558 
FXCA62 TJSJ 072051
AFDSJU

Area Forecast Discussion
National Weather Service San Juan PR
451 PM AST Fri Oct 7 2022

.SYNOPSIS...

Active weather is expected across the islands through at least the 
weekend, and likely into early in the next workweek. This is 
associated with an upper-level trough providing instability over the 
region and an influx in moisture. Typical marine conditions are 
expected for the local waters, with seas of up to 5 feet, and a low 
to moderate risk of rip currents for local beaches.

&&

.SHORT TERM...Tonight through Sunday...

Moisture has moved into the region, with satellite estimated 
precipitable water values of around 1.9 to 2.1 inches. This area of 
moisture is currently over the USVI and northeastern Puerto Rico; 
PWAT values are generally within seasonal normals or higher across 
the islands. Meanwhile, an upper-level trough is approaching from 
the east, providing instability over the area. Enhanced moisture and 
instability will persist through the weekend over the region, which 
will result in enhanced shower and thunderstorm activity. Though 
showers are likely to be relatively quick-moving, there is the 
potential for locally high rainfall totals in areas that see the 
strongest showers/heaviest rainfall and areas that see repeated 
shower activity and training of storms. As such, there is an 
enhanced risk for urban and small stream flooding, and localized 
flash flooding cannot be ruled out.

&&

.LONG TERM...Monday through Saturday...From Prev Discussion...

A surface high pressure located in the central Atlantic is expected 
to dominate for the first half of the long-term period. Nonetheless, 
in our local area, a seasonal weather scenario is forecasted for all 
the islands. By Monday, a tropical wave located east of the Leeward 
Islands is expected to bring showers and isolated thunderstorms. 
Winds are expected to shift from a more southeasterly flow, local 
afternoon convection is likely to be centered over the northwestern 
and western portions of Puerto Rico. The US Virgin Islands can 
expect morning showers across the area and scattered showers during 
the afternoons. This tropical wave will bring additional moisture 
content from the Caribbean that is forecasted to persist until 
Wednesday. From Thursday through Saturday, winds will persist 
with a east-southeast flow and shower activity will be observed 
across the northwestern, western and northern portions of Puerto 
Rico. Although, a slightly drier air mass will filter in to the 
region limiting the activity to the mentioned portions. A frontal 
boundary will move out of the eastern coast of the United States 
and associated moisture could reach the local area by the 
beginning of the following week. Heat index values will remain 
above 100 degrees each day, mostly over urban and coastal areas 
across north-central Puerto Rico. 

&&

.AVIATION...
(18Z TAFS)

VCSH expected across the local terminals for the rest of today. 
VCTS is possible at TJBQ through 07/21Z. Winds will continue from 
the East at 10-15 KT with occasional gusts through 07/22Z, will 
weaken thereafter, while VCSH will remain possible overnight at 
IST, ISX, and JSJ. The local winds will increase once again after 
08/13Z with sea breeze variations developing as well. SHRA/TSRA 
possible once again after 08/17Z, causing VCTS at TJBQ.

&&

.MARINE...

Moderate to fresh winds, with speeds of up to 15 to 20 knots, will 
maintain some choppy conditions across the waters. Still, seas will 
generally remain around 5 feet or less. There is a moderate risk of 
rip currents for nearly all local beaches, though modest improvement 
is expected for tomorrow.

&&

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

$$

SHORT TERM...WS
LONG TERM....CRS
AVIATION...WS
PUBLIC...CVB