716
AXPQ20 PGUM 100124
TWDPQ
TROPICAL WEATHER DISCUSSION
NATIONAL WEATHER SERVICE TIYAN GU
1124 AM CHST WED SEP 10 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
TRADE-WIND TROUGHS...
THE FIRST TRADE-WIND STRETCHES FROM 3N137E, EXTENDING NORTHWEST
THEN NORTH THROUGH KOROR, CROSSING 20N AT 134E, ENDING NEAR
25N134E, WHICH IS WEST-NORTHWEST OF IWO TO. MOST OF THE CONVECTION
IS FOUND IN TWO AREAS, ALONG THE SOUTHERN PORTION OF THE TROUGH
NEAR KOROR AND POINTS SOUTHWARD WHERE LOW-LEVEL CONVERGENCE IS
STRONGER AND PWATS ARE NEAR OR ABOVE 2.5 INCHES. ANOTHER POCKET IS
ACROSS NORTHERN PORTIONS OF THE THOUGH AXIS NORTH OF 19N. HERE,
MOISTURE IS SLIGHTLY LESS, IN THE 2.25-2.5 INCH RANGE, BUT, A TUTT
CELL IS LOCATED OVERHEAD HELPING TO BOOST ASCENT. BOTH AREA
CONTINUE TO FAVOR SCATTERED SHOWER DEVELOPMENT, WITH ISOLATED
CONVECTION NORTH OF THERE UNTIL YOU GET NEAR THE INFLUENCE OF THE
TUTT CELL, WHERE ISOLATED THUNDERSTORMS ARE DEVELOPING IN ADDITION
TO THE SCATTERED SHOWERS. THIS GENERAL THEME LOOKS TO CONTINUE
THE NEXT FEW DAYS AS THIS LONG TROUGH CONTINUES HEADING WEST.
QUICKLY ON IT'S HEELS IS A TROUGH THAT STRETCHES FROM SOUTHEAST OF
KAYANGEL NEAR 4N138E, WHERE SOME SEMBLANCE OF A WEAK CIRCULATION
IS EVIDENT, THROUGH YAP, ENDING WEST OF THE MARIANAS NEAR 15N142E.
ABUNDANT CLOUD COVER WITH SCATTERED SHOWERS AND AN ISOLATED
THUNDERSTORM OR TWO CONTINUES TO DEVELOP ALONG THIS FEATURE,
WHICH IS FORECAST TO MAINTAIN A SIMILAR CONVECTIVE PATTERN THE
NEXT FEW DAYS AS IT ALSO HEADS WEST.
A WEAK CIRCULATION HAS FORMED NEAR 6N142E, WELL TO THE SOUTHEAST
OF YAP. A SURFACE TROUGH IN THE TRADES EXTENDS NORTHEAST FROM
THIS FEATURE TO 10N148E, TO NEAR 20N152E, WELL TO THE EAST OF THE
CNMI. SCATTERED SHOWERS AND A FEW THUNDERSTORMS ALONG IT FROM THE
CIRCULATION TO 20N ALONG ITS AXIS. THE NUMERICAL FORECASTS SHOW
THIS PATTERN CONTINUING THE NEXT SEVERAL DAYS AS IT HEADS WEST.
FINALLY, A EAST-NORTHEEAST TROUGH EXTENDS, IN A WAVY FORM, FROM
THE CIRCULATION MENTIONED ABOVE TO CHUUK AS IT TURNS EAST PASSING
THROUGH POHNPEI, THEN TURNING NORTHEAST TO UJELANG NORTHEAST OF
POHNPEI NEAR 10M161E, THEN STRADDLING 10 N OR JUST SOUTH OF THERE
TO THE DATE LINE. SCATTERED CLOUDS AND SHOWER ARE PRESENT FROM THE
CIRCULATION EASTWAST-NORTHEAST TO POHNPEI, BECOMING CLOUDY WITH
WIDESPREAD SHOWERS AND SCATTERED THUNDERSTORMS EAST OF THERE TO
THE DATELINE. THE INCREASED COVERAGE IS DUE TO VERY STRONG SURFACE
CONVERGENCE, HIGHER MOISTURE VALUES, AND GOOD DIVERGENCE ALOFT.
THIS TROUGH IS EXPECTED TO LIFT NORTH AND WEST DURING THE
REMAINDER OF THIS WEEK, WEAKENING SOMEWHAT AS IT GETS DISJOINTED
FROM THE ITCZ (INTER-TROPICAL CONVERGENCE ZONE), WITH PERHAPS
ANOTHER CIRCULATION DEVELOPING NORTH OR NORTHEAST OF CHUUK
SOMETIME OVER THE WEEKEND OR EARLY NEXT WEEK. CONVECTIVE COVERAGE
WILL DECREASE BY THEN, BUT STILL REMAIN SCATTERED IN TERMS OF
COVERAGE.
TUTT...
THE TUTT ENTERS THE REGION AT 25N180, CONTINUING WEST TO A CELL
NORTH OF WAKE ISLAND AT 25N168E, WITH THE TUTT AXIS THEN DIPPING
SOUTHWEST TO 20N155E, THEN CONTINUING NORTHWEST TO A CELL NEAR
IWO TO AT 25N141E, THEN SOUTHWEST TO A CELL NEAR 21N135E, ENDING
NEAR 18N130E. CONVECTION, AS IS TYPICALLY THE CASE, IS HIGHEST
NEAR THE CELLS, AND ALONG THE SOUTHERN AXIS OF THE TUTT WHERE
DIVERGENCE HELPS PROVIDE A BOOST TO ASCENT, IN THESE AREAS
SCATTERED TO LOCALLY NUMEROUS SHOWERS CONTINUE TO DEVELOP, WITH
ISOLATED THUNDERSTORMS ALONG THE SOUTHERN AXIS AND SCATTERED
THUNDERSTORMS FOUND NEAR THE TUTT CELLS. THIS ORIENTATION AND
CONVECTIVE PATTERN LOOKS TO REMAIN QUASI-STATIONARY THE NEXT FEW
DAYS.
..ITCZ
THE ITCZ IS LOCATED BETWEEN 3N TO 10N AND FROM 155E TO THE DATE
LINE. MOISTURE LEVELS ARE LOWEST IN THE THE WESTERN OF THE ITCZ
WITH A PWAT RANGE OF 2-2.25 INCHES, WITH WEAK CONVERGENCE NOTED
ALONG IT. FURTHER EAST, CONVERGENCE ALONG THE ITCZ IS MUCH
BETTER, AS IS MOISTURE WITH PWATS OF 2.7-3.2 INCHES, RESULTING IN
WIDESPREAD CONVECTIVE COVERAGE. OVERALL THOUGH, THE CONVERGENCE
ALONG THE ENTIRE LENGTH OF THE ITCZ IS FORECAST TO CONTINUE
GRADUALLY WEAKENING FOR THE REMAINDER OF THE WEEK AND THROUGH THE
WEEKEND, WITH RELEVANT CONVECTION TIED TO THE SURFACE TROUGHS.
DOLL
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