340 
FXUS64 KMOB 301251
AFDMOB

Area Forecast Discussion
National Weather Service Mobile AL
751 AM CDT Mon Aug 30 2021

.AVIATION /30.12Z Issuance/...Conditions across the forecast 
today will primarily be low end MVFR to IFR as a band of heavy 
rainfall associated with Hurricane Ida moves slowly west to east 
across the region. Southeast to south winds from 20 to occasional 
gusts to 30 knots (expecially down near the coast and over the 
western half of the forecast area). Winds will be a little lower 
over the eastern part of the area. /12

&&

.PREV DISCUSSION... /issued 457 AM CDT Mon Aug 30 2021/ 

NEAR TERM UPDATE /Now Through Tuesday/...Ida has been downgraded
to a tropical storm this morning as the core of the system, which
is currently just southwest of McComb MS, is lifting out of LA 
and into MS. Ida will continue to lift north across central MS
today into tonight, then begin to lift northeast into the TN
Valley area by Tuesday afternoon.

As the system lifts north today, a large band of showers and 
storms advecting northward up toward the center of the storm will 
move slowly east across our forecast area today and tonight. 
Training cells along this line will continue to result in the 
threat of heavy rain across the entire area through tonight. With 
that in mind we will maintain the Flash Flood Watch, and earlier 
extended it to cover all counties within our forecast area. Rains
will be likely across most of the forecast area today and tonight,
and then focused more over the eastern portions of the forecast 
area on Tuesday. An additional 6 to 12 inches of rainfall is 
possible over the western half of our forecast area, with isolated
15 inches possible. Over the eastern half of our forecast area 
(which will primarily fall tonight) an additional 4 to 8 inches is
possible. This rainfall, on top of what has already fell and 
saturated grounds will likely result in flash flooding of some 
areas.

There will continue to be some gusty winds across the area today,
particularly in association with the deeper convection that will 
be occurring for most of the day. A Tropical Storm Warning 
continues over our MS counties and three southwestern most AL 
counties through early this morning, but will likely be dropped 
later today. To the east of the Tropical Storm Warning we will 
maintain a Wind Advisory for all of the remainder of our forecast 
area as a moderate southerly flow continues, with stronger gusts 
again near the deeper convection. 

A tornado threat will continue across the entire area today, and
perhaps over the eastern portions of the forecast area on Tuesday.
Any potential tornadoes will be associated with the spiral bands
feeding into Tropical Storm Ida. Latest model guidance suggests strong
low-level shear will remain confined to the eastern semicircle and
there is reason to believe some boundary-layer heating will contribute
to buoyancy from southern LA to the FL Panhandle. Forecast thermodynamic
profiles would yield at least 2500 J/kg MLCAPE with these temperatures
and more robust updrafts can be expected. 

Coastal hazards associated with Ida will continue today as well.
Minor to moderate coastal flooding has been occurring along the
coast of AL and the Mobile Bay area since yesterday afternoon, and
peak water levels associated with the storm will likely occur
early this morning (around daybreak) as we approach astronomical
high tide and the strong, gusty winds become more southerly. In
the northern reaches of Mobile Bay and down along the coast of
Mobile county on the MS Sound, water levels are currently running
between 3 to 3.5 feet above normally dry ground. These water levels
will likely rise a little more to their peak as we reach high 
tide this morning, but will remain above normal levels (and
possibly in the minor flood criteria) at some locations through
the course of the day. Water levels will remain elevated through
mid week as the onshore flow persists, and we will have to monitor
as to whether or not any coastal flood products will need to be
extended further in time. In addition to the coastal flood threat,
a High Surf Warning and High risk of rip currents will continue
early this week as well. 

High temperatures today will be below normal, generally by about 
5 to 10 degrees, ranging from the upper 70s to the lower 80s for
most locations. Lows tonight in the 70s, and then highs on Tuesday
similar to today but warmer by about 6 or 8 degrees. /12 

SHORT TERM /Tuesday night Through Wednesday night/...Conditions
improve across the region during the short term as the remnants of
Ida lift northeast to the mid Atlantic states by Wednesday night.
A trailing trough will be extending back into the southeast from
the remnants, dropping down to the coast by Wednesday night. With
this rain chances will lessen and become more limited to the
southern half of the forecast area as deep later drier air filters
into the region with a sharp upper trough axis over the eastern
third of the country. Nighttime lows Tuesday night and Wednesday
night will be in the upper 60s to lower 70s over inland areas and
low to mid 70s closer to and along the coast. Highs on Wednesday
in the mid to upper 80s. /12 

EXTENDED TERM /Thursday Through Sunday/...The aforementioned upper
trough actually deepens and moves off the east coast Thursday into
the weekend, with high pressure building into the south in its
wake. Deeper moisture is push offshore into the Gulf and a mostly
dry forecast is expected through the extend period except for down
near the coast where slightly better moisture and daily sea 
breezes will result in some isolated convection. Highs each day
will range from the low and mid 80s to the lower 90s across the 
region. Overnight min temps will be quite a bit cooler, with lows
both Thursday night and Friday night in the mid 60s inland and 
lower 70s at the coast. /12

MARINE...High impact marine conditions continue through at least
tonight and likely into midweek as moderate to strong onshore flow
persists as Ida lifts northward away from the marine area. Late in
the week winds and seas steadily subside. /12 

&&

.MOB WATCHES/WARNINGS/ADVISORIES...
AL...Flash Flood Watch through Tuesday morning for ALZ051>060-261>266.

     Tropical Storm Warning for ALZ052-261>266. 

     Wind Advisory until 10 PM CDT this evening for ALZ051-053>060.

     Storm Surge Warning for ALZ263>266. 

     High Rip Current Risk through late Wednesday night for ALZ265-
     266.

     High Surf Warning until 7 AM CDT Tuesday for ALZ265-266.

FL...Flash Flood Watch through Tuesday morning for FLZ201>206.

     Wind Advisory until 10 PM CDT this evening for FLZ201>206.

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

     Coastal Flood Advisory until 7 PM CDT this evening for FLZ202-
     204-206.

     High Surf Warning until 7 AM CDT Tuesday for FLZ202-204-206.

MS...Flash Flood Watch through Tuesday morning for MSZ067-075-076-078-
     079.

     Tropical Storm Warning for MSZ067-075-076-078-079. 

GM...Tropical Storm Warning for GMZ630>633-650-655-670-675. 

     Small Craft Advisory until 9 PM CDT Tuesday for GMZ634>636.

&&

$$

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