343
FXPQ50 PGUM 052034
AFDGUM
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TIYAN GU
634 AM CHST FRI MAR 6 2026
MARIANAS UPDATE
SATELLITE AND RADAR THIS MORNING SHOW LINES OF SHOWERS OVER THE
SOUTHERN COASTAL WATERS OF GUAM, CRAWLING WEST-SOUTHWEST, WITH
ISOLATED SHOWERS ACROSS THE CNMI. THERE WAS LITTLE CHANGE IN THE
PUBLIC AND MARINE FORECASTS. GUAM AND ROTA ARE EXPECTED TO SEE LOW-
END SCATTERED SHOWERS (30 PERCENT) TODAY, BUILDING WITHIN THE
CONVERGENCE ALONG THE FAR NORTHERN PERIPHERY OF INVEST 95W, THEN
INCREASING TO NUMEROUS SHOWERS TONIGHT AS THE DISTURBANCE SHIFTS TO
THE NORTHWEST. SHOWERS WERE DECREASED TO ISOLATED IN THE FORECAST
TODAY FOR TINIAN AND SAIPAN, BUILDING TO HIGH-END SCATTERED (50
PERCENT CHANCE) LATE TONIGHT. WINDS WILL BE MODERATE TO STRONG,
BECOMING BREEZY THROUGH THE NEXT FEW DAYS. ALTIMETRY CURRENTLY
DEPICTS COMBINED SEAS AROUND 6 TO 9 FEET OVER AND JUST WEST OF
COASTAL WATERS.
TROPICAL SYSTEMS UPDATE
SATELLITE THIS MORNING CONTINUES TO DEPICT A WEAK, HIGHLY
DISORGANIZED INVEST 95W, CURRENTLY CENTERED OVER YAP STATE SOUTH OF
THE MARIANAS, NEAR 5.5N 146.9E. CONVECTION IS SEEING A SLIGHT
INCREASE ABOUT THE CENTER EARLY THIS MORNING, ESPECIALLY NEAR AND
NORTHWEST OF CHUUK WHERE IT INTERACTS WITH A CONNECTING TRADE-WIND
TROUGH, AND WESTWARD ALONG THE AXIS OF THE NEAR-EQUATORIAL TROUGH
SOUTH OF PALAU. INVEST 95W IS STILL RATED "SUB-LOW" FOR DEVELOPMENT,
MEANING THAT SIGNIFICANT DEVELOPMENT INTO A TROPICAL CYCLONE
(TROPICAL DEPRESSION) IS NOT EXPECTED OVER THE NEXT FEW DAYS. THE
DISTURBANCE IS EXPECTED TO MOVE NORTHWEST OVER THE NEXT DAY OR SO
WITH LITTLE TO SLOW DEVELOPMENT, THEN TURN NORTHWARD THIS WEEKEND AS
IT BEGINS TO INTERACT WITH A SHEAR LINE DROPPING SOUTHWARD TOWARDS
THE MARIANAS. THE HEAVIER CONVECTION LOOKS TO REMAIN NORTH AND
NORTHEAST OF THE CENTER OF INVEST 95W, ESPECIALLY AS IT STARTS TO
INTERACT WITH THE SHEAR LINE. THIS MAY LEAD TO HEAVY RAINFALL, BREEZY
WINDS, CHOPPY SEAS, AND STRONGER GUSTS ACROSS THE MARIANAS THROUGH
THE NEXT FEW DAYS, STARTING LATE TONIGHT.
EASTERN MICRONESIA UPDATE
THERE WAS LITTLE CHANGE TO THE FORECAST. SATELLITE DEPICTS ISOLATED
TO SCATTERED SHOWERS ACROSS THE REGION. SHOWERS WERE DECREASED
SLIGHTLY FOR POHNPEI TODAY (30 PERCENT TO 20 PERCENT) AND INCREASED
SLIGHTLY FOR KOSRAE (30 PERCENT TO 40 PERCENT) TO ALIGN WITH LATEST
SATELLITE AND MODEL TRENDS. LATEST SATELLITE ALTIMETRY INDICATES
COMBINED SEAS AROUND 6 TO 8 FEET.
