Flood in Guam, April 28, 2003

Name: Flood in Guam, April 28, 2003
Start: 2003-04-28T15:00
End: 2003-04-28T20:00
Location: Guam

April 28, 2003 · NWS GUA · 1 event in 1 county or zone

Favorable upper level winds enhanced rainshowers over Saipan. This caused flooding in poor drainage areas over the island.

The toll

Deaths: 0
Injuries: 0
Property damage: None recorded
Crop damage: None recorded
Events: 1

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 GUA wrote it up.

Favorable upper level winds enhanced rainshowers over Saipan. This caused flooding in poor drainage areas over the island. Residents in Susupe sought help from authorities due to flood water entering their houses. Residents of Tanapang also complained of floodwater. At around 1630, the wastewater pump in Garapan broke down due to too much rainwater getting into the system.

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 GUA wrote its last area forecast discussion before the first event at Apr 28, 3:58 AM SST, 11 hours 2 minutes earlier.

Area forecast discussion, Apr 28, 3:58 AM SST, 11 hours 2 minutes before

AREA SYNOPTIC DISCUSSION
NATIONAL WEATHER SERVICE TIYAN GU
1 AM GUAM LST TUE APR 29 2003

WESTERN NORTH PACIFIC BETWEEN EQUATOR AND 25N FROM 130E TO 180.

A TROUGH OF LOW PRESSURE EXTENDS FROM 4N130E NORTHEASTWARD THROUGH A
WEAK CIRCULATION CENTER NEAR 5N134E TO 15N138E. CONVERGENT LOW-LEVEL
WIND FLOW EAST OF THE TROUGH IS GENERATING SCATTERED SHOWERS AND
ISOLATED THUNDERSTORMS WITHIN 120 MILES OF A LINE FROM 3N137E TO
16N138E...INCLUDING YAP.

DIVERGENT WINDS ALOFT ARE PRODUCING SCATTERED SHOWERS BETWEEN 12N
AND 20N FROM 144E TO 150E...INCLUDING THE MARIANA ISLANDS.

TRADE WIND CONVERGENCE IS GENERATING NUMEROUS SHOWERS AND ISOLATED
THUNDERSTORMS FROM KOSRAE EASTWARD THROUGH THE MARSHALL ISLANDS...
BETWEEN 3N AND 10N FROM 165E TO 178E.

CONVERGENT LOW-LEVEL FLOW ALONG THE EQUATOR IS GENERATING SCATTERED
SHOWERS AND ISOLATED THUNDERSTORMS BETWEEN THE EQUATOR AND 5N FROM
139E TO 153E.

Event by event

1 flood. Local standard time, as filed.

Flood, Saipan

When: April 28, 3:00 PM SST to 8:00 PM SST
Where: Saipan forecast zone
Reported by: NEWSPAPER

What these are

Flood: Flooding that develops more slowly than a flash flood: rivers leaving their banks, or water standing over land for an extended time.

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

The same day elsewhere

Every storm in Guam in 2003 Every state in 2003 This day in weather history Warnings in Guam, April 2003

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: 5355614.