960
FXPQ50 PGUM 300141
AFDGUM
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TIYAN GU
1141 AM CHST SUN AUG 30 2026
UPDATE
CONVECTION WILL REMAIN ISOLATED ACROSS THE MARIANAS THE REMAINDER OF
TODAY.
PREV DISCUSSION
/ISSUED 555 AM CHST SUN AUG 30 2026/
MARIANAS UPDATE...
SCATTERED TO NUMEROUS SHOWERS AND ISOLATED THUNDERSTORMS ARE
EXPECTED THROUGH TONIGHT AND INTO EARLY THIS WEEK, WITH THE HIGHEST
SHOWER CHANCES BEING FOR GUAM. DID INCREASE SHOWER CHANCES TODAY AND
TONIGHT FOR GUAM TO 60 PERCENT WITH LOCALLY HEAVY SHOWERS POSSIBLE.
GENTLE TO MODERATE NORTHWEST WINDS WILL EASE SLIGHTLY STARTING
TONIGHT AND BECOME LIGHT TO GENTLE SOUTH TO SOUTHWEST WINDS BY MONDAY
NIGHT. COMBINED SEAS OF 4 TO 5 FEET WILL CONTINUE INTO MONDAY WITH
SEAS BUILDING A FOOT OR TWO THEREAFTER AS A WEST SWELL MOVES IN.
OTHERWISE, A MODERATE RISK OF RIP CURRENTS WILL CONTINUE ALONG NORTH-
AND WEST-FACING REEFS THROUGH AT LEAST MONDAY WITH THE POTENTIAL A
HIGH RISK TO DEVELOP ALONG WEST-FACING REEFS AROUND MIDWEEK AS A WEST
SWELL BUILDS IN.
TROPICAL SYSTEMS UPDATE...
TYPHOON BANG-LANG EXITED NWS GUAM'S AREA OF RESPONSIBILITY LATE
YESTERDAY EVENING AS IT CROSSED 25N. BANG-LANG IS CURRENTLY MOVING TO
THE NORTH AROUND 15 MPH AND IS EXPECTED TO MAKE A SLIGHT TURN TO THE
NORTH-NORTHWEST AS IT INCREASES IN FORWARD SPEED THROUGH MONDAY. FOR
MORE INFORMATION ON TYPHOON BANG-LANG, PLEASE SEE BULLETINS ISSUED
BY THE JOINT TYPHOON WARNING CENTER (JTWC) UNDER WMO HEADER WTPN33
PGTW.
INVEST 94W WAS OPENED YESTERDAY EVENING AND WAS UPGRADED TO A MEDIUM
BY JTWC LATE YESTERDAY EVENING. THIS MEANS THAT FORMATION INTO A
SIGNIFICANT TROPICAL CYCLONE (TROPICAL DEPRESSION) IS LIKELY, BUT
EXPECTED TO OCCUR BEYOND 24 HOURS. 94W IS LOCATED AROUND 20N135E THIS
MORNING AND ENSEMBLE GUIDANCE SUGGESTS THAT THE INVEST WILL
GENERALLY MOVE TO THE NORTHWEST OVER THE COMING DAYS AS IT DEVELOPS.
FOR MORE INFORMATION ON INVEST 94W, PLEASE SEE BULLETINS ISSUED BY
JTWC UNDER WMO HEADER ABW10 PGTW.
EASTERN MICRONESIA UPDATE...
