532
FXPQ50 PGUM 280813
AFDGUM
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TIYAN GU
613 PM CHST FRI AUG 28 2026
MARIANAS SYNOPSIS
THE MARIANAS WILL BE MOSTLY CLOUDY TONIGHT BASED ON RADAR AND
SATELLITE. SHOWERS WILL BE ISOLATED TO WIDELY SCATTERED IN THE CNMI,
WHILE THEY WILL BE NUMEROUS (ALTHOUGH NOT HEAVY) ON GUAM. COMBINED
SEAS REMAIN AROUND 4 TO 6 FEET UNTIL THE MONDAY TO WEDNESDAY TIME
FRAME, WHEN THEY COULD NUDGE UP TO BETWEEN 5 AND 7 FEET.
DISCUSSION
AN AREA OF MONSOON SHOWERS IS MOVING IN, BUT THE CLOUD TOPS ON IT
ARE WARMING. SO THE FORECAST IS FOR IT TO PETER OUT AFTER REACHING
GUAM. NOT A VERY HIGH CONFIDENCE FORECAST, SINCE IT MAY NOT EVEN
REACH GUAM. SO THE FORECAST FOR GUAM HAS NUMEROUS SHOWERS TONIGHT, A
HIGH POP LOW QPF TYPE SCENARIO, WHILE THE CNMI HAS ISOLATED. STARTING
SATURDAY, EVERYONE ADJUSTS BACK TO SCATTERED.
THERE ISN'T THAT MUCH LIGHTNING AROUND, AND THERE ISN'T THAT MUCH
POTENTIAL UNTIL YOU GET WAY BACK NEAR YAP. NEVERTHELESS, WENT WITH A
MODERATE RISK OF LIGHTNING ALL WEEK, JUST BROAD BRUSHED IT TO COVER
ANY SHORT LIVED CONVECTIVE FLARE-UPS.
MARINE
SEA HEIGHTS WILL EDGE UP A LITTLE NEXT WEEK, BUT PROBABLY ONLY A
LITTLE, UNLESS A TROPICAL CYCLONE SPINS UP MORE THAN EXPECTED OR
SOMETHING.
TROPICAL SYSTEMS
TROPICAL STORM ETAU (21W) IS LOCATED NEAR 25N167E, ABOUT 365 MILES
NORTH OF WAKE ISLAND. AS OF 0300Z, TS ETAU IS MOVING NORTH-NORTHWEST
AT 13 MPH. NEAR ITS CENTER, MAXIMUM SUSTAINED WINDS ARE 50 MPH, AND
ITS MAXIMUM SUSTAINED WAVE HEIGHT IS 20 FT, ACCORDING TO THE JOINT
TYPHOON WARNING CENTER (JTWC). IT IS EXPECTED TO MAINTAIN THIS
GENERAL COURSE AND SPEED THROUGH SATURDAY, CONTINUING TO MOVE AWAY
FROM WAKE ISLAND AND OVER OPEN OCEAN. THIS GENERAL FORECAST TRACK
COULD TAKE ETAU NORTH OF 25N AND OUT OF OUR REGION BY TONIGHT.
TROPICAL STORM BANG-LANG (20W) IS LOCATED NEAR 19N165E, ABOUT 100
MILES WEST-SOUTHWEST OF WAKE ISLAND AND MOVING NORTHEAST AT 12 MPH.
TS BANG-LANG HAS INCREASED WITH MAXIMUM SUSTAINED WINDS NEAR ITS
CENTER NOW AT 70 MPH. ITS MAXIMUM SIGNIFICANT WAVE HEIGHT IS 20 FT
ACCORDING TO THE JTWC. BANG-LANG IS FORECAST TO INTENSIFY THROUGH
SATURDAY NIGHT, POSSIBLY BECOMING A TYPHOON TONIGHT. IT WILL THEN
BEGIN TO WEAKEN AS IT STARTS SUBTROPICAL TRANSITION. IT IS EXPECTED
TO MAKE A TURN TOWARD THE NORTH-NORTHEAST WITH A SLIGHT INCREASE IN
FORWARD SPEED THROUGH SATURDAY. THIS GENERAL FORECAST TRACK WILL TAKE
BANG-LANG RATHER CLOSE TO WAKE ISLAND THIS EVENING BEFORE HEADING
OVER OPEN OCEAN TO THE NORTH.
FOR MORE INFORMATION PLEASE REFER TO BULLETINS FROM THE JOINT
TYPHOON WARNING CENTER UNDER WMO HEADERS WTPN32 PGTW AND WTPN33 PGTW
AND FROM THE NATIONAL WEATHER SERVICE UNDER WMO HEADERS WTPQ32 PGUM
AND WTPQ33 PGUM.
EASTERN MICRONESIA
SATELLITE IMAGERY DEPICTS PARTLY CLOUDY SKIES AND ISOLATED SHOWERS
ACROSS POHNPEI AND KOSRAE, AND MOSTLY CLOUDY SKIES WITH SCATTERED
SHOWERS ACROSS MAJURO, ESPECIALLY IN SOUTHERN COASTAL WATERS.
