641
FXPQ50 PGUM 251948
AFDGUM
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TIYAN GU
548 AM CHST MON OCT 26 2026
MARIANAS UPDATE
SHOWER COVERAGE IS EXPECTED TO RETURN TO ISOLATED TODAY FOR THE
MARIANAS AND CONTINUE FOR THE NEXT COUPLE OF DAYS. GENTLE TO
MODERATE EAST WINDS WILL WEAKEN TONIGHT, BECOMING MOSTLY LIGHT AND
NORTHEAST TUESDAY. LIGHT WINDS MAY ALLOW FOR ISLAND-EFFECT SHOWERS
TO OCCUR ON TUESDAY AND WEDNESDAY. COMBINED SEAS AROUND 6 FEET MAY
VERY SLOWLY DIMINISH THROUGH MIDWEEK. OTHERWISE, A MODERATE RISK OF
RIP CURRENTS CONTINUES ALONG NORTH, EAST, AND WEST-FACING REEFS
THROUGH AT LEAST TONIGHT.
TROPICAL SYSTEMS UPDATE
TROPICAL STORM IN-FA WAS UPGRADED TO A TYPHOON OVERNIGHT BY THE
JOINT TYPHOON WARNING CENTER. IN-FA IS CURRENTLY LOCATED NEAR 13.4N
163.9E THIS MORNING AND IS MOVING AROUND 10 MPH TO THE NORTH-
NORTHWEST. IT IS EXPECTED TO MAKE A SLIGHT TURN TOWARD THE NORTHWEST
WITH A DECREASE IN FORWARD SPEED THROUGH TUESDAY. IN-FA'S MAXIMUM
SUSTAINED WINDS HAVE INCREASED TO 85 MPH. IT IS FORECAST TO INTENSIFY
THROUGH TUESDAY. TYPHOON FORCE WINDS EXTEND OUTWARD FROM THE CENTER
UP TO 15 MILES. TROPICAL STORM FORCE WINDS EXTEND OUTWARD FROM THE
CENTER UP TO 80 MILES. THE GENERAL CONSENSUS AMONGST ENSEMBLE
GUIDANCE HAS TYPHOON IN-FA MOVING TOWARD THE FAR NORTHERN MARIANAS
LATE THIS WEEK.
FOR MORE INFORMATION ON TYPHOON IN-FA, PLEASE REFER TO BULLETINS
FROM THE JOINT TYPHOON WARNING CENTER UNDER WMO HEADER WTPN31 PGTW
AND FROM THE NATIONAL WEATHER SERVICE UNDER WMO HEADER WTPQ31 PGUM.
EASTERN MICRONESIA UPDATE
CONVERGENCE SOUTH OF TYPHOON IN-FA WILL CONTINUE TO PROMOTE PERIODS
OF SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS AT POHNPEI THROUGH AT
LEAST TODAY. CONDITIONS SHOULD IMPROVE STARTING TONIGHT FOR POHNPEI.
DRIER WEATHER IS EXPECTED TO PREVAIL AT KOSRAE AND MAJURO FOR THE
NEXT COUPLE OF DAYS. LIGHT TO MODERATE SOUTHWEST WINDS WILL CONTINUE
FOR THE NEXT DAY OR TWO AT KOSRAE AND MAJURO WITH MOSTLY GENTLE TO
MODERATE WEST WINDS PREVAILING AT POHNPEI. COMBINED SEAS OF 4 TO 6
FEET WILL CONTINUE FOR THE NEXT COUPLE OF DAYS, WITH SEAS SLOWLY
SUBSIDING AT MAJURO TO AROUND 4 FEET BY MIDWEEK.
WESTERN MICRONESIA UPDATE
GENERALLY QUIET WEATHER IS EXPECTED OVER THE NEXT COUPLE OF DAYS WITH
SHOWER CHANCES ONLY TOPPING OUT AROUND 30 PERCENT. WINDS WILL REMAIN
LIGHT TO GENTLE AT ALL FORECAST SITES THROUGH AT LEAST EARLY THIS
WEEK. COMBINED SEAS OF 3 TO 5 FEET WILL CONTINUE THROUGH TODAY AT ALL
FORECAST POINTS AND SEAS WILL BUILD A FOOT OR SO AT CHUUK OVER THE
NEXT COUPLE OF DAYS.
PREV DISCUSSION
/ISSUED 542 PM CHST SUN OCT 25 2026/
MARIANAS SYNOPSIS...
GENTLE TO MODERATE EASTERLY WINDS PREVAIL ACROSS THE MARIANAS THIS
EVENING. SCATTERED SHOWERS ARE VISIBLE ON RADAR AND SATELLITE, WITH
SLIGHTLY HIGHER COVERAGE OVER GUAM AND ROTA. MODEL AND OBSERVATION
DATA INDICATE COMBINED SEAS OF 6 TO 7 FEET.
DISCUSSION...
