765
FXPQ50 PGUM 242012
AFDGUM
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TIYAN GU
612 AM CHST SAT APR 25 2026
MARIANAS UPDATE
MOSTLY CLEAR TO PARTLY CLOUDY SKIES ARE PRESENT ACROSS THE MARIANAS.
LITTLE TO NO CHANGES WERE MADE WITH THIS FORECAST PACKAGE. DRY
CONDITIONS LOOK TO CONTINUE TODAY THROUGH SUNDAY BEFORE A SURFACE
TROUGH APPROACHES THE MARIANAS SUNDAY NIGHT. SCATTERED SHOWERS REMAIN
POSSIBLE SUNDAY NIGHT THROUGH TUESDAY.
BENIGN SEAS OF 4 TO 6 FEET WILL PERSIST INTO TONIGHT, AND THEN WILL
RISE SLIGHT TO 6 TO 8 FEET BY THE END OF THE FORECAST PERIOD. A HIGH
RISK FOR RIP CURRENTS WILL BE POSSIBLE LATE THIS WEEKEND ALONG EAST
FACING REEFS WITH HAZARDOUS SURF POSSIBLE ALONG NORTH FACING REEFS.
EASTERN MICRONESIA UPDATE
SATELLITE OBSERVATIONS SHOW NUMEROUS SHOWERS AND ISOLATED
THUNDERSTORMS ACROSS POHNPEI AND KOSRAE, WITH SCATTERED SHOWERS SEEN
ELSEWHERE. NO ADJUSTMENTS WERE MADE TO THE FORECAST. HOWEVER,
INCREASING POHNPEI'S POPS TO WIDESPREAD 80% WAS CONSIDERED. THE MAIN
REASON TO MAINTAIN NUMEROUS SHOWERS WAS SATELLITE THIS MORNING
SHOWING SHOWERS AND THUNDERSTORMS WERE STRUGGLING TO MOVE INTO
POHNPEI EARLY THIS MORNING. CONVECTION HAS START TO MOVE INTO POHNPEI
RECENTLY, BUT CLOUD TOPS HAVE WARMED.
BENIGN COMBINED SEAS OF 5 TO 7 FEET WILL PERSIST THROUGH THE PERIOD,
EXCEPT WITHIN HEAVY SHOWERS AND THUNDERSTORMS. SURF WILL BE ELEVATED
ALONG NORTH FACING REEFS OF POHNPEI AND KOSRAE THIS WEEKEND, BUT LOOK
TO REMAIN BELOW HAZARDOUS CRITERIA.
WESTERN MICRONESIA UPDATE
SATELLITE SHOWS IMPROVING CONDITIONS ACROSS PALAU AND YAP AND SHOWERS
AND THUNDERSTORMS MOVE AWAY. OVER THE LAST HOUR OR TWO, A
THUNDERSTORM COMPLEX HAS DEVELOPED OVER THE NORTHERN COASTAL WATERS
OF WENO. THIS CONVECTION LOOKS TO EXPAND AND OVERTAKE WENO OVER THE
NEXT HOUR OR TWO. SHOWERS AND THUNDERSTORMS LOOK TO DECREASE IN
COVERAGE OVER CHUUK SLIGHTLY THIS AFTERNOON, BEFORE INCREASE FROM
SCATTERED TO NUMEROUS SHOWERS TONIGHT. A BRIEF LULL IN SHOWERS AND
THUNDERSTORMS IS EXPECTED FOR YAP AND PALAU ON SUNDAY AND MONDAY
BEFORE ANOTHER ROUND OF ACTIVE WEATHER LOOKS TO MOVE IN TUESDAY AND
WEDNESDAY.
COMBINED SEAS ARE GENERALLY BETWEEN 5 AND 8 FEET. SEAS WILL REMAIN
BENIGN IN CALM CONDITIONS, BUT WILL BECOME CHOPPY DURING PERIODS OF
HEAVY SHOWERS, ESPECIALLY ACROSS CHUUK.
PREV DISCUSSION
/ISSUED 918 PM CHST FRI APR 24 2026/
MARIANAS SYNOPSIS...
