394
FXCA62 TJSJ 120855
AFDSJU

Area Forecast Discussion
National Weather Service San Juan PR
455 AM AST Wed Feb 12 2025

.SYNOPSIS...

Breezy conditions will continue across the local islands, impacting
outdoor activities and operations. Small craft operators should
avoid hazardous seas caused by winds, which will continue into the
weekend. Low humidity, breezy conditions, drying soils, and available
fuels will create favorable conditions for fire spread today.

&&

.SHORT TERM...Today through Friday...

Isolated to scattered showers were seen over the regional waters
overnight, with some activity reaching the northern and eastern
portions of Puerto Rico, and the U.S. Virgin Islands. It was breezy
too, with sustained winds up to 12 mph in the coastal areas, with
wind gusts at 15 to 20 mph. Minimum temperatures were seen in the
upper 50s in the mountains, to the low to mid 70s in the coastal and
urban areas.

A strong surface high pressure over the central Atlantic will
continue to tighten the local pressure gradient, resulting in fresh
to strong easterly winds across the region. A mid-to-upper level
high pressure ridge over the northeastern Caribbean will continue to
promote drier air stable conditions aloft. Given the current weather
conditions, patches of moisture will continue to move into the area,
promoting showers across the windward portions of the islands. Then,
the combination of the available moisture with local effects, and
daytime heating will result in afternoon convective activity across
the interior and western municipalities of Puerto Rico.

By Thursday into Friday, the mid-to-upper level ridge is expected to
slightly erode as a mid-level shortwave trough move over the area.
The latest precipitable water (PWAT) has values between 0.80 to 1.60
inches throughout the period, with slightly higher values on Thursday
night and Friday morning. The overall weather pattern will continue
very similar for the next few days with the arrival of patches of
moisture embedded in the trades, resulting in showery weather at
times. Seasonal temperatures will remain across the region with near
to above normal temperatures. Highs will remain in the mid 80s along
the coastal and urban areas of Puerto Rico and the U.S. Virgin
Islands, and from the upper 70s to low 80s in the higher elevations.

.LONG TERM...Saturday through Wednesday...

Based on the latest model guidance, weather conditions are expected
to remain variable throughout the forecast period, influenced by an
eastward-moving surface high pressure over the North Atlantic and
mid-level ridging. As the surface high shifts farther eastward, some
variations in the general wind flow are likely, but winds should
generally remain easterly at 15-25 mph, with higher gusts. The
expected breezy conditions will steer intermittent patches of
shallow moisture and drier air across the northeastern Caribbean,
resulting in periodic moisture fluctuations every 24-36 hours.
Precipitable water values will range from around 0.9-1.1 inches
during the driest periods to 1.6-1.7 inches during the wettest
periods. Mid-level ridging will promote hostile conditions for deep
convective development, with a marked trade wind cap inversion and
drier air aloft, particularly by the latter part of the long-term
forecast. If convection develops, particularly during the afternoon
hours, it is expected to remain mostly shallow.

Overall, variable weather conditions are anticipated, with an
increased frequency of trade wind showers and possible afternoon
convective development during high-moisture periods. The highest
impacts will primarily affect windward sections of the islands,
though strong steering flow may push trade wind showers further
inland. Additionally, afternoon convective development could bring
periods of moderate to locally heavy rainfall to other areas.
However, excessive rainfall impacts should remain limited at most,
with the main risks being ponding of water on roadways and in poorly
drained areas.


&&

.AVIATION...
(06Z TAFs)

Mainly VFR conds are expected to prevail across all terminals during
the next 24 hours. Trade wind showers could move at times over the
TJSJ/TIST/TISX terminals thru 12/14Z. E winds will prevail btw 15-20
kts with sea breeze variations and higher gusts aft 12/14Z.

&&

.MARINE...

A surface high pressure over the central Atlantic will maintain
fresh to locally strong east winds. These conditions will persist
throughout the workweek, resulting in rough and hazardous seas
across most local waters. Passing showers may develop at times
throughout the workweek promoting stronger gusty wind conditions in
localized areas.

&&

.BEACH FORECAST...

For today, there is a moderate risk of rip currents across most of
the beaches in Puerto Rico (including Vieques and Culebra) and
the U.S. Virgin Islands. Similar conditions are expected to
continue into the weekend. This means that life-threatening rip
currents are possible in the surf zone and beachgoers must stay
alert and be careful.

&&

.FIRE WEATHER...

Drier conditions and stronger winds will contribute to an increased
fire danger risk today across the region. A drier air mass moving
through will limit moisture recovery, keeping relative humidity
values in the low to mid-40s across southern coastal plains and
around low to mid 50s elsewhere. Winds are expected to
strengthen, ranging from 20-30 mph, with higher gusts, further
exacerbating fire danger conditions by enhancing fire spread
potential. Given these expected conditions and KBDI values
remaining above 550, an RFDSJU has been issued due to the elevated
risk of fire spread.

&&

.SJU WATCHES/WARNINGS/ADVISORIES...
PR...None.
VI...None.
AM...Small Craft Advisory until 6 PM AST Friday for AMZ711-712-716-
     723-726-733-735-741.

&&

$$

SHORT TERM/AVIATION...GRS
LONG TERM/MARINE/BEACH...CVB