Flash Flood Watch 1, NWS Mobile, AL

Area Forecast Discussion...UPDATED
National Weather Service Mobile AL
1130 AM CST Wed Jan 2 2019

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

&&

.AVIATION...
18Z issuance...A steady stream of low stratus continues to flow
atop a stalled frontal boundary atop the area. A persistence type
approach will be carried forward in the near term forecast as
little change is noted in the current weather pattern. Cig bases
within the LIFR categories. Fog also continues to be problematic,
more so along much of the coastal zones with IFR/LIFR categories.
Winds light from the northeast north and west of front and
southeast to south, southeast of the boundary. /10

&&

.PREV DISCUSSION... /issued 1000 AM CST Wed Jan 2 2019/

DISCUSSION...See updated information for land and marine areas below.

UPDATE...Latest observations show fog, some of it dense,
continues to persist along the coastal zones. Latest hi res model
output for vsby thru the day indicates the need to extend the
current dense fog advisories, mainly for the coastal portions out
to 6 PM this evening. The afternoon package will likely extend
this into the night, but will await new data before a decision
will be made. /10

MARINE...Latest web cameras indicate fog persisting near and off
the coast. Latest hi res model output for vsby thru the day
indicates the need to extend the current marine dense fog
advisories out to 6 PM this evening as well. An extension into
the night will be likely on the afternoon package. /10

PREV DISCUSSION... /issued 522 AM CST Wed Jan 2 2019/

DISCUSSION...Updated for latest aviation discussion below.

AVIATION...
12Z issuance...Mostly LIFR conditions around the area this morning
as low stratus remains firmly in place. Ongoing fog generally
along and southeast of I-65 will continue into the mid-morning
hours before dissipating by this afternoon. Fog could be dense in
spots, especially right along the coast. A Dense Fog Advisory
remains in effect until 10 am CST for coastal counties. LIFR cloud
cover sticks around throughout the period, though could briefly
improve to IFR this afternoon. Scattered showers also continue to
develop throughout the period, with locally lower visbys in and
around any heavier rain. /49

PREV DISCUSSION... /issued 444 AM CST Wed Jan 2 2019/

NEAR TERM /Now Through Wednesday night/...A weak front remains
stalled over the area roughly along an Andalusia, AL to Pensacola,
FL line and beyond into the Gulf of Mexico. This front moves
little through the near term, perhaps lifting inland just a tad
and reintroducing parts of coastal SW AL to a warm and moist
onshore flow. Patchy dense fog along the coast this morning
dissipates by this afternoon. Scattered light to moderate rain
showers continue along the front, supported by weak isentropic
upgliding of a very moist lower-tropospheric flow out of the
south-southwest. Like yesterday, rainfall amounts will be fairly
low due to the scattered nature of these showers and modest rain
rates. Most areas can expect to see maybe a couple tenths of an
inch of rain throughout the period, up to around half an inch in
heavier spots. Meanwhile, a band of moderate to heavy rainfall
sets up to our northwest over central Mississippi as the next
system approaches from the west. While the heaviest rainfall is
expected to remain to our northwest during this period, its
proximity to our interior SW AL and SE MS counties could lead to
slightly higher rain totals compared to the rest of the area, with
accumulations more in the 0.50" - 0.75" range. Will need to
continue monitoring rivers over SE MS and SW AL as the heavy
rainfall upstream over central MS may slow the rate at which river
levels are currently falling and prolong ongoing flooding issues.
An Areal Flood Warning remains in effect for portions of Perry,
Wayne, and Greene Counties in SE MS through at least 11 am CST
today. Temperatures during the near term will continue to be
dictated by the location of the stalled front, with areas to its
north/west seeing upper 50s to low 60s and areas south/east in the
upper 60s to low 70s. /49

SHORT TERM /Thursday Through Friday night/...A large closed upper
low pressure area over the southern plains on Thursday will move
east across the lower Mississippi River region late Thursday
night into Friday morning, and then across the southeast states
through the remainder of the short term. A weak surface front just
east of I-65 Thursday morning will lift northward Thursday
afternoon through the overnight hours as a surface low pressure
area develops ahead of the upper trough across the northwest Gulf
of Mexico and southern Louisiana and deepens to around 1006mb as
it lifts northeastward, reaching the northern portions of
Mississippi and Alabama by late Thursday night.

Mainly scattered to likely light to occasional moderate rain
showers will occur through much of the day Thursday, although we
are expecting definite rain chances to enter into our inland
southeast Mississippi counties by late Thursday afternoon as the
surface low moves over southeast Louisiana. Rain coverage will
then increase from west to east Thursday night as the surface low
passes just to the northwest of the forecast area. A 125 knot
upper level jet is expected southeast of the upper low, and
approach the region from the west Thursday evening, and strengthen
to 140 knots over Alabama by noon Friday. An 850mb jet max of
between 40 to 50 knots is expected over the forecast area
Thursday night as the surface low deepens. There should be enough
deep layer lift to support elevated isolated thunderstorms
embedded within the main cluster of showers in the warm sector west
of the Alabama River Thursday afternoon and then overnight across
the entire forecast area. With very low MLCape values expected,
we are only expecting a few strong thunderstoms at best.

