FFASJU) is in effect
for all of Puerto Rico and the U.S. Virgin Islands through at
least Thursday morning. Flash flooding caused by excessive
rainfall continues to be possible where there is the increased
risk for urban and flash flooding, rapid river rises and
mudslides. As low- level wind speed convergence continues over the
region, we can expect fresh to locally strong wind speeds at
times, with stronger gust.

Model guidance continues to suggest this evening into tomorrow as
the heaviest window of activity for Puerto Rico, with a focus of
showers over the U.S. Virgin Islands during the morning hours by
tomorrow afternoon. This is associated with the positioning of the
upper-level trough over the eastern Caribbean and the abundance
of moisture. Winds will begin to veer throughout the day, becoming
westerly by the evening hours. This will further concentrate
heavy rainfall across eastern Puerto Rico and the USVI.

By Thursday, a strong surface high pressure over Southeastern
USA, and the surface low now over the north central Atlantic will
promote northerly winds across the western Atlantic into the
northeastern Caribbean. This will cause the local winds to continue
to veer, becoming north-northwest by the evening hours which is
expected to push the tropical plume of moisture further east and
away from the local area. However, the position of the upper-
level trough axis, cool 500 mb temperatures, and lingering
moisture will promote a continued weather pattern of showers and
thunderstorms through late Thursday.

&&

.LONG TERM...Friday through Tuesday...
/from previous discussion/
A drier and more stable trend is forecasted for the beginning of
the long term. Model guidance indicates a more stable pattern at
the upper levels as the divergent side of the polar trough moves
eastward out of the forecast area, leaving subsidence over the
islands and being replaced by ridging. A similar trend is expected
at the mid- levels, with the GFS suggesting a broad building mid-
level ridge extending from the western Atlantic into the
Caribbean. The presence of the mid-level ridge will begin on
Friday afternoon and persist for the rest of the period as it
stretches into the central Atlantic.

The last part of the long-term global model guidance shows some
discrepancies between the two solutions, one stable and drier and
another stable but with more moisture. According to the GFS, from
Friday onwards and for the rest of the forecast period, the
islands are expected to be mostly dominated by a building surface
high-pressure system extending from the western Atlantic into the
Central Atlantic, resulting in northerly winds for Friday and
veering winds for the rest of the forecast period. Conversely, the
ECMWF solution shows a similar trend with a surface high-pressure
system located over the western Atlantic, but from Sunday into
Monday, the guide suggests a decent increase in humidity at 850 MB
and a weak short-wave trough over the area. As we are still far
away in the forecast, the forecast for the last part of the long
term reflects a combination of both solutions, resulting in a
variable weather pattern, given the presence of the mid-level
ridge causing a strong trade wind cap inversion and drier air
aloft.

&&

.AVIATION...
(18Z TAFS)

Squally weather will persist throughout the forecast period. A
TSRA/+TSRA will create occasional MVFR, IFR, or brief LIFR conds
across local terminals. The unsettled weather conditions will
continue, associated with a frontal boundary and a deep-tropospheric
trough. Winds will persist at low levels between 15 and 25 knots
with higher gusts that may fluctuate between 25 and 35 knots or be
even more significant in/near TSRA/+TSRA.

&&

.MARINE...

A broad surface low pressure will continue to build over the western
Atlantic and move into the north central Atlantic by Thursday. The
interaction of this low with the broad Atlantic ridge extending into
the eastern Caribbean, will result in fresh to locally strong winds,
hazardous seas and squally weather across the regional waters and
passages through at least early Thursday morning. South to
southwesterly winds will prevail through Wednesday, becoming
northerly Thursday onwards as a broad surface high pressure builds
over the western Atlantic during the second part of the week. Pulses
of a northerly swell will spread across the local waters from later
today through the weekend.

For beachgoers, starting tomorrow there will be a high rip
current risk across all the northern, western, and eastern
coastal areas of Puerto Rico including Culebra and a moderate risk
elsewhere. An increase in breaking waves is forecast tomorrow
into the rest of the workweek, strengthening even more over the
weekend.

&&

.SJU WATCHES/WARNINGS/ADVISORIES...
PR...Flood Watch through late Wednesday night for PRZ001>013.

     High Rip Current Risk from Wednesday morning through Tuesday
     afternoon for PRZ001-002-005-008-010-012.

VI...Flood Watch through late Wednesday night for VIZ001-002.

AM...Small Craft Advisory until 8 AM AST Monday for AMZ711.

     Small Craft Advisory from 2 PM Wednesday to 8 AM AST Monday for
     AMZ712-742.

     Small Craft Advisory until 3 AM AST Wednesday for AMZ716.

     Small Craft Advisory until 2 PM AST Wednesday for AMZ723.

     Small Craft Advisory until 8 PM AST this evening for AMZ726.

     Small Craft Advisory from 8 PM this evening to 8 AM AST Monday
     for AMZ741.

&&

$$