Area Forecast Discussion
Issued by NWS San Juan, PR
FXCA62 TJSJ 291752
Area Forecast Discussion
National Weather Service San Juan PR
152 PM AST SUN MAY 29 2016
.SYNOPSIS...Upper level low located over the Bahamas and digging
into Cuba...will remain over that general area through at least
the middle of the week. There is also an area of deeper moisture
from the south that will move over the local area...the
combination of these 2 features will keep a moist and unstable
environment across the Central and Eastern Caribbean for the next
few days. Surface high pressure northeast of the local area will
keep an east southeasterly flow through the end of next week.
.DISCUSSION...Scattered to locally numerous showers affected the
local islands in the morning and early afternoon hours...mostly
over north and eastern PR in the morning and into the
afternoon...then across the northwestern quadrant of PR in the
afternoon. Some of the thunderstorms produced heavy rainfall and
frequent lightning...which caused urban and small stream flooding.
Rapid river rises were observed on those river stemming from El
Yunque Rainforest. Latest guidance and current observations
indicate that showers and thunderstorms are still expected for the
rest of this afternoon across the northwestern quadrant of
PR...while brief showers are expected elsewhere.
The upper trough is still expected to move slightly to the west
tonight...which may cause slightly less instability in the upper
levels over the local area. However...there is still plenty of
available moisture and instability to cause showers and
thunderstorms on Monday...in fact...the latest high resolution
guidance suggests that Monday afternoon will be similar to today.
For the rest of the week...the upper trough is still expected to
be over Cuba and perhaps a bit northwest of the Bahamas...this
will give way to an upper ridge slowly establishing over the
local islands. This means that we expect to have plenty of
moisture with a southeasterly wind flow but a ridge in the mid and
upper levels which should somewhat limit thunderstorm development
to only isolated thunderstorms once the moisture combines with the
local effects. Showers and thunderstorms are once again expected
on Tuesday afternoon but with slightly less coverage and intensity
according to guidance.
.AVIATION...MVFR/IFR conds possible at TJBQ due to TSRA over the
area until about 29/20Z. SHRA/TSRA may also affect TJMZ and the
vicinity of the rest of the terminals this afternoon. Sct brief
SHRA expected overnight causing brief VCSH across the local
terminals except TJMZ and TJBQ. Winds from the ESE up to 15 kt
with gusts near SHRA/TSRA...decreasing to 10kt or less overnight.
.MARINE...Seas generally 3 to 5 feet and winds up to 15 knots
overnight and into Monday.
.PRELIMINARY POINT TEMPS/POPS...
SJU 79 87 77 89 / 40 40 30 30
STT 81 86 79 85 / 40 40 40 40