Caribbean - Central America Weather

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
151 PM AST Wed Oct 19 2016

.SYNOPSIS...A persistent band of moisture out of the south
associated with a low pressure north of the Windward Passage
tonight will slowly dissipate overnight with drier weather to
follow on Thursday. Patches of moisture will move through the area
into early next week on more easterly trade winds.

At upper levels...A NE-SW ridge of high pressure will migrate to
Hispaniola over the weekend and then yield to a passing shortwave
traveling east late Monday night into Tuesday. The ridge will
return to Puerto Rico by Thursday.

At mid levels...A ridge extending into the Caribbean out of a
high pressure northeast of the Leeward Islands will cross Puerto
Rico Friday. High pressure will then continue over the Caribbean
and the Greater Antilles chain through early next week.

At lower levels...High pressure ridging into the northeast
Caribbean Sea from a moderate high in the north central Atlantic
Ocean will pull north and join high pressure over the coast of
South Carolina Sunday night while weak N-S troughing moves east
toward the local area. During the rest of the week high pressure
builds east into the western Atlantic generating a steady easterly
trade wind flow.

&&

.DISCUSSION...A persistent band of showers and thunderstorms
associated with a trough that has extended out of a low over the
Bahama Islands north of the Windward passage moved out of the Mona
Channel this morning and over the western end of Puerto Rico
during the day. With moisture also migrating out of the Caribbean
Sea to the south, eventually the whole island, and parts of
Culebra and Vieques received at least some rain. Gusty winds were
reported in various parts of Puerto Rico, although no damage has
been reported so far. The Guanajibo river was slowly approaching
flood stage of 20 feet again and was within 6 inches as of 1:45 PM
AST. The rain that has fallen is expected to produce no more than
minor flooding on the Guanajibo.

The rain band is expected to dissipate and possibly reform over
Hispaniola on Thursday leaving considerably less wet weather for
Puerto Rico Thursday. As high pressure connects north of the area
winds will become more easterly and showers will return to a more
seasonal and limited pattern. Moisture reaches a minimum on
Sunday, but slowly recovers through Thursday of next week.

&&

.AVIATION...TSRA/SHRA across mainland PR will continue to impact
the flying area of all PR terminals through the early evening hours.
TEMPO mvfr at TJSJ and TJPS with gusty winds up to 30 kts possible
with TS. -RA and VCTS elsewhere in PR. Some of this activity could
spread later into the flying area of the USVI terminals. But mainly
VFR expected. Low level winds expected from the S-SE at 8-20 kts
with higher gusts near showers and thunderstorms.

&&

.MARINE...Marine conditions are slowly subsiding but buoy 41043 is
still over 7 feet and the buoy at Rincon is now close to 6 feet.
All areas should be below small craft advisory conditions by
Thursday afternoon. Small craft advisory conditions are not
expected to return before Tuesday.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 79 90 78 92 / 20 30 20 20
STT 79 89 81 85 / 20 20 30 30

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
510 AM AST Thu Oct 20 2016

.SYNOPSIS...The chance of widespread shower and thunder activity
will continue to decrease across the forecast area as an upper
trough across the western Atlantic and into the Greater Antilles
weakens, and a ridge pattern aloft builds across the eastern
Caribbean and over the local islands. A prevailing southeasterly
wind flow will bring warm to hot temperatures across the northern
slopes of Puerto Rico during the next few days.

&&

.DISCUSSION...Variably cloudy skies prevailed across the forecast
area with passing showers observed across the local waters as well
as the southern coastal areas of PR. Minimum temperatures were
between the upper 70s and low 80s under a light southerly wind
flow.

As a mid to upper level trough across the western Atlantic and
into the Greater Antilles weakens, a ridge pattern aloft will
build across the eastern Caribbean with a sharp decrease in
precipitable water. This feature is expected to hold across the
forecast area through Monday. As a result, under a building ridge,
and a decreasing trend in precipitable water --but remaining in
the normal range-- locally induced afternoon showers and
thunderstorms are expected each day. These showers and thunderstorms
will be focused over, north and northwest of the Cordillera
Central today through Saturday under a southeasterly wind flow. In
fact, this southeasterly wind flow will also result in warm to hot
temperatures across the northern slopes of Puerto Rico during the
next few days. Trade winds will return to the forecast area Sunday
and early next week, focusing afternoon showers and thunderstorms
over west PR Sunday and Monday and also providing relief to the
expected warm to hot temperatures.

Ridge aloft will weaken early next week as a broad trough moves
into the west and central Atlantic. Its associated surface
boundary will induce a surface trough east of the forecast area
that will result in moisture pooling across the eastern Caribbean.
As a result, the chance of shower and thunder activity will once
again increase by midweek next week.

&&

.AVIATION...VFR conds expected across the local terminals through
20/13Z with CIGS at around FL120. Winds expected to be light and
variable through 20/13Z...becoming mainly southeasterly thereafter
at around 10kt. VCSH across the terminals today...mainly for the
USVI and TJBQ/TJMZ. Possible VCTS for TJBQ after 20/17Z. Winds
becoming light and variable again after 21/00Z.

&&

.MARINE...Marine conditions will continue to improve, however
hazardous seas are still expected this morning across the
Atlantic offshore waters and the Mona Passage. Seas 5 to 7
feet with occasional seas up to 9 feet but subsiding.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 91 78 91 78 / 30 10 40 20
STT 89 80 89 81 / 20 30 30 30

[HurricaneFan]

I see a Tropical Wave between 35W and 40W now.
Any chance of it reaching the Islands?

