388
FXPQ50 PGUM 041936
AFDGUM
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TIYAN GU
536 AM CHST WED AUG 5 2026
MARIANAS UPDATE
A LEADING EDGE OF A SURFACE TROUGH EXTENDING FROM DISTANT TYPHOON
DOLPHIN (12W) CONTINUES TO BRING SCATTERED SHOWERS AND ISOLATED
THUNDERSTORMS TO THE REGION, CARRIED BY A MODERATE TO STRONG WESTERLY
MONSOON SURGE. LATEST SURFACE OBSERVATIONS, RADAR AND SATELLITE
ANALYSIS INDICATED THAT SUSTAINED WINDS HAVE FALLEN BELOW 30 MPH. AS
SUCH, WINDY CONDITIONS ARE NO LONGER EXPECTED, SO THE WIND ADVISORY
WAS CANCELLED EARLIER IN THE NIGHT. OTHERWISE, A SMALL CRAFT
ADVISORY, HIGH SURF ADVISORY AND HIGH RIP CURRENT RISK STATEMENT
REMAIN IN EFFECT FOR THE MARIANAS.
EASTERN MICRONESIA UPDATE
A TROPICAL RIDGE EXTENDING EAST FROM A BUFFER CIRCULATION OVER
KAPINGAMARANGI, WILL CONTINUE TO PRODUCE A DRY SPELL ACROSS THE
REGION FOR MUCH OF THE FORECAST PERIOD. AS SUCH, THE FORECAST REMAINS
UNCHANGED. CONTINUE TO EXPECT AN EXTENSIVE PERIOD OF WESTERLY SWELLS
AS THE MONSOON TROUGH REMAINS ANCHORED WELL NORTH OF POHNPEI, KOSRAE
AND MAJURO.
WESTERN MICRONESIA UPDATE
SIMILAR TO EASTERN MICRONESIA, A TROPICAL RIDGE EXTENDING WEST FROM
THE AFOREMENTIONED BUFFER CIRCULATION OVER KAPINGAMARANGI IN POHNPEI
STATE, WILL CONTINUE TO BRING A DRIER REGIME ACROSS THE REGION AS
MOST OF THE SHOWERS REMAIN NORTH OF THE MAIN ISLANDS. AS SUCH, THE
FORECAST REMAINS UNCHANGED. EXPECT SURF TO CONTINUE BUILDING ALONG
NORTH FACING REEFS OF PALAU AND YAP OVER THE COMING DAYS, AS DISTANT
TYPHOON DOLPHIN CONTINUES TO HEAD FOR OKINAWA WHILE PRODUCING PULSES
OF NORTHERLY SWELL ACROSS THE WESTERN PACIFIC.
PREV DISCUSSION
/ISSUED 533 PM CHST TUE AUG 4 2026/
MARIANAS SYNOPSIS...
SATELLITE AND RADAR OBSERVATIONS SHOW SCATTERED TO NUMEROUS SHOWERS
AND ISOLATED THUNDERSTORMS. SUSTAINED WINDS HAVE BEEN OBSERVED AT 25
TO 35 MPH WITH GUSTS TO 45 MPH TODAY. ALTIMETRY AND BUOY DATA SHOW
COMBINED SEAS BETWEEN 8 TO 11 FEET.
DISCUSSION...
THE MONSOON SURGE THAT HAS BROUGHT STRONG TO NEAR GALE WINDS TO THE
MARIANAS OVER THE LAST COUPLE OF DAYS WILL PERSIST TONIGHT BEFORE
BEGINNING A WEAKENING TREND OVER THE NEXT COUPLE OF DAYS. ALTHOUGH
WINDS LOOK TO DECREASE TOWARDS THE MIDDLE OF THE WEEK, THE MONSOON
LOOKS TO REMAIN OVER THE MARIANAS, KEEPING SHOWERS CHANCES MEDIUM TO
HIGH-END SCATTERED (40-50%). THE WIND ADVISORY REMAINS IN EFFECT
UNTIL 6 AM WEDNESDAY. 20 TO 30 MPH WINDS WITH GUSTS TO 40 MPH WILL
CONTINUE TO BE POSSIBLE, ESPECIALLY IN AND AROUND HEAVIER SHOWERS.
WINDS LOOK TO DECREASE TO 10 TO 15 MPH BY WEDNESDAY NIGHT AS A SHORT
LULL IN HIGHER WINDS MOVES OVER THE REGION.
