National Weather Service San Juan PR
445 AM AST Wed Feb 22 2023
.SYNOPSIS...A mid-level ridge will continue to promote overall
stable conditions across the islands through most of the forecast
period. Moisture increases briefly on Saturday due to remnants of
an old frontal boundary. Moderate to locally fresh northeasterly
trades are expected to prevail for the next several days.
&&
.SHORT TERM...Today through Friday...
Mid-level ridge will hold for the rest of the workweek maintaining
an 850-800 mb inversion cap in place with dry air and stable weather
conditions persisting aloft. Recent satellite imagery shows an
elongated band of cloud coverage approaching the local islands,
currently south of Saint Croix extending northeastward towards the
northern Leeward Islands. Precipitable water (PWAT) values
associated with this band of clouds are near 1.0 inches to at most
1.10 inches which will reach the area during the morning hours into
early afternoon. The bulk of moisture, however, is expected to
remain well south over the Caribbean waters. Although PWAT will
slightly increase for the USVI, Vieques, Culebra, and eastern
portions of Puerto Rico, little to no rain is expected as low-level
moisture content will still be well below normal across these
regions. Diurnal heating and sea breeze convergence may enhance
shower activity across southwestern portions of Puerto Rico in the
afternoon, but no significant rainfall accumulations are
anticipated.
Breezy wind conditions will also prevail, especially on Thursday and
Friday as the surface high pressure over northwestern Atlantic
strengthens. The induced northeasterly trades will push patches of
moisture across the region from time to time promoting a cold
advective pattern. This will favor passing showers across portions
of the local islands, especially the windward sections at night and
early in the morning hours. Then, local effects and sea breeze
convergence will combine to produce scattered showers over the
southwestern portions of Puerto Rico each afternoon. Therefore,
Thursday and Friday will be the wettest days of the short-term
period, but once again rainfall accumulations are not expected to be
significant.
.LONG TERM...Saturday through Wednesday...
A low-level ridge over the southwestern Atlantic will maintain a
moderate to locally fresh northeasterly winds flow across the
area through the weekend. The remnants of an old front are
expected to reach the islands on Saturday. Moisture will briefly
increase(1.30-1.50 inches of PWAT), and scattered showers are
possible across the islands throught the day. Drier air follows on
Sunday and PWAT returns to below seasonable levels. A slight weakening
of the ridge is also expected, as it move slowly eastwards
through the end of the long term period. This will cause winds to
shift more from the east by Tuesday. Meanwhile, the mid-level
ridge over the Caribbean basin will promote stable conditions and
drier air aloft through the entire period. Overall, fair weather
conditions should prevail through much of the long term period.
Minor rainfall accumulations are expected in general across the
islands.
&&
.AVIATION...Mainly VFR conditions are expected to prevail across all
terminals during the next 24 hours. A broad patch of low to mid
level clouds may briefly create SCT-BKN ceilings at FL050-FL070 with
mostly very isolated SHRA over the regional waters causing brief
MVFR, but with limited operational impacts at terminals during
period. Low-level winds will continue from the E-NE at 15-20 kt,
with occasional higher gusts after 22/14Z.
&&
.MARINE...Offshore buoy 41043 indicated a 5 ft northeast swell at
9 seconds. This small swell will continue to slowly subside
today, but the wind-driven (15-20 kt) seas are expected to return
on Thursday, maintaining seas between 3 to 5 ft through the end
of the week across most of the local waters. A moderate risk of
rip currents will prevail along the north and east facing beaches
of the islands. A long period northerly swell is forecast to reach
the local Atlantic waters and passages by late Sunday into
Monday. Seas could build up to 7 feet across the offshore Atlantic
waters, and the risk of rip currents will increase once again
across the north facing beaches of the islands.
&&
.SJU WATCHES/WARNINGS/ADVISORIES...
PR...None.
VI...None.
AM...None.
&&
$$
SHORT TERM/AVIATION...CVB
LONG TERM/MARINE...DSR