Puerto Rico Weather

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cycloneye
Category 5

Posts: 2,507

Puerto Rico Weather Jan 11, 2017 4:33:35 GMT -6

Quote

Post by cycloneye on Jan 11, 2017 4:33:35 GMT -6

Area Forecast Discussion

National Weather Service San Juan PR

505 AM AST Wed Jan 11 2017

.SYNOPSIS...High pressure in the western Atlantic has brought a

cold front through Puerto Rico and the U.S. Islands with strong

winds, and hazardous marine conditions that will last through at

least the end of the week.

At upper levels...A jet of up to 95 knots will prevail over the

local area through at least Sunday. High pressure will begin

ridging north over Hispaniola until a weak short wave moves

through on Monday.

At mid levels...Low pressure will cut off about 880 miles

northeast of San Juan today moving only about 400 miles southeast

through Friday sending a trough through the area. High pressure

then spreads over the area from the western Caribbean and

continues through the end of next week. Mid levels remain very dry

until Tuesday of next week.

At lower levels...A cold front has passed through the area and

north to northeast flow will continue due to persistent high

pressure in the western Atlantic. Low pressure will deepen about

880 miles northeast of San Juan and play an important role in wave

production for the area, but it will move south and dissipate by

Sunday leaving only a broad stretch of northeasterly winds around

the high by next week.

&&

.DISCUSSION...Winds have continued over the area`s waters with

some stronger winds making it onshore with showers. San Juan had

gusts to 37 mph overnight and 53 hundredths of an inch of rain

since 6 PM AST Tuesday. Showers will continue on the windward side

of the islands through the day with some showers able to cross

through. The back edge of the frontal band moisture is expected to

be through Puerto Rico by evening, but GFS time-height sections

over the area show rich shallow low-level moisture persisting

through much of the forecast period. Flow gradually becomes more

easterly during the next 7 days, but moisture patches continue and

will yield isolated to scattered showers. Because of the long

fetch of winds behind the front and around the high pressure

marine conditions will be the most prominent weather features

through the rest of the week. After a lull tonight, 850 mb winds

will increase to over 30 knots Friday afternoon according to the

GFS and so surface winds will follow suit to a lesser degree.

Winds gradually subside over the week following.

Expect Thursday morning to be the coolest of the next 10 days with

warming of the 1000 to 850 mb layer through Friday followed by

little change in minimum and maximum temperatures.

&&

.AVIATION...BKN-OVC cld lyrs nr Fl022...Fl050...FL080 assocd with

remnants of old frontal boundary will cont to sink southwards

across the flying area durg the nxt 24 hrs. Periods of SHRA, with

ocnl gusty northerly Sfc winds up to 30 kts mainly across the ATL

coastal water and northern half of PR and USVI til at least

11/15z. TEMPO MVFR conds psbl with the passing SHRA. Recent VAD

wind profile from the doppler weather radar TJUA suggest llvl winds

btw 15-25 kts below FL200...bcmg W and increasing with height abv

to max wnd of 70-80 kts nr FL360.

&&

.MARINE...Winds and seas will increase through Saturday with seas

of at least 12 feet in portions of the local Atlantic waters by

Saturday. This is mainly due to a second pulse of swell generated

by the low forming northeast of the area that will arrive early in

the weekend. Small Craft Advisories will remain in all exposed

waters through at least the weekend. Periods will subside from

around 12 seconds after Thursday. Rip current risk is high on

most northern beaches. Wave penetration in normally quiet passages

has been better than models have forecast and even the Vieques

buoy has been running 8-9 feet. Had to make some manual adjustment

in the grids there. Have extended Rip Current risk and high surf

out through 8 AM AST Friday morning to better reflect the

longevity of this event.

Coastal Flooding is likely with strong onshore flow and tides that

will peak at around 1.8 feet most everywhere before 8:30 AM today.

Although a secondary high tide will occur this evening it is only

about half as high. But, another similar high tide will occur

Thursday and Friday, with some threat of minor coastal flooding

on northern shores each of these mornings.

&&

.PRELIMINARY POINT TEMPS/POPS...

SJU 81 74 82 75 / 50 20 20 20

STT 84 74 85 75 / 50 20 20 20

cycloneye
Category 5

Posts: 2,507

Puerto Rico Weather Jan 12, 2017 4:24:40 GMT -6

Quote

Post by cycloneye on Jan 12, 2017 4:24:40 GMT -6

Area Forecast Discussion

National Weather Service San Juan PR

517 AM AST Thu Jan 12 2017

.SYNOPSIS...High pressure in the western Atlantic has driven a

cold front south of the area. Strong winds will persist into next

week with isolated to scattered showers throughout the period over

smaller islands and the mountains and windward plains of Puerto

Rico.

At upper levels...A weak ridge over the area will retrograde into

the central Caribbean by Saturday. A weak trough will pass through

on Monday with flow turning almost due north by mid week next

week.

At mid levels...A trough will extend into the eastern Caribbean on

Saturday from a dissipating cut-off low now northeast of the area

and continue through mid-week next week. High pressure just north

of Cuba will drop southward next week into the western Atlantic.

Except for a few patches of modest moisture Tuesday through

Thursday of next week, mid-level moisture will be nearly absent.

