120
AXPQ20 PGUM 050111
TWDPQ

Tropical Weather Discussion
National Weather Service Tiyan GU
1111 AM ChST Sat Apr 5 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 a weak
circulation southeast of the Philippines, entering the region near
4N130E and ends near EQ135E. Most of the of the moderate to heavy
showers and thunderstorms associated with the NET are west of 130E
but a line of showers and thunderstorms extend into the region along
6N and end near 134E, southwest of Koror. The NET is expected to
shift westward and exit the region Sunday, but models show a new NET
developing south of Palau and Yap early next week.

TRADE-WIND TROUGHS...
There are a couple discernible trade-wind troughs moving across the
region. The first is just west of Yap Proper, extending from 11N136E
to about 7N136E, east of Koror. Cloud cover and showers are fairly
patchy along this trough, but could see some scattered showers and
isolated thunderstorms develop around Palau today as this trough
passes through or just north of Palau and then pushes west of 130E
Sunday.

The second trade-wind trough is more noticeable as it passes well
south of Guam, extending from 10N143E to 3N147E. This trough is
producing scattered showers and isolated showers around Faraulep,
Woleai and other nearby islands. This trough is expected to continue
into western Yap State and potentially passing near Yap and Palau
early next week.

TRADE-WIND SURGE...
New scatterometer data coming in this morning shows the trade-wind
surge extends from Wake Island, near 19N164E to beyond the Date Line,
between 15N and 25N. Showers within the trade wind surge are fairly
shallow and spotty, but along the leading edge of the surge, just
south of Wake Island, the Global Lightning Detection (GLD) network
has detected a few thunderstorms. This trade-wind surge is expected
to continue the next few days as the subtropical ridge is not
expected to weaken or move until the middle of the upcoming week.

OTHER SYSTEMS...
A weakening cold front crosses into the region near 25N154E,
extending southwest to near 19N140E, where it continues as a shear
line to beyond 130E near 14N. Scattered to numerous showers and
scattered thunderstorms are seen along the cold front north of 20N,
with patchy clouds and showers found along the shear line. The shear
line looks to remain quasi-stationary over the coming days while the
cold front continues to move east. Both features look to weaken, with
decreasing convection expected along the cold front.

A band of trade-wind convergence is seen over Micronesia, stretching
east-northeast from near 3N146E to the Date Line near 12N. Scattered
to numerous showers and isolated thunderstorms are present along the
band of convergence between 4N and 10N, across the states of Chuuk,
Pohnpei and Kosrae, and between 5N and 13N across the Marshall
Islands. Enhanced convection seen where trade-wind troughs are
interacting with the convergence, but also across the northern
Marshall Islands near and north of Wotje, where an upper-level
trough has dropped into the region from the mid-latitudes. This
feature looks to remain relatively unchanged through the rest of the
weekend, but may start to weaken and fragment as the upper-level
trough near the Marshall Islands pushes eastward, weakening some of
the upper- level divergence helping to support some of the deeper
convection.

$$

Schank