160
FXPQ50 PGUM 272013
AFDGUM
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TIYAN GU
613 AM CHST FRI AUG 28 2026
MARIANAS UPDATE
AN UNSETTLED, BUT DISORGANIZED MONSOON PATTERN CONTINUES TO
BRING PERIODS OF SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS OVER
THE NEXT SEVERAL DAYS. OVER THE WEEKEND, WE COULD SEE ANOTHER MONSOON
SURGE LATE SATURDAY NIGHT OR SUNDAY, DEPENDING ON A MONSOON
DISTURBANCE THAT MAY FORM SOUTHEAST OF THE MARIANAS, JUST NORTH OF
CHUUK. NOTED LOCALLY HEAVY SHOWERS POSSIBLE THEN, OTHERWISE NO OTHER
CHANGES WERE MADE TO THE FORECAST. LIGHT TO MODERATE WINDS OUT OF
THE WEST TO NORTHWEST BECOME WEST-SOUTHWESTERLY EARLY NEXT WEEK.
COMBINED SEAS OF 4 TO 5 FEET WILL CONTINUE THROUGH SATURDAY NIGHT,
THEN BUILD UP TO AROUND 6 FEET EARLY NEXT WEEK DUE TO AN INCREASE IN
WESTERLY SWELL. A LOW RISK OF RIP CURRENTS IS EXPECTED TODAY, THEN
INCREASES TO MODERATE ALONG WEST- AND NORTH-FACING REEFS STARTING
TONIGHT.
TROPICAL SYSTEMS UPDATE
TROPICAL STORM ETAU (21W) IS NORTH-NORTHEAST OF WAKE ISLAND, AROUND
22N168E. ETAU IS MOVING NORTH AT 9 MPH. IT IS EXPECTED TO MAKE A
SLIGHT TURN TOWARD THE NORTH-NORTHWEST WITH A SLIGHT INCREASE IN
FORWARD SPEED THROUGH SATURDAY. WITH THIS GENERAL FORECAST TRACK,
ETAU CONTINUES TO MOVE AWAY FROM WAKE ISLAND AND EXITS THE REGION,
PASSING NORTH OF 25N LATE TONIGHT OR EARLY SATURDAY. MAXIMUM
SUSTAINED WINDS REMAIN AT 45 MPH. ETAU IS FORECAST TO INTENSIFY
THROUGH SATURDAY MORNING, THEN A WEAKENING TREND IS EXPECTED SATURDAY
NIGHT ONWARD AS IT UNDERGOES SUBTROPICAL TRANSITION. FOR MORE
INFORMATION ON TROPICAL STORM ETAU (21W), PLEASE REFER TO THE
TROPICAL CYCLONE WARNING ISSUED BY THE JOINT TYPHOON WARNING CENTER
UNDER WMO HEADER WTPN32 PGTW, OR THE TROPICAL CYCLONE PUBLIC
ADVISORY, ISSUED BY THE NATIONAL WEATHER SERVICE, UNDER WMO HEADER
WTPQ32 PGUM.
TROPICAL STORM 20W IS SOUTHWEST OF WAKE, NEAR 17N164E. 20W IS MOVING
EAST-NORTHEAST AT 10 MPH. IT IS EXPECTED TO MAKE A SLIGHT TURN
TOWARD THE NORTHEAST WITH A SLIGHT INCREASE IN FORWARD SPEED THROUGH
SATURDAY. THIS GENERAL FORECAST TRACK TAKES 20W NEAR WAKE ISLAND
LATER THIS AFTERNOON. MAXIMUM SUSTAINED WINDS HAVE INCREASED TO 50
MPH. 20W IS FORECAST TO INTENSIFY THROUGH SATURDAY, POSSIBLY BECOMING
A TYPHOON TONIGHT OR EARLY SATURDAY MORNING AS IT PASSES NORTH OF
WAKE ISLAND. FOR MORE INFORMATION ON TROPICAL STORM 20W, PLEASE
REFER TO THE TROPICAL CYCLONE WARNING ISSUED BY THE JOINT TYPHOON
WARNING CENTER UNDER WMO HEADER WTPN33 PGTW, OR THE TROPICAL CYCLONE
PUBLIC ADVISORY, ISSUED BY THE NATIONAL WEATHER SERVICE, UNDER WMO
HEADER WTPQ33 PGUM.
