713
FXPQ50 PGUM 031918
AFDGUM
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TIYAN GU
518 AM CHST WED MAR 4 2026
MARIANAS UPDATE
MOSTLY DRY WEATHER WILL PERSIST THROUGH THE WORK
WEEK WITH SHOWER AND THUNDERSTORM CHANCES INCREASING THIS WEEKEND AS
MOISTURE ASSOCIATED WITH A POTENTIAL DISTURBANCE SPREADS OVER THE
REGION. PLEASE SEE THE HYDROLOGY SECTION FROM THE PREVIOUS DISCUSSION
BELOW FOR ADDITIONAL DETAILS AND HAZARDS ASSOCIATED WITH THE
RAINFALL EXPECTED THIS WEEKEND. AN INCREASE IN NORTHERLY SWELL LATE
WEEK IS EXPECTED TO BUILD SEAS UP TO 10 FEET, WHICH WOULD WARRANT A
SMALL CRAFT ADVISORY AS EARLY AS FRIDAY NIGHT. GENTLE TO MODERATE
WINDS ARE EXPECTED, INCREASING TO MODERATE TO FRESH LATE WEEK.
ADDITIONALLY, SURF MAY REACH HAZARDOUS LEVELS ALONG NORTH FACING
REEFS LATE THIS WEEK AND THIS WEEKEND.
EASTERN MICRONESIA UPDATE
A SERIES OF TRADE-WIND TROUGHS WILL CONTINUE TO PROMOTE PERIODS OF
ISOLATED TO SCATTERED SHOWERS, ALONG WITH ISOLATED THUNDERSTORMS,
DURING THE NEXT COUPLE OF DAYS. SEAS WILL REMAIN BETWEEN 5 TO 7 FEET
THROUGH THE END OF THE WORK WEEK, WITH WINDS INCREASING TO MODERATE
THE LATTER HALF OF THE WEEK. THOUGH, WINDS AT KOSRAE SHOULD REMAIN
GENTLE WITH AN INCREASE TO MODERATE OVER THE WEEKEND. MINOR COASTAL
INUNDATION IS POSSIBLE DURING TIMES OF HIGH TIDE FOR NORTHERN AND
EASTERN SHORELINES OF MAJURO THROUGH FRIDAY DUE TO ELEVATED SURF AND
THE FULL MOON CYCLE. A NORTHERLY SWELL IS MOVING THROUGH THE REGION
WHICH IS EXPECTED TO BRING ELEVATED SURF LATE WEEK AND THIS WEEKEND
FOR THE NORTH FACING REEFS OF POHNPEI AND KOSRAE. ALTHOUGH NOT
EXPECTED AT THIS TIME, IT REMAINS A POSSIBILITY FOR SURF TO REACH
HAZARDOUS LEVELS.
WESTERN MICRONESIA UPDATE
OVERNIGHT SATELLITE IMAGERY SHOWED IMPROVING CONDITIONS AT CHUUK SO
HAVE DECREASED SHOWER CHANCES FROM NUMEROUS TO SCATTERED FOR TODAY.
THIS WILL BE A BRIEF LULL IN ACTIVITY AND SHOWER CHANCES WILL
INCREASE BACK TO NUMEROUS AS THE DISTURBANCE WITHIN THE NEAR-
EQUATORIAL TROUGH (NET) BECOMES BETTER ORGANIZED. OVERNIGHT SHOWERS
AND THUNDERSTORMS LINGER IN THE VICINITY OF PALAU THIS MORNING, SO
HAVE INCREASED SHOWER CHANCES AND LOCALLY HEAVY RAINFALL WILL BE
POSSIBLE THROUGH THE MORNING HOURS. SHOWER ACTIVITY IS EXPECTED TO
REMAIN ISOLATED AT YAP, SO HAVE DECREASED SHOWERS FROM SCATTERED
TO ISOLATED TONIGHT. LIGHT TO MODERATE WINDS ARE EXPECTED ACROSS THE
REGION, WITH STRONGER GUSTS POSSIBLE WITH THE DEVELOPING DISTURBANCE
ON THURSDAY AND FRIDAY.
