763
FXPQ50 PGUM 062102
AFDGUM
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TIYAN GU
702 AM CHST WED OCT 7 2026
MARIANAS UPDATE
MOSTLY CLOUDY SKIES COVER THE MARIANAS THIS MORNING, WITH NUMEROUS
SHOWERS FILLING IN OVER GUAM AND SOON ROTA, AND SCATTERED SHOWERS
OVER TINIAN AND SAIPAN. BASED ON POP'S, NUMEROUS LOOKED GOOD, IT
SEEMS THAT QPF IS GOING TO BE LACKLUSTER, NOTHING TO WRITE HOME
ABOUT. THAT'S GOOD IN THAT IT WILL MINIMIZE ANY FLOODING POTENTIAL.
SHOWERS WILL DIMINISH AFTER TONIGHT, THEN NEXT WEEK THEY COULD SHRINK
TO ISOLATED. AFTER TONIGHT, WE MIGHT EVEN BE ABLE TO COMBINED THE
ZONES AGAIN. MOST OF THIS WAS IN GOOD AGREEMENT WITH THE INHERITED
FORECAST, SO NO CHANGES WERE NEEDED.
TROPICAL SYSTEMS
TROPICAL STORM KOGUMA IS CENTERED NEAR 14.7N AND 164.5E. IT IS MOVING
TOWARD THE WEST-NORTHWEST AT 15 MPH. THIS GENERAL MOTION IS EXPECTED
TO CONTINUE THROUGH THURSDAY WITH A SLIGHT DECREASE IN FORWARD SPEED.
MAXIMUM SUSTAINED WINDS ARE 60 MPH. KOGUMA IS FORECAST TO INTENSIFY,
AND COULD BECOME A TYPHOON THURSDAY. IT'S GENERAL FORECAST TRACK HAS
IT PASSING EAST THEN NORTH OF THE MARIANAS, AND SOUTH THEN WEST OF
BOTH WAKE ISLAND AND MINAMI TORISHIMA, OUT IN THE OPEN OCEAN. FOR
MORE INFORMATION ON TROPICAL STORM KOGUMA, SEE THE TROPICAL CYCLONE
PUBLIC ADVISORY ISSUED BY THE NATIONAL WEATHER SERVICE UNDER WMO
HEADER WTPQ33 PGUM AND THE TROPICAL CYCLONE WARNING ISSUED BY THE
JOINT TYPHOON WARNING CENTER UNDER WMO HEADER WTPN33 PGTW.
EASTERN MICRONESIA UPDATE
TROPICAL STORM KOGUMA IS IN THE NORTHERN MARSHALL ISLANDS, AWAY FROM
ALL THE EASTERN MICRONESIA MARINE ZONES. THIS LEAVES THE MONSOON
TROUGH AS THE MAIN WEATHER INFLUENCER IN THE REGION. CONVECTION HAS
REALLY DIMINISHED OVER THE ENTIRE REGION, LEAVING MOSTLY DEBRIS
CLOUDS IN ITS WAKE. POHNPEI WILL BE FAIRLY CLOUDY, AT LEAST FOR THIS
MORNING, SO CHANGED THE WORDING FROM MOSTLY SUNNY TO PARTLY CLOUDY.
SHOWERS FOR POHNPEI THOUGH WILL BE ISOLATED THROUGH THE WEEKEND.
SHOWERS FOR KOSRAE WILL ALSO BE ISOLATED THROUGH THE WEEKEND. SHOWERS
AT MAJURO WILL BE ISOLATED TODAY, BUT COULD INCREASE TO SCATTERED
TONIGHT AND STAY THERE THROUGH THE WEEKEND. MARINE CONDITIONS WILL BE
BENIGN THROUGHOUT EASTERN MICRONESIA.
WESTERN MICRONESIA UPDATE
THE MONSOON TROUGH IS ONLY A BIT NORTH OF YAP AND PALAU. THIS IS
GIVING PALAU SCATTERED SHOWERS THROUGH SATURDAY, THEN THEY COULD
DIMINISH TO ISOLATED FOR SUNDAY. YAP WILL HAVE WIDESPREAD SHOWERS
THROUGH TONIGHT, THEN SCATTERED THROUGH AT LEAST SUNDAY. MEANWHILE,
CHUUK IS FAR SOUTH OF THE TROUGH, SO IT SHOULD HAVE ISOLATED SHOWERS
THROUGH THE ENTIRE FORECAST PERIOD, FROM TODAY THROUGH SUNDAY.
