Puerto Rico, 2001

Flash Flooding in Puerto Rico, May 8, 2001

May 8, 2001 · NWS SJU · 2 events in 2 counties and zones

A mid to upper level trough in the vicinity of the local area combined with daytime heating and sea breeze influences caused strong thunderstorms over the San Juan Metropolitan area. Due to previous rains, ground was saturated, and flash flooding occurred.

The toll

Deaths
0
Injuries
0
Property damage
$40,000
Crop damage
None recorded
Events
2

Deaths and injuries are direct and indirect together, as the offices filed them. Damage is property and crops in the dollars of the year, not adjusted for inflation, and only where an office estimated it.

What happened

The episode as NWS SJU wrote it up.

A mid to upper level trough in the vicinity of the local area combined with daytime heating and sea breeze influences caused strong thunderstorms over the San Juan Metropolitan area. Due to previous rains, ground was saturated, and flash flooding occurred. Several homes flooded in Loiza and Trujillo Alto. Also several streets flooded in the San Juan Metropolitan Area.

What forecasters said that day

The local office's own words before the first event, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS San Juan, PR wrote its last area forecast discussion before the first event at May 8, 2:05 PM AST, 3 hours 55 minutes earlier.

Area forecast discussion, May 8, 2:05 PM AST, 3 hours 55 minutes before
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
205 PM AST TUE MAY 8 2001

MODELS IN GENERALLY GOOD AGREEMENT BUT BELIEVE THAT NGM IS VERIFYING
WELL AND WILL THEREFORE FOLLOW IT CLOSELY AT THIS TIME. WITH THIS IN
MIND...BASED ON SATELLITE I CAN SEE TWO AREAS OF MOISTURE
CONVERGENCE...ONE MOVING ACROSS US AT THIS TIME AND ANOTHER SOUTH OF
U.S.V.I. LOW TO THE NORTHWEST WITH TROUGH AXIS EXTENDING TO
HISPANOLA WILL BEGIN TO PULL NORTHWARD. AS THE LINGERING TROUGH
PULLS NORTH OF THE AREA TONIGHT RESULTING IN AN INDUCED LOW LEVEL
TROUGH TO SET UP TEMPORARILY JUST WEST OF LOCAL AREA PULLING THE
MOISTURE CURRENTLY SOUTH OF THE U.S. VIRGIN ISLANDS ACROSS US.

PUERTO RICO AND U.S. VIRGIN ISLANDS TO REMAIN IN THE SOUP THROUGH
NOON ON WEDNESDAY BEFORE WE SEE THE MAJORITY OF THE MOISTURE PULL
NORTH OF AREA. SATELLITE ANALYSIS SHOWS A BREAK BETWEEN MOISTURE
MOVING THROUGH AND ANOTHER SHOT WHICH I WILL WILL MOVE THROUGH
TONIGHT. THIS BEING THE CASE WITH ENOUGH MOISTURE LINGERING ON
WEDNESDAY AFTERNOON DIURNAL PATTERNS WILL BE THE DEFINING
THUNDERSTORMS PRODUCER. ALTHOUGH NO LARGE SCALE LIFT IN
ORDER...CONDENSATION PRESSURE DEFICIT INDICATES THAT ONLY A SMALL
AMOUNT OF LIFT WILL BE NEEDED TO GET CONDENSATION. THIS BEING THE
CASE WILL INCREASE POPS AND CHANCE OF THUNDERSTORMS FOR TONIGHT.

.PRELIMINARY NUMBERS...
SJU EB 075/085 077/087 076 15463
STT EB 075/086 078/086 077 15753=

EQUIPMENT: NO PROBLEMS AT THIS TIME.

.SJU...
.PR...FFA ALL VT22Z.
.VI...NONE.

TIRADO

WRITTEN TEXT FORECASTS (IN ENGLISH OR SPANISH)...SATELLITE IMAGERY
...DOPPLER RADAR DATA...AND A VIRTUAL LIBRARY OF WEATHER INFORMATION |
CAN BE FOUND AT THE NWS SAN JUAN WEB SITES AT:

HTTP://WWW.SRH.NOAA.GOV/SJU (ALL LOWER CASE).

    OR

HTTP://WWW.UPR.CLU.EDU/NWS (ALL LOWER CASE).

Event by event

2 flash flood. Local standard time, as filed.

Flash Flood, San Juan and Vicinity

When
May 8, 6:00 PM AST to 9:00 PM AST
Where
San Juan and Vicinity County, Countywide
Property damage
$25,000
Reported by
NEWSPAPER

Flash Flood, Northeast

When
May 8, 6:00 PM AST to 9:00 PM AST
Where
Northeast County, West Portion
Property damage
$15,000
Reported by
NEWSPAPER

What these are

Flash Flood
Flooding that begins within six hours of the rain that causes it, or of a dam or levee failure or ice jam release, often with deadly speed.

After NWS Directive 10-1605, the rules offices file Storm Data by.

The same day elsewhere

More

Every storm in Puerto Rico in 2001Every state in 2001This day in weather historyWarnings in Puerto Rico, May 2001

Sources

NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-09-24. Each event’s entry at NCEI: 5250247, 5250248.