PREV DISCUSSION
/ISSUED 648 PM CHST TUE MAR 3 2026/
MARIANAS SYNOPSIS...
SATELLITE IMAGERY SHOWS MOSTLY CLOUDY SKIES AND RADAR IMAGERY SHOWS
ISOLATED SHOWERS OVER THE MARIANAS. ALTIMETRY SHOWS SEAS OF 6 TO 7
FEET TO THE EAST OF THE ISLANDS. IPAN BUOY SHOWS EASTERLY SWELL
NEAR 5.5 FEET AT 10.5 SECONDS.
DISCUSSION...
A DRY PATTERN HAS SET UP OVER THE MARIANAS. THIS IS ANTICIPATED TO
REMAIN THROUGH MUCH OF THE WORK WEEK. AROUND FRIDAY NIGHT, SHOWERS
ARE ANTICIPATED TO BUILD BACK IN AS A POTENTIAL DISTURBANCE MAY BRING
SHOWERS TO THE REGION FOR THE REST OF THE WEEKEND AND FIRST HALF OF
NEXT WEEK.
MARINE...
SEAS HAVE FALLEN TO 5 TO 7 FEET AND ARE ANTICIPATED TO REMAIN AROUND
THESE LEVELS THROUGH MUCH OF THE WORK WEEK. CURRENTLY A THIRD LONG
PERIOD SWELL IS BEING DETECTED ON THE IPAN BUOY. THIS SWELL IS
ANTICIPATED TO LINGER FOR THE NEXT DAY OR SO. SEAS ARE ANTICIPATED
TO BUILD UP TO 10 FEET AGAIN FOR THE WEEKEND AS A POTENTIAL
DISTURBANCE MAY MOVE INTO THE REGION. WINDS ARE EXPECTED TO REMAIN
GENTLE TO MODERATE THROUGH FRIDAY, THEN MAY BUILD TO MODERATE TO
FRESH AS THE DISTURBANCE PASSES.
HYDROLOGY...
TOWARDS THE END OF THE WEEK WE WILL BE WATCHING A DISTURBANCE DEVELOP
ACROSS WESTERN MICRONESIA. ENSEMBLE GUIDANCE IS IN FAIRLY GOOD
AGREEMENT ON A MONSOON-LIKE PATTERN DEVELOPING WITH THIS DISTURBANCE.
THIS CHANGE TO WIDESPREAD WESTERLY WINDS WILL ALLOW FOR AN INCREASE
IN SHOWER AND THUNDERSTORM ACTIVITY ACROSS THE MARIANAS. GUIDANCE
SHOWS POTENTIAL FOR HEAVY RAINFALL ACROSS ALL OF THE MARIANAS AS
EARLY AS FRIDAY NIGHT AND LASTING THROUGH AT LEAST TUESDAY. IF THESE
TRENDS CONTINUE, ADDITIONAL HYDROLOGIC AND FLOOD PRODUCTS MAY BE
ISSUED OVER THE COMING DAYS. THE THREAT FOR MUDSLIDES WILL ALSO BE
INCREASED DUE TO ANTECEDENT CONDITIONS SATURATING SOILS. THOSE IN
THE MARIANAS SHOULD CONTINUE TO MONITOR FORECASTS OVER THE COMING
DAYS FOR MORE DETAILS.
EASTERN MICRONESIA...
THE MAIN FORECAST CHALLENGE WAS DETERMINING WHEN TO INCREASE POPS
(PROBABILITY OF PRECIPITATION) FOR POHNPEI AND KOSRAE. KOSRAE IS ON
THE SOUTHERN EDGE OF THE DEEPER MOISTURE CURRENTLY, WITH BOTH
POHNPEI AND KOSRAE LACKING A TRIGGER (LIGHT WINDS AND WEAK SURFACE
CONVERGENCE IS PRESENT CURRENTLY), ALTHOUGH POHNPEI IS SEEING SOME
MID TO HIGH-LEVEL CLOUD DEBRIS FROM A NEAR-EQUATORIAL TROUGH (NET)
TO THE SOUTH. WITH THAT SAID, MOISTURE DEPTH AND SURFACE CONVERGENCE
WILL LEAD TO INCREASING RAINFALL POTENTIAL BY THURSDAY, CONTINUING
THROUGH THE WEEKEND. MEANWHILE, MAJURO CONTINUES TO SEE MOSTLY CLOUDY
SKIES WITH SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS CONTINUING
INTO THE WEEKEND.
