Puerto Rico Weather

Area Forecast Discussion
National Weather Service San Juan PR
500 AM AST FRI JUN 24 2016

.SYNOPSIS...TUTT will amplify into the eastern Caribbean today.
At lower levels, a high pressure across the north central
Atlantic will continue to promote an easterly wind flow during
the next several days. Tropical wave will remain well south of
the area today and into Saturday.

&&

.DISCUSSION...Partly to variably cloudy skies were observed
during the overnight and early morning hours across the local
islands. Doppler weather radar indicated trade wind showers
affecting USVI and the eastern sections of Puerto Rico as well
as the surrounding coastal waters. Temperatures across coastal
areas were in the mid to upper 70s and the wind was easterly
at 10 mph or less.

Although TUTT across the central Atlantic will amplify into
the eastern Caribbean today and hold through early next week,
precipitable water will remain near normal values through Monday.
Tropical wave will move across the eastern Caribbean and well
south of the local islands today and into Saturday. In addition,
SAL is expected to reach the eastern Caribbean later today and
continue to prevail during the upcoming weekend. This pattern
will result in seasonable weather conditions today through Monday
with locally induced showers and thunderstorms across west Puerto
Rico in the afternoon hours each day.

Precipitable water values will increase Tuesday and Wednesday,
however the best moisture advection is expected on Friday as a
tropical wave with plenty of moisture moves across the eastern
Caribbean.

&&

.AVIATION...Brief trade wind -shra will continue to affect the
local flying area through 24/12Z producing brief VCSH. VFR
conditions expected across the local terminals through 24/16Z.
After 16Z, SHRA/TSRA may develop in the vicinity of TJMZ and TJBQ
which may affect the terminals and cause brief MVFR conditions.
Low level winds will be light and easterly through 24/13Z,
thereafter from the E-ESE at around 10-15KT with sea breeze
variations and occasional gusts.

&&

.MARINE...Tranquil marine conditions are expected during the next
few days with seas up to 5 feet and winds 15 knots or less.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 89 77 87 77 / 20 10 20 20
STT 89 80 88 79 / 20 20 20 20

Area Forecast Discussion
National Weather Service San Juan PR
534 AM AST SUN JUN 26 2016

.SYNOPSIS...TUTT across the central Atlantic and into the eastern
Caribbean will shift east through the day, while weakening. Another
TUTT will then develop across the western Atlantic and into the
northern Caribbean isles by Tuesday. Weak mid level ridge will
hold much of the next workweek. A surface high across the north
central Atlantic will continue to prevail during the next several
days. The next tropical wave passage is expected on Friday.

&&

.DISCUSSION...Partly cloudy skies were observed during the overnight
and early morning hours with a few isolated showers detected
across the north and east coastal areas of Puerto Rico as well as
the USVI. Coastal temperatures were in the low 80s and the wind
was easterly at 10 mph or less.

As TUTT shifts to our east while weakening, its convergent side
will begin to dominate the area. However, this pattern is short-
lived as another TUTT develops across the western Atlantic and
into the northern Caribbean islands with favorable upper level
dynamics expected across the area Tuesday and early Wednesday.
Precipitable water will continue near normal values through Monday
with a sharp increase Tuesday/early Wednesday. Therefore, under
this evolving pattern continue to expect afternoon showers and
thunderstorms across west Puerto Rico today and Monday. Intensity
and coverage of showers and thunderstorms, including across the
USVI, should increase Tuesday and early Wednesday as moisture
increases and trofiness dominates the forecast area. Late
Wednesday through early Friday, a fair weather pattern is expected
to prevail under limited low level moisture. The chance for
showers and thunderstorms will increase once again Friday
afternoon with the passage of the next tropical wave.

&&

.AVIATION...VFR conditions expected over most terminals through
26/17Z. SHRA and ISOLD TSRA expected to develop over west and
interior Puerto Rico between 26/17Z and 26/22Z so at least VCTS is
expected for TJBQ, TJMZ, and TJPS. However, these is also a chance
of SHRA and ISOLD TSRA in the vicinity of TJSJ, but not as
persistent. Sfc winds should prevail from the E at 10-15KT with
occasional gusts and sea breeze variations.

