Since 2001 providing the latest information on tropical cyclone activity in the Atlantic Basin and the weather conditions in Puerto Rico.

Local Weather Conditions

 

National Weather Service Today's Weather Impact Levels

National Weather Service Forecast for: San Juan, Puerto Rico  

Updated: 8:23 pm AST Oct 17, 2024

Hazardous Weather Outlook
Tonight

Tonight: Scattered showers, with thunderstorms also possible after midnight.  Mostly cloudy, with a low around 78. Southeast wind around 7 mph.  Chance of precipitation is 50%.
Scattered
Showers
Lo 78 °F
Friday

Friday: Showers likely and possibly a thunderstorm.  Mostly cloudy, with a high near 89. East wind 5 to 13 mph.  Chance of precipitation is 70%. New rainfall amounts between three quarters and one inch possible.
Showers
Likely
Hi 89 °F
Friday
Night
Friday Night: Scattered showers and thunderstorms.  Mostly cloudy, with a low around 78. East southeast wind 5 to 8 mph.  Chance of precipitation is 50%.
Scattered
Showers
Lo 78 °F
Saturday

Saturday: Showers likely and possibly a thunderstorm.  Mostly cloudy, with a high near 91. East wind 5 to 13 mph.  Chance of precipitation is 70%.
Showers
Likely
Hi 91 °F
Saturday
Night
Saturday Night: Scattered showers and thunderstorms.  Mostly cloudy, with a low around 78. East wind around 7 mph.  Chance of precipitation is 50%.
Scattered
Showers
Lo 78 °F
Sunday

Sunday: Showers likely and possibly a thunderstorm.  Mostly cloudy, with a high near 90. East wind 7 to 15 mph, with gusts as high as 20 mph.  Chance of precipitation is 60%.
Showers
Likely
Hi 90 °F
Sunday
Night
Sunday Night: Showers likely.  Cloudy, with a low around 79. East southeast wind 5 to 7 mph.  Chance of precipitation is 70%.
Showers
Likely
Lo 79 °F
Monday

Monday: Showers likely, mainly after noon.  Mostly cloudy, with a high near 91. East southeast wind 7 to 13 mph.  Chance of precipitation is 60%.
Showers
Likely
Hi 91 °F
Monday
Night
Monday Night: Scattered showers.  Mostly cloudy, with a low around 78. East southeast wind 6 to 8 mph.  Chance of precipitation is 40%.
Scattered
Showers
Lo 78 °F

National Weather Service Forecast Details

 

GRLevel3 Radar

  [10/10
GRLevel3 radar from NWS station TJUA

Day 1 rainfall

Day 2 rainfall

Day 3 rainfall

380
FXCA62 TJSJ 172044
AFDSJU

Area Forecast Discussion
National Weather Service San Juan PR
444 PM AST Thu Oct 17 2024


.SYNOPSIS...

Invest 94L, will move north of the islands on Friday and
Saturday, bringing an increase in showers and thunderstorms.
Advancing tropical moisture and the approach of 94L will combine
to bring even more showers and thunderstorms from the weekend into
next week. A northerly swell will arrive late in the weekend and
early next week, causing marine and coastal conditions to
deteriorate.

.SHORT TERM...Tonight through Saturday...

Wet and unstable conditions prevailed today as patches of moisture
passed through the islands. Based on Doppler radar estimates, trade
wind showers left rainfall accumulations around 1-2 inches over the
western and near the Ponce area. Flood advisories were issued for
the western section and the San Juan metropolitan area. A heat
advisory was in effect until 4:00 PM for the urban and low-elevation
areas of the north, west, and southwest through Santa Isabel as heat
indices overpassed 108 degrees Fahrenheit. Occasional shower
activity will continue through tonight. Overnight temperatures will
drop to the upper 70s to low 80s along the urban and low elevations
while upper 60s to low 70s in the higher terrains.

The National Hurricane Center continues monitoring Invest 94L, with
a low chance of cyclone formation of 20% in the next 48 hours and
30% during the next 7 days. The system will approach Puerto Rico and
the US Virgin Islands tomorrow, gradually increasing the potential
for shower and thunderstorm activity through Saturday. Ponding of
water in roadways and poorly drained areas is likely, with urban and
small stream flooding mainly across the east, interior, and west
sections of Puerto Rico.

&&

.LONG TERM...Sunday through Thursday...

PREV DISCUSSION... /issued 718 AM AST Thu Oct 17 2024/

A cold front will dig just north of the Central Caribbean by
Sunday. This system will gradually cause the winds to shift to the
south southeast through Wednesday, carrying moisture from the
Caribbean Sea that will converge over the local islands. As a
result, showers and thunderstorms will increase in frequency, and
could be heavy at times. The risk of flooding will be elevated,
with potential for mudslides in areas of steep terrain, as well as
rapid river rises. The eastern and southern portions of Puerto
Rico, as well as the Virgin Islands are the areas with the highest
probability of precipitation. The days with the best potential
for rain are from Sunday to Tuesday. By Wednesday, conditions will
begin to dry out, but gradually. Moisture will linger at the
surface, so some showers are still anticipated. This break will
not last long, as more moisture is expected to reach the eastern
Caribbean by Thursday and Friday.

It should be noticed that if a dense cloud coverage develops, it
could work to lower the temperatures a little. However, if
sunshine peeks through, the deep-layer south flow will cause it
to feel very muggy and steamy.

&&

.AVIATION...

(18Z TAFS)

Sct SHRA/TSRA to cont thru 17/23Z ovr land and will cont byd 18/14Z
ovr the lcl waters. Lcly obscured mtns and MVFR/IFR conds with
SHRA/TSRA. LLVL winds E 10-15 kt with hir gusts in sea breezes and
arnd TSRA. Max winds NE 30-40 kt btwn FL425-465. TSRA to diminish
aft 17/22Z, but SHRA/isold TSRA to cont across ern PR/USVI and lcl
water byd 18/14Z. Aft 18/14Z areas SHRA/isold TSRA with associated
MVFR/IFR conds and mtn obscurations.

&&

.MARINE...

Surface high pressure over the eastern Atlantic will maintain a
moderate easterly wind flow across the area. Invest 94L located east
of the Leeward Islands will pass just north of the region on Friday.
This will bring squally weather across the local waters from late
tonight trough Friday night, particularly across the Anegada Passage
and the Atlantic waters. By early next week, swells from a low
pressure over the western Atlantic will spread across the Atlantic
waters and passages.

&&

.BEACH FORECAST...

There is a moderate risk of rip currents for northern Puerto
Rico, Culebra, and St. Croix. The risk will stay moderate through
early this weekend, however, it could increase to high as a
long-period northerly swell arrives early next week.

&&

.SJU WATCHES/WARNINGS/ADVISORIES...
PR...None.
VI...None.
AM...None.

&&

$$

SHORT TERM...MNG/MMC
AVIATION...WS
MARINE...MNG/DSR
LONG TERM....ERG

NWS SJU Office Area Forecast Discussion

Saharan Air Layer

Wind Shear Tendency

Sea Surface Temperatures

Sea Surface Temperatures Anomalies

200hPa Velocity Potential Forecast