AS FOR MARINE CONDITIONS, LIGHT TO GENTLE WINDS AT POHNPEI AND MAJURO
WILL INCREASE INTO THE GENTLE TO MODERATE RANGE FOR THE LATTER HALF
OF THE WEEK, WITH KOSRAE GENERALLY KEEPING LIGHT TO GENTLE WINDS FOR
MOST OF THE FORECAST PERIOD. SEAS WILL HOLD IN THE 5 TO 7 FOOT RANGE.
WESTERN MICRONESIA...
THE LATEST SATELLITE DATA SHOWS CLOUDY SKIES WITH NUMEROUS SHOWERS
AND ISOLATED THUNDERSTORMS ACROSS CHUUK. PALAU HAS MOSTLY CLOUDY
SKIES WITH SCATTERED SHOWERS WHILE YAP PROPER IS SEEING PARTLY CLOUDY
SKIES AND SPOTTY SHOWERS. ALTIMETRY SHOWS SEAS OF 4 TO 6 FEET FOR
YAP AND 5 TO 7 FEET FOR CHUUK. NO CURRENT ALTIMETRY PASS IS
AVAILABLE FOR PALAU.
AS HAS BEEN THE CASE FOR THE LAST FEW DAYS, THE NET REMAINS THE
PRIMARY WEATHER PRODUCER ACROSS WESTERN MICRONESIA. AS WAS MENTIONED
YESTERDAY, THE FORECAST WILL BE CHANGEABLE OVER THE NEXT FEW DAYS
UNTIL THE EVOLUTION OF THE EXPECTED DISTURBANCE BECOMES MORE
ORGANIZED. THE LATEST MODEL GUIDANCE NOW SHOWS A VERY WET PATTERN
OVER WENO THROUGH THE NEXT FEW DAYS AS A DISTURBANCE DEVELOPS TO THE
SOUTH OF CHUUK AND MOVES TOWARD YAP PROPER. ON THE OTHER SIDE,
GUIDANCE SHOWS VERY DRY CONDITIONS FOR YAP AND PALAU FOR THE NEXT
COUPLE OF DAYS. BASED ON SATELLITE TRENDS, INCREASED SHOWERS AT
CHUUK FOR THE NEXT COUPLE OF DAYS, HOWEVER, DECIDED NOT TO DROP
SHOWER COVERAGE FOR YAP AND PALAU, AS MODEL GUIDANCE IS STILL
QUESTIONABLE. FORECASTS SHOULD SETTLE A BIT OVER THE NEXT DAY OR TWO
AS CONFIDENCE INCREASES AND MODEL GUIDANCE COMES MORE IN SYNCH.
RESIDENTS OF PALAU, YAP AND CHUUK SHOULD MONITOR FORECASTS CLOSELY
OVER THE NEXT FEW DAYS FOR UPDATED CONDITIONS.
FOR THE MARINE FORECAST, THE ONLY MAJOR CHANGE OVER THE NEXT FEW
DAYS IS THE ARRIVAL OF A LONGER PERIOD NORTH SWELL BEGINNING
WEDNESDAY AND BUILDING A BIT INTO THE WEEKEND. THE NORTH SWELL COULD
BECOME THE PRIMARY SWELL AS EARLY AS FRIDAY NIGHT FOR YAP AND CHUUK,
BUT THIS IS CONTINGENT ON THE DEVELOPMENT OF THE EXPECTED TROPICAL
DISTURBANCE OVER THE NEXT FEW DAYS. SEAS COULD REACH SMALL CRAFT
ADVISORY LEVELS OVER THE WEEKEND.
GUM WATCHES/WARNINGS/ADVISORIES
GU...NONE.
MP...NONE.
MARIANAS WATERS...NONE.
MARIANAS/EAST AND WEST MICRONESIA UPDATE: CRUZ/WHISNANT
MARIANAS: BOWSHER
EAST MICRONESIA: DOLL
WEST MICRONESIA: KLEESCHULTE
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