At lower levels...High pressure has driven a cold front through

the area and it is now over the open Caribbean. High pressure will

dominate the weather pattern through the end of next week. Low

pressure about 750 miles northeast of the area will sink south

through Saturday tightening gradients and keeping northeast winds

over the area strong. Patches of shallow moisture will move

through the area on strong winds this week and next week bringing

shallow, isolated to scattered showers with the best amounts over

interior Puerto Rico. Flooding should not be expected.

&&

.DISCUSSION...NWS doppler radar showed many small showers moving

south southwest at about 20 knots over much of the surrounding

waters and well into interior Puerto Rico. A few showers were also moving

around the U.S. Virgin Islands.

Models are showing a gradual increase in the 850 mb winds from

around 20 knots to as much as 32 knots on Friday night. This also

corresponds with an increase in the surface flow forecast. Winds

then continue at slightly reduced, but relatively strong

intensities, through Tuesday. Moisture values reached a 7-day

minimum this morning and will increase through Friday, although

precipitable water will remain under 1.5 inches for at least the

next 7 to 10 days. With similar but limited values of moisture--

mainly confined to the lowest 8000 feet of the atmosphere--showers

will be widely scattered, shallow, small in size and very brief,

with only a few hours of drier air to shut them down from time to

time. Two of those drier periods appear to occur Sunday night and

Tuesday morning, but models cannot be trusted to perfectly predict

something so ephemeral and we will not be able to trust the

timing here. The showers will yield the most over the interior

sections of Puerto Rico due to orographic forcing just as occurred

Tuesday and Wednesday, but all amounts will be light.

&&

.AVIATION...Mainly VFR expected across the local terminals with VCSH

occurring in quick passing SHRA. SFC winds will be mainly from the E

to NE at about 100-20 KT with even higher gusts. TJBQ and TJMZ may

be on the higher end of the range with winds around 20KT and gusting

to 30KT, TJPS in the lower end with winds close to 10KT and gusting

to about 15KT, the rest of the terminals will fall somewhere in

between.

&&

.MARINE...Winds and seas will increase through Friday night in our

northern waters. High tides will be in the mornings between 9 and

11 am each day through Saturday. These periods will be the time

when minor coastal flooding is likely to occur and would expect

that flooding to be the worst on Friday or Saturday mornings. For

this reason will not extend the coastal flood advisory beyond this

afternoon at 2 PM, but it may be re-issued for Friday morning.

High risk of rip currents and high surf are givens with seas

already at or above 10 feet in many Atlantic waters and passages.

Although conditions should begin to improve Saturday and Saturday

night, hazardous conditions, including small craft advisories, are

expected to continue well into the following week. For those

contemplating entering the waters, these are the most dangerous

conditions that have been seen in many months. It is best to

avoid the water or visit our sheltered beaches on the south side

of the island.

&&

.PRELIMINARY POINT TEMPS/POPS...

SJU 82 75 83 74 / 30 50 50 50

STT 85 75 86 72 / 10 40 30 40

cycloneye
Category 5

Posts: 2,507

Puerto Rico Weather Jan 13, 2017 4:20:34 GMT -6

Quote

Post by cycloneye on Jan 13, 2017 4:20:34 GMT -6

Area Forecast Discussion

National Weather Service San Juan PR

514 AM AST Fri Jan 13 2017

.SYNOPSIS...Shallow moist air will continue to move across the

forecast area through at least the next 5 days bringing isolated

to scattered showers...mainly to windward plains and slopes of the

local islands. Fresh to strong northeast flow will turn more

easterly early next week.

At upper levels...Very weak high pressure will approach the area

through Sunday morning as a jet intensifies up to 100 knots

overhead. A weak trough moves through on Monday.

At mid levels...A cut-off low northeast of the Leeward Islands

weakens into a trough that extends into the northeast Caribbean

through Tuesday. As it weakens high pressure builds over the

western Caribbean and continues into the week after next. Mid

level moisture is absent except Monday through Wednesday when

limited amounts are present.

At lower levels... High pressure will continue across the western

Atlantic through the end of next week. It does weaken somewhat

during the latter half of next week. Low pressure about 800 miles

east northeast of Fajardo, Puerto Rico will fade into a trough in

the eastern tropical Atlantic over the weekend.

&&

.DISCUSSION...Numerous small showers have moved onshore in Puerto

Rico and the northern U.S. Virgin Islands with very slight

accumulations. These will continue as a band of moisture moves

into the area, spun off from the low pressure northeast of the

area that has been elongating along a northeast southwest axis

through Culebra. The best accumulations will likely be less than

one quarter inch today and will be concentrated over the mountain

interior of Puerto Rico. Shallow moisture will continue through

next week, and bands of drier air forecast by the GFS are not as

prominent during the next 5 days as they had been in prior

forecasts. So, isolated to scattered showers will continue with

periods of sun.

Winds are expected to increase through early tonight with 15 to 25

mph and gusts up to at least 30 over local waters and exposed

coastal areas of the islands. Winds slowly abate Sunday through

the end of next week as they turn more easterly early next week.

&&

.AVIATION...Showers embedded in the northeasterly trades will

continue to induce brief periods of SHRA over the Leeward, USVI and

TJSJ taf sites until at least 13/16Z. Mostly VFR conditions are

expected across the rest of the local flying area with only VCSH.

After 13/17Z some SHRA are possible across TJMZ and TJBQ. Low level

winds will continue mainly northeast at 15 to 20 kts with higher

gusts.

