186
FXCA62 TJSJ 030815
AFDSJU

Area Forecast Discussion
National Weather Service San Juan PR
415 AM AST Sun May 3 2026

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

.KEY MESSAGES...
Updated at 410 AM AST Sun May 3 2026

* A few brief afternoon showers are possible over western Puerto
  Rico today, with mostly fair weather expected overall.

* Increasingly stable conditions will lead to generally fair
  weather into early this week.

* Warmer-than-normal temperatures will persist, with heat indices
  reaching or exceeding 100F across urban and coastal areas.

* A moderate risk of rip currents will continue along north- and
  east-facing beaches of Puerto Rico and the U.S. Virgin Islands.

&&

.Short Term(Today through Tuesday)...
Issued at 410 AM AST Sun May 3 2026

A gradual transition toward a somewhat more stable weather pattern
will continue through the period. PWAT values will fluctuate between
near normal and below normal, generally ranging from about 1.3 to
1.6 inches, while mid-level relative humidity (700-500 mb)
remains limited, around 30 to 45 percent. Although 500 mb
temperatures near -9C to -7C and above normal 700-500 mb lapse
rates indicate sufficient instability aloft, the primary limiting
factor will be the available moisture content, resulting in mostly
shallow convective activity.

For today, expect mostly clear to partly cloudy skies during the
morning hours, followed by isolated to scattered afternoon showers
over the interior and northwestern Puerto Rico, driven by diurnal
heating and sea breeze convergence. Passing trade wind showers will
continue across windward areas and the U.S. Virgin Islands during
the overnight and early morning hours.

On Monday, continued modest drying aloft and PWAT values near to
below normal will promote reduced coverage and intensity of showers,
although isolated afternoon activity will still develop over western
Puerto Rico. Model guidance suggests a modest surge of moisture by
Tuesday morning, which could result in a temporary increase in trade
wind showers, mainly across windward areas. Otherwise, mostly fair
weather conditions will prevail.

Southeasterly wind flow will continue to advect warmer-than-normal
temperatures, supported by above-normal 925 mb temperatures
indicated by model guidance, resulting in highs in the upper 80s to
low 90s and heat indices likely exceeding 100F across coastal and
urban areas.

&&

.Long Term(Wednesday through Sunday)...
Issued at 410 AM AST Sun May 3 2026

An upper level trough will cross the local islands on Wednesday,
causing mid-levels temperature to cool down. Although this would
usually result in an increase in instability, a mid-level ridge will
maintain conditions generally unfavorable for strong showers
production. Later in the workweek, a cold front at the mid-levels
will cross the region. The air mass will dry out further, with the
forecast soundings suggesting considerable dew point depressions and
trade wind caps around 850 mb levels. In general, fair weather will
prevail, but diurnal heating should still trigger localized
convection in the interior and west of Puerto Rico. Also, patches of
moisture trapped in the lower 850 mb of the atmosphere will be
dragged by the trade winds along the Virgin Islands and eastern
Puerto Rico at times. However, the risk of flooding will be low to
none for most of the period.

The steering flow at the surface will be mainly out of the east at
around 10 knots through much of the forecast period. Aloft, winds
will be from the north, but this will not translate into cooler
temperatures. Highs will still reach the upper 80s and low 90s along
many coastal areas, and around 80 in the mountain.

In comparison with the previous cycles, the probability of
precipitation has been decreased for most of the period. By the next
weekend however, the mid level ridge will lose its grip a little, as
a mid to upper level low develops northeast of the Caribbean.
Stronger showers and isolated thunderstorms are expected to form,
mostly focusing along the interior and western Puerto Rico.

&&

.AVIATION...
(06Z TAFS)
Issued at 410 AM AST Sun May 3 2026

VFR conds expected thru the fcst pd. FEW-SCT clouds at or above
FL025-FL030 with limited SHRA activity. Iso VCSH psbl mainly btw
17-22Z across W PR terminals (TJBQ). SFC winds light/vrb ovrngt
bcmg E-SE 10-15 kt aft 13-14Z with sea breeze variations and ocnl
gusts up to 20 kt. The 03/00Z sndg shows winds up to 19 kt blo
FL050. No sig aviation impacts expected.

&&

.MARINE...
Issued at 410 AM AST Sun May 3 2026

A broad high pressure over the central Atlantic will promote gentle
to moderate east to east-southeast winds across most waters through
early this workweek. Moderate to locally fresh winds are expected
across the local Caribbean passages today and tomorrow, where small
craft operators should exercise caution. Seas will range between 3
and 5 feet, occasionally reaching up to 6 feet, due to local wind
waves and a small, long-period northeasterly swell. Passing showers
at times across the waters.

&&

.BEACH FORECAST...
Issued at 410 AM AST Sun May 3 2026

Up to a moderate risk of rip currents (life-threatening rip currents
are possible in the surf zone) will continue today for the north and
east beaches of Puerto Rico, as well as exposed beaches of Culebra
and the USVI. A low risk of rip currents will continue elsewhere.
However, even if the risk for rip currents is low, life-threatening
rip currents often occur in the vicinity of groins, jetties, reefs,
and piers. This pattern will continue at least through Wednesday, as
pulses of a small, long-period northeasterly swell reach the area.
For the second half of the week, the low risk of rip currents
will be more dominant.

For additional information, visit: weather.gov/beach/sju.

&&

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

$$

SHORT TERM/AVIATION...CVB
LONG TERM...ERG
MARINE/BEACH...MRR

NWS SJU Office Area Forecast Discussion