818
FXUS62 KKEY 181859
AFDKEY

Area Forecast Discussion
National Weather Service Key West FL
259 PM EDT Mon Aug 18 2025

...New AVIATION, MARINE...

.AVIATION...
(18Z TAFS)
Issued at 300 PM EDT Mon Aug 18 2025
VFR conditions will prevail for the rest of the day and into
tonight. A passing shower or two cannot be ruled out especially
near MTH where storms may descend south from mainland Florida.
However, VCSH is not mentioned in either TAF due to low confidence
of occurence and exact timing of still developing precipitation.
Near surface winds will be light and generally out of the
northwest to north.

&&

.PREVIOUS DISCUSSION...
Issued at 1115 AM EDT Mon Aug 18 2025
A fairly calm and clear day is underway across the Florida Keys.
Following a few specks of shallow nocturnal showers this morning,
KBYX is currently free of any precipitable echoes in our area,
minus one shower over the Marquesas Keys. Even GOES-19 visible
imagery is showing mostly clear skies over the island chain and
its nearshore waters with only a cluster of fair weather cu here
and there. Some clouds have started building more recently over
the Lower Keys, but nothing stands out from the crowd just yet.
Temperatures are already approaching near 90 across the Keys as a
result. This along with light and variable winds, is making it
feel like a somewhat typical summer day.

What is not too normal about today is the surrounding synoptic
features. A col region is currently over the Keys promoting light
and variable breezes between deep ridging over southeast CONUS
and Hurricane Erin currently located 110 miles north of Grand Turk
Island. Over the short term forecast, Erin is progged to continue
northwest passing to the east of the Bahamas keeping the Florida
Keys from any direct impacts. It will, however, still have
somewhat of a pull on our sensible weather. CIMSS MIMIC Layer TPW
shows that the dry slot in front of Erin is currently over our
area. This morning`s KKEY 12z sounding measured a PW of 1.65
inches which is just below the 25th percentile. This notably dry
layer found in the lower to mid levels of the sounding will hinder
convective development around our CWA today. The best chance for
rain today, if any, will be from mainland South Florida once their
usual round of afternoon convection builds up and our winds shift
to be out of the northwest to north due to Erin`s influence. Thus
have elected to lower PoPs to slight chance for this afternoon
yet still just above recent guidance considering the time of year.

&&

.FORECAST...
Issued at 427 AM EDT Mon Aug 18 2025
While Hurricane Erin is not expected to cause any direct impacts
to the Florida Keys, synoptically it will be the main feature for
the next few days. As Erin moves northerly far to our east, winds
will be northwest and eventually westerly which is not typical
for our CWA. This won`t last long as the system continues to move
further from the US. Then synoptic influences will lack in the
region and winds will shift back to their easterly direction and
rain chances will remain near normal. Stay tuned for any updates.

&&

.MARINE...
Issued at 300 PM EDT Mon Aug 18 2025
No watches, warnings, or advisories are currently in effect for
the coastal waters of the Florida Keys. From synopsis, the Keys
are in a col region between ridging over the southeast US and
Hurricane Erin in the western North Atlantic resulting in now
light to gentle northwest to northerly breezes across our waters.
As Hurricane Erin makes its closest point of approach east of The
Bahamas, breezes will veer to the northwest to north and freshen
by tonight before gradually backing to the south by the end of the
week.

&&

.PRELIMINARY POINT TEMPS/POPS...
Key West  82  93  82  92 /  30  30  40  30
Marathon  82  91  82  91 /  30  30  30  30

&&

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

$$

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

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