&&

.MARINE...Winds and seas are still forecast to peak early tonight

and then subside only slowly into next week. Small craft advisory

conditions will continue in most waters exposed to northeast swell

through mid week next week. Expect coastal flooding to peak this

morning but continue longer as seas increase during the day.

Coastal flooding is likely to return Saturday morning when tides

return to nearly the same levels as the last several days. High

surf will increase through the day and breaking waves will

approach 18 feet along many northern coasts by early tonight. As

it was said yesterday, it will be best to keep a safe distance

from the ocean today and tomorrow on the northern, northwestern

and northeastern coasts. Southern coasts will be much more

tranquil in Puerto Rico.

&&

.PRELIMINARY POINT TEMPS/POPS...

SJU 83 76 83 75 / 50 50 60 60

STT 84 75 84 74 / 30 40 40 30

cycloneye
Category 5

Posts: 2,507

Puerto Rico Weather Jan 14, 2017 4:23:02 GMT -6

Quote

Post by cycloneye on Jan 14, 2017 4:23:02 GMT -6

Area Forecast Discussion

National Weather Service San Juan PR

613 AM AST Sat Jan 14 2017

.SYNOPSIS...

A fresh to strong northeasterly wind flow will continue to bring

patches of low level moisture, with clouds and passing showers

across the forecast region during the weekend. Most of the shower

activity is expected to focus across the U.S. Virgin Islands and

to the North of the Cordillera Central. An upper level trough is

forecast to move across the region by early next week.

&&

.DISCUSSION...

Showers embedded in the northeasterly wind flow prevailed

overnight across the local waters, the U.S. Virgin Islands and

to the north of the Cordillera Central of Puerto Rico. This

activity moved fast enough to produce less than half an inch.

However, periods of moderate to heavy rains were detected with the

Doppler Radar.

Under the fresh to strong northeasterly wind flow continue to

expect passing showers and pleasant temperatures across the

islands. This pattern is expected during the next few days, with

patches of low level moisture bringing periods of clouds and

showers over the islands. But, temperatures will begin to warm

slightly and be near normal for January. Model guidance are

indicating the arrival of an upper level trough across the region

by early next week.

&&

.AVIATION...

Mainly VFR conditions are expected to prevail across all

TAF sites through at least 15/02Z. But, many fine showers moving

across the area from the northeast at 25 to 30 knots. Sfc winds 8 to

18 kt with higher gusts. Maximum winds expected 260/85 at

FL410 at 15/00Z.

&&

.MARINE...

Hazardous marine conditions continue across the Atlantic waters

and Caribbean Passages. As a result small craft, high surf and

coastal flood advisories continue in effect for various coastlines

of Puerto Rico and the U.S. Virgin Islands. Hazardous seas are

expected at least until early next week. Seas up to 12 feet with

occasional seas up to 15 feet are expected across most of the

local waters. Seas up to 6 feet are expected across the Caribbean

Coastal waters of Southern Puerto Rico. Beachgoers are urged to

avoid the northern beaches of the islands through at least early

next week. Please refer to the marine products for additional

information.

&&

&&

.PRELIMINARY POINT TEMPS/POPS...

SJU 83 75 84 75 / 40 40 40 40

STT 84 73 85 75 / 30 30 30 40

cycloneye
Category 5

Posts: 2,507

Puerto Rico Weather Jan 15, 2017 4:14:39 GMT -6

Quote

Post by cycloneye on Jan 15, 2017 4:14:39 GMT -6

Area Forecast Discussion

National Weather Service San Juan PR

552 AM AST Sun Jan 15 2017

.SYNOPSIS...Broad surface high will continue to dominate the local

weather pattern for the next several days. A weak area of low

pressure will move quickly across the Atlantic as the surface high

continues to build having little to no impact on the local weather

conditions. Another surface low and associated frontal boundary is

forecast to reach the local area by the end of next week. Short

wave trof will continue through Tuesday as mid to upper level

ridge builds from the west.

&&

.DISCUSSION...Partly cloudy skies were observed across the islands

as trade wind showers on a brisk northeasterly flow moved from

time to time over portions of the U.S. Virgin Islands and the

northern half of Puerto Rico. Rainfall amounts were generally

less than a quarter of an inch. For today, forecast soundings are

indicating PWAT values under 1 inch as a dry mid level air mass

filters across the region from 12z-00z. Therefore, mostly sunny

skies with a few clouds can be expected today across the region.

As the strong surface high continues to build across the western

Atlantic and into the local area...breezy condtions and seasonable

temperatures will continue for the next several days. Short wave

trof aloft is not expected to have a significant impact on the

trade wind cap. However, strong northeasterly wind flow will

continue to bring patches of low level clouds and brief showers at

times across the islands.

&&

.AVIATION...Shallow moist flow from NE at 15 to 25 kt will cont at

LLVLS thru 16/12z carrying small SHRA that will come into the VCNTY

of all TAF sites except TJPS. Nevertheless mostly VFR conditions

will prevail across all TAF sites except for areas of mtn

obscurations til 15/18z. Sfc winds 8 to 15 kt with gusts to 25 kt

psbl in SHRA. Maximum winds will be at FL400 270/90 kt at 15/06Z.