GENTLE TO MODERATE TRADE WINDS PERSIST ACROSS THE MARIANAS, WITH
LARGELY CLEAR AND DRY CONDITIONS AS SEEN ON SATELLITE AND DOPPLER
RADAR. BRIEF, LIGHT SHOWERS REMAIN POSSIBLE SATURDAY MORNING FOR
TINIAN AND SAIPAN. A WETTER PATTERN IS EXPECTED TO BEGIN AS SOON AS
SUNDAY NIGHT.
DISCUSSION...
A DRY TRADE-WIND PATTERN CONTINUES ACROSS THE MARIANAS THROUGH SUNDAY
AS PRECIPITABLE WATER VALUES RANGE FROM 1 TO 1.25 INCHES, LIMITING
THE POTENTIAL FOR SHOWERS. THE EXCEPTION IS A SLIGHT CHANCE OF
SHOWERS FOR TINIAN AND SAIPAN SATURDAY MORNING AS A WEAK TROUGH
PASSES JUST NORTH OF THE ISLANDS. SHOWERS ARE EXPECTED TO INCREASE
SOMETIME SUNDAY NIGHT OR MONDAY MORNING AS A BROAD TRADE-WIND TROUGH
BRINGS SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS FOR THE WHOLE
MARIANAS. WINDS WILL INCREASE FROM MODERATE TO FRESH WITH THE
ARRIVAL OF THE TROUGH. THESE WINDS MAY PERSIST FOR THE REST OF THE
FORECAST PERIOD AS THE PRESSURE GRADIENT DEEPENS BETWEEN THE TROPICS
AND MID-LATITUDES.
MARINE...
COMBINED SEAS OF 4 TO 6 FEET WILL INCREASE ONCE AGAIN EARLY NEXT
WEEK AS TRADE SWELL AND WIND WAVES STRENGTHEN. A MODERATE RISK OF
RIP CURRENTS IS EXPECTED ALONG NORTH AND EAST FACING REEFS OF THE
MARIANAS FOR AT LEAST THE NEXT SEVERAL DAYS. THE AFOREMENTIONED
STRENGTHENING TRADE SWELL AND HIGHER WIND WAVES MAY PRODUCE A HIGH
RISK OF RIP CURRENTS ALONG EAST FACING REEFS BY THE MIDDLE OF NEXT
WEEK, WITH SOME CHANCE OF HAZARDOUS SURF DEVELOPING ALONG NORTH
FACING REEFS.
EASTERN MICRONESIA...
AN INTERTROPICAL CONVERGENCE ZONE (ITCZ) FRAGMENT IS PRODUCING
SCATTERED TO NUMEROUS SHOWERS AND ISOLATED THUNDERSTORMS ACROSS THE
SOUTHERN MARSHALL ISLANDS AND SOUTHERN KOSRAE STATE. POCKETS OF
SCATTERED SHOWERS ARE ALSO FOCUSED AROUND VARIOUS TRADE-WIND TROUGHS
NORTH OF THIS BOUNDARY, ACROSS THE MAIN ISLANDS OF POHNPEI AND KOSRAE
AND NORTHEAST OF MAJURO. A FRAGMENTED ITCZ PATTERN, POSSIBLE WEAK,
EMBEDDED DISTURBANCES, AND CONVERGENT, MODERATE TO FRESH EAST-
NORTHEAST TRADES ARE EXPECTED TO SUPPORT AN UNSETTLED WEATHER PATTERN
OVER THE NEXT SEVERAL DAYS. AN INCREASE TO NUMEROUS SHOWERS ARE
EXPECTED SATURDAY AND SATURDAY NIGHT AT POHNPEI AND SATURDAY THROUGH
SUNDAY AT KOSRAE. A NORTHWARD SHIFT IN THIS DEVELOPING PATTERN IS
EXPECTED TO BRING NUMEROUS SHOWERS AND ISOLATED THUNDERSTORMS EARLY
NEXT WEEK AT MAJURO.
