Area Forecast Discussion
Issued by NWS San Juan, PR
FXCA62 TJSJ 200845
Area Forecast Discussion
National Weather Service San Juan PR
445 AM AST Fri Jan 20 2017
Mid to upper level trough will shift further east of the region
today through Saturday as an upper level high pressure ridge is
expected to build over the western Atlantic then spread across
the region by Sunday and Monday. In the meantime weak a mid level
perturbation is to move just north of the region today and Saturday.
Surface high pressure over the western Atlantic and an area of
Low pressure across the north central Atlantic will create a very
light north to northeast trade wind flow across the region today
through Saturday. The remnants of a cold front is forecast to slowly
sink southwards across the local Atlantic waters Saturday through
Sunday. A high pressure ridge will then spread across the west and
southwest Atlantic. Local winds are to then become more southerly
by Sunday and Monday as this high pressure ridge will sink farther
south across the northeastern caribbean.
.DISCUSSION...Mostly clear skies and little or no shower activity
was observed of reported over land area. light to moderate showers
were noted across the offshore waters and just northwest of PR.
these showers were slowly rifting southwards across the coastal
waters. Winds were light and variable to calm in most areas. Early
morning low temperatures were in mid 60s to near 70 degrees along
coastal areas and between 55-60 degrees in higher elevations and
Mostly fair skies and pleasant seasonal weather conditions can be
expected today across most of the region. A few light showers may
form across parts of the islands but activity if any will be of
For the weekend and into early next week, patches of low level
moisture along a weakening cold front/frontal boundary move across
the region and aid in the development of some showers across the
northern half and parts of the interior sections of Puerto rico
especially during the early morning and afternoon hours. Lesser
shower activity is expected across the remainder of the islands.
No significant rainfall or accumulations is expected through the
weekend. The low level easterly winds are to become more southerly
by late Sunday and into early next week resulting in slightly
warmer temperatures to the region.
.AVIATION...VFR conditions will continue across the local terminals
during the next 24 hours as fair weather is expected to prevail.
Calm to Light and VRB winds expected through 20/13Z...becoming light
and northerly thereafter with sea breeze variations. No significant
weather hazard expected.
.MARINE...Marine conds will continue to improve today and into the
upcoming weekend as Seas will slowly subside to between 1-4 feet
nearshore and 3-5 feet offshore and local passages. A gentle
north to northeast wind flow will prevail today, becoming more
southerly by late Sunday and continuing into early next week.
There are hazardous impacts for the coastal waters today.
.PRELIMINARY POINT TEMPS/POPS...
SJU 81 72 82 71 / 0 30 30 40
STT 80 70 82 70 / 0 30 30 40