WESTERN MICRONESIA UPDATE
A HEADLINE WAS INCLUDED FOR CHUUK TODAY AND TONIGHT, AS HIGHER WINDS
AND STRONG GUSTS ARE EXPECTED TO ACCOMPANY NUMEROUS TO WIDESPREAD
LOCALLY HEAVY SHOWERS THROUGH TONIGHT, GENERATING CHOPPY SEAS ACROSS
COASTAL WATERS. HOWEVER, SHOWERS WERE DECREASED TO 70 PERCENT TODAY
AND 80 PERCENT FOR TONIGHT TO ALIGN WITH SATELLITE AND MODEL TRENDS
THIS MORNING. OTHERWISE, THERE WAS LITTLE CHANGE TO THE FORECAST.
PREV DISCUSSION
/ISSUED 636 PM CHST THU MAR 5 2026/
MARIANAS SYNOPSIS...
SATELLITE IMAGERY AND RADAR SHOW MOSTLY CLEAR TO PARTLY CLOUDY SKIES
ACROSS THE MARIANAS WITH A FEW ISOLATED SHOWERS PRESENT. ALTIMETRY
AND BUOY DATA SHOW COMBINED SEAS BETWEEN 6 AND 8 FEET.
DISCUSSION...
KEY MESSAGES:
* DRY CONDITIONS LOOK TO PREVAIL THROUGH FRIDAY AFTERNOON ACROSS THE
MARIANAS, WITH SHOWERS BUILDING INTO THE REGION FRIDAY EVENING.
* HEAVY TO VERY HEAVY RAINFALL WILL BE POSSIBLE FRIDAY NIGHT AND
THROUGH THE WEEKEND AS INVEST 95W MOVES NEAR THE MARIANAS.
* THE FORECAST RELIES ON THE POSITIONS AND STRENGTH OF A TROPICAL
DISTURBANCE, WHICH COULD LEAD TO SIGNIFICANT CHANGES.
THE MAIN CHANGE WITH THIS PACKAGE WAS TO ADJUST THE TIMING OF HEAVY
RAINFALL ACROSS THE MARIANAS. THE ONSET OF THE EVENT APPEARS TO STILL
BE FRIDAY NIGHT, BUT THE HEAVIEST RAINFALL LOOKS TO FALL THIS WEEKEND
WHERE RAIN COULD BE VERY HEAVY AT TIMES. A FLASH FLOOD WATCH WAS
ISSUED FOR THE MARIANAS, SEE HYDROLOGY SECTION FOR MORE DETAILS.
AFTER A BRIEF EASTWARD TREND IN QPF, MODELS HAVE BEGUN TO TREND
TOWARDS THE WEST SOME, WHICH LINES UP THE HEAVIEST PRECIPITATION
ALONG THE MARIANAS. SHOWERS AND THUNDERSTORMS WILL IMPACT THE
MARIANAS THROUGH MUCH OF THE WEEK, ONLY TAPERING OFF DURING THE LATE
WEEK PERIOD.
MARINE...
A LONG PERIOD NORTH-SWELL HAS BEEN IMPACTING THE MARIANAS. COMBINED
SEAS OF 6 TO 8 FEET. THIS NORTH SWELL WILL BE RE-INVIGORATED AS A
SHEAR LINE MOVES SOUTHWARD TOWARDS THE CNMI. SEA CONDITIONS ARE SET
TO RISE THROUGH FRIDAY AFTERNOON, AS SEAS BECOME HAZARDOUS TO SMALL
CRAFT. SURF IS EXPECTED TO REMAIN HAZARDOUS ALONG NORTH FACING REEFS
THROUGH MONDAY AFTERNOON.
HYDROLOGY...
A BROAD TROPICAL DISTURBANCE WILL INTERACT WITH A SHEAR LINE,
IMPACTING THE MARIANAS LATE THIS WEEK, THROUGH THE WEEKEND, AND INTO
NEXT WEEK. SEVERAL ROUNDS OF HEAVY TO VERY HEAVY RAINFALL WILL BE
POSSIBLE DURING THIS TIME FRAME. THIS COULD LEAD TO 5 TO 10 INCHES OF
RAIN ACROSS THE MARIANAS WITH LOCALLY HEAVY AMOUNTS. DUE TO THE WET
ANTECEDENTS FROM EARLY THIS WEEK, THE CONDITIONS FOR FLASH FLOODING
COULD BE MET AT A LOWER THRESHOLD.
TROPICAL SYSTEMS...
