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000
FXUS62 KKEY 220840
AFDKEY

Area Forecast Discussion
National Weather Service Key West FL
440 AM EDT Mon Apr 22 2024

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

.DISCUSSION...
Issued at 440 AM EDT Mon Apr 22 2024

Mostly clear, mild and dry conditions prevail along the Florida
Keys on this early Monday morning. KBYX radar detects a narrow line
of showers and thunderstorms over the Gulf of Mexico about 150
miles NW of Key West, just ahead of an advancing cold front.
Temperatures along the island chain range from the mid to upper
70s at most locations, to the mid 60s at the typical island
interior cold spot at North Big Pine RAWS. Light and variable
winds earlier in the night have become S/SW at 5 to 10 knots
recently, as the surface ridge is pushed south and east of our
area by the approaching front. Surface analysis depicts the
aforementioned front extending from the western Atlantic across
central Florida and into the SE Gulf, with a large high pressure
area behind the front sprawling from the Southern Plains to the
Mid Atlantic states. Aloft, the lower-mid level ridge which has
controlled our weather for the past several days has been shoved
SW to near the Yucatan Peninsula, as a well-defined shortwave
trough moves eastward across the Southeastern states. The 00Z Key
West sounding remained dry and stable, with a low/strong inversion
based near 2000 feet, PW of 1.22 inches, and very dry air
throughout the lower/mid levels above the inversion. More recent
MIMIC-TPW satellite imagery shows a fairly narrow stripe of higher
PWs along the advancing front, with estimated PWs up to 1.7
inches.

The cold front will continue pushing steadily to the SE today, and
is expected to pass through the Keys this afternoon. The front
will be moving into an increasingly unfavorable environment across
most of the Keys, and CAM/MOS guidance remains in good agreement
that the shower activity over the SE Gulf will dissipate prior to
reaching the island chain. However, convection is expected to
develop over SE Florida this afternoon, and will probably be
sliding offshore from Miami-Dade County into the Atlantic waters
late this afternoon into the evening. While it is more likely than
not that this activity will remain just north of the Upper Keys,
rain chances are sufficient there to increase PoPs and include a
mention of thunder in the forecast. Following the frontal passage,
we expect moderate to fresh NW/N winds this evening to quickly
veer around to the NE late tonight, although temps and dewpoints
will drop only a few degrees.

Guidance has come into much better agreement as we head through
the middle of the week, with weak mid level disturbances remaining
over the southern Gulf and to the SW of our area, as as lower to
mid level ridge rebuilds over the northern Gulf. This pattern
should provide dry conditions for the Keys, and have removed PoPs
from the forecast from Tuesday onward. Late in the week,
strengthening high pressure over the western Atlantic will bring
increasing easterly breezes across our area. Temps will remain
near to slightly below normal, with highs in the lower to mid 80s
and lows in the lower to mid 70s. Dewpoints are forecast to hold
in the lower to mid 60s from Tuesday all the way through the
weekend, which combined with the increasing easterly flow will
provide very pleasant outdoor conditions for late April.

&&

.MARINE...
Issued at 440 AM EDT Mon Apr 22 2024

Gentle S to SW breezes of 5 to 10 knots have developed along the
reef and at Long Key C-MAN during the past couple of hours, with
seas at Satan Shoal running around 1.5 feet. Small Craft Exercise
Caution headlines have been posted for the offshore Gulf waters,
where NW winds will increase later today behind a cold front.
Small Craft Advisories may be needed for some of the eastern
marine zones tonight. From the synopsis, a cold front will move
through the Keys coastal waters today, with light to gentle
southwest to west breezes this morning becoming moderate to fresh
from the northwest this afternoon. Fresh to strong breezes will
veer from the northwest this evening to the northeast by Tuesday
morning, then moderate northeast to east breezes will prevail from
late Tuesday night through Thursday. Strengthening high pressure
over the western Atlantic will bring fresh to strong easterly
breezes to the Keys waters beginning Friday and continuing into
the weekend.

&&

.AVIATION...
(06Z TAFS)
Issued at 440 AM EDT Mon Apr 22 2024

VFR conditions will prevail at the EYW and MTH terminals through
the TAF period, with showers and storms over the Gulf waters
expected to die out prior to reaching the Keys island chain later
today. Cloud coverage will increase in the afternoon, with
possible brief MVFR ceilings beginning around 20z. Near surface
winds from the south to southwest at 5 to 10 knots will become
west to northwest after sunrise, then shift to the northwest and
increase to 10 to 15 knots as the cold front moves through the
area this afternoon.

&&

.CLIMATE...
On this day in 1940, the daily record low temperature of 62F was
recorded in Key West. Temperature records for Key West date back
to 1872.

&&

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

$$

Public/Marine/Fire...Jacobson
Aviation/Nowcasts....AP

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