660
AXPQ20 PGUM 260125
TWDPQ

Tropical Weather Discussion
National Weather Service Tiyan GU
Issued by National Weather Service Honolulu HI
1125 AM ChST Thu Jun 26 2025

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.

...SPECIAL FEATURES...

TROPICAL AND MONSOON DISTURBANCES...
Invest 97W, currently rated a sub-low by the Joint Typhoon Warning
Center (JTWC), is centered near 13N142E. Moderate to deep
convection is occurring near the center and to the north and east
where convergent southwesterly and southeasterly flow meet,
including over the Marianas. Uncertainty in the track and
development of Invest 97W still persists, but the general forecast
trend is for 97W to slowly develop and strengthen near to just
west of the Marianas and slowly drifting away from the islands
through the weekend.

...OTHER WEATHER SYSTEMS...

MONSOON TROUGH...
The monsoon trough extends across the northern Philippines, passing
through 20N130E to a weak circulation near 20N132E, then curving
southeastward through a circulation west of Guam (Invest 97W) near
13N142E, then passing south of Guam and ending in a col west of
Weno, Chuuk near 7N146E. Modest monsoon flow is observed south and
west of the trough axis across the Republic of Palau and Yap
state. Pockets of moderate to deep convection are occurring along
and east of the monsoon trough axis within the convergent flow,
especially from west of the Marianas near Invest 97W and spreading
east over the Marianas. Within the monsoon flow itself are
pockets of moderate to deep convection. One complex is pushing
across Yap Proper, while another complex is straddling 130E to the
west of the main islands of Palau. The monsoon trough is expected
to linger, with the monsoon flow increasing over the coming days
as a 97W slowly develops near to west of Guam and the CNMI into
the weekend.

SURFACE TROUGHS...
A surface trough extends from the monsoon trough, beginning near
18N130E and passing through the weak circulation near 20N132E and
extending northeast, ending near 25N136E. Pockets of moderate
convection are occurring along and east of the trough axis within
the convergent SE flow, mainly over the open waters well north of
the Republic of Palau and Yap state and to the west of Iwo To
Island. This trough will drift west and weaken through the end of
the work week.

Another surface trough extends from the col west of Weno, Chuuk
near 7N146E southeastward across the the lagoon to a weak
circulation near 5N153E where the ITCZ begins. Only spotty showers
are seen withing the trough. This trough is expected to slide
south and west between the developing monsoon flow to the west and
weakening ITCZ pattern to the east, washing out by the weekend as
a surface ridge builds in.

...ITCZ...
The ITCZ begins near a weak circulation southeast of Weno, Chuuk
near 5N153E and extends eastward, passing over Pohnpei and Kosrae
islands, south of Majuro and across the Date Line near 6N.
Moderate to deep convection is observed along and south of ITCZ,
in a boxed area from equator to 7N and 150E to the Date Line,
including over Pohnpei and Kosrae islands, but south of Weno,
Chuuk and Majuro. The ITCZ is expected to dissipate by the end of
the work week, possibly re-establishing itself by late weekend
into early next week.

$$

Slagle