EASTERN MICRONESIA UPDATE
FAIRLY QUIET CONDITIONS CONTINUE ACROSS THE REGION. AN ACTIVE
MONSOON PATTERN TO THE NORTH, A BUFFER CIRCULATION TO THE SOUTH AND
BROAD DISTURBANCE EAST OF THE DATE LINE IS LEADING TO WEAK DIFFLUENT
FLOW WITH ONLY PATCHY, ISOLATED TO SCATTERED SHOWERS ACROSS POHNPEI,
KOSRAE, AND MAJURO. NO MAJOR CHANGES TO THE FORECAST. TONIGHT,
SHOWER CHANCES INCREASE TO 30-40% ACROSS POHNPEI AND KOSRAE, FROM A
SOUTHWARD CURVE IN THE MONSOON TROUGH. ALTIMETRY DATA INDICATES SEAS
ARE AROUND 4 TO 6 FEET AND SCATTEROMETRY DATA SHOWS LIGHT TO
MODERATE WESTERLY WINDS ACROSS POHNPEI AND KOSRAE AND LIGHT WINDS AT
MAJURO.
WESTERN MICRONESIA UPDATE
AN AREA OF SHOWERS AND A FEW THUNDERSTORMS ARE LINGERING OVER THE
MORNING, SO PROLONGED THE PERIOD OF SCATTERED SHOWERS AND ISOLATED
THUNDERSTORMS TODAY, BUT KEPT THE DOWNTREND TO ISOLATED SHOWERS FOR
TONIGHT. SATELLITE IMAGERY SHOWS ONLY PATCHY SHOWERS ACROSS PALAU
AND CHUUK, SO NO CHANGES TO THE FORECAST WERE MADE THERE. WINDS ARE
GENTLE TO MODERATE, OUT OF THE WEST-SOUTHWEST AND ALTIMETRY SHOWS
SEAS OF 4 TO 6 FEET ACROSS THE REGION.
PREV DISCUSSION
/ISSUED 606 PM CHST THU AUG 27 2026/
MARIANAS SYNOPSIS...
SATELLITE AND RADAR SHOW MOSTLY CLOUDY SKIES WITH SCATTERED SHOWERS
FOR TONIGHT, NONE LOOK ALL THAT HEAVY AT THIS TIME THOUGH. THERE ARE
NO BUOYS LEFT IN THE MARIANAS CURRENTLY, HOWEVER WAVE MODELS SHOW
ABOUT 4 TO 5 FOOT SEAS. TWO SEPARATE ALTIMETRY PASSES ARE IN GOOD
GENERAL AGREEMENT WITH THAT, ONE WEST OF THE MARIANAS, AND ONE EAST.
DISCUSSION...
LOOKS LIKE SCATTERED SHOWERS WILL CONTINUE MOST OF THIS WEEK WITH THE
MONSOON TROUGH STAYING NEAR OR JUST NORTH OF THE AREA. STANDARD WET
SEASON FARE (ESPECIALLY FOR DURING AN EL NINO EVENT) WITH WESTERLY
WINDS AND SCATTERED SHOWERS. LOOK FOR THIS TO CONTINUE FOR THE NEXT
WEEK, WITH LITTLE UPS AND DOWNS. THE RAIN LOOKS A BIT LESS HEAVY FOR
TONIGHT AND FRIDAY THOUGH, ESPECIALLY ON RADAR AND SATELLITE, SO WENT
AHEAD AND TOOK OUT THE LOCALLY HEAVY WORDING.
MARINE...
THE WAVE MODELS HAVE BACKED OFF ON THE PREVIOUSLY EXPECTED WAVE
HEIGHT INCREASE, NOW IT'S LARGELY FLAT THE ENTIRE PERIOD. WITHOUT
SOMETHING BIG TO STIR THE POT, WHICH CERTAINLY ISN'T HAPPENING THE
NEXT FEW DAYS, THIS SEEMS LIKELY TO CONTINUE, AND THIS IS NOW WHAT'S
IN THE FORECAST.
