Area Forecast Discussion
Issued by NWS San Juan, PR
FXCA62 TJSJ 281508
Area Forecast Discussion
National Weather Service San Juan PR
1108 AM AST SAT MAY 28 2016
.UPDATE...Current forecast package looks very much on track. The
only fly in the ointment is whether the amount of mid to high
level cloud cover will work against expected shower/thunderstorm
activity over western Puerto Rico this afternoon. Satellite images
indicate that western portions of PR may receive more sunshine
that the rest of the area allowing diaurnal heating to play a role
in this afternoon weather. Decided to keep current high chance of
precipitation to account for that possibility.
.AVIATION...Wl keep vcsh in most terminals forecast, but will
mention vcts for tjbq and tjmz in agreement with expected
afternoon activity over western/interior pr. Most tstms expected
to remain south of usvi terminals and tkpk and tncm as well.
.PREV DISCUSSION... /issued 451 AM AST SAT MAY 28 2016/
SYNOPSIS...Upper level low located over the Bahamas...will remain
near stationary through at least midweek next week. The proximity
of this feature will maintain a moist and unstable environment
across the Central and Eastern Caribbean over the next several
days. Surface high pressure northeast of the area will keep a long
fetch southeasterly flow through the end of next week.
DISCUSSION...Water Vapor Satellite loops showed an anticyclonic
circulation over the Bahamas associated with the aforementioned upper
level low. This feature aloft is sending a dense mid-upper level
clouds over Puerto Rico and the U.S. Virgin Islands. As a result...
expect mostly cloudy skies prevailing across the local region today.
Scattered showers will continue to affect portions of the local waters
and the windward areas during the morning hours. Then...deeper convection
still possible this afternoon across portions of the west interior
and northwest Puerto Rico this afternoon. The dense cloudiness will
inhibit somewhat the diurnal heating...resulting in near-normal max
temps as well as less shower and thunderstorm coverage.
Deeper moisture is forecast to pool across the islands through midweek
next week...increasing the potential for showers and thunderstorms
across the islands...especially Sunday and Monday. Upper level dynamics
will remain favorable to support the development of thunderstorms
through at least early next week as upper trough dominates the local
region. Shower activity will likely cluster over the north and
northwest sections of Puerto Rico each afternoon as southeasterly
flow will prevail most of next week.
Then...mid to upper level ridge will establish over the region
bringing more stable conditions across the islands the second part
of next week. Although...moisture will remain slightly above normal
after midweek next week...stable conditions will likely limit the
coverage of the showers.
AVIATION...Mostly VFR conditions expected thru the forecast
period across the local flying area with vicinity SHRA across
TIST...TISX...TJSJ and TJPS. SHRA and ISOLD TSRA pos after 28/18Z
across NW PR...which could affect TJBQ and TJMZ. Sfc winds from the
E to SE at around 5 to 15 knots...with higher gusts near SHRA.
MARINE...Typical marine conditions will continue across the
local waters with seas generally 3 to 5 feet and winds around
10-15 knots. No significant changes are expected over the next
.PRELIMINARY POINT TEMPS/POPS...
SJU 89 77 89 77 / 40 40 50 40
STT 88 79 86 79 / 40 40 40 40