341
FXPQ50 PGUM 221759
AFDGUM
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TIYAN GU
359 AM CHST THU APR 23 2026
MARIANAS UPDATE
NO CHANGES WERE NEEDED AS THE TRADE PATTERN REMAINS QUIET. WINDS ARE
SLIGHTLY HIGHER THAN USUAL THIS MORNING, AND WE CAN EXPECT THEM TO BE
SIMILAR VALUES FOR THE AFTERNOON AS YESTERDAY, IF NOT A TOUCH HIGHER.
EASTERN MICRONESIA UPDATE
THE MAIN FORECAST CHALLENGE WAS RAINFALL POTENTIAL. FOR POHNPEI AND
KOSRAE, WE REDUCED SHOWER COVERAGE TO ISOLATED TODAY BASED ON WEAK
CONVERGENCE AND SATELLITE TRENDS. AT MAJURO AS YOU'RE JUST NORTH OF
THE DEEPER MOISTURE AND CONVERGENCE. WITH THAT SAID, IT'S CLOSE
ENOUGH TO WARRANT KEEPING THE FORECAST THAT WAS INHERITED.
WESTERN MICRONESIA UPDATE
THE MAIN CHANGE HERE WAS TO REDUCE RAINFALL POTENTIAL SOME FOR TODAY,
AS POPS (PROBABILITY OF PRECIPITATION) LOOKED A LITTLE HIGH COMPARED
TO SATELLITE IMAGERY. A SUBTLE TROUGH TO THE EAST MAY MAKE IT INTO
THE AREA TONIGHT TO MATCH THE FORECAST, BUT, SUSPECT IT MAY BE
AROUND OR AFTER MIDNIGHT. TEMPERATURES WERE ADJUSTED DOWNWARD A
COUPLE OF DEGREES TODAY AT PALAU, AS IT ALSO LOOKED A TOUCH WARM
COMPARED TO OBSERVATIONS YESTERDAY. OTHERWISE, NO ADDITIONAL CHANGES
WERE NEEDED.
PREV DISCUSSION
/ISSUED 527 PM CHST WED APR 22 2026/
MARIANAS SYNOPSIS...
PARTLY CLOUDY SKIES WITH ISOLATED SHOWERS CONTINUE ACROSS THE MARIANAS
FOR THE REMAINDER OF THE WEEK. INCREASED SHOWERS AND STRENGTHENING
TRADE WINDS ARE POSSIBLE EARLY NEXT WEEK. BUOYS SHOW SEAS ARE 4 TO 6
FEET.
DISCUSSION...
A DISSOLVING FRONTAL BOUNDARY EXISTS EAST OF GUAM AND IS ADVECTING
WEST WITH THE TRADE WINDS, BUT THE DRY REGIME WILL KEEP ISOLATED
SHOWERS AND PARTLY CLOUDY SKIES OVER THE MARIANAS FOR THE REMAINDER
OF THE WEEK. OVER THE WEEKEND, A HIGH PRESSURE CELL COULD TRAVERSE
EASTWARD FROM JAPAN ACROSS THE MID-LATITUDES, SO THE POSSIBILITY OF
MODERATE TO FRESH TRADE WINDS HAS REMAINED DUE TO THE STRONGER
PRESSURE GRADIENT. ADDITIONALLY, MODEL GUIDANCE SHOWS A TROUGH MOVING
IN FROM THE EAST, POSSIBLY BRINGING LOW-END SCATTERED SHOWERS TO THE
MARIANAS EARLY NEXT WEEK.
MARINE...
COMBINED SEAS OF 4 TO 6 FEET ARE EXPECTED TO INCREASE A FOOT
THURSDAY BEFORE TAPERING BACK DOWN THEREAFTER. SEAS ARE LIKELY TO
PERSIST UNTIL EARLY NEXT WEEK, ONCE SEAS BEGIN TO INCREASE AGAIN DUE
TO STRENGTHENING TRADE SWELL AND LOCALIZED WIND WAVES. A MODERATE RISK
OF RIP CURRENTS IS EXPECTED ALONG NORTH AND EAST FACING REEFS OF THE
MARIANAS FOR AT LEAST THE NEXT SEVERAL DAYS. SURF IS EXPECTED TO
PERSIST AT CURRENT LEVELS UNTIL EARLY NEXT WEEK, WHEN IT MAY INCREASE
AN AND ADDITIONAL FEW FEET ALONG NORTH AND EAST FACING REEFS ONCE THE
AFOREMENTIONED SWELL AND WIND WAVES INCREASE.
