283
AXPQ20 PGUM 130143
TWDPQ
TROPICAL WEATHER DISCUSSION
NATIONAL WEATHER SERVICE TIYAN GU
1143 AM CHST MON APR 13 2026
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...
SUPER TYPHOON SINLAKU (04W) IS CURRENTLY CENTERED NEAR 12.2N
148.9E, OR ABOUT 290 MILES EAST-SOUTHEAST OF GUAM. MAXIMUM
SUSTAINED WINDS HAVE INCREASED TO 180 MPH, AND SINLAKU CONTINUES
TO MOVE NORTHWEST TOWARD THE MARIANAS, 305 DEGREES AT 9 MPH.
HIMAWARI VISIBLE SATELLITE SHOWS HEAVY RAIN SPREAD ACROSS A WIDE
AREA EXTENDING ROUGHLY 300 MILES OUTWARD FROM THE CENTER, WITH GLD
NETWORK DATA SHOWING FREQUENT TO CONSTANT LIGHTNING WITHIN THE
10-15 MILE WIDE EYEWALL. THE LATEST STORM TRACK FROM THE JOINT
TYPHOON WARNING CENTER (JTWC) HAS SHOWN A SLIGHT SOUTHWARD SHIFT
IN THE STORM PATH DURING ITS PASSAGE TOWARD THE MARIANAS, STILL
MAINTAINING A TRACK NORTH OF ROTA, PASSING NEAR OR OVER TINIAN AND
SAIPAN AROUND TUESDAY AFTERNOON THROUGH TUESDAY NIGHT. SINLAKU IS
EXPECTED TO GRADUALLY WEAKEN THROUGH THE NEXT FEW DAYS, BUT IS
STILL EXPECTED TO CROSS THE MARIANAS AS A CATEGORY 4 OR 5 TYPHOON.
CURRENT PGUA RADAR IMAGERY AS OF THIS MORNING SHOWS THE OUTER
HEAVY SHOWER BANDS OF STY SINLAKU ROTATING THROUGH MARIANAS
COASTAL WATERS JUST EAST OF THE ISLANDS. THESE SHOWERS ARE
EXPECTED TO INCREASE AND MOVE DIRECTLY OVER THE MARIANAS THROUGH
THE AFTERNOON AND EVENING, WITH RAPIDLY WORSENING CONDITIONS
EXPECTED LATE TONIGHT THROUGH TUESDAY AS SINLAKU MOVES IN.
FOR MORE INFORMATION PLEASE REFER TO BULLETINS FROM THE JOINT
TYPHOON WARNING CENTER UNDER WMO HEADER WTPN31 PGTW AND FROM THE
NATIONAL WEATHER SERVICE UNDER WMO HEADER WTPQ31 PGUM.
..OTHER WEATHER SYSTEMS
NEAR-EQUATORIAL TROUGH...
A NEAR-EQUATORIAL TROUGH (NET) STILL EXTENDS EAST-NORTHEAST INTO
THE REGION FROM 6N130E AND INTO STY SINLAKU, PASSING OVER PALAU
AND SOUTH OF YAP. PATCHY ISOLATED TO SCATTERED SHOWERS ARE SEEN
ALONG AND SOUTH OF THE TROUGH AXIS. THE NET WILL SHIFT SLIGHTLY
NORTHWARD OVER THE NEXT DAY OR SO, BECOMING INDISTINCT AS THE
BROADER WIND FIELD ACROSS WESTERN MICRONESIA AND THE PHILIPPINE
SEA IS INCREASINGLY DOMINATED BY STY SINLAKU AS IT MOVES
NORTHWEST.
TRADE-WIND TROUGHS...
A ROBUST TRADE-WIND TROUGH IS SEEN WITHIN THE TRAILING CONVERGENCE
WELL EAST OF STY SINLAKU AND NORTH OF KOSRAE, EXTENDING NORTH-
NORTHEAST FROM 8N163E TO 14N166E. NUMEROUS SHOWERS AND SCATTERED
THUNDERSTORMS ARE SEEN WITHIN THE TROUGH. THIS FEATURE IS EXPECTED
TO WEAKEN, REMAINING FAIRLY STATIONARY THROUGH THE NEXT FEW DAYS
AS SINLAKU PULLS AWAY TO THE NORTHWEST, MAINTAINING SHOWERS AND
THUNDERSTORMS OVER THE NORTHERN RMI, NORTHWEST OF MAJURO ATOLL.
TRADE-WIND SURGE...
A LARGE TRADE-WIND SURGE CONTINUES NORTH OF SUPER TYPHOON SINLAKU
TO AROUND 21N, FROM AROUND 135E TO 170E, WITHIN THE STRONG
PRESSURE GRADIENT BETWEEN SINLAKU AND HIGH PRESSURE WELL TO THE
NORTH AND NORTHEAST. ASIDE FROM THE OUTER RAIN BANDS OF STY
SINLAKU AND THE TRAILING CONVERGENCE TO ITS EAST, PATCHY SCATTERED
SHOWERS AND CLOUD COVER ARE SEEN WITHIN THE TRADE-WIND SURGE TO
THE NORTH OF THESE FEATURES. THE EASTERLY TRADE WINDS WILL WEAKEN
EAST TOWARD THE DATE LINE OVER THE NEXT FEW DAYS AS STY SHIFTS
NORTHWESTWARD, AND HIGH PRESSURE TO THE NORTHEAST MOVES FURTHER
AWAY.
OTHER SYSTEMS...
A WESTERLY WIND BURST (WWB) IS LOCATED SOUTH OF STY SINLAKU TO
SOUTH OF THE EQUATOR, WITH OVERNIGHT SCATTEROMETRY SHOWING FRESH
TO STRONG WEST-NORTHWEST TO WEST WINDS, ABOUT 20 TO 30 KT FROM
135E TO 155E. AS STY SINLAKU GRADUALLY SHIFTS NORTHWEST ACROSS
THE MARIANAS, THIS AREA OF WESTERLIES WILL SHIFT WEST, CREATING
SEAS HAZARDOUS TO SMALL CRAFT ACROSS MUCH OF YAP STATE, INCLUDING
YAP PROPER, INTO MIDWEEK, AND POTENTIALLY AN INCREASE IN CHOPPIER
SEAS NEAR THE REPUBLIC OF PALAU AROUND MIDWEEK.
..ITCZ
AN INTERTROPICAL CONVERGENCE ZONE (ITCZ) EXTENDS WESTWARD FROM
ACROSS THE DATE LINE NEAR 12N AND OVER THE NORTHERN MARSHALL
ISLANDS, THEN PASSING NORTH OF POHNPEI AND KOSRAE WHERE IT MEETS
THE NORTHERN PERIPHERY OF STY SINLAKU. SCATTERED TO NUMEROUS
SHOWERS AND ISOLATED THUNDERSTORMS EXTEND ACROSS THE CONVERGENCE
BOUNDARY BETWEEN THE EASTERLY TRADE WINDS, AND THE EAST-SOUTHEAST
TO SOUTHEAST WINDS FLOWING INTO STY SINLAKU. THE HEAVIEST SHOWERS
AND STRONGEST CONVERGENCE ARE SEEN JUST NORTHWEST OF KWAJALEIN
ATOLL. THE ITCZ WILL SHIFT NORTH AND FRAGMENT THROUGH THE MIDDLE
OF THE WEEK AS SINLAKU MOVES NORTHWEST ACROSS THE MARIANAS.
DECOU
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