National Weather Service San Juan PR
353 PM AST Sat Jan 13 2018
.SYNOPSIS...Low level moisture from easterly trades has sparked
scattered showers over Puerto Rico and the U.S. Virgin Islands.
Scattered showers will continue through the rest of the day and
should start to diminish by 10 PM. Sunday the low level moisture
will begin to decrease but isolated showers are still possible
with partly cloudy conditions. A ridge of high pressure will
build in from the east and create fair weather conditions for
Puerto Rico and the U.S. Virgin Islands with a possible trade wind
shower mainly during the morning and afternoon hours.
&&
.SHORT TERM...Today through Monday... Partly cloudy skies
prevailed across Puerto Rico and the U.S. Virgin Islands today.
This morning a patch of low level moisture moved through the area
which helped triggered showers this morning and afternoon.
Doppler radar shows scattered showers across most of the northern
coast of Puerto Rico this activity will continue across Puerto
Rico and the U.S. Virgin Islands through the overnight hours. A
TUTT low will remain to the northeast of the Leeward islands until
Monday, then it will begin to dissipate. At the lower levels, a
surface high pressure system will remain over the region over the
next several days with winds out of the east to northeast 15 to 20
mph.
San Juan GFS model shows the highest precipitable water and
relative humidity values today, these values will slowly decrease
tonight through next week. An upper level ridge of high pressure
will build in from the west and hover over the region on Monday
with fair weather conditions to start the work week.
&&
..LONG TERM...Tuesday through Sunday.... Mid to upper level ridge
will remain over the region through Friday. This will cause
seasonal weather with an occasional trade wind showers across
eastern puerto rico and the U.S Virgin Islands typically during
the morning and afternoon hours. A front will move off the east
coast of the U.S. on Wednesday and will continue to progress to
the east which could help pull tropical low-level moisture across
Puerto Rico and the U.S. Virgin Islands late Thursday or early
Friday.
&&
.AVIATION...VFR conds will prevail except around TJMZ/TJBQ and in
the Leeward Islands where MVFR due to CIGS in brief passing SHRA
will occur. SHRA arnd wrn PR to end aft 13/23Z but brief MVFR to
cont in TNCM/TKPK. Mtn obscurations. Sfc winds subsiding aft 13/22Z
to bcm E 10 kt or less. East flow to resume 10 to 15 kt with gusts
to lower 20s with Sea breeze influences aft 14/14Z. Maximum winds NW
30-40 kt FL320-490.
&&
.MARINE...
&&
.PRELIMINARY POINT TEMPS/POPS...
SJU 76 84 75 85 / 30 20 10 20
STT 74 85 74 85 / 30 20 10 20