533
AXPQ20 PGUM 030120
TWDPQ
TROPICAL WEATHER DISCUSSION
NATIONAL WEATHER SERVICE TIYAN GU
1120 AM CHST TUE JUN 3 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
NEAR EQUATORIAL TROUGH...
THE NEAR-EQUATORIAL TROUGH (NET) EXTENDS JUST INTO GUAM'S AREA OF
RESPONSIBILITY (AOR) AT AROUND 4N130E, STRETCHING SOUTHEAST FROM
EASTERN MINDANAO. THE NET THEN EXTENDS EASTWARD TO JUST SOUTH OF
SONSOROL AT 4N133E, WHERE IT IS CUT OFF BY A SOUTHWARD EXTENSION OF
THE SUBTROPICAL RIDGE. SCATTERED TO NUMEROUS SHOWERS ARE SEEN HUGGING
THE EDGE OF THE AOR ALONG 130E, WITH LOOSE ORGANIZATION ABOUT THE
NET AXIS. THE NET LOOKS TO CONTINUE TO DEVELOP OVER THE COMING DAYS,
WITH MODEL GUIDANCE FAVORING A TRANSITION INTO A MONSOON TROUGH THIS
WEEK AS IT GRADUALLY LIFTS NORTH TOWARD PALAU. THIS WILL LEAD TO
WEST TO SOUTHWEST FLOW OVER PALAU AND YAP DURING THE LATTER HALF OF
THE WEEK, AND BRINGS THE POSSIBILITY OF PROLONGED UNSETTLED WEATHER.
WFO GUAM WILL MONITOR FOR THE POSSIBILITY OF A MONSOON SURGE LATER IN
THE WEEK, WITH ASSOCIATED HEAVY SHOWERS AND STRONG GUSTS.
TRADE-WIND AND SURFACE TROUGHS...
SEVERAL TRADE-WIND TROUGHS ARE SEEN ACROSS GUAM'S AOR. ONE TROUGH IS
SEEN WELL SOUTH OF SOROL, EAURIPIK, AND IFALIK IN YAP STATE,
EXTENDING SOUTHWEST FROM AROUND 6N146E TO 2N140E, BEFORE CURVING
SOUTH TO CROSS THE EQUATOR AT AROUND EQ140E. MODERATE TO DEEP
CONVECTION EXTENDS ROUGHLY NORTHEAST TO SOUTHWEST ALONG THE TROUGH
AXIS. THIS TROUGH LOOKS TO LIFT NORTH-NORTHWEST OVER THE NEXT FEW
DAYS TOWARD PALAU AND YAP PROPER, POTENTIALLY FORMING A WEAK
CIRCULATION WITHIN THE DEVELOPING MONSOON TROUGH. MODEL GUIDANCE
INDICATES THIS DISTURBANCE WILL STRUGGLE TO ORGANIZE OVER THE NEXT
FEW DAYS, BUT IT WILL HELP TO PROMOTE UNSETTLED WEATHER ACROSS FAR
WESTERN MICRONESIA THROUGH THE REST OF THE WEEK.
ANOTHER TROUGH IS SEEN JUST WEST OF THE MARIANAS, EMBEDDED WITHIN THE
BROADER SUBTROPICAL RIDGE ACROSS THE REGION. THIS TROUGH EXTENDS
SOUTH FROM AROUND 17N145E TO 13N143E, AND MODERATE TO DEEP CONVECTION
EXTENDS ALONG ITS AXIS. A FEW ISOLATED THUNDERSTORMS WERE SEEN OVER
MARIANAS COASTAL WATERS THIS MORNING, LIKELY SUPPORTED BY UPPER-LEVEL
DIVERGENCE ASSOCIATED WITH THE TUTT, DISCUSSED BELOW. FURTHER WEST,
AN AREA OF SHOWERS AND THUNDERSTORMS IS SEEN, ASSOCIATED WITH SUBTLE
TROUGHING AND CONVERGENCE WITHIN THE RIDGE. THESE FEATURES WILL
MAINTAIN SHOWERS OVER AND WEST OF THE MARIANAS THROUGH TONIGHT AS
THEY GRADUALLY BEGIN TO MERGE WITH THE DISTURBANCE LIFTING NORTH
TOWARD YAP AND PALAU.
