Scientific Forecaster Discussion
Area forecast discussion
National Weather Service San Juan PR
520 am AST Sat Dec 20 2014
Synopsis...middle to upper level ridge will continue to build over
the region through the next several days sustaining a trade wind
cap. At the surface...weak surface high pressure north of the
islands will maintain a east-northeast low level wind flow over
Discussion...mostly clear skies were observed across all local
islands tonight with isolated passing showers across the
surrounding waters. Fair weather conditions are forecast to
continue across the islands most of the weekend. However...a band
of low level moisture will reach the USVI and eastern PR late
Sunday...allowing isolated to locally scattered showers to form
near or over the U.S. Virgin Islands on Sunday afternoon. Drier
air begins to filter in again Monday through the end of next week as
upper level ridge and associated subsidence inversion strengthens
Aviation...shallow/isold rain showers but will not lower conditions blw VFR Sat-sun.
Wind east-northeast 8-18 knots surface-fl200 through sun.
Marine...local buoys are indicating seas 3-4 feet north of the
islands and below 3 feet south of the islands. For
today...nearshore winds 10-20 knots mainly from the east-northeast
and seas up to 5 feet.
Preliminary point temps/pops...
sju 84 71 83 72 / 20 20 20 20
stt 86 74 86 75 / 20 20 20 20