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fxca62 tjsj 240909 
afdsju

Area forecast discussion
National Weather Service San Juan PR
509 am AST Sat Feb 24 2018

Synopsis...at the surface, high pressure system will continue to
dominates the local region through early next week. At upper
level, a deep upper level trough (tutt) will linger west of the
area through Tuesday. This will result in favorable conditions
for the development of showers and even thunderstorms throughout
the weekend.

&&

Short term...today through Monday... numerous showers moved from
the Atlantic waters across St Thomas/St John, as well as across
the northern and eastern portions of Puerto Rico overnight. Shower
activity is expected to continue across these areas through the
morning hours. Brief periods of heavy showers are possible with
this activity. As a result some areas may observe ponding of water
along roads and poorly drained.

A mid to upper level trough with a subtropical jet over/near the
islands will support afternoon convection mainly across the interior
and southwest sections of Puerto Rico. The GFS gdi is showing the
potential for thunderstorm formation Saturday and Sunday. For that
reason, thunderstorms were added to the forecast package for
Saturday and Sunday afternoon. The islands will remain in the
divergent area of this upper level feature through at least early
next week. Therefore, expect a gradual increase in shower activity
with the possibility of isolated thunderstorms across the forecast
area.

Long term...Tuesday through Sunday...mid to upper level ridge is
forecast to build across the western Atlantic by mid next week.
Therefore, very stable atmospheric conditions are forecast to
prevail across the region during the long term period. Very dry
weather conditions with limited shower activity is anticipated.

&&

Aviation...rain showers with isolated +shra are expected to affect
tjsj/tist/tjbq through the morning hours. Vcsh are expected at the
leeward terminals too. Rain showers with possible isolated thunderstorms and rain are expected
btwn 24/16z-22z at tjmz and the vcty of tjps. East-northeast winds at 10 kt
increasing at 15-20 knots with higher gusts aft 24/13z.

&&

Marine...local buoys were indicating seas between 6-8
feet around 10 seconds period overnight and early this morning.
Seas will continue to slowly decrease through the weekend.
However, rough breaking wave action will continue to result in
life threatening rip currents along the northern exposed beaches
of PR and portions of the smaller islands through the weekend. Due
to breaking aves up to 10 feet, decided to extend the high surf
advisory until 6 PM AST tonight.



&&

Preliminary point temps/pops...
sju 81 72 81 72 / 60 60 60 70
stt 82 71 82 72 / 60 60 60 70

&&

Sju watches/warnings/advisories...
PR...high rip current risk through late tonight for Culebra-Mayaguez
and vicinity-north Central-Northeast-northwest-San Juan and
vicinity-Vieques-western interior.

High surf advisory until 6 PM AST this evening for Culebra-
Mayaguez and vicinity-north Central-Northeast-northwest-San
Juan and vicinity-western interior.

High rip current risk until 6 am AST early this morning for
central interior-southeast.

High surf advisory until 6 am AST early this morning for
southeast.

Vi...high rip current risk through late tonight for St Croix.

High surf advisory until 6 PM AST this evening for St Croix-
St... John...and adjacent islands.

High rip current risk through this afternoon for St...
John...and adjacent islands.

Small Craft Advisory from 6 PM this evening to 8 am AST Sunday
for St... John...and adjacent islands.

Am...high surf advisory until 6 PM AST this evening for coastal
waters of northern USVI and Culebra out 10 nm-coastal
waters of southern USVI Vieques and eastern Puerto Rico out
10 nm.

High rip current risk until 6 am AST early this morning for
coastal waters of southern Puerto Rico out 10 nm.

Small Craft Advisory until 8 am AST Sunday for Caribbean waters
of Puerto Rico from 10 nm to 17n-coastal waters of northern
Puerto Rico out 10 nm-coastal waters of northern USVI and
Culebra out 10 nm-coastal waters of southern USVI Vieques
and eastern Puerto Rico out 10 nm-Mona Passage southward to
17n.

High rip current risk through this afternoon for coastal waters
of northern USVI and Culebra out 10 nm-coastal waters of
southern USVI Vieques and eastern Puerto Rico out 10 nm.

Small Craft Advisory until 2 PM AST Sunday for Anegada Passage
southward to 17n-Atlantic waters of Puerto Rico and USVI
from 10 nm to 19.5n.

Small Craft Advisory until 2 am AST Sunday for coastal waters of
northwestern Puerto Rico out 10 nm.

&&

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