Area Forecast Discussion
Issued by NWS Key West, FL

Home |  Current Version |  Previous Version |  Text Only |  Print | Product List |  Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28
659
FXUS62 KKEY 171856
AFDKEY

Area Forecast Discussion
National Weather Service Key West FL
256 PM EDT Mon Jun 17 2024

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

.DISCUSSION...
Issued at 256 PM EDT Mon Jun 17 2024

We have returned to a more normal summertime regime today.
Easterly winds have increased a few knots over the past couple of
hours, and has started to pump in increased moisture across the
area. Some light showers have begun to develop within the easterly
flow. Otherwise, partly cloudy skies are being seen across the
Florida Keys this afternoon. With more abundant sunshine today,
temperatures have been able to reach near 90 degrees and dew
points in the mid to upper 70s. Luckily, the higher winds are
keeping some of the humidity at bay, but with these toasty summertime
temperatures, it is still hard to stay cool outside.

The main weather story this week will be the winds. High pressure
centered off the Northeast coast and an expansive low (Central
American Gyre) located across the Yucatan Peninsula will be the
two features promoting these breezy conditions. The high will
slowly sink southward through the week, while the broad low will
slowly meander around in the same general area. The placement of
these two features will maintain elevated winds through the end of
the work week.

Outside of the wind forecast, things are a little less clear-cut.
The aforementioned CAG will spit out a disturbance, which will
bring heavy rainfall to the western Gulf Coast and Texas. At the
same time, an inverted trough riding along in the easterlies is
forecast to develop some type of surface reflection by mid-week.
An upper-level low associated with this feature may take a
different course than the surface low and push across our area
into the Gulf of Mexico while the weak surface low is expected to
move ashore somewhere along the Southeast coast. What does this
all mean for the Florida Keys? The exact trajectory of all of
these features could influence the amount of moisture across our
neck of the woods, the overall wind forecast late in the week,
and the amount of upper-level support. MOS guidance is suggesting
a wetter latter half of the week, but due to some of the
uncertainties regarding the trajectory of the moisture and upper-
level support, have capped PoPs at high end chance (40-50%)
through the extended forecast. As confidence increases over the
next few forecast cycles and we can more definitively narrow down
the wettest periods, an increase in rain chances for a few days
could be necessary. If the trend of the upper-low moving over our
area continues, we also may need to increase thunder chances for
a few forecast periods. Regardless, strong easterly flow will
direct moisture across the region and just this by itself is
likely enough to spur on above normal rain chances during the wet
season. On top of the stronger flow, confluent flow in between the
high in the Atlantic and the low near the Yucatan will also aid
in yielding above normal rain chances for the next few days.
Temperatures through the extended forecast will remain seasonable,
with highs reaching near 90 degrees and lows dropping only as far
as the lower 80s each day outside of any rain-cooled air.

&&

.MARINE...
Issued at 256 PM EDT Mon Jun 17 2024

A Small Craft Advisory is in effect for the Florida Keys coastal
waters. From synopsis, strong surface high pressure centered off
the New England coast working in tandem with falling pressures
over the Yucatan Peninsula and the Bay of Campeche is expected to
result in moderate to fresh breezes tonight through mid week. An
area of low pressure may develop mid week a few hundred miles
north of the central Bahamas towards mid week and move towards the
north to central Florida coastline. This may result in a brief
slackening of breezes before high pressure takes control again
resulting in freshening east to southeasterly breezes late week.

&&

.AVIATION...
(18Z TAFS)
Issued at 256 PM EDT Mon Jun 17 2024

VFR conditions will prevail at both EYW and MTH through the TAF
period. KBYX radar shows some light showers/sprinkles moving into
the Upper Keys which were moving to the southwest to west near 10
knots. The timing and placement of these showers remains uncertain
for both terminals, therefore, VCSH was left out of the TAF for now.
Near surface winds will be mainly east near 15 knots with frequent
gusts to near 25 knots.

&&

.CLIMATE...
On this day in 1972, the daily record high temperature of 99F was
recorded in Marathon. This is also the hottest temperature ever
recorded in the month of June, and ties July 15th, 1987 for the
hottest temperature ever recorded in the Marathon area. Temperature
records for Marathon dates back to 1950.

&&

.PRELIMINARY POINT TEMPS/POPS...
Key West  83  89  82  89 /  30  40  30  40
Marathon  82  90  82  90 /  30  30  30  40

&&

.KEY WATCHES/WARNINGS/ADVISORIES...
FL...None.
GM...Small Craft Advisory for GMZ031>035-042>044-052>055-072>075.

&&

$$

Public/Marine/Fire...NB
Aviation/Nowcasts....MJV
Data Acquisition.....DR

Visit us on the web at weather.gov/key

Follow us on Facebook and Twitter at:
www.facebook.com/nwskeywest
www.twitter.com/nwskeywest