Area Forecast Discussion
Issued by NWS Mobile, AL

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FXUS64 KMOB 121016

Area Forecast Discussion
National Weather Service Mobile AL
516 AM CDT Sat Jun 12 2021

.NEAR TERM UPDATE /Now Through Sunday/...Northwest flow aloft
continues today as the forecast area remains in between an upper
level ridge to the west and an upper level trough to the east. A
weak surface boundary moves across the area today in association
with the upper level trough and developing surface low to our
east, shifting surface winds from westerly to northwesterly. This
surface boundary hangs around during the near term and will be the
source for convective development across the area. Scattered to
numerous showers and thunderstorms are expected both today and
Sunday, with the greatest coverage occurring today. A very moist
and unstable environment can be expected ahead of the surface
boundary with PWAT`s ranging from 1.7 to 2 inches. CAPE values
approaching 3000 to 3500J/Kg in combination with the surface
boundary help support wet microburst potential across the area
today. Most of the forecast area is included in a Marginal Risk
this afternoon and evening with the potential for isolated strong
to severe storms. Damaging wind gusts, heavy rain, and frequent
lightning will be the main hazards with these storms.

By Sunday, the upper level ridge shifts just slightly west causing
upper level flow to become northeasterly. Surface winds remain
generally northwest with the surface boundary still located over the
forecast area. Therefore, scattered to numerous storms can be
expected again on Sunday.

Temperatures across the area will generally be in the upper 80s to
low 90s today and will warm slightly on Sunday to the lower to mid
90s. Heat indices of 100 to 105 are possible this weekend. Lows
will be in the low to mid 70s inland to upper 70s along the coast.


.SHORT TERM /Sunday night Through Monday night/...A mid to upper
level trough slowly progresses south and east of the area Sunday
night into Monday as the ridge centered over the Four Corners region
begins to build east somewhat. Northerly to northeasterly (at times)
winds aloft persist through the short term as the trough gets nudged
out of the forecast area. Drier air on the backside of the mid level
trough filters into much of Deep South on Monday, except right along
the Gulf Coast. Down in the lower levels, the local area remains on
the western periphery of a weak surface trough sliding through the
Southeast while a weak surface ridge encompasses much of the Gulf.
Moisture in the lower levels lingers across much of the area through
Monday night. PWATs finally begin to trend downward by early Tuesday
morning as a decent moisture gradient sets up across the area with
1.3-1.5 inch PWATs across inland communities and 1.6-1.9 inch PWATs
across the coastal counties.

Showers and storms will likely still be ongoing as we head into the
Sunday night timeframe, but will dwindle in coverage throughout the
evening hours. Temperatures overnight will only fall into the mid to
low 70s areawide. By Monday, temperatures will soar into the mid to
low 90s. Dewpoints will unfortunately remain in the 70s on Monday,
so heat indices will creep back up into the 102-107 range. Storm
coverage on Monday will not be quite as high as what we will see
over the weekend, but there will still be scattered showers and
storms throughout the afternoon given the lingering surface trough
and ample moisture. Overnight lows will almost be a carbon copy of
Sunday night`s temperatures, but a few spots north of the Highway 84
corridor might fall into the upper 60s. 07/mb


.EXTENDED TERM /Tuesday Through Friday/...Through the extended, the
upper ridge over the western CONUS and upper trough over the east
coast will largely prevail. Expecting a typical, summertime diurnal
pattern through midweek, with daily chances of showers and storms
developing over the Gulf and along the coast in the morning
spreading inland through the day. However, by late week, models are
indicating a disturbance entering the Gulf of Mexico, bringing a
plethora of moisture along with it to the northern Gulf coast.
Although, the GFS looks to be slower with this feature moving north
over the Gulf coast than the ECMWF at this point. As the previous
shift stated, we will monitor this as the forecast for late next
week will depend on how this disturbance develops. For example,
there could be a big increase in PoPs and associated heavy rain
potential as model PWATs increase to be between 2.5-3.0 inches along
the Gulf coast. However, it is still too early to know exactly when
and where this might occur. Otherwise, a mainly diurnal summertime
convective pattern could win out for late week. For now, stuck close
to the PoPs given by the Blend, but did keep chances below likely
due to model uncertainty and this being at the tail end of the
forecast period.

Tuesday will be warm, as high temperatures top out in the lower to
mid 90s (upper 80s at the beaches). With ample moisture present,
heat indices will be in the upper 90s to lower 100s. Through
Wednesday and Thursday, highs will be a touch cooler, with
temperatures in the upper 80s to around 90 degrees (mid 80s at the
beaches). Models indicate a fairly decent decrease in temperatures
by Friday (compared to Tuesday), due to the potential for increased
chances of rain. Highs are anticipated to generally be in the mid
80s. Lows will mainly be in the upper 60s to lower 70s north of I-10
and in the lower to mid 70s south through the period. /26/12


.MARINE...Small Craft Exercise Caution conditions are expected
today with westerly winds elevated between 15 and 20 knots with
occasional higher gusts mainly over the open Gulf waters and
including Lower Mobile Bay and the Mississippi Sound. /14




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