595
AXPQ20 PGUM 112352
TWDPQ

Tropical Weather Discussion
National Weather Service Tiyan GU
952 AM ChST Mon May 12 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,
extending east-southeast across southern portions of Republic of
Palau to a buffer circulation near EQ146E in southeastern Yap State.
Little to no convection is associated with this feature, with
showers and thunderstorms related mostly to the broad surface trough
extending from the aforementioned buffer circulation in eastern Yap
State (more in trade-wind troughs section below). This feature is
expected to remain largely stationary over the next several days, as
the environment will remain favorable for any embedded disturbances
to try to form within the NET in the second half of the week.

TRADE-WIND TROUGHS...
A broad trade-wind trough extends from a buffer circulation near
EQ146E in southeastern Yap State, northward to end near 10N well
south of Guam. Moderate to occasionally deep convection is associated
with this feature as a convergence zone develops just upstream, and
interacting with the NET downstream. This results in scattered to
numerous showers and some thunderstorms across a large area from 140E
to 150E between 10N and the Equator, spanning much of Eastern Yap
State and northwest of Chuuk. Convective activity is supposed to
diminish overnight, followed by another intensification cycle once
the trough further buckles against the NET, forming a region with
deep convection all within the eastern peripheries of the NET. This
is expected to assist in producing a much more favorable environment
for any potential disturbances embedded within the NET to gain
momentum in the second half of the week.

A second, albeit weaker surface trough, extends south-southwest from
Majuro down to the Equator to end just northeast of Nauru. Increased
cloud cover and mostly scattered showers are observed within the
southernmost sector hugging the Equator. This feature is expected to
dissipate overnight as it cross the Equator.

OTHER SYSTEMS...
A squall line extends from 21N133E to 24N135E within the the
northwestern fringes of NWS Guam`s AOR, producing numerous
thunderstorms as it encounters shear against the ridge flow to the
Mei-Yu front to the northwest. This feature is expected to dissipate
as it loses its convective vigor overnight due to forced ridging.

$$

Montvila