898
FXPQ50 PGUM 061920
AFDGUM
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TIYAN GU
520 AM CHST SUN SEP 7 2025
MARIANAS UPDATE
LITTLE CHANGE IN FORECAST PHILOSOPHY, JUST ADDED THUNDERSTORMS IN
FOR TODAY BASED ON THE FACT THAT WE'VE HAD SOME EARLY THIS MORNING.
THERE ARE ALSO SOME MORE COLD CLOUD TOPS AND LIGHTNING STRIKES TO OUR
EAST, SO IT'S NOT CLEAR WHY WE WOULD PROJECT THEM TO END AT THIS
TIME.
EASTERN MICRONESIA UPDATE
ALSO LITTLE CHANGE IN FORECAST PHILOSOPHY HERE, JUST INCREASED THE
CLOUDS AT MAJURO AND KOSRAE. MAJURO IS JUST BARELY NORTH OF THE
EAST-WEST ORIENTED RIBBON OF CONVECTION, AND KOSRAE IS JUST SOUTH.
FOR NOW POHNPEI IS JUST WEST, LOOKS LIKE THAT WILL HOLD TODAY.
HOWEVER, POSSIBLY MAJURO AND MOST LIKELY KOSRAE COULD HAVE SCATTERED
SHOWERS MOVING IN THIS AFTERNOON. CURRENT PACKAGE HAS THEM MOVING IN
TONIGHT THOUGH, SO FOR NOW FIGURED THAT IS GOOD. EVERYONE IS
EXPECTING INCREASED SHOWERS LATER, OR AT LEAST SHOULD BE.
WESTERN MICRONESIA UPDATE
AGAIN, LITTLE CHANGE IN FORECAST PHILOSOPHY, JUST UPPED THE CLOUDS A
BIT AT YAP, WHICH WOULD HAVE BEEN MOSTLY SUNNY TODAY. OPTED FOR
PARTLY SUNNY INSTEAD. STUCK WITH ISOLATED SHOWERS BECAUSE WHILE A BIG
MASS OF CONVECTION WAS MOVING IN, TOPS WERE WARMING.
PREV DISCUSSION
/ISSUED 652 PM CHST SAT SEP 6 2025/
MARIANAS SYNOPSIS...
LIGHT TO GENTLE NORTHEASTERLIES PREVAIL ACROSS THE REGION. SATELLITE
IMAGERY AND DOPPLER RADAR INDICATE SLOW-MOVING SHOWERS FORMING IN
CNMI WATERS. THE BUOYS SHOW SEAS ARE AROUND 3 FEET.
DISCUSSION...
A PASSING BROAD SURFACE TROUGH INTERACTING WITH A TROPICAL UPPER
TROPOSPHERIC TROUGH (TUTT) CELL ALOFT, IS LIKELY TO PRODUCE PATCHY
SHOWERS AND SOME THUNDERSTORMS OVERNIGHT ACROSS THE REGION. AFTER, A
PERIOD OF ISOLATED TO LOW-END SCATTERED SHOWERS BROUGHT BY MODERATE
TRADES IS EXPECTED TO LAST FOR MUCH OF NEXT WEEK.
MARINE/SURF...
COMBINED SEAS OF AROUND 4 FEET, WILL BRIEFLY DROP A FOOT EARLY NEXT
WEEK, BEFORE GOING UP A FEW FEET ONCE TRADE AND NORTHERLY SWELLS,
ALONG WITH LOCALIZED WIND WAVES, STRENGTHEN AROUND MIDWEEK. A LOW RISK
OF RIP CURRENTS IS EXPECTED ALONG ALL REEFS OF THE MARIANAS FOR AT
LEAST THE NEXT SEVERAL DAYS. BY MIDWEEK, TRADE AND NORTHERLY SWELLS
ARE EXPECTED TO STRENGTHEN SLIGHTLY, ALLOWING SURF TO INCREASE AND
POTENTIALLY INTRODUCING A MODERATE RISK OF RIP CURRENTS TO NORTH AND
EAST FACING REEFS AS EARLY AS TUESDAY NIGHT.
EASTERN MICRONESIA...
THE DRY TRADE-WIND PATTERN CONTINUES OVER EASTERN MICRONESIA THIS
EVENING, WITH ONLY SPOTTY SHOWERS SEEN ACROSS THE REGION. THIS DRY
PATTERN LOOKS TO CONTINUE THROUGH THE REMAINDER OF THE WEEKEND. IT
STILL LOOKS LIKELY THAT THE INTER-TROPICAL CONVERGENCE ZONE (ITCZ)
WILL MAKE A COMEBACK, THOUGH IT WAS PUSHED BACK A LITTLE LATER THAN
PREVIOUSLY EXPECTED. REGARDLESS, ONCE THE ITCZ REFORMS, THE REGION IS
IN FOR ANOTHER ROUND OF WET CONDITIONS. CONVECTION WILL BEGIN TO
INCREASE MONDAY WITH THE RISK OF THUNDERSTORMS INCREASING LATER IN
THE EVENING. THE ITCZ LOOKS TO PEAK AROUND THE MIDDLE OF NEXT WEEK.
MAINTAINED POPS AT AROUND 50% FOR NOW, THOUGH THIS COULD CHANGE AS
THE LOCATION AND STRENGTH OF THE ITCZ BECOMES MORE CLEAR. THIS WET
PATTERN WILL THEN BEGIN TO SUBSIDE AROUND THE END OF NEXT WEEK.
LITTLE CHANGE IN THE MARINE FORECAST. COMBINED SEAS OF 3 TO 4 FEET
ARE EXPECTED TO CONTINUE THROUGH THE MIDDLE OF NEXT WEEK, THEN BUILD
SLIGHTLY AROUND THE END OF THE WEEK. LIGHT TO GENTLE TRADE WINDS ARE
EXPECTED THROUGH THE COMING WEEK.
WESTERN MICRONESIA...
A BROAD SURFACE TROUGH IS MOVING AWAY FROM CHUUK AND INTO EASTERN
YAP STATE THIS EVENING. THIS FEATURE IS EXPECTED TO CONTINUE
PROPAGATING WESTWARD, INCREASING SHOWERS FOR YAP AND PALAU AROUND
SUNDAY NIGHT THROUGH MONDAY NIGHT. MEANWHILE, SHOWERS ARE EXPECTED TO
TREND DOWN NEAR WENO OVERNIGHT AND SUNDAY. THEN THE ITCZ BEGINS TO
REBUILD IN EASTERN MICRONESIA AND MUCH OF CHUUK STATE NEXT WEEK,
TRENDING TOWARDS WETTER WEATHER BY MONDAY NIGHT. AN ITCZ FRAGMENT
LOOKS TO BRING ANOTHER UPTICK IN SHOWERS FOR YAP AND PALAU AS WELL,
AROUND WEDNESDAY AND THURSDAY.
ALTIMETRY DATA SHOWS BENIGN SEAS OF 2 TO 3 FEET NEAR YAP AND PALAU
AND 3 TO 4 FEET NEAR CHUUK. COMBINED SEAS ARE EXPECTED TO INCREASE TO
3 TO 5 FEET AROUND THE MIDDLE OF NEXT WEEK WHEN A PULSE OF NORTHERLY
SWELL MOVES THROUGH THE REGION.
GUM WATCHES/WARNINGS/ADVISORIES
GU...NONE.
MP...NONE.
MARIANAS WATERS...NONE.
MARIANAS/EAST AND WEST MICRONESIA UPDATE: STANKO
MARIANAS: MONTVILA
EAST MICRONESIA: KLEESCHULTE
WEST MICRONESIA: CRUZ
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