TOWARDS THE LATTER HALF OF THE WEEK, INTO THIS WEEKEND, AND INTO
NEXT WEEK, THE FORECAST IS DEPENDENT ON THE LOCATION AND STRENGTH OF
NEWLY DESIGNATED INVEST 96W LOCATED SOUTH OF WAKE ISLAND. INVEST 96W
IS CURRENTLY WEAK WITH AN ELONGATED CIRCULATION, SEE THE TROPICAL
DISCUSSION FOR MORE DETAILS. THE WESTERLY WINDS FEEDING INTO INVEST
96W WILL INTENSIFY AS THE PRESSURE GRADIENT GROWS STRONGER. THIS
WILL ALLOW THE MONSOON TO RE-STRENGTHEN OVER THE MARIANAS LEADING TO
A SECONDARY SURGE. UNCERTAINTY REMAINS HIGH ON THE PLACEMENT OF THE
MONSOON SURGE. THE GFS TREATS 96W MORE LIKE A FULLY TROPICAL SYSTEM
EARLY NEXT WEEK, LEADING TO STRONGER WINDS CLOSER TO THE CIRCULATION
AND NORTH OF THE CNMI. MEANWHILE, THE ECMWF HAS MORE OF A
SUBTROPICAL APPEARANCE WITH THE STRONG WINDS WELL SOUTH OF THE
CIRCULATION, OVER THE MARIANAS. THE IMPACTS WOULD DIFFER GREATLY
WITH THE POTENTIAL FOR HEAVY RAINFALL AND NEAR GALE WINDS NEAR THE
CENTER OF THE MONSOON SURGE. A HYDROLOGICAL PRODUCT MAY BE NEEDED IN
THE COMING DAYS IF CONFIDENCE INCREASES IN THE SOUTHERN SOLUTION.
THOSE IN THE MARIANAS SHOULD CONTINUE TO MONITOR FORECASTS FOR
UPDATES IN THE PROGRESSION OF THE MONSOON.
MARINE...
FRESH TO STRONG WESTERLIES WITH OCCASIONAL GALE FORCE GUSTS
WILL CONTINUE THROUGH EARLY WEDNESDAY MORNING ACROSS THE MARIANAS,
ESPECIALLY NEAR HEAVIER SHOWERS. THE MONSOON LOOKS TO BRIEFLY WEAKEN
OVER THE NEXT COUPLE OF DAYS, BEFORE REINVIGORATING LATER THIS WEEK.
A DISTANT SWELL FROM TYPHOON DOLPHIN (12W) CONTINUES TO MAKE ITS WAY
INTO THE REGION AND WILL BEGIN TO SHIFT FROM THE NORTH TO THE
NORTHWEST. MEANWHILE, A STRENGTHENING WEST TO SOUTHWEST SWELL WILL
CONTINUE TO IMPACT OUR REGION OVER THE NEXT WEEK. THIS COMBINATION
IN SWELLS AND WIND WAVES WILL KEEP SEAS AROUND 10 FEET ACROSS THE
COASTAL WATERS, MAINTAINING HAZARDOUS SEA CONDITIONS FOR MUCH OF THE
WEEK. A SMALL CRAFT ADVISORY REMAINS IN EFFECT THROUGH EARLY FRIDAY
MORNING.
A HIGH SURF ADVISORY IS IN EFFECT FOR WEST AND NORTH FACING REEFS,
AND A HIGH RISK OF RIP CURRENTS IS IN EFFECT FOR WEST, NORTH, AND
EAST FACING REEFS OF THE MARIANAS. AS MONSOONAL SWELLS STRENGTHEN
AND PERIOD INCREASES, SURF COULD APPROACH 12 FEET ACROSS NORTH
FACING REEFS WEDNESDAY NIGHT. A MODERATE RISK OF LIGHTNING IS
EXPECTED THROUGH THE WEEK.
TROPICAL SYSTEMS...
A WEAK CIRCULATION, JOINT TYPHOON WARNING CENTER'S (JTWC) INVEST 96W
IS CENTERED SOUTH-SOUTHEAST OF WAKE ISLAND NEAR 16N164E. INVEST 96W
IS CURRENTLY RATED SUB-LOW, MEANING DEVELOPMENT IS POSSIBLE, BUT NOT
EXPECTED OVER THE NEXT FEW DAYS. 96W IS EXPECTED TO SLOWLY MOVE WNW
OVER THE NEXT FEW DAYS, WITH MODEL GUIDANCE SHOWING LITTLE, IF ANY,
DEVELOPMENT AS IT PROGRESSES. INVEST 96W WILL BE MONITORED CLOSELY
OVER THE NEXT FEW DAYS, BUT IT CURRENTLY DOES NOT APPEAR TO BE A
THREAT TO THE MARIANAS OR MICRONESIA.
