Excessive Heat in Florida, August 11 to 15, 2023

Area Forecast Discussion
National Weather Service Tallahassee FL
555 AM EDT Fri Aug 11 2023

...New AVIATION...

.NEAR TERM...
(Today and tonight)
Issued at 352 AM EDT Fri Aug 11 2023

There are a couple of hazards to discuss today, heat and the
potential for severe weather this afternoon. The heat has been
relentless for several days, and it will continue today with at
least advisory criteria (108-112 heat index) over a large portion of
the area. Looking at obs yesterday, the TLH ASOS heat index peaked
at 114, and several RAWS sites across the Florida big bend also
exceeded excessive heat warning criteria at 113 or higher. Given
that similar conditions today are expected, we have upgraded to
another excessive heat warning for portions of the big bend and
panhandle this afternoon.

Farther to the north, the forecast gets trickier as a cluster of
thunderstorms will likely develop northwest of the area and push
into the northern forecast area this afternoon. This will likely
keep peak heat index values a little lower to the north. Looking at
forecast soundings, the threat for severe weather is certainly there
with any storms that organize. A strongly unstable environment is
expected with MLCAPE of 3000-4000 j/kg with favorable DCAPE over
1000 j/kg. In addition, deep layer shear of 15-20 knots could allow
for a few clusters of storms to organize. Damaging wind is the main
threat with these storms this afternoon, and a mention of gusty
winds with thunderstorms was added to the point and click forecast
for the northern portions of the area.

Actual high temperatures are expected to range from the low to mid
90s across the far northern areas to the mid to upper 90s elsewhere.
Overnight lows will also continue on the warm side tonight with mid
70s for most of the area and near 80 along the coast.

&&

.SHORT TERM...
(Saturday through Sunday night)
Issued at 352 AM EDT Fri Aug 11 2023

Upper level ridge builds over the southern US over the weekend with
hot temperatures expected to continue. Mid-level flow will be out
of the north so the greater coverage of showers and storms is
expected to be across our Florida counties with chances tapering
off to around 20-30% across Georgia and southeast Alabama. The
main story over the weekend will be the heat. With rain chances
dropping off somewhat compared to Friday, that should allow plenty
of sunshine through the morning and afternoon. With abundant low-
level moisture in place and widespread temperatures in the upper
90s and around 100, excessive heat is likely again.

In what continues to be an above-normal, and extremely humid
summer, heat indices on Saturday/Sunday will rival those we
observed this previous Monday. Current forecast heat indices show
widespread values around 115 to 120 in Florida counties in and
west of Tallahassee with some isolated locations possibly
observing heat indices near 122 on Saturday. Other locations
across southeast Alabama and into extreme southern Georgia and the
Big Bend will see heat indices around 113 to 118 on Saturday
afternoon. The hot temperatures continue again into Sunday where
another round of excessive heat is likely as heat indices climb
into the 114-119 range on Sunday. Rain chances drop off slightly
on Sunday as drier air filters in and chances range from 30 to 50%
across Florida to 10-30% across Alabama/Georgia.

&&

.LONG TERM...
(Monday through Thursday)
Issued at 352 AM EDT Fri Aug 11 2023

The heat continues through the beginning of the week as the upper
level ridge remains overhead. This ridge should slowly weaken as
west/northwest flow aloft redevelops across the southeast parts
of the US through the week. This pattern should help bring a weak
frontal boundary into the forecast area which will increase rain
chances slowly through the week and bring a slow decrease in heat
indices.

&&

.AVIATION...
(12Z TAFS)
Issued at 555 AM EDT Fri Aug 11 2023

Other than some isolated and brief pockets of low ceilings early
this morning, VFR conditions are expected to prevail through the
morning. For this afternoon, scattered showers and thunderstorms are
expected to develop and become most numerous across portions of
southwest Georgia, including ABY. Gusty winds are possible with the
storms this afternoon, and a few may be severe.

&&

.MARINE...
Issued at 352 AM EDT Fri Aug 11 2023

Light west to southwest flow will prevail through the period.
Scattered showers and storms are expected with coverage gradually
increasing each day beginning Monday. Best coverage for storms
will be in the overnight and morning hours. Seas will remain
around 1 to 2 feet.

&&

.FIRE WEATHER...
Issued at 352 AM EDT Fri Aug 11 2023

Hot conditions will continue for the next several days with
dangerously high heat index values in the afternoon. Scattered
showers and thunderstorms are also expected. Gusty and erratic winds
and frequent lightning are possible near and within thunderstorms.

&&

.HYDROLOGY...
Issued at 352 AM EDT Fri Aug 11 2023

Rainfall amounts will generally be around 1 inch through the next
5 days. Isolated higher amounts of 1 to 3 inches are possible
under slower moving storms. No flooding concerns are expected.

&&

.SPOTTER INFORMATION STATEMENT...

Spotter activation is not requested. However, spotters are always
encouraged to safely report significant weather conditions when they
occur by calling the office or tweeting us @NWSTallahassee.

&&

.PRELIMINARY POINT TEMPS/POPS...
Tallahassee   97  77  98  78 /  50  40  50  10
Panama City   92  82  94  81 /  30  20  50  20
Dothan        96  76  98  76 /  50  30  40  10
Albany        93  75  97  76 /  70  50  20  10
Valdosta      96  76  97  76 /  40  50  30  10
Cross City    95  78  96  77 /  20  20  50  20
Apalachicola  92  82  93  81 /  30  20  40  20

&&

.TAE WATCHES/WARNINGS/ADVISORIES...
FL...Heat Advisory from 11 AM this morning to 8 PM EDT this evening
     for FLZ019-028-029-034-128-134.

     Excessive Heat Watch from Saturday morning through Saturday
     evening for FLZ007>019-026>029-034-108-112-114-115-118-127-
     128-134.

     Excessive Heat Warning from 11 AM EDT /10 AM CDT/ this morning
     to 8 PM EDT /7 PM CDT/ this evening for FLZ007>018-026-027-
     108-112-114-115-118-127.

     High Rip Current Risk through this evening for FLZ108-112-114.

GA...Heat Advisory from 11 AM this morning to 8 PM EDT this evening
     for GAZ142>148-155>161.

     Excessive Heat Watch from Saturday morning through Saturday
     evening for GAZ155>160.

AL...Heat Advisory from 10 AM this morning to 7 PM CDT this evening
     for ALZ065>069.

     Excessive Heat Watch from Saturday morning through Saturday
     evening for ALZ065>069.

GM...None.
&&

NEAR TERM...DVD
SHORT TERM...Dobbs
LONG TERM....Dobbs
AVIATION...DVD
MARINE...Dobbs
FIRE WEATHER...DVD
HYDROLOGY...Dobbs