538
FXPQ50 PGUM 031952
AFDGUM
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TIYAN GU
552 AM CHST SAT APR 4 2026
MARIANAS UPDATE
A FAIRLY QUIET PATTERN CONTINUES. RADAR AND SATELLITE IMAGERY DEPICT
AN AREA OF SHALLOW, PATCHY SCATTERED SHOWERS SHIFTING WEST OF SAIPAN
AND TINIAN EARLY THIS MORNING, ASSOCIATED WITH A TRANSIENT WEAK
TROUGH. TO THE EAST, A NARROW LINE OF SHOWERS APPROACHES GUAM AND
ROTA WATERS AS THE REMNANTS OF WEAK OUTFLOW. A MOSTLY DRY REGIME WILL
CONTINUE FOR MUCH OF THE COMING WEEK, AND THERE WAS LITTLE CHANGE TO
THE FORECAST. WIND SPEEDS ARE EXPECTED TO SEE AN INCREASE THROUGH
TONIGHT AS HIGH PRESSURE PUSHES FURTHER EAST OFF THE COAST OF JAPAN,
INCREASING THE REGIONAL PRESSURE GRADIENT AND PRODUCING A TRADE-WIND
SURGE THROUGH EARLY NEXT WEEK. MODERATE TO FRESH WINDS ARE EXPECTED,
INCREASING NEAR 22 KNOTS AT TIMES SUNDAY AND MONDAY, AND CONTRIBUTING
TO INCREASINGLY CHOPPY SEAS. SEAS LOOK TO BECOME HAZARDOUS TO SMALL
CRAFT MONDAY AND TUESDAY AS COMBINED SEA HEIGHTS REACH 9 TO 11 FEET,
DUE TO INCREASING TRADE SWELL, WIND WAVES, AND THE ARRIVAL OF WEAK
NORTHERLY SWELL ON MONDAY. THE INCREASE IN SWELL WILL ALSO BUILD SURF
ALONG NORTH AND EAST-FACING REEFS, LIKELY INCREASING THE RISK OF RIP
CURRENTS FROM MODERATE TO HIGH FOR EAST-FACING REEFS SUNDAY OR SUNDAY
NIGHT, AND BRINGING ELEVATED SURF FOR NORTH-FACING REEFS.
EASTERN MICRONESIA UPDATE
THERE WAS LITTLE TO CHANGE IN THE FORECAST. THE MAIN FEATURE OF
INTEREST REMAINS A DISORGANIZED TROPICAL DISTURBANCE CENTERED NEAR
THE SOUTHERN MARSHALL ISLANDS, ALONG THE FAR EASTERN EXTENT OF THE
NEAR-EQUATORIAL TROUGH (NET). THERE IS A BROAD AREA OF STRONG
CONVERGENCE ACROSS THE RMI, FOCUSED ALONG THE EASTERN PERIPHERY OF
THE DISTURBANCE WHERE IT IS INTERACTING WITH A TRADE-WIND TROUGH, AND
NUMEROUS TO WIDESPREAD SHOWERS CAN BE SEEN ACROSS THE AREA. THE BULK
OF SHOWERS ARE STILL FOCUSED EAST OF MAJURO, WHICH REMAINED
RELATIVELY DRY OVERNIGHT. LATEST GUIDANCE SUPPORTS NUMEROUS LOCALLY
HEAVY SHOWERS AND ISOLATED THUNDERSTORMS FOR MAJURO THROUGH TODAY AS
THE DISTURBANCE AND TROUGH GRADUALLY SHIFT WESTWARD, WITH PATCHIER
COVERAGE THERE OVERNIGHT AS THE BEST CONVERGENCE SHIFTS OVER THE
WESTERN MARSHALLS. AT THE SAME TIME, POHNPEI AND KOSRAE CAN EXPECT
INCREASING SHOWER AND THUNDERSTORM CHANCES TONIGHT AS THE NET FLEXES
SLIGHTLY NORTHWARD, AND CONVERGENCE INCREASES DUE TO THE BUILDING
TRADE-WIND SURGE TO THE NORTH. INCREASING TRADE WINDS AND SWELL WILL
CONTRIBUTE TO INCREASINGLY CHOPPY SEAS FOR POHNPEI THROUGH THE REST
OF THE WEEKEND, AND CONDITIONS MAY BRIEFLY BECOME HAZARDOUS TO SMALL
CRAFT AROUND LATE SUNDAY NIGHT AS COMBINED SEAS INCREASE TO NEAR 10
FEET. THIS WILL ALSO LEAD TO ELEVATED, POTENTIALLY HAZARDOUS SURF
ALONG NORTH FACING REEFS.
