197
FXPQ50 PGUM 240727
AFDGUM
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TIYAN GU
527 PM CHST MON NOV 24 2025
MARIANAS SYNOPSIS
SATELLITE AND RADAR THIS AFTERNOON REVEAL JUST A FEW SHOWERS
DRIFTING THROUGH SOUTHERN GUAM COASTAL WATERS, WITH PARTLY CLOUDY
SKIES AND LITTLE VARIATION IN THE UPSTREAM ENVIRONMENT. BUOYS AND
ALTIMETRY DATA SHOW COMBINED SEAS AROUND 7 TO 9 FEET.
DISCUSSION
THE DRY TRADE-WIND REGIME WILL CONTINUE INTO MIDWEEK. SHOWERS WILL
SEE A SLIGHT INCREASE THROUGH THE LATTER HALF OF THE WEEK, BECOMING
LOW-END SCATTERED (30 PERCENT CHANCE) ON WEDNESDAY THROUGH
THANKSGIVING DAY AS A BROAD, WEAK TROUGH CROSSES THE REGION ALONG
WITH A SMALL INFLUX IN MOISTURE. ADDITIONALLY, THE UPPER-LEVEL
PATTERN BECOMES MARGINALLY MORE SUPPORTIVE DURING THIS TIMEFRAME AS
AN UPPER-LEVEL TROUGH SHIFTS JUST SOUTH TO SOUTHEAST OF THE
MARIANAS, AND THE UPPER-LEVEL EASTERLIES STRENGTHEN, INCREASING
DIVERGENCE ALOFT. OVERALL, HOWEVER, IT WILL REMAIN A FAIRLY QUIET
PATTERN, DISRUPTED LATE IN THE WEEKEND AS A MORE ROBUST TROUGH
CROSSES THE MARIANAS, FOLLOWED BY A RETURN TO DRIER WEATHER EARLY
NEXT WEEK.
MARINE
MODERATE TO FRESH TRADE WINDS WILL PREVAIL ACROSS THE REGION
TONIGHT, GRADUALLY DIMINISHING THEREAFTER, BECOMING GENTLE TO
MODERATE THROUGH THE LATTER HALF OF THE WEEK. COMBINED SEAS OF 7
TO 9 FEET WILL GRADUALLY DECREASE BY 1 TO 2 FEET TOWARD THE END OF
THE WEEK, AS THE ELEVATED TRADE SWELL AND WIND WAVES CONTINUE TO
BECOME MORE RELAXED. ALTHOUGH SEA CONDITIONS REMAIN BELOW LEVELS
HAZARDOUS TO SMALL CRAFT, SEAS WILL REMAIN CHOPPY FOR THE NEXT FEW
DAYS, ESPECIALLY OVER EASTERN COASTAL WATERS. THE ELEVATED TRADE
SWELL WILL MAINTAIN A HIGH RIP OF RISK CURRENTS ALONG EAST FACING
REEFS OF THE MARIANAS THROUGH AT LEAST WEDNESDAY NIGHT, DECREASING IN
THE LATTER HALF OF THE WEEK. A MODERATE RIP CURRENT RISK CONTINUES
FOR NORTH FACING REEFS THROUGH THE NEXT FEW DAYS AND SOUTH FACING
REEFS THROUGH TONIGHT, AS THE TRADE SWELL AND ISLAND WRAP-AROUND
EFFECTS GRADUALLY DECREASE THIS WEEK.
EASTERN MICRONESIA
THE PATTERN ACROSS EASTERN MICRONESIA REMAINS DRIER THAN EXPECTED.
LOW-END SCATTERED SHOWERS AND A COUPLE THUNDERSTORMS ARE FOUND OVER
KOSRAE AND EAST OF POHNPEI, WITH ISOLATED SHOWERS SEEN OVER POHNPEI
AND MAJURO. POHNPEI SHOWS SEAS BETWEEN 8 AND 9 FEET, WHILE ALTIMETRY
SHOWS SEAS BETWEEN 8 AND 9.5 FEET. KOSRAE BUOY SHOWS SEAS NEAR 5
FEET.
THE INTER-TROPICAL CONVERGENCE ZONE (ITCZ) HAS RETREATED EAST OF THE
DATE LINE THIS AFTERNOON. THIS HAS RESULTED IN SHOWERS BECOMING
ISOLATED OVER MAJURO. FARTHER WEST, A WEAK TRADE-WIND TROUGH WILL
MAINTAIN SCATTERED SHOWERS WITH MAYBE A THUNDERSTORM OR TWO OVER
KOSRAE THROUGH TONIGHT AND WILL APPROACH POHNPEI THROUGH THE EVENING.
