716
AXPQ20 PGUM 200029
TWDPQ

Tropical Weather Discussion
National Weather Service Tiyan GU
1029 AM ChST Thu Nov 20 2025

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...
The NET remains stationary today, extending west-northwest from
EQ150E to 3N130E. Scattered convection continues to develop along
and near this feature, which should persist through the weekend as
little movement or orientation change of the NET is anticipated.

TRADE-WIND TROUGHS...
A trade-wind trough stretches northeast from west of Nukuoro near
4N154E through Pohnpei, ending near 9N158E. Widespread showers,
some heavy, and a few thunderstorms continue to develop near this
feature. The coldest cloud tops have reached an impressive -92C,
indicating cloud tops likely exceeding 60,000 feet tall. This
trough will continue to remain quite active as it heads west the
next several days, eventually interacting with the NET further
west to some extent.

TRADE-WIND SURGE...
Strengthening high pressure east of Japan has allowed the pressure
gradient across the region to tighten. As a result, the trade-wind
surge has expanded and strengthen today. It`s now centered mainly
between 8N and 17N from 150E to the Date Line. The strongest winds
are found near Bikini Atoll (12N165E) and north of there, where
the scatterometer pass showed sustained winds peaking just short
of gale force at 30 knots. This expanding wind field has allowed
maximum sea heights to push 11 feet, with this surge likely
affecting the Marianas to some extent during the next few days.
This surge should maintain similar strength and orientation the
next few days, likely weakening around the weekend or early next
weak, as a changing synoptic pattern allows the gradient to relax
some.

OTHER SYSTEMS...
An upper low remains stationary near 10N151E, north of Chuuk.
However, what the models didn`t show yesterday was a new upper low
that has formed over the Marianas, centered near Pagan. Neither
feature is producing much in the way of convection, with just very
isolated showers observed. Still, given this wasn`t forecast to
occur (The Marianas low development), we`ll keep an eye on things
the next few days as upper low/NET interactions can be interesting
if they get close enough to interact with one another.

...ITCZ...
Today the ITCZ remains unchanged in position, centered between 5N
and 9N, extending from the Date Line to 165E. Upstream (east of
the Date Line), the ITCZ is weaker today and satellite shows
convective coverage is anemic. Thus, the models were likely "over-
playing" the strength and progression of the ITCZ compared to
earlier this week. The models now show the ITCZ becoming
fragmented over the next 48 hours, with the convection associated
with with a trough near Pohnpei forecast to get absorbed by a NET
to the west towards the weekend.

$$

Doll