374
FXCA62 TJSJ 050921
AFDSJU

Area Forecast Discussion
National Weather Service San Juan PR
521 AM AST Wed Feb 5 2025

.SYNOPSIS...

Variable weather will persist during the next several days with
passing showers moving from time to time over windward areas.
Localized afternoon convection is possible across the interior to
W-SW PR. Small craft operators should take action to avoid hazardous
seas caused by breezy conditions, which will continue through the
week and into the weekend. Life-threatening rip currents are
possible, especially along northwestern, northern and eastern
Puerto Rico, Vieques, Culebra and the U.S. Virgin Islands.

&&

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

East-northeast winds steered shower activity into mainly northern
and eastern Puerto Rico, as well as Culebra and St. Thomas, during
the overnight hours. From midnight to 4 AM AST, radar estimated
precipitation indicated areas with above 0.2 inches of rainfall over
the above mentioned areas. In the same time frame, areas above 0.3
inches were observed over northwestern and eastern Puerto Rico. The
municipalities of Quebradillas (0.40 in), Camuy (0.49 in) and
Fajardo (0.64 in) saw the highest radar estimated rainfall from
midnight to 4 AM AST. Reported minimum temperatures have been in the
low to mid 60s at higher elevations of Puerto Rico and in the low to
mid 70s at lower elevations of the islands.

Satellite-derived precipitable water (PWAT) values indicate a
surface perturbation over Puerto Rico, with PWAT values ranging from
1.4 to 1.5 in over land, at normal to above normal levels. Current
model guidance suggest this patch of moisture gradually moving west
and out of the area today. However, during the morning hours, the
advective pattern will continue to affect windward areas of the
islands as showers move in. A mid-level trough continues to erode
the mid level ridge, helping to increase instability and moisture.
During the afternoon hours, convective showers will result in
showers over the interior to west-southwest Puerto Rico. The patch
of moisture should be over the Mona Passage by tonight, with drier
air elsewhere, with PWAT values at below to around 1.20 inches.
Additional patches of moisture (with advective showers) will move
into the area during the rest of the period, especially during the
overnight to morning hours, while afternoon convection affects
western Puerto Rico. Although, ENE winds are forecast to be lighter
today than during the past few days by tonight into Thursday, a
surface high will move off the eastern U.S. coast will ultimately
promote breezy conditions through the rest of the workweek. 925mb
temperatures will remain near normal. Highs can reach the low to mid
80s (locally higher especially in W-SW-S PR) across lower elevations
of the islands. Lows can reach around the low 60s at higher
elevations of Puerto Rico, and from the low to mid 70s across lower
elevation of the islands. Low concentrations of Saharan Dust will
also be present today. Patchy fog can also be present during the
overnight to early morning hours across sectors of interior Puerto
Rico.

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

A surface high pressure system will be centered northeast of the
area during the weekend, but will extend north of the area early
next week. This will maintain a tight pressure gradient, with breezy
east-northeasterly winds during the weekend, and breezy to locally
windy conditions but with a more easterly component during the first
half of next week. These winds will keep an advective pattern with
patches of moisture reaching our area from time to time, increasing
the frequency of passing showers across the windward sections of the
islands. A series of weak mid to upper level troughs will maintain
some instability aloft during the weekend, allowing the moisture
layer to extend from the surface up to just under 500mb.
Precipitable Water (PWAT) values will fluctuate between 1.1 and 1.6
inches during the weekend, with the passage of the moisture patches.
This will help boost the rainfall pattern during the afternoons,
with an increase in convective activity.

Relatively drier conditions will follow early next week as a mid
level ridge builds just north of our area. However, patches of
moisture will continue to stream across the area from time to time.
Precipitable Water (PWAT) will range from 1.1 to 1.4. Temperatures
will continue near seasonal levels during the period with highs
ranging from the low to mid 80s across lower elevations (locally
higher over W-SW-S PR). Minimum temperatures can reach the upper 50s
to 60s across higher elevations, and from the low to mid 70s across
lower elevation of the islands. Patchy fog are possible during the
overnight to early morning hours across the interior valleys of
Puerto Rico.

&&

.AVIATION...

(06Z TAFs)

Mainly VFR conditions during the period. However, SCT SHRA steered
by E-NE winds will mainly affect northern and eastern terminals
during the morning hours, which can lead to brief MVFR conditions.
VCSH can also affect TJPS btw 05/16-22Z. SFC winds will be from the
E-NE up to around 15 kts, with higher gusts, after 05/14Z.

&&

.MARINE...

A surface high pressure over the western Atlantic migrating eastward,
will maintain moderate to fresh east-northeast winds. As this high
builds, winds will become stronger by the latter part of the workweek
and the upcoming weekend. As a result,choppy seas and hazardous
conditions for small crafts are expected across the offshore
Atlantic, while choppy seas will persist elsewhere.

&&

.BEACH FORECAST...

A moderate rip current risk will continue for the rest of the week
in most exposed beaches. Specific north-facing beaches, and other
less sheltered coastal areas may present a higher danger to
swimmers and beachgoers. It is possible that the rip current risk
increases to high during the weekend. Beachgoers must stay alert
and avoid dangerous waters. For more information please refer to
the latest Surf Zone Forecast (SRFSJU).

&&

.SJU WATCHES/WARNINGS/ADVISORIES...
PR...None.
VI...None.
AM...Small Craft Advisory until midnight AST Sunday night for AMZ711.

     Small Craft Advisory from 6 AM Thursday to midnight AST Sunday
     night for AMZ723.

&&

$$

SHORT TERM...MRR
LONG TERM....KML/ICP/MRR
AVIATION...MRR
MARINE...ICP
BEACH FORECAST...ICP/KML