Area Forecast Discussion
Issued by NWS San Juan, PR
FXCA62 TJSJ 271757
Area Forecast Discussion
National Weather Service San Juan PR
157 PM AST Mon Feb 27 2017
A ridge pattern aloft will continue through at least mid week. A
weak shortwave trough is forecast to move near the islands by
Wednesday afternoon. A strong surface high pressure to the north
of the area will produce breezy conditions through the workweek.
Patches of surface moisture will move across the islands each day.
Therefore, a trade wind pattern will dominate the local weather
through the week.
Shower activity diminished across the islands as a dry air mass
spread from the east over the region. However, the available
moisture combined with the local effects and diurnal heating will
be enough to produce scattered showers across the interior and
southwest portions of Puerto Rico. In addition, shower activity is
expected to form downwind from the U.S. Virgin Islands. Elsewhere,
expect mostly sunny to partly cloudy skies with little or no
shower activity. Satellite imagery showed another surge of
moisture near the Lesser Islands, which is expected to reach the
U.S. Virgin Islands by tonight. Therefore, once again another
round of passing showers is expected across the Windward sections
overnight and early Tuesday morning.
A strong surface high pressure over the Western Atlantic will
maintain breezy conditions most of the week. This trade wind
pattern will bring patches of moisture with showers and clouds
from time to time each day.
An upper level shortwave trough will swing by the region around
Wednesday afternoon. Although local instability will increase as a
result of this feature, the limiting factor will be the lack of
surface moisture. After midweek, once again another ridge pattern
is forecast to return.
VFR conds will prevail across the flying area. VCSH will affect
the TJMZ later afternoon. Another band of moisture will bring
scattered showers to the forecast area on Tuesday. As a result...
Brief MVFR cigs are possible after 28/10Z at TNCM/TKPK, TIST/TISX
and TJSJ at times. Low level winds of 15-25 kts will continue
Winds and seas are forecast to increase. This will produce wind
driven seas between 6 and 8 feet and easterly winds between 15 and
25 knots. Therefore, Small Craft Advisories remains in effect
from this evening through most of the week. Refer to the local
marine products for additional information.
.PRELIMINARY POINT TEMPS/POPS...
SJU 76 85 76 85 / 30 40 20 20
STT 75 85 75 85 / 30 40 20 20
PR...VI...Small Craft Advisory from 8 AM Tuesday to 2 AM AST Friday for
St.Thomas...St. John.. and Adjacent Islands.
AM...Small Craft Advisory from 8 PM this evening to 8 PM AST Friday
for Anegada Passage Southward to 17N-Atlantic Waters of
Puerto Rico and USVI from 10 NM to 19.5N-Caribbean Waters
of Puerto Rico from 10 NM to 17N-Mona Passage Southward to
Small Craft Advisory from 8 PM this evening to 2 AM AST Friday
for Coastal Waters of Southern USVI Vieques and Eastern
Puerto Rico out 10 NM.
Small Craft Advisory from 8 AM Tuesday to 2 PM AST Thursday for
Coastal Waters of Northern Puerto Rico out 10 NM.
Small Craft Advisory from 8 PM this evening to 2 AM AST Thursday
for Coastal Waters of Northern USVI and Culebra out 10 NM.