Tropical Weather Discussion
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AXPQ20 PGUM 130102

Tropical Weather Discussion
National Weather Service Tiyan GU
1102 AM ChST Thu Jun 13 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.




A broad trade-wind trough extends southwest from west of Chuuk
Lagoon from near 9N147E to a buffer circulation near EQ138E.
Scattered showers and isolated thunderstorms are developing along the
axis of the trade-wind trough. The trough is expected to slowly
drift westward towards Yap Proper and Palau, keeping increasing
showers at both locations around Friday. West of the trough and
south of Palau, southwest to westerly winds extend from near the
buffer circulation near EQ138E towards the Philippines beyond 130E.
Scattered showers are developing along the equator within the
westerly winds.

The primary upper-level low has drifted west-southwest and is now
located near 17N153E, between the Marianas and Wake Island.
Convection is still largely non-existent near the low, however a few
showers and thunderstorms are found farther to the southeast and
toward the northern Marshall Islands just south of the TUTT axis that
curves from across the Date Line at 17N180 to 12N165E to the TUTT
low. Another trough extends southwest from the low and ends south-
southeast of Guam near 12N145E, but convection along this trough axis
is limited. This low will slowly head westward toward the Marianas
by this weekend. Its presence may help to enhance some thunderstorms,
especially just south of the TUTT axis.


The ITCZ has developed across eastern Micronesia extending westward
from beyond the Date line, extending across the Marshall Islands,
Kosrae, Pohnpei and into Chuuk where it then interacts with a trough
moving into eastern Yap State near 147E. Scatterometer shows
southeast trade winds around 10 to 15 kt near and south of 5N, with
the bulk of the convergence between the northeast and southeast trade
winds around 5N to 7N. Most numerous showers and isolated to
scattered thunderstorms are developing along the trade convergence
or within the southeast flow, with the exception of the convection in
the Marshall Islands where showers extend from near Kwajalein near
8N and up to north of Bikini and Rongelap atolls, ending near 13N.
This is due to the upper-level support from the TUTT discussed above.
The ITCZ will continue to affect the region over the next few days
with some minor shifts to the north and south.