Area Forecast Discussion
Issued by NWS Key West, FL

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851
FXUS62 KKEY 171914
AFDKEY

Area Forecast Discussion
National Weather Service Key West FL
314 PM EDT Tue Sep 17 2024

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

.DISCUSSION...
Issued at 300 PM EDT Tue Sep 17 2024

A very wet weather pattern remains planted across the broader
area. This is due to a stalled old frontal zone across the Florida
Peninsula and a deep layered nearly cut off low centered over the
southeastern United States. Precipitable water has been elevated
across our area for a while and these features, if anything, are
contributing to keeping the atmosphere wet. This mornings
sounding also indicated ample CAPE. The lower tropospheric ridge
is aligned near and just south of the Keys and is providing some
lower level confluence. Perhaps the main negative for convective
initiation is the lack of a well defined flow through the lowest
levels. This is due to a weak low off the centered roughly over
the Mid Atlantic. No significant changes are expected to the
overall synoptic scale makeup. The environment will remain quite
conducive for rounds of showers and thunderstorms. Will maintain
likely pops for at least the next 24 hours.

While there is some uncertainty, guidance has been hinting at the
mid and upper level support will lessen and the lower levels will
lose some confluence. For now, will maintain the transition to mid
chance pops. Of note, is the old low near the Mid Atlantic will
continue to meander off the coast and gradually strengthen and
begin slipping southeast to southward as it interacts with the
upper trough later in the week. All this may result in synoptic
rain chances slipping due to the diminishing moisture and less
forcing at both the lower and upper levels. However, it would
better open the door for mainland activity moving south to
southwestward into the Keys.

&&

.MARINE...
Issued at 300 PM EDT Tue Sep 17 2024
A weak low pressure system will meander off the Atlantic coast
over the next several of days. This low will then deepen as it
interacts with an upper low as it meanders southeast to southward.
As a result, the usual western flank of the Atlantic ridge will
be disrupted, leading to light and often variable through the
duration of the forecast.

&&

.AVIATION...
(18Z TAFS)
Issued at 300 PM EDT Tue Sep 17 2024

Shower activity is starting to diminish at both EYW and MTH. VCSH
shower is still included for the lingering showers but will be
removed once those dissipate. Near surface winds will be east to
southeast at 5 to 10 knots.

&&

.KEY WATCHES/WARNINGS/ADVISORIES...
FL...Coastal Flood Advisory FLZ076.
GM...None.

&&

$$

Public/Marine/Fire...11
Aviation/Nowcasts....AP
Data Acquisition.....AP

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