045
AXPQ20 PGUM 200057
TWDPQ

Tropical Weather Discussion
National Weather Service Tiyan GU
1057 AM ChST Sat Jul 20 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...

TROPICAL CYCLONES...
Tropical Depression 05W has formed and is centered just to the
west the Area of Responsibility (AOR) near 14.5N 129.5E. TD 05W
continues to trek off the northwest through the Philippine Sea and
away from the Marianas and western Micronesia. TD 05W is expected
to strengthen into a tropical storm on Sunday, then turn more to
the north early next week and head towards the East China Sea,
possibly developing into a typhoon.

For more information please refer to bulletins from the Joint
Typhoon Warning Center under WMO header WTPN32 PGTW and from the
National Weather Service under WMO header WTPQ32 PGUM.

...OTHER WEATHER SYSTEMS...

MONSOON TROUGH...
The monsoon trough begins over northern Philippines and extends
through TD 05W and enters the AOR near 15N130E. The monsoon trough
then stretches east to 15N140E and turn southeast and ends near
10N141E, staying north of the main islands of Palau and Yap Proper
and southwest of the Marianas. The trailing west to southwest
monsoon flow stretches over the Republic of Palau and western Yap
State. Pockets of moderate to deep convection are occurring within
the trough and the trailing monsoon flow, generally west of the
Marianas and to the north and west of the main islands of Palau
and Yap Proper.

The monsoon trough is expected to continue to lift north and west
as it is pulled by TD 05W as it heads northwestward into the
Philippine Sea. This will keep Palau and Yap in west to southwest
flow with scattered showers and isolated thunderstorms expected
through the weekend, thought the potential for heavier showers and
thunderstorms will be favored north of both Palau and Yap.

TRADE-WIND TROUGHS...
Multiple trade-wind troughs are passing through the AOR. A notable
trough begin near EQ148E northeast across Chuuk State to 13N154E
east of the Marianas. Pockets of moderate to deep convection
occurring within the trough; one southwest of Weno and another to
the northeast of Weno. The trough will drift west towards the
Marianas, arriving on Sunday and bringing showers and possible
thunderstorms. Another trough has crossed the Date Line and is
approaching the Marshall Islands, stretching from 10N174E
southeast to near EQ180. Pockets of moderate convection are
occurring within this trough. This trough will pass through the
Marshall Islands, bringing scattered to numerous showers through
the weekend.

TUTT...
A Tropical Upper-Tropospheric Trough (TUTT) enters the AOR near
25N168E through a TUTT low centered north of Wake Island and
across the western Marshall Islands to north of Pohnpei. Pockets
of shallow showers are occurring underneath the TUTT. The TUTT
will linger through most of next week. Upper-level divergence
south and east of the TUTT will help enhance convection in
association of a developing Inter-Tropical Convergence Zone (ITCZ)
over the Marshall Islands.

Another TUTT enters the AOR near 25N147E and stretches southwest
through a TUTT low north of the Marianas centered 23N144E, then
west and exiting the AOR near 24N130E. Pockets of showers and
isolated thunderstorms are occurring under the TUTT, especially
near the TUTT low north of the Marianas and southeast of Iwo To
where it interacts with a passing surface trough. This TUTT will
drift south and east through early next week, merging with the
other TUTT east of the Marianas. The TUTT could help enhance
convection with the trough approaching the Marianas Sunday.

...ITCZ...
The ITCZ has weakened and fragmented into a series of troughs
across central and eastern Micronesia. Pockets of moderate
convection stretch across the region in between EQ and 10N, from
eastern Yap State through Chuuk, Pohnpei and Kosrae States and the
Marshall Islands to east of the Date Line. The ITCZ reemerges
east of the Date Line and is expected to redevelop into the AOR
through the weekend and early next week, increasing showers and
thunderstorm potential across eastern Micronesia and the Marshall
Islands.

$$

Slagle