National Weather Service San Juan PR
1253 PM AST Fri Jan 27 2017
.SYNOPSIS...
A trough aloft is moving across the region. However, a low to mid
level ridge pattern continues to dominate the forecast area. The
surface high pressure to the north of the region is pushing a
surge of moisture associated with the remnants of the frontal
boundary across the islands. As a result, showers are expected to
develop over the surrounding waters, the U.S. Virgin Islands and
over the interior and to the north of the Cordillera Central of
Puerto Rico. As well as period of light passing rains are
expected to affect the eastern sections of Puerto Rico at times.
&&
.DISCUSSION...
The Doppler Radar detected scattered showers across the
surrounding waters. Some of this showers moved across the southern
U.S. Virgin Islands and eastern Puerto Rico, but were brief and
no significant rainfall accumulation was detected. Satellite
imagery reveals a surge of moisture with clouds and showers moving
from the east over the region. As a result, passing showers are
expected to affect mainly the Caribbean surrounding waters, the
U.S. Virgin Islands and east Puerto Rico. Also, the available
moisture is expected to combine with the local effects to induce
the development of shallow showers across the west quadrant and
the interior sections of Puerto Rico.
For the upcoming week, troughs aloft are expected to swing across
the region. In addition, a surge of moisture is forecast to
increase somewhat on Sunday. If this pattern materializes,
weather conditions will become more favorable for shower activity
during the first part of the upcoming week.
&&
.AVIATION...
Some cloudiness and SHRA embedded on east southeast trade winds
could create brief MVFR cigs and -RA periods across the
Leeward/USVI terminals through 27/22Z. Similar conditions are
expected until 22Z across the PR terminals as SHRA develops over
the mountain ranges. Mostly VFR conditions are expected across the
local flying area after 28/00Z. Low level winds should prevail
from the east southeast at around 10 kts overnight.
&&
.MARINE...
A 6 feet northerly swell was observed at the San Juan and Rincon
buoys. Therefore, mariners can expect across the Mona Passage and
Atlantic waters seas up to 6 feet. Elsewhere, seas are expected
at 3 to 5 feet. Marine conditions will improve on Saturday, but
easter fresh winds will increase the seas at up to 6 feet by
Sunday.
&&
.PRELIMINARY POINT TEMPS/POPS...
SJU 75 87 74 87 / 0 10 10 10
STT 74 84 74 84 / 10 10 20 20
&&

