264
FXCA62 TJSJ 091900
AFDSJU

Area Forecast Discussion
National Weather Service San Juan PR
300 PM AST Sat May 9 2026

...New SHORT TERM, AVIATION, MARINE, BEACH FORECAST, FIRE WEATHER...

.KEY MESSAGES...
Updated at 300 PM AST Sat May 9 2026

* Up to breezy conditions are forecast to continue through the next
  several days. Unsecured objects could blow around.

* A limited heat risk will continue over many coastal and urban
  areas of the islands. Heat indices above 100 degrees are forecast
  for these areas. This level of heat affects primarily those
  individuals sensitive to heat, especially when outdoors without
  effective cooling and/or adequate hydration.

* Up to a moderate risk or rip currents over the next few days over
  the northern and eastern PR, as well as over Vieques, Culebra and
  St. Croix.

* Afternoon showers are forecast over mainly interior to the western
  half of Puerto Rico, with passing showers moving over the eastern
  region.

* Across the US Virgin Islands, breezy winds may bring a few
  showers at times, but in general, fair and hot conditions are
  expected today.

&&

.Short Term(This evening through Monday)...
Issued at 300 PM AST Sat May 9 2026

A surface high north of the region will promote up to breezy
easterly winds are forecast to continue through the next several
days. Unsecured objects could blow around. Easterly steering flow
will gradually veer overnight to become more east to east-southeast
as the surface high moves eastward. Current satellite derived PWAT
values indicate mostly dry air over most of the region (around an
inch to 1.2 inches). PWAT values slightly above 1.20 inches are
being detected over western PR (due to afternoon convection over the
area) and over St. Croix (a patch of moisture moving from the
Anegada Passage). Steering flow will bring patches of both moisture
and drier air towards the islands, prompting precipitable water
(PWAT) values at below normal to normal values. More broad patches
of moisture will reach the region on Monday. Available moisture will
be shallow however, being mainly below 800 mb tonight and tomorrow
and reaching a bit higher on Monday. This is due to a mid to upper
level ridge across the western Caribbean Sea, maintaining a drier
air above 700 mb, this ridge will move a bit northward to start the
next workweek. With this below normal to normal moisture and
increasing subsidence, inhibited shower activity and rainfall
coverage is forecast. However, passing shower activity will continue
to reach windward sectors of the islands during the morning and
overnight hours while diurnal heating and local effects will still
promote afternoon convection over mainly interior to sectors of
western PR (possibly closer to the coast due to breezy conditions).
This pattern will increase on Monday as the patch of moisture moves
over the region, however breezy conditions will inhibit major
rainfall accumulations. East to east-southeast steering flow will
continue to promote a limited heat risk over many coastal and urban
areas of the islands where heat indices are forecast in the upper
90s to low 100s. This level of heat affects primarily those
individuals sensitive to heat, especially when outdoors without
effective cooling and/or adequate hydration. Under breezy
conditions, increasing temperatures and with patches of drier air
moving over the area, the potential for elevated fire danger
remains, please see fire weather section below and stay tuned for
future updates.

&&

.Long Term(Tuesday through Saturday)...
Issued at 212 AM AST Sat May 9 2026

The long-term outlook will be dominated by drier-than-normal
conditions through the first half of the period, as a mid-level
ridge and atmospheric subsidence prevail across the region. This
pattern will suppress shower formation across Puerto Rico and the
U.S. Virgin Islands through at least Thursday. At the surface, a
high-pressure system over the central Atlantic will maintain
moderate to locally fresh east-southeasterly winds. These winds will
drag patches of moisture and quick-moving showers into windward
areas during the overnight and morning hours, followed by isolated
afternoon convective activity over interior and west-northwestern
Puerto Rico, mainly driven by daytime heating and local effects.
During this period isolated thunderstorms cannot be ruled out, with
limited coverage across these areas. Rising temperatures, combined
with warm and humid low-level conditions, will result in a limited
heat risk each day, possibly increasing by the end of the workweek.
This will primarily affect sensitive individuals or those with
prolonged outdoor exposure and inadequate hydration. By the end of
the period, an increase in moisture is forecast to move into the
area, raising the potential for more widespread showers and
thunderstorms across the region.

&&

.AVIATION...
(18Z TAFS)
Issued at 300 PM AST Sat May 9 2026

Mainly VFR conditions expected to prevail over the next 24 hrs.
-RA expected to develop along W PR after 09/20Z, mostly staying
south of TJBQ. Winds will be from the E at 12-18 kts, gusting up
to 20-25 kts or slightly higher, mostly from 09/14-22Z. Then,
becoming light and variable overnight. VCSH over TIST and TISX are
possible during the overnight period or into early morning and
then across TJSJ. Aft 10/17Z, TJBQ may observe VCSH/-RA.

&&

.MARINE...
Issued at 300 PM AST Sat May 9 2026

A strengthening surface high pressure over the western Atlantic
will promote moderate to locally fresh east-to-northeast winds
across the regional waters the rest of the weekend through at
least Monday night. As a result, choppy marine conditions are
expected with sustained winds of 15 to 20 knots and occasional
higher gusts. Seas will range between 3 and 5 feet, occasionally
reaching up to 6 feet. Small craft are urged to exercise caution
across portions of the local waters.

&&

.BEACH FORECAST...
Issued at 300 PM AST Sat May 9 2026

Tonight, there is a moderate risk of rip currents across the
north, east, and southeast-facing beaches of Puerto Rico, Vieques,
Culebra, and the U.S. Virgin Islands due to breezy winds. This
means life-threatening rip currents are possible in the surf zone,
and beachgoers should exercise caution. A similar pattern is
expected to continue through the rest of the weekend and into next
week. A low risk of rip currents will persist across the southern
and western beaches of Puerto Rico, however, life-threatening rip
currents can still occur near groins, jetties, reefs, and piers.

By the middle of next week, a small long-period northeasterly
swell may arrive and spread across local waters, resulting in
breaking waves of up to 4 to 5 feet, occasionally higher. For
additional information and location-specific rip current details,
visit weather.gov/beach/sju.

&&

.FIRE WEATHER...
Issued at 300 PM AST Sat May 9 2026

Rain-free conditions have prevailed across the southern sections
of Puerto Rico so far today, and a drier air mass over the region
is allowing relative humidity values to drop to critical fire
weather thresholds. The Cabo Rojo and Camp Santiago RAWS stations
have been registering relative humidity values in the upper 40s to
low 50s, along with breezy conditions. Also, KBDI index values
remain elevated, particularly in Cabo Rojo. Therefore, conditions
remain favorable for the spread of wildfires across the southern
coastal plains of Puerto Rico.

Fire partners are encouraged to remain vigilant, as similar
conditions are likely to persist over the coming days. The
issuance of a Fire Danger Statement (RFDSJU) cannot be ruled out.

&&

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

$$

SHORT TERM...MRR
LONG TERM...GRS
AVIATION/MARINE/BEACH/FIRE...YZR

NWS SJU Office Area Forecast Discussion