192
FXUS62 KKEY 311756
AFDKEY

Area Forecast Discussion
National Weather Service Key West FL
156 PM EDT Mon Aug 31 2026

...New AVIATION...

.KEY MESSAGES...

- Chance of showers and thunderstorms expected through tonight
  with the development of a cloud line.

- Mainly light to gentle broadly easterly breezes will continue
  through the first half of the week.

- The Remnants of Dolly remain near Puerto Rico and the Virgin
  Islands and may bring a period of much higher rain chances by
  the middle of the week.

&&

.UPDATE...
Issued at 1135 AM EDT Mon Aug 31 2026
It has been a much quieter morning than this past weekend as some
drier air has filtered in aloft, which has been mostly due to the
influence of upper-level ridging from the SW Atlantic, which will
gradually merge with a strong central CONUS ridge throughout the
day. Despite the influence of this feature, there have been a few
isolated showers attempt to develop but quickly dissipate as
updrafts encounter some of the drier air aloft. However, one
source of initiation that may occur today and has not been a
factor in recent days is the potential for a cloud line to
develop. While the low-level flow is not projected to align in a
completely ideal direction, the boundary layer flow is rather weak
and based on the 12Z KEY RAOB, surface moisture is excellent with
a moist profile from the surface to 950 mb. These factors favor a
much higher cloud line signal with showers and storms likely to
remain near the Island Chain as opposed to displaced given the
lighter flow in place. Given our most recent waterspout index was
calculated at 26%, also can`t rule out some waterspout potential
if surface spin develops in the vicinity of towering cumulus. Any
cloud line activity that develops should fade by the evening but
additional development may occur as outflow boundaries from SWFL
convection spread potentially spread southward into portions of
the area this evening, particularly the Upper Keys and adjacent
marine areas. Otherwise, highs are expected to reach around 90
this afternoon with heat indices peaking around from 105-107 in
most areas.

&&

.DISCUSSION...
Issued at 433 AM EDT Mon Aug 31 2026
CIMSS products continues to show mean layer ridging dominating
much of the Atlantic as well as the ARK-LA-TEX region eastward
through the Southeast U.S. Troughing continues for the West Coast
with more of a zonal flow riding over the top of the ridge across
the Great Lakes and the Northeast U.S. At the surface, the western
side of the high over the Atlantic maintains control across the
Keys. Marine observation platforms surrounding the Island Chain
are recording mainly east breezes of 5 to 10 knots as a result.
GOES 19 Total Precipitable Water (TPW) products shows abundant
moisture across the area with estimated PWATs ranging from 1.85 to
2.4 inches. KBYX radar has remained somewhat active overnight
with a few showers initially across the Upper Keys and the Straits
of Florida to the south of the Lower Keys. However, over the last
hour or two, additional showers developed in the vicinity of the
Dry Tortugas across the SE Gulf while the earlier activity across
the Upper Keys and Straits fizzled out. Temperatures along the
Island Chain are in the lower to mid 80s and dew points are in the
upper 70s to near 80 degrees.

.FORECAST...
Ever so slightly drier air has moved into the Keys early this
morning. Therefore, while we still expect showers and
thunderstorms, we don`t expect the activity to be as widespread
for today and tonight. Therefore, PoPs were lowered slightly to
30% for this frame. The theme remains the overall same though with
an Atlantic ridge continuing to extend its western periphery into
the Keys. Global and numerical model guidance remain in agreement
through at least Tuesday night for a slightly drier period from
today through Tuesday night. The PoPs are as follows 30% tonight,
40% Tuesday, and 30% for Tuesday night. Also, with a slightly
lighter wind regime today, there is the potential that a cloud
line may try to develop during the afternoon, though, this is low
confidence at this time. It may happen again Tuesday afternoon as
well.

With that said, the forecast for mid to late week while still
looking interesting isn`t looking as favorable as it did before.
Global and numerical guidance virtually show the Remnants of Dolly
totally fizzling out as it moves into Cuba. However, the northern
fringe of the moisture associated with it may graze the Keys
Wednesday/Thursday time frame. The remnants and its moisture will
continue moving west northwest gliding along the northern fringe
of Hispaniola and eventually moving right into the eastern side of
Cuba. It appears that the northern fringe of the moisture
associated with Dolly reaches the Keys sometime Wednesday and
continues to affect the region through Thursday/Thursday night
before continuing northwestward into the Gulf. Therefore, likely
Pops are in the forecast for this time frame at 60%. It turns out
the main takeaway for this time frame will be to potentially
expect slightly friskier showers and thunderstorms and an
increase in cloud cover.

Behind the remnants of Dolly, moisture will remain, just not as
deep as the mid to late week time frame. Rain chances return back
to chances (40-50%), though, still remain elevated for late week
and into the holiday weekend. After all, it is September at this
point.

The Keys remain on the western periphery of the Atlantic ridge
through much of the week. This will continue to yield to peaking
and lulling breezes through the middle part of this week. However,
the wind direction will also follow suit with east to southeast
breezes during the early morning to early afternoon hours followed
by northeast to east breezes in the mid to late afternoon into
the early overnight hours. Breezes will stabilize a little bit
more towards the end of the week with mainly east to southeast
light to gentle breezes anticipated. Daytime highs will continue
to be near 90 degrees with overnight lows in the lower to mid 80s,
cooler in and near shower and storms. Dew points will remain
soupy in the mid to upper 70s. September starts in less than 24
hours and Florida will continue to live up to its name for this
time of year with daily rain chances.

TROPICS: The National Hurricane Center (NHC) continues to monitor
two areas for potential tropical cyclone development. The first
is near Puerto Rico and the Virgin Islands (Remnants of Dolly)
which has a low or near 0 percent chance of development through 48
hours and a low or 20 percent chance of development through the
next 7 days. The second area being watched for tropical cyclone
development is currently in the Northern Gulf of America (Invest
97L). This system has a high or 705 chance of tropical development
through both the next 48 hours and 7 days. Both of these systems
currently pose no threat to the Florida Keys, though, Dolly`s
remnants may very well bring an increase in rain chances to the
Keys.

&&

.MARINE...
Issued at 1135 AM EDT Mon Aug 31 2026
There are currently no watches, warnings, or advisories in effect
across the Florida Keys coastal waters. From synopsis, the
western periphery of an Atlantic high remains in control of the
Keys for the next several days. Therefore, expect continued
peaking and lulling breezes. The direction will also shift over
the next few days with east to southeasterly breezes overnight and
in the morning with northeast to east breezes late afternoon and
evening. In addition, the overall flow will keep deep moisture in
place across the region with daily chances of showers and
thunderstorms. Locally hazardous winds and seas are expected in
the vicinity of thunderstorm activity.

&&

.AVIATION...
(18Z TAFS)
Issued at 138 PM EDT Mon Aug 31 2026
Brief light to moderate SHRA may occur through this evening
across portions of the Island Chain due to the development of a
cloud line, which may result in brief flight restrictions at
times. Other than the potential for a few showers through the
remainder of the day, VFR conditions are expected to prevail with
surface winds out of the E around 5 kts through this evening,
gradually shifting to the ESE overnight into Tuesday morning. Some
additional SHRA/TSRA could form late Tuesday morning into the
afternoon, but confidence in overall coverage is low at this time
so this was not included in the recent TAF issuance.

&&

.KEY WATCHES/WARNINGS/ADVISORIES...
FL...None.
GM...None.
&&

$$

Public/Marine/Fire...RG
Aviation/Nowcasts....RG
Data Acquisition.....RG

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