290  
FXPQ50 PGUM 310726  
AFDGUM  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE TIYAN GU  
526 PM CHST SAT MAY 31 2025  
   
MARIANAS SYNOPSIS
 
 
GENTLE TO MODERATE TRADES PREVAIL. SATELLITE IMAGERY AND DOPPLER  
RADAR INDICATE A FEW LINES OF SHOWERS ENTERING GUAM'S NORTHEASTERN  
WATERS. THE BUOYS INDICATE SEAS ARE 4 TO 5 FEET.  
 

 
   
DISCUSSION
 
 
A COMBINATION OF A LINGERING TUTT CELL OVERHEAD, SOUTHEASTERLIES WITH  
INCREASING MOISTURE COLUMNS, AND A BUILDING RIDGE TO THE NORTHWEST,  
ARE ALLOWING ISOLATED TO LOW-END SCATTERED SHOWERS AND SOME  
THUNDERSTORMS TO MOVE IN ACROSS THE MARIANAS FOR MUCH OF THE FIRST  
HALF OF NEXT WEEK. SHOWERS WILL BEGIN TO INCREASE MORESO STARTING  
THURSDAY, AS A CONVERGENCE ZONE BUILDS ACROSS THE REGION INTO NEXT  
WEEKEND.  
 

 
   
MARINE
 
 
LITTLE CHANGE IN THE MARINE FORECAST. COMBINED SEAS OF 4 TO 6 FEET  
WILL TAPER DOWN A FOOT SUNDAY, STAYING AS SUCH THROUGH AT LEAST  
MIDWEEK. A MODERATE RISK OF RIP CURRENTS IS EXPECTED ALONG EAST  
FACING REEFS THROUGH AT LEAST THE FIRST HALF OF NEXT WEEK.  
 

 
   
FIRE WEATHER
 
 
ONLY A TRACE OF RAIN HAS FALLEN AT THE AIRPORT SINCE MIDNIGHT. MORE  
SHOWERS ARE SEEN UPSTREAM AND HEADING FOR GUAM, BUT THEY ARE NOT  
EXPECTED TO BRING A WETTING RAIN TONIGHT. AS SUCH, THE KBDI MAY  
EITHER STAY AROUND THE SAME OR DROP SLIGHTLY, WHICH IS CURRENTLY AT  
720. THERE WILL BE A FEW CHANCES FOR SCATTERED SHOWERS THE NEXT FEW  
DAYS, BUT A WIDESPREAD WETTING RAIN REMAINS UNLIKELY THE NEXT FEW  
DAYS. IN ADDITION, THE ALREADY STRESSED FOLIAGE, ESPECIALLY IN THE  
SOUTHERN PORTIONS OF GUAM, STILL CONTINUE TO POSE A HIGH FIRE DANGER,  
BUT RED FLAG CONDITIONS ARE NOT EXPECTED TO BE MET.  
 

 
   
EASTERN MICRONESIA
 
 
AN INTER-TROPICAL CONVERGENCE ZONE (ITCZ) CONTINUES TO STRENGTHEN  
ACROSS EASTERN MICRONESIA. THE ITCZ STRETCHES WEST, CURRENTLY SOUTH  
OF MAJURO, INTO KOSRAE. THIS FEATURE IS GENERATING SCATTERED SHOWERS  
AND AN OCCASIONAL THUNDERSTORM OVER KOSRAE. THERE IS A TRADE-WIND  
TROUGH THAT IS STILL CROSSING THE DATE LINE THAT LOOKS TO MOVE TOWARD  
MAJURO AS IT PROGRESSES, DRAGGING THE ITCZ A LITTLE FARTHER NORTH.  
THIS WILL BRING INCREASING CONVECTION TO MAJURO BY SUNDAY MORNING.  
FOR POHNPEI, ANOTHER TRADE-WIND TROUGH IS CURRENTLY MOVING THROUGH  
THE STATE, PRODUCING SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS  
THERE THIS AFTERNOON. THESE SHOWERS LOOK TO MOVE OUT THIS AFTERNOON.  
HOWEVER, CONVECTION ALONG THE WESTERN END OF THE ITCZ LOOKS TO MOVE  
INTO POHNPEI DURING THE AFTERNOON HOURS. LATEST MODEL GUIDANCE  
INDICATES THAT AN OVERALL WET, UNSETTLED PATTERN WILL REMAIN OVER THE  
REGION THROUGH THE MIDDLE OF NEXT WEEK AS THE DEVELOPING ITCZ  
REMAINS ACTIVE. THERE WILL BE PERIODS OF INCREASED CONVECTION AS WEAK  
TRADE-WIND TROUGHS TRAVERSE ACROSS THE AREA AND INTERACT WITH THE  
ITCZ. MAJURO SHOULD SEE A DRIER TREND AROUND WEDNESDAY NEXT WEEK AS  
THE ITCZ DRIFTS BACK TO THE SOUTH. THIS DRIER PATTERN ALSO LOOKS TO  
MOVE INTO POHNPEI SATURDAY AS THE ITCZ ALSO RETREATS SOUTH AND  
WEAKENS OVER THE STATE. KOSRAE, HOWEVER, LOOKS TO REMAIN IN A WET  
PATTERN FOR A BIT LONGER AS THE ITCZ REMAINS OVER THE ISLAND AS IT  
WEAKENS AND EVENTUALLY DISSIPATES.  
 