A WEAK LINE OF CONVERGENCE ASSOCIATED WITH A BROAD TROUGH CENTERED
NEAR PALAU AND EASTERLY TRADE WINDS IS SITTING OVER THE MARIANAS AND
BRINGING SCATTERED SHOWERS TO GUAM TONIGHT WITH ISOLATED
THUNDERSTORMS FOR ALL ISLANDS. THE RISK FOR ISOLATED THUNDERSTORMS
WILL CONTINUE THROUGH MONDAY MORNING FOR GUAM AS AN UPPER-LEVEL
TROUGH MOVES INTO THE REGION AND WIND SHEAR INCREASES SIGNIFICANTLY.
HOWEVER, A DIFFUSIVE LOW-LEVEL FLOW AND DRY UPPER-LEVEL AIR WILL
LIKELY KEEP STORM COVERAGE ISOLATED. BY MONDAY, THE UPPER-LEVEL
TROUGH WILL START TO MOVE OUT AND ONLY ISOLATED SHOWERS ARE
ANTICIPATED UNTIL FRIDAY NIGHT. AS WINDS DECREASE OVER THE NEXT
COUPLE OF DAYS, THE ONE EXCEPTION MAY BE FOR SCATTERED ISLAND-EFFECT
SHOWERS IN THE AFTERNOON OVER GUAM TUESDAY AND WEDNESDAY. CURRENT
TROPICAL STORM IN-FA IS EXPECTED TO MAKE IT'S CLOSEST POINT OF
APPROACH SOMETIME FRIDAY OR SATURDAY WHICH WILL BRING SCATTERED
SHOWERS FOR THE CNMI AND POTENTIALLY BREEZY CONDITIONS. THIS
SITUATION REMAINS HIGHLY UNCERTAIN, THOUGH MOST MODELS SHOW A PASSAGE
THROUGH THE REMOTE, FAR NORTHERN CNMI WITH MINIMAL IMPACTS TO THE
MARIANAS. THIS WILL CONTINUE TO BE MONITORED CLOSELY FOR ANY
POTENTIAL CHANGES. SEE THE "TROPICAL SYSTEMS" SECTION FOR MORE
DETAILS.
MARINE...
GENTLE TO MODERATE EASTERLIES WILL PREVAIL ACROSS THE MARIANAS
THROUGH MONDAY, THEN BEGIN TO LIGHTEN MONDAY NIGHT ESPECIALLY OVER
GUAM COASTAL WATERS. A TRADE-WIND CONVERGENCE ZONE WILL CONTINUE TO
BRING SCATTERED SHOWERS TONIGHT. ISOLATED THUNDERSTORMS WILL ALSO BE
POSSIBLE THROUGH EARLY MONDAY DUE TO INCREASED UPPER-LEVEL
INSTABILITY. THEREFORE, THERE IS A MODERATE RISK OF LIGHTNING ALONG
THE COASTLINES. COMBINED SEAS OF 6 FEET TONIGHT MAY DECREASE SLIGHTLY
WITH A DIMINISHING WEST SWELL BUT WILL OTHERWISE PERSIST WITH THE
DOMINANT EAST SWELL THROUGH THURSDAY. THIS IS CONTRIBUTING TO A
MODERATE RISK OF RIP CURRENTS ALONG WEST-, NORTH-, AND EAST- FACING
REEFS. BY FRIDAY, SEAS MAY INCREASE SIGNIFICANTLY AHEAD OF CURRENT
TROPICAL STORM IN-FA THAT IS ANTICIPATED TO PASS SOMEWHERE THROUGH
THE REMOTE, FAR NORTHERN CNMI ISLANDS.
TROPICAL SYSTEMS...
TROPICAL STORM IN-FA IS BEGINNING TO EXIT THE NORTHERN MARSHALL
ISLANDS, CURRENTLY CENTERED NEAR 11.8N 165.1E, OR ABOUT 190 MILES
EAST OF ENEWETAK ATOLL, 280 MILES NORTHWEST OF KWAJALEIN ATOLL, AND
1370 MILES EAST OF GUAM. HIMAWARI VISIBLE SATELLITE SHOWS AN AREA OF
DEEP CONVECTION ORGANIZED ABOUT THE CENTER, COVERING ENEWETAK AND
BIKINI ATOLLS, WITH PATCHY, DISCONTINUOUS OUTER RAINBANDS SEEN
WITHIN THE WESTERLY INFLOW TO ITS SOUTH AND SOUTHWEST, EXTENDING
ACROSS POHNPEI. CONVECTIVE BANDS EXTEND INTO THE NORTHEAST PORTION OF
THE STORM AS WELL, BUT THE INFLOW IS SOMEWHAT CUT OFF BY THE
PRESENCE OF A WEAKER CIRCULATION SEEN NEAR THE DATE LINE. IN-FA IS
FORECAST TO MOVE NORTHWEST THROUGH MONDAY WITH A FORWARD SPEED
AROUND 6 OR 7 MPH, SLOWING DOWN MONDAY NIGHT THROUGH TUESDAY AS ITS
TRACK SHIFTS TOWARD THE WEST-NORTHWEST AND IT CONTINUES TO INTENSIFY.
