287
AXPQ20 PGUM 012017
TWDPQ

Tropical Weather Discussion
National Weather Service Tiyan GU
617 AM ChST Thu May 2 2024

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 spans across far western Micronesia,
extending from 4N130E to EQ139E, well south of the main islands of
Palau and Yap. Yesterday`s ASCAT analysis showed a very weak
circulation embedded in the NET, however, a circulation center was
difficult to discern in satellite imagery overnight. Widespread
cloudiness, disorganized clusters of showers, and a few
thunderstorms are found along the NET. Moderate, low-level
convergence in the northern peripheries is also generating patchier
showers across Palau and Yap.

TRADE-WIND TROUGHS...
Scatterometry data shows the axis of a weak surface trough pushing
west of the Marianas. Low-level convergence trailing behind this is
generating patchy showers, mainly across the CNMI. Another weak
surface trough is generating an area of patchy showers east of the
Marianas, near 154E. Scatterometry data also captures a pair of
troughs upstream of the NET. Moderate to deep convection is found in
parts of eastern Yap State, but the bulk of activity extends south
to the equator. In central and eastern Micronesia, surges in the
trade flow interact with a surface trough southeast of Chuuk coastal
waters and with a broader trough between Pohnpei and Kosrae. This
continues to bring about enhanced convection, most notably south of
Pohnpei and across Kosrae.

...ITCZ...
The trade-convergence has a more notable, cross-equatorial component
over the past 24 hours and is now considered an ITCZ feature. The
leading edge can be seen near Kapingamarangi, meandering eastward to
an embedded trough near Kosrae and crossing the Date line near 2N.
Throughout this feature, a condensed area of widespread cloudiness
and invigorated convection are found south of Pohnpei, spanning
across Kosrae to about 170E, where the surface trough, trade-surge,
and upper-level speed divergence is further supporting shower
development. Patchy showers are found elsewhere along this boundary,
mainly southern Marshalls and across country lines into Kiribati,
south of 5N.

...DISCUSSION...
A fairly busy pattern remains in store for most of Micronesia. The
trade-wind troughs will continue to push west across the region. The
NET remains pinned in far western Micronesia through the weekend,
with transient troughs moving through the northern peripheries.
Keeping an eye on a possible disturbance forming within the NET
early next week. This is a climatological pattern favored for the
month of May, however, more model consensus is needed to aid in the
certainty of this outcome. So far, models hint at a weak circulation
forming, with the GFS as the outlier, dragging this circulation
northward across Palau. Farther east, the ITCZ is expected to become
more fragmented in the next day or two, losing out on the cross-
equatorial flow as well.

$$

IC