278
FXPQ50 PGUM 211820
AFDGUM
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TIYAN GU
420 AM CHST WED APR 22 2026
MARIANAS UPDATE
THE GOING FORECAST REMAINS IN GOOD SHAPE WITH NO SIGNIFICANT UPDATES
NEEDED. A FEW SHOWERS DID POP UP THIS MORNING WITH OUR NOCTURNAL
BUMP, AND WE DID GET A BRIEF SHOWER HERE AT THE AIRPORT, BUT THESE
SHOULD FIZZLE OUT SHORTLY AFTER SUNRISE.
EASTERN MICRONESIA UPDATE
THE MAIN UPDATE WAS TO INCREASE RAINFALL PROBABILITIES SLIGHTLY TO 40
PERCENT FOR TODAY AT BOTH POHNPEI AND KOSRAE GIVEN SATELLITE TRENDS.
HEADLINES FOR ELEVATED NORTH SURF AT BOTH LOCATIONS WERE ALSO
RETAINED. OTHERWISE, NO SIGNIFICANT CHANGES WERE NEEDED.
WESTERN MICRONESIA UPDATE
THE GOING FORECAST IS IN GREAT SHAPE. PALAU AND YAP WILL SEE WARM
AFTERNOON TEMPERATURES GIVEN LIGHT WINDS AND MAINLY CLOUD-FREE SKIES.
WETTER WEATHER HAS DEPARTED CHUUK BUT A NEARBY ELEVATED DISTURBANCE
MAY ALLOW FOR A DIURNAL INCREASE LATER TODAY.
PREV DISCUSSION
/ISSUED 455 PM CHST TUE APR 21 2026/
MARIANAS SYNOPSIS...
SATELLITE AND RADAR OBSERVATIONS SHOW MOSTLY CLOUDY SKIES WITH
ISOLATED SHOWERS ACROSS GUAM, AND PARTLY CLOUDY SKIES ACROSS THE
CNMI. ALTIMETRY AND BUOY DATA SHOW COMBINED SEAS BETWEEN 3 AND 6
FEET ACROSS THE MARIANAS.
DISCUSSION...
DRY CONDITIONS CONTINUE ACROSS THE MARIANAS AS THE SEASONAL DOLDRUMS
REMAIN OVER THE REGION. A FEW ISOLATED SHOWERS ARE SEEN EAST OF GUAM,
BUT THESE HAVE STRUGGLED TO MAKE IT ON LAND WITH LITTLE TO NO
RAINFALL SEEN ACROSS THE ISLAND TODAY. A TRADE-WIND SURGE WILL MOVE
INTO THE REGION THIS WEEKEND BRINGING MODERATE TO FRESH WINDS. AS THE
TRADES BUILD, SHOWERS MAY INCREASE IN COVERAGE WHEN TRADE-WIND
CONVERGENCE OCCURS. AS OF NOW THE FORECAST KEEPS ISOLATED SHOWERS IN
THE EXTENDED RANGE, BUT THERE WILL BE SOME POTENTIAL FOR SHORT
PERIODS OF SCATTERED SHOWERS NEXT WEEK.
MARINE...
BENIGN MARINE CONDITIONS OF 3 TO 6 FEET WILL CONTINUE UNTIL FRIDAY
WHEN SEAS BEGIN TO RISE DUE TO INFLUENCE FROM A TRADE-WIND SURGE.
COMBINED SEAS LOOK TO BRIEFLY RISE TO 6 TO 8 FEET THURSDAY NIGHT INTO
FRIDAY, BEFORE A SHORT DROP IN SEAS THIS WEEKEND AND ANOTHER RISE
HEADING INTO MONDAY. THERE WILL BE A MODERATE RISK FOR RIP CURRENTS
ALONG NORTH AND EAST FACING REEFS THROUGH FRIDAY WITH A LOW RISK FOR
RIP CURRENTS ACROSS SOUTH AND WEST FACING REEFS THROUGH THE WEEK.
EASTERN MICRONESIA...
