299
AXPQ20 PGUM 260043
TWDPQ

Tropical Weather Discussion
National Weather Service Tiyan GU
1043 AM ChST Sun Jul 26 2026

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 93W continues to retain a "Sub-Low" rating from JTWC. It`s
located north of Pohnpei near 11N158E. It continues to be an
asymmetric system, with convection confined to it`s southern
through western flanks, as the system fights 20 to 25 knots of
easterly shear at 200mb. This system is not expected to develop
over the next few days, as it continues west, eventually passing
south of Guam.

...OTHER WEATHER SYSTEMS...

MONSOON TROUGH...
The monsoon trough enters Guam`s AOR at 15N130E and extends
southeast to a developing circulation near Fais and Ulithi, in
western Yap State near 10N140E. It then continues east-northeast
to 93W, turning east-southeast to pass through a col between Ujelang
to Ujae in the FSM. It then continues east through Majuro and
exits Guam`s AOR at 8N180. Similar to yesterday, scattered showers
are found within ~6 degrees (360 miles) of latitude of the trough
axis. Here, scattered to numerous showers and isolated to
scattered thunderstorms are common, with cloud top temperatures
surpassing -70 deg. C fairly often, indicative of some heavy
rainfall. Overall, the trough looks to continue realigning in an
east-west form (in general), modulated locally in orientation by
93W and a strong tropical disturbance just east of the Date Line.

This latter disturbance is already classified as Invest 92C by
CPHC, after coordinating with JTWC. Given the synoptic pattern and
satellite imagery, this latter disturbance is organizing, and it
may become a tropical depression over the next 24 to 48 hours, by
which time it will have crossed the Date Line and into
Guam`s/JTWC`s AORs. Stay Tuned!

SURFACE TROUGHS...
A surface trough continues to extend north from 93W. Today, it`s
aligned with 158E, and ends at 22N. Once you get north of 93W,
convection is pretty spotty (isolated), small, and shallow. As
such, aside from a few brief showers to mariners on the open seas,
it`s not doing much. This trend is expected to continue the next
few days as it heads west.

Another surface trough extends northeast from a broad/weak area
of low pressure near 19N139E, to the northeast as it passes
through the far northern CNMI, exiting Guam`s AOR near 25N151E. A
broken line of cumulus, with embedded shallow-topped showers
(cloud top temperatures struggle to reach -50 deg. C). This trough
is stationary, and as such the showers have little movement,
mainly driven by outflow interactions. This pattern will probably
continue for a couple of more days, possibly longer.

$$

Doll