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
229 PM AST Thu Oct 20 2016

.SYNOPSIS...Mid to upper ridge will continue to build from the
east through the weekend. Upper trough across the bahamas will
continue to weaken. A polar upper trough will exit the U.S. late
in the weekend with a short wave moving close to the area by early
next week. Southeasterly wind flow will continue through at least
Friday becoming more east to southeast and then east-northeast by
Monday. Warmer than normal temperatures expected during the next
few days due to southerly winds.


&&

.DISCUSSION...Fair weather conditions with mostly sunny skies prevailed
during the day across the forecast area. A few isolated morning
showers were noted over coastal areas of southern PR and over the
surrounding waters of the U.S. Virgin Islands but rainfall was not
significant. It was warm along the northern coast of PR with
temperatures reaching the low to mid 90s around noon. For the rest
of the afternoon hours a couple of showers could still develop
over the mountain ranges and NW quadrant of PR. Southerly winds
can bring brief periods of light showers across the USVI and the
southeastern sections of PR through early Friday morning.

As ridge pattern builds aloft expect trade wind cap to limit
shower activity through the weekend, with mostly diurnally induced
afternoon showers favored by sea breeze convergence over the
interior and northwest sections of PR. Across the USVI, mostly
fair weather conditions will prevail with streamers developing
each day. As polar trough and associated short wave moves near the
forecast area by early next week the ridge will weaken and
moisture is expected to increase once again across the forecast
area.


&&

.AVIATION...VFR conds will continue through 21/16z at all TAF sites,
except for very brief MVFR CIGS in SHRA vcnty TNCM/TKPK til 20/21z.
Winds SE up to 12 kt. SHRA/TSRA just W-NW of local area.


&&

.MARINE...Small craft should exercise caution as seas of 4-6 feet
will continue through at least tonight across the Atlantic waters
and Mona Passage. Seas should continue to subside during the next
few days. High rip current risk continues for the much of the
northern beaches of the islands.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 78 91 78 93 / 10 40 20 20
STT 80 89 81 86 / 30 30 30 30

&&

[HurricaneFan]

I hear the forecast saying moisture could return to the Islands by early next week?
Could the Tropical Wave around 40W be a contributer to that?

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
545 AM AST Fri Oct 21 2016

.SYNOPSIS...A mid to upper level ridge will continue to build
across the forecast area as trough aloft across the southwest
Atlantic continues to weaken. A surface high pressure across
the north central Atlantic will continue to promote a gentle
to moderate southeasterly wind flow today...becoming easterly
the upcoming weekend. The prevailing southeasterly wind flow
will continue to result in warm to hot temperatures across
the northern slopes of Puerto Rico today.

&&

.DISCUSSION...Variably cloudy skies prevailed across the forecast
area with passing showers observed across the local waters as well
as the southern coastal areas of PR. Minimum temperatures were
between the upper 70s and low 80s under a light southeasterly
wind flow.

Under a building ridge pattern and precipitable water near the
normal range, continue to expect a few passing showers across
the windward areas, followed by locally induced afternoon showers
and thunderstorms. These afternoon showers and thunderstorms will
be focused north and northwest of the Cordillera Central today
and Saturday under a southeasterly wind flow. In fact, this
southeasterly wind flow will continue to result in warm to hot
temperatures along the northern slopes of Puerto Rico during the
next two days or so.

Trade winds will return to the forecast area Sunday and early
next week, focusing the afternoon showers and thunderstorms over
west PR Sunday and Monday and also providing relief to the
expected warm to hot temperatures. Moisture is expected to pool
across the forecast area Monday afternoon and continue throughout
the end of next workweek as the ridge pattern aloft weakens in
response to a broad trough moving across the west and central
Atlantic. Its associated surface boundary will induce a surface
trough across the eastern Caribbean which is expected to increase
the chance of shower and thunder activity across the local
islands.

&&

.AVIATION...Passing -SHRA possible at TJPS/TIST/TISX, as well as
in the VCTY of TJSJ early this morning, but most of the SHRA are
expected over the surrounding waters. After 21/16z, SHRA/TSRA
expected along and to the west of the Cordillera Central, to
result in brief MVFR at TJMZ/TJBQ, afternoon SHRA are possible too
at TJSJ/TIST/TISX. This activity is expected til 21/22z. Winds
expected from the SE at less than 15kt, however locally higher
in/around SHRA/TSRA, and sea breeze variations aft 21/13z.

&&

.MARINE...Tranquil marine conditions are expected to prevail
during the next few days with seas below 5 feet and winds up to
15 knots. An increase in shower and thunder activity expected
early next workweek as a surface trough dominates the eastern
Caribbean.

&&

.CLIMATE...A record warmest low set at the primary climate data
sites yesterday. A record warmest low of 82 degrees was set at
San Juan Area. This broke the old record of 79 set back in 2014.
A record warmest low of 84 degrees was set at Cyril E. King
Airport in St Thomas. This broke the old record of 81 set back in
1998. This warmest low also tied the warmest low observed for any
given day. A record warmest low of 82 degrees was set at Henry E.
Rohlsen airport in St Croix. This broke the old record of 81
degrees set back in 1987.

&&

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

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
135 PM AST Fri Oct 21 2016

.SYNOPSIS...Ridge pattern aloft across the eastern Caribbean will
continue to hold through the weekend. A polar trough will enter the
western Atlantic early in the weekend and weaken the ridge pattern
by early next week. At lower levels, an area of low pressure north
of the Bahamas will merge with a frontal system during the next day
or so and the frontal boundary is expected to remain north of the
area. Southeast winds and warm/hot temperatures are expected through
at least Saturday. Meanwhile a strong surface high pressure behind
the front will establish across the western Atlantic and shift
winds from the northeast by Sun-Mon. At the same time an induced
surface trough is forecast to develop across the eastern
Caribbean. A tropical wave along 45W is forecast to move close or
to the northeast of the area by mid-late week next week.


