832
FXPQ50 PGUM 140949
AFDGUM
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TIYAN GU
749 PM CHST THU MAY 14 2026
MARIANAS SYNOPSIS
A CONVECTIVELY ACTIVE LINE OF SHOWERS IS PRODUCING LOCALLY HEAVY
RAINFALL AND ISOLATED THUNDERSTORMS FOR ROTA AND GUAM TONIGHT. A DRY
TRADE-WIND REGIME WILL MOVE INTO THE MARIANAS THROUGH THE WEEKEND.
COMBINED SEAS AND SURF ESPECIALLY ALONG EAST-FACING REEFS WILL
QUICKLY BUILD OVER THE WEEKEND AS THE TRADE SWELL INCREASES.
DISCUSSION
SATELLITE IMAGERY DEPICTS ISOLATED THUNDERSTORMS AND LOCALLY HEAVY
SHOWERS IN A NORTH-TO-SOUTH ORIENTED AXIS ALONG THE MARIANAS. THE
CONVECTIVE ACTIVITY BEGAN IN THE FAR NORTHERN MARIANAS THIS MORNING
AND HAS BACKFILLED SOUTHWARD ALONG A TRAIN OF SHOWERS AS THE DAY
PROGRESSED. A SUBTROPICAL RIDGE HAS SET UP TO THE NORTHEAST,
ADVECTING DRIER AIR WHICH WILL PUSH OFF THE CONVECTION TO THE WEST
OVER THE WESTERN AND SOUTHERN COASTAL WATERS OF TINIAN AND SAIPAN IN
THE EARLY EVENING. AS FOR ROTA AND GUAM, THE CONVECTIVE ACTIVITY IS
NOT EXPECTED TO SUBSIDE UNTIL AFTER MIDNIGHT WHEN THE DRIER AIR
COMPLETELY ENVELOPS THE REGION, BRINGING PARTLY CLOUDY SKIES AND
ISOLATED SHOWERS FOR THE MARIANAS EARLY FRIDAY MORNING THROUGH FRIDAY
NIGHT. THE TRADES ARE EXPECTED TO INCREASE AS THE RIDGE CONTINUES TO
INTENSIFY, SO BREEZY WINDS AND SCATTERED SHOWERS ARE A POSSIBILITY
AROUND EARLY NEXT WEEK.
MARINE
BUOY AND ALTIMETRY DATA SHOWS COMBINED SEAS OF 3 TO 5 FEET WHICH
WILL REMAIN IN THE FORECAST UNTIL THE TRADE SWELL QUICKLY BUILDS IN
STARTING LATE SATURDAY AFTERNOON, POSSIBLY PEAKING TO 6 TO 8 FEET
EARLY NEXT WEEK. THERE IS A MODERATE RISK OF RIP CURRENTS ALONG
NORTH- AND EAST-FACING REEFS THROUGH THE REST OF THE WEEK. ALONG
WITH THE BUILDING SWELL, SURF MAY INCREASE ALONG EAST-FACING REEFS
THAT MAY WARRANT A HIGH RISK OF RIP CURRENTS, BUT MAY NOT EXCEED
HAZARDOUS CRITERIA. WE WILL CONTINUE TO MONITOR THE SEA STATE ONCE
THE WEEKEND NEARS.
EASTERN MICRONESIA
AFTER A SHORT BURST OF CONVECTIVE ACTIVITY OVERNIGHT NEAR POHNPEI AND
MAJURO, A FAIRLY MODERATE TRADE-WIND REGIME IS EXPECTED TO RETURN TO
THE REGION, BRINGING ON-AND-OFF SHOWERS AND SOME THUNDERSTORMS FOR
THE REST OF THE FORECAST PERIOD. THE LIKELIHOOD OF ANY SIGNIFICANT
TROPICAL DEVELOPMENT CONTINUES TO DECREASE AS MOST OF THE CONVECTION
IS EXPECTED TO SIT EITHER ALONG 10N, OR ALONG THE EQUATOR OVER AT
LEAST THE NEXT SEVERAL DAYS.
COMBINED SEAS OF 4 TO 6 FEET IN POHNPEI AND KOSRAE WATERS, AND 5 TO
7 FEET IN MAJURO WATERS, ARE EXPECTED TO INCREASE ANOTHER FOOT OR TWO
BY THE WEEKEND AS TRADE SWELL AND LOCALIZED WIND WAVES STRENGTHEN.
THIS WILL ALLOW SOME OF THE SEAS TO INTRUDE INTO THE AFOREMENTIONED
WATERS, BUT SEA CONDITIONS WILL REMAIN BELOW LEVELS HAZARDOUS TO
SMALL CRAFT FOR THE TIME BEING.
WESTERN MICRONESIA
A WEAKENING RIDGE ACROSS FAR WESTERN MICRONESIA IS MAINTAINING LIGHT
WINDS ACROSS YAP AND PALAU, WITH ONLY PATCHY SHOWERS SEEN ACROSS THE
AREA. ISLAND-EFFECT SHOWERS ARE STILL POSSIBLE FOR PALAU FRIDAY
AFTERNOON, BEFORE WINDS INCREASE TO LIGHT TO MODERATE ACROSS YAP AND
PALAU THROUGH THE WEEKEND. FARTHER EAST, SCATTERED SHOWERS ARE
BEGINNING TO BUILD INTO CHUUK ALONG AN AREA OF WEAK TRADE-WIND
CONVERGENCE. LATEST MODEL GUIDANCE IS LESS KEEN ON AN WEAK TROPICAL
DISTURBANCE DEVELOPING, HOWEVER, A BAND OF TRADE-WIND CONVERGENCE OR
AN ITCZ FRAGMENT STILL LOOKS TO DEVELOP ACROSS CHUUK, SOUTHERN YAP
STATE, AND THE FAR SOUTHERN ISLANDS OF PALAU OVER THE NEXT FEW DAYS.
FRESH TO STRONG TRADES NORTH OF THIS FEATURE AND AN EMBEDDED TROUGH,
WILL SUPPORT A MORE UNSETTLED PATTERN ACROSS CHUUK FRIDAY THROUGH AT
LEAST SATURDAY NIGHT, BEFORE THIS FEATURE SHIFTS NORTHWEST. FOR YAP
AND PALAU, A SERIES OF WEAK TRADE-WIND TROUGHS WILL BRING PERIODIC
UPTICKS IN SHOWERS OVER THE NEXT SEVERAL DAYS, THEN THE SHIFT IN THE
DEVELOPING PATTERN NEAR CHUUK MAY ALSO RESULT IN A BROADER AREA OF
SCATTERED SHOWERS BUILDING INTO YAP EARLY NEXT WEEK.
OVERALL, BENIGN MARINE CONDITIONS ARE EXPECTED OVER THE NEXT SEVERAL
DAYS. ALTIMETRY DATA SHOWS COMBINED SEAS OF 3 TO 5 FEET ACROSS THE
REGION. A BUILDING TRADE SWELL IS EXPECTED TO INCREASE SEAS TO 4 TO
6 FEET AT CHUUK STARTING FRIDAY AND AT YAP AROUND SUNDAY AND MONDAY.
FOR PALAU, SEAS LOOK TO REMAIN AROUND 2 TO 4 FEET THROUGH MUCH OF THE
UPCOMING WEEK.
GUM WATCHES/WARNINGS/ADVISORIES
GU...NONE.
MP...NONE.
MARIANAS WATERS...NONE.
MARIANAS: MESA
EAST MICRONESIA: MONTVILA
WEST MICRONESIA: CRUZ
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