Area Forecast Discussion
Issued by NWS Mobile, AL

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
631
FXUS64 KMOB 290306
AFDMOB

Area Forecast Discussion
National Weather Service Mobile AL
1006 PM CDT SUN AUG 28 2016

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

&&

.UPDATE...Minor adjustments to the overnight forecast package.
Adjusted PoPs downward as convection has generally shutdown this
evening. Only kept slight chance closer to the coast and slight to
low end chance over the Gulf where some instability will remain
available. Cloud cover decreasing overnight will open the door for
patchy late night and early morning light fog development. New
package out shortly. /08

&&

.PREV DISCUSSION... /issued 657 PM CDT SUN AUG 28 2016/

DISCUSSION...Updated for latest aviation discussion below.

AVIATION...
00Z issuance...Only spotty convection lingering this evening and
should come to an end over the next hour or two. Some areas of light
fog (MVFR) will likely set up overnight and dissipate in the morning
otherwise VFR will prevail for the next 24-hours. /08

PREV DISCUSSION... /issued 452 PM CDT SUN AUG 28 2016/

NEAR TERM /Now Through Monday/...Latest radar loops continue to show
scattered showers and thunderstorms forming just inland from the
coast or near and along the I-10 corridor moving west at 20 to 30
mph. Gusty winds up to 30 mph...frequent cloud to ground lightning
and periods of very heavy rainfall will accompany the stronger storms
through early this evening. Further development will be mostly over
the lower half of the forecast area generally along and south of a
line stretching from Andalusia Al to Hattiesburg Ms. With the lack of
good forcing aloft showers and thunderstorms will begin to taper off
slowly by early this evening as afternoon heating decreases.

Through Mon afternoon upper ridge that stretches from the mid
Atlantic region to the central gulf states and further west to the
central plains states will continue to slowly weaken as a newly
formed tropical depression off the Carolina coast shifts west...
combined with newly formed Tropical Depression Nine shifting west
from the Florida Straits to the se gulf through Mon afternoon. Near
the sfc latest progs from most of the model guidance show this system
over the lower gulf by mon slowly becoming better organized as it
shifts west tonight and on Mon...then shifting north and northeast by
midweek. Latest model soundings across the central gulf coast region
show better moisture in the boundary layer through the next 24 hours
with pwats climbing to near 1.7 inches generally over the northern
half of the forecast area and around 2.0 inches to the south. Sfc
based instability continues to be marginal through this time frame
with sfc based capes climbing to near 1500 j/kg mostly over the lower
half of the forecast area combined with lapse rates ranging from 6.0
to 6.5 suggesting a few strong thunderstorms will be possible mon
afternoon also...moving mostly east to west around 20 mph. Gusty
straight line winds mostly from 30 to 40 mph...frequent lightning and
heavy rain will accompany the stronger storms. The best lift in the
mid levels was also confined to lower half of the forecast area
generally east of Pensacola Fl.

Lows tonight will range from the mid 70s inland and the mid to upper
70s closer to the coast. Highs Mon will be mostly in the lower 90s
inland and the upper 80s to near 90 along the coast. 32/ee

SHORT TERM /Monday night Through Wednesday night/...Tropical
Depression Nine is forecast to strengthen into a tropical storm by
Monday evening over the southeastern Gulf of Mexico, and continue a
slow moving track to the west-northwest. The tropical storm is then
forecast to turn to a northerly direction Tuesday afternoon, and then
possibly to a northeasterly direction Wednesday afternoon. By
Wednesday night the system is forecast to enter into the northeastern
Gulf of Mexico, but this track will likley be adjusted with issuance
of each advisory. Immediate impacts from the system across the
forecast area will be an increase in rip currents along the area
beaches as longer period swells generated from the system reach the
northern gulf coast as early as Monday night.

Meanwhile a weak surface ridge of high pressure along the southern
appalachians will remain in place through Tuesday and then weaken on
Wednesday as the tropical system turns to the northeast. The upper
level ridge of high pressure extending from the Ohio River Vally
eastward over the Virginias to the western Atlantic Ocean will weaken
but remain largely intact through Monday night and then split in two
Tuesday and Tuesday night as an upper shortwave dives southeast over
southeast Canada and the northeast conus regions. Precipitable water
values will remain between 1.50 and 1.75 inches across the forecast
areas. Expect mainly isolated coverage of showers and thunderstorms
each day, with scattered coverage across our coastal zones. Convection
should diminish with loss of daytime heating each night, but enough
moisture and over-running may remain in place to keep a slight
chance to chance of showers and storms near the coast both Monday and
Tuesday nights, with dry conditions expected inland areas. Isolated
to scattered coverage of showers and thunderstorms is then expected
across the southern half of the forecast area Wednesday night as the
tropical system potentially enters the northeast Gulf. For the
latest information regarding Tropical Depression Nine, please check
the National Hurricane Center website at http://www.nhc.noaa.gov and
our website at http://weather.gov/mob.

Seasonably hot/humid conditions will otherwise persist, with highs
in the lower to mid 90s inland and around 90 near the coast both
Tuesday and Wednesday. Lows will be in the lower to mid 70s inland
areas, except upper 70s to around 80 degrees near the immediate coast
and beaches. /22

LONG TERM /Thursday Through Sunday/...Much uncertainty continues in
the extended forecast range as to the track and intensity forecasts
of the tropical system. Both the 12Z GFS and ECMWF move the system
northeastward over the Florida Big Bend region, but other model
guidance continues to offer a variety of solutions. We will
continue to closely monitor this system over the next several days
before specific impacts in the extended can be resolved.

We have otherwise continued to follow a blended approach to the
extended forecast, generally keeping POPs fairly low in the isolated
to low-end scattered coverage range on Wednesday and Thursday, then
trend the coverage upward just a bit toward the end of the week.
Little variation in day-to-day temperatures is indicated through the
extended period, with highs each day in the lower to mid 90s inland
and closer to 90 near the coast, with lows each morning in the 70s.
/22

MARINE...Main concern for this upcoming week will be the development
of newly formed tropical depression nine moving from the Florida
Straits to the se gulf through mon then turning north and moving
northward through the remainder of the week. With this pattern
easterly winds and seas will gradually increase throughout the week.
Showers and thunderstorms will also become better developed through
the week...with gusty straight line winds and heavy rain in squalls
becoming likely later in the week. Tides above normal will also be
likely. For more information on Tropical Depression nine monitor the
National Hurricane Center website at http://www.nhc.noaa.gov and our
website at http://weather.gov/mob for the very latest information.
32/ee

&&

.MOB Watches/Warnings/Advisories...
AL...None.
FL...None.
MS...None.
GM...None.
&&

$$

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



USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.