OCCASIONAL GUSTS TO 25 KNOTS COULD MAKE MARINE CONDITIONS CHALLENGING
AT PALAU TODAY, OTHERWISE THEY SHOULD BE BENIGN THROUGHOUT WESTERN
MICRONESIA.
PREV DISCUSSION
/ISSUED 529 PM CHST TUE OCT 6 2026/
MARIANAS SYNOPSIS...
SATELLITE IMAGERY AND DOPPLER RADAR INDICATE SCATTERED SHOWERS
ACROSS THE MARIANAS COASTAL WATERS. COMBINED SEAS ARE 5 TO 7 FT.
DISCUSSION...
AN AREA OF SURFACE CONVERGENCE EMBEDDED WITHIN THE MONSOON TROUGH AND
A TRAILING SURFACE TROUGH FROM THE NORTH WILL BRING WETTER WEATHER
OVER THE MARIANAS, PARTICULARLY OVER GUAM AND ROTA. SCATTERED
SHOWERS AND ISOLATED THUNDERSTORMS ARE EXPECTED THIS EVENING,
INCREASING TO NUMEROUS SHOWERS FOR GUAM AND ROTA AFTER MIDNIGHT AND
CONTINUING THROUGH WEDNESDAY NIGHT. LOCALLY HEAVY SHOWERS ARE
POSSIBLE DURING THIS TIME PERIOD, ALTHOUGH, FLASH FLOOD CONCERNS ARE
TOO LOW FOR ANY HYDROLOGY PRODUCTS AT THIS TIME. SO, OPTED FOR A
HEADLINE FOR GUAM AND ROTA TO INDICATE THE POSSIBILITY FOR LOCALLY
HEAVY RAINFALL AND STRONGER GUSTS WITHIN THOSE SHOWERS. THEN, THE
MONSOON TROUGH WILL REMAIN ACTIVE NEAR GUAM AND ROTA THROUGH THE REST
OF THE WEEK, WHEREAS SAIPAN AND TINIAN WILL SEE A REDUCTION IN WINDS
AND SHOWER COVERAGE SHORTLY AFTER MIDWEEK. LOOKING TOWARDS THE END
OF THE WEEK, MODELS INDICATE A TROPICAL DISTURBANCE POTENTIALLY
FORMING OVER THE REGION OR TO THE WEST. DUE TO DISAGREEMENTS BETWEEN
MODEL SOLUTIONS AND A LACK OF ANY NOTABLE CIRCULATIONS ON SATELLITE,
UNCERTAINTY IS HIGH REGARDING THIS PATTERN, SO THE WEEKEND FORECAST
TOPS OUT AT 30 AND 40 PERCENT BETWEEN THE TWO ZONES. FINALLY, BENIGN
CONDITIONS ARE POSSIBLE NEXT WEEK DURING THE HOLIDAY.
MARINE...
THE ONLY ALTIMETRY PASS INDICATES COMBINED SEAS OF 6 TO 8 FT FAR TO
THE WEST, SO COMBINED SEAS ARE FORECAST TO BE 5 TO 7 OVER THE REGION
AND STEADILY DECREASING AS THE NORTHERLY SWELL SUBSIDES. THEN, A
LONG-PERIOD NORTHEASTERLY SWELL WILL APPROACH THE REGION AFTER
MIDWEEK, INCREASING COMBINED SEAS BY A FOOT OR TWO OVER THE WEEKEND.
SURF WILL BE ELEVATED ALONG NORTH FACING REEFS TONIGHT BEFORE QUICKLY
DECREASING A FEW FEET AS THE NORTHERLY SWELL RETREATS. ONCE THE
LONG-PERIOD NORTHEASTERLY SWELLS REACHES THE REGION AFTER MIDWEEK,
HOWEVER, SURF AND RIP CURRENT RISKS MAY BECOME HAZARDOUS FOR NORTH
AND EAST FACING REEFS. THIS SITUATION WILL CONTINUE TO BE MONITORED,
SO THOSE WITH MARINE INTERESTS SHOULD STAY UP TO DATE WITH THE
FORECAST.
TROPICAL SYSTEMS...
AT 100 PM, TROPICAL STORM KOGUMA (27W) WAS CENTERED 315 MILES NORTH-
NORTHWEST OF KWAJALEIN NEAR 13N167E, MOVING NORTHWEST AT 10 MPH.
MAXIMUM SUSTAINED WINDS WERE 50 MPH. TS KOGUMA IS EXPECTED TO MAKE A
SLOW TURN TOWARD THE WEST-NORTHWEST OVER THE NEXT COUPLE OF DAYS AS
IT SLOWLY STRENGTHENS, POSSIBLY BECOMING A TYPHOON WEDNESDAY NIGHT
OR THURSDAY. KOGUMA IS NOT EXPECTED TO DIRECTLY IMPACT THE MARIANAS
OR MICRONESIA.