&&

.DISCUSSION...Sunny to partly cloudy skies were observed
during the morning hours across the islands. Passing showers were
noted with a southeasterly wind flow across sections of the U.S.
Virgin Islands and the southern/eastern portions of PR. Over a
quarter of an inch of rain was reported with these showers across
southeastern PR. Temperatures reached the lower 90s across coastal
areas just before noon. Afternoon showers and isolated thunderstorms
induced by local effects and sea breeze convergence were
developing across the interior and northwest sections of PR. This
activity is expected to diminish around sunset.

As ridge pattern holds early in the forecast cycle, fair weather
conditions are expected to prevail with moisture increasing later on
Sunday. A somewhat drier day is expected on Saturday with localized
afternoon convection over the interior and western sections of PR.
Streamers developing off the U.S. Virgin Islands are expected with
some reaching coastal areas of eastern PR. As southeasterly wind
flow continues on Saturday, resulting in warm to hot temperatures
along the northern slopes of Puerto Rico.

As surface high pressure establish to the west/north of the area and
the frontal boundary hangs to the north of the forecast area, trade
winds will become more northeasterly by Monday. Also, as polar trof
weakens the upper ridge moisture will increase late Sunday into
early next week. An induced surface trough is forecast to develop
across the eastern Caribbean. Therefore, trade wind showers will
increase across the Atlantic waters reaching the northern coastal
areas of the islands and enhancing afternoon convection along the
mountain ranges of PR during the afternoon hours through at least
mid week next week. Models are indicating that precipitable water
will remain high across the forecast area through the long term
period. Models are in disagreement with development of the tropical
wave along 45W, however, moisture associated to the wave is expected
to reach the local area sometime later next week.


&&

.AVIATION...SHRA/TSRA expected along and north of the Cordillera
Central, VCTY SHRA/TSRA at TJMZ/TJBQ till 22z. Winds SE at less than
15kt, however locally higher in/around SHRA/TSRA, then diminishing
to 10 kt or less til 22/14z. SHRA incrg aft 22/18z interior PR and
Leeward Islands with mtn obscurations and brief MVFR conds. Winds
alf bcmg more easterly aft 22/12z up thru FL240 at 10 to 20 kt.


&&

.MARINE...Tranquil seas are expected through the next several days
with guidance indicating seas no higher than 5 feet. Winds will
remain below 15 knots, southeasterly trades will shift more east-
northeast by the end of the weekend through next week in response to
surface high pressure across the western Atlantic. Scattered showers
and isolated thunderstorms are expected to increase early next week
across the waters due to a surface trough.


&&

.CLIMATE...A record high temperature of 94 degrees was set at the San
Juan area Today. This breaks the old record of 92 set in 2010.

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
558 AM AST Sat Oct 22 2016

.SYNOPSIS...
Ridge pattern aloft across the eastern Caribbean will continue to
hold through the weekend. As a polar trough moves across the
Western Atlantic on Sunday, the ridge pattern is expected to
weaken by early next week. At lower levels, a frontal system is
expected to moves across the Western Atlantic and remain to the
north of the local islands during the weekend and early next week.
As a result, moisture is expected to pool across the local area.
Therefore, expect passing showers across the windward sections of
the U.S. Virgin Islands and Puerto Rico during the overnight and
early morning hours, followed by afternoon showers and
thunderstorms mainly across the interior and to the west of Puerto
Rico each day. Although, easterly winds are expected to return,
light winds and warm/hot temperatures are expected through the
weekend.

&&

.DISCUSSION...
Satellite imagery showed a layer of mid to upper level clouds over
the islands. Also, the Doppler radar detected a showers across the
surrounding waters, but some of them moved across the windward
sections of the U.S. Virgin Islands and Puerto Rico. However,
rainfall accumulations were minimal. Once again, the minimum
coastal temperatures were around low 80s.

Under a ridge pattern and enough low level moisture, continue to
expect a few passing showers across the windward areas, followed
by locally induced afternoon showers and thunderstorms. The
afternoon activity should focused across the interior and
northwestern sections of Puerto Rico, as well as downwind from the
U.S. Virgin Islands. In addition, some showers could develop
downwind from El Yunque to affect the San Juan Metro Area late
this morning and into the afternoon. By this afternoon a
southeasterly wind flow will result in warm to hot temperatures
along the northern slopes of Puerto Rico.

A frontal boundary is expected to remain to the north of the local
area through the early part of the upcoming week. A strong surface
high pressure behind this front is expected to establish across
the western Atlantic. This pattern will shift winds from the
northeast Sunday-Monday. Although, trade winds will return to the
forecast area by Sunday, light winds will continue to result in
warm/hot temperatures, with afternoon showers and thunderstorms
focusing across and to the west of the Cordillera Central by early
next week.

&&

.AVIATION...
VFR conditions are expected to prevail at all TAF sites
through 22/16z. After 22/16Z, brief periods of MVFR conditions with
mountain obscurations can be expected across TJMZ and TJBQ in
SHRA/isolated TSRA. Low level winds will continue mainly from the
southeast at 10 kts.

