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AXPQ20 PGUM 092208

TWDPQ 



Tropical Weather Discussion

National Weather Service Tiyan GU

808 AM ChST Sat Jun 10 2023



Tropical Weather Discussion for the Western North Pacific between

the Equator and 25N from 130E to 180. The following information is

based on recent satellite imagery/data, weather observations, radar,

and meteorological analysis.



...SIGNIFICANT/SPECIAL FEATURES...



TROPICAL CYCLONES...

Typhoon Guchol (03W) is centered near 18.8N and 129.9E, or about 1050

miles west-northwest of Guam. Torrential rain and isolated

thunderstorms are found between 17N and 20N from 131E to 130E and

farther west. Maximum sustained winds are now 105 mph. Movement last

6 hours was 335 degrees, or north-northwest, at 2 mph.



For more information please refer to bulletins from the Joint

Typhoon Warning Center under WMO header WTPN31 PGTW and from the

National Weather Service under WMO header WTPQ31 PGUM.



...OTHER WEATHER SYSTEMS...



MONSOON TROUGH...

The monsoon trough extends from north of Luzon to Typhoon Guchol near

18.8N and 129.9E to 11N136E. It then continues as a surface trough to

11N141E. Convergence near the monsoon trough is causing moderate

convection south and east of Typhoon Guchol. Within Micronesia, this

is inside an area bounded by a line from 11N130E to 13N137E to 17N137E

to 21N134E to 21N131E to 18N132E to 17N130E then back to 11N130E.

This is north of Palau and Yap and east of the Marianas.



TRADE-WIND TROUGHS...

There are currently 3 trade-wind troughs in Micronesia. The first one

curves from 4N148E to 10N144E to 17N144E to 25N146E. This trough is

causing scattered showers east of the Marianas. The showers north of

16N are occasionally becoming thunderstorms.



The second trade-wind trough runs from EQ154E to 17N153E. This trough

is creating numerous shows and isolated thunderstorms over large areas

of Pohnpei state, especially eastern Pohnpei state.



The last trough stretches from EQ161E to 5N162E to 9N168E. This trough

is spraying scattered showers and isolated thunderstorms over a large

area of the southern Marshall Islands between the equator and 7N from

164E to 172E. This is south of both Majuro and Kwajalein.



TUTT...

The TUTT (Tropical Upper Tropospheric Trough) threads its way from an

upper-level low east of the date line to 19N180 to an upper-level low

near 19N170E to 25N162E. Scattered showers and isolated thunderstorms

are found between 18N and 20N from 165E to 169E, including Wake

Island.



...DISCUSSION...

Typhoon Guchol is near its peak at this time, and it should be

downhill from here. After maintaining its current strength for about

12 more hours, it's expected to begin its slide toward oblivion,

possibly being downgraded to a tropical storm around Tuesday south

of Japan.



The monsoon trough is likely to be dragged northward by Typhoon Guchol

and will therefore have progressively less influence on Micronesia.

Already its influence is rather small, and will grow even smaller.



The trade-wind troughs are expected to move westward with little

change in intensity. This could be the cause of the scattered showers

early next week for the Marianas. The trough near Pohnpei will be

beginning to affect Chuuk, and the one near Kosrae will begin to

affect Pohnpei.



The TUTT is now developing a linkage to a mid-latitude trough which

will likely be its end. This being TUTT season though, it will not

take long for a new one to build in, so we will watch for it.



$$



Stanko