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Area forecast discussion 
National Weather Service San Juan PR
241 PM AST Sat Jan 31 2015

Synopsis...middle to upper level trough entering the western
Atlantic will move over the open Atlantic waters through the
weekend. Available moisture will linger across the region for the
next few days. Surface high pressure builds to the north of the
local area early next week...tightening the local pressure


Discussion...cloudiness with showers were observed this morning
mainly over the coastal waters north of the local islands. Early
in the afternoon...showers began to develop over the Cordillera
Central of Puerto Rico. These showers were generally moving west
at 10 to 15 miles per hour. Available moisture...combined with daytime
heating and orographic effects were responsible for this shower
activity. For tonight...moisture is expected to increase a little
bit...which will enhance the chance for showers mainly along the
north coast of Puerto Rico and the northern U.S. Virgin Islands.

For the rest of the weekend through early next week...available
moisture will linger across the region. Surface high pressure
builds to the north of the local area early next week...tightening
the local pressure gradient. Therefore...winds will increase
somewhat through middle week. In the long
significant weather events are forecast to affect the local


Aviation...only brief periods of MVFR conditions are expected
across tjsj...tjmz and tjbq with vcsh possible in and around tist
and tisx until 31/22z. After 22z...mostly VFR conditions expected
across most of the local flying area. Latest tjsj sounding indicated
an east to east northeast low level wind flow up to 15 knots from
the surface to 10k feet...becoming westerly and very strong above
20k feet.


Marine...small craft advisories will be in effect late tonight
for the offshore Atlantic waters. Seas up to 7 feet and winds up to
20 knots are expected.


Preliminary point temps/pops...
sju 74 81 73 86 / 50 50 40 40
stt 73 83 75 84 / 50 50 40 40


Sju watches/warnings/advisories...
Coastal waters...Small Craft Advisory from midnight tonight to 6 am AST Wednesday
for Atlantic waters of Puerto Rico and USVI from 10nm to 19.5n.




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