Area Forecast Discussion
Issued by NWS San Juan, PR
FXCA62 TJSJ 250926
Area Forecast Discussion
National Weather Service San Juan PR
526 AM AST MON JUL 25 2016
.SYNOPSIS...Mid level ridge over the western Atlantic will shift
westward over the next few days. Deep moisture associated with a
tropical wave is forecast to reach the local region on Tuesday.
Upper level trough/TUTT will dig southwestward and relocate over
the region between Thursday and Friday. Another tropical wave
expected late in the weekend.
.DISCUSSION...Satellite loops indicated bands of moisture embedded
in the trade wind flow approaching the Northeast Caribbean Region.
This moisture advection over the local area have resulted in showers
affecting the regional waters and the windward areas. Additional
showers will move inland over portions of the U.S. Virgin Islands
and eastern Puerto Rico the rest of the morning. Stronger showers
and isolated thunderstorms are expected to develop over portions
of the West Interior and parts of the Northwest Puerto Rico this
afternoon. The U.S. Virgin Islands will experience isolated to
scattered showers at times.
Operational models indicate deep moisture associated with a tropical
wave reaching the local region on Tuesday. This will result in another
round of showers and thunderstorms across the local area. Moisture
and instability will diminish on Wednesday...reducing the shower
coverage across forecast area.
Unstable conditions will likely return to the islands at the end
of the work week as a upper trough/TUTT will move over the islands.
Then...another tropical wave is forecast to reach the local region
during the weekend. Therefore...moist and unstable pattern will
be likely the second part of the week.
.AVIATION...Mostly VFR conditions are expected to prevail with
passing -SHRA across the Leeward, USVI and E PR flying area.
SHRA/TSRA expected over western PR with areas of mtn obscurations
between 16Z-22z, resulting in brief periods of MVFR conds at
TJBQ/TJMZ. Low level winds prevail E-ESE at 10-20 knots with sea
breeze variations after 14Z.
.MARINE...Mariners can expect seas of 3-5 feet and winds around
10-20 knots over the next several days. Small craft operators should
exercise due to winds up to 20 knots across the coastal waters of
Northern Puerto Rico. Winds and seas may increase significantly
during the weekend as a stronger tropical wave moves across the
.PRELIMINARY POINT TEMPS/POPS...
SJU 89 79 89 81 / 30 50 50 30
STT 88 81 87 81 / 30 50 50 30