Scientific Forecaster Discussion
Area forecast discussion
National Weather Service San Juan PR
1125 am AST Monday Jul 6 2015
Update...minor changes were made to the afternoon grids...however
the inherited forecast is in good agreement with the current
observations and satellite images. Little to no shower activity
were observed inland across the local islands...meanwhile
scattered showers were detected across the local waters early this
morning. Cloudiness is increasing and showers and isolated
thunderstorms cannot be ruled out in the afternoon as the
available moisture interact with the local effects. A weak
tropical wave will pass south of the region by tonight into
Tuesday...but not significant precipitation is expected in
association with this wave.
Aviation...prevailing VFR conds expected across the local
terminals...with passing rain showers moving in and around tncm/tkpk...
tist/tisx and tjsj. Isolated thunderstorms and rain possible over west PR but no
significant impacts to the terminals are expected at this time.
Winds will be mainly from the east at 15-20kt with higher gusts.
Marine...the local buoy network was reporting seas between 3 and
5 feet and wind around 15 kts. Small craft operators should
exercise caution across the offshore waters and local passages due
to seas up to 6 feet and winds between 15 and 20 knots.
Previous discussion... /issued 506 am AST Monday Jul 6 2015/
Synopsis...patch of low level moisture will continue to move away
from the region later today. A weak tropical wave will move south
of the area Tuesday.
Discussion...a patch of low level moisture moved overnight
across Puerto Rico and the U.S. Virgin Islands. Some showers were
noted...mainly over the northern half of Puerto Rico and over the
U.S. Virgin Islands. These showers moved quickly...without any
significant rainfall accumulations.
A generally dry and stable weather pattern with some hazy
skies and limited shower activity will continue across the local
islands and coastal waters for the next few days. A weak tropical
wave will pass south of the region by Tuesday...however...significant
precipitation is not expected in association with this wave.
Another area of Saharan dust is forecast to affect region
Wednesday and Thursday...which will limit the shower activity
across the region. Latest computer guidance indicated chances of
rainfall will continue below normal for this time of the year as
high pressure continues to dominate the local region.
Aviation...prevailing VFR conds expected across the local terminals.
Passing rain showers will move in and around tncm/tkpk...tist/tisx and
tjsj through mid-morning...06/14z. Then...isolated thunderstorms and rain possible over
west PR but no significant impacts to the terminals are expected
at this time. Winds will be mainly from the east at 15-20kt.
Marine...local buoy are showing hazardous seas are diminishing
across the region. Therefore...Small Craft Advisory is expected to
expire at 11 am this morning. However...small craft operators
should exercise caution.
Fire weather...although a patch of low level moisture moved
through the area...drier air is expected to affect the region
later today into the afternoon hours. A Fire Danger Statement was
issued for elevated fire weather conditions for the South Coast
of Puerto Rico.
Preliminary point temps/pops...
sju 90 79 89 80 / 40 10 30 20
stt 90 79 89 79 / 30 20 20 20
Am...Small Craft Advisory until 11 am AST this morning for Atlantic
waters of Puerto Rico and USVI from 10nm to 19.5n-Caribbean
waters of Puerto Rico from 10 nm to 17n-Mona Passage
southward to 17n.