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AXPQ20 PGUM 080042
TWDPQ

Tropical Weather Discussion
National Weather Service Tiyan GU
1042 AM ChST Wed Jan 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...

NEAR EQUATORIAL TROUGH...
A near-equatorial trough runs from 8N130E to just south of Koror at
7N135E to EQ152E. Isolated to scattered showers in the west end of
the trough, scattered to numerous heavy showers in the east end of
the trough, and isolated thunderstorms throughout have been observed
north of the trough axis. This feature has expanded northward and
eastward. The bulk of the showers are south of Chuuk and Pohnpei, and
over Kapingamarangi. These showers are rather robust and afair
amount of lightning has been observed. This system is expected to
begin contracting again over the next couple of days, with little
change of intensity.

TRADE-WIND TROUGHS...
A trade-wind trough is shown to be pushing into a shear line is
located due west of the Mariana Islands chain, the north end point
is near 19N146E and the south end point is near 11N137E (north of
Yap Proper). The showers have been diminishing over the past several
hours and is expected to dissipate over the next day or so.

OTHER SYSTEMS...
Two shear lines are evident on satellite imagery. The first one is
near 13N180 and heads southwest to about 12N153E (south of
Chuuk). This shear line is fairly weak and cloud cover and showers
are expected to be minimal, most notably on the northern side.
Little change is expected for the next few days.

The second and more robust shear line is near 25N158E and bows
southwesterly to about 13N130E. Patchy showers and extensive low and
mid level clouds are found along and north of this boundary to 25N
and beyond. Winds north of the shear line have been in the 20 to 25
knot range according to the overnight ASCAT pass. The shear line is
expected to show little movement with little change of intensity over
the next few days.

A notable high pressure system in the mid latitudes is causing
higher seas north of Wake Island. Seas of 10 to 14 feet have been
shown by altimetry passes over night. These large seas are expected
to gradually move south and east over the coming days as the high
pressure system moves eastward.

$$

Bowsher