Area Forecast Discussion
Issued by NWS Mobile, AL

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FXUS64 KMOB 242338
AFDMOB

Area Forecast Discussion
National Weather Service Mobile AL
638 PM CDT Fri Mar 24 2017

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

&&

.AVIATION...
00Z issuance...VFR to MVFR ceilings expected tonight with
southeasterly winds relaxing to around 10 knots. Gusty southerly
winds redevelop by 25.16z as showers and thunderstorms approach
from the west. Exact timing of the heaviest thunderstorm activity
remains uncertain, but current guidance has the most concentrated
activity moving west to east across the local area from 25.18z
into the first few hours of the following forecast period. /49

&&

.PREV DISCUSSION... /issued 337 PM CDT Fri Mar 24 2017/

NEAR TERM /Now Through Saturday/...An upper low over the OK/TX
panhandle moves east, to over the mid Mississippi River Valley
tonight through Saturday. The associated surface low moves east over
the Plains until it reaches the Mississippi River Saturday morning,
then meanders north. Even with a bit of weakening in the organization
of the system as it wobbles eastward, the forecast is kept under
moderate to strong onshore flow through the first 24hrs of the
forecast. Winds today have been bumping advisory criteria, but
have been showing a slow downward trend through the day.

Overnight, with the onshore flow continuing and overcast skies, am
expecting overnight temps to remain well above seasonal levels. With
winds remaining on the moderate side, am expecting mostly stratus
with little fog development. As the system moves towards the area
overnight, showers and a few thunderstorms will being to move
over far western portions of the forecast area and mainly towards
sunrise. Lows overnight are expected to range from the upper 50s
northeast to mid 60s along the coast and southwest.

Saturday, the possibility of severe weather continues as the upper
system works its way to the Mississippi River. A lobe of energy
swings around the base of the main system as it begins a northeast
jog Saturday afternoon. With MUCAPE values topping out around
1500j/kg, plus or minus, coming together with 0-3km Helicity values
of 100-200m^2/s^2. Add in mid and upper level enhancement from jet
maxes along the shortwave lobe swinging around the main upper lobe
and moving over the Lower Mississippi River Valley and SPC has put
essentially the entire FA under a slight risk, with better chances
for severe west of a Greenville AL to Pensacola FL line. With
good rotational wind shear, some organized rotating cells mixing
in with the band of storms as the move across the forecast area
Saturday will bring mainly damaging winds, though a tornado can
not be ruled out, although this threat appears to be very limited
at this time. Mid level lapse rates up to around 6.8 C/KM Saturday
afternoon, so the risk of large hail will also continue with the
stronger updrafts. Timing with the current guidance has the band
moving into the western portions of the forecast area late
morning into early afternoon, continuing east across the remainder
of the forecast area during the late afternoon and then weakening
and moving east of the area by mid/late evening. Not to forget,
high temps Saturday generally in the mid 70s.

16/SAM

SHORT TERM /Saturday night Through Monday night/...Upper trof
axis shifts east of our area by midnight saturday (06z Sunday),
with surface trof still lagging back to the west. With this the
potential for strong/severe storms diminishes and ends during the
evening hours Saturday, although some lingering showers and storms
will remain possible into late Saturday night. Forecast area
between systems on Sunday, then another weather system moves
rapidly east across the interior eastern portion of the country
late Monday through Monday night, brining another chance for
showers and storms. For now, any severe threat with that over our
area looks very limited. Overnight lows in the lower 60s through
the period, daytime highs in the upper 70s and lower 80s. 12/DS

LONG TERM /Tuesday Through Friday/...Very progressive pattern
continues through long term period. Previously mentioned system
departs to the east by midday Tuesday with a brief period of
ridging over the forecast area Wednesday before yet another system
approaches from the west by early Thursday. Some indications that
this late week system may have the potential to be a little more
dynamic than previous few, and will have to monitor. Primary
affects over our area at this point look to be late Thursday into
early Friday. Daytime highs remaining above normal, mainly in the
upper 70s and lower 80s through the period. Likewise for overnight
lows ranging from the upper 50s to lower 60s. 12/DS

MARINE...An approaching system from the west combined with a
surface ridge stretching southwest along the East coast will
continue to create moderate to strong onshore flow into Sunday
before becoming lighter. A Small Craft Advisory remains in effect
for most of the marine area, and has now been extended through
7PM Saturday evening. Flow will remain onshore through the
forecast, with another system passing Monday night. This system
will bring a slight increase in the winds once again late Monday
into Monday night. 16/SAM

&&

.MOB WATCHES/WARNINGS/ADVISORIES...
AL...High Rip Current Risk through late Saturday night for ALZ265-266.

FL...High Rip Current Risk through late Saturday night for FLZ202-204-
     206.

MS...None.
GM...Small Craft Advisory until 7 PM CDT Saturday for GMZ631-632-650-
     655-670-675.

&&

$$

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