063
AXPQ20 PGUM 050101
TWDPQ

Tropical Weather Discussion
National Weather Service Tiyan GU
1101 AM ChST Sat Oct 5 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 DISTURBANCES...
A tropical disturbance, Invest 99W, is centered east-southeast of
Guam near 12.6N147.4E, about 180 miles ESE of Guam. Latest satellite
imagery shows a consolidating low-level circulation with increasing
convection near the center of 99W. As 99W progresses west-northwest
toward the Marianas, it is moving into a more favorable environment
for development, with Sea Surface Temperatures (SSTs) in the mid 80s
and weak vertical wind shear. 99W is expected to move north-northwest
over the next couple of days toward the Marianas and could move
through the Marianas as a Tropical Depression or weak Tropical Storm
as early as late tonight. For more information on Invest 99W, see
bulletins issued by the Joint Typhoon Warning Center under WMO header
ABPW10 PGTW.

...OTHER WEATHER SYSTEMS...

MONSOON TROUGH...
A weak monsoon trough extends east from the Philippines across 130E
near 13N into a weak circulation northwest of Yap near 12N135E, then
continues eastward to end at Invest 99W. Spotty moderate convection
is seen with the trough west of Invest 99W. As Invest 99W moves
farther north over the next couple of days, it will pull the monsoon
trough along with it. the monsoon trough also looks to strengthen a
bit over the Philippine Sea, resulting in increased convection and
increasing inflow into the Marianas late in the weekend into early
next week.

SURFACE TROUGHS...
An east-west oriented trough is seen extending out of Invest 99W. The
trough extends southeast from 99W, turning east near 9N151E, then
turning back northeast near 9N164E to end north of Kwajalein near
10N168E. Only spotty moderate convection is found with the trough
from north of Kosrae westward to 99W. Strong convergence south of the
trough, however, is producing widespread deep convection just east
of Kosrae to west of Majuro. The trough looks to drift northward
along with Invest 99W over the next couple of days and slowly weaken
north of Pohnpei westward, with the trough splitting near Kosrae and
the eastern portion drifting south and becoming a trade-wind trough
early next week.

UPPER-LEVEL TROUGHS/LOWS...
An upper-level trough extends southwest from a low centered near
25N141E to end near 6N132E. Moderate to deep convection is seen east
of the trough and low. Another weak low is seen near 25N160E with a
trough extending southeast, then splitting into two troughs. The
first trough turns south to end near 19N151E while the second turns
toward the east-northeast to beyond 25N near 173E. Spotty moderate
to deep convection is associated with the troughs and low. These
troughs look to remain fairly stationary over the coming days with
slightly increased convection.

$$

Kleeschulte