Tropical Storm in Guam, September 29 to 30, 2009

Name: Tropical Storm in Guam, September 29 to 30, 2009
Start: 2009-09-29T12:00
End: 2009-09-30T16:00
Location: Guam

September 29 to 30, 2009 · NWS GUM · 1 event in 1 county or zone

The toll

Deaths: 0
Injuries: 0
Property damage: $10,000
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 GUM wrote it up.

Tropical Depression 19W developed about 250 miles south of Guam early on the morning of September 28th, and intensified into Tropical Storm Parma late that evening as it moved west about 120 miles east of Fais Island in Yap State. After giving Fais a brief brush with minimal tropical storm conditions on the morning of the 29th, Parma turned west-southwest, passing about 100 miles south of Yap that evening. Parma then turned west-northwest again and passed directly over the island of Ngulu about 0500 GST the morning of the 30th with maximum sustained winds of 60 to 65 mph. By 1900 GST that evening, Parma had moved quickly away, and was in the Philippine Sea 250 miles northwest of Ngulu.

The only island to sustain any significant damage was Ngulu, where winds estimated at 60 to 65 mph were experienced. The roof of the community center was damaged by a fallen breadfruit tree, and four homes were damaged; mainly the thatched roofs. No crops were damaged, but about 40% of the banana and papaya trees sustained some damage. Total damage to buildings is estimated at $10,000.

Apart from Ngulu, the only wind information available is from Yap, where the airport recorded a maximum gust of 39 mph at 0608 GST on the 30th.

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 Guam wrote its last area forecast discussion before the first event at Sep 28, 8:21 PM UTC, 5 hours 39 minutes earlier.

Area forecast discussion, Sep 28, 8:21 PM UTC, 5 hours 39 minutes before

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TIYAN GU
621 AM CHST TUE SEP 29 2009

.SYNOPSIS...
PGUA WSR-88D SHOWS ISOLATED SHOWERS MOVING THROUGH THE MARIANAS
WATERS. TROPICAL DEPRESSION 18W IS TO OUR SOUTHEAST WHILE
TROPICAL STORM 19W IS TO OUR SOUTHWEST. AT THE MOMENT THE
MARIANAS ARE CAUGHT IN SOME WEAK PERIPHERAL RIDGING BETWEEN THE
TWO.

&&

.DISCUSSION...
AS THE MONSOON TROUGH CONTINUES TO STAY SOUTH...THE NEXT FEW DAYS
ARE BEGINNING TO LOOK LESS AND LESS RISKY. NOBODY WHO LIVES IN
THE MARIANAS IS COMPLAINING ABOUT THAT OF COURSE. THE TROUGH MAY
START TO EASE ITS WAY NORTHWARD DURING THE LATTER HALF OF THE
WEEK. RAN THE CYCLONE GRIDS AND USED THEM TO RECALCULATE ALL THE
OTHER WIND DEPENDENT GRIDS.

&&

.TROPICAL SYSTEMS...
LIKE PEARLS ON A NECKLACE...SO ARE THE TROPICAL CYCLONES OF THE
WEST PACIFIC RIGHT NOW. THE MONSOON TROUGH CONNECTS THEM ALL JUST
LIKE A STRING. TYPHOON KETSANA IS SOON TO MAKE LANDFALL. THE
TROUGH MEANDERS FROM HERE TO TROPICAL STORM 19W NEAR YAP...THEN
TO TROPICAL DEPRESSION 18W A LITTLE NORTH OF CHUUK AND FINALLY TO
FAIR INVEST AREA 90W A LITTLE NORTH OF KOSRAE. THE MOST WORRISOME
OF THESE IS PROBABLY INVEST AREA 90W. WHILE IT IS THE MOST POORLY
ORGANIZED THIS IS ONLY BECAUSE IT HAS HAD LESS TIME TO DEVELOP.
SEVERAL HOURS AGO THE KOSRAE HANDAR REPORTED 30 KNOT SUSTAINED
WINDS WITH GUSTS TO 40 KNOTS. THE ORGANIZATION SEEMS TO HAVE
INCREASED SINCE THEN...JUST THAT THE CENTER HAS MOVED AWAY FROM
KOSRAE. SINCE WE WOULD EXPECT THE WINDS TO EITHER STAY THE SAME
OR INCREASE...FAVORED THE ECMWF-HIRES SOLUTION IN THE GRIDS.
THESE BROUGHT 25 TO 30 KNOTS WINDS INTO THE MARIANAS AROUND
SATURDAY. THE TIMING OF THE GFS40 IS A LITTLE LATER WHICH MAY
HAVE BEEN PREFERABLE. UNFORTUNATELY WHEN THE CIRCULATION CAME
THROUGH IT WAS ONLY ABOUT 10 KNOTS AND IT SEEMED UNLIKELY FOR IT
TO WEAKEN.