A TRADE-WIND TROUGH WILL CONTINUE TO BRING SCATTERED SHOWERS AND
ISOLATED THUNDERSTORMS TO PORTIONS OF WESTERN POHNPEI STATE DURING
THE NEXT 24-HOURS AS IT SLOWLY PROGRESSES WESTWARD. ISOLATED TO LOW-
END SCATTERED SHOWERS AND THUNDERSTORMS ARE EXPECTED TO PREVAIL AT
ALL THREE FORECAST POINTS TONIGHT AND WEDNESDAY. A TRADE-WIND PATTERN
WILL DEVELOP STARTING ON THURSDAY WITH A SERIES OF TRADE-WIND
TROUGHS EXPECTED TO MOVE ACROSS EASTERN MICRONESIA FROM FRIDAY
THROUGH THE WEEKEND AS THE ITCZ REBUILDS. WET AND UNSETTLED WEATHER
WITH SCATTERED TO LOW-END NUMEROUS SHOWERS AND ISOLATED
THUNDERSTORMS ARE POSSIBLE ACROSS EASTERN MICRONESIA DURING THIS
TIMEFRAME. EAST TO NORTHEAST WINDS WILL DEVELOP ON THURSDAY AND
BECOME MODERATE TO FRESH AT ALL THREE FORECAST POINTS THROUGH THE
WEEKEND AS THE PRESSURE GRADIENT TIGHTENS.
SEAS OF KOSRAE AND POHNPEI CONSIST OF A LONGER-PERIOD NORTH SWELL
AND A SMALL, LONGER-PERIOD NORTHWEST SWELL WHILE THE COASTAL WATERS
OF MAJURO CONSIST OF THE LONGER-PERIOD NORTH SWELL AND A LINGERING
SHORTER-PERIOD EAST SWELL. ELEVATED SURF WILL BE POSSIBLE ALONG
NORTH-FACING REEFS OF BOTH KOSRAE AND POHNPEI THROUGH WEDNESDAY
GIVEN THE LONGER-PERIOD NORTH SWELL. COMBINED SEAS OF 4 TO 6 FEET
WILL SLOWLY SUBSIDE THROUGH WEDNESDAY BEFORE A NORTHEAST, TRADE SWELL
BUILDS INTO EASTERN MICRONESIA STARTING LATE ON FRIDAY. COMBINED
SEAS OF 4 TO 7 FEET CAN BE EXPECTED BY FRIDAY AND THROUGH THE WEEKEND
AT POHNPEI AND KOSRAE WITH SEAS REACHING 8 FEET AT MAJURO.
WESTERN MICRONESIA...
THE MAIN WEATHER MAKER IS A FEW TRADE-WIND TROUGHS MOVING THROUGH
CHUUK STATE. THESE TROUGHS ARE EXPECTED TO PRODUCE SCATTERED SHOWERS
THROUGHOUT CHUUK STATE AND IS EXPECTED TO GRADUALLY MOVE WESTWARD
OVER THE NEXT DAY OR TWO. THE NEXT FEATURE TO MOVE INTO THIS REGION
IS ANTICIPATED TO BE ANOTHER SECTION OF THE ITCZ WITH MORE EMBEDDED
TROUGHS IN THE LATTER HALF OF THE WEEK. THIS IS ANTICIPATED TO BRING
MORE SCATTERED SHOWERS TO THE REGION. OVERALL A WET WEEK IS IN STORE
FOR CHUUK.
OVER IN YAP AND PALAU, A DRY PATTERN REGIME HAS SET UP AND IS EXPECTED
TO REMAIN THROUGH MUCH OF THE WEEK. SHOWERS MAY RETURN NEAR THE END
OF THE WEEK AS THE TROUGHS IN CHUUK STATE MAKE THEIR WAY WESTWARD.
ALTIMETRY SHOWS COMBINED SEA OF 5 TO 6 FEET ACROSS THE REGION. WINDS
ARE EXPECTED TO BE LIGHT TO MODERATE THROUGH THE WEEKEND. OVERALL
FAIRLY BENIGN SEAS ARE EXPECTED.
GUM WATCHES/WARNINGS/ADVISORIES
GU...NONE.
MP...NONE.
MARIANAS WATERS...NONE.
MARIANAS/EAST AND WEST MICRONESIA UPDATE: DOLL
MARIANAS: WILLIAMS
EAST MICRONESIA: WHISNANT
WEST MICRONESIA: BOWSHER
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