&&

.MARINE...
Tranquil seas are expected through the next several days with
guidance indicating seas no higher than 5 feet. Winds will remain
below 15 knots.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 91 78 90 79 / 20 30 30 50
STT 89 82 89 82 / 20 30 30 50

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
100 PM AST Sat Oct 22 2016

.SYNOPSIS...Ridge pattern aloft across the eastern Caribbean will
continue to hold through the weekend. Ridge pattern is expected
to weaken by early next week. At lower levels, a frontal system is
expected to moves across the Western Atlantic and remain to the
north of the local islands during the weekend and early next week.


&&

.DISCUSSION...High level cloudiness prevailed across the local
area today. Very little shower activity was observed over land
areas. A relative drier airmass has moved across the region today.
Latest TJSJ 22/12z sounding showed precipitable water values of
1.71 inches. However, the limited low level moisture will combine
with daytime heating and local effects this afternoon to induce
some showers and a couple of thunderstorms over western interior
and northwest sections of Puerto Rico. This relatively dry weather
pattern is expected to persist until early next week.

Moisture is expected to pool across the local area by mid week.
Therefore, expect passing showers across the windward sections of
the U.S. Virgin Islands and Puerto Rico during the overnight and
early morning hours, followed by afternoon showers and
thunderstorms mainly across the interior and to the west of Puerto
Rico each day. Although, easterly winds are expected to return,
light winds and warm/hot temperatures are expected through the
weekend. At this time, no significant weather events are forecast
to affect the local region in the long term.

&&

.AVIATION...VFR conditions are expected to prevail across the
local flying area through the rest of this afternoon and tonight.Brief
periods of MVFR conditions with mountain obscurations can be
expected across TJMZ and TJBQ in SHRA/isolated TSRA through
22/22z. Low level winds will continue mainly from the southeast
at 10 kts.

&&

.MARINE...Seas up to 4 feet and winds up to 15 knots are expected
over the coastal waters.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 78 90 79 89 / 30 30 50 50
STT 82 89 82 89 / 30 30 50 50

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
549 AM AST Sun Oct 23 2016

.SYNOPSIS...
Ridge pattern aloft continues to weaken, as a polar trough moves
across the Western Atlantic. At lower levels, a frontal system is
expected to moves across the Western Atlantic and remain to the
north of the local islands through mid week. As a result,
moisture is expected to pool across the local area. Therefore,
expect passing showers across the windward sections of the U.S.
Virgin Islands and Puerto Rico during the overnight and early
morning hours, followed by afternoon showers and thunderstorms
mainly across the interior and across the north and south slopes
of the Cordillera Central of Puerto Rico each day.

&&

.DISCUSSION...
The mid to upper level cloud layer dissipated overnight, and the
Doppler radar detected trade wind showers across the local waters.
Some of these showers moved across the windward sections of the
U.S. Virgin Islands and Puerto Rico, but without any significant
rainfall accumulation. The coastal minimum temperatures were in
the upper 70s and low 80s and the wind was from the east at less
than 10 mph.

Showers are expected to continue across the coastal waters and the
windward sections of the islands this morning. Then, the
available moisture will combine with daytime heating and local
effects to induce showers and a couple of thunderstorms over the
interior and across the north and south slopes of the Cordillera
Central of Puerto Rico. Showers and thunderstorms should last
longer due to the light winds across the region. Therefore, a
slight to moderate risk of flooding is expected across these
sections.

A surface induce trough is expected to reach the local islands on
Monday and Tuesday. Moisture is expected to pool across the local
area through at least mid week. Therefore, shower activity should
increase during these days with more frequent trade wind showers
across the windward sections of the islands overnight and early
in the morning, followed by afternoon showers and thunderstorms
across the interior and to the west of Puerto Rico each day. In
addition, more seasonal daytime temperatures can be expected
during this week.

&&

.AVIATION...
VFR conditions are expected to prevail at all TAF sites
through 23/16z with VCSH at JSJ/IST/ISX and Leeward terminals. After
23/16Z, periods of MVFR conditions possible at all PR TAF sites in
SHRA/isolated TSRA under a light and variable wind flow at 10 knots
or less. Mountain obscurations across central PR expected.

&&

.MARINE...
Tranquil marine conditions are expected to continue through the
next this week with seas below 5 feet and winds around 15 knots.
Today`s rip currents risk is low across the local beaches.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 88 79 89 79 / 30 50 50 50
STT 88 79 89 78 / 30 50 50 50

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
139 PM AST Sun Oct 23 2016

.SYNOPSIS...Ridge pattern aloft continues to weaken, as a polar
trough moves across the Western Atlantic. At lower levels, a
frontal system is expected to moves across the Western Atlantic
and remain to the north of the local islands through mid week. As
a result, moisture is expected to pool across the local area.

&&

.DISCUSSION...Partly to mostly sunny skies prevailed across the
local area late this morning. Limited shower activity was
observed. However, early this afternoon, a line of showers and
thunderstorms affected the U.S. Virgin Islands and eastern Puerto
Rico. This area of moisture will continue to move across Puerto
Rico the rest of this afternoon. This moisture in combination with
daytime heating and local effects will produce a round of showers
and thunderstorms over central interior sections of Puerto Rico
this afternoon. Showers and thunderstorms should last longer due
to the light winds across the region.

For the rest of the week, as ridge pattern aloft continues to
weaken, an increase in shower and thunderstorm activity is
expected. Trade winds are expected to shift more northeasterly by
Tuesday, which will bring patches of low level moisture across the
region. In the long term, no significant weather events are
forecast to affect the region at this time.