&&

.MARINE...Tranquil marine conditions are expected during the next
few days, with seas 5 feet or less, and winds at 10 to 15 knots.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 89 79 90 78 / 20 20 20 20
STT 91 80 91 79 / 20 30 30 30

Area Forecast Discussion
National Weather Service San Juan PR
435 AM AST TUE JUN 28 2016

.SYNOPSIS...Surface high pressure over the North Central Atlantic
will continue to promote East to E-SE trade winds for the next
several days. Upper trough to the northwest of Hispaniola will
continue to dig and develop a low which is expected to be cutoff
and over Hispaniola by Thursday. Increase in moisture is expected
to today over the local islands causing locally induced showers
and thunderstorms across portions of Puerto Rico in the afternoon
hours.

&&

.DISCUSSION...Brief trade wind showers have persisted over the
local waters through the overnight hours, mainly over the local
waters, but some briefly reaching the USVI and eastern PR. These
brief showers are expected to continue through the morning hours.
Even though the upper low that has affected us the past few days
has now weakened and moved away, the increasing moisture will
combine with the local effects and diurnal heating to cause the
development of showers and thunderstorms mainly across the
northwestern quadrant of PR. Other areas in PR are expected to
observe showers and thunderstorms such as portions of the San Juan
metro area and portions of eastern PR but these areas are not
expected to receive the persistent moderate to heavy showers that
are expected in the central into northwestern PR. Isolated
showers are expected elsewhere, but clouds and rain streaming off
the USVI, Vieques and Culebra are expected.

This pattern of locally induced showers is expected once again on
Wednesday, then things dry off a little late Wednesday into
Thursday before moisture increases significantly on Friday as a
tropical wave approaches. The moisture associated with the
tropical wave is expected to remain over the local area through
Saturday, with slightly drier air moving in by Sunday morning.
According to long range models, another tropical wave may approach
the local area early next Tuesday.

&&

.AVIATION...VFR conds expected to prevail at all TAF sites during
the forecast cycle. However...SHRA/TSRA expected to develop across
west Puerto Rico between 28/16Z and 28/22Z...with MVFR conds
possible in and around JBQ/JMZ. There is also a chance for SHRA/
ISOLD TSRA in the vicinity of JSJ. Winds from the SE at 10-15KT
with occasional gusts and sea breeze variations.

&&

.MARINE...Tranquil marine conditions expected today across the
local waters. There is a moderate risk of rip currents across the
beaches of northern Puerto Rico and the beaches of North and East
Saint Croix.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 89 78 90 79 / 20 20 20 10
STT 89 80 89 79 / 20 30 30 20

Area Forecast Discussion
National Weather Service San Juan PR
523 AM AST THU JUN 30 2016

.SYNOPSIS...Tropical waves will move throught the area on Saturday
and Monday night through Tuesday to increase the chances of
showers and thunderstorms. Heavier dust will be behind each wave.
Otherwise there will be limited convection and precipitation
across the local area.

At upper levels...An upper level cut-off low north of Hispaniola
will move across Cuba on Saturday night. A second low will form
northeast of the Leeward Islands on Saturday night and move slowly
westward. It is expected to be north of Puerto Rico by next
Thursday.

At mid levels...High pressure will develop north of the forecast
area and continue through Monday. A tropical wave will be evident
in its transit of the area on Tuesday. It will form a weak low
north of Hispaniola late next week.

At lower levels...Moderate high pressure in the north central
Atlantic will drift east over the Azore Islands saturday night. A
ridge of high pressure will continue to cross the Atlantic to the
northern Bahama Islands through the end of next week. This will
keep moderate to fresh east to east southeast trade winds across
the forecast area through the period.

&&

.DISCUSSION...A few tiny showers formed lines as they moved across
the Caribbean toward the west. Very few showers moved over Puerto
Rico. A few showers were seen crossing Saint John and Saint
Thomas. The tropical wave that crossed mainly south of the area
Wednesday night and Thursday is now south of the Dominican
Republic. Drier air was seen on the MIMIC product entering the
area from the east, but moisture will gradually increase through
Saturday bringing an increase in shower and thunderstorm activity
ahead of another tropical wave that will cross Puerto Rico
Saturday evening. Conditions are expected to dry until the next
wave moves through Monday night and Tuesday. This is expected to
be the wettest wave of the next 10 days. Even so, moisture at mid
levels is brief and limited.

Showers are expected each afternoon in western Puerto Rico, but
during the drier breaks other areas of the island will have few
showers. Isolated thunderstorms are possible from the heavier
showers, but most will not be able to penetrate the drier mid
levels.