OVERNIGHT SATELLITE IMAGERY SHOWS SHOWERS AND THUNDERSTORMS AT LEAST
IN THE VICINITY OF ALL THREE SITES, WITH ACTIVE CONVECTION OVER
POHNPEI. HAVE KEPT SCATTERED TO NUMEROUS SHOWERS AND ISOLATED
THUNDERSTORMS IN THE FORECAST THROUGH TONIGHT FOR ALL SITES, TOPPING
OUT AT 60 PERCENT FOR POHNPEI. LOCALLY HEAVY RAINFALL WILL BE
POSSIBLE AT POHNPEI THROUGH TONIGHT WITH SOME GUSTS TO 25 KNOTS
EXPECTED NEAR HEAVIER SHOWERS AND THUNDERSTORMS. GENTLE TO MODERATE
SOUTHWEST WINDS WILL CONTINUE THROUGH TODAY AT BOTH KOSRAE AND
POHNPEI WITH KOSRAE LIKELY EASING TO ONLY GENTLE STARTING TONIGHT.
WINDS WILL BE GENERALLY LIGHT AT MAJURO THROUGH EARLY THIS WEEK.
COMBINED SEAS OF 4 TO 6 FEET WILL CONTINUE THROUGH TONIGHT BEFORE
DROPPING A FOOT OR SO STARTING ON MONDAY.
WESTERN MICRONESIA UPDATE...
YESTERDAY EVENING'S SCATTEROMETRY PASS SHOWED WINDS LIKELY MEETING
SMALL CRAFT ADVISORY CRITERIA (SUSTAINED WINDS OF 22 KNOTS) IN THE
COASTAL WATERS OF CHUUK. A SMALL CRAFT ADVISORY WAS ISSUED OVERNIGHT
TO COVER THE THREAT AND IS IN EFFECT THROUGH 5 PM MONDAY AS MODERATE
TO FRESH SOUTHWEST WINDS WILL CONTINUE THROUGH THIS PERIOD. GUSTS UP
TO 30 KNOTS WILL BE POSSIBLE. WET AND UNSETTLED WEATHER WILL
CONTINUE AT CHUUK THROUGH AT LEAST MONDAY WITH LOCALLY HEAVY RAINFALL
POSSIBLE. DRIER CONDITIONS ARE EXPECTED TO PREVAIL AT PALAU AND YAP
THROUGH AT LEAST TONIGHT FOR YAP, WITH SHOWER CHANCES LIKELY RAMPING
UP ON MONDAY. GENTLE TO MODERATE WEST TO SOUTHWEST WINDS WILL
CONTINUE THROUGH EARLY THIS WEEK AT YAP AND PALAU. COMBINED SEAS OF 3
TO 5 FEET WILL BUILD AROUND TWO FEET OR SO STARTING TONIGHT AT PALAU
AND YAP AS A WEST SWELL MOVES IN. COMBINED SEAS OF 7 TO 8 FEET ARE
EXPECTED AT CHUUK, WITH LOCALLY CHOPPY SEAS POSSIBLE, AND WILL
CONTINUE INTO MONDAY. OTHERWISE, ELEVATED SURF ALONG WEST-FACING
REEFS AT YAP WILL BE POSSIBLE STARTING MONDAY, POTENTIALLY REACHING
HAZARDOUS LEVELS MONDAY NIGHT.
PREV DISCUSSION... /ISSUED 601 PM CHST SAT AUG 29 2026/
MARIANAS SYNOPSIS...
PARTLY CLOUDY SKIES WITH ISOLATED SHOWERS AND LIGHT TO GENTLE WINDS
PREVAIL ACROSS THE MARIANAS THIS AFTERNOON. LATEST ALTIMETRY DATA
SHOWS SEAS BETWEEN 3 AND 4 FEET.
DISCUSSION...
A MUCH DRIER REGIME HAS MOVED IN OVER THE MARIANAS THIS AFTERNOON.
HOWEVER, THE MONSOON PATTERN STILL SUPPORTS THE DEVELOPMENT OF
SCATTERED SHOWERS ACROSS THE REGION LATER THIS EVENING NEAR MIDNIGHT.
