Area Forecast Discussion
Issued by NWS San Juan, PR

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FXCA62 TJSJ 160135 AAA
AFDSJU

Area Forecast Discussion...UPDATED
National Weather Service San Juan PR
935 PM AST Sat Jun 15 2019

.UPDATE...A few light showers are showing on radar over the local
waters. Light showers are also over northeast Puerto Rico, and
moving west. Showers are expected to re-develop later tonight.
Easterly flow will continue, but subside slowly through the night.
No changes to the grids were made so no updated zones will appear
tonight.

Saharan dust is to begin increasing late Sunday and continue
through much of the week.

&&

.AVIATION...Majority of the clouds associated with the next
tropical wave are still more than 200 miles east of TNCM/TKPK,
therefore only brief MVFR expected TNCM/TKPK tonight--if any.
-SHRA to cont ovr ern PR.

TSRA/SHRA with areas MVFR/IFR and mtn obscurations will sprd
across PR aft 16/15Z. Winds E 12 Kt or less with land breezes.
Incrg to E 10-20 kt G28kt aft 16/14Z with sea breezes alg coasts.
Max winds N 25-30 kt btwn FL390-420.

&&

.MARINE...Winds of 15 to 20 knots to continue for all but the
nearshore waters of western Puerto Rico. This will maintain seas
of 4 to 6 feet in exposed waters. Mariners will need to exercise
caution. Winds will increase during the week and small craft
advisories are anticipated, Wednesday night through at least
Friday in the southern-most waters of the outer Caribbean and
Mona Channel.

&&

.PREV DISCUSSION... /issued 541 PM AST Sat Jun 15 2019/

SYNOPSIS...A tropical wave will move across the Caribbean waters
on Sunday. A Saharan Air Layer will bring hazy skies due to
suspended Saharan dust through the work week. Another tropical
wave will move across the Caribbean waters by midweek, increasing
the chances of rain across the islands. A surface high pressure to
the north and northeast of the region will maintain a moderate to
fresh easterly wind flow for the next several days.

SHORT TERM...Today through Monday....

Afternoon showers and thunderstorms left between 1-2 inches of
rainfall across portions of the interior and western Puerto Rico
and between 0.50-1.50 inches from San Juan into Vega Baja and
Manati. By 5 pm, only isolated showers were noted over the
interior and northwestern PR. Across the USVI, sunny to partly
cloudy skies were observed as light streamers developed during
the afternoon hours. For tonight, an area of drier air ahead of a
tropical wave will move across the islands. Then between Sunday
morning into Sunday afternoon, moisture picks up once again as the
tropical wave moves across the Caribbean waters. This should
result in showers moving at times across portions of the USVI and
eastern PR during the morning hours. This will be followed by
afternoon showers and thunderstorms mainly over the interior and
western sections of PR. There is a chance for isolated
thunderstorms as well to develop over the eastern sections of PR
and across the Caribbean waters. By monday, a drier air mass with
suspended Saharan dust will filter from the east and mostly hazy
skies with limited shower activity is expected to prevail across
the region. However, diurnally induced afternoon showers can not
be ruled out over west/northwest PR.

LONG TERM...Tuesday through Saturday...From Prev Discussion

A ridge pattern aloft will result in a benign weather through the
long-term period. However, a Saharan Air Layer is forecast to
move across the islands through at least Friday, which could
create hazy skies. Another tropical wave will move over the
eastern Caribbean on Wednesday and Thursday. But, model guidance
is indicating that the bulk will remain off to the south of the
forecast area. A second tropical wave will move well south of the
islands by late Saturday or early Sunday morning. Advective
showers should not be ruled out each day across the windward
sections of the U.S. Virgin Islands and Puerto Rico. Locally
induced showers and thunderstorms will remain possible each
afternoon across western Puerto Rico.

AVIATION...VFR conds durg the prd. SCT-BKN lyrs nr FL025...
FL050...FL100 with SCT SHRA/Isold TSRA psbl over ctrl Mtn range of
PR and over coastal waters en route btw islands. Isold TSRA also
psbl ovr coastal waters of N and W Puerto Rico til 15/23Z. Sfc wnds
fm E-NE 15 to 20 kts with ocnl hir gusts and sea breeze
variations...bcmg fm E-SE less than 10 kts aft 15/23z.

MARINE...Coastal buoys across PR and the USVI were indicating
seas around 4 feet through the day and east winds between 15-20
knots. A surface high pressure across the northern Atlantic and an
approaching tropical wave currently moving over the eastern
Caribbean will maintain breezy conditions and choppy seas through
the rest of the weekend. A moderate risk of rip currents will
persist through next week across most of the northern and southern
beaches of the islands.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU  79  89  78  89 /  40  40  40  40
STT  79  89  79  89 /  40  40  40  20

&&

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

$$

SHORT TERM...WS
LONG TERM....DS


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