WESTERN MICRONESIA UPDATE
A QUIETER PATTERN CONTINUES ACROSS WESTERN MICRONESIA, AND THERE WAS
LITTLE CHANGE TO THE FORECAST. PALAU, YAP, AND CHUUK WILL REMAIN IN
A DRIER TRADE-WIND REGIME TODAY. LATE TONIGHT, CHUUK WILL SEE AN
INCREASE IN SHOWERS AS CONVERGENCE BUILDS NORTH OF THE NET AXIS,
ASSOCIATED IN LARGE PART WITH THE DEVELOPING TRADE-WIND SURGE TO THE
NORTH. STRONGER TRADE WINDS AND ASSOCIATED SWELL WILL CONTRIBUTE TO
INCREASINGLY CHOPPY SEAS FOR CHUUK THROUGH THE REST OF THE WEEKEND,
AND CONDITIONS MAY BECOME HAZARDOUS TO SMALL CRAFT BY MONDAY MORNING
AS COMBINED SEAS INCREASE TO 9 TO 11 FEET. THIS WILL ALSO LEAD TO
ELEVATED, LIKELY HAZARDOUS SURF ALONG NORTH FACING REEFS. SEAS ARE
EXPECTED TO REMAIN BENIGN FOR PALAU AND YAP COASTAL WATERS FOR THE
COMING WEEK.
PREV DISCUSSION
/ISSUED 504 PM CHST FRI APR 3 2026/
MARIANAS SYNOPSIS...
A FAIRLY DRY TRADE-WIND PATTERN EXTENDS ACROSS THE AREA WITH RADAR
SHOWING ISOLATED TRADE SHOWERS MOVING THROUGH THE FLOW. WINDS ARE
GENTLE TO MODERATE AND SEAS ARE AROUND 4 TO 6 FEET ACCORDING TO BUOY
AND ALTIMETRY DATA. EXPECTING SEAS AND WINDS TO BUILD THIS WEEKEND
AS A TRADE-WIND SURGE DEVELOPS EAST OF THE MARIANAS.
DISCUSSION...
THIS SEASONAL TRADE-WIND PATTERN IS EXPECTED THROUGH THE MIDDLE OF
NEXT WEEK AS SATELLITE IMAGERY ONLY SHOWS A COUPLE OF WEAK TRADE-
WIND TROUGHS MOVING THROUGH THE FLOW TO THE EAST OF THE MARIANAS. THE
LEADING EDGE OF A DEVELOPING TRADE-WIND SURGE NEAR THE MARSHALL
ISLANDS IS EXPECTED TO INCREASE WINDS TO MODERATE TO FRESH STARTING
SATURDAY, WITH BREEZY CONDITIONS DURING THE DAYTIME HOURS OF SUNDAY
AND MONDAY. WINDS ARE THEN EXPECTED TO SUBSIDE SLIGHTLY TUESDAY AND
WEDNESDAY AS THE TRADE-WIND SURGE WEAKENS AND SHIFTS BACK TOWARDS
THE EAST. LONG-RANGE GUIDANCE WEAK TROPICAL DISTURBANCE IN EASTERN
MICRONESIA WILL SLOWLY SHIFT WESTWARD INTO CENTRAL MICRONESIA BEFORE
POTENTIALLY LIFTING NORTHWARD AND CLOSER TO THE MARIANAS NEXT
WEEKEND. THIS WOULD INCREASE THE POTENTIAL FOR SHOWERS,
THUNDERSTORMS, AND SOME GUSTY WINDS AROUND THE MARIANAS, BUT THIS IS
STILL AT LEAST 7 TO 10 DAYS OUT SO UNCERTAINTY IN THE FORECAST
REMAINS FAIRLY HIGH AT THIS TIME.
