Hydrologic Outlook issued May 15 at 12:30PM AST by NWS San Juan PR

ESFSJU

An upper-level trough moving across the northeast Caribbean combined
with abundant moisture will result in showers and thunderstorms
across the local island Friday and Saturday.

Based on the latest guidance, there is a chance to observe periods
of showers and thunderstorms Friday and Saturday. The areas expected
to receive the highest rainfall totals include northwest, central
and the eastern coastal areas of Puerto Rico as well as Vieques,
Culebra and the US Virgin Islands. Across these areas there is a
moderate chance(40-60%) to observe 2 to 4 inches with locally higher
amounts of up to 6 inches. Due to already saturated soils and rivers
and tributaries running well above normal levels, there is a risk
for flooding across Puerto Rico and the US Virgin Islands on Friday
and Saturday.

Any prolonged period of heavy rainfall will result in urban and
flash flooding, river flooding and mudslides particularly across
central and east Puerto Rico where rainfall has been abundant over
the past month.