National Weather Service San Juan PR
455 AM AST Thu Mar 9 2017
.SYNOPSIS...Moisture advection is expected later today to result
in cloudiness and showery conditions tonight and into early Friday
morning. A seasonable weather pattern is expected to prevail Sunday
and into early next week under building mid to upper level ridge
pattern. Hazardous marine conditions as well as dangerous surf
conditions will continue to prevail today.
&&
.SHORT TERM...Thursday through Saturday...
Even though the pressure gradient is starting to relax a bit and
it is expected to continue relaxing through the day and on Friday,
the local winds are expected to continue today at around 15-20
MPH from the east to east-northeast with occasional gusts. Sea
breeze variations will be present across the southern and western
coasts of PR. Some quick showers are moving in but are not leaving
more than a few hundredths to maybe a few tenths of an inch of
rain, this is expected to continue through the very early morning
hours, improving a bit during the morning then showers are
expected to develop and affect the northern half of PR with
western PR having the higher chance of significant rain. The rest
of PR and the USVI should observe isolated brief showers today.
Having said that, overall moisture is expected to increase today
into the evening, causing showers to move in in the evening and
overnight tonight. For that reason the forecast for tonight into
early Friday morning calls for numerous showers across portions of
eastern PR and isolated to scattered showers elsewhere.
Today, max temps are expected to be slightly higher with temps
across the lower elevations forecast to reach generally between
83 and 87 degrees and in the mid to upper 70s across the higher
elevations.
&&
.LONG TERM...Sunday through Thursday...
A mid to upper level ridge is expected to build across the local
islands Sun-Mon with low level moisture eroding across the eastern
Caribbean. The ridge pattern aloft is then expected to flatten by
the end of the upcoming work week as a mid to upper level trough and
associated surface front moves across the central Atlantic. Winds
are expected to shift east southeast early next week as a surface
low develops across the western Atlantic.
Therefore under this evolving pattern, expect a seasonable weather
pattern with a few passing showers at times much of the upcoming
week. Latest guidance continues to suggest a surface front
remaining north of the area by midweek without major impact at
this time. Warmer temperatures possible Sun and early next week
under east southeast winds.
&&
.AVIATION...
VFR conds expected through the forecast period with brief VCSH
across the local terminals through 09/14Z except for TJMZ. Winds
continue from the E to ENE with sea breeze variations at around
15KT with gusts across the local terminals except TJPS and TJMZ
through 09/12Z. Thereafter, the winds should pick up to 15-20KT
with gusts to 25-30KT until around 09/22Z. Afternoon SHRA could
affect TJMZ and TJBQ as well as the vicinity of TJSJ and TJPS.
CIGS will be present after 09/14Z at around FL050.
&&
.MARINE...
Although the northerly swell will continue to slowly subside
today...fresh easterly winds will continue to create rough and
hazardous seas across the regional waters through the end of the
week. The local buoy network is indicating seas between 7 and 8
feet with breaking waves around 10 feet. As a result a High Surf
Advisory has been issued through at least 6 PM AST this evening
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.PRELIMINARY POINT TEMPS/POPS...
SJU 82 72 83 73 / 40 60 60 20
STT 83 73 83 72 / 30 40 40 20
&&