MARINE...
GENTLE TO MODERATE NORTHEAST WINDS AND COMBINED SEAS OF 4 TO 6
FEET PREVAIL ACROSS THE REGION TONIGHT. A TRADE-WIND SURGE WILL THEN
DEVELOP OVER THE WEEKEND, RESULTING IN WINDS INCREASING TO MODERATE
TO FRESH ACROSS THE MARIANAS, AND GETTING CLOSE TO 22 KT SUNDAY AND
MONDAY. AN INCREASE IN TRADE-WIND SWELL AND WIND WAVES WILL ALSO
BUILD SEAS TO 6 TO 9 FEET OVER THE WEEKEND. THEN, NORTHERLY SWELL
LOOKS TO ARRIVE MONDAY, WHEN SEAS ARE ANTICIPATED TO REACH 9 TO 11
FEET, BECOMING HAZARDOUS FOR SMALL CRAFT. WINDS AND SEAS ARE THEN
EXPECTED TO SUBSIDE SLIGHTLY AROUND MIDWEEK. A MODERATE RISK OF RIP
CURRENTS ALONG NORTH AND EAST FACING REEFS AND LOW RISK ALONG SOUTH
AND WEST FACING REEFS CONTINUES OVER THE NEXT COUPLE DAYS, WITH THE
PRIMARY SWELL FROM THE NORTHEAST. AN INCREASE IN EAST-NORTHEAST TRADE
WINDS AND SWELL OVER THE WEEKEND AND THE ARRIVAL OF NORTHERLY SWELL
ON MONDAY ARE EXPECTED TO BUILD SURF ALONG EAST AND NORTH FACING
REEFS, LIKELY INCREASING THE RIP RISK TO HIGH FOR EAST-FACING REEFS
STARTING SUNDAY AND POTENTIALLY PRODUCING HAZARDOUS SURF OF 9 FEET
FOR NORTH-FACING REEFS.
EASTERN MICRONESIA...
SATELLITE IMAGERY SHOWS PARTLY TO MOSTLY CLOUDY SKIES AND ISOLATED
TO SCATTERED SHOWERS ACROSS EASTERN MICRONESIA. ALTIMETRY DATA SHOWS
COMBINED SEAS BETWEEN 5 AND 8 FEET ACROSS THE REGION.
OVERALL, LITTLE HAS CHANGED WITH THE OBSERVED WEATHER ACROSS EASTERN
MICRONESIA. SHOWER COVERAGE HAS BEEN LOWER THAN EXPECTED ACROSS
MAJURO WITH SCATTERED SHOWERS SEEN, WHILE ISOLATED SHOWERS ARE
OCCURRING NEAR POHNPEI AND KOSRAE. THE MAIN FORECAST TREND WAS TO
DIAL DOWN POPS A BIT AND DELAY WIDESPREAD RAINFALL CONDITIONS. THIS
FORECAST HAD A HEAVY LEAN TOWARDS THE ECMWF, WHICH BETTER REFLECTED
THE CURRENT OBSERVATIONS THAN THE GFS. DESPITE THE DOWNTREND,
NUMEROUS SHOWERS ARE EXPECTED THIS WEEKEND AND INTO NEXT WEEK FOR
MAJURO AND THEN KOSRAE AND POHNPEI. AS THE TROPICAL DISTURBANCE
ORGANIZES, WIDESPREAD SHOWERS ARE EXPECTED AT POHNPEI AND KOSRAE
TOWARDS THE END OF THE PERIOD.
OVERALL, THERE IS LITTLE CHANGE IN THOUGHT FOR MARINE CONDITIONS.
COMBINED SEAS ARE BETWEEN 5 AND 8 FEET ACROSS THE REGION. A TRADE-
WIND SWELL WILL ALLOW SEAS TO RISE ANOTHER FOOT. FOR KOSRAE AND
MAJURO, SEAS LOOK TO REMAIN BENIGN OUTSIDE OF SHOWERS AND
THUNDERSTORMS, BUT COULD BECOME CHOPPY DURING SHOWERS. FOR POHNPEI,
THE TRADE-WIND SWELL LOOKS JUST MISS TO THE NORTH, BUT SEAS LOOK TO
RISE ENOUGH TO CAUSE HAZARDOUS SURF FOR NORTH FACING REEFS.
