Area Forecast Discussion
Issued by NWS San Juan, PR
FXCA62 TJSJ 231849
Area Forecast Discussion
National Weather Service San Juan PR
249 PM AST TUE AUG 23 2016
.SYNOPSIS...A strong tropical wave located about 400 miles east
of the U.S. Virgin Islands will continue to move west-northwest at
around 15-20 MPH. As a result...Showers and thunderstorms associated
with this strong wave will affect the local islands on Wednesday.
Residual moisture associated with the trailing edge of the tropical
wave will likely bring another round of showers and thunderstorms
Thursday afternoon. Moisture will gradually diminish on Friday,
with drier than normal conditions expected during the weekend.
.DISCUSSION...Satellite imagery indicate that the strong tropical
several hundred miles east of the forecast area has elongated
since this morning. This result in a broad area of showers and
thunderstorms near the wave axis. The tropical wave is forecast to
reach the local area early Wednesday morning. Shower and
thunderstorm activity will be more frequent as the day progresses.
As a result... the potential of flash flooding remains high across
most of the islands...therefore a Flash Flood Watch is in effect
for all Puerto Rico and the U.S. Virgin Islands between early
Wednesday morning and late Wednesday night. Although...most of the
local islands will receive heavy rains...the highest rainfall
accumulations will likely occur over the U.S. Virgin Islands and
the eastern half of Puerto Rico. Additional impacts associated
with this strong tropical wave are strong gusty winds up to 30-40
MPH with the heaviest showers and thunderstorms, hazardous marine
conditions and high risk of rip currents.
Trailing moisture associated with the tropical wave will bring another
round of showers and thunderstorms on Thursday afternoon. Moisture
will gradually diminish on Friday. Then...fair weather conditions
expected during the weekend.
.AVIATION...Few passing -SHRA/SHRA ovr coastal waters an en route
btw PR and Nrn Leeward islands. SCT ocnl BKN cld lyrs FL025...
FL050...w/brief VCSH til 23/14z across the USVI terminals, TJSJ, and
also TNCM and TKPK. Otherwise VFR conds expected through 23/15Z.
Diurnally induced SCT SHRA/ Isold TSRA psbl across central and
western PR after 23/17Z with psbl VCSH/VCTS mainly at TJMZ and N of
TJPS til 23/22Z.
.MARINE...Marine conditions will deteriorate overnight as a
strong tropical wave moves across the northeast Caribbean. Seas
will increase 5 to 7 feet with occasionally seas 8 to 9 feet.
Lightning and Gusty winds up to 30 knots will be the main hazard
for mariners...especially across the offshore Atlc waters.
.PRELIMINARY POINT TEMPS/POPS...
SJU 79 86 78 89 / 80 80 70 70
STT 79 86 78 87 / 80 80 70 70
PR...Flash Flood Watch from late tonight through Wednesday evening
for Central Interior-Culebra-Eastern Interior-Mayaguez and
Vicinity-North Central-Northeast-Northwest-Ponce and
Vicinity-San Juan and Vicinity-Southeast-Southwest-Vieques-
VI...Flash Flood Watch from late tonight through Wednesday evening
for St Croix-St.Thomas...St. John.. and Adjacent Islands.
AM...Flash Flood Watch from late tonight through Wednesday evening
for Coastal Waters OF Southwestern Puerto Rico out 10 NM-
Coastal Waters of Northern USVI and Culebra out 10 NM-
Coastal Waters of Southern Puerto Rico out 10 NM-Coastal
Waters of Southern USVI Vieques and Eastern Puerto Rico out
Small Craft Advisory from 8 AM Wednesday to 8 AM AST Thursday
for Atlantic Waters of Puerto Rico and USVI from 10 NM to