133
AXPQ20 PGUM 190032
TWDPQ

Tropical Weather Discussion
National Weather Service Tiyan GU
1032 AM ChST Thu Sep 19 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...

MONSOON TROUGH...
The monsoon trough has weakened and retreated west beyond 130E.

TRADE-WIND TROUGHS...
Three trade-wind troughs are evident across the region. The first one
is seen just east of Yap, extending northward from near 6N140E to
12N140E. Isolated moderate convection is seen north of Yap Proper
associated with the trough. This trough is expected to slowly drift
west over the next couple of days, being slowed by a surface ridge
currently over Palau and Yap State.

The second trough is found south of Guam from 1N143E to 12N145E.
Moderate to deep convection is associated with the trough south of
Guam to well south of Yap. This trough will continue to move west and
due to the slowing effect of a surface ridge over Palau and Yap, it
is likely the first and second trough will merge just east of Yap
Proper.

The third trough extends north from near 7N171E to 15N171E. This
trough is interacting with the ITCZ to enhance the convergence east
of 175E, producing widespread moderate to deep convection. The trough
looks to move west, enhancing the ITCZ as it approaches Kosrae and
Pohnpei over the coming days.

TUTT...
A TUTT cell is centered east of the northern CNMI near 20N150E. A
trough extends northeast from the cell to beyond 25N near 158E.
Another trough extends south from the cell to just east of the
Marianas near 15N147E, continuing south to beyond the equator near
150E. Little convection is associated with the TUTT cell, however,
moderate to deep convection is present along the trough both
northeast and south of the TUTT cell, near Minami Tori Shima to near
Tinian and Saipan to between Chuuk and the Marianas. The TUTT and
TUTT cell look to drift slowly west over the coming days.

OTHER SYSTEMS...
A surface high pressure ridge is in place across Yap and Palau
producing dry conditions across both Yap State and the Republic of
Palau. Bands of convergence to the south, west and north of the ridge
are generating widespread deep convection from south to east to well
north of Palau. This ridge is expected to continue to weaken over the
next couple of days allowing this convection to creep into the
region.

...ITCZ...
The ITCZ stretches east-northeast from northwest of Kosrae near
6N160E to east of Majuro near 8N173E, then turns east to beyond the
Date Line near 6N. A trade-wind trough is seen just east of Majuro
as well, moving along the ITCZ. This feature is helping to enhance
the convergence east of 175E to beyond the Date Line, producing
widespread moderate to deep convection. Otherwise, spotty showers
are seen to the west across Kosrae. The ITCZ is expected to drift
west over the coming days, with increased convection as the
convergence strengthens and surface troughs interact with it.

$$

Kleeschulte