A WEAK DISTURBANCE, BEING MONITORED AS INVEST 95W BY THE JOINT
TYPHOON CENTER (JTWC), IS A LOOSELY DEFINED, ELONGATED CIRCULATION
NEAR 5N150E WITH A TROUGH EXTENDING NORTH-NORTHEAST, PASSING NEAR
CHUUK LAGOON. CONVECTION REMAINS POORLY ORGANIZED AROUND THE
DISTURBANCE, WITH THE HEAVIER SHOWERS AND ISOLATED THUNDERSTORMS
FOUND NORTH OF THE CIRCULATION AND ALONG THE TROUGH FROM JUST NORTH
OF CHUUK LAGOON AND EXTENDING WESTWARD INTO EASTERN YAP STATE. INVEST
95W IS CURRENTLY RATED "SUB LOW" FOR DEVELOPMENT, MEANING THAT
SIGNIFICANT DEVELOPMENT INTO A TROPICAL CYCLONE (TROPICAL DEPRESSION)
IS NOT EXPECTED THE NEXT FEW DAYS. INVEST 95W IS EXPECTED TO MOVE
WEST-NORTHWEST OVER THE NEXT FEW DAYS WITH LITTLE TO VERY SLOW
DEVELOPMENT. THE HEAVIER CONVECTION WILL LIKELY REMAIN NORTH OF THE
CENTER OF INVEST 95W, ESPECIALLY AS IT STARTS TO INTERACT WITH A
SHEAR LINE DROPPING SOUTHWARD TOWARDS THE MARIANAS THIS WEEKEND. THIS
MAY LEAD TO HEAVY RAINFALL, BREEZY WINDS, CHOPPY SEAS, AND STRONGER
GUSTS ACROSS THE MARIANAS, ESPECIALLY IN HEAVIER SHOWERS AND
THUNDERSTORMS.
EASTERN MICRONESIA...
SATELLITE IMAGERY SHOWS ISOLATED SHOWERS AROUND POHNPEI AND KOSRAE,
INCREASING TO SCATTERED SHOWERS EAST OF KOSRAE ALONG A SERIES OF
WEAK-TRADE WIND TROUGHS, AND AROUND MAJURO WHERE A ILL-DEFINED
INTERTROPICAL CONVERGENCE ZONE (ITCZ) THEN EXTENDS FROM NEAR MAJURO
TO AT LEAST THE DATE LINE. SCATTEROMETER DATA FROM THIS MORNING
SHOWED SOME WINDS AROUND 25 TO 30 KT WITHIN THE ITCZ, LIKELY
CONVECTIVE GUSTS ASSOCIATED WITH SHOWERS, SO ADDED OCCASIONAL GUSTS
TO 25 KT TO MAJURO FORECAST FOR TONIGHT AND FRIDAY. MODEL GUIDANCE
SHOWS THE ITCZ SHIFTING WESTWARD TOWARDS KOSRAE AND POHNPEI, BEFORE
FRAGMENTING INTO A SERIES OF TRADE-WIND TROUGHS. THIS SHOULD SUPPORT
PERIODS OF SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS ACROSS THE
REGION THROUGH THE WEEKEND. THE GFS DOES START TO SUPPORT DRIER
CONDITIONS FOR MAJURO LATE THIS WEEKEND, THOUGH THE ECMWF CONTINUES
SHOWERS INTO EARLY NEXT WEEK, SO FOR NOW THE FORECAST IS A BLEND OF
BOTH GUIDANCES AND THE FORECAST WILL TREND TOWARDS WHICH MODEL
APPEARS TO BE HANDLING THE OVERALL PATTERN BETTER.
ALTIMETRY AND BUOY DATA SHOWS SEAS ARE AROUND 6 TO 7 FEET, DRIVEN BY
A LONG-PERIOD NORTH SWELL AND BACKGROUND EASTERLY SWELL. POHNPEI
BUOY, DRIFTING BUOYS, AND MODEL GUIDANCE SHOWS SURF ARE ELEVATED
ALONG NORTH FACING REEFS OF POHNPEI, KOSRAE, AND MAJURO BUT ARE JUST
BELOW THE 9 FOOT THRESHOLD FOR POHNPEI AND KOSRAE AND WELL BELOW THE
12 FEET FOR MAJURO. SEAS AND SURF ARE EXPECTED TO REMAIN FAIRLY
STEADY THROUGH SATURDAY, BUT SATURDAY NIGHT INTO SUNDAY, ANOTHER
LONG-PERIOD NORTH SWELL, GENERATED BY A DISTANT SYSTEM NEAR JAPAN,
WILL MOVE THROUGH THE REGION AND WILL LIKELY CAUSE SURF TO BECOME
HAZARDOUS ALONG NORTH FACING REEFS AT POHNPEI AND KOSRAE, AND WILL
APPROACH HAZARDOUS LEVELS AT MAJURO. THE POTENTIAL OF NUISANCE
COASTAL FLOODING AT MAJURO WILL CONTINUE THROUGH FRIDAY AS HIGH TIDES
REMAIN ELEVATED FOLLOWING THE FULL MOON PHASE THAT OCCURRED AROUND
TUESDAY NIGHT.