WESTERN MICRONESIA...
AFTERNOON SATELLITE IMAGERY SHOWS THE NEAR-EQUATORIAL TROUGH (NET)
REMAINS TO THE SOUTH OF THE THREE FORECAST POINTS WITH ISOLATED TO
SCATTERED SHOWERS NOTED ALONG THE NET AXIS. SCATTERED SHOWERS ARE
EXPECTED AT BOTH PALAU AND CHUUK TONIGHT WHILE SHOWERS REMAIN
ISOLATED AT YAP. SHOWER CHANCES SHOULD REMAIN ISOLATED AT ALL THREE
SITES ON SATURDAY. A WET PATTERN IS EXPECTED AT CHUUK STARTING
SATURDAY NIGHT WITH SHOWER CHANCES INCREASING TO NUMEROUS BY SUNDAY
NIGHT. ISOLATED THUNDERSTORMS AND LOCALLY HEAVY RAINFALL WILL BE
POSSIBLE AT CHUUK STARTING LATE ON SUNDAY AS A TRADE-WIND SURGE NEAR
THE MARSHALL ISLANDS MOVES WESTWARD. GENTLE TO MODERATE NORTHEAST
WINDS ARE EXPECTED TO PREVAIL AT PALAU AND YAP THROUGH THE WEEKEND,
THOUGH YAP MAY EXPERIENCE PERIODS OF LOW-END FRESH WINDS STARTING ON
SUNDAY. GENTLE TO MODERATE NORTHEAST WINDS AT CHUUK WILL QUICKLY
BECOME MODERATE TO FRESH STARTING ON SATURDAY WITH A POTENTIAL FOR
STRONG WINDS STARTING ON SUNDAY AS THE TRADE-WIND SURGE IS EXPECTED
TO IMPACT CENTRAL MICRONESIA. ATTENTION THEN TURNS TO MID TO LATE
NEXT WEEK AS A TROPICAL DISTURBANCE IS FORECAST TO IMPACT CENTRAL
MICRONESIA.
ALTIMETRY PASSES FROM THIS MORNING SHOW SEAS AROUND 4 FEET JUST WEST
OF PALAU AND SEAS 4 TO 6 FEET IN THE VICINITY OF CHUUK. COMBINED
SEAS WILL REMAIN AROUND 3 TO 5 FEET AT PALAU THROUGH THE WEEKEND,
BUILDING BY A FOOT OR SO AS WE HEAD INTO NEXT WEEK. SEAS WILL
INCREASE AT YAP TO AROUND 6 TO 7 FEET BY MONDAY. CHUUK'S SEAS WILL
INCREASING SIGNIFICANTLY, LIKELY TO HAZARDOUS TO SMALL CRAFT OF 10
FEET, STARTING ON SUNDAY AS A TRADE-WIND SURGE AND A NORTHEAST SWELL
MOVE IN. HAVE ADDED A HEADLINE FOR BUILDING SEAS AND HIGH SURF ALONG
NORTH FACING REEFS FOR CHUUK STARTING ON SUNDAY. A SMALL CRAFT
ADVISORY STARTING ON SUNDAY IS LIKELY FOR THE COASTAL WATERS OF
CHUUK, WITH THE POTENTIAL FOR A HIGH SURF ADVISORY ALONG AT THE LEAST
NORTH FACING REEFS ALSO POSSIBLE LATE THIS WEEKEND AND INTO EARLY
NEXT WEEK.
GUM WATCHES/WARNINGS/ADVISORIES
GU...NONE.
MP...NONE.
MARIANAS WATERS...NONE.
MARIANAS/EAST AND WEST MICRONESIA UPDATE: DECOU
MARIANAS: SCHANK
EAST MICRONESIA: WILLIAMS
WEST MICRONESIA: WHISNANT
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