Tropical Storm in Guam, September 19 to 21, 2004

Name: Tropical Storm in Guam, September 19 to 21, 2004
Start: 2004-09-19T12:00
End: 2004-09-21T12:00
Location: Guam

September 19 to 21, 2004 · NWS GUA · 1 event in 1 county or zone

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.

TROPICAL DEPRESSION 25WTropical Depression 25W (TD 25W) developed about 300 miles east of Guam on the afternoon of September 19th. Moving steadily west at about 20 mph, TD 25W passed 30 miles south of Guam's southern tip at about 1300 SST on the 20th, with maximum sustained winds of 30 to 35 mph. By 1000 SST on the 21st, TD 25W had become Tropical Storm Meari, centered 210 miles west of Guam with maximum winds of 40 mph near the center. During its passage, TD 25W brought gusty winds and heavy rain to Guam, but no injuries or damage were reported. From the 19th through the 21st, 5.75 inches of rain fell at Guam International Airport, including 2.90 inches on the 20th. Both the maximum sustained wind of 32 mph and the peak gust of 44 mph from the northeast were recorded in heavy rain at 0735 SST the morning of the 20th. The lowest sea level pressure was 1006.6 mb, recorded on the afternoon of the 20th at 1454 SST and again at 1654 SST.

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 Sep 19, 9:25 AM SST, 2 hours 35 minutes earlier.

Area forecast discussion, Sep 19, 9:25 AM SST, 2 hours 35 minutes before

AREA SYNOPTIC DISCUSSION...CORRECTED
NATIONAL WEATHER SERVICE TIYAN GU
6 AM GUAM LST MON SEP 20 2004

CORRECTED POSITION OF TROPICAL DISTURBANCE

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

A TROPICAL DISTURBANCE LOCATED AROUND 100 MILES SOUTHEAST OF GUAM
NEAR 13N146E IS NOW THE SUBJECT OF A TROPICAL CYCLONE FORMATION
ALERT ISSUED BY THE JOINT TYPHOON WARNING CENTER (JTWC). A TROPICAL
CYCLONE FORMATION ALERT MEANS THE FORMATION OF A SIGNIFICANT
TROPICAL CYCLONE IS POSSIBLE WITHIN 24 HOURS. SEE THE JTWC BULLETIN
UNDER WMO HEADER WTPN21 PGTW FOR MORE DETAILS.

A MONSOON TROUGH EXTENDS FROM 7N130E TO A TROPICAL DISTURBANCE EAST
OF THE MARIANAS NEAR 13N148E TO ANOTHER WEAK CIRCULATION JUST WEST
OF KWAJALEIN NEAR 10N165E TO 7N170E. LOW-LEVEL CONVERGENCE SOUTH OF
THE TROUGH AXIS IS PRODUCING SCATTERED SHOWERS AND ISOLATED
THUNDERSTORMS SOUTH OF PALAU AND YAP BETWEEN THE EQUATOR AND 5N FROM
134E TO 138E...AND WITHIN 100 MILES OF A LINE FROM EQ149E TO 9N154E
WHICH INCLUDES CHUUK.

NUMEROUS SHOWERS AND SCATTERED THUNDERSTORMS ARE FOUND WITHIN 100
MILES OF THE CIRCULATION CENTERED EAST OF THE MARIANAS...WHILE
SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS EXTEND AS FAR AS 200
MILES FROM THE CIRCULATION CENTER.

SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS ASSOCIATED WITH THE
WEAK CIRCULATION NEAR KWAJALEIN ARE FOUND BETWEEN 9N AND 14N FROM
160E TO 166E.

A SHEAR LINE IS CAUSING SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS
WELL NORTH OF THE MARIANAS AND WAKE ISLAND...WITHIN 100 MILES OF A
LINE FROM 24N142E EASTWARD TO 25N166E.

TRADE WIND CONVERGENCE IS GENERATING SCATTERED SHOWERS SOUTHEAST OF
WAKE WITHIN 100 MILES OF A LINE EXTENDING FROM 25N171E TO
7N178E...AND SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS ARE FOUND
SOUTHEAST OF MAJURO WITHIN 60 MILES OF A LINE EXTENDING FROM EQ175E
TO 5N180.

In the hours before

Special weather statement, Sep 19, 9:45 AM SST, 2 hours 15 minutes before

GUZ001-002-003-004-200600-
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE TIYAN GU
645 AM LST MON SEP 20 2004

...DEVELOPING TROPICAL DISTURBANCE SOUTHEAST OF GUAM...

AT 6 AM LST...A TROPICAL DISTURBANCE WAS LOCATED AROUND 100 MILES
SOUTHEAST OF GUAM NEAR 13N146E. THIS SYSTEM IS CURRENTLY THE SUBJECT
OF A TROPICAL CYCLONE FORMATION ALERT ISSUED BY THE JOINT TYPHOON
WARNING CENTER UNDER WMO HEADER WTPN21 PGTW. THE DISTURBANCE IS
MOVING WEST AT 16 MPH WITH SURFACE WINDS ESTIMATED NEAR 25 TO 30 MPH
NEAR THE CENTER. THIS SYSTEM COULD BE UPGRADED TO A TROPICAL
DEPRESSION THIS AFTERNOON.

AS THE DISTURBANCE PASSES JUST SOUTH OF GUAM TODAY...EXPECT HEAVY
SHOWERS AND ISOLATED THUNDERSTORMS. WINDS WILL BE AROUND 10 TO 20
MPH WITH HIGHER GUSTS POSSIBLE IN SHOWERS.

EVEN THOUGH THIS IS A TROPICAL DISTURBANCE...RESIDENTS OF THE
MARIANA ISLANDS SHOULD CONTINUE TO MONITOR THE PROGRESS OF THIS
SYSTEM UNTIL THE THREAT HAS PASSED.

STAY TUNED TO NOAA WEATHER RADIO...WHICH IS ALSO AVAILABLE ON GUAM
BY DIALING 811 ON THE TELEPHONE...OR TUNE IN TO LOCAL MEDIA SOURCES
FOR THE LATEST WEATHER INFORMATION. THE NATIONAL WEATHER SERVICE
GUAM WEBSITE IS LOCATED AT HTTP://WWW.PRH.NOAA.GOV/GUAM (LOWER CASE).

PRIOR

Event by event

1 tropical storm. Local standard time, as filed.

Tropical Storm, Guam

When: September 19, 12:00 PM SST to September 21, 12:00 PM SST
Where: Guam forecast zone
Reported by: NWS STORM SURVEY

What these are

Tropical Storm: A tropical cyclone with sustained winds of 34 to 63 knots (39 to 73 mph).

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

The same day elsewhere

Every storm in Guam in 2004 Every state in 2004 This day in weather history Warnings in Guam, September 2004 The 2004 hurricane season

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: 5432268.