SCATTEROMETRY SHOWS GENTLE WINDS ACROSS POHNPEI, AND LIGHT TO GENTLE
WINDS OVER KOSRAE AND MAJURO. AN ACTIVE PHASE OF THE MONSOON TROUGH
IS FORECASTED THROUGH THE WEEKEND, SO SHOWER POTENTIAL TOPS OUT AT 50
PERCENT WITH ISOLATED THUNDERSTORMS FOR POHNPEI AND KOSRAE. HEAVIER
SHOWERS WITH CONVECTIVE GUSTS LOOK TO BE MORE OF A POSSIBILITY FOR
POHNPEI, SO ADDITIONAL WORDING WAS INCLUDED FOR SUNDAY. AS FOR
MAJURO, DIFFUSIVE FLOW WILL CONTINUE OVER THE ATOLLS, BRINGING LIGHT
TO GENTLE WINDS, BUT SHOWERS WILL INCREASE OVER THE WEEKEND. DRIER
WEATHER IS POSSIBLE NEXT WEEK, BUT SCATTERED SHOWERS ARE SPARSELY
INCLUDED IN THE FORECAST AS THE MONSOON TROUGH REMAINS ACTIVE
NEARBY.
ALTIMETRY AND BUOY DATA INDICATES COMBINED SEAS OF 4 TO 6 FT ACROSS
THE REGION WITH PRIMARY SWELL DIRECTIONS OUT OF THE WEST, SOUTHEAST,
AND EAST AT POHNPEI, KOSRAE, AND MAJURO, RESPECTIVELY. AS FOR KOSRAE,
SURF IS NO LONGER CONSIDERED ELEVATED ALONG SOUTH-FACING REEFS WITH
AN ESTIMATED HEIGHT OF 5 FT, SO THE HEADLINE WILL BE DISCONTINUED
FOR THE TIME-BEING. HOWEVER, THESE HEIGHTS ARE STILL CAPABLE OF A
MODERATE RISK OF RIP CURRENTS, SO BEACHGOERS SHOULD REMAIN VIGILANT
IN OR NEAR THE WATERS.
WESTERN MICRONESIA
SATELLITE IMAGERY SHOWS SCATTERED SHOWERS ACROSS CHUUK AND ISOLATED
SHOWERS ACROSS PALAU AND YAP. ALTIMETRY SHOWS COMBINED SEAS RANGING
BETWEEN 4 AND 6 FEET ACROSS THE REGION.
OVERALL, WEATHER CONDITIONS HAVE CLEARED UP SIGNIFICANTLY ACROSS
WESTERN MICRONESIA OVER THE LAST 18 HOURS. SCATTERED SHOWERS ARE
SEEN ACROSS THE SOUTHERN COASTAL WATERS OF CHUUK AND A STRAY
ISOLATED THUNDERSTORM IS OBSERVED IN THE NORTHWEST COASTAL WATERS OF
YAP. ISOLATED LIGHT SHOWERS WERE ADDED BACK INTO PALAU'S FORECAST
FOR THE NEXT FEW DAYS BASED ON SATELLITE IMAGERY SHOWING WEAK
SQUALLS MOVING ACROSS PALAU AND FURTHER UPSTREAM TO THE SOUTHWEST.
DRY CONDITIONS WILL PREVAIL ACROSS PALAU THROUGH THE PERIOD AND
ACROSS YAP THROUGH SUNDAY NIGHT. A TROPICAL DISTURBANCE MAY BRING
SCATTERED SHOWERS TO YAP NEXT WEEK, BUT SHOWER COVERAGE WILL BE
GREATLY DEPENDENT ON THE LOCATION AND ORGANIZATION OF THE
DISTURBANCE.
AN ACTIVE STRETCH IS EXPECTED ACROSS CHUUK OVER THE COMING DAYS AS A
TROPICAL DISTURBANCE DEVELOPS TO THE NORTH. LOCALLY HEAVY RAINFALL
AND GUSTY WINDS ARE EXPECTED THIS WEEKEND ACROSS CHUUK. SOME
UNCERTAINTY REMAINS ON THE DEVELOPMENT OF THIS TROPICAL DISTURBANCE
BASED ON CURRENT OBSERVATIONS, BUT MODELS ARE GENERALLY IN AGREEMENT
ON AN INCREASE IN SHOWERS AND THUNDERSTORMS. A SPECIAL WEATHER
STATEMENT MAY BE NEEDED WITHIN THE NEXT COUPLE OF FORECAST CYCLES
WHEN THE TROPICAL DISTURBANCE BEGINS TO DEVELOP. AS WE HEAD INTO NEXT
WEEK, SHOWERS AND THUNDERSTORMS WILL DECREASE IN COVERAGE, WITH
ISOLATED SHOWERS POSSIBLE BY WEDNESDAY.
MARINE CONDITIONS WILL GENERALLY BE BENIGN THROUGHOUT WESTERN
MICRONESIA. THE MAIN QUESTION IS THE DEVELOPMENT AND TRACK OF A
TROPICAL DISTURBANCE THROUGH CHUUK AND YAP STATES. ONCE THIS
DISTURBANCE BEGINS TO DEVELOP, MARINE CONDITIONS WILL BECOME CHOPPY
NEAR HEAVIER SHOWERS AND THUNDERSTORMS. MARINE CONDITIONS COULD
BECOME HAZARDOUS ACROSS CHUUK THIS WEEKEND DUE TO WIDESPREAD HEAVY
SHOWERS, AND THEN FOR YAP NEXT WEEK AS THOSE SHOWERS AND
THUNDERSTORMS SHIFT WESTWARD. AT THIS TIME, WE WILL CONTINUE TO
FORECAST CHOPPY SEAS BUT CAN'T RULE OUT THE POTENTIAL FOR SEAS
HAZARDOUS TO SMALL CRAFT.
GUM WATCHES/WARNINGS/ADVISORIES
GU...NONE.
MP...NONE.
MARIANAS WATERS...NONE.
MARIANAS: STANKO
EAST MICRONESIA/TROPICAL SYSTEMS: MESA
WEST MICRONESIA: WILLIAMS
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