871
FXUS62 KKEY 180726
AFDKEY

Area Forecast Discussion
National Weather Service Key West FL
326 AM EDT Tue Aug 18 2026

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

.KEY MESSAGES...

- A swath of Saharan dust will remain across the Keys through mid
  week.

- Warm and muggy conditions will continue throughout the work
  week, with light and often variable breezes.

&&

.DISCUSSION...
Issued at 244 AM EDT Tue Aug 18 2026
The 18/00Z KEY RAOB shows a remarkably dry air mass is in place with
PWATs sampled at just 1.12 inches, nearly a tenth below the daily
minimum of 1.21 inches for mid August. There is only one logical
culprit that is responsible for this bone dry value and the culprit
is of Saharan origin. Recent CIMMS analysis shows an extensive area
of this Saharan dust stretching from the SW Atlantic/northern
Caribbean across the Straits of FLorida and southern FL peninsula
and further westward into the southern Gulf waters. This SAL should
continue to hold its grip over the Florida Keys for another day or
two before pushing further west into the western Gulf and Mexico and
eventually Texas later in the week. As a result, rain chances will
remain suppressed with near zero chances today and Wednesday, though
a minor increase starts to occur thereafter into the end of the week
with slight PoPs returning, particularly north of the Island Chain
in the Bay/Gulf side waters. However, this will only be a very
gradual recovery of moisture with PWAT values expected to generally
still remain below daily mean values as some dry air and dust may
linger. In addition, the presence of the SAL combined with a lack
of precipitation coverage will continue to favor warm and humid
conditions with highs in the low 90s and heat indices mostly in
the 100-106 range, but some isolated higher pockets could occur
mainly in the Upper Keys, so residents and visitors are encouraged
to practice heat safety.

By the weekend, longwave troughing will gradually dig southward
across the eastern US and drop a wavy frontal boundary into the
Southeast US, which will bring enhanced moisture pooling across
the northern Gulf Coast and into northern FL. As this occurs,
shortwave energy associated with a weak wave along the
southwestern flank of Atlantic high pressure is forecast to move
near or over the Flroida Keys on Saturday, which should bring
some slightly higher rain chances for the weekend compared to
what will be observed this week. In addition, a more typical
southeasterly flow regime may attempt to become established later
in the weekend, which could bring a return of more normal rain
chances for this time of the year by late weekend and into early
next week.

&&

.MARINE...
Issued at 244 AM EDT Tue Aug 18 2026
An atlantic ridge axis draped across the coastal waters of the
Florida Keys will maintain a mostly variable wind pattern this
week with wind speeds mainly less than 10 kts. However, brief
increases in wind speeds may occur at times in the evening hours
with winds occasionally approaching 15 kts at times, so exercise
cautionary conditions could briefly occur. In addition, the
presence of saharan air across the Florida Keys will keep near
zero rain chances through the middle of the week with a very small
increase in rain chances by the end of the week as moisture
slowly recovers. The best rain chances late in the week will
typically occur north of the Island Chain in the Bay and Gulf side
waters, though any precipitation activity in general is expected
to be isolated to scattered in nature.

&&

.AVIATION...
(06Z TAFS)
Issued at 244 AM EDT Tue Aug 18 2026
VFR conditions will prevail at both Island Chain terminals
throughout the day. A light/vrb flow pattern will mostly be in
place for much of the day with winds becoming a bit more
northwesterly later in the day.

&&

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

$$

Public/Marine/Fire...RG
Aviation/Nowcasts....RG
Data Acquisition.....RG

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