&&

.MARINE...Hazardous marine conditions will continue through at

least Wednesday as northeasterly swell and wind driven seas

slowly subsides across the Atlantic waters and passages. Life

threatening rip currents due to large breaking waves continues

across the northern beaches of the islands. Seas will continue

today between 8-10 feet and northeasterly winds around 20 knots

are also expected to continue across most of the waters.

&&

.PRELIMINARY POINT TEMPS/POPS...

SJU 84 75 84 75 / 20 30 40 40

STT 83 75 83 75 / 20 40 40 30

cycloneye
Category 5

Posts: 2,507

Puerto Rico Weather Jan 16, 2017 4:13:40 GMT -6

Quote

Post by cycloneye on Jan 16, 2017 4:13:40 GMT -6

Area Forecast Discussion

National Weather Service San Juan PR

555 AM AST Mon Jan 16 2017

.SYNOPSIS...High pressure across the western Atlantic will

maintain a fresh northeast wind flow across the local region

through Wednesday. High pressure will weaken at the end of the

week as a deep surface low pressure moves across the western

Atlantic.

&&

.DISCUSSION...Passing showers were observed across the local area

overnight. Most shower activity was observed across the Caribbean

coastal waters. Local area continue to be dominated by a surface

high pressure system which is located across the western Atlantic.

This high pressure system will continue to produce fresh northeast

winds across the local area through at least Wednesday. Therefore,

passing showers will continue to affect the local area from time

to time.

By the later part of the work week, the aformentioned high

pressure system is expected to weaken, which will allow for a

relax in the pressure gradient. As a result, winds will diminish

considerably by Friday. Under a mid to upper level ridge,

relatively fair weather conditions are expected without any

significant weather events affecting the region. Temperatures will

remain very pleasant, with minimum temperatures expected to drop

to the mid to upper 50s by the later part of the work week, as

clear skies are anticipated and winds will be light and variable.

&&

.AVIATION...Mostly VFR conditions expected through the forecast

period. Some passing showers are expected over TIST and TJSJ from

time to time. Low level winds will continue mainly ENE at 10 to 15

kts with higher gusts, mainly in showers.

&&

.MARINE...Latest buoy observations are showing seas between 5 to 7

feet with occasional seas up to 8 feet mainly across the offshore

Atlantic waters. Seas are expected to diminish gradually next few

days. However, marine conditions will continue hazardous through

at least Wednesday. High Surf advisory was cancelled as breaking

waves of 10 feet are no longer expected. Small Craft advisories

will continue in effect through at least Wednesday.

&&

.PRELIMINARY POINT TEMPS/POPS...

SJU 82 74 82 73 / 40 30 30 20

STT 84 72 83 71 / 40 30 30 20

&&

cycloneye
Category 5

Posts: 2,507

Puerto Rico Weather Jan 17, 2017 3:56:45 GMT -6

Quote

Post by cycloneye on Jan 17, 2017 3:56:45 GMT -6

Area Forecast Discussion

National Weather Service San Juan PR

520 AM AST Tue Jan 17 2017

.SYNOPSIS...High pressure across the western Atlantic will move

east as a intense low pressure system exits the U.S. east coast

Wednesday into Thursday. A east to east northeast wind flow will

continue to dominates the local region. Winds will diminish

considerably next few days.

&&

.DISCUSSION...Periods of passing showers prevailed across the

local islands overnight. Showers affected the eastern half of

Puerto Rico with rainfall accumulation less than half inch. An

east to east northeast wind flow will continue to prevail today.

These winds will transport showers across the region from time to

time. Local area will continue to be dominated by a high pressure

system which is located north of the area over the western

Atlantic. This high pressure is expected to weaken next couple of

days as a deep surface low pressure area moves across the western

Atlantic, eroding the high pressure. As a result, winds are

expected to diminish significantly especially after Thursday. No

major changes in the weather pattern is expected next several days

as relatively dry weather conditions are expected to continue

across the local area.

&&

.AVIATION...Mostly VFR conditions are expected across the local

flying area however, a few passing -SHRA/SHRA expected across TAF

sites at times. Winds expected from the E/NE at around 10 kt

increasing at 15 to 20 kt and gusty aft 17/12z.

&&

.MARINE...Seas will continue to gradually subside later today into

Wednesday. Seas up to 7 feet and winds up to 20 knots are expected

to continue through Wednesday morning.

&&

.PRELIMINARY POINT TEMPS/POPS...

SJU 82 73 81 71 / 30 30 30 10

STT 84 72 82 70 / 30 30 20 20

cycloneye
Category 5

Posts: 2,507

Puerto Rico Weather Jan 18, 2017 4:24:45 GMT -6

Quote

Post by cycloneye on Jan 18, 2017 4:24:45 GMT -6

Area Forecast Discussion

National Weather Service San Juan PR

602 AM AST Wed Jan 18 2017

.SYNOPSIS...

A trough aloft will continue its move across the region. A surface

low pressure exiting the eastern U.S. will continue to weaken a

surface high pressure across the southwestern Atlantic. This

pressure systems will induce a moderate east northeast wind flow

across the local islands and surrounding waters, which in turn

will push patches of low level moisture with embedded clouds and

showers across the U.S. Virgin Islands and the northern and

eastern sections of Puerto Rico at times.

&&

.DISCUSSION...

