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970
FXCA62 TJSJ 100600
AFDSJU

Area Forecast Discussion
National Weather Service San Juan PR
200 AM AST Fri Jul 10 2026

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

.KEY MESSAGES...
Issued at 200 AM AST Fri Jul 10 2026

* Above-normal temperatures will continue, with the greatest heat
  impacts expected early next week.

* Elevated to critical fire weather concerns will continue today
  through the weekend.

* Breezy to windy conditions will persist through early next
  week.

* Moderate to locally high concentrations of Saharan dust will
  peak today before gradually diminishing through the weekend.

* The greatest potential for showers and isolated thunderstorms
  is expected early next week as the next tropical wave moves
  across the region.


&&

.Short Term(Today through Sunday)...
Issued at 200 AM AST Fri Jul 10 2026

The primary weather concerns through the short-term period will be
breezy to windy conditions, hazy skies, above-normal temperatures,
and fire weather concerns. A strong Atlantic surface ridge will
maintain brisk easterly trade winds, transporting a drier-than-
normal air mass and moderate to locally high concentrations of
Saharan dust across the region through Sunday morning.
Precipitable water values will remain below normal, while warming
mid-level temperatures, dry air aloft, and a persistent trade-wind
cap maintain a stable atmosphere. Any available moisture will
remain largely confined below 850 mb, limiting vertical cloud
development and shower activity to isolated passing trade-wind
showers.

By Sunday afternoon and evening, moisture associated with the next
tropical wave will gradually increase across the region, allowing
precipitable water values to recover to near-normal levels.
Meanwhile, an upper-level trough will gradually evolve into a
cutoff low while approaching from the northeast. Although these
features may support a slight increase in shower activity,
organized convection is not anticipated, keeping the flooding and
lightning threats low.

Localized areas of heat may affect sensitive individuals,
particularly across urban, coastal, and lower-elevation areas. In
addition, the combination of gusty winds, low humidity, and
increasingly dry fuels will continue to support elevated fire
weather conditions, especially across southern Puerto Rico. Refer
to the Fire Weather Discussion below for additional details.


&&

.Long Term(Monday through Friday)...
Issued at 200 AM AST Fri Jul 10 2026

As mentioned in previous discussions a tropical wave is forecast to
approach the islands from the east bringing a moister weather
pattern by the beginning of the workweek. The latest model guidance
continues to suggest mid level relative humidity values ranging
between 50 and 75th percentile or near to above normal values for
this time of the year. At the same time, the proximity of an upper-
level low northeast of the forecast area will maintain slightly
cooler mid-level temperatures, around -8 to -9 degrees Celsius at
500 mb, supporting modest instability. With only low concentrations
of Saharan dust expected through much of Monday, scattered showers
and isolated thunderstorms will be possible. The greatest coverage
is expected across the U.S. Virgin Islands and eastern Puerto Rico
during the morning, followed by the interior and western sections of
Puerto Rico during the afternoon. Locally heavy rainfall may result
in ponding of water on roads and in poorly drained areas, with
isolated instances of minor flooding.

Saharan dust model guidance suggests that moderate Saharan dust
concentrations will approach the islands on Tuesday resulting in
hazy skies, periods of reduced visibility, and deteriorating air
quality, particularly for sensitive groups. At the same time, the
tropical wave will move west of the region while a drier and more
stable air mass gradually filters into the area. Precipitable water
values are forecast to decrease to near or slightly below normal
levels by midweek, while mid-level temperatures gradually warm and
relative humidity decreases through the column. As a result, shower
activity should become more limited from Tuesday through Friday,
with brief passing trade-wind showers during the overnight and
morning hours followed by isolated afternoon convection, primarily
over the western interior of Puerto Rico. Although localized ponding
cannot be ruled out, the overall flooding threat should remain low
during the second half of the workweek.

Seasonal to slightly above-normal temperatures are expected through
Friday. Combined with sufficient low-level moisture, heat indices
will likely exceed 100 degrees Fahrenheit across urban and coastal
areas each afternoon, particularly along the northern and southern
coastal plains of Puerto Rico and portions of the U.S. Virgin
Islands. In addition, the presence of Saharan dust may limit
overnight radiational cooling, leading to warmer-than-normal minimum
temperatures. Therefore, the heat risk is expected to remain
elevated throughout much of the workweek despite the gradual drying
trend.


&&

.AVIATION...
(06Z TAFS)
Issued at 200 AM AST Fri Jul 10 2026

VFR conditions will prevail at all TAF sites. HZ will persist due
to moderate to locally high concentrations of Saharan dust. E-ESE
winds at 8-14 kt will increase to 18-22 kt with gusts around 30 kt
between 10/12Z and 10/22Z, diminishing thereafter.


&&

.MARINE...
Issued at 200 AM AST Fri Jul 10 2026

A broad surface high pressure centered over the Atlantic will
continue to support moderate to fresh easterly winds, occasionally
strong, across the regional waters through at least late tonight.
These conditions will maintain choppy to hazardous seas, with wave
heights generally ranging from 5 to 7 feet across the offshore
Atlantic waters, Caribbean waters, and the Mona Passage. Small Craft
Advisories remain in effect for these waters through at least
midnight tonight. Meanwhile, a drier air mass combined with moderate
to high concentrations of Saharan dust will persist through the
weekend, promoting hazy skies and periods of reduced visibility
across the region.


&&

.BEACH FORECAST...
Issued at 200 AM AST Fri Jul 10 2026

Short period wind-driven waves and breezy conditions will promote a
moderate risk of rip currents across most beaches of Puerto Rico and
the U.S. Virgin Islands through next week. A moderate risk means
that life-threatening rip currents are possible in the surf zone.
Beachgoers are urged to exercise caution each day, particularly from
the mid-morning hours through sunset.

Additional beach hazards include the presence of Saharan dust, which
will continue to cause hazy skies, reduced air quality, and warm to
hot conditions during the peak afternoon hours. Sensitive groups
should consider limiting prolonged outdoor exposure due to reduced
air quality associated with Saharan dust, while everyone should stay
hydrated and use caution if spending time under the sun.


&&

.FIRE WEATHER...
Issued at 200 AM AST Fri Jul 10 2026

Persistent rainfall deficits, critically dry fuels, and elevated
KBDI values continue across much of Puerto Rico and the U.S.
Virgin Islands, with the greatest concerns across southern Puerto
Rico, Vieques, Culebra, and St. Croix. A drier-than-normal air
mass, moderate to locally high concentrations of Saharan dust, and
breezy to windy easterly trade winds will continue to support
favorable conditions for wildfire growth and spread through the
weekend. Fire weather concerns will remain elevated to locally
critical as low humidity and gusty winds persist. A Fire Danger
Statement has been issued today, and additional fire weather
products may be needed through the weekend.


&&

.SJU WATCHES/WARNINGS/ADVISORIES...
PR...Fire Danger Statement from 10 AM this morning to 4 PM AST this
     afternoon for PRZ014>016-018-019-022-024-027.

VI...None.

AM...Small Craft Advisory until midnight AST tonight for AMZ711-733-
     741.

     Small Craft Advisory until 6 AM AST early this morning for
     AMZ712-735.

&&

$$

EVE...DSR/MMC
MID...ICP

NWS SJU Office Area Forecast Discussion