EASTERN MICRONESIA...
AN ABNORMALLY DRY REGIME HAS SET UP OVER EASTERN MICRONESIA, WITH
LITTLE TO NO CONVECTION EXPECTED OVER THE NEXT SEVERAL DAYS. KOSRAE
LOOKS TO BE THE DRIEST POINT, WITH SEVERAL DAYS, INCLUDING THE
WEEKEND, WITH POPS (PROBABILITY OF PRECIPITATION) LESS THAN 10
PERCENT TO NEAR ZERO. POHNPEI AND MAJURO DON'T LOOK TO FAIR MUCH
BETTER, WITH POPS REMAINING AT OR BELOW 20 PERCENT THROUGH THE
WEEKEND.
FOR THE MARINE FORECAST, EXPECT GENTLE TO MODERATE WINDS AT POHNPEI
TO BECOME LIGHT TO GENTLE THURSDAY AND CONTINUE THROUGH THE WEEKEND.
FOR KOSRAE AND MAJURO, LIGHT TO GENTLE WINDS WILL PREVAIL THROUGH THE
WEEKEND. COMBINED SEAS LOOK TO REMAIN FAIRLY STABLE THROUGH THE
WEEKEND AS WELL.
WESTERN MICRONESIA...
A MONSOON PATTERN REMAINS NORTH OF THE REGION, SHIFTING SLIGHTLY
NORTH AWAY FROM YAP THIS AFTERNOON. A TRAILING LINE OF SHOWERS
REMAINS STRETCHED OUT ACROSS EASTERN YAP STATE, OTHERWISE RELATIVELY
QUIET WEATHER PERSISTS FOR MUCH OF THE REGION THIS WEEK. THEN, A
SOUTHERN BEND IN THE MONSOON TROUGH BRINGS A RETURN TO SCATTERED
SHOWERS AT CHUUK LATE WEEK.
COMBINED SEAS HAVE INCREASED TO 5 TO 7 FEET, WITH SEAS UP TO 8 FEET
AT CHUUK. GENTLE TO FRESH SOUTHWESTERLIES ARE EXPECTED TO CONTINUE AT
PALAU, WITH MODERATE TO FRESH ACROSS YAP AND CHUUK. AS TY DOLPHIN
PASSES TO THE DISTANT NORTH, NORTH TO NORTHEAST SWELL CONTINUES TO
BUILD ACROSS YAP AND PALAU, SHIFTING MORE NORTHERLY IN THE COMING
DAYS. ELEVATED SURF IS EXPECTED THIS WEEK ALONG NORTH-FACING REEFS,
POTENTIALLY BECOMING HAZARDOUS STARTING WEDNESDAY NIGHT. SIMILARLY,
AN INCREASE IN SURF ALONG WEST-FACING REEFS IS EXPECTED AS WEST TO
SOUTHWEST MONSOON SWELL BUILDS. THESE TRENDS IN SWELL AND ELEVATED
WIND WAVES COULD SEE CONDITIONS APPROACH HAZARDOUS LEVELS FOR SMALL
CRAFT IN THE LATTER HALF OF THE WEEK FOR YAP.
GUM WATCHES/WARNINGS/ADVISORIES
GU...HIGH RIP CURRENT RISK THROUGH SATURDAY AFTERNOON FOR GUZ001.
HIGH SURF ADVISORY UNTIL 4 PM CHST SATURDAY FOR GUZ001.
WIND ADVISORY UNTIL 6 AM CHST EARLY THIS MORNING FOR GUZ001.
MP...HIGH RIP CURRENT RISK THROUGH SATURDAY AFTERNOON FOR MPZ001>003.
HIGH SURF ADVISORY UNTIL 4 PM CHST SATURDAY FOR MPZ001>003.
WIND ADVISORY UNTIL 6 AM CHST EARLY THIS MORNING FOR MPZ001>003.
MARIANAS WATERS...SMALL CRAFT ADVISORY UNTIL 6 AM CHST FRIDAY FOR PMZ151>154.
MARIANAS/EAST AND WEST MICRONESIA/TROPICAL UPDATE: MONTVILA
MARIANAS: WILLIAMS
EAST MICRONESIA/TROPICAL: KLEESCHULTE
WEST MICRONESIA: CRUZ
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