NWS San Juan, PR wrote its last area forecast discussion before the first event at Feb 19, 9:33 PM AST, 2 hours 27 minutes earlier.
Area forecast discussion, Feb 19, 9:33 PM AST, 2 hours 27 minutes before
Area Forecast Discussion
National Weather Service San Juan PR
933 PM AST Sat Feb 19 2022
.UPDATE...Showers lingered over the southwest quadrant of Puerto
Rico through the early evening hours. Estimated rainfall
accumulations through 8 PM AST were between 0.50-2.00 inches, with
the highest amounts in Guayanilla, Lajas, and San Sebastian. Also,
mid-to-late afternoon showers developed downwind from el Yunque into
the eastern interior sections, leaving between 0.50-1.25 inches of
rain. Across the northern and eastern sections of PR, isolated
showers were noted with up to a quarter of an inch of rain observed.
Lesser amounts were observed across the USVI. For the rest of
tonight into Sunday morning, a moderate northeasterly steering wind
flow will bring at times showers across portions of northern and
eastern PR, and across the USVI. However, rainfall amounts should
not be significant as an area of drier mid-level air is moving from
the east. This is evident in the 20/00z sounding as it showed 1.15
inches of PWAT. Minor changes were made to the previous forecast.
&&
.AVIATION...Mainly VFR conditions are expected to prevail across all
terminals during the next 24 hours. However, trade winds showers
could move at times across TJSJ/TJBQ and the USVI terminals through
the period, causing brief MVFR cigs. The 20/00z TJSJ sounding
indicated NE winds at up to 15 kt blo FL100.
&&
.MARINE...No significant change from previous discussion. SCA due to
7 ft seas continues in effect for the offshore Atlantic waters,
while small crafts should continue to exercise caution across the
rest of the northern coastal waters and passages. East to northeast
trades between 10 and 15 kt will continue through Sunday. Life-
threatening rip currents will continue on Sunday across the Atlantic
coastline of PR, Culebra and St. Thomas, and as well as across the
north and eastern beaches of St. Croix.
&&
.PREV DISCUSSION... /issued 505 PM AST Sat Feb 19 2022/
SYNOPSIS...
A typical weather pattern continues across the region. Passing
showers affecting the local waters and windward portions of the
islands are expected. In the afternoons, shower development is
anticipated, mostly affecting southwestern portions of Puerto Rico,
as the wind flow remains generally northeasterly for the next
several days.
SHORT TERM...Tonight through Monday...
A slot of drier air is making its way into the region, and will
affect the area into tomorrow, with patchy moisture behind it
tomorrow into Monday. The drier air will inhibit somewhat the shower
development. Meanwhile, the ridge aloft will maintain stability into
tomorrow, causing further inhibition of showers. Even so, passing
showers are expected to continue to affect the area, especially over
the waters and in windward portions of the island, in the east and
northeast, including for the San Juan metro area. Much like today,
afternoon showers are anticipated, mostly in southwestern portions
of Puerto Rico, with streamers possible off of the smaller islands
to the east.
The mid-level ridge will erode somewhat starting late tomorrow, and
stability will decrease. A modest increase in moisture over the
region is also anticipated. As such, an increase in shower activity
is likely. With winds remaining generally northeasterly, the overall
shower pattern will be maintained, affecting northeastern portions
of the islands with passing showers and southwestern and interior
portions of Puerto Rico being affected by afternoon showers.
LONG TERM...Tuesday through Saturday...From Prev Discussion...
A mid to upper-level ridge will continue over the Northeast
Caribbean through Tuesday or Wednesday. Then it is forecast to
weaken as a mid to upper- level trough amplifies near the
Northeast Caribbean from the Central Atlantic. Although the ridge
aloft will promote stable weather conditions, the trade winds will
bring patches of clouds and showers across Puerto Rico and the
U.S. Virgin Islands at times.
Upper-level low digs southward and re-locates east or northeast
of the Lesser Antilles from mid-week to the following weekend.
Although the ridge should weaken, the islands will remain on the
subsidence side of the low pressure aloft. However, cold air
advection will promote the typical overnight and early morning
showers, followed by limited afternoon convection across the
western sections. Surface-induced troughs will bring more frequent
showers Friday and Saturday.
AVIATION...
Passing low lvl clds nr FL025...FL040 and ISOLD-SCT SHRA will
continue across the region durg the prd steered by the dominant
northeast low level wind flow. Brief Mtn Top obscr psbl ovr the
central Mtn range of PR durg aftn due to low clds/SHRA. VFR conds
are expected at all terminals but VCSH will remain possible at
most terminals. Winds will continue from the northeast btw 12-15
kts with brief gusts to 20-25 kts til 19/23Z. Winds will decrease
overnight bcmg less than 10 kts mainly fm ENE, but will again
increase once again to nr 15 kts with ocnl gusts after 20/14Z. No
sig operational wx impacts attm.
MARINE...
Buoy 41043 has shown gradually decreasing wave heights during the
day today, and seas of around 7 to 7.5 feet have been reported over
the last several hours. For the buoys at San Juan and Arecibo, seas
of around 5.5 feet have been reported. Winds are diminishing
somewhat, and will be generally between 10 and 15 knots across the
waters. As such, there will still be some choppy conditions across
the waters, for those areas exposed to the east/northeast. Seas will
continue to subside, and conditions are now expected to no longer
meet hazardous criteria within the local waters by early tomorrow
morning. However, conditions will remain near hazardous criteria,
and operators of small craft should exercise caution.
Currently expecting building seas again by Monday or Tuesday, when
hazardous conditions could return, with another increase in winds
across the region.
There is a high risk of rip currents for most local beaches,
including northwestern and northern Puerto Rico, northwestern St.
Thomas, and beaches of Culebra and St. Croix. For Vieques, the risk
will decrease tonight, becoming mostly moderate risk.
&&
.PRELIMINARY POINT TEMPS/POPS...
SJU 73 82 73 83 / 50 40 70 70
STT 73 82 73 84 / 40 40 50 40
&&
.SJU WATCHES/WARNINGS/ADVISORIES...
PR...High Rip Current Risk through late Monday night for Culebra-
North Central-Northeast-Northwest-San Juan and Vicinity-
Southeast.
High Rip Current Risk until 6 AM AST Sunday for Mayaguez and
Vicinity.
VI...High Rip Current Risk through late Monday night for St Croix-
St.Thomas...St. John...and Adjacent Islands.
AM...Small Craft Advisory until 8 AM AST Sunday for Atlantic Waters
of Puerto Rico and USVI from 10 NM to 19.5N.
&&
DSR/LIS