TROPICAL SYSTEMS...
WE HAVE TWO TROPICAL CYCLONES NOW THAT ARE RATHER CLOSE TO EACH
OTHER, SO CLOSE IN FACT THAT THEY HAVE STARTED TO ORBIT EACH OTHER IN
WHAT IS CALLED A FUJIWARA AFTER THE ONE WHO FIRST DESCRIBED IT. THE
ONLY ISLAND THEY'RE CLOSE ENOUGH TO THREATEN IS WAKE ISLAND, AND EVEN
THEN THE THREAT IS MINIMAL SINCE THEY'RE WEAK TROPICAL STORMS. WITH
TIME, THEY'RE BOTH EXPECTED TO LIFT NORTHWARD AND LEAVE MICRONESIA
THROUGH THE 25N EXIT.
FOR MORE INFORMATION ON TROPICAL STORM ETAU (21W), PLEASE REFER TO
THE TROPICAL CYCLONE WARNING ISSUED BY THE JOINT TYPHOON WARNING
CENTER UNDER WMO HEADER WTPN32 PGTW, OR THE TROPICAL CYCLONE PUBLIC
ADVISORY, ISSUED BY THE NATIONAL WEATHER SERVICE, UNDER WMO HEADER
WTPQ32 PGUM.
FOR MORE INFORMATION ON TROPICAL STORM 20W, PLEASE REFER TO THE
TROPICAL CYCLONE WARNING ISSUED BY THE JOINT TYPHOON WARNING CENTER
UNDER WMO HEADER WTPN33 PGTW, OR THE TROPICAL CYCLONE PUBLIC
ADVISORY, ISSUED BY THE NATIONAL WEATHER SERVICE, UNDER WMO HEADER
WTPQ33 PGUM.
EASTERN MICRONESIA...
MOSTLY DRY CONDITIONS ARE EXPECTED TO PERSIST ACROSS THE FORECAST
SITES THROUGH FRIDAY WITH SHOWER CHANCES TOPPING OUT AROUND 30
PERCENT. GENTLE TO MODERATE WEST TO SOUTHWEST WINDS WILL CONTINUE AT
POHNPEI FOR THE NEXT SEVERAL DAYS WHILE LIGHT TO GENTLE WINDS PERSIST
AT KOSRAE AND MAJURO. THEN, THE MONSOON TROUGH MAY ENTER ANOTHER
ACTIVE PHASE WITH SHOWER AND THUNDERSTORM CHANCES INCREASING THROUGH
THE WEEKEND, MAINLY CONCENTRATING OVER POHNPEI. ANOTHER DRY SPELL MAY
FOLLOW SHORTLY THEREAFTER THROUGH THE MIDDLE OF NEXT WEEK. COMBINED
SEAS AROUND 4 TO 6 FEET WILL PREVAIL FOR THE REST OF THE WEEK WITH
SEAS CONSISTING OF A WEST TO SOUTHWEST SWELL AT POHNPEI AND KOSRAE,
AND A NORTHEAST SWELL AT MAJURO. THE SOUTHERLY SWELLS AT KOSRAE WILL
CONTINUE TO INDUCE ELEVATED SURF ALONG SOUTH-FACING REEFS, BUT WILL
STILL REMAIN BELOW HAZARDOUS CRITERIA.
WESTERN MICRONESIA...
SATELLITE IMAGERY SHOWS SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS
ACROSS YAP STATE AND ISOLATED SHOWERS ACROSS PALAU AND CHUUK.
ALTIMETRY SHOWS COMBINED SEAS BETWEEN 4 AND 6 FEET ACROSS THE
REGION.
