755
FXPQ50 PGUM 251957
AFDGUM
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TIYAN GU
557 AM CHST THU MAR 26 2026
MARIANAS UPDATE
MOSTLY CLOUDY SKIES WITH ISOLATED SHOWERS NEAR GUAM AND ROTA AND
SCATTERED SHOWERS NEAR TINIAN AND SAIPAN WILL CONTINUE TODAY. BRIEFLY
SHOWERS COULD GO SCATTERED TONIGHT AT GUAM AND ROTA. WINDS HAVE
DIMINISHED, SO ALLOWED THE SMALL CRAFT ADVISORY TO EXPIRE. THIS WAS
IN GOOD AGREEMENT WITH THE PREVIOUS FORECAST PACKAGE, SO ONLY MINOR
UPDATES WERE NEEDED.
EASTERN MICRONESIA UPDATE
TOOK MAJURO DOWN FROM NUMEROUS SHOWERS TO SCATTERED, AS THE BULK OF
THE ACTIVITY HAS MOVED WEST OF THEM. ALSO TOOK OUT THE HEAVY WORDING.
POHNPEI AND KOSRAE WERE HOLDING UP WELL, SO LITTLE CHANGE FOR THEM.
WESTERN MICRONESIA UPDATE
CHUUK WILL HAVE WINDS OF 5 KNOTS, SEAS OF 3 TO 5 FEET, AND ISOLATED
SHOWERS THROUGH MONDAY.
YAP WILL HAVE WINDS OF 5 TO 15 KNOTS, SEAS OF 3 TO 5 FEET (EXCEPT 4
TO 6 TODAY), AND SCATTERED SHOWERS TODAY, BECOMING ISOLATED TONIGHT,
AND STAYING THAT WAY FOR THE REST OF THE WEEK.
KOROR, PALAU WILL HAVE WINDS OF 5 TO 15 KNOTS, SEAS OF 3 TO 5 FEET,
AND SCATTERED SHOWERS THROUGH FRIDAY, THEN ISOLATED SHOWERS THROUGH
MONDAY.
PREV DISCUSSION
/ISSUED 631 PM CHST WED MAR 25 2026/
MARIANAS SYNOPSIS...
SATELLITE OBSERVATIONS SHOW SCATTERED SHOWERS MOVING THROUGH THE
CNMI, DUE TO A SURGE IN THE TRADE-WINDS ALONG A SHEAR LINE FRAGMENT.
ADDITIONALLY, AN AREA OF DEEPENING CONVECTION IS OCCURRING EAST OF
THE REGION AROUND A WEAK CIRCULATION WITHIN A BROAD NEAR-EQUATORIAL
TROUGH PATTERN. A SMALL CRAFT ADVISORY IS IN EFFECT FOR TINIAN AND
SAIPAN AS MODERATE TO STRONG NORTHEAST TO EAST WINDS WITH NEAR-GALE
GUSTS CONTINUE THROUGH TONIGHT. FARTHER SOUTH, WINDS ARE LIGHT TO
MODERATE AT GUAM AND ROTA, WITH OCCASIONAL STRONG GUSTS EXPECTED
ACROSS ROTA WATERS TONIGHT. DAYTIME ALTIMETRY PASSES SHOW SEAS AROUND
5 TO 8 FEET AND UP TO 9 FEET EAST OF SAIPAN.
DISCUSSION...
AN UNSETTLED PATTERN REMAINS ACROSS THE REGION. CONVERGENT FLOW
NORTH OF A NEAR-EQUATORIAL TROUGH (NET) AND EMBEDDED DISTURBANCES,
WILL BRING PERIODS OF SCATTERED SHOWERS TO THE MARIANAS OVER THE NEXT
FEW DAYS. SATELLITE OBSERVATIONS INDICATE SHOWERS ARE INTENSIFYING
OVER A CIRCULATION TO OUR EAST, HOWEVER, THERE IS SOME UNCERTAINTY IN
ITS OVERALL ORGANIZATION AND DEVELOPMENT IN CURRENT MODEL GUIDANCE.
THE BULK OF CONVECTION LOOKS TO BE ON THE EASTERN SIDE OF THIS
DISTURBANCE, WELL EAST OF THE MARIANAS. HOWEVER, THIS WEAK
CIRCULATION REMAINS NEARBY OVER THE NEXT FEW DAYS, SO HAVE BUMPED UP
THE POPS (PROBABILITY OF PRECIPITATION) THROUGH FRIDAY. ALSO, ADDED
ISOLATED THUNDERSTORMS AND LOCALLY HEAVY SHOWERS POSSIBLE TONIGHT,
BUT WILL NEED TO MONITOR SATELLITE AND MODEL TRENDS IF THIS NEEDED
FOR THURSDAY AS WELL. LATER ON, MODELS HINT AT ANOTHER SHEAR LINE
FRAGMENT, BRINGING ISOLATED TO SCATTERED SHOWERS TO THE CNMI EARLY
NEXT WEEK. THEN, A RETURN TO A MORE SUBDUED TRADE-WIND PATTERN IS
EXPECTED NEXT WEEK AS NEARBY FEATURES WEAKEN AND THERE IS A SOUTHWARD
SHIFT IN THE NET.