&&

.AVIATION...Mostly VFR conditions will prevail across the Leeward
taf sites with only vcsh expected. Brief periods of MVFR conditions
are possible across the USVI taf sites as well as across all PR TAF
sites in SHRA/isolated TSRA until 23/23Z under a light and variable
wind flow at 10 knots or less. Mountain obscurations across central
PR expected.

&&

.MARINE...Tranquil marine conditions are expected to continue
through mid this week with seas below 5 feet and winds around 15
knots. Today`s rip currents risk is low across the local beaches.



&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 79 89 79 88 / 50 50 50 50
STT 79 89 78 89 / 50 50 50 50

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
534 AM AST Mon Oct 24 2016

.SYNOPSIS...Upper level ridge will weaken over the next few days
as a broad polar low moves over the East Coast of USA and the
Northwest Atlantic. This upper level pattern will hold through at
least midweek...then an upper level ridge builds again over the
Eastern Caribbean the second part of the week. At low levels...
a frontal boundary about 450 miles northeast of Puerto Rico this
morning will stall north of the islands over the next couple of
days. However...the shearline/pre-frontal trough will keep the
area fairly moist and unstable most of the work week.

&&

.DISCUSSION...The shearline/pre-frontal has induced the development
of showers and thunderstorms across the regional waters and portions
of the local islands during overnight. Some showers have moved inland
across the north and east coastal sections of Puerto Rico...producing
up to one quarter of an inch in some spots. Northeast flow at low
levels will continue to favor passing showers across the north coastal
sections of Puerto Rico the rest of the morning. Then...high resolution
models suggest deep convection across the Central Interior...West...
Southwest and South Central Puerto Rico this afternoon. As a result...
urban and small stream flooding will be possible across portions
of the Southwest Quadrant of Puerto Rico.

Over the next several days, environmental conditions remain
favorable for shower and thunderstorm activity under the influence
of the shearline /pre-frontal trough and a short-wave trough
aloft. Therefore...a few round of convection is possible everyday
across portions of the islands through at least midweek.
Although...upper level ridge is forecast to build over the region
later in the week...moisture content remains high as a tropical
wave crosses the local are between Thursday and Friday. In
summary...moist and unstable pattern will likely prevail most of
the work week under the influence of the shearline/prefrontal
trough and then the tropical wave.

&&

.AVIATION...VFR conditions expected early in the forecast period.
However, TSRA/SHRA over the Atlantic waters and northeasterly
steering winds could bring some showers near the northern terminals
of the islands with brief periods of MVFR conditions. After 16z
SHRA/TSRA will develop arnd the Cordillera Central and downstream
from El Yunque. Brief MVFR expected at TJMZ/TJPS. Mtn obscurations
are expected. Winds NE at 5-15 kt up through FL200. Sea breeze
variations aft 14z.

&&

.MARINE...Tranquil marine conditions will prevail across the local
waters most of the week. Winds of 10-15 knots and seas of 3-5 feet
are forecast through at least midweek. Then...winds will subside to
5-10 knots as a surface low moves northeast of the islands late this
week. No Small Craft is anticipated during the work week.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 89 79 88 77 / 50 50 50 50
STT 89 78 89 78 / 50 50 50 50

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
405 AM AST Tue Oct 25 2016

.SYNOPSIS...Short-wave upper level trough over Hispanola will move
westward over the region today. This trough aloft combined with
the proximity of the shearline/pre-frontal trough will enhance the
moisture convergence across the local islands through Thursday.
Mid to upper level ridge will build over the region from Friday
through the weekend...limiting the showers and thunderstorm
coverage across the local islands.

&&

.DISCUSSION...Moist and unstable conditions will continue to
prevail across the forecast area under the influence of the upper
level trough and the shearline/pre-frontal trough. Although...the
frontal boundary will remain far northeast of the local area, the
shearline will continue to affect the local weather conditions
over the next couple of days.

Today and tonight...East-northeast winds at low levels will
continue to favor passing showers across the coastal waters and
portions of the north and east coastal sections of the islands
this morning. Then...afternoon convection will be likely once
again across the Central Interior...West...Southwest and South
Central Puerto Rico. The soils across these areas are fairly
saturated and rivers/streams are running high...therefore any
additional heavy rainfall will result in urban and small stream
flooding especially late in the afternoon.

The rest of the week...environmental conditions remain favorable
for shower and thunderstorm activity through Thursday. Therefore...
expect passing showers affecting the windward areas of PR and USVI
at night and early in the morning...followed by a few rounds of
convection across the Western half of PR each afternoon. Conditions
will gradually improve from Friday into the upcoming weekend as a
mid-upper level ridge builds over the forecast area. This dry and
more stable air mass will result in less shower and thunderstorm
coverage across the local islands later in the week.

Unstable pattern is possible again by midweek next week when an
upper level trough amplifies over the Western Atlantic.

&&

.AVIATION...Mainly VFR conds expected across much of the forecast
period. However, trade wind showers on ENE wind flow could reach
portions of the nrn leewards/USVI and east/northeast PR thru 14z.
Then between 16z-22z, SHRA/TSRA will develop over and downwind of
the Central Mtn ranges of PR. Brief MVFR expected at TJMZ/TJPS.
Also, streamers developing off the USVI could result in brief MVFR
conds during the afternoon hours. SFC winds ENE at 5-15 kt. Sea
breeze variations aft 14z.

