079
AXPQ20 PGUM 030109
TWDPQ

Tropical Weather Discussion
National Weather Service Tiyan GU
1109 AM ChST Thu Apr 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...

NEAR EQUATORIAL TROUGH...
A Near-Equatorial Trough (NET) extends southeast from the far
southern Philippines, passing through a weak buffer circulation
centered near 2N130E where it first enters Guam`s Area of
Responsibility (AOR). The NET then curves east-southeast, extending
over the far outer Indonesian islands before crossing the Equator at
around 135E. Numerous showers are seen along the NET axis and
within the buffer circulation, extending from south of Mindanao
across the southwest corner of the AOR, covering Pulau Fani, Helen`s
Reef, and eastward to Pulau Bras. Showers extend northward to around
Sonsorol, where they become scattered in coverage. The NET and
buffer circulation will make a very gradual westward shift through
the rest of the week, maintaining convection over the area through at
least the start of the weekend.

TRADE-WIND TROUGHS...
Several trade-wind troughs are seen across the region. The first of
these is located just west of the Marianas, extending south-southeast
from 19N141E to just west of Guam around 14N143E. A disorganized
band of isolated to scattered showers is seen just east of the trough
axis, extending over Saipan and Tinian coastal waters, with most of
the showers located west of the northern CNMI. A second, weaker
trough is seen east of the CNMI extending south-southeast from
20N147E to near 14N150E, with patchy showers and cloud cover along
its axis. These troughs and associated showers will continue to
shift west and dissipate over the next day or so.

Another trough is seen south of the Marianas, extending west-
southwest from around 10N150E to around 5N142E. Abundant middle and
upper-level clouds cover the region from prior convection, and
scattered showers are seen extending roughly along the trough axis in
a broad area including Gaferut, Eauripik, and Satawal. Scattered
showers are also seen within the convergent flow just upstream of the
trough, near southwest of Weno, Chuuk. This feature will continue
westward over the next day or so, increasing showers near Yap Proper
and over the Republic of Palau as it gradually merges with the NET
through the end of the week.

TRADE-WIND SURGE...
Scatterometry reveals a broad area of fresh to strong trade winds
across the region mainly north of eastern Micronesia and east of the
CNMI, extending from around 150E to 175E, and from 5N to around 25N.
Himawari visible satellite reveals areas of patchy showers and cloud
cover within this region east of the CNMI, associated with weak,
localized trade-wind convergence. The trade-wind surge will remain
fairly consistent in areal coverage and strength over the next day or
so, followed by a weakening trend this weekend into early next week.

OTHER SYSTEMS...
An Intertropical Convergence Zone (ITCZ)-like boundary is seen
extending west from the Date Line near 5N, crossing the southern
Marshall Islands to end just south of Kosrae around 4N164E. Numerous
showers and isolated thunderstorms are seen across the area south of
Majuro, mainly focused within an embedded trough just southwest of
Jaluit and Namorik Atolls. Another, similar convergence boundary is
seen further north as the remnants of a broad shear line, spreading
scattered to numerous showers over Pohnpei eastward to just over the
central RMI west of Kwajalein. These features will gradually
consolidate northward over the next day or so, spreading showers
over the northern half of the RMI and maintaining showers near Kosrae
and Pohnpei, before shifting west over Chuuk and Yap States this
weekend, as a disorganized, fragmented convergence boundary.

A cold front extends southwestward into the AOR, passing just west
of Iwo To near 25N140E, becoming a shear line around 20N135E. The
shear line then continues southwest toward the Philippines, exiting
the area at 15N130E. Rain and cloud cover extend along and north of
the cold front, becoming patchy showers along and north of the shear
line fragment. The cold front, associated with low pressure just east
of Hokkaido, will continue eastward across the north central Pacific
over the next few days, while the shear line remains quasi-
stationary, gradually dissipating by this weekend.

$$

DeCou