MARINE/SURF...
MODERATE TO STRONG WINDS WITH NEAR-GALE GUSTS ARE PRODUCING
HAZARDOUS CONDITIONS FOR SMALL CRAFT OPERATIONS FOR TINIAN AND SAIPAN
THROUGH TONIGHT. FARTHER SOUTH, WINDS ARE LIGHT TO MODERATE AT GUAM
AND ROTA, WITH OCCASIONAL STRONG GUSTS EXPECTED ACROSS ROTA WATERS
TONIGHT. AFTERWARDS, WINDS ARE EXPECTED TO DIMINISH TO LIGHT TO
MODERATE THROUGH EARLY NEXT WEEK. COMBINED SEAS BETWEEN 4 AND 8 FEET
GRADUALLY DECREASE TO 3 TO 5 FEET LATE WEEK, THEN ANOTHER PULSE OF
NORTHERLY SWELL IS EXPECTED TO INCREASE SEAS BACK UP TO 4 TO 7 FEET
EARLY NEXT WEEK. A MODERATE RISK OF RIP CURRENTS CONTINUES ALONG
NORTH AND EAST FACING REEFS FOR AT LEAST THE NEXT SEVERAL DAYS, WHILE
REMAINING LOW ALONG SOUTH AND WEST FACING REEFS. WITH THE ARRIVAL OF
NORTHERLY SWELL, AN INCREASE SURF ALONG NORTH-FACING REEFS LATE WEEK
AND OVER THE WEEKEND, BUT SURF IS NOT REACH HAZARDOUS LEVELS OF 9
FEET AT THIS TIME. REFRACTED SWELL ENERGY MAY ALSO ADD A FOOT OR TWO
TO SURF ALONG WEST-FACING REEFS, POSSIBLY INCREASING THE RIP RISK TO
MODERATE OVER THE WEEKEND.
EASTERN MICRONESIA...
LATEST SATELLITE IMAGERY SHOWS PARTLY CLOUDY SKIES WITH ISOLATED
SHOWERS OVER POHNPEI AND KOSRAE, AND MOSTLY CLOUDY SKIES WITH
SCATTERED SHOWERS AT MAJURO. CLOUDY SKIES WITH NUMEROUS SHOWERS AND
ISOLATED THUNDERSTORMS ARE EAST OF MAJURO AND EXPECTED TO APPROACH
OVERNIGHT.
KOSRAE LOOKS TO REMAIN THE DRIEST LOCATION OVER THE NEXT SEVERAL
DAYS. THERE ARE TWO MAIN FEATURES AFFECTING THE REGION, AN INTER-
TROPICAL CONVERGENCE ZONE (ITCZ) AND A NEAR-EQUATORIAL TROUGH (NET).
KOSRAE WILL BE RIGHT IN THE MIDDLE OF THE TWO, KEEPING MOST OF THE
CONVECTION BOTH EAST AND WEST OF KOSRAE THROUGH MOST OF THE FORECAST
PERIOD. FOR MAJURO, THE ITCZ IS PRESENT TO THE NORTH OF THE ATOLL,
WITH A TRADE-WIND TROUGH APPROACHING FROM THE EAST. THIS TROUGH IS
INTERACTING WITH THE ITCZ TO GENERATE NUMEROUS SHOWERS AND ISOLATED
THUNDERSTORMS TO THE EAST OF MAJURO. THIS TROUGH WILL APPROACH SLOWLY
OVER THE NEXT FEW HOURS, WITH THE GFS SHOWING THE TROUGH BECOMING A
WEAK CIRCULATION TO THE SOUTH OF THE ATOLL. THIS SHOULD MAINTAIN
NUMEROUS SHOWERS AND ISOLATED THUNDERSTORMS ACROSS MAJURO THROUGH
THURSDAY AFTERNOON. LATER, MODEL CONSENSUS KEEPS THE ITCZ ACROSS THE
MARSHALLS, MAINTAINING AN UNSTABLE PATTERN THROUGH THE BEGINNING OF
NEXT WEEK.