IN-FA'S MAXIMUM SUSTAINED WINDS ARE CURRENTLY AT 65 MPH, AND IT MAY
STRENGTHEN TO BECOME A CATEGORY 1 TYPHOON AS EARLY AS THIS EVENING.
BY MID-WEEK, IN-FA LOOKS TO STEADILY CONTINUE WEST-NORTHWEST AS IT
MOVES BETWEEN ENEWETAK IN THE NORTHERN RMI AND WAKE ISLAND FAR TO THE
NORTH, GENERALLY MOVING TOWARD THE FAR NORTHERN CNMI THROUGH THE END
OF THE WEEK.
FOR MORE INFORMATION ON TROPICAL STORM IN-FA, PLEASE REFER TO
BULLETINS FROM THE JOINT TYPHOON WARNING CENTER UNDER WMO HEADER
WTPN31 PGTW AND FROM THE NATIONAL WEATHER SERVICE UNDER WMO HEADER
WTPQ31 PGUM.
EASTERN MICRONESIA...
TROPICAL STORM IN-FA CONTINUES TO DOMINATE THE WEATHER PATTERN ACROSS
THE REGION, EVEN AS IT BEGINS TO EXIT THE NORTHERN MARSHALLS THIS
AFTERNOON. SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS PERSIST NEAR
POHNPEI, WITHIN THE CONVERGENT WESTERLY FLOW SOUTH OF THE STORM, BUT
DRIER RIDGING CONDITIONS PREVAIL FOR KOSRAE AND MAJURO, EVEN FARTHER
TO THE SOUTH AND SOUTHEAST. SHOWERS WILL GRADUALLY DIMINISH FOR
POHNPEI THROUGH TUESDAY, INCREASING ONCE MORE FOR POHNPEI AND KOSRAE
WEDNESDAY AND THURSDAY AS IN-FA SHIFTS WEST-NORTHWEST, AND SOUTHWEST
INFLOW STRENGTHENS SOUTH OF THE STORM AS IT BEGINS TO PASS NORTH OF
THE REGION. MAJURO CAN EXPECT A QUIET, DRIER PATTERN TO CONTINUE FOR
MUCH OF THE COMING WEEK.
A SPECIAL WEATHER STATEMENT REMAINS IN EFFECT, WITH THE LATEST
ISSUANCE THIS AFTERNOON HIGHLIGHTING ONGOING HAZARDS ACROSS THE
NORTHERNMOST ISLANDS AND ATOLLS OF THE MARSHALL ISLANDS, AS IN-FA
PULLS AWAY. HOWEVER, FAIRLY BENIGN MARINE CONDITIONS CONTINUE FOR THE
REST OF THE REGION, WITH COMBINED SEAS OF 4 TO 7 FEET, COMPRISED
MAINLY OF PRIMARY NORTH TO NORTHEAST SWELL AND SECONDARY SOUTHEAST
SWELL FOR POHNPEI AND KOSRAE, AND A PRIMARY WESTERLY SWELL AND
SECONDARY NORTHEAST SWELL FOR MAJURO. WEST TO SOUTHWEST SWELL LOOKS
TO DIMINISH FOR MAJURO OVER THE NEXT FEW DAYS AS THE NORTHEAST SWELL
BECOMES PRIMARY ONCE MORE. WINDS WILL REMAIN LIGHT TO MODERATE OUT OF
THE WEST TO SOUTHWEST ACROSS THE REGION THROUGH THE FORECAST PERIOD.
WESTERN MICRONESIA...
ONLY PATCHES OF SHOWERS BROUGHT ON BY A BROAD TROUGH, OVER EASTERN
YAP STATE, ARE SEEN ON SATELLITE THIS EVENING FOR MUCH OF WESTERN
MICRONESIA. FAIRLY BENIGN WEATHER IS IN STORE FOR MUCH OF THE REGION
WITH A FEW PERIODS OF SCATTERED SHOWERS FOR THE FORECAST PERIOD.
ANOTHER CONCERN IS FOR PALAU, THE SMOKE FROM THE INDONESIAN WILD
FIRES. THIS MAY CAUSE FOLK WITH RESPIRATORY ILLNESS TO HAVE A HARDER
TIME.
ALTIMETRY SHOWS COMBINED SEAS NEAR 6 FEET THROUGH OUT THE REGION.
THESE SEAS ARE EXPECTED TO GRADUALLY DECREASE THROUGH THURSDAY TO
AROUND 3 TO 5 FEET. WINDS ARE EXPECTED TO REMAIN LIGHT TO GENTLE.
GUM WATCHES/WARNINGS/ADVISORIES
GU...NONE.
MP...NONE.
MARIANAS WATERS...NONE.
MARIANAS/EAST AND WEST MICRONESIA/TROPICAL UPDATE: WHISNANT
MARIANAS: OGLE
EAST MICRONESIA/TROPICAL SYSTEMS: DECOU
WEST MICRONESIA: BOWSHER
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