THE CONVECTION WITH THIS TROUGH WILL BE BRIEF, WITH SHOWERS BECOMING
ISOLATED TUESDAY MORNING AT BOTH POHNPEI AND KOSRAE. LATEST MODEL
GUIDANCE CONTINUES TO SHOW THE ITCZ REDEVELOPING ACROSS THE REGION
BEGINNING TUESDAY. HOWEVER, THIS HAS NOT BEEN OCCURRING AS THE MODELS
PREDICT. THEREFORE, DECIDED TO MAINTAIN SCATTERED SHOWERS AND
ISOLATED THUNDERSTORMS AT MAJURO FOR TUESDAY, BUT DUE TO THE
UNCERTAINTY OF THE ITCZ DEVELOPMENT, LOWERED POPS (PROBABILITY OF
PRECIPITATION) TO LOW-END SCATTERED, AROUND 30%, WITH ISOLATED
THUNDERSTORMS. MAINTAINED THIS FORECAST INTO THE WEEKEND, WITH A
BRIEF PERIOD OF ISOLATED SHOWERS FRIDAY. FOR POHNPEI AND KOSRAE,
BROUGHT IN LOW-END SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS
MIDWEEK, REMAINING AROUND 30% INTO THE WEEKEND. AS WITH MAJURO, THERE
WILL LIKELY BE A BRIEF PERIOD OF ISOLATED SHOWERS FRIDAY.
FOR THE MARINE FORECAST, THERE WAS ONE MAJOR CHANGE. FOR POHNPEI,
THE LATEST BUOY OBSERVATIONS SHOW SEAS BETWEEN 8 AND 9 FEET, WITH
ALTIMETRY SHOWING SEAS OF 8 TO 9.5 FEET. THIS IS A COMBINATION OF A
BUILDING NORTHEAST TRADE SWELL PRODUCED BY A TRADE-WIND SURGE TO THE
NORTHEAST COMBINED WITH A SMALL, BUT LONG-PERIOD, NORTH SWELL AND
NORTHEAST WIND WAVES. THIS COMBINATION IS EXPECTED TO PRODUCE
HAZARDOUS SURF CONDITIONS ALONG NORTH FACING REEFS OF POHNPEI THROUGH
TUESDAY AFTERNOON. THE NORTHEAST SWELL IS EXPECTED TO SUBSIDE
TUESDAY AS THE NORTH SWELL DISSIPATES, ALLOWING THE SURF TO FALL
BELOW HAZARDOUS LEVELS BY MID AFTERNOON TUESDAY. OTHERWISE, THE
MARINE FORECAST REMAINS RELATIVELY UNCHANGED.
WESTERN MICRONESIA
A NEAR-EQUATORIAL TROUGH (NET) EXTENDS EAST-SOUTHEASTWARD FROM
INVEST 92W, NEAR THE PHILIPPINES, AND PASSES SOUTH OF PALAU COASTAL
WATERS AND STRETCHES ACROSS SOUTHERN YAP AND CHUUK STATES. AN AREA
OF CONVERGENCE TRAILING INVEST 92W IS SEEN NEAR YAP AND PALAU WHICH
WILL MAINTAIN SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS THROUGH
TONIGHT FOR YAP AND THROUGH TUESDAY FOR PALAU. THEN, SHOWERS ARE
EXPECTED TO DECREASE TO ISOLATED FOR MUCH OF THE WEEK WITH A SLIGHT
UPTICK IN SHOWERS FOR YAP WEDNESDAY NIGHT AS A MINOR TRADE-WIND
TROUGH PASSES THROUGH. FARTHER EAST, RELATIVELY QUIET WEATHER IS
EXPECTED AT CHUUK OVER THE NEXT FEW DAYS WITH ONLY PATCHY, TRADE-
WIND SHOWERS EXPECTED. THEN, AN ITCZ FRAGMENT BEGINS TO EXTEND INTO
CHUUK STATE, BRINGING A MORE UNSETTLED WEATHER PATTERN IN THE LATTER
HALF OF THE WEEK.
ALTIMETRY DATA INDICATES SEAS ARE 5 TO 7 FEET AROUND PALAU AND 6 TO
9 FEET NEAR YAP AND CHUUK. MODERATE WINDS ARE EXPECTED TONIGHT FOR
YAP AND CHUUK, DECREASING TO LIGHT TO MODERATE FOR THE REST OF THE
WEEK. AT PALAU, SLIGHTLY WEAKER WINDS ARE EXPECTED DUE TO BEING
CLOSER TO THE NET AXIS. LIGHT TO GENTLE WINDS ARE EXPECTED FOR THE
NEXT SEVERAL DAYS, BRIEFLY BECOMING GENTLE TO MODERATE WEDNESDAY
NIGHT. SURF ALONG NORTH-FACING REEFS OF CHUUK MAY STILL BE A BIT
ELEVATED TONIGHT UNTIL PRIMARY NORTHEAST TRADE SWELL AND LONG-PERIOD
NORTH SWELL GRADUALLY DIMINISHES OVER THE NEXT FEW DAYS. THIS
DECREASE IN WIND WAVES WILL ALSO CAUSE COMBINED SEAS TO DECREASE TO
4 TO 6 FEET IN THE LATTER HALF OF THE WEEK.
GUM WATCHES/WARNINGS/ADVISORIES
GU...HIGH RIP CURRENT RISK THROUGH LATE WEDNESDAY NIGHT FOR GUZ001.
MP...HIGH RIP CURRENT RISK THROUGH LATE WEDNESDAY NIGHT FOR MPZ001>003.
MARIANAS WATERS...NONE.
MARIANAS: DECOU
EAST MICRONESIA: KLEESCHULTE
WEST MICRONESIA: CRUZ
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