LATEST MODEL GUIDANCE INDICATES A DRIER PATTERN THAN PREVIOUSLY
EXPECTED. THIS HAS RESULTED IN DECREASED POPS (PROBABILITY OF
PRECIPITATION) OVER THE NEXT SEVERAL DAYS. PERIODS OF LOCALLY HEAVY
SHOWERS, ALONG WITH GUSTY WINDS IN HEAVIER SHOWERS, REMAIN A
POSSIBILITY THROUGH SUNDAY, THOUGH IT DOES NOW LOOK LESS LIKELY.
MARINE/SURF...
NOT MUCH GOING ON IN THE MARINE ENVIRONMENT OVER THE NEXT FEW DAYS.
BENIGN SEAS AND LIGHT TO GENTLE WINDS WILL PERSIST THROUGH TUESDAY.
SEAS WILL MAINTAIN A MODERATE RISK OF RIP CURRENTS ALONG WEST AND
NORTH FACING REEFS. NEXT WEEK, SEAS WILL BEGIN TO BUILD EARLY IN THE
WEEK, REACHING UP TO 8 FEET BY THURSDAY. THIS COULD BRING THE RIP
CURRENT RISK TO MODERATE ALONG EAST FACING REEFS AND POSSIBLY HIGH
ALONG WEST FACING REEFS. WINDS WILL BECOME OCCASIONALLY MODERATE
AROUND THE MIDDLE OF NEXT WEEK.
TROPICAL SYSTEMS...
AS OF EARLIER THIS AFTERNOON, TYPHOON BANG-LANG (20W) WAS LOCATED
NEAR 23N168E RAPIDLY MOVING NORTH-NORTHEAST AT 22 MPH. MAXIMUM
SUSTAINED WINDS REMAIN AT 75 MPH AND IS FORECASTED TO INTENSIFY
THROUGH TONIGHT. BANG-LANG'S WIND FIELD REMAINS COMPACT, WITH
TYPHOON-FORCE WINDS EXTENDING OUTWARD FROM THE CENTER UP TO 10
MILES AND TROPICAL STORM-FORCE WINDS UP TO 50 MILES. IT IS EXPECTED
TO MAKE A SLIGHT TURN TOWARD THE NORTH WITH LITTLE CHANGE IN FORWARD
SPEED THROUGH SUNDAY. THIS GENERAL FORECAST TRACK WILL CONTINUE
TAKING BANG-LANG AWAY FROM WAKE ISLAND, PASSING NORTH OF 25N AND OUT
OF OUR REGION POSSIBLY LATER TONIGHT OR EARLY SUNDAY MORNING.
FOR MORE INFORMATION ON TY BANG-LANG, PLEASE SEE BULLETINS ISSUED BY
THE JOINT TYPHOON WARNING CENTER UNDER WMO HEADER WTPN33 PGTW AND
BY THE NATIONAL WEATHER SERVICE UNDER WMO HEADER WTPQ33 PGUM.
EASTERN MICRONESIA...
SATELLITE IMAGERY DEPICTS MOSTLY CLOUDY SKIES AND SCATTERED SHOWERS
ACROSS ALL THREE FORECAST POINTS. SCATTEROMETRY INDICATES GENTLE TO
MODERATE WINDS ACROSS POHNPEI, AND LIGHT TO GENTLE WINDS OVER KOSRAE
AND MAJURO. AN ACTIVE PHASE OF THE MONSOON TROUGH IS FORECASTED
THROUGH THE WEEKEND, MORESO CONCENTRATED OVER POHNPEI AS THE TROUGH
SHIFTS WESTWARD OVER THE NEXT FEW DAYS. HEAVIER SHOWERS WITH
CONVECTIVE GUSTS ARE MOST LIKELY FOR POHNPEI, SO A HEADLINE AND
ADDITIONAL WORDING WAS INCLUDED THROUGH SUNDAY NIGHT. KOSRAE IS
CURRENTLY IN A DRIER SLOT, BUT OUTFLOW BOUNDARIES UPSTREAM AND
COOLING CLOUD TOPS JUST TO THE NORTH WARRANTED HIGH-END SCATTERED
SHOWERS AND ISOLATED THUNDERSTORMS FOR TONIGHT, PEAKING TO NUMEROUS
ON SUNDAY, BEFORE DECREASING THROUGH THE REST OF THE WEEK. AS FOR
MAJURO, DIFFUSIVE FLOW WILL CONTINUE OVER THE ATOLLS, MAINTAINING
LIGHT TO GENTLE WINDS, BUT SHOWERS WILL REMAIN SCATTERED WITH
ISOLATED THUNDERSTORMS POSSIBLE THROUGH THE WEEKEND. THEN, THERE IS
POTENTIAL FOR DRIER WEATHER ACROSS THE ENTIRE REGION, WITH ISOLATED
SHOWERS FORECASTED DURING THE WORK WEEK.
