Info HWO Hazardous Weather Outlook — Tue Aug 24, 2021 1:30 PM

HWOSJU)
issued by the National Weather Service San Juan forecast office
for details.

SHORT TERM...Today through Thursday...

Relatively fair weather conditions are anticipated through the short
term period. Hazy skies due to Saharan dust particles will continue
to linger over the area during the morning hours. Satellite imagery
and aerosols dispersion models show less saharan dust cloud coverage
over the forecast area by this afternoon. Thus, visibilities are
expected to improve under mostly sunny to partly cloudy skies for the
rest of the short term period. At the upper levels, the TUTT low
will move away from the area today into tomorrow, bringing less
favorable conditions aloft for shower enhancement. The strong
inversion cap at mid levels is the most predominant feature in the
forecast. This feature, together with below normal PWAT values
will result in limited shower activity, if any, across the
forecast area. Warm daytime and night time temperatures will
persist during the next days and heat indices above 100 degrees
are also expected mainly for parts of the coastal and urban
sectors of the islands. Winds will be generally from the east
between 15 to 20 knots with higher gust and sea breeze variations.

LONG TERM...Friday through Tuesday...

No significant changes in the long-term forecast period with
today`s update, with the most recent model guidance suggesting a
generally stable and dry weather pattern dominating the forecast
area. A slight increase in moisture can be expected by Friday due
to the passage of a weak tropical wave, with PWAT briefly
reaching above-normal values around 1.70 inches by Friday
afternoon. This increase, along with somewhat favorable conditions
aloft generated by a westward-moving Upper Level Tropospheric
Trough (TUTT) may generate favorable conditions to support
enhanced convective development across the region; following the
seasonal diurnal shower pattern.

By Saturday and continuing through the rest of forecast period,
model guidance do not suggest any other rainfall enhancer, with
mid to upper level ridging becoming the dominant feature. That
said, mainly fair weather conditions are expected, with below
normal PWAT values of 1.50 inches or below supporting limited
shower activity. Saharan dust particulate will also be present,
gradually filtering the area in the wake of the aforementioned
tropical wave and reaching a concentration maxima by Sunday into
Monday. Thus, expect hazy conditions and reduced visibilities.
Daytime highs are forecast to peak into the lower 90s across lower
elevations and urban areas, with heat index that could reach the
lower to mid 100s each day.

AVIATION...Mainly VFR conditions are expected across all terminals
through the 24 hour forecast period.  HZ due to Saharan dust is
expected through the afternoon, but no impact to VIS is anticipated.
Winds will be up to 15KT gusting to 20-25KT from the E with sea
breeze variations. Winds will decrease after 24/23Z.

MARINE...Small craft operators should continue to exercise
caution due to choppy seas up to 6 feet and/or winds up to 20
feet expected across the Caribbean waters and both Anegada and
Mona Passages. Elsewhere across the regional waters, tranquil
marine conditions with seas up to 5 feet and winds up to 15 mph
will continue. A moderate risk of rip currents continues for most
beaches except for some of the protected beaches along the south
and west coast of Puerto Rico and the northern US Virgin Islands.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU  89  81  90  79 /  20  10  10  10
STT  90  81  90  81 /  10  10  10  10

&&

.SJU WATCHES/WARNINGS/ADVISORIES...
PR...None.
VI...None.
AM...None.
&&

$$