Scientific Forecaster Discussion
Area forecast discussion
National Weather Service San Juan PR
1048 PM AST Monday Mar 30 2015
Update...some light passing showers were noted over the coastal
waters with few affecting the East Coast of Puerto Rico. Rest of
tonight will remain with partly cloudy skies. Little changes were
made to forecast grids.
Aviation...mainly VFR conds next 24 hours across all taf sites.
Vcsh between 18-23z mainly in and around tjbq/tjmz. Low level east
to southeast winds will continue at 10 to 15 kts with some higher
gusts...especially in sea breeze variations after 14z.
Marine...no changes to previous discussion.
Previous discussion... /issued 315 PM AST Monday Mar 30 2015/
Discussion...by location of clouds/showers south of western PR
looks like the low level trough is focussed there while most of
the showers will be where the best heating has been (west pr).
Still...do not expect especially intense rainfall since the
moisture barely extends to 700 mb...having to break the remaining
cap but only encountering very dry air to entrain.
Drier air to arrive tonight-Tuesday night. Enough heating expected Tuesday
for at least scattered showers in northwest PR but much better
moisture to arrive Wednesday islandwide and even extending back to USVI
until late afternon. So raised probability of precipitation a little even more than the
likely we had. Grids otherwise were pretty solid and changed
Aviation...rain showers increase in central/west PR but will begin to decr again about
21z-22z. Tjmz may have periods MVFR and mountain obscure especially west and central
PR. Elsewhere isolated/scattered rain showers at most to cause isolated MVFR. Wind at or below
fl100 east 8-18 knots tonite then east-southeast Tuesday. Widespread rain showers in west and
thunder might be posbl.
Marine...winds/seas to remain relatively quiet in short term.
Models shows high pressure building in behind the decaying front
north of 30n. The resultant northeast winds will generate swell
targeting Hispaniola and Bahamas...with no 6 foot seas reaching
PR/USVI area until at least Friday.
Preliminary point temps/pops...
sju 75 87 75 88 / 10 10 30 40
stt 73 85 74 84 / 10 10 30 40