098
AXPQ20 PGUM 130109
TWDPQ

Tropical Weather Discussion
National Weather Service Tiyan GU
1109 AM ChST Thu Nov 13 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...
The circulation, Invest 91W, that was centered well SE of Palau near
3N142E has shifted west and weakened. As a result, the JTWC has
closed Invest 91W. A remnant circulation is found within the Near-
Equatorial Trough near 4N134E. This broader feature will be discussed
more fully, below. This area is not expected to lead to any
formative disturbance in the coming days.

...OTHER WEATHER SYSTEMS...

NEAR-EQUATORIAL TROUGH...
The NET, a familiar feature in the Dec-Apr dry season time frame,
has set up south of Palau and drops ESE through 7N130E to near
1N148E. A weak circulation, the remnants of 91W, is found near
4N134E, just south of Koror. Showers and thunderstorms have largely
decreased along and north of the NET, though heavy showers with gusty
winds of 30-35 MPH are seen south of the NET down to the EQ west of
142E. This feature will be nearly stationary the next several days,
nudging slightly north or south. Showers and thunderstorms will
occasionally spread over Palau as easterly winds converge north of
the NET axis.

TRADE-WIND TROUGHS...
The first trough is currently passing 150E, just east of the Marianas,
and stretches northward from 8N to 15N. Overnight scatterometry data
indicate 15-20 MPH winds, with visible satellite imagery showing
patchy showers and shallow cloudiness present near the westward-
moving trough. As the trough passes the Marianas, winds and cloud
cover will increase slightly tonight and Friday with little notable
change in shower coverage.

Another trade-wind trough near Majuro, while convectively quiet, is
more notable in the low-level wind flow of 10-15 MPH winds. While
this trough will continue west with little fanfare, its westward
march could precede a temporary re-invigoration of ITCZ convection in
the region over the next few days.

TUTT...
The TUTT descends SW through 22N180 through an upper low at 16N176E
to the central Marshalls near 8N161E. With the lack of notable low-
level features, the TUTT, and locally-favorable conditions aloft, are
providing little support to enhance convection. In the coming days,
the TUTT will reorient east to west along 12N, eventually breaking
off into a cutoff upper low. Until then, the TUTT will largely have
minimal impact other than to provide slightly-improved upper-level
divergence to the ITCZ.

UPPER-LEVEL ANTICYCLONE...
A broad upper-level anticyclone is centered NW of the Marianas near
19N140E. This high pressure feature and ENE-extending ridge axis are
fostering a regional subsident flow that is helping to reduce mid and
upper-level moisture in the troposphere. In VIS and IR satellite
imagery, this is noted in a significant decrease in deep convective
development and cirrus clouds.

...ITCZ...
As noted above, the ITCZ is currently rather inert. Showers and
thunderstorms are found along a trade convergence axis between Chuuk
and Pohnpei while clearer conditions are presently seen farther east
with 10-15 MPH winds. A westward moving trough over the Marshalls
will precede the temporary redevelopment of more widespread showers
and thunderstorms along the ITCZ from Chuuk eastward between 4N and
8N for the next few days.

$$

Aydlett