The rain will be the main concern, especially with already
saturated soils across the area. Additional widespread rainfall
amounts are expected to range from 1 to 2 inches, with localized
higher amounts as high a 4 inches north of I-10, leading to
possible more areal and river flooding problems. The rain will
taper off from west to east Friday morning as the upper level
trough shifts eastward, the surface low continues to lift
northeast, and a cold front passes through the forecast area. A
dry weather pattern will then occur through the remainder of
the short term. /22

LONG TERM /Saturday Through Tuesday/...The dry weather pattern
will continue through Monday afternoon as a broad upper level
ridge of high pressure moves over the southern states, and an
area of surface high pressure builds in from the west. A fast
moving upper level shortwave exits the central plains Monday
evening, and passes over the region late Monday night and Tuesday,
while an associated deepen surface low pressure area is expected
to pass well north of the region. As a result, increasing clouds
and isolated to low-end scattered light rain showers are expected
Monday night into Tuesday ahead of a cold front approaching from
the northwest. /22

MARINE...A weak front remains stalled roughly along a line
extending from the mouth of Pensacola Bay southwest towards the
mouth of the Mississippi River. As a result, Mobile Bay, the
Mississippi Sound, and nearshore Alabama waters are currently
seeing a north to northeast flow while the remainder of the marine
area sees an onshore flow. Dense fog will continue over much of
the marine area through this morning and a Dense Fog Advisory
remains in effect until 10 am CST. The front lifts inland later
today, leading to onshore flow across the entire marine area this
evening and tonight.

The front then pushes back south through the marine area early
Thursday morning, leading to a moderate northerly flow during the
day Thursday. Moderate to strong onshore flow redevelops Thursday
night ahead of a much stronger cold front, which pushes through
early Friday and brings a strong offshore flow into the weekend.
/49

&&

.MOB WATCHES/WARNINGS/ADVISORIES...
AL...High Rip Current Risk from Thursday morning through Friday
     morning for ALZ265-266.

     Dense Fog Advisory until 6 PM CST this evening for ALZ265-266.

FL...High Rip Current Risk from Thursday morning through Friday
     morning for FLZ202-204-206.

     Dense Fog Advisory until 6 PM CST this evening for FLZ202-204-
     206.

MS...None.
GM...Dense Fog Advisory until 6 PM CST this evening for GMZ630>636-
     650-655-670-675.

&&

This product is also available on the web at:
http://weather.gov/mob

Hazardous Weather Outlook...UPDATED
National Weather Service Mobile AL
125 PM CST Wed Jan 2 2019

ALZ265-266-FLZ202-204-206-032000-
Mobile Coastal-Baldwin Coastal-Escambia Coastal-Santa Rosa Coastal-
Okaloosa Coastal-
125 PM CST Wed Jan 2 2019

...DENSE FOG ADVISORY IN EFFECT UNTIL 6 PM CST THIS EVENING...
...HIGH RIP CURRENT RISK IN EFFECT FROM THURSDAY MORNING THROUGH
FRIDAY MORNING...

This Hazardous Weather Outlook is for southwest Alabama and
northwest Florida.

.DAY ONE...This Afternoon and Tonight.

Please listen to NOAA Weather Radio or go to weather.gov/mob (see
Fast Access Product Section) for more information about the
following hazards.

   Dense Fog Advisory.

.DAYS TWO THROUGH SEVEN...Thursday through Tuesday.

Please listen to NOAA Weather Radio or go to weather.gov/mob (see
Fast Access Product Section) for more information about the
following hazards.

   High Rip Current Risk.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is not expected at this time.

ALZ051>060-261>264-FLZ201-203-205-MSZ067-075-076-078-079-032000-
Choctaw-Washington-Clarke-Wilcox-Monroe-Conecuh-Butler-Crenshaw-
Escambia-Covington-Mobile Inland-Baldwin Inland-Mobile Central-
Baldwin Central-Escambia Inland-Santa Rosa Inland-Okaloosa Inland-
Wayne-Perry-Greene-Stone-George-
125 PM CST Wed Jan 2 2019

This Hazardous Weather Outlook is for south central Alabama,
southwest Alabama, northwest Florida and southeast Mississippi.

.DAY ONE...This Afternoon and Tonight.

Patchy fog likely to reform overnight. Visibility could be reduced
to less than a quarter mile at times in some areas, especially closer
to inland sounds and rivers.

.DAYS TWO THROUGH SEVEN...Thursday through Tuesday.

Some strong storms are possible on Thursday. Heavy rain is also
possible Thursday into early Friday, which could lead to continued
or worsening areal and river flooding generally along and northwest
of a line from a Camden Alabama to Leakesville Mississippi line.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is not expected at this time.

GMZ630>636-650-655-670-675-032000-
Northern Mobile Bay-Southern Mobile Bay-Mississippi Sound-
Perdido Bay-Pensacola Bay System-Western Choctawhatchee Bay-
Eastern Choctawhatchee Bay-
Coastal waters from Pensacola FL to Pascagoula MS out 20 NM-
Coastal waters from Okaloosa Walton County Line FL to Pensacola FL
out 20 NM-Waters from Pensacola FL to Pascagoula MS from 20 to 60 NM-
Waters from Okaloosa Walton County Line FL to Pensacola FL from
20 to 60 NM-
125 PM CST Wed Jan 2 2019

...DENSE FOG ADVISORY IN EFFECT UNTIL 6 PM CST THIS EVENING...

This Hazardous Weather Outlook is for the coastal waters of Alabama
and northwest Florida.

.DAY ONE...This Afternoon and Tonight.

Please listen to NOAA Weather Radio or go to weather.gov/mob (see
Fast Access Product Section) for more information about the
following hazards.

   Dense Fog Advisory.

.DAYS TWO THROUGH SEVEN...Thursday through Tuesday.

Fog development will remain likely into early Thursday morning.
Visibilities may be reduced to less than one mile at times.

A moderate to strong onshore flow Thursday night becomes west
northwest into the day Friday following the passage of a strong cold
front. Seas to trend higher to close out the week.