828
FXUS62 KKEY 310853
AFDKEY

Area Forecast Discussion
National Weather Service Key West FL
453 AM EDT Sun Aug 31 2025

...New DISCUSSION, MARINE, AVIATION...

.DISCUSSION...
Issued at 450 AM EDT Sun Aug 31 2025
Conditions have quieted down across the Florida Keys this morning
after another wave of active wet season weather scraped over the
island chain late last night. What was broken lines of scattered
to numerous showers with embedded thunderstorms is now just
elevated cloud debris gradually dispersing aloft. KAMX radar
detects some of the remains of those showers along with a little
bit of convection pulsing up in the Gulf just north of our waters.
As expected, GOES-19 Nighttime Microphysics shows deteriorating
stratus over the island chain. Current temperature observations
along the Keys report values in the lower 80s with moist dewpoints
in the mid to upper 70s. Meanwhile, gentle to occasionally
moderate southwest to west breezes stubbornly prevail along the
Reef looking like they have fully recovered after last night`s
convective contamination.

The short term forecast is quite similar to what we observed
yesterday. The Keys are currently situated between ridging in the
Caribbean and troughing along the Eastern Seaboard thus allowing
for westerly winds throughout a good chunk of our thermodynamic
profile. Last night`s KKEY 00z balloon sounding confirms this with
westerlies observed from the surface to just before 300 mb. The
sounding also notes a PW of 2.13 inches, just 0.05 inches shy of
the 90th percentile for today, along with an MLCAPE value greater
than 2300 J/kg. It is no wonder why a wave of showers and
thunderstorms was able to proliferate as well as they did. CIMSS
MIMIC TPW shows our area is entrenched in similar PWAT values.
Due to how unchanged our thermodynamic profile and our wind field
is from yesterday, have opted to keep chance showers and
thunderstorms in the short term forecast.

Not much change to the overall pattern and the resulting sensible
weather in the Keys over the next several days. While the trough
along the Eastern Seaboard will shift east into the western North
Atlantic, it is expected to stall out while a surface low develops
off of Georgia`s coastline. While high pressure will build back
into eastern CONUS, the stalled out trough and its surface
reflection will keep Keys breezes westerly until the end of the
week when high pressure finally spreads over mainland Florida. As
little change is currently expected, persistence continues to be
the best forecast with above normal PoPs at 50% along with a
chance of thunderstorms. High and low temperatures will stay near
90 and in the lower 80s (outside of precipitation) respectively as
breezes generally remain out of the west.

&&

.MARINE...
Issued at 450 AM EDT Sun Aug 31 2025
No watches, warnings, or advisories are currently in effect for
the coastal waters of the Florida Keys. From synopsis, somewhat
unusual gentle westerly breezes prevail across the Florida Keys as
our area is situated between ridging in the Caribbean and
troughing along the Eastern Seaboard. This pattern will remain
relatively unchanged throughout the forecast as the trough lazes
over the east coast of CONUS while a surface low develops along
the Georgia coastline. This low is progged to meander off into the
western North Atlantic and rest on the west edge of the Bermuda
High promoting an extension of the already established pattern in
the Keys.

&&

.AVIATION...
(06Z TAFS)
Issued at 450 AM EDT Sun Aug 31 2025
VFR conditions expected to last through this morning. We are
expecting another potentially active period this afternoon with
scattered showers and thunderstorms. However, exact timing and
location remain uncertain and will have to be addressed as
conditions manifest. Outside of convection winds will remain out of
the southwest and west at less than 10 knots.

&&

.CLIMATE...
In 1889, Key West experienced its coldest August ever with an
average temperature of 81.0F in each occurrence.

In 1953, Marathon experienced its coldest August ever, with an
average temperature of 81.9F.

Monthly temperature records for Key West date back to 1872,
and date back to 1950 for Marathon.

&&

.PRELIMINARY POINT TEMPS/POPS...
Key West  92  81  91  81 /  50  40  50  50
Marathon  91  80  90  80 /  50  50  50  50

&&

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

$$

Public/Marine/Fire...JAM
Aviation/Nowcasts....LIW
Data Acquisition.....LIW

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