National Weather Service San Juan PR
550 AM AST Fri Jan 27 2017
.SYNOPSIS...Mid level ridge located west of the region will expand
over the Northeast Caribbean and the Tropical Atlantic through Saturday.
As the ridge builds over the area...dry and stable conditions will
prevail aloft. A few upper level short-wave troughs will swing
across the local area between Sunday and early next week...
increasing the instability across the local islands. The overall
moisture transport will be enhanced the first part of next week as
a trough pattern establishes across the Western Atlantic.
&&
.DISCUSSION...Surface high pressure north of the islands will
push the remnants the old frontal boundary over the U.S. Virgin
Islands and Puerto Rico later today. As a result...scattered
showers will affect the local islands at times. Winds will become
southeast this afternoon as surface high pressure relocates over
the Central Atlantic. This will result in warmer temperatures
along Northern Puerto Rico and scattered convection over Northwest
Puerto Rico this afternoon. At this time...no significant rainfall
accumulation is anticipated with the remnants of the front as mid
level ridge will inhibit deep convection across the islands today
and Saturday.
Weather conditions will become more favorable for showers early
next week as a few short-wave troughs move over the local region.
As a result...moisture transport will be enhanced between Sunday
and Monday under the influence of the upper troughs. Operational
models continue to suggest that this wetter pattern will likely
persist through at least midweek next week.
&&
.AVIATION...Mainly VFR conditions are expected across all terminals
during the next 24 hours. However, fragmented clouds and SHRA
embedded on trade winds could create brief MVFR cigs and -RA periods
across the Leeward/USVI terminals through the morning hours. Similar
conditions are expected after 16z across the PR terminals as SHRA
develops over the mountain ranges. Low level winds should prevail
from the east at 10-15 kts with sea breeze variations after 14z.
&&
.MARINE...Local buoy observations show the overall seas subsiding
to 3-5 feet across most of the coastal waters. The NW swell peaked
yesterday, however seas up to 6 feet still possible across the offshore
Atlantic waters through tonight. Marine conditions will continue to
improve through Saturday. Winds will increase slightly again Sunday
and Monday creating seas of 4-6 feet once again across the offshore
waters.
&&
.PRELIMINARY POINT TEMPS/POPS...
SJU 84 75 86 73 / 10 10 10 10
STT 83 74 85 74 / 10 10 20 20