&&

.AVIATION...VFR conds are expected to prevail at all TAF sites
during the forecast period. Fair weather is expected through 16Z
with only brief ISOLD -SHRA over the local area. SHRA and ISOLD
TSRA are possible across NW PR after 16Z, causing VCSH/VCTS at
TJMZ and TJBQ. VCSH is also possible at TJSJ between 16Z-22Z. Low
level winds from the E- ESE at 10-20 kts with sea breeze
variations after 13z.

&&

.MARINE...Winds and seas will increase around and behind the
tropical waves expected Saturday night and Tuesday. There is a
good chance that small craft advisories will be need for seas of 7
to 8 feet in the northern part of our local Atlantic waters.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 91 80 89 80 / 10 20 30 40
STT 90 80 89 79 / 20 20 30 40

Area Forecast Discussion
National Weather Service San Juan PR
526 AM AST SAT JUL 2 2016

.SYNOPSIS...Tropical wave will exit the local area Today. Saharan
dust and drier conditions expected Sun-Mon. Next tropical wave
enters the eastern Caribbean on Tuesday. Upper ridge builds just
north and over the area thru Monday. By Tuesday, TUTT low is
forecast to develop and meander just to the northeast of the
forecast area through much of next week. Broad surface high
pressure will continue across the eastern Atlantic, generating
moderate to fresh trade winds.

&&

.DISCUSSION...Tropical wave generated scattered showers and
isolated thunderstorms across the waters and coastal areas of the
U.S. Virgin Islands and eastern PR during the overnight hours.
Rainfall ranged between 0.25-0.50 inches of rain with the heaviest
showers. For Today, scattered to numerous showers and
thunderstorms are expected mainly across the interior and western
sections of PR. Tropical wave will exit the local area tonight.
Saharan dust is trailing the wave and drier conditions with
limited afternoon shower development is expected thru at least
Monday. On Tuesday, a strong tropical wave is forecast to enter
the eastern Caribbean but is expected to move mainly south of the
islands. However, TUTT low developing just northeast of the area
could interact with the wave and enhance showers and
thunderstorms across the islands.

&&

.AVIATION...Tropical wave will move across the flying area
today...resulting in SHRA and TSRA. SHRA activity expected across
eastern PR as well as the USVI and local waters in the morning.
Then...SHRA/TSRA expected across the interior and western sections
of PR after 02/16Z...with periods of MVFR conds for TJBQ/TJMZ are
possible at times. East winds at 10-20 kt with higher gusts near
SHRA/TSRA.


&&

.MARINE...Hazardous marine conditions with choppy seas up to 7
feet are expected across portions of the offshore Atlantic waters
and Anegada Passage. Elsewhere, small craft operators should
continue to exercise caution due to seas up to 6 feet and east
winds up to 20 knots. As tropical wave continues to move west
just south of the islands isolated thunderstorms are expected.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 88 79 90 79 / 40 10 0 30
STT 89 81 89 80 / 50 10 10 30

Area Forecast Discussion
National Weather Service San Juan PR
544 AM AST MON JUL 4 2016

.SYNOPSIS...Ridge aloft will continue to gradually erode over the
next few days, as a tutt low located just northeast of the northern
Leeward islands, shifts westward and relocates north of the forecast
area by Wednesday. This feature is to then hold north of the area through
the remainder of the week. Surface high pressure will continue to prevail
and remain the dominant feature across the north central Atlantic during
the next several days. A tropical wave with axis just east of the Lesser
Antilles is forecast to enter the eastern caribbean later this evening,
then move across the forecast area Tuesday through early
Wednesday.

&&

.DISCUSSION...Mostly clear to partly cloudy skies prevailed across
the islands during the overnight hours. A few clouds and quick
passing showers moved across the regional waters and briefly
affected parts of the north and east coastal sections of some of
the islands. However so far no significant rainfall accumulations
were observed or reported. Early morning low temperatures across
coastal areas were high 70s to low 80s, and the wind over land
was mainly from the east at 5-10 mph.

For the rest of the day,mostly sunny skies and fair weather conditions
is forecast for most areas, under the present high pressure ridge pattern
and limited low level moisture advection. Except for local sea breeze
variations winds will be generally from the east at 15-20 mph with
occasionally higher gusts along the coastal areas. The local weather
pattern is however expected to change later tonight through early Tuesday
as the tropical wave enters and moves across the eastern caribbean.