As a surge of moisture moved over the region overnight. This

surge produced scattered showers, but due to their rapid movement

the rainfall totals were minimals. Then, satellite imagery

indicated the intrusion of dry air across the region, producing a

diminish in shower activity across the islands of Puerto Rico and

the U.S. Virgin Islands early this morning. For the rest of this

morning and under the prevailing northeasterly wind, isolated

passing showers can not be ruled out across the windward sections

of PR and the USVI.

A surface low pressure is forecast to move across the western

Atlantic by Thursday. The pressure gradient is forecast to relax

as this low system move eastward across the Atlantic waters.

Also, as mentioned in the previous discussion, winds speed are

expected to diminish considerable becoming more from the east late

in the week and during the upcoming weekend. As this happens, a

frontal boundary is expected to move close to the local islands.

The proximity of this frontal boundary combined with a dry cool

air mass could result in cooler pleasant temperatures by the end

of the week and into the weekend.

&&

.AVIATION...

Mainly VFR conditions are expected to prevail across all

TAF sites through at least 18/22z. Some passing showers are expected

to affect TIST, TISX, TJSJ and TJBQ terminals from time to time. Low

level winds will be mainly northeast at 10 to 15 kts with higher

gusts.

&&

.MARINE...

Marine conditions are expected to slowly improve across the

region today. Mariners can expect seas up to 6 feet and winds

around 18 knots mainly across the Atlantic waters and the

Caribbean Passages. High risk of rip currents are in effect until

this afternoon.

&&

.PRELIMINARY POINT TEMPS/POPS...

SJU 80 69 82 71 / 40 0 20 10

STT 80 72 79 71 / 40 20 20 20

cycloneye
Category 5

Posts: 2,507

Puerto Rico Weather Jan 19, 2017 4:24:10 GMT -6

Quote

Post by cycloneye on Jan 19, 2017 4:24:10 GMT -6

Area Forecast Discussion

National Weather Service San Juan PR

600 AM AST Thu Jan 19 2017

.SYNOPSIS...

A mid to upper level ridge is building over the region. At the

surface, a low pressure centered over the Central Atlantic

continues to weaken a surface high pressure across the

southwestern Atlantic. As a result, winds are expected to continue

calm to light and variable. Mostly clear skies with pleasant and

cool temperatures were registered across the islands overnight.

&&

.DISCUSSION...

Satellite imagery detected a dry air mass filtering across the

region overnight, this air mass limited cloudiness and shower

activity across the islands of Puerto Rico and the U.S. Virgin

Islands. Weather stations across the islands registered coastal

minimum temperatures between low and mid 60s and across the

mountains and valleys in the low 50s.

In general, fair weather conditions with mostly sunny skies and

no shower activity is expected today. As the surface low pressure

moves across the western Atlantic the pressure gradient is

forecast to relax. Winds are expected to diminish considerable

becoming calm to light and variable through the upcoming weekend.

By the weekend, a frontal boundary is expected to move close to

the local islands. As a result, pleasant minimum temperatures are

expected to continue during this period.

&&

.AVIATION...

Mainly VFR conditions are expected to continue across all

terminals through the forecast period. Limited shower activity is

forecast across the local waters. Low level winds will continue

from the ENE at 10-15 kts with lighter land breezes after 19/00z.

&&

.MARINE...

Marine conditions will continue to improve the rest of the week.

Mariners can expect seas between 2 and 5 feet across the coastal

waters and winds around 10 knots. For the beach goers, there is a

moderate risk of rip current across the local beaches.

&&

.PRELIMINARY POINT TEMPS/POPS...

SJU 81 69 83 71 / 10 10 20 40

STT 80 70 79 71 / 10 20 20 20

cycloneye
Category 5

Posts: 2,507

Puerto Rico Weather Jan 20, 2017 4:13:00 GMT -6

Quote

Post by cycloneye on Jan 20, 2017 4:13:00 GMT -6

Area Forecast Discussion

National Weather Service San Juan PR

445 AM AST Fri Jan 20 2017

.SYNOPSIS...

Mid to upper level trough will shift further east of the region

today through Saturday as an upper level high pressure ridge is

expected to build over the western Atlantic then spread across

the region by Sunday and Monday. In the meantime weak a mid level

perturbation is to move just north of the region today and Saturday.

Surface high pressure over the western Atlantic and an area of

Low pressure across the north central Atlantic will create a very

light north to northeast trade wind flow across the region today

through Saturday. The remnants of a cold front is forecast to slowly

sink southwards across the local Atlantic waters Saturday through

Sunday. A high pressure ridge will then spread across the west and

southwest Atlantic. Local winds are to then become more southerly

by Sunday and Monday as this high pressure ridge will sink farther

south across the northeastern caribbean.

&&

.DISCUSSION...Mostly clear skies and little or no shower activity

was observed of reported over land area. light to moderate showers

were noted across the offshore waters and just northwest of PR.

these showers were slowly rifting southwards across the coastal

waters. Winds were light and variable to calm in most areas. Early

morning low temperatures were in mid 60s to near 70 degrees along

coastal areas and between 55-60 degrees in higher elevations and

valleys.

Mostly fair skies and pleasant seasonal weather conditions can be

expected today across most of the region. A few light showers may

form across parts of the islands but activity if any will be of

short duration.

For the weekend and into early next week, patches of low level

moisture along a weakening cold front/frontal boundary move across

the region and aid in the development of some showers across the

northern half and parts of the interior sections of Puerto rico

especially during the early morning and afternoon hours. Lesser

shower activity is expected across the remainder of the islands.

