Lower Sugarloaf Key, Florida Weather Forecast Discussion

380
FXUS62 KKEY 071727
AFDKEY
Area Forecast Discussion
National Weather Service Key West FL
127 PM EDT Sun Sep 7 2025
...New AVIATION...
.AVIATION...
(18Z TAFS)
Issued at 127 PM EDT Sun Sep 7 2025
VFR conditions will prevail at both EYW and MTH through the TAF
period. While shower activity is limited for the time being, pop
up showers could cross either terminal later this evening, VCSH
will be added if showers start to develop. Near surface winds
will be light and variable but mainly southerly.
&&
.PREVIOUS DISCUSSION...
Issued at 1100 AM EDT Sun Sep 7 2025
Finally getting to see some SUN on this SUNday for the Florida
Keys. Unlike the last few days, KBYX radar remains mostly quiet
outside of a few stray light showers in the area. This morning`s
12z KKEY sounding did sample ample moisture in the atmosphere but
in comparison to what values we have been measuring it is lower.
MIMIC Precipitable Water does reveal we still are in a very moist
environment as well. Along the island chain, temperatures are in
the mid 80s with the Reef recording southwest winds of 5 to 10
knots. The lack of showers this morning could change as the day
progresses due to boundaries moving around the CWA that are just
dormant for the time being so did not make any adjustments to the
current PoPs of 50%. Outside of any shower development conditions
will be pleasant with highs in the Upper 80s and south to
southwest winds at 5 to 10 knots. No changes were necessary to
this update package.
&&
.FORECAST...
Issued at 400 AM EDT Sun Sep 7 2025
Weak surface through lower level troughing remains dug in over
the eastern Gulf and Florida. This along with an early season mid
latitude trough blanketing the eastern United States has
contributed to a persistent band of very high precipitable water
and weak lower level confluence across our region. While the setup
is not as primed as it was for much of last week, shower and
thunderstorm chances remain above seasonal normals. After a fairly
quiet late evening in the Keys, widely scattered showers have
begun bubbling over the Florida Straits and deep Gulf zones.
Unfortunately, little change to the overall weather pattern is
projected for the next few days. Troughing will remain to our
north across the Gulf and the Florida Peninsula while the Atlantic
ridge will ebb and flow across the Bahamas and Cuba. This will
maintain a broad confluence zone across our area and the swath of
very high precipitable water is not going anywhere. As a result,
expect continued above normal rain chances for this time of year.
The steering flow will remain rather weak, relegating convective
initiation and inhibition to mesoscale factors such as day time
heating, Cuban shadow, and island cloud line build up.
Heading into mid week, the Atlantic ridge will attempt a push
across Cuba and towards the Yucatan as much of the festering
surface trough is vacuumed northeastward by the mid latitude
trough. However, an incoming shortwave trough aloft will
obliterate the Atlantic ridge`s salient, and help to establish
weak lower level troughing across Florida and the Keys.
Consequently, steering currents will be weak, moisture will remain
high, as will rain chances.
&&
.MARINE...
Issued at 1100 AM EDT Sun Sep 7 2025
A Coastal Flood Statement is in effect for the Upper Keys waters
as minor saltwater flooding of low elevation streets and lots is
likely. Beyond that, no watches, warnings, or advisories are in
effect for the Florida Keys. From synopsis, a surface trough will
remain centered over the eastern Gulf and Florida Peninsula well
into the week. This trough will finally wash out heading into mid
week. However, the pressure field in and around the Keys will
remain poorly defined. Continued very high moisture levels and
weak steering currents will generally result in greater convective
coverage through the forecast.
&&
.KEY WATCHES/WARNINGS/ADVISORIES...
FL...None.
GM...None.
&&
$$
Public/Marine/Fire...AP
Aviation/Nowcasts....AP
Data Acquisition.....DP
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NWS KEY Office Area Forecast Discussion