872
FXUS62 KKEY 131945
AFDKEY

Area Forecast Discussion
National Weather Service Key West FL
345 PM EDT Thu Jun 13 2024

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

.DISCUSSION...
Issued at 330 PM EDT Thu Jun 13 2024
After very quiet daytime hours yet again today, recent KBYX radar
returns suggest things are quickly changing. Showers and
thunderstorms are approaching our western coastal waters, with
additional activity to the east. It is a bit interesting that
convection has struggled to fire over Cuba today, despite ample
deep, tropical moisture sampled in the CIMSS satellite-derived
total precipitable water product. Temperatures are generally in
the mid to upper 80s across the island chain, with dew points in
the upper 70s.

For tonight, all available mesoscale numerical weather prediction
guidance suggests the convection west of our coastal waters will
sag southeastward this evening. Widespread showers are expected to
continue through much of the overnight hours, with heavy rainfall
being the primary threat. A Flood Watch remains in effect for the
entire Florida Keys island chain through the overnight period.

The stationary front that has remained draped across the Florida
Peninsula for much of the week will remain in place for at least
24 more hours. With a conveyor belt of deep, tropical moisture
continuing, bouts of unsettled weather should continue through
tomorrow, before drier air finally begins to filter across the
Keys for late Friday night through the weekend. The front will be
replaced by a modified continental high that will slide from the
Mid-Atlantic eastward to the western Atlantic for late in the
weekend through early next week. Winds will clock around to the
east and freshen, with an extended period of breezy conditions
expected for this period. Rainfall will be dictated by any
moisture undulations in the easterlies, although in this freshened
flow, at least low-end chance levels of measurable rainfall can
be expected for most periods, especially in the eastern island
communities and marine zones.

There is global numerical weather prediction ensemble support to
suggest a tropical wave may push towards the Keys coastal waters
by the middle to latter part of next week, which may result in an
uptick in rainfall late in the forecast period. With increased
sunshine expected for the weekend through much of next week,
temperatures should moderate to near normal, with highs near 90F,
and lows in the lower 80s.

&

.MARINE...
Issued at 330 PM EDT Thu Jun 13 2024
Small Craft Should Exercise Caution headlines posted for the
western marine zones south of the Lower Keys, including western
Hawk Channel and the western Straits of Florida. Scattered showers
and thunderstorms are expected to increase in coverage and
intensity over the next several hours. Heavy rainfall, gusty winds
and confused seas, and cloud to surface lightning strikes will be
possible with any stronger storm. From synopsis, the pattern for
the remainder of the week will feature weak high pressure over the
western North Atlantic and a frontal boundary stalled over
northern Florida. However, the main weather maker will be a large
cyclonic system centered over Central America. Mainly moderate
breezes and an extended period of unsettled weather featuring
thundery squalls will persist tonight through Friday night. Rain
and thunder chances will decrease gradually starting Saturday.
Breezes will freshen by Sunday night, with moderate to fresh
easterly breezes expected for late in the weekend into early next
week.

&&

.AVIATION...
(18Z TAFS)
Issued at 330 PM EDT Thu Jun 13 2024
VFR conditions will mainly prevail through approximately 22Z, but
showers and thunderstorms similar to yesterday will approach both
terminals and push through during the late afternoon and evening
hours. Intermittent periods of MVFR or even IFR conditions are
possible due to fluctuations in CIGs and VIS. VCSH is in the
forecast at 22Z, and changes over to VCTS at 22Z, but there are
still no TEMPO groups for category changes due to uncertainty with
respect to timing. Near-surface winds will overall remain southerly,
but become variable when the showers and thunderstorms move
through.

&&

.PRELIMINARY POINT TEMPS/POPS...
Key West  77  88  79  90 /  80  70  50  40
Marathon  77  88  79  89 /  80  70  50  40

&&

.KEY WATCHES/WARNINGS/ADVISORIES...
FL...Flood Watch through late tonight for FLZ076>078.

GM...Small Craft Advisory until 5 PM EDT this afternoon for GMZ044-
     054-055-074-075.

&&

$$

Public/Marine/Fire...BT
Aviation/Nowcasts....DP
Data Acquisition.....11

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