439
AXPQ20 PGUM 160107
TWDPQ

Tropical Weather Discussion
National Weather Service Tiyan GU
1107 AM ChST Fri May 16 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...

NEAR EQUATORIAL TROUGH...
A Near Equatorial Trough (NET) enters the region near 5N130E and
extends southeastward through a weak circulation near 3N132E to end
at EQ142E, where models indicate a possible buffer circulation. The
convection extends about 300 miles on either side of the trough axis.
Scattered to numerous showers and isolated thunderstorms are
observed with this feature. The thunderstorms are most notable near
the northern Indonesian islands of Aju, Quoy and Ormsbee reef. The
weak circulation is expected to move out of the region over the next
3 to 4 days, while the NET is expected to remain fairly stationary
and convectively similar over.

TRADE-WIND TROUGHS...
Multiple trade-wind troughs are observed within the general
convergence zone spanning much of Micronesia, which remain difficult
to distinguish from the background trades. The more notable troughs
are embedded in the ITCZ, producing scattered showers and some
thunderstorms across Chuuk and Pohnpei States. These features will
continue to move along the trades to the west, remaining largely
transient in nature.

TUTT...
The Tropical Upper-Tropospheric Trough (TUTT) enters the region near
25N167E and extends southwestward between Minami Torishima and Wake
Island to end near 10N144E southeast of Guam. A thin line of cloud
cover is observed along the northern side of the trough axis. There
are little to no surface features present for the TUTT to interact
with. The TUTT is expected to decay as an upper-level high moves in
to take its place over the next 3 to 4 days.

...ITCZ...
The Inter Tropical Convergence Zone (ITCZ) continues to develop
across central and eastern Micronesia, from 150E to the Date Line
between 7N and 2N. Scattered to numerous showers and isolated
thunderstorms are observed across Chuuk, Pohnpei and Kosrae States
along with RMI. The heaviest showers and thunderstorms are observed
in Chuuk State. The ITCZ is anticipated to continue to fill in over
much of eastern Micronesia over the next 3 or so days. Then, the
southeasterly wind component will begin to break down and enter a
dissipating phase.

...OTHER SYSTEMS...

SQUALL LINE...
A squall line is passing to the west of Iwo To, encountering
frictional forces as it interacts with the subtropical ridge. The
line of thunderstorms are extending about 75 miles on either side of
the squall axis. This squall is expected to dissipate by the end of
the day.

$$

Bowsher