WESTERN MICRONESIA...
THE MAIN FEATURES IMPACTING THE FORECAST FOR WESTERN MICRONESIA ARE
THE NEAR-EQUATORIAL TROUGH (NET) AND INVEST AREA 95W WHICH IS WITHIN
THE NET, AS WELL AS TROUGHS BRANCHING OFF FROM BOTH THE NET AND 95W.
CHUUK WILL EXPERIENCE SCATTERED SHOWERS THIS EVENING, WHICH COULD
RAMP UP AFTER MIDNIGHT TO WIDESPREAD, REMAINING SO THROUGH FRIDAY
NIGHT, THEN SCATTERED SATURDAY, NUMEROUS SATURDAY NIGHT, THEN
SCATTERED THROUGH MONDAY. SATELLITE IMAGERY DOESN'T SEEM SUGGESTIVE
OF THAT KIND OF WET WEATHER, THE NWP GUIDANCE IS ADAMANT THOUGH, WITH
3 INCHES OF RAIN OVER THE NEXT COUPLE OF DAYS. WINDS WILL BE 10 TO 15
KNOTS THROUGH SATURDAY, THEN 5 TO 10 KNOTS THROUGH TUESDAY. SEAS WILL
BE 5 TO 7 FEET TONIGHT GRADUALLY DIMINISHING TO BETWEEN 4 AND 6 FEET
BY TUESDAY. THIS WILL GENERALLY LEAD TO BENIGN MARINE CONDITIONS.
YAP WILL HAVE ISOLATED SHOWERS TONIGHT, THEN SCATTERED SHOWERS FOR
THE REST OF THE PERIOD, THROUGH TUESDAY. WINDS WILL BE 10 TO 15 KNOTS
THROUGH SATURDAY, THEN 5 TO 10 KNOTS THROUGH TUESDAY. SEAS WILL BE 5
TO 7 FEET THROUGH FRIDAY NIGHT, THEN 6 TO 8 FEET THROUGH MONDAY, AND
MAYBE 7 TO 9 FEET TUESDAY. THIS WILL LEAD TO BENIGN CONDITIONS
THROUGH THE WEEKEND, WHICH COULD BECOME CHALLENGING MONDAY OR
TUESDAY.
KOROR, PALAU WILL SEE ISOLATED SHOWERS THROUGH SATURDAY AS THE NET
REMAINS SOUTH OF THEM, THEN SCATTERED SHOWERS THROUGH TUESDAY AS IT
APPROACHES. WINDS WILL BE 5 TO 10 KNOTS THROUGH SATURDAY, THEN 5
KNOTS THROUGH TUESDAY. SEAS WILL BE 4 TO 6 FEET THROUGH SATURDAY
NIGHT, THEN 5 TO 7 FEET THROUGH TUESDAY. THESE WILL LEAD TO BENIGN
MARINE CONDITIONS THROUGH THE PERIOD.
GUM WATCHES/WARNINGS/ADVISORIES
GU...HIGH RIP CURRENT RISK THROUGH MONDAY AFTERNOON FOR GUZ001.
HIGH SURF ADVISORY UNTIL 4 PM CHST MONDAY FOR GUZ001.
FLOOD WATCH FROM LATE TONIGHT THROUGH TUESDAY MORNING FOR GUZ001.
MP...HIGH RIP CURRENT RISK THROUGH MONDAY AFTERNOON FOR MPZ001>003.
HIGH SURF ADVISORY UNTIL 4 PM CHST MONDAY FOR MPZ001>003.
FLOOD WATCH FROM LATE TONIGHT THROUGH TUESDAY MORNING FOR
MPZ001>003.
MARIANAS WATERS...SMALL CRAFT ADVISORY FROM 7 PM THIS EVENING TO 5 PM CHST SUNDAY FOR
PMZ151>154.
MARIANAS/EAST AND WEST MICRONESIA/TROPICAL UPDATE: DECOU
MARIANAS: WILLIAMS
EAST MICRONESIA: SCHANK
WEST MICRONESIA: STANKO
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