229
AXPQ20 PGUM 220102
TWDPQ

Tropical Weather Discussion
National Weather Service Tiyan GU
1102 AM ChST Fri Nov 22 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...

TRADE-WIND TROUGHS...
A shallow trade-wind trough is seen just west of Palau, extending
southeast from around 8N132E to around 5N138E. Scattered showers
and isolated thunderstorms are seen across the area near the
trough axis, mainly focused to the southeast of Palau where
surface convergence is stronger. This trough will gradually shift
further west of Palau over the next few days, and showers will
move away with it.

A few sharp trade-wind troughs are seen over east Micronesia
within a fragmented Intertropical Convergence Zone (ITCZ). The
first trough extends northeast from the south of Kosrae near
EQ161E, to the west of Majuro near 8N168E. The second, weaker
trough is located east of the Marshall Islands, extending
northeast from around 3N174E, exiting Guam`s Area of
Responsibility (AOR) near 7N180. Numerous showers and isolated
thunderstorms are seen along the trough axis south and east of
Kosrae, covering much of the central RMI. To the east, showers are
scattered along the second trough axis, becoming numerous near
the Date Line where the trough intersects the ITCZ. These troughs
look to gradually merge into one broad east-west oriented trough
as the ITCZ organizes over the next day or so, shifting slightly
further north and west across the Marshall Islands. A portion of
the trough breaks off and shifts west across Pohnpei and Chuuk
come Sunday, flexing northwest toward the Marianas and increasing
showers across the area through the midweek.

TRADE-WIND SURGE...
Scatterometry data from overnight and this morning show a broad
area of moderate to fresh trade winds east of the Marianas, from
roughly 7N to 17N, and around 155E to 180. Fresh trade winds are
also seen in a narrower band south of the Marianas. Model trends
point to strengthening trade winds across the region over the
next few days, in response to a broad-scale tightening in the
pressure gradient. This moderate trade wind surge looks to extend
westward across the Marianas over the coming days as well, as the
subtropical ridge strengthens north of the islands. The Marianas
will see gradually increasing wind speeds today and tonight, with
moderate to fresh trades expected, maintaining at this level for
much of the weekend. The trade surge will be most felt late Sunday
night through early next week as sustained winds increase
further, exceeding 20 mph at times. This will contribute to
higher, choppier seas, which could potentially become hazardous to
small craft at times next week. Trade winds will gradually relax
by the end of next week as the pressure gradient slackens.

ITCZ...
A fragmented ITCZ enters the AOR at around 8N180, extending west-
southwest across the central Marshall Islands and ending east of
Kosrae near 6N165E. Within this area, scatterometry data this
morning shows generally moderate east-southeast flow near and
south of 7N, and fresh east to east-northeast flow north of
roughly this latitude. Numerous showers and isolated thunderstorms
are seen along the ITCZ near the axis of an embedded trade-wind
trough, spreading across much of the RMI south of Kwajalein Atoll
and north of Ebon Atoll, including over Ailinglaplap, Jaluit, and
Majuro Atolls. Showers are scattered along the ITCZ elsewhere,
over eastern Kosrae State and spanning the area east of the
Marshalls continuing through the Date Line. The ITCZ looks to
continue to organize slightly over the next few days as it extends
westward, bringing showers over Kosrae, Pohnpei, and later Chuuk
this weekend. Early next week, an ITCZ-like fragment looks to flex
northward toward the Marianas as a strong low-pressure system
transits the central North Pacific, bringing showers near the
islands through midweek.

$$

DeCou