&&

.MARINE...Tranquil marine conditions will continue to prevail
with seas up to 4 feet and winds 10 knots or less except in the
Atlantic Offshore waters and passages where winds will be 10 to 15
knots and seas up to 5 feet. No Small Craft Advisories are
anticipated the rest of the week.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 88 78 88 78 / 50 50 30 40
STT 87 78 87 78 / 50 50 30 40

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
150 PM AST Tue Oct 25 2016

.SYNOPSIS...Upper level trough across the region will move
northeastward and away from the local islands tonight. A frontal
trough will remain close to the region for the next few days
maintaining abundant low level moisture across the local islands.
Upper level ridge will build again over the northeast Caribbean by
Friday.

&&

.DISCUSSION...A pre-frontal trough just north of the region will
maintain a moist an unstable weather pattern across the local
islands until at least Thursday. Doppler weather radar detected
scattered to numerous showers and isolated thunderstorms across
central interior, western and northwest sections of Puerto Rico
early in the afternoon. This activity is expected to continue for
the rest of the afternoon and until the early evening hours.
Soils are well saturated due to the previous days rainfall and
therefore Urban and Small Stream flooding and river flooding are
possible late this afternoon and evening across central interior,
Western and northwest of Puerto Rico.

Model guidance suggests that the frontal boundary remnants will
remain north but close to the region for the next few days. This
moisture will maintain a moist and unstable weather environment,
favorable for the development of shower and thunderstorm activity
across the local islands until at least Thursday and possible
beyond. Showers and thunderstorms are therefore expected and
Thursday across portions of the local islands. A weak tropical
wave, near 60 West this afternoon will continue to move westward,
passing mostly south of the local islands Wednesday and Thursday.
This feature will aid to maintain the wet weather pattern across
the area.

&&

.AVIATION...Brief MVFR with mountain obscurations expected at
TJMZ/TJPS until at least 25/23Z. After 25/23Z mostly VFR
conditions will prevail across the local flying area with vicinity
SHRA across the Leewards, USVI and TJSJ taf sites. After 26/16Z
SHRA/TSRA will develop again around Cordillera Central and
downstream from El Yunque. Winds remain from E-NE at 5-15 kt with
sea breeze variations after 26/14Z.

&&

.MARINE....MARINE...Tranquil marine conditions are expected to continue
through mid this week with seas up to 5 feet and winds around 15
knots. Moderate risk of rip currents expected across most of the
northern beaches of Puerto Rico.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 78 88 79 88 / 50 50 40 40
STT 78 89 78 88 / 50 50 40 40

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
551 AM AST Wed Oct 26 2016

.SYNOPSIS...Upper trough will continue to exit the region Today
as ridge builds from the central Caribbean and holds through the
end of the week. Another short wave trof is forecast to move aloft
from the western Atlantic by early next week. At lower levels,
frontal boundary to the north of the area and troughiness will
continue to keep a moist environment for the next couple of days.
An easterly wave will move mainly south of the area through
Thursday. Surface high across the western Atlantic will maintain
an east to northeast wind flow through the end of the work week.
East to southeast winds return during the weekend.


&&

.DISCUSSION...Scattered showers on a northeasterly wind were
observed across the coastal Atlantic waters with a few reaching
coastal areas and the northern U.S. Virgin Islands. However,
mostly clear skies with a few clouds prevailed across the rest of
the forecast area. For the rest of the morning hours, showers are
expected to increase across the northern half of the island.
Enough moisture will lead to another round of showers and
thunderstorm development over the mountains and to the
west/southwest of them during the afternoon hours. A similar
weather pattern is expected each day with easterly wave/steering
east winds favoring convection over the western side of the island
during the afternoons. During the weekend as winds turn more from
the southeast, afternoon convection should focus across the
northwest quadrant of the island.

Moisture content with normal to above normal PWAT will continue
for the next several days even as ridge builds aloft. There seems
to be a slight drop of moisture content during the weekend but
showers and isolated thunderstorms are still expected. The
easterly wave is currently producing scattered showers and
thunderstorm activity to the east of Guadeloupe. This wave is
forecast to move east to the south of the area and aid to the
development of showers and thunderstorms across the offshore
Caribbean waters and increase the available low level moisture
through Thursday. For early next week, another short wave trof
will move from the western Atlantic weakening the ridge and
bringing more unstable conditions.

&&

.AVIATION...VFR conds expected at most of the terminals durg the
forecast period. However, NE trade winds will push SCT SHRA near
TJBQ, TJSJ and TIST thru at least 14Z. As a result...Brief MVFR in
passing SHRA are possible at times. SHRA/TSRA fcst to develop ovr
and downwind of the Cordillera Central of PR. MVFR and mountain
obscurations possible in and around TJMZ/TJPS between 26/17Z-21Z.
NE winds of 10-15 kt will prevail below FL100.


&&

.MARINE...Seas will continue 3-5 feet overall across most of the
waters...increasing to 6 feet by Thursday across the offshore
Atlantic waters. East to northeast winds will continue between
5-15 knots. Turning east to southeast during the weekend. There is
a moderate risk of rip currents across the Atlantic exposed
beaches of the islands.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 87 78 88 79 / 50 30 30 40
STT 89 79 88 78 / 50 30 30 40

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
151 PM AST Wed Oct 26 2016

.SYNOPSIS...Another short wave trof is forecast to move aloft
from the western Atlantic by early next week. At lower levels,
frontal boundary to the north of the area and troughiness will
continue to keep a moist environment for the next couple of days.
An easterly wave will move mainly south of the area through
Thursday. Surface high across the western Atlantic will maintain
an east to northeast wind flow through the end of the work week.
East to southeast winds return during the weekend.

