National Weather Service San Juan PR
521 AM AST Tue Jan 29 2019
.SYNOPSIS...A strong mid level ridge over the region will promote
drier air and fair weather conditions through the end of the
week. A weak surface high pressure over the central Atlantic will
maintain a light to moderate easterly wind flow for the next
several days. Showers will be limited to light trade wind showers
across the USVI and eastern sections of PR during the night and
early morning hours, followed by diurnally induced shallow
convection over western PR each afternoon.
&&
.SHORT TERM...Today through Thursday...
A surface high pressure will continue to promote an easterly wind
flow which will bring patches of low level moisture with clouds and
showers at time. At upper levels, a strong mid-level high pressure
will induce subsidence promoting dry air over the islands. Under
this weather pattern, fair weather conditions with mostly sunny
skies will continue through the short term. Shower activity, if any,
will be brief and shallow resulting in minor rainfall accumulations.
Maximum temperatures will continue around the mid 80s across the
coastal areas and in the upper 70s along mountains and valleys. On
the other hand, minimum temperatures will range from the high 50s
along the mountain areas to mid 70s elsewhere.
.LONG TERM...Friday through Wednesday...
An upper level ridge will maintain dry air aloft and stable
conditions through the weekend. However, an upper level trough
will press against the ridge late in the period and the ridge is
expected to collapse by Sunday. At lower levels, a weak surface
low is forecast to move from the southwestern Atlantic on Saturday
and move slowly into the central Atlantic by early next week. A
shearline is expected then to increase moisture and instability
over the region. A surface high pressure is forecast to build
behind the low and across the western Atlantic by Tuesday. This
will promote a moist northeast wind flow over the region through
the middle of the week.
&&
.AVIATION...VFR conditions will continue across the flying area.
Calm to light and variable winds will persist through 29/13z,
returning from the east around 15 knots with sea breeze variations
after that.
&&
.MARINE...Seas will range between 3-5 feet across the regional
waters through the end of the week. However, a northerly swell
will increase seas up to 6 feet on Thursday across the Atlantic
waters. Light to moderate trades will prevail for the next several
days. There is a moderate risk of rip currents for the northern
and southern beaches of PR and St. Croix.
&&
.FIRE WEATHER...Elevated fire weather conditions along the southern
coastal plains of Puerto Rico today. Please refer to the latest
fire weather forecast (FWFSJU) and fire danger statement (RFDSJU) for
more information.
&&
.PRELIMINARY POINT TEMPS/POPS...
SJU 84 72 85 74 / 30 30 10 30
STT 83 72 83 72 / 40 40 20 10