786
AXPQ20 PGUM 130102
TWDPQ

Tropical Weather Discussion
National Weather Service Tiyan GU
1102 AM ChST Sat Jul 13 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...

MONSOON TROUGH...
A monsoon trough continues to generate unsettled weather in western
Micronesia, stretching across 2n130e, bending southeastward through
Palau, south of eastern Yap State and ending at a trade-wind
disturbance south of Chuuk, near 20n152e. A surge in moist, west-
southwesterlies is evident on the southern side of this trough, where
robust, deep convection is occurring, largely affecting southern
Palau. Trade convergence on the northern peripheries is also
generating showers and a few thunderstorms, extending over Yap State.
This pattern is expected to linger in far western Micronesia through
early next week, with convection shifting north at times, following
passing disturbances moving within the boundary.

TRADE-WIND TROUGHS...
Multiple trade-wind troughs are found across the AOR. One trough is
traversing the Marianas, from knee to 23n150e, where it is linking
up with a TUTT cell. A series of minor troughs between the Marianas
and the Phillipines are also gaining support from the TUTT, where
spotty showers and a few thunderstorms are found in an area between
14N and 18N, from 130E to 142E. To the east of the Marianas, another
series of minor troughs are also found within a moderate trade surge,
from 147E to 160E. Scattered showers are found along these features,
isolated thunderstorms are found closer to the TUTT, near the CNMI.
In eastern Micronesia, several troughs are embedded within the ITCZ,
a couple of notable troughs are found from 3n158e to knee and the
other extends from knee to knee. Scattered to numerous showers and
isolated thunderstorms are found along these features. The northern
extent of these troughs are also enhanced be the trade-wind surge in
the area. These features will continue propagating westward,
following the synoptic pattern.

TRADE-WIND SURGE...
A trade wind-surge is evident on scatterometry data, between 8N and
25N, from 150E to beyond the Date Line. Pockets of moderate to fresh
winds aid low-level convergence, leading to patchy showers in this
area, including the northern Marshalls and in open waters north of
Chuuk and Pohnpei. This surge may stretch into eastern Micronesia
over the next few days until the surface high to the distant north
continues to propagate eastward, relaxing the pressure gradient in
the region in the second half of next week.

TUTT...
The Tropical Upper Tropospheric Trough (TUTT) is draped across the
northern half of the AOR, passing through two weak upper-level lows
located at 25N162E and 16N146E, then bows northwestward towards the
Phillipines. Spotty thunderstorms are found around the TUTT cells
and enhancing areas of convection are found along the southside of
the TUTT, this includes the CNMI. These features are expected to
propagate westward and models show another TUTT cell setting up north
of the Marianas towards the middle of next week.

...ITCZ...
An Inter-Tropical Convergence Zone (ITCZ) pattern stretches across
eastern Micronesia, passing the Date Line around 5N and meandering
through the region, passing near Majuro, Kosrae and Pohnpei, then
meets a weak circulation south of Chuuk, around 5N150E. Pockets of
moderate to strong convection are found along this boundary,
especially with embedded troughs that are helping extend showers
farther north. Over the next several days, the ITCZ is expected to
stretch farther west, lifting north and fragmenting at times.

$$

IC