851
AXPQ20 PGUM 260102
TWDPQ

Tropical Weather Discussion
National Weather Service Tiyan GU
1102 AM ChST Sat Jul 26 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...

TROPICAL CYCLONES...
Tropical Storm Krosa (12W) is now centered near 17.8N 143.7E, or
roughly 230 miles northwest of Saipan. Krosa has remained quasi-
stationary while the center has repositioned a little farther south.
Krosa looks to gradually strengthen as it makes a turn toward the
north-northeast, then back north over the next couple of days, with
an increase in forward speed. Convection associated with Krosa is
very asymmetrical, with widespread showers and scattered
thunderstorms found northeast to southwest of the center and only
isolated showers seen to the southwest to northeast of the center.
Convection associated with TS Krosa extends outward about 340 miles
from the center, with additional feeder bands found to the northeast,
south and southwest.

For more information please refer to bulletins from the Joint
Typhoon Warning Center under WMO header WTPN31 PGTW and from the
National Weather Service under WMO header WTPQ31 PGUM.

...OTHER WEATHER SYSTEMS...

MONSOON TROUGH...
The monsoon trough enters the area near 25N137E, extending southeast
to TS Krosa. Another, weaker trough is seen to the southwest of the
main monsoon trough, extending southeast across 130E near 24N, ending
near 10N138E. Scattered showers and isolated thunderstorms are found
between these two troughs. The monsoon trough will continue to drift
north as TS Krosa moves slowly northward.

TRADE-WIND TROUGHS...
There are a few trade-wind troughs moving through the region. The
first is found between Pohnpei and Chuuk, stretching north from near
1N157E to 9N157E. Only spotty clouds and showers are associated with
this trough. The trough looks to continue to move west over the next
couple of days with little change in cloud cover or convection.

The next trough is found farther north, well east of the Marianas,
stretching north-northeast from near 13N158E to 17N160E. Cloudiness
and scattered showers are seen west of the trough. This trough will
continue to move northwest and possibly increase convection leading
into the eastern side of TS Krosa.

The last trade-wind trough is found over the western Marshall
Islands, extending north-northeast from near 3N165E to near 13N170E.
Spotty clouds and showers are found south of 10N with scattered
showers and isolated thunderstorms found north of 10N, where it is
interacting with divergence associated with a weak TUTT over the
area. The trough will continue to move west with little change in
convection.

TUTT...
A weak TUTT enters the area near 25N172E, extending southwest to a
TUTT cell centered near 23N170E. It then turns south to end near
Majuro at 7N172E. Divergence associated with the TUTT is enhancing
convection with the northern end of a trade-wind trough over the
northern Marshall Islands and between Wake Island and Majuro. The
TUTT looks to remain quasi-stationary with little change in strength
over the coming days.

OTHER SYSTEMS...
A high pressure ridge extends west-southwest from well east of the
Marianas near 12N154E to east of Yap near 8N140E. The ridge then
continues northwest to end near 20N135E with a southern branch
extending southeast to end near EQ130E. Convergence south of the
southern branch of the ridge is generating scattered to numerous
showers and isolated thunderstorms well south of Palau and Yap, near
the equator. Otherwise, fair conditions are found with the ridge
across Yap and Chuuk States and the Republic of Palau. This ridge
looks to remain over the region with a slight northerly drift as TS
Krosa continues to slowly move northward.

$$

Kleeschulte