&&

.DISCUSSION...an area of moderate to heavy showers moved across
the San Juan metropolitan area this morning. Around one inch of
rainfall was observed. A slot of drier air can be seen on satelite
images late this morning and early this afternoon. This area of
drier air has limited the shower and thunderstorm development
compared to yesterday. However, by noon showers and thunderstorms
started to develop across the southern slopes of Puerto Rico as
available moisture combined with daytime heating and local
effects. Therefore, scattered to numerous showers are expected the
rest of this afternoon across these areas. For tonight, some
passing showers are expected to affect mainly the north and east
sections of Puerto Rico and the northern U.S. Virgin Islands.

For the weekend an upper level ridge will dominates the local
area, which will limit somewhat the chances for showers and
thunderstorms across the area. For the long term, although the GFS
is showing a very wet pattern by the end of next week, still too
early to know if this solution will verify or not.

&&

.AVIATION...VFR conds expected through the local terminals with
persistent VCSH/VCTS at TJMZ and TJPS after 26/18Z as SHRA/TSRA is
expected across the interior, West, and South PR. Passing VCSH
possible for the rest of the local terminals. Winds continuing from
the NE at about 10KT with sea breeze variations through today.
Weather conditions to improve after 27/00Z. Winds becoming lighter
overnight.

&&

.MARINE...Seas up to 5 feet and winds up to 15 knots are expected.
Seas are expected to increase by late Thursday into Friday across
the offshore Atlantic waters.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 78 88 79 89 / 30 30 40 40
STT 79 88 78 88 / 30 30 40 40

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
526 AM AST Thu Oct 27 2016

.SYNOPSIS...Mid to upper level ridge will hold over the region
through the weekend. This ridge will limit somewhat the shower
and thunderstorm activity during the weekend. At low level...a
tropical wave will move across the forecast area today...inducing
the development of scattered to numerous showers over portions of
Puerto Rico and the U.S. Virgin Islands later today. Very moist
and unstable pattern is possible by midweek next week as a high
amplitude upper level trough moves over the region.

&&

.DISCUSSION...Surface analysis as well as satellite imagery showed a
tropical wave moving across the Anegada Passage early this
morning. This wave will move westward across the forecast area
today...increasing the potential for showers and thunderstorms.
Northeast winds at low levels will continue to favor passing
showers across the coastal waters and the windward side of the
islands the rest of the morning. Then...winds will shift from the
east-southeast early this afternoon...focusing the afternoon
convection over portions of the Cordillera Central and Western
Puerto Rico. Above normal moisture combined with high convective
instability associated with the tropical wave will result in
periods of heavy rainfall. Any heavy rainfall over saturated
soils of the Central and Western Puerto Rico...will result in
urban and small stream flooding as well as mudslides in some
spots of Puerto Rico.

Conditions will improve somewhat from Friday into the upcoming
weekend as a mid-upper level ridge builds over the forecast area.
This dry and more stable air mass will reduce the shower and
thunderstorm coverage across the local islands through the end of
the week. Moist and unstable pattern is possible again by midweek
next week as an upper level trough amplifies over the Western
Atlantic.

&&

.AVIATION...VFR conds expected through the local terminals with
passing -SHRA at TJSJ/TIST/TJBQ the rest of the morning. Afternoon
SHRA/TSRA are possible btwn 27/16z-22z across the interior and
across the West Half portion of PR. This activity could produce
brief MVFR conds at TJPS/TJMZ/TJBQ. Elsewhere frequent VCSH are
possible. NE Winds around 10kt will prevail thru 27/15Z, gradually
veering to the ESE at 15kt during the afternoon and evening.

&&

.MARINE...A moderate swell NNE of 4-6 ft at 10 sec will continue
to move across the local Atlantic Waters and Caribbean Passage
over the next few days. Seas will subside somewhat during the
weekend and early next week. Seas are expected to remain below
advisory levels through the forecast period. However...Small craft
operators should exercise caution through Friday due to seas up to
6 feet across the offshore Atlantic Waters.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 88 79 89 78 / 30 40 40 20
STT 88 78 88 78 / 30 40 40 20

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
143 PM AST Thu Oct 27 2016

.SYNOPSIS...A seasonable weather pattern will prevail Friday and
into the upcoming weekend with locally induced showers and Tstorms
under a mid to upper level ridge pattern. Rainy conditions possible
next week as the aforementioned ridge pattern weakens and a trough
develops north of the area. Meanwhile, tropical wave will continue
to move away from the local islands tonight.

&&

.DISCUSSION...As a tropical wave moves away from the forecast
area this evening and tonight, the chance of showers and isolated
Tstorms will decrease. However, continue to expect shower and
thunder development over and west of the Cordillera Central through
the afternoon hours followed by a few passing showers across
windward areas overnight.

Friday through the upcoming weekend, a seasonable weather pattern
is expected to prevail with locally induced afternoon showers and
thunderstorms each day. Showers and Tstorms will be focused across
central and northwest PR as well as portions of the San Juan Metro
Area under a gentle southeast wind flow. Although widespread
convection is not expected at this time, urban and small stream
flooding still possible Friday and the upcoming weekend due to
already saturated soils and slow moving showers/Tstorms.

The ridge aloft will then erode next week as a broad upper level
trough develops across the tropical Atlantic and into the Caribbean
basin. This will result in deep tropical moisture pooling across
the forecast area Tuesday-Saturday with a rainy weather pattern
possible.

&&

.AVIATION...Afternoon SHRA/TSRA are possible till 27/22z across
the interior and West Half of PR. This activity could produce
brief MVFR conds at TJPS/TJMZ/TJBQ. Elsewhere frequent VCSH are
possible. Easterly winds at 10kt during the afternoon and evening,
becoming light and variable overnight.