COMBINED SEAS OF 4 TO 6 FEET FOR POHNPEI AND KOSRAE WILL SLOWLY  
SUBSIDE OVER THE NEXT FEW DAYS, DROPPING TO BETWEEN 3 AND 5 FEET  
EARLY NEXT WEEK. FOR MAJURO, SEAS ARE SLIGHTLY HIGHER, CURRENTLY  
BETWEEN 5 AND 7 FEET. SEAS LOOK TO SUBSIDE TO BETWEEN 3 AND 5 FEET  
FOR MAJURO LATER NEXT WEEK. GENTLE TO MODERATE TRADE WINDS WILL  
CONTINUE INTO THE COMING WEEK, POSSIBLY BECOMING LIGHT AROUND MIDWEEK  
AT POHNPEI AND KOSRAE.  
 

 
   
WESTERN MICRONESIA
 
 
SATELLITE IMAGERY THIS AFTERNOON SHOWS SCATTERED SHOWERS OVER AND  
JUST SOUTH OF PALAU, WITHIN AN AREA OF TRADE-WIND CONVERGENCE ALONG  
THE NORTHERN PERIPHERY OF A BROAD SURFACE TROUGH. YAP SITS IN A  
FAIRLY QUIET TRADE REGIME FOR THE TIME BEING, WITH ISOLATED SHOWERS  
AND PARTLY CLOUDY SKIES ACROSS THE AREA. FURTHER SOUTHEAST OVER YAP  
STATE, AN AREA OF WIDESPREAD SHOWERS AND CLOUDINESS IS SEEN,  
ASSOCIATED WITH A BROAD SOUTH-SOUTHWEST TO NORTH-NORTHEAST ORIENTED  
TROUGH CENTERED BETWEEN SOROL AND EAURIPIK. FURTHER EAST, MUCH OF  
CHUUK STATE IS FAIRLY DRY THIS AFTERNOON, WITH JUST ISOLATED SHOWERS  
AND A FEW REMNANT OUTFLOW BOUNDARIES SEEN NEAR CHUUK LAGOON FROM DEEP  
CONVECTION TO THE NORTHEAST. TRADE WINDS ARE MOSTLY GENTLE ACROSS  
YAP STATE AND THE REPUBLIC OF PALAU, AND GENTLE TO MODERATE OVER  
CHUUK. DISORGANIZED TRADE-WIND CONVERGENCE AND THE APPROACH OF A  
BROAD TRADE-WIND TROUGH WILL MAINTAIN SCATTERED SHOWERS NEAR PALAU  
TONIGHT INTO EARLY NEXT WEEK, AND LEAD TO INCREASING SHOWERS FOR YAP  
LATER TONIGHT. ALTHOUGH FAIRLY QUIET FOR NOW, CHUUK AND YAP CAN  
EXPECT PATCHY SHOWERS FROM TIME TO TIME THROUGH EARLY NEXT WEEK, WITH  
AN INCREASE IN SHOWER CHANCES AROUND THE MIDDLE OF NEXT WEEK.  
SEVERAL WEAKER TRADE-WIND TROUGHS LOOK TO CROSS THE AREA OVER THE  
NEXT FEW DAYS, BEFORE A MORE ROBUST DISTURBANCE OR TWO LOOK TO BUILD  
OVER CHUUK AND EASTERN YAP STATE AROUND WEDNESDAY.  
 
BENIGN MARINE CONDITIONS CONTINUE. COMBINED SEAS OF 2 TO 4 FEET NEAR  
PALAU AND YAP ARE EXPECTED TO CONTINUE THROUGH AT LEAST THE FIRST  
HALF OF THIS WEEK. COMBINED SEAS OF 4 TO 6 FEET NEAR CHUUK WILL  
CONTINUE THROUGH THE WEEKEND, STARTING TO TAPER DOWN EARLY NEXT WEEK  
AS THE PRIMARY SWELL WEAKENS.  
 

 
   
GUM WATCHES/WARNINGS/ADVISORIES
 
 
GU...NONE.  
MP...NONE.  
MARIANAS WATERS...NONE.  

 
 

 
 
MARIANAS: MONTVILA  
EAST MICRONESIA: KLEESCHULTE  
WEST MICRONESIA: DECOU  
 
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