SEVERAL MORE TROUGHS ARE SEEN FURTHER EAST, ONE EXTENDING SOUTH FROM
17N154E TO NORTH OF CHUUK LAGOON NEAR 9N152E, AND ANOTHER TO THE
NORTH OF KOSRAE, EXTENDING SOUTH FROM 11N164E TO 7N164E. SCATTERED TO
NUMEROUS SHOWERS ARE SEEN WITHIN THESE TROUGHS, WITH ISOLATED
THUNDERSTORMS PRESENT IN THE TROUGH EAST OF THE MARIANAS, SUPPORTED
BY THE TUTT. THE TROUGH EAST OF THE MARIANAS LOOKS TO DISSIPATE OVER
THE NEXT DAY WHILE SHIFTING WEST, WHILE THE TROUGH NORTH OF KOSRAE
LOOKS TO MOVE WEST AND INCREASE SHOWERS NEAR POHNPEI THIS EVENING
THROUGH TONIGHT.
TUTT...
THE TUTT LINGERS OVER THE REGION, EXTENDING SOUTH FROM 25N150E AND
INTO A TUTT CELL CENTERED EAST OF THE MARIANAS AROUND 15N152E, THEN
CURVING EAST-NORTHEAST THROUGH ANOTHER CELL CENTERED SOUTHWEST OF
WAKE ISLAND AROUND 18N164E. THE TUTT CONTINUES ON EAST-SOUTHEAST
WHERE IT EXITS THE REGION NEAR 15N180. THE TUTT IS INTERACTING WITH
SEVERAL SURFACE TROUGHS, DISCUSSED ABOVE, TO PRODUCE MODERATE TO DEEP
CONVECTION WELL NORTH OF PALAU AND YAP, DIRECTLY WEST OF AND OVER
THE MARIANAS, AND WELL TO THE NORTH OF POHNPEI. A NORTHERLY JET
STREAK IS LOCATED ALONG THE WESTERN FLANK OF THE TUTT CELL EAST OF
THE MARIANAS AND IS HELPING TO PROMOTE SHOWERS AND THUNDERSTORMS IN
THE AREA. THE TWO TUTT CELLS LOOK TO GRADUALLY MERGE AND SHIFT
WESTWARD OVER THE COURSE OF THE WEEK, LIFTING NORTH-NORTHWEST OF THE
MARIANAS THIS COMING WEEKEND.
..ITCZ
THE ITCZ EXTENDS WESTWARD INTO THE REGION FROM 4N180, CONTINUING
THROUGH THE SOUTHERN MARSHALL ISLANDS TO END NEAR SOUTH OF EBON
ATOLL. SCATTERED SHOWERS ARE SEEN ALONG THE EXTENT, MAINLY WITHIN A
SHALLOW EMBEDDED TROUGH TO THE SOUTH OF MAJURO, AND FURTHER EAST NEAR
THE DATE LINE. ANOTHER, WEAKER FRAGMENT OF THE ITCZ IS SEEN FURTHER
WEST, EXTENDING WESTWARD FROM THE SOUTH OF CHUUK LAGOON NEAR 6N152E,
TO JUST NORTH OF EAURIPIK AT 7N143E. PATCHY, SCATTERED SHOWERS ARE
SEEN DISORGANIZED ACROSS THE REGION, MAINLY OVER AND SOUTH OF WENO,
CHUUK. MODEL GUIDANCE SUPPORTS AN INCREASE IN SHOWERS NEAR KOSRAE,
POHNPEI, AND CHUUK THIS AFTERNOON THROUGH TONIGHT, AS THESE ITCZ
FRAGMENTS SHIFT WEST. THE ITCZ BECOMES POORLY-DEFINED IN THE SECOND
HALF OF THE WEEK.
DECOU
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