531
AXPQ20 PGUM 262338
TWDPQ

Tropical Weather Discussion
National Weather Service Tiyan GU
938 AM ChST Sat Jul 27 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 CYCLONES...
A circulation labeled Invest 95W by JTWC, is west-southwest of
Koror at about 7.5N132E. It is currently rated as a "Medium"
potential for TC formation within 24 hours. Large areas of showers
and isolated thunderstorms with locally gusty winds are seen from
just northwest of Yap and northwest of Koror to beyond 130E.
Patchy showers are also near Yap and Koror and over parts of
southeast Yap State. Invest 95W will move slowly toward northwest
and gradually develop as it moves through the Philippine Sea.

MONSOON TROUGH AND TROPICAL DISTURBANCES...
The monsoon trough extends eastward from 95W at 7.5N132E to just
northwest of Weno Chuuk at 9N150E, then curves southeastward
thru a weak circulation southwest of Pohnpei at 4N155E, ending at
EQ160E. Areas of showers and thunderstorms have been developing
in the cyclonically curved flow around the circulation at 4N155E.
Heavy showers are seen just northeast of Weno centered at 9N153E,
and from just south of Weno to just south of Pohnpei between 6N
and 2N from 150E to 160E.

The monsoon trough is in a transition phase while the circulation
southwest of Pohnpei will need to be monitored. The circulation
will likely continue to cause showers and thunderstorms, along
with locally gusty winds, and can be expected to move toward the
northwest in the coming days.

...OTHER WEATHER SYSTEMS...

TRADE-WIND TROUGHS...
A surface trough moving westward over Kosrae State is causing
scattered showers and a few thunderstorms within 75 miles of a
line from 2N164E to 7N164E.

A second westward-moving trough approaching the Date Line is
producing heavy showers from 5N to 13N east of 178E to beyond 180.

A third westward-moving trough approaching the Mariana Islands is
causing patchy showers within 75 miles of a line from 12N148E to
19N148E.

CONVERGING SURFACE WINDS...
Converging southeast to east surface winds, aiding by a strongly
divergent flow aloft, are producing showers and thunderstorms in a
large area northwest of the Mariana islands. The area is within
125 miles of a line from near Saipan at 16N145E to southwest of
Iwo To at 21N137E.

TUTT...
The TUTT system is complex today. A TUTT Cell, or upper-level
low, is centered southwest of Iwo To at 20N140E, with an upper
level trough running north to south through the Cell. Divergent
winds around the Cell are helping the development of deep
convection in the area of convergent surface winds northwest of
the Marianas, as mentioned above.

From the TUTT Cell at 20N140E, a TUTT runs eastward thru another
TUTT Cell northwest of Wake Island at 23N159E eastward to beyond
25N180. The Cell at 23N159E is causing showers and thunderstorms
northwest of Wake within 100 miles of 21N162E.

The TUTT southwest of Iwo To has become a little stronger and the
TUTT extending eastward from 20N140E is slightly farther north of
Wake Island. The TUTT Cells will continue to trigger areas of deep
convective thunderstorms as they remain over the region embedded
in the TUTT, or upper-level trough, stretched across northern
parts of Micronesia.

...ITCZ...
The ITCZ is weakly stretched across Eastern Micronesia today,
mainly between 3N and 5N from 160E to beyond the Date Line. Most
of the shower activity in the region is associated with the
surface troughs mentioned above.

$$

Simpson