

&&

Marine...did a quick update to the current marine forecast mainly to
adjust rain chances for precipitation for the remainder of this morning.
Dense fog will be slow to lift today possibly lingering into the late
morning or early afternoon hours. As a result the dense fog advisory
may be extended into the late morning or early afternoon hours later
this morning. Stay tuned for further updates. 32/ee

&&

Previous discussion... /issued 434 am CST Monday Mar 2 2015/

Short term (today through Wednesday night)...main concern for most
areas in the County warning forecast area through tonight will be the persistent fog
development early this morning continuing through about 9
am...reforming again this evening and overnight continuing through
early Tuesday morning. Latest model guidance still depicts better
moisture near the surface the advect inland today and tonight
generally from a light onshore flow...thus setting the stage for
continued advection fog to move northward across the region through
the next 24 hours. Dense fog will likely redevelop near the coast
late this afternoon or early this evening then spread inland during
the evening and overnight hours. Better coverage of showers across
much of the forecast area will also continue through about middle
morning today then gradually shift northward through this afternoon
and this evening as a very weak frontal boundary over the region
shifts northward along with better forcing in the middle levels
dampening and shifting east. As for temperatures due to rain and clouds
through this evening will undercut most of the current MOS guidance
1 to 3 degrees for most areas through this afternoon then lean
towards the warmer mav guidance for lows tonight. Highs today will
climb to the lower to middle 60s for extreme northern parts of the
forecast area...upper 60s to lower 70s for for most inland areas and
the middle 60s closer to the coast. Lows tonight will be in the middle to
upper 50s for most areas. 32/ee

For Tuesday through Wednesday night...a positively tilted longwave
trough over the western states advances eastward into the eastern
plains and interior eastern states through Wednesday night. An
associated surface low will be located over the Central Plains
Tuesday morning and moves well off to the northeast through
Wednesday. The surface low brings a trailing cold front into the
interior Gulf coastal states Wednesday morning which then continues
slowly southward through the forecast area Wednesday afternoon into
Wednesday night...ushering much colder air into the area. Will have
slight chance probability of precipitation for most of the area Tuesday into Tuesday night
due to modest isentropic lift. With the continuing southerly flow
over cool near shore waters...have added areas of fog developing
over a portion of the coastal counties during the late night hours.

Good chance probability of precipitation follow for most of the area on Wednesday with the
front beginning to move into the northernmost portion late in the
afternoon. With daytime highs in the middle 70s and surface dewpoints
in the middle 60s...0-3 km MUCAPES look to attain around 750 j/kg. 0-1
km helicity values look to be 70-100 m2/s2 coincident with the best
instability. Am not expecting severe storm development with this
environment although a few strong storms could develop. Will
continue wording in the hazardous weather outlook stating a low risk
of severe weather.

Things get interesting Wednesday night as much colder air flows into
the region with high rain chances for much of the area. For the
period from 09z-12z Thursday...the GFS has a 4kft deep subfreezing
layer over the extreme northwest portion of the area...roughly from
Waynesboro to Camden...and the NAM is similar with a 3 kft deep
subfreezing layer. The European model (ecmwf) is a bit warmer with a negligible
subfreezing layer. Tried to balance the potential risk of a wintry
mix using this guidance which results in a mix of
rain/sleet/freezing rain mainly over northern Choctaw late Wednesday
night which also blends well with neighbors. Quantitative precipitation forecast amounts during the
wintry mix period will be near 0.10 inches which certainly bodes for
potential travel problems. Considering that exposed objects and
roads will be slower to cool...have gone with a small amount of ice
accumulation of 0.01 inches. Will leave to later shifts to adjust
as more data is available and will add wording to the hazardous
weather outlook highlighting the potential hazards. Should the
event pan out closer to the GFS/NAM solution...this wintry mix area
would need to be expanded over the northernmost portion of the area
with increased accumulation/accrual. /29

Long term (thursday through sunday)...continuing with a blend of
the GFS/NAM/ECMWF...will have a wintry mix of rain/sleet/freezing
rain mainly over northern Choctaw but also extreme northern Wayne
County from 12-15z Thursday then conditions support a return to
light rain before precipitation tapers off and ends later in the
morning. Using the same considerations as in the short term
period...have gone with a small amount of ice accumulation of 0.01
inches and will let later shifts adjust. Dry conditions are
expected Thursday night and Friday then slight chance probability of precipitation return
Friday night into Saturday and increase to chance probability of precipitation by Sunday as
a series of shortwaves move across the region. Highs on Thursday
will range from near 40 well inland to the lower 50s at the coast
and lows Thursday night will range from the upper 20s inland to
Lower/Middle 30s closer to the coast. Temperatures gradually warm
through the remainder of the period with lows Saturday night in the
lower to middle 40s and highs on Sunday in the lower 60s. /29

Aviation...
12z issuance...mostly LIFR to IFR ceilings and visibilities through
03.12z. Widespread fog reducing visibilities to 1/4 of a mile or
less at times will be likely through about 9 am CST this morning
lifting slowly throughout the day. Dense fog will reform again late
tonight and early Tuesday morning possibly leading to another dense fog
advisory overnight and early Tuesday morning. Scattered to numerous
showers also moving east across the region this morning will
gradually decrease in coverage and shift northward this afternoon
and tonight. 32/ee

Marine...areas of dense fog will impact local bays and sounds and
the near shore coastal waters through midweek. A light southeast
wind flow will continue over the marine area through early Tuesday
then shift south and build through Wednesday evening ahead of a
strong cold front approaching from the northwest. The cold front is
expected to move across the northern Gulf by late Wednesday night
into early Thursday morning...leading a strong offshore flow over
the marine area Thursday through early Friday. Seas up to 9 feet
well offshore will be possible in the wake of the front. Northerly
winds and seas will gradually diminish through Saturday as a broad
surface ridge builds to the north. A Small Craft Advisory will be
likely in the wake of the strong cold front later in the week.
32/ee

&&

Preliminary point temps/pops...
Mobile 66 57 73 61 76 / 50 20 20 20 50
Pensacola 66 59 72 61 75 / 50 20 20 20 40
Destin 65 59 70 61 72 / 50 20 10 20 30
Evergreen 70 58 76 60 76 / 50 20 20 20 40
Waynesboro 65 57 75 61 76 / 60 30 20 30 50
Camden 63 58 76 61 75 / 60 30 20 20 40
Crestview 71 57 76 60 77 / 50 20 10 20 30

&&

Mob watches/warnings/advisories...
Alabama...dense fog advisory until 9 am Monday for the following zones:
Butler...Choctaw...Clarke...Conecuh...Covington...
Crenshaw...Escambia...lower Baldwin...lower Mobile...
Monroe...upper Baldwin...upper Mobile...Washington...
Wilcox...

Florida...dense fog advisory until 9 am Monday for the following zones:
coastal Escambia...coastal Okaloosa...coastal Santa Rosa...
inland Escambia...inland Okaloosa...inland Santa Rosa...

MS...dense fog advisory until 9 am Monday for the following zones:
George...Greene...Perry...stone...Wayne...

GM...dense fog advisory until 9 am Monday for the following zones:
Choctawhatchee Bay...coastal waters from Destin to
Pensacola Florida out 20 nm...coastal waters from Pensacola Florida
to Pascagoula MS out 20 nm...Mississippi Sound...northern
Mobile Bay...Pensacola Bay system...Perdido Bay...southern
Mobile Bay...

&&

$$

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