&&

.MARINE...A moderate swell NNE of 4-6 ft at 10 sec will continue
to move across the local Atlantic Waters and Caribbean Passage
over the next few days. Seas will subside somewhat during the
weekend and early next week. Seas are expected to remain below
advisory levels through the forecast period. However...Small
craft operators should exercise caution through Friday due to
seas up to 6 feet across the offshore Atlantic Waters.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 79 89 78 89 / 20 20 40 40
STT 80 87 79 87 / 30 30 40 40

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
503 AM AST Fri Oct 28 2016

.SYNOPSIS...High pressure ridge will build overhead through
Sunday. Ridge is to then erode on Monday and Tuesday of next week
as a short wave trough is forecast to move across the western
Atlantic and become amplified across the local area by Wednesday
and the remainder of the next work week. Moisture trailing a tropical
wave now crossing the Dominican Republic will continue to exit the
region this morning. Meanwhile a weak ridge will spread across the
region as the surface high over the north central Atlantic sinks
farther southwards into the central Atlantic. This will induce a
light east to southeast trade wind flow across the area. A weak
easterly perturbation east of the northern Leewards will continue
westwards and bring another patch of low level moisture to the
region by Saturday morning.

&&

.DISCUSSION...Passing trade wind showers will continue to affect
the coastal waters and windward sections of the islands during
the early morning hours. For the remainder of the day and into
the upcoming weekend, expect a seasonal weather pattern as the
tropical wave and associated trailing moisture will exit the region
later this morning. However, diurnal effects and local sea breeze
convergence will give way to showers and isolated thunderstorms
across parts of the islands during the afternoon hours. Over Puerto
Rico activity should be focused over the North central and northwest
sections of the island including parts of the San Juan metro area.
Mostly isolated afternoon showers can be expected in and around the
U.S Virgin Islands.

Localized urban and small stream flooding will again remain possible
particularly over parts of Puerto Rico today and during the upcoming
weekend due to already saturated soils and the expected slow moving
afternoon convection.

For the long term...as previously mentioned the ridge aloft is forecast
to erode early next week as a short wave trough becomes amplified and
sink southwards into the Central and eastern Caribbean basin. Consequently
the surface trough will deepen and a low is expected to develop just
north of the region by mid-week. This overall pattern will result in
deep tropical moisture convergence and upper level instability across
the forecast area beginning on Tuesday and continuing through the
remainder of the week. As usual will continue to monitor and see how
this forecast pattern unfolds over the next few days. Regardless, local
soil will remain nearly saturated in most areas across the interior
sections of Puerto Rico. Any additional heavy rainfall over the next
few days may lead to minor urban and small stream flooding as well
as mudslides in areas of steep terrain.

&&

.AVIATION...Mostly VFR conditions expected through 28/16Z across the
local flying area. However, VCSH expected across TISX, TIST, TNCM
and TKPK until 28/14Z. Winds will be mainly light and variable
across PR and USVI terminals until 28/13Z but are expected to
increase after that. Afternoon convection across PR could cause at
least VCTS for TJSJ, TJMZ, and TJBQ after 28/16Z and mtn obscurations
over most of PR.

&&

.MARINE...A slowly subsiding northerly swell of 4-6 ft at 10 sec
will continue to affect the local Atlantic Waters and Caribbean
Passage today through Saturday, followed by gradually improving
conditions on Sunday and into next week. Seas are expected to remain
below advisory levels through the forecast period. However...Small
craft operators should exercise caution today and through early
Saturday due to seas up to 6 feet across the local Atlantic
waters and the Mona passage .

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 90 78 89 77 / 30 40 40 30
STT 88 79 87 79 / 30 40 40 30

[cycloneye]

Area Forecast Discussion
National Weather Service San Juan PR
203 PM AST Fri Oct 28 2016

.SYNOPSIS...Upper level ridge will continue to dominates the
local area through mid week. A deep upper level trough is forecast
to develop across the western Atlantic Tuesday...eroding the
ridge.

&&

.DISCUSSION...A moist southeasterly wind flow prevailed across
the local region today. This moist southeasterly wind flow
enhanced the development of showers and thunderstorms across the
southeast and the northeast sections of Puerto Rico, including the
San Juan metropolitan area. Through 2 pm, 2.38 inches were
recorded at the Luis Munoz Marin International Airport.

The ridge aloft is forecast to erode early next week as a short
wave trough becomes amplified and sink southwards into the Central
and eastern Caribbean basin. Consequently the surface trough will
deepen and a low is expected to develop just north of the region
by mid-week. This overall pattern will result in deep tropical
moisture convergence and upper level instability across the
forecast area beginning on Tuesday and continuing through the
remainder of the week. Regardless, local soil will remain nearly
saturated in most areas across the interior sections of Puerto
Rico. Any additional heavy rainfall over the next few days may
lead to minor urban and small stream flooding as well as mudslides
in areas of steep terrain. Stay tuned.

&&

.AVIATION...MVFR conds will remain possible at PR and USVI TAF
sites till 28/22z as trade wind showers as well as locally
induced SHRA/ isolated TSRA prevails across the area. Elsewhere,
VFR conds expected. ESE winds 10-15 knots with sea breeze
variations till 28/22z becoming light and variable overnight.

&&

.MARINE...seas up to 6 feet and winds up to 15 knots are expected
over the coastal waters.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU 78 89 77 89 / 40 40 30 30
STT 79 87 79 87 / 40 40 30 30