EASTERN MICRONESIA...
TROUGHING WILL CONTINUE TO IMPACT KOSRAE AND POHNPEI THROUGH TONIGHT,
BRINGING PERIODS OF SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS.
CONDITIONS SHOULD BRIEFLY IMPROVE ON THURSDAY AND CONTINUE INTO FRIDAY,
WITH ONLY ISOLATED TO LOW-END SCATTERED SHOWERS AND SOME THUNDERSTORMS
EXPECTED AS A TRADE-WIND PATTERN DEVELOPS ACROSS EASTERN MICRONESIA.
NORTHEAST TO EAST WINDS WILL INCREASE STARTING LATE THURSDAY AS THE
PRESSURE GRADIENT TIGHTENS. MODERATE TO FRESH WINDS WILL BE POSSIBLE
AT ALL FORECAST POINTS FROM FRIDAY THROUGH THE WEEKEND WITH THE
STRONGEST WINDS AT MAJURO. SHOWER CHANCES WILL INCREASE STARTING LATE
ON FRIDAY AS THE ITCZ SHIFTS NORTHWARD AND A SERIES OF TRADE-WIND
TROUGHS MOVE THROUGH THE REGION. SCATTERED TO LOW-END NUMEROUS
SHOWERS AND ISOLATED THUNDERSTORMS CAN BE EXPECTED THIS WEEKEND.
THE COASTAL WATERS OF POHNPEI AND KOSRAE CONSIST OF A LONGER-PERIOD
NORTH SWELL AND A DIMINISHING, LONGER-PERIOD NORTHWEST SWELL.
ELEVATED SURF WILL CONTINUE TO BE POSSIBLE ALONG NORTH-FACING REEFS
OF BOTH KOSRAE AND POHNPEI THROUGH TONIGHT. SEAS AROUND MAJURO
CONSISTS OF THE LONGER-PERIOD NORTH SWELL AND A SHORT-PERIOD EAST
SWELL. COMBINED SEAS OF 4 TO 6 FEET WILL INCREASE BY A FOOT OR TWO AT
ALL SITES THROUGH THE WEEKEND AS A TRADE SWELL BUILDS INTO EASTERN
MICRONESIA STARTING WITH THE MARSHALL ISLANDS. ELEVATED TO POSSIBLY
HAZARDOUS SURF WILL BE POSSIBLE AT POHNPEI AND KOSRAE THIS WEEKEND AS
THE TRADE SWELL BUILDS. SEAS UP TO 8 FEET WILL BE POSSIBLE AT MAJURO
THIS WEEKEND.
WESTERN MICRONESIA...
THE LEADING EDGE OF THE OF THE ITCZ FRAGMENT WITH EMBEDDED TROUGHS IS
MOVING INTO CHUUK STATE. THIS FEATURE WILL BRING AN UNSETTLED WEATHER
PATTERN TO CHUUK THROUGH EARLY NEXT WEEK. SCATTERED SHOWERS AND
ISOLATED THUNDERSTORMS ARE EXPECTED THROUGH THIS TIME FRAME.
ESTIMATED RAIN FALL TOTALS ARE EXPECTED TO BE WITHIN THE RANGE OF 0.5
TO 1.0 INCHES PER DAY THROUGH THE BEGINNING OF NEXT WEEK.
OVER IN YAP AND PALAU, A DRIER REGIME HAS SET UP AND IS EXPECTED TO
REMAIN FOR THE NEXT DAY OR SO. THEN, SHOWERS ARE EXPECTED TO RETURN
AROUND THURSDAY NIGHT TO FRIDAY AS FEW TROUGHS MAKE THEIR WAY ACROSS
EASTERN YAP STATE. THESE SHOWERS MAY REMAIN IN THE AREA THROUGH THE
WEEKEND.
ALTIMETRY SHOWS COMBINED SEAS OF 4 TO 7 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: MESA/MONTVILA
EAST MICRONESIA: WHISNANT
WEST MICRONESIA: BOWSHER
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