&&

.EASTERN MICRONESIA...
LATEST SATELLITE IMAGERY SHOWS WIDESPREAD SHOWER AND THUNDERSTORM
ACTIVITY ASSOCIATED WITH INVEST 90W...WHICH HAS BEEN UPGRADED TO
A FAIR AREA BY JTWC. SATELLITE LOOP SHOWS A VERY SYMMETRIC AND
PERSISTENT AREA OF INTENSE CONVECTION WITH 90W...WOULD NOT BE
SURPRISED IF THIS SYSTEM BECOMES A DEPRESSION IN THE NEXT SIX
HOURS OR SO...AND A TROPICAL STORM WITHIN 24 HOURS. THAT
SAID...EXPECT HEAVY RAIN AND GUSTY WINDS FOR KOSRAE TODAY AND
POSSIBLY TONIGHT. ON THE CURRENT TRACK...THIS ACTIVITY WILL
SPREAD INTO POHNPEI LATER TODAY. HAVE ACCORDINGLY INCLUDED HEAVY
SHOWER WORDING WITH GUSTS TO 40 KT IN SHOWERS FOR POHNPEI AND
KOSRAE FOR TODAY AND TONIGHT. MAJURO WILL REMAIN IN EASTERLY
TRADE FLOW. SO HAVE FORECAST SEASONAL WEATHER CONDITIONS THERE.

&&

.WESTERN MICRONESIA...
HAVE UPGRADED YAP TO A TROPICAL STORM WARNING. TROPICAL STORM 19W
CONTINUES TO BEAR DOWN ON THE STATE AND WILL PASS OVER THE ISLAND
LATER TODAY. CURRENT IR LOOP SUGGESTS THAT 19W IS BECOMING BETTER
ORGANIZED SO THE PROSPECTS OF THIS SYSTEM PASSING OVER YAP AS A
STRONG TROPICAL STORM ARE VERY GOOD. ACCORDINGLY...HAVE MENTIONED
HEAVY RAINFALL AND 50 KT IN THE FORECAST. ONCOMING SHIFT SHOULD
MONITOR 19W CLOSELY...AS FORECAST WINDS MAY NEED TO BE BUMPED
HIGHER LATER THIS MORNING. DEVELOPING MONSOONAL BANDS SOUTH AND
WEST OF 19W WILL BRING HEAVY SHOWERS AND GUSTS TO 35 KTS TO KOROR
AS WELL TODAY AND TONIGHT.

FOR CHUUK...TROPICAL DEPRESSION 18W WILL CONTINUE WESTWARD WITH
CHUUK JUST INSIDE THE CDO FOOTPRINT. HAVING SAID THAT...IT
APPEARS THAT CHUUK HAS APPEARED TO AVOID MOST OF THE HEAVIER
SHOWER ACTIVITY AND GUSTY WINDS. FARTHER WEST THOUGH...ULUL WILL
EXPERIENCE DETERIORATING WEATHER CONDITIONS LATER THIS AFTERNOON
IF 18W MAINTAINS ITS WESTWARD TRACK. ONCOMING SHIFT SHOULD
CONSIDER WHETHER ADJUSTMENTS ARE NEEDED TO THE SPS LATER THIS
MORNING.

&&

.GUM WATCHES/WARNINGS/ADVISORIES...
GU...TROPICAL STORM WATCH FOR GUZ001-002.

MARIANAS WATERS...TROPICAL STORM WATCH FOR PMZ151-152.

     SMALL CRAFT ADVISORY UNTIL 6 PM CHST WEDNESDAY FOR PMZ153-154.

&&

STANKO/MUNDELL/LEE

Event by event

1 tropical storm. Local standard time, as filed.

Tropical Storm, Micronesia

When: September 29, 12:00 PM GST to September 30, 4:00 PM GST
Where: Micronesia forecast zone
Property damage: $10,000
Reported by: Emergency Manager

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 2009 Every state in 2009 This day in weather history Warnings in Guam, September 2009 The 2009 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: 198187.