536
AXPQ20 PGUM 050127
TWDPQ

Tropical Weather Discussion
National Weather Service Tiyan GU
1127 AM ChST Sun Oct 5 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 CYCLONES...
Tropical Depression Halong (28W), formerly Invest 94W, developed well
north of the Marianas overnight and is currently located near 25N142E,
east of Iwo To. TD Halong has maximum sustained winds around 35 mph
and is moving west-northwest at around 8 mph. TD Halong is expected to
intensify through Tuesday, likely becoming a tropical storm later
today. Visible satellite imagery shows heavy showers and
thunderstorms displaced slightly east of the center of TD Halong due
to weak westerly shear. Combined seas are around 17 feet near the
center of TD Halong. TD Halong is expected to continue to drift
west-northwest, remaining near or just north of 25N over the next
couple of days. No direct impacts are expected for the main islands
of the Marianas or Micronesia from TD Halong, though the Marianas and
western Micronesia may see a slightly elevated northerly swell late
this week, generated by Halong as it continues to strengthen.

For more information please refer to bulletins from the Joint
Typhoon Warning Center under WMO header WTPN32 PGTW and from the
National Weather Service under WMO header WTPQ32 PGUM.

TROPICAL AND MONSOON DISTURBANCES...
The Joint Typhoon Warning Center (JTWC) has opened Invest 95W on a
broad disturbance located across Chuuk State, centered near 7N153E.
This morning`s scatterometer data does not show a well-defined
circulation, but a broad area of turning, with the CIMSS 850-500 mb
analysis showing a broad area of mid-level vorticity, with the
center displaced slightly northward closer to 11N153E. Given Invest
95W`s current disorganized state, the potential for development into
a tropical cyclone over the next 24 hours is currently very low.
Invest 95W is generating scattered to numerous showers and isolated
thunderstorms across Chuuk State, with pockets of 25 kt (~28 mph)
winds, likely convectively driven gusts produced by heavier showers
and thunderstorms. Further west, some scattered showers are
developing south of the Marianas, along convergent flow along the
western edge of the disturbance. Model guidance suggest Invest 95W
will lift northwest and pass near the Marianas the next few days,
with only some minor development as models struggle to develop Invest
95W as it moves northwest of the Marianas. This will increase
showers, thunderstorms and winds across the Marianas, while also
helping to build southwest flow across Yap and Palau, increasing the
potential for showers and thunderstorms across both locations as
well.

...OTHER WEATHER SYSTEMS...

TRADE-WIND AND SURFACE TROUGHS...
A broad surface trough extends south-southwest from TD Halong and
ends just west of Palau near 6N131E, producing light west to
southwest winds over Palau and Yap. Convection along the trough is
fairly spotty, as the trough sits under a mid-level ridge, this is
helping to suppress showers and thunderstorm development. As TD
Halong drifts west- northwest, this trough is expected to lift
northwest from Palau and Yap.

A weak trade-wind trough is slowly drifting westward, located west
of Wake Island near 18N162E. This trough is producing spotty to
scattered showers near the center of the trough. This trough is
expected to continue to drift westward, potentially dissipating over
the next couple of days.

TUTT...
Water vapor satellite imagery shows only one main TUTT within the
region. This TUTT enters the region near 25N168E, extending
southwest to a cell centered near 15N157E, north of Pohnpei and
southwest of Wake Island, and ends near 10N152E. Divergence
associated with the TUTT and TUTT cell are helping to generating
scattered to numerous showers and isolated thunderstorms along the
northern edge of Invest 95W, located in Chuuk State. The TUTT and
TUTT cell will continue to slowly drift west with little change in
intensity.

...ITCZ...
A strengthening ITCZ is found from north of Kosrae near 7N164E and
extends eastward across the Marshall Islands to beyond the Date Line
near 7N. Convection is fragmented from Majuro to Kosrae, with spotty
to scattered showers across most of the Marshall Islands and Kosrae,
while scattered to numerous showers and isolated thunderstorms are
located west of Majuro and continuing to the Date Line. The ITCZ
looks to meander north and south with models showing convection
fragmenting along the ITCZ over the next couple of days.

$$

Schank