Excessive Heat Warning 1, NWS Mobile, AL

Area Forecast Discussion
National Weather Service Mobile AL
324 PM CDT Fri Aug 16 2024

...New NEAR TERM, SHORT TERM, LONG TERM, MARINE...

.NEAR TERM...
(Now through Saturday)
Issued at 324 PM CDT Fri Aug 16 2024

Visible satellite imagery this afternoon reveals a decent cumulus
field across the area. Isolated showers and a few thunderstorms are
beginning to develop along the sea-breeze and in areas along and
west of I-65 where PWATs are around 2 inches. This coverage should
gradually become more scattered as we head later into the afternoon
and early evening hours with storms initiating along outflow
boundaries. Storm will generally move to the south/southeast thanks
to a north/northwest flow aloft. A few of these storms could becomes
strong or marginally severe with gusty winds and frequent lightning
being the main concerns given that DCAPE values are in excess of
1000 J/Kg. In the lower levels, a surface ridge of high pressure is
lingering over portions of south central Alabama and the Florida
Panhandle which is helping to limit convective activity in these
areas. Outside of the developing showers and storms, it's been
rather hot today. Current temperatures are in the lower and middle
90s with few areas in the upper 90s. A Heat Advisory remains in
effect for all of southeast Mississippi and portions of southwest
Alabama through early this evening where heat index values of 108 to
110 are being reached. There may be a few lingering showers and
storms through early this evening over northwestern portions of the
area, but otherwise, conditions will be mostly dry tonight. Low
temperatures will fall into the lower 70s over south central
Alabama, the middle 70s across southeast Mississippi and southwest
Alabama, and the lower 80s at the beaches.

The upper level pattern will begin to change on Saturday as upper
level ridging retreats westward and an upper low, centered over the
Great Lakes region, digs down into the Southeastern US. This will
place the area within a northwest flow aloft by Saturday evening
with plenty of deep layer moisture in place. Another round of
showers and storms is expected to develop on Saturday with some
guidance indicating the potential of an MCS moving along an outflow
and into northern portions of the area Saturday evening. There is
still quite a bit of uncertainty as to whether or not storms will
be able to cluster together into an MCS and eventually move into our
area, so for now I have maintained scattered PoPs across our
interior areas for late Saturday. If the MCS is able to develop, we
could see an isolated strong wind gust in these northern zones given
that there will be plenty of instability and mid level dry air.
Temperatures will still be hot before storms develop with high
temperatures rising into the middle and upper 90s again Saturday
afternoon. Dew points will also be on the rise as boundary layer
moisture improves which will result in heat index values of 105-112
degrees with the highest values occurring over western portions of
the area. Another Heat Advisory has been issued for southeast
Mississippi, southwest Alabama, and portions of south central
Alabama.  It's possible the advisory may need to be expanded further
east, but confidence was not high enough to do so this afternoon.
/14

&&

.SHORT TERM...
(Saturday night through Monday night)
Issued at 324 PM CDT Fri Aug 16 2024

An upper trof amplifies significantly over the eastern states
through the period, with an associated surface low well to the
north bringing a modest cold front down through the forecast area
during Sunday afternoon into the overnight hours. This pattern
will promote a northwesterly steering flow in which convection
could develop upstream and move into or through a portion of the
area Saturday evening and also accompany the frontal passage
Sunday afternoon into Sunday night. There is a possibility that
the convection could evolve into an MCS, but shear values will
remain rather low making the potential development unclear. Plenty
of deep layer moisture looks to be in place over the area ahead
of the approaching front before much drier air filters into the
region in the wake of the frontal passage. MLCAPE values on Sunday
could reach near 3000 J/kg along with DCAPE values around 1500
J/kg, which portends strong storms with the potential for some
pulse-type severe storm development. SPC has included much of the
area in a marginal risk mainly for Sunday afternoon into Sunday
evening due to this environment. Have gone with slight chance to
chance pops for much of the area Saturday evening, then chance
pops follow for the entire area on Sunday into Sunday night. Will
have low end pops over the southern portion of the area on Monday,
but otherwise dry conditions prevail into Monday night. Lows
Saturday night and Sunday night range from the lower 70s inland to
the upper 70s/near 80 at the coast. Low Monday night will be
somewhat cooler and range from the mid 60s well inland to the mid
70s at the coast. Highs on Sunday range from the mid 90s to 100,
and heat index values look to attain Heat Advisory criteria of
108+ for essentially the entire area, and there's the potential
that portions of southeast Mississippi and southwestern Alabama
may reach Excessive Heat Watch/Warning criteria of 113. Per
coordination with adjacent offices, will defer to the next shift
for issuance consideration. Highs on Monday will be mostly in the
lower to mid 90s and heat index values for the most part look to
remain below heat advisory criteria, but it's possible that
another Heat Advisory could become necessary for the immediate
coast. A low risk of rip currents is expected during the period.
/29

&&

.LONG TERM...
(Tuesday through Friday)
Issued at 324 PM CDT Fri Aug 16 2024

Dry conditions are expected over the area Tuesday and Wednesday as
the large eastern states upper trof keeps drier air in place over
the region in the wake of the frontal passage in the SHORT TERM
period. The upper trof weakens on Thursday though manages to
maintain a "weakness" over the region into Friday between a
central states upper ridge and a western Atlantic upper ridge.
Deep layer moisture recovers substantially late in the week, so
will have slight chance to chance pops return to the forecast on
Thursday and Friday. /29

&&

.MARINE...
Issued at 324 PM CDT Fri Aug 16 2024

No impacts are expected outside of locally higher winds and seas
near thunderstorms. A light to occasionally moderate onshore flow
continues through the weekend. A surface boundary will then move
over the Gulf on Monday and winds turn northerly in the wake. A
light diurnal pattern then returns by the middle of the week. /14

&&

.PRELIMINARY POINT TEMPS/POPS...
Mobile      76  95  76  98  75  96  72  95 /  10  20  10  30  50  20  10  10
Pensacola   78  95  79  97  78  96  75  95 /   0  20  10  40  50  30  10  10
Destin      79  93  80  94  79  95  76  94 /   0  20  20  40  50  30  10  10
Evergreen   72  97  73  97  72  93  67  93 /  10  30  30  40  50  10   0   0
Waynesboro  74  97  73 100  72  94  68  92 /  20  40  20  30  40  10   0   0
Camden      73  95  73  96  71  91  67  90 /  10  40  30  40  40   0   0   0
Crestview   72  97  74  97  74  96  69  96 /   0  20  20  40  50  20   0   0

&&

.MOB WATCHES/WARNINGS/ADVISORIES...
AL...Heat Advisory until 7 PM CDT this evening for ALZ051-052-261-263-
     265.

     Heat Advisory from 10 AM to 7 PM CDT Saturday for ALZ051>053-
     261>266.

FL...None.
MS...Heat Advisory until 7 PM CDT this evening for MSZ067-075-076-078-
     079.

     Heat Advisory from 10 AM to 7 PM CDT Saturday for MSZ067-075-076-
     078-079.

GM...None.
&&

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