FOR POHNPEI, SCATTERED SHOWERS ALONG THE NET WEST OF POHNPEI ARE
EXPECTED TO BACKBUILD INTO POHNPEI OVERNIGHT, WITH SHOWERS BECOMING
SCATTERED AFTER MIDNIGHT. THEN, A WEAKER TRADE-WIND TROUGH, CURRENTLY
WEST OF KWAJALEIN, WILL APPROACH POHNPEI, MAINTAINING A WET PATTERN
THERE FOR THE NEXT FEW DAYS. THIS TROUGH LOOKS TO PASS THROUGH TO
THE NORTH OF KOSRAE, POSSIBLY BRINGING A BRIEF PERIOD OF LOW-END
SCATTERED SHOWERS TO THE ISLAND FRIDAY NIGHT. BY THE WEEKEND, THE
TROUGH LOOKS TO MOVE WEST OF POHNPEI, WITH DECREASING CONVECTION
ACROSS THE STATE. A SHORT PERIOD OF SCATTERED SHOWERS IS EXPECTED
SUNDAY.
BENIGN MARINE CONDITIONS LOOK TO CONTINUE THROUGH THE BEGINNING OF
NEXT WEEK, WITH COMBINED SEAS OF 3 TO 5 FEET FOR KOSRAE AND POHNPEI.
SEAS OF 3 TO 5 FEET WILL ALSO CONTINUE AT MAJURO INTO THE WEEKEND,
THEN BUILD A BIT, REACHING 5 TO 7 FEET EARLY NEXT WEEK. MOSTLY LIGHT
TO GENTLE WINDS ARE EXPECTED THROUGH THE WEEKEND.
WESTERN MICRONESIA...
THE MAIN FEATURE IN THE REGIONS REMAINS THE NEAR EQUATORIAL TROUGH
(NET) WITH AN EMBEDDED CIRCULATION (WITH LITTLE CHANCE OF
DEVELOPMENT). THE NET ENTERS THE REGION NEAR 4N130E AND EXTENDS
NORTHEAST THROUGH THE DISTURBANCE NEAR 8N137E AND CONTINUES TO EXTEND
NORTHEAST UNTIL IT EXITS WESTERN MICRONESIA NEAR 10N142E. IT RE-
ENTERS THE REGION NEAR 10N151E AND CONTINUES SOUTHEAST PASSING
BETWEEN CHUUK AND POHNPEI AS IT ENTERS EASTERN MICRONESIA. THE
EMBEDDED DISTURBANCE IS LOCATED TO THE SOUTHWEST OF NGULU AND COASTAL
WATERS. YAP PROPER CAN EXPECT TO SEE SCATTERED SHOWERS DUE TO BEING
IN THE INFLOW OF THIS DISTURBANCE. WHILE PALAU IS NEAR THE NET AXIS
AND CAN EXPECTED TO SEE SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS.
THESE SHOWERS ARE ANTICIPATED TO LINGER FOR THE NEXT DAY OR SO. ONCE
THIS FEATURE MOVES SOUTHWARD, BOTH LOCATIONS ARE ANTICIPATED TO
RETURN TO A DRIER PATTERN.
CHUUK LIES NEAR WHERE THE NET RE-ENTERS THE REGION. WITH THE NET
NEARBY, SHOWERS ARE EXPECTED TO BUILD IN TONIGHT. THESE SHOWERS ARE
BEING PRODUCED BY THE CONVERGENCE OF THE NET AND THE TRADE-WIND FLOW.
THE NET IS ANTICIPATED TO SHIFT SOUTH OF CHUUK OVER THE WEEKEND.
MEANWHILE, A DRIER PATTERN IS EXPECTED TO RETURN AS WINDS WEAKEN AND
AN AREA DIFFLUENT FLOW SETS UP BETWEEN THE MAIN WEATHER FEATURES IN
THE REGION.
MARINE CONDITIONS ARE MOST ELEVATED NEAR THE DISTURBANCE NEAR YAP
PROPER WITH COMBINED SEAS OF 5 TO 6 FEET. SATELLITE IMAGERY SHOWS A
LOT OF SUN GLINT OVER MUCH OF WESTERN MICRONESIA, WHICH SUGGESTS THE
OCEAN HAS LITTLE TO NO WIND WAVES. ALTIMETRY SHOWS COMBINED SEAS 4
TO 5 FEET FOR THE REST OF THE REGION. WINDS ARE EXPECTED TO LIGHT TO
GENTLE FOR MUCH OF THE DOMAIN, AND GENTLE TO MODERATE NEAR THE
DISTURBANCE. OVER THE WEEKEND AN INCREASE IN NORTHERLY SWELL MAY
ARRIVE IN THE REGION. THIS COULD BUILD SURF LEVELS ALONG NORTH FACING
REEFS TO AROUND 8 FEET.
GUM WATCHES/WARNINGS/ADVISORIES
GU...NONE.
MP...NONE.
MARIANAS WATERS...NONE.
MARIANAS/EAST AND WEST MICRONESIA UPDATE: STANKO
MARIANAS: CRUZ
EAST MICRONESIA: KLEESCHULTE
WEST MICRONESIA: BOWSHER
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