Scientific Forecaster Discussion
Area forecast discussion
National Weather Service San Juan PR
1056 am AST Sat Jul 26 2014
Update...no changes to previous...some passing showers...along with
Saharan dust and breezy conds. Temperatures currently in middle to upper
80s. Expct some afternoon convection to develop over northwest Puerto
Aviation...no changes...VFR conditions will prevail across most
taf sites through the forecast period. Afternoon rain showers/thunderstorms and rain developing
across western PR...may affect tjmz and tjbq. Surface winds will be
easterly...10 to 15 kts with gusts and sea breeze variations.
Previous discussion... /issued 432 am AST Sat Jul 26 2014/
Synopsis...TUTT pattern is expected to persist through the
weekend and into early next workweek. Surface high across
the central Atlantic will continue to promote moderate trade
winds across the forecast area.
Discussion...variably cloudy skies prevailed across the local
islands overnight...with isolated passing showers observed across
the local waters. Temperatures were in the low 80s at lower
elevations...with trade winds at 15 knots or less.
TUTT pattern aloft is expected to persist through the weekend/early
next workweek...with a closed low meandering north of the local
islands. Although it maintains a well defined circulation...system
is not deep/strong enough to put a Dent on trade winds cap across
the forecast area. In terms of precipitable water...latest GFS and
WRF guidance continues to suggest near to below normal values
through at least Thursday.
Therefore under the aforementioned pattern...continue to expect a
few passing showers across windward areas in the late evening and
early morning hours...followed by afternoon showers and an isolated
thunderstorm or two across western Puerto Rico today through at
Aviation...VFR conditions will prevail across most taf sites
through the forecast period. Afternoon rain showers/thunderstorms and rain developing across
western PR may affect areas in and around tjmz and tjbq. The rest of
the terminals may observe passing -shra/vcsh through the day. Surface
winds will be easterly at about 10 to 15 kts and gusty with sea
breeze variations from 26/13z to around 26/23z.
Marine...a moderate trade wind flow will prevail across the
local waters today. This will result in choppy marine conditions
and therefore small craft operators should exercise caution.
Seas up to 6 feet and winds 20 knots or less are expected.
Preliminary point temps/pops...
sju 89 79 90 78 / 20 20 20 10
stt 90 80 90 80 / 20 20 20 20