ALTIMETRY AND BUOY DATA INDICATES COMBINED SEAS OF 4 TO 6 FT ACROSS
THE REGION WITH PRIMARY SWELL DIRECTIONS OUT OF THE WEST, SOUTH, AND
EAST AT POHNPEI, KOSRAE, AND MAJURO, RESPECTIVELY. AT POHNPEI, THOSE
WITH MARINE INTERESTS SHOULD CONSIDER THE ELEVATED WINDS WITH
CONVECTIVE MODERATE GUSTS THROUGH THE WEEKEND. AT THIS TIME, SEA
CONDITIONS ARE NOT EXPECTED TO BE HAZARDOUS TO SMALL CRAFT, BUT THIS
COULD CHANGE DEPENDING ON THE INTENSITY AND DURATION OF THE MONSOON
TROUGH.
WESTERN MICRONESIA...
SATELLITE IMAGERY SHOWS SCATTERED SHOWERS ACROSS CHUUK AND ISOLATED
SHOWERS ACROSS PALAU AND YAP. ALTIMETRY SHOWS COMBINED SEAS ARE
BETWEEN 3 AND 6 FEET ACROSS THE REGION.
THE FORECAST REMAINS STATUS QUO FOR PALAU. DRY CONDITIONS LOOK TO
PREVAIL THROUGH THE PERIOD AND BEYOND. DROUGHT CONCERNS ARE GROWING
AS THE FAVORABLE RAIN PATTERN REMAINS NORTH OF PALAU. FOR NOW,
ISOLATED LIGHT SHOWERS REMAIN IN THE FORECAST WITH SATELLITE STILL
SHOWING WEAK SQUALLS MOVING ACROSS THE REGION. PWAT VALUES ARE
GENERALLY BETWEEN 1.5 INCHES AND 1.75 INCHES, SO ACCUMULATIONS FROM
THESE SHOWERS ARE EXPECTED TO BE BELOW THE 0.20 INCHES WETTING RAIN
THRESHOLD.
YAP WILL BEGIN THE PERIOD EQUALLY AS DRY AS PALAU. PWATS HAVE FALLEN
BELOW 2.00 INCHES OVER THE LAST DAY AND DRIER AIR WILL CONTINUE TO
MIX IN FROM THE SOUTHWEST. THIS BRIEF DRY STRETCH WILL COME TO AN END
BY MONDAY AS THE MONSOON PATTERN LOOKS TO RE-ORIENT ITSELF. HIGH-END
(50%) SCATTERED SHOWERS WILL BE POSSIBLE MONDAY THROUGH TUESDAY
NIGHT BEFORE A SLIGHT DECREASE IN SHOWER COVERAGE TO 40% IS
POSSIBLE. CONDITIONS LOOK TO DRY OUT ONCE AGAIN BEYOND THURSDAY NEXT
WEEK.
A DIFFICULT FORECAST IS IN STORE FOR CHUUK THROUGH THE WEEKEND.