No significant rainfall or accumulations is expected through the

weekend. The low level easterly winds are to become more southerly

by late Sunday and into early next week resulting in slightly

warmer temperatures to the region.

&&

.AVIATION...VFR conditions will continue across the local terminals

during the next 24 hours as fair weather is expected to prevail.

Calm to Light and VRB winds expected through 20/13Z...becoming light

and northerly thereafter with sea breeze variations. No significant

weather hazard expected.

&&

.MARINE...Marine conds will continue to improve today and into the

upcoming weekend as Seas will slowly subside to between 1-4 feet

nearshore and 3-5 feet offshore and local passages. A gentle

north to northeast wind flow will prevail today, becoming more

southerly by late Sunday and continuing into early next week.

There are hazardous impacts for the coastal waters today.

&&

.PRELIMINARY POINT TEMPS/POPS...

SJU 81 72 82 71 / 0 30 30 40

STT 80 70 82 70 / 0 30 30 40

cycloneye
Category 5

Posts: 2,507

Puerto Rico Weather Jan 21, 2017 4:25:38 GMT -6

Quote

Post by cycloneye on Jan 21, 2017 4:25:38 GMT -6

Area Forecast Discussion...CORRECTED

National Weather Service San Juan PR

540 AM AST Sat Jan 21 2017

.SYNOPSIS...A seasonable weather pattern will continue to prevail

across Puerto Rico and the U.S. Virgin Islands through at least

early next week with a few light passing showers possible. A mid

to upper level ridge will build across the northeast Caribbean as

a short wave trough continues to move east southeast and away from

the forecast area today. The ridge aloft will hold through early

next week.

&&

.DISCUSSION...A mid to upper level ridge will continue to build

across the forecast area as a short wave trough moves east southeast

and away from the northeast Caribbean today. The ridge aloft will

hold through early next week, resulting in a seasonable weather

pattern today through Monday. At lower levels, a high pressure

north of the area will continue to promote a gentle north to

northeast wind flow. Surface winds are expected to become southerly

on Monday as the surface high pressure moves into the central

Atlantic and a frontal boundary approaches from the west. The

frontal boundary and associated mid to upper level trough will

erode the ridge pattern to result in moisture advection from the

east southeast. This will increase the chance of rainfall late

Monday-early Wed.

A drier weather pattern will prevail Thu and into the upcoming

weekend as a mid level ridge builds across the area and a

surface high establishes across the west and central Atlantic.

&&

.AVIATION...VFR conditions will continue across the local

terminals during the next 24 hours as fair weather is expected

to prevail. Calm to Light and VRB winds expected through

21/13Z...becoming light and northerly thereafter with sea breeze

variations. No significant weather hazard expected.

&&

.MARINE...Seas are expected to build early next week but remaining

below the Small Craft Advisory criteria. There is a moderate risk

of rip currents along the Atlantic shoreline of Puerto Rico,

Culebra and St Thomas.

&&

.PRELIMINARY POINT TEMPS/POPS...

SJU 82 73 82 74 / 30 30 30 20

STT 83 70 83 73 / 30 30 30 20

cycloneye
Category 5

Posts: 2,507

Puerto Rico Weather Jan 22, 2017 4:34:34 GMT -6

Quote

Post by cycloneye on Jan 22, 2017 4:34:34 GMT -6

Area Forecast Discussion

National Weather Service San Juan PR

530 AM AST Sun Jan 22 2017

.SYNOPSIS...A mid level ridge will prevail through much of the

forecast period, with a brief weakening expected on Tuesday as

a mid to upper level trough moves north of the area. The mid to

upper level trough and associated surface boundary will result in

moisture advection Tuesday-early Wednesday. Therefore, continue

to expect a seasonable weather pattern across Puerto Rico and the

U.S. Virgin Islands with an increase in passing showers on Tuesday.

&&

.DISCUSSION...As the mid level ridge holds across the forecast

area, a generally fair and mainly stable weather pattern will

continue to prevail with a few passing showers possible across

windward areas. The ridge will briefly erode as a broad mid to

upper level trough moves north of the area. The aforementioned

mid to upper level trough and associated surface boundary will

result in moisture advection Tuesday and possibly Wednesday.

However, the bulk of moisture is expected to remain over waters

and east of the forecast area. At lower levels, a high pressure

north of the area will continue to promote a gentle east northeast

wind flow today. Surface winds are expected to become southerly on

Monday as the surface high pressure moves into the central

Atlantic and the boundary approaches from the west. Therefore,

continue to expect a seasonable weather pattern across Puerto Rico

and the U.S. Virgin Islands with limited shower activity through

the forecast period. The chance of passing showers will slightly

increase on Tuesday. Temperatures may increase Monday and Tuesday

under the southerly wind flow.

&&

.AVIATION...VFR conds will prevail thru the forecast period.

SCT SHRA expected across central/western PR after 22/16Z which

could cause VCSH at TJBQ, TJPS, and TJMZ. SCT SHRA also expected

over the waters and near TISX after 22/16Z. Winds from the ENE at

5- 10 KT with sea breeze variations today.

&&

.MARINE...Seas will remain to 3-5 feet today. However...a northwest

swell will reach the local waters...with seas building to 4-6

feet by midweek. There is a high risk of rip currents along the

Atlantic shorelines of Puerto Rico. The high risk of rip currents

will continue to prevail during the next few days.

