546
AXPQ20 PGUM 080123
TWDPQ

Tropical Weather Discussion
National Weather Service Tiyan GU
1123 AM ChST Tue Jul 8 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...
A monsoon trough extends east from Tropical Storm Danas north of
Taiwan and enters the Area of Responsibility (AOR) 25N130E towards
a developing low southwest of Iwo To, then extending east and
ending southwest of Minami Torishima near 24N153E. Modest west to
southwest monsoon flow is occurring south and west of the trough,
along and west of the Marianas and down across western Yap State.
However, a push of west-southwest winds is working into Republic
of Palau. Within the flow, a surface trough extends south from the
circulation near Iwo To, passing west of the Marianas, then
turning southeast and ending in a col east of Yap Proper near
9N141E. Pockets of moderate to deep convection are occurring
within the monsoon flow, across the Republic of Palau and western
Yap State, then stretching north and east across the Marianas and
up towards Minami Torishima and Iwo To. The active pattern will
continue across the region as the circulation continues to develop
near Iwo To and the west to southwest monsoon like pattern
remains, with a stronger monsoon push into the Republic of Palau.

SURFACE TROUGHS...
A sharp surface trough along the leading edge of the ITCZ begins
near the equator near 172E and extends north-northwest, passing
between Majuro and Kwajalein and ending near 14N168E. Moderate to
deep convection is occurring along this trough across much of the
southern Marshall Islands. Gale-force gusts were measured at
Kwajalein with a convective outflow boundary along the leading
edge of the trough. Another surface trough out ahead of the
aforementioned trough begins south of Kosrae near 4N164E and
stretches north across the island, ending near 12N163E. Pockets of
showers and thunderstorms are occurring along the trough,
including over Kosrae. These troughs will slowly work west-
northwest, with convection increasing across Pohnpei and Kosrae
States, but diminishing over the Marshall Islands.

A weak surface trough extends northwest from the equator near
145E and ends in a col east of Yap Proper near 9N141E. A flare-
up of convection is present along the western edge of the trough
over eastern Yap state, where northeasterly winds are converging
with westerly monsoon flow. This feature will drift west and
dissipate over the next day or so as it runs into increasing
westerly winds.

Another surface trough begins east of Wake Island near 18N172E,
extending north and exiting the AOR near 25N172E. Moderate to deep
convection is occurring along the trough east of Wake Island, with
support from the upper-low to the north and west. This trough will
lift west-northwest across Wake Island over the next 24-36 hours,
eventually merging with the monsoon trough near Minami Torishima
by the weekend.

TUTT...
The TUTT crosses the Date Line at 23N to an upper-level low north
of Wake Island centered near 23N167E, extending south and then
west to a TUTT cell northwest of Weno, Chuuk centered near 9N149E
and then ending southwest of the lagoon near 5N146E. Moderate to
deep convection is occurring east of Wake Island in association
with the approaching surface trough and where upper-level
divergence is enhanced south and east of the upper low. This low
will continue to drift northwest, helping enhance showers and
thundestorms over Wake Island. Spotty pockets of showers are
occurring along the TUTT from southwest of Wake Islands down to
Chuuk State. The TUTT cell north of Weno, Chuuk will slide
southwest and open into a trough, heading towards Yap State and
the Republic of Palau, helping enhance showers and thunderstorms
through the end of the week.

...ITCZ...
The ITCZ begins along a leading-edge surface trough situated in-
between Kwajalein and Majuro near 8N170E, extending east-
southeast across the southern Marshall Islands and crossing the
Date Line near 5N. Moderate to deep convection is occurring along
the ITCZ, especially along the leading trough over much of the
eastern Marshall Islands including Majuro, then spreading south
and east towards the Equator/Date Line intersection. The ITCZ is
expected to expand west across Kosrae and Pohnpei States over the
next couple of days, possibly building into Chuuk State by
Thursday. The ITCZ is expected to diminish across the Marshall
Islands through the week.

$$

Slagle