THE ACTIVE MONSOON PATTERN THAT BROUGHT HEAVY RAINFALL AND FLASH
FLOODING TO YAP HAS BEGUN TO SHIFT NORTHWARD, MAINLY IMPACTING THE
ISLANDS OF ULITHI AND FAIS. THESE SHOWERS AND THUNDERSTORMS ARE
EXPECTED TO CONTINUE TO SHIFT NORTHWARD OVER THE COMING DAYS WITH
DRIER CONDITIONS RETURNING TO THE REGION. SOME HEAVY RAINFALL WILL
REMAIN POSSIBLE TONIGHT, BUT OVERALL THE HEAVY RAINFALL THREAT HAS
DIMINISHED. DRY CONDITIONS WILL PREVAIL THROUGH THE WEEKEND BEFORE A
POTENTIAL MONSOON DISTURBANCE MOVES ACROSS YAP STATE EARLY NEXT
WEEK.
THE MAIN CONCERN FOR PALAU WILL BE ISOLATED SHOWERS TONIGHT ALONG A
NARROW BAND OF SURFACE CONVERGENCE. A THUNDERSTORM IS ONGOING
NEAR THE EDGE OF THE COASTAL WATERS, BUT LOWER PWATS ACROSS PALAU
GENERALLY DO NOT SUPPORT THUNDER IN THE FORECAST CLOSER TO THE
ISLANDS. PWATS BELOW 1.5 INCHES ARE SEEN SOUTH OF PALAU AND LOOK TO
MOVE INTO THE COASTAL WATERS LATE TONIGHT OR EARLY TOMORROW. THESE
DRIER CONDITIONS WILL HELP TO KEEP SHOWER CHANCES AT OR NEAR ZERO.
THE CURRENT FORECAST CALLS FOR NO SHOWERS THROUGH SUNDAY AS DRIER AIR
AND SURFACE DIVERGENCE MOVE OVER PALAU. ADDITIONALLY THE DRIER
CONDITIONS IN COMBINATION WITH 10 TO 15 KT WINDS SHOULD KEEP ISLAND
EFFECT SHOWERS FROM INITIATING. DROUGHT CONDITIONS COULD WORSEN IF A
PROLONGED DRY PERIOD ESTABLISHES ITSELF.
CHUUK WILL START THE FORECAST PERIOD QUIET WITH ISOLATED SHOWERS
EXPECTED TONIGHT AND ON FRIDAY. BY FRIDAY NIGHT, THE ACTIVE MONSOON
PATTERN LOOKS TO REORIENT ITSELF OVER CHUUK STATE BRINGING SCATTERED
SHOWERS. THIS WEEKEND, A MONSOON DISTURBANCE LOOKS TO FORM JUST
NORTH OR OVER CHUUK STATE, BRINGING NUMEROUS AND LIKELY SHOWERS AND
ISOLATED THUNDERSTORMS TO THE REGION. A SLIGHT DECREASE IN SHOWER
COVERAGE IS POSSIBLE NEXT WEEK, BUT THE ACTIVE PATTERN LOOKS TO
CONTINUE. RESIDENTS ACROSS CHUUK STATE SHOULD CONTINUE TO MONITOR
FORECAST OVER THE COMING DAYS FOR THE POTENTIAL FOR HEAVY RAINFALL
THAT COULD LEAD TO FLOODING.
COMBINED SEAS ARE BETWEEN 4 AND 6 FEET ACROSS THE REGION. SEAS LOOK
TO REMAIN BENIGN THROUGH SATURDAY NIGHT. ON SUNDAY, AN INCREASE IN
THE MONSOON WINDS LOOKS TO OCCUR OVER YAP AND CHUUK, LEADING TO
HIGHER WINDS WAVES AND A MORE DEVELOPED SWELL. AT THIS TIME,
HAZARDOUS MARINE CONDITIONS OR COASTAL CONDITIONS APPEAR UNLIKELY.
HOWEVER, CHOPPY SEAS CAN MAKE INTER-ISLAND TRAVEL DIFFICULT AT
TIMES, ESPECIALLY DURING HEAVIER SHOWERS NEAR CHUUK THIS WEEKEND.
GUM WATCHES/WARNINGS/ADVISORIES
GU...NONE.
MP...NONE.
MARIANAS WATERS...NONE.
MARIANAS/EAST AND WEST MICRONESIA/TROPICAL UPDATE: CRUZ
MARIANAS/TROPICAL: STANKO
EAST MICRONESIA: MESA
WEST MICRONESIA: WILLIAMS
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page