National Weather Service Today's Weather Impact Levels

069
FXCA62 TJSJ 060856
AFDSJU

Area Forecast Discussion
National Weather Service San Juan PR
456 AM AST Wed May 6 2026

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

.KEY MESSAGES...
Updated at 452 AM AST Wed May 6 2026

* Limited heat risk will persist across urban and coastal areas
  through the end of the workweek, especially for sensitive
  individuals without effective cooling or adequate hydration.

* Moderate rip current risk will continue along northern and eastern
  exposed beaches through Thursday, improve to low risk on Friday,
  and then return to moderate by the weekend as winds increase.

* Mostly fair weather conditions are expected each morning,
  followed by isolated afternoon showers across interior and
  western Puerto Rico.

&&

.Short Term(Today through Friday)...
Issued at 452 AM AST Wed May 6 2026

The primary hazard through the forecast period will continue to be
limited heat risk across urban and coastal areas, primarily
affecting individuals who are extremely sensitive to heat,
especially those outdoors without effective cooling and/or adequate
hydration.

During the overnight hours, generally tranquil weather conditions
prevailed across Puerto Rico and the U.S. Virgin Islands, with
mostly clear to partly cloudy skies and only a few isolated showers
observed over the local waters.

Weather conditions across Puerto Rico and the U.S. Virgin Islands
remained generally quiet on Tuesday, with afternoon convection
failing to develop across most interior and western sections of
Puerto Rico despite modest upper-level dynamical support associated
with a nearby upper-level trough. Although cooler temperatures aloft
and slightly steeper lapse rates promoted marginal instability,
persistent low-level ridging and pronounced dry air within the 850-
600 mb layer continued to limit vertical convective development. As
a result, available low-level lift generated by daytime heating and
sea breeze convergence was insufficient to overcome the stable
layer, suppressing the development of deep afternoon convection.

For today, conditions are expected to remain similar to those
observed yesterday as southeasterly low-level winds continue
transporting patches of shallow moisture across the region from time
to time. Mostly fair weather conditions are expected during the
morning hours, followed by localized afternoon convection developing
across portions of the interior and northwestern quadrant of Puerto
Rico as sea breeze convergence and diurnal heating combine with
local effects. However, convective development will remain
conditional and largely dependent on whether sufficient low-level
moisture and lift can erode the persistent stable and dry layer
aloft. Although some increase in moisture is expected, precipitable
water values will remain generally near to below climatological
normal levels, while lingering 850-600 mb drying will continue
acting as a limiting factor for widespread or sustained
convection. Therefore, any thunderstorms that develop should
remain isolated and relatively brief.

From Thursday into Friday, low-level winds will gradually shift from
easterly to east-northeasterly as surface high pressure strengthens
north of the area, while the upper-level trough continues moving
eastward and ridging aloft becomes more established across the
northeastern Caribbean. This evolving pattern will promote
increasing atmospheric stability through the end of the workweek.
Mostly shallow patches of moisture embedded within the trades will
continue moving across the region from time to time, supporting
isolated passing showers across eastern Puerto Rico and the U.S.
Virgin Islands during the overnight and morning hours, followed by
localized afternoon convection across interior and western Puerto
Rico. Overall moisture content is expected to remain below normal to
near climatological levels. However, limited moisture availability,
persistent mid-level dry air, and weakening lapse rates aloft will
continue limiting vertical convective development. As a result, any
afternoon convection that develops should remain shallow and short-
lived with minimal flooding concerns anticipated.

&&

.Long Term(Saturday through Wednesday)...
Issued at 452 AM AST Wed May 6 2026

A generally drier-than-normal pattern for shower development will
persist through the period as mid-level ridging and subsidence
dominate across the region. Moisture will remain below normal for
this time of year and mostly confined below 700750 mb, limiting
vertical growth and resulting in reduced shower activity. An east to
east-southeasterly steering flow will prevail, supporting a
consistent daily pattern with brief, quick-moving passing showers
affecting windward areas during the overnight and morning hours,
followed by isolated afternoon convection over interior to west-
northwestern Puerto Rico, driven by local effects and mostly diurnal
heating. Isolated thunderstorms cannot be ruled out, but coverage
will remain very limited. Minor traces of Saharan dust may be
present at times, though concentrations are expected to remain low.

Breezy conditions will increase into the weekend and early next
week, particularly across coastal and windward areas, supporting a
limited non-thunderstorm wind risk with occasional gusts up to
around 25 mph or higher at times. Increasing temperatures combined
with warm and humid low-level conditions will promote a limited heat
risk each day, mainly affecting sensitive individuals or those with
prolonged outdoor exposure and inadequate hydration. In addition,
the combination of warm temperatures and increasing winds will
maintain the potential for elevated fire danger, particularly across
southern and coastal areas where fuels will continue to dry.

&&

.AVIATION...
(06Z TAFS)
Issued at 452 AM AST Wed May 6 2026

Mainly VFR conds expected across all terminals through the fcst pd.
However, brief VCSH possible across eastern terminals and TJBQ aft
06/17Z due to isolated SHRA/SHRA development. A PROB30 group remains
in place for TJBQ btwn 06/17-21Z for psbl brief MVFR conds for
VCTS/TSRA. Winds will remain generally E-SE at 10-15 kt with
occasional higher gusts and sea breeze variations, becoming light
and variable overnight.

&&

.MARINE...
Issued at 452 AM AST Wed May 6 2026

Broad surface highs and frontal lows over the Atlantic will promote
up to moderate easterly to east-southeasterly winds through today,
then backing to become more east to east-northeast later tonight
through Sunday. By the weekend, winds are also expected to increase
to moderate to fresh levels across the regional waters. Seas will
range between 2 and 4 feet, occasionally higher due to a combination
of local wind waves and a few pulses of a small, long-period
northeasterly swell spreading across the Atlantic waters. Conditions
will be generally favorable for small craft, though operators should
exercise caution at times due to wind-driven seas and passing showers
that may produce locally higher winds and seas.

&&

.BEACH FORECAST...
Issued at 452 AM AST Wed May 6 2026

Up to a moderate risk of rip currents (life-threatening rip currents
are possible in the surf zone) are forecast to continue today for
the north and east beaches of Puerto Rico, as well as for exposed
beaches of Culebra. 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. A similar pattern will continue at least
through at least tomorrow, Thursday, afternoon. A low risk of rip
currents is then forecast to dominate across most beaches Thursday
night through early Saturday. By Saturday afternoon and into the
rest of the weekend and the start of the next workweek, breezier
winds prompt a return of the moderate rip current risk which will
gradually spread to most beaches to start the workweek. For
additional information, visit: weather.gov/beach/sju.

&&

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

$$

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

NWS SJU Office Area Forecast Discussion