&&

.PRELIMINARY POINT TEMPS/POPS...

SJU 83 73 85 74 / 20 20 30 20

STT 83 72 84 75 / 20 40 40 40

cycloneye
Category 5

Posts: 2,507

Puerto Rico Weather Jan 23, 2017 4:17:36 GMT -6

Quote

Post by cycloneye on Jan 23, 2017 4:17:36 GMT -6

Area Forecast Discussion

National Weather Service San Juan PR

442 AM AST Mon Jan 23 2017

.SYNOPSIS...Weak surface high across the central Atlantic and a

surface low across the western Atlantic will promote a light to

moderate southerly wind flow today and Tuesday. Relatively dry

air expected today with an increase in moisture on Tuesday, mainly

for the USVI. Upper ridge to move in today, keeping a stable

atmosphere. Slightly warmer daytime temps expected today across

the San Juan area due to dry air and southerly winds.

&&

.DISCUSSION...Fair weather prevailed overnight across the local

area with a light and variable wind and variably cloudy skies.

Overnight temperatures dipped into the mid 60s to lower 70s

across the lower elevations and into the upper 50s to low 60s

across the higher elevations. For today, the local pattern is

expected to present a change when we compare to what we have been

observing the past several days. Southerly winds are expected

today which will cause rather warm temperatures across the San

Juan metro area, portions of northeastern PR, and the north

central sections of PR with max daytime temps into the upper 80s

possible, the rest of the local area should remain with temps in

the low to mid 80s. Very little shower activity is expected today

since the airmass is relatively dry, however there is some limited

moisture in the lower levels and the combination of the limited

moisture with the daytime heating and the sea breeze convergence

will give us a chance of rain across the NW quadrant of PR this

afternoon with only a slight chance of showers elsewhere.

Higher moisture is expected to move in on Tuesday but mainly for

the USVI as the SFC low across the western Atlantic moves

northeast. This will increase the chances of showers for the USVI, also

cause winds to shift direction from southerly to westerly late

Tuesday night into Wednesday morning then to northerly winds on

Wednesday afternoon. Even with this rather rare wind shift for our

area, the chance of rain remains mainly for the northern half of

PR, the USVI and the Atlantic waters, meaning that there is no

real significant change in the areas with higher chances of rain

in the early morning hours of Wednesday and on Wednesday

afternoon.

For the latter part of the week, the light to moderate winds will

be from the NE on Thursday and mainly easterly by Friday.

Relatively dry airmass to prevail on those days as well so the

shower activity is expected to be minimal.

&&

.AVIATION...VFR conds will prevail thru the forecast period. Shower

development will remain possible across NW PR after 23/16Z which may

result in VCSH at TJBQ. Shower activity expected to increase across

the Leeward terminals aft 24/00z. Light southerly winds with sea

breeze variations are expected today.

&&

.MARINE...A moderate northerly swell will continue affecting the

local Atlantic waters and Caribbean passages over the next few

days. Seas will build to 4-6 feet by midweek as a northwest swell

reaches the regional waters. At this time, the local buoys are

reporting seas of 3 to 4 feet across the nearshore waters and an

estimated 4 to 5 feet across the local Atlantic offshore waters.

Having said that, the local breaking waves across northern and

northwestern PR could be between 5 and 7 feet, which will cause a

high risk of rip currents across many of the Atlantic facing

beaches of Puerto Rico. There is a moderate risk of rip currents

for many of the remaining beaches in PR, Vieques, Culebra, and the

USVI.

&&

.PRELIMINARY POINT TEMPS/POPS...

SJU 86 73 90 75 / 10 0 30 30

STT 81 74 82 75 / 20 20 30 30

cycloneye
Category 5

Posts: 2,507

Puerto Rico Weather Jan 24, 2017 4:04:40 GMT -6

Quote

Post by cycloneye on Jan 24, 2017 4:04:40 GMT -6

Area Forecast Discussion

National Weather Service San Juan PR

434 AM AST Tue Jan 24 2017

.SYNOPSIS...Surface low across the western Atlantic will promote

a light to moderate southerly wind flow today, then a surface high

moves in just north of the local islands, shifting winds to a

northerly direction on Wednesday. Relatively dry air expected

today with an increase in moisture mainly for the USVI. Upper

trough developing to our west by Wednesday. Slightly warmer than

normal daytime temps expected today across the San Juan area and

other portions of the northern half of PR due to dry air and

southerly winds.

&&

.DISCUSSION...Fair weather prevailed overnight across the local

area with a light and variable wind and variably cloudy skies.

Overnight temperatures dipped into the mid 60s to lower 70s

across the lower elevations and around 60 to the mid 60s across

the higher elevations. For today, we can expect southerly winds

once again and therefore warmer than normal temperatures for

portions of the northern coastal municipalities of PR including

the San Juan Metro Area, where temperatures are expected to reach

the upper 80s today. The rest of the local area should remain with

temps in the low to mid 80s. Very little shower activity is

expected today since the airmass is relatively dry, however there

is some moisture moving in from the south but it appears that it

will stay over the USVI briefly then move away. This may cause

isolated showers in the afternoon and then scattered showers

tonight around the local waters and particularly just to the east

of the USVI.

