542
AXPQ20 PGUM 030127
TWDPQ

Tropical Weather Discussion
National Weather Service Tiyan GU
1127 AM ChST Wed Sep 3 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...

None.

...OTHER WEATHER SYSTEMS...

MONSOON TROUGH...
Invest 95W has moved back into Guam`s AOR and is currently located
at 24N132.9E, which is south of Minami Dalto Jima based on the
latest visible satellite analysis. A monsoon trough extends
northeast from this low-level circulation center, exiting Guam`s
AOR at 25N138E. A south to southwest monsoon flow is responsible
for abundant cloud cover, widespread showers, and scattered
thunderstorms north of a line from 13N130E to 25N138E. 95W is
currently moving northeast, with a turn to the north and then
northwest expected over the next 24 hours as it passes very near
to Minami Dalto Jima This will eventually drag all associated
weather with 95W out of Guam`s AOR in the next 24 to 48 hours.

TRADE-WIND TROUGHS...
The first in a series of troughs in the trades extends from east
of Palau, through Yap, to just west of the Marianas. This feature,
similar to the past several days, remains convectively active with
widespread cloud cover, numerous shower, and scattered
thunderstorm development. This will continue to be the case for
the remainder of this week as it continues on its westward
journey.

Farther east, the next trough is located northwest of Chuuk to
east of the Marianas (10N150E to 16N152E)This feature has
amplified since yesterday and looks to bring a continued wet
weather pattern to the Guam and the southern half of the CNMI as
it heads west the next several days, mainly affecting areas of
open water this week after passing the Marianas.

East of there is a trough stretching from Kapingamarangi of
Pohnpei through Pohnpei, to just west and north of Enewetak in
the FSM. This trough shows up decently in the streamline analysis,
but the southern portion south of Pohnpei was added to this based
on the latest MIMIC water vapor imagery, showing an increase to
just shy of 2.5 inches present along this axis, flanked by drier
air on both sides. This feature is forecast to strengthen some
over the next 24 to 48 hours as it heads west, possibly becoming
more convectively active. The trough will continue to affect
portions of western and eastern Micronesia for the remainder of
this week.

A fourth trough stretches from east of Kosrae through Kwajalein,
to between Wotje and Taongi in the RMI (14N169E). Scattered
showers continue to develop, and given the amount of moisture
associated with it in the MIMIC imagery, a thunderstorm or two
can`t be ruled out from developing today as well. This theme
continues for the remainder of this week as it heads west through
portions of Micronesia.

Finally, A trough stretches from Makin in the southern RMI to
13N180. This feature also has scattered to locally numerous
showers, with a few thunderstorms also developing. This will
continue to be the case this week as it continues to cross eastern
Micronesia and the RMI.

TUTT...
Today`s TUTT resembles a snake, as it stretches in wavy form from
25N180 where it enters Guam`s AOR, to Wake Island where a cell is
located, then to another cell at 19N154E, to a new cell forming
west of Pagan in the northern CNMI, with the TUTT axis stretching
across at Guam.

The TUTT will continue to strengthen and elongate to the west
through the weekend, with convection more plentiful near the cells
and along its southern axis where ascent is boosted, occasionally
interacting with surface troughs in the flow, helping to fuel at
least scattered shower development. By the weekend, the western
extent of the TUTT will extend from the northern CNMI to near
130E.

...ITCZ...
The ITCZ remains convectively-void across the region, with the
exception being near any surface trough, which is more directly
responsible for the convection. The latest numerical forecasts
continue to show the lack of a coherent/focused ITCZ developing
during the remainder of this week, with the troughs continuing to
be the main driver of convective development.

$$

Doll