FOR MORE INFORMATION ON TS KOGUMA, SEE BULLETINS ISSUED BY THE JOINT
TYPHOON WARNING CENTER UNDER WMO HEADER WTPN33 PGTW AND FROM THE
NATIONAL WEATHER SERVICE UNDER WMO HEADER WTPQ33 PGUM.
EASTERN MICRONESIA...
WEAK CONVERGENCE TO THE SOUTH OF THE MONSOON TROUGH WILL CONTINUE TO
WEAKEN THROUGH THE AFTERNOON AND EVENING, WITH SCATTERED SHOWERS AND
ISOLATED THUNDERSTORMS OVER POHNPEI AND KOSRAE BECOMING ISOLATED
SHOWERS NEAR MIDNIGHT. AFTERWARDS, POHNPEI AND KOSRAE LOOK TO REMAIN
DRY THROUGH THE WEEKEND AS THE MONSOON TROUGH PULLS A LITTLE FARTHER
NORTH WITH TS KOGUMA. FOR MAJURO, A DRIER REGIME IS CURRENTLY IN
PLACE AND LOOKS TO CONTINUE THROUGH THURSDAY NIGHT, WITH INCREASED
SHOWERS AND THUNDERSTORMS BY THE END OF THE WEEK AS THE MONSOON
TROUGH REORIENTS FARTHER SOUTH FROM KOGUMA.
FOR THE MARINE FORECAST, NOT MUCH HAS CHANGED. WINDS HAVE SUBSIDED,
AS EXPECTED, AT MAJURO, ALLOWING THE SMALL CRAFT ADVISORY (SCA) TO
EXPIRE. SEAS AND WINDS WILL REMAIN BELOW SCA LEVELS THROUGH THE
REMAINDER OF THE WEEK AND THROUGH THE WEEKEND. SEAS LOOK TO DROP TO
AROUND 3 TO 4 FEET FOR ALL LOCATIONS FOR THE WEEKEND.
WESTERN MICRONESIA...
THE MONSOON SURGE REMAINS THE DOMINANT FEATURE IN THE REGION. THIS
FEATURE IS CURRENTLY LOCATED OVER PALAU AND YAP, AND PRODUCING
SCATTERED TO WIDESPREAD SHOWERS WITH ISOLATED THUNDERSTORMS, AND 10
TO 15 MPH (10 TO 15 KT) WITH OCCASIONAL GUSTS UP TO 30 MPH (25 KT)
WEDNESDAY AT PALAU. QPF MODEL GUIDANCE SUGGESTS ABOUT UP TO AN INCH
OF RAIN PER DAY IS POSSIBLE FOR BOTH ISLANDS. OVERALL, A WET WEEK IS
TO BE EXPECTED WITH CALMER WINDS.
FURTHER TO THE EAST, CHUUK CAN EXPECT A QUITE BENIGN WEATHER PATTERN
THROUGH THE WEEK AS A RIDGE OF HIGH PRESSURE HAS SET UP OVER THE
REGION.
ALTIMETRY SHOWS COMBINED SEAS OF 5 TO 7 FEET ACROSS THE REGION, WITH
THE HIGHEST TO THE EAST OF YAP. WINDS ARE EXPECTED TO BE GENTLE TO
MODERATE WITH GUSTS TO STRONG FOR PALAU AND YAP, WHILE WINDS NEAR
CHUUK IS EXPECTED TO BE LIGHT TO GENTLE. OVERALL, NEAR THE MONSOON
SURGE SEAS ARE EXPECTED TO BE ELEVATED AND CHOPPY, THEN BECOMING
MORE BENIGN TO THE EAST. SEAS NEAR PALAU AND YAP ARE EXPECTED TO
GRADUALLY TAPER DOWN BY A FOOT BY THE BEGINNING OF NEXT WEEK. SEAS
NEAR CHUUK ARE EXPECTED TO REMAIN STEADY THROUGH THE WEEKEND.
GUM WATCHES/WARNINGS/ADVISORIES
GU...NONE.
MP...NONE.
MARIANAS WATERS...NONE.
MARIANAS/EAST AND WEST MICRONESIA/TROPICAL UPDATE: STANKO
MARIANAS: MESA
EAST MICRONESIA/TROPICAL SYSTEMS: KLEESCHULTE
WEST MICRONESIA: BOWSHER
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