Surface low across the western Atlantic is causing the southerly

wind flow today, then there is a SFC high that will move over the

Bahamas on Wednesday. This will cause winds to shift direction

from southerly to westerly late tonight into Wednesday morning

then to northerly winds on Wednesday afternoon. This rare wind

shift for our area will also bring a patch of moisture on

Wednesday, which means that scattered showers are expected across

the local waters tonight into Wednesday morning then scattered

showers expected across the northern USVI and the northern half of

PR. However, the accumulations are expected to be modest.

For the latter part of the week, the light to moderate winds will

be from the NE on Thursday and mainly easterly by Friday.

Relatively dry airmass to prevail on those days as well so the

shower activity is expected to be minimal. In fact, predominantly

fair weather, with brief moments of clouds and showers, is

expected into the weekend.

&&

.AVIATION...VFR conditions will continue to prevail across all

terminals through 24/24z. Light southerly or variable winds expected

early this morning, becoming mostly S-SW at 5-10 kts aft 14z.

&&

.MARINE...North northeast swell continue to affect the local

Atlantic waters and passages. Small craft operators should

exercise caution as seas are between 4 to 6 feet and winds up to

20 knots. A slightly stronger northwesterly swell is expected to

invade the local waters by Wednesday night, causing an increase in

seas and possibly meeting small craft advisory criteria. There is

a high risk of rip currents today for the north and northwest

coast of PR and Culebrita beach in Culebra.

&&

.PRELIMINARY POINT TEMPS/POPS...

SJU 89 75 82 72 / 20 20 30 30

STT 83 74 81 72 / 20 20 30 30

cycloneye
Category 5

Posts: 2,507

Puerto Rico Weather Jan 25, 2017 3:48:35 GMT -6

Quote

Post by cycloneye on Jan 25, 2017 3:48:35 GMT -6

Area Forecast Discussion

National Weather Service San Juan PR

543 AM AST Wed Jan 25 2017

.SYNOPSIS...Cold front just northwest of the region will move over

the local islands today. Clouds and scattered showers will affect

the local islands through tonight. Then...high pressure will build

in the wake of the front...bringing a fair weather pattern to the

local region through the end of the week.

&&

.DISCUSSION...Satellite imagery as well as the latest surface

analysis showed a frontal boundary located over the Mona Passage

this morning. This front will move across the local region through

tonight...increasing the cloudiness and shower activity over

Puerto Rico and the U.S. Virgin Islands. No significant rainfall

accumulations are anticipated with this feature...as moisture will

remain near normal levels. As the front crosses the islands, a

moderate northerly flow will establish across the local area.

Surface high pressure and a mid level ridge located over Cuba

will expand northeastward over the Western Atlantic on Thursday.

This will result in drier conditions across the Northeast

Caribbean region Thursday and Friday. The mid level ridge will

maintain a stable atmosphere and rainfall amounts will be limited.

Winds will return to the east on Friday and east-southeast on

Saturday. As the wind shift, warmer temperatures between 85-88

degrees are possible once again from Friday through early next

week. Moisture will likely surge on Sunday as an area of moisture

approaches the region from the east.

&&

.AVIATION...Weak front moving from the Atlantic waters into the

local flying area will create brief periods of -RA/VCSH and tempo

MVFR cigs across the west and northern terminals of PR through the

morning hours. Similar conditions expected to spread across the rest

of the terminals through the afternoon hours. Winds expected to

continue WNW around 10 kts thru 16z...then NNE with sea breeze

variations across southern terminals of PR.

&&

.MARINE...NW swell will bring hazardous seas across the offshore

Atlantic Waters later today. Seas are expected to build to 5-7

feet across the local Atlantic Waters between this afternoon and

Thursday. As a result...a Small Craft Advisory is in effect for

the Offshore Atlantic Waters from this afternoon. Seas across the

coastal waters of Puerto Rico are forecast between 3-5 feet

through the end of the week.

&&

.PRELIMINARY POINT TEMPS/POPS...

SJU 83 74 83 73 / 40 20 10 10

STT 83 73 83 72 / 40 20 10 20

Shoutbox

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Jul 7, 2024 12:12:03 GMT -6

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Puerto Rico Weather

Post by cycloneye on Jan 11, 2017 4:33:35 GMT -6

Post by cycloneye on Jan 12, 2017 4:24:40 GMT -6

Post by cycloneye on Jan 13, 2017 4:20:34 GMT -6

Post by cycloneye on Jan 14, 2017 4:23:02 GMT -6

Post by cycloneye on Jan 15, 2017 4:14:39 GMT -6

Post by cycloneye on Jan 16, 2017 4:13:40 GMT -6

Post by cycloneye on Jan 17, 2017 3:56:45 GMT -6

Post by cycloneye on Jan 18, 2017 4:24:45 GMT -6

Post by cycloneye on Jan 19, 2017 4:24:10 GMT -6

Post by cycloneye on Jan 20, 2017 4:13:00 GMT -6

Post by cycloneye on Jan 21, 2017 4:25:38 GMT -6

Post by cycloneye on Jan 22, 2017 4:34:34 GMT -6

Post by cycloneye on Jan 23, 2017 4:17:36 GMT -6

Post by cycloneye on Jan 24, 2017 4:04:40 GMT -6

Post by cycloneye on Jan 25, 2017 3:48:35 GMT -6

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