GUIDANCE CONTINUES TO HIT THEM HARD WITH SHOWERS AND THUNDERSTORMS
OVER THE NEXT 36 TO 48 HOURS. A WEAK TROPICAL DISTURBANCE IS
OBSERVED NORTH OF CHUUK, BUT CURRENT SATELLITE DEPICTION DOES NOT
SUPPORT THE CURRENT FORECAST. THAT SAID, MODELS ARE ADAMANT THAT
CONVECTION WILL EXPLODE LATE TONIGHT OR EARLY SUNDAY MORNING,
BRINGING HEAVY SHOWERS AND ISOLATED THUNDERSTORMS TO CHUUK.
UNCERTAINTY REMAINS HIGH DUE TO CURRENT SATELLITE TRENDS. FOR NOW,
WE DECIDED NOT TO ISSUE A SPECIAL WEATHER STATEMENT, BUT WE HAVE
MAINTAINED THE HEADLINES FOR HEAVY RAIN AND GUSTY WINDS. BY THE
MIDDLE OF NEXT WEEK, THE ACTIVE PATTERN LOOKS TO SHIFT NORTHWARD
WITH A LOW-LEVEL RIDGE SETTING UP ACROSS CHUUK STATE. THIS RIDGE
WILL HELP KEEP SHOWERS AND THUNDERSTORMS TO ISOLATED COVERAGE.
THE MARINE FORECASTS FOR CHUUK AND YAP ARE ALSO COMPLICATED DUE TO
POTENTIAL TROPICAL DISTURBANCES NEARBY. FOR PALAU, BENIGN MARINE
CONDITIONS WILL CONTINUE THROUGH THE PERIOD. COMBINED SEAS WILL
GENERALLY BE BETWEEN 4 AND 6 FEET THROUGH THURSDAY FOR PALAU. THE
MAIN CHALLENGE FOR CHUUK IS WHETHER THE TROPICAL DISTURBANCE
ORGANIZES THIS WEEKEND OR NOT. IF THE STORM DOES NOT COME TOGETHER,
THEN BENIGN MARINE CONDITIONS WILL PREVAIL AT CHUUK. HOWEVER, IF THE
TROPICAL DISTURBANCE ORGANIZES LIKE GUIDANCE SHOWS, THEN MARINE
CONDITIONS WILL BECOME HAZARDOUS TO SMALL CRAFT. THE FORECAST TAKES A
MIDDLE GROUND, INTRODUCING A HEADLINE FOR CHOPPY SEAS AND DIFFICULT
TRAVEL BETWEEN ISLANDS. THE MAIN CONCERN FOR YAP IS INTERACTION FROM
THE WEAK TROPICAL DISTURBANCE NORTH OF CHUUK IN A FEW DAYS AND THE
CURRENT INVEST 92W THAT IS JUST NORTHWEST OF OUR AREA OF
RESPONSIBILITY IN THE PHILLIPINE SEA. INVEST 92W WILL ASSIST IN THE
DEVELOPMENT OF A WEST SWELL THAT LOOKS TO BECOME ELEVATED ON MONDAY.
BY MONDAY NIGHT, WE START TO SEE INFLUENCE FROM OUR EASTERN
DISTURBANCE AND THE MONSOON PATTERN AS A WHOLE. THIS WOULD ALLOW FOR
SURF TO REACH HAZARDOUS CONDITIONS ALONG WEST FACING REEFS OF YAP.
THE FORECAST INCLUDES A HEADLINE FOR ELEVATED SURF BEGINNING MONDAY
FOR YAP.
GUM WATCHES/WARNINGS/ADVISORIES
GU...NONE.
MP...NONE.
MARIANAS WATERS...NONE.
UPDATE: KLEESCHULTE
MARIANAS/EAST AND WEST MICRONESIA/TROPICAL UPDATE: WHISNANT
MARIANAS: KLEESCHULTE
EAST MICRONESIA/TROPICAL SYSTEMS: MESA
WEST MICRONESIA: WILLIAMS
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