The axis of the previously mentioned tropical wave was now located
near 54W, and is forecast to cross the Lesser Antilles later tonight.
This approaching feature along with the proximity of the upper level
trough moving north of the region will bring an increase in tropical
moisture and instability to the region. As a result deteriorating
weather conditions and isolated areas of squally weather conditions
will be possible across parts of the coastal waters, the U.S Virgin
Islands and eastern Puerto Rico by early Tuesday. These conditions
will later spread to the west portions of Puerto Rico during the
rest of the day on Tuesday. So far latest model guidance and recent
satellite imagery all suggest Tuesday as the most active weather
day. Widespread rainfall accumulations are not anticipated at this
time, however urban and small stream flooding will be possible in
isolated areas across the islands.

Weather conditions are then expected to improve by Wednesday, but locally
induced showers and isolated thunderstorms can still be expected mainly
across parts of the interior and west sections of Puerto Rico due to
the lingering moisture trailing the wave. A much drier air mass is then
expected by Thursday and through the upcoming weekend.

&&

.AVIATION...VFR conds are expected to continue at all TAF sites
through the forecast period. VCSH expected for TJSJ, TIST,TISX with
some directly affecting the terminals on occasion. SHRA/VCTS
activity expected after 04/17Z at TJMZ and pos TJBQ, causing brief
MVFR conds. Winds from the east at around 15-20kt with higher gusts
after 04/13Z.

&&

.MARINE...Winds and seas will increase during the next 48 hours as
a tropical wave moves across the regional waters. As a result small
craft advisories can be expected for some of the coastal waters from
now through Tuesday. Elsewhere small craft should continue to exercise
caution. Please refer to the latest Coastal Waters forecast and Marine
Weather Message issued by WFO San Juan PR, for additional information.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 89 78 88 79 / 20 50 50 20
STT 91 79 87 80 / 20 50 50 30

Area Forecast Discussion
National Weather Service San Juan PR
557 AM AST WED JUL 6 2016

.SYNOPSIS...
A tutt low now locate north of the islands will continue to move
northwest of the region through late Wednesday. Thereafter, high
pressure aloft will then move across the area from the east and
northeast beginning on Thursday, relaxing the pressure gradients
and somewhat reducing surface wind velocities through Saturday.
Recent aerosol models indicate Saharan Air Layer moving into the
area from the east and persisting through Friday. Surface high
pressure across the Northeast Central Atlantic will continue
through the next several days.

&&

.DISCUSSION...
Fair weather conditions with mostly clear to partly cloudy skies
prevailed across the local islands and coastal waters during the
night and early morning hours. A few light showers were observed
moving quickly northwestward across the nearshore Atlantic
waters. At the moment, little to no shower activity has been
detected inland.The winds were mainly from the east at 5-10 mph
and the minimum temperatures were in the upper 70s to lower 80s
across the coastal areas.

As the tutt low continues to move northwest of the area, a drier
air mass will move in from the east along with suspended Saharan
dust. Thus, mostly fair weather conditions are expected to prevail
today. However, some lingering moisture combined with the local
effects and diurnal heating may still aid in some convective
development during the afternoon hours. A chance of showers and
isolated thunderstorms is possible mainly across the interior and
western portions of Puerto Rico. Hazy conditions and maximum
temperatures between the upper 80s and lower 90s is also expected
for today.

Area of high pressure across the mid and upper levels is expected
to prevail through at least Friday. As a result, a similar weather
pattern with limited shower activity can be expected to continue
through the end of the work week. Also, pressure gradients will
relax a bit over the region, decreasing the surface wind
velocities through at least Saturday.

&&

.AVIATION...VFR conds durg entire prd. Few clds FL020...FL030...
FL050...Isold SHRA en route btw ERN PR and NRN Leeward Islands. Aft
06/16z chance of SHRA/Isold TSRA W/MVFR CIG psbl at TJMZ...and VCSH
TJBQ...Elsewhere VFR. Sfc winds 5-10 kts...BCMG 15-20 kts except
w/local seabreeze variations aft 06/14z. L/lvl winds mainly FM E blo
FL150...BCMG FM SW abv FL300.

&&

.MARINE...Small craft should exercise caution across most of the
local waters due to seas up to 6 feet and winds up to 20 knots.
There is a moderate risk of rip currents across the North, East
and South coasts of Puerto Rico, as well as Vieques, Culebra and
Saint Croix USVI.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 90 81 91 80 / 20 20 20 10
STT 90 80 91 79 / 30 30 30 30