Scientific Forecaster Discussion

Return to Local Conditions & Forecast

Without Abbreviations
With Abbreviations

Area forecast discussion 
National Weather Service San Juan PR
100 PM AST Sat Oct 22 2016

Synopsis...ridge pattern aloft across the eastern Caribbean will
continue to hold through the weekend. Ridge pattern is expected
to weaken by early next week. At lower levels, a frontal system is
expected to moves across the western Atlantic and remain to the
north of the local islands during the weekend and early next week.


Discussion...high level cloudiness prevailed across the local
area today. Very little shower activity was observed over land
areas. A relative drier airmass has moved across the region today.
Latest tjsj 22/12z sounding showed precipitable water values of
1.71 inches. However, the limited low level moisture will combine
with daytime heating and local effects this afternoon to induce
some showers and a couple of thunderstorms over western interior
and northwest sections of Puerto Rico. This relatively dry weather
pattern is expected to persist until early next week.

Moisture is expected to pool across the local area by mid week.
Therefore, expect passing showers across the windward sections of
the U.S. Virgin Islands and Puerto Rico during the overnight and
early morning hours, followed by afternoon showers and
thunderstorms mainly across the interior and to the west of Puerto
Rico each day. Although, easterly winds are expected to return,
light winds and warm/hot temperatures are expected through the
weekend. At this time, no significant weather events are forecast
to affect the local region in the long term.


Aviation...VFR conditions are expected to prevail across the
local flying area through the rest of this afternoon and tonight.Brief
periods of MVFR conditions with mountain obscurations can be
expected across tjmz and tjbq in rain showers/isolated thunderstorms and rain through
22/22z. Low level winds will continue mainly from the southeast
at 10 kts.


Marine...seas up to 4 feet and winds up to 15 knots are expected
over the coastal waters.


Preliminary point temps/pops...
sju 78 90 79 89 / 30 30 50 50
stt 82 89 82 89 / 30 30 50 50


Sju watches/warnings/advisories...



National Weather Service Glossary of Abbreviations