GENTLE TO FRESH TRADES WITH OCCASIONAL STRONG GUSTS NEAR HEAVIER
SHOWERS ARE POSSIBLE OVER THE NEXT SEVERAL DAYS. COMBINED SEAS OF 5
TO 7 FEET BRIEFLY BUILD TO 6 TO 8 FEET OVER THE WEEKEND AT MAJURO, IN
RESPONSE TO AN INCREASE IN TRADE WINDS AND SWELL. NORTHERLY SWELL
CONTINUES TO CONTRIBUTE TO ELEVATED SURF ALONG NORTH-FACING REEFS OF
POHNPEI AND NORTH- AND EAST-FACING REEFS OF KOSRAE THROUGH THE
WEEKEND.
WESTERN MICRONESIA...
AN UNSETTLED PATTERN CONTINUES ACROSS FAR WESTERN MICRONESIA, WITH
SATELLITE IMAGERY THIS AFTERNOON SHOWING SCATTERED TO NUMEROUS
LOCALLY HEAVY SHOWERS BUILDING WESTWARD ACROSS PALAU AND YAP COASTAL
WATERS. CURRENT SATELLITE TRENDS FAVOR A SLIGHT DECREASE IN SHOWERS
FOR PALAU THIS EVENING AS A MORE STRATIFORM BAND MOVES OVERHEAD, BUT
A ROBUST TROUGH AND CONVERGENCE ZONE ARE SEEN JUST FURTHER EAST, DUE
SOUTH OF YAP PROPER. SHOWERS AND THUNDERSTORMS ASSOCIATED WITH THIS
FEATURE ARE EXPECTED TO BUILD WESTWARD ACROSS PALAU TONIGHT, PEAKING
AROUND MIDNIGHT. SHOWERS WILL BE LOCALLY HEAVY AT TIMES, TAPERING
OFF THROUGH SATURDAY MORNING AS DRIER AIR WORKS ITS WAY IN FROM THE
SOUTHEAST. CURRENT MODEL GUIDANCE SUGGESTS THE HEAVIEST SHOWERS WILL
SCRAPE JUST SOUTH OF YAP PROPER AS THEY MOVE THROUGH THE SOUTHERN
COASTAL WATERS, AND THE POSSIBILITY FOR LOCALLY HEAVY SHOWERS WERE
INCLUDED IN THE FORECAST FOR TONIGHT.
TO THE EAST, CHUUK SITS ON THE WESTERN EDGE OF A BROAD TRADE-WIND
TROUGH THAT EXTENDS SOUTHEAST BETWEEN WENO AND POHNPEI. SHOWERS ARE
BUILDING THIS EVENING WITHIN THE CONVERGENCE ALONG THE BACKSIDE OF
THE TROUGH, NEAR POHNPEI. AS THIS FEATURE SHIFTS WESTWARD, SCATTERED
SHOWERS WILL BUILD NEAR CHUUK THIS EVENING, WITH MODELS INDICATING
NUMEROUS LOCALLY HEAVY SHOWERS DEVELOPING LATE OVERNIGHT THROUGH
EARLY SATURDAY MORNING AS THE TROUGH STRENGTHENS AND MEANDERS
WESTWARD. A FAIRLY WET PATTERN IS THEN EXPECTED ACROSS THE REGION
THROUGH THE MIDDLE OF NEXT WEEK, AS THE TROUGH EAST OF CHUUK LOOKS TO
FORM A BROAD, HIGHLY DISORGANIZED DISTURBANCE WHICH WILL PROPAGATE
SLOWLY WEST ACROSS YAP STATE, THEN STRENGTHEN SLIGHTLY AS IT MOVES
INTO THE REPUBLIC OF PALAU AROUND WEDNESDAY.
RECENT ALTIMETRY INDICATES COMBINED SEAS AROUND 3 TO 5 FEET NEAR
PALAU AND 4 TO 6 FEET AROUND YAP AND CHUUK. SEAS WILL INCREASE
SLIGHTLY BY A FOOT OR SO OVER YAP WATERS INTO THE WEEKEND AS A PULSE
OF NORTH-NORTHEAST TO NORTHEAST SWELL MOVES THROUGH THE REGION.
GUM WATCHES/WARNINGS/ADVISORIES
GU...NONE.
MP...NONE.
MARIANAS WATERS...NONE.
MARIANAS/EAST AND WEST MICRONESIA UPDATE: WILLIAMS
MARIANAS: OGLE/MONTVILA
EAST MICRONESIA: CRUZ
WEST MICRONESIA: DECOU
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