Advisory FFA Flood Watch — Sat Oct 28, 2023 5:34 AM

FFASJU) issued by WFO San Juan PR.

.LONG TERM...Tuesday through Saturday...

The period will start with a mid- to upper- level ridge overhead of
the islands. Model guidance suggests a mid- to upper- level trough
building to our east slowly eroding the ridge throughout the long
term period and gradually increasing instability aloft. GFS model
suggests precipitable water (PWAT) values up to around 2.4 inches
across the region Tuesday, decreasing to around 2.0 inches on
Wednesday with drier air filtering in on late Thursday and Friday,
and finally more moist air filtering in again and increasing PWAT to
around 2.0 inches on Saturday. Southerly windflow will persist over
the area through Thursday, helping lift tropical moisture into the
area from the ITCZ. Winds are forecast to become more easterly and
increase late Thursday and into Friday. Although the environment
will remain moist, the driving force for the afternoon convection
will be diurnally induced to start the period, as conditions will be
more stable aloft during that time, with additional instability from
perturbations reaching the region and a lingering surface trough.
Instability aloft due to the mid- to upper- trough and and increase
in moisture will in turn increase rain chances during to end the
period. Discrepancies continue between the GFS and the ECMWF model
but already saturated soils from events in the short term period
increase the potential for urban, small stream and flash flooding,
along with mudslides in areas of steep terrain. Please continue to
monitor future updates.

&&

.AVIATION...Variably cloudy skies and unsettled weather conds
will persist across the flying area due to the interaction of a mid-
upper-level trough and broad surface trough spread across the
region. SCT-BKN cld lyrs nr FL025...FL040...FL090 and BKN-OVC nr
FL250. SHRA/Isold TSRA ovr lcl waters and en route between the local
terminals. TIST/TISX can expect prds of MVRF/IFR conds due to
SHRA/Isold TSRA, and VCSH at TJSJ til 28/12Z. Late morning and aftn
SHRA/Isold TSRA dvlpmnt fcst btw 28/16-22z around the islands with
MTN top obscr ovr PR due to low cig w/SHRA/ Isold TSRA. SFC wnd calm
to LGT/VRB, BCMG fm ESE/SSE around 10 kt aft 28/14z. Hir gusts with
aftn convection.

&&

.MARINE...Hazardous marine and coastal conditions will persist
through early next week due to northerly swells. Small Craft
Advisories are in effect for the Atlantic Offshore Waters and
Caribbean Passages until at least late Sunday night due to seas
between 8 and 12 feet. At 5 AM AST the San Juan, Arecibo and
Rincon CariCOOS buoys reported 7-10 foot wave heights with
periods of 13-14s. Beachgoers, avoid the Atlantic Coastline in
Puerto Rico and the U.S. Virgin Islands due to hazardous coastal
conditions. Please see the CFWSJU and MWWSJU products for more
information.

&&

.SJU WATCHES/WARNINGS/ADVISORIES...
PR...Coastal Flood Advisory until 6 PM AST this evening for PRZ001-
     002-005-008.

     Flood Watch through Monday morning for PRZ001>013.

     High Rip Current Risk through Monday morning for PRZ001-002-005-
     008-010-012-013.

     High Surf Advisory until 6 PM AST Sunday for PRZ001-002-005-008-
     010-012-013.

VI...Flood Watch through Monday morning for VIZ001-002.

     High Rip Current Risk through Monday morning for VIZ001-002.

     High Surf Advisory until 6 PM AST Sunday for VIZ001.

AM...Small Craft Advisory until 6 AM AST Monday for AMZ711-712-716-
     723-726-741-742.

&&

$$