795
FXPQ50 PGUM 210836
AFDGUM
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TIYAN GU
636 PM CHST WED JAN 21 2026
MARIANAS SYNOPSIS
GENTLE TO MODERATE EASTERLIES PREVAIL ACROSS THE REGION. SATELLITE
IMAGERY AND DOPPLER RADAR INDICATE A LINE OF HEAVY THUNDERSTORMS
EXITING TO THE WEST. IPAN BUOY SHOWS 5 TO 6 FEET.
DISCUSSION
TROPICAL DISTURBANCE INVEST 92W CONTINUES TO BE THE PRIMARY WEATHER
CONCERN FOR THE MARIANAS THE NEXT SEVERAL DAYS, BEFORE A SHEARLINE
DESCENDS AND INTERACTS WITH THESE FEATURES TO FURTHER PRODUCE
UNSETTLED WEATHER COMING INTO EARLY NEXT WEEK. NUMEROUS HEAVY SHOWERS
ARE EXPECTED TO CONTINUE THROUGH AT LEAST THURSDAY NIGHT, WITH A
SHORT LULL IN SHOWERS AFTER MIDNIGHT TONIGHT BEFORE SHOWERS PICKUP
ONCE AGAIN POTENTIALLY RIGHT AROUND SUNRISE, AS 92W COMES CLOSER TO
THE MARIANAS. STRONG TO NEAR-GALE FORCE GUSTS ARE EXPECTED NEAR THE
MOST INTENSE SHOWERS, ESPECIALLY NEAR GUAM AND ROTA THROUGH THURSDAY
AFTERNOON. AFTER, 92W WILL CONTINUE TO MOVE WEST AND INTERACT WITH A
DESCENDING SHEARLINE, WHICH WILL PROVIDE THE MARIANAS WITH A SHORT
BREAK IN SHOWERS FOR MUCH OF FRIDAY; ONCE THE SHEARLINE FINALLY
DESCENDS ACROSS THE REGION, GENTLE SOUTHERLY WINDS WILL QUICKLY SHIFT
TO THE NORTHEAST AND POTENTIALLY BECOME FRESH TO STRONG, WITH SHOWERS
BECOMING MORE LIKELY. HIGH UNCERTAINTY REMAINS AT THIS TIME REGARDING
THE SHEARLINE EVENT THIS WEEKEND, DUE TO COMPLEX INTERACTIONS
EXPECTED BETWEEN THE RETROGRADING REMNANTS OF NOKAEN (01W), 92W AND
THE SHEARLINE OVER THE NEXT SEVERAL DAYS.
MARINE
A MODERATE RISK OF RIP CURRENTS IS EXPECTED ALONG NORTH AND EAST
FACING REEFS OF THE MARIANAS FOR AT LEAST THE NEXT SEVERAL DAYS.
AS A SIGNIFICANT NORTHERLY PULSE PRODUCED BY DISTANT SYNOPTIC
FEATURES AND A DESCENDING SHEARLINE MAKE THEIR WAY ACROSS THE REGION,
HAZARDOUS SURF AND A HIGH RIP CURRENT RISK MAY DEVELOP ALONG NORTH
FACING REEFS OF THE MARIANAS AS EARLY AS LATE THIS WEEKEND. THIS WILL
ALLOW 5 TO 6 FOOT SEAS TO RISE BEGINNING FRIDAY, POTENTIALLY
BECOMING HAZARDOUS TO SMALL CRAFT BY EARLY NEXT WEEK.
TROPICAL SYSTEMS
A LARGELY DISORGANIZED TROPICAL DISTURBANCE, KNOWN AS JTWC'S INVEST
92W, IS CENTERED NEAR 8N145E IN EASTERN YAP STATE. THIS FEATURE
CONTINUES TO HAVE A MOSTLY CLEAR CENTER OF ROTATION, AS IT CONTINUES
ITS SLOW TREK TO THE NORTHWEST. THIS SYSTEM IS EXPECTED TO REMAIN IN
ITS CURRENT STATE UNTIL IT STALLS JUST NORTHEAST OF YAP AND WEST-
SOUTHWEST OF THE MARIANAS, INTERACTING WITH THE AFOREMENTIONED
REMNANTS OF NOKAEN (01W) AND A DESCENDING SHEARLINE BEFORE BECOMING
PART OF THE MASSIVE FRONTAL SYSTEM BY THE WEEKEND.
EASTERN MICRONESIA
A WEAK FRAGMENT OF THE INTERTROPICAL CONVERGENCE ZONE (ITCZ) EXTENDS
INTO THE REGION AT AROUND 5N180, INTERACTING WITH A TRADE-WIND TROUGH
SOUTHEAST OF MAJURO. HIMAWARI VISIBLE SATELLITE THIS AFTERNOON SHOWS
SCATTERED TO NUMEROUS SHOWERS THERE, EXTENDING OVER A PORTION OF THE
SOUTHERN RMI INCLUDING MILI AND BUTARITARI. ALTHOUGH MOST OF THE
SHOWERS WILL STAY SOUTH OF MAJURO, ISOLATED COVERAGE IS EXPECTED TO
BECOME SCATTERED TONIGHT OVER MAJURO COASTAL WATERS AS THE TRADE-
WIND TROUGH MOVES WEST AND CROSSES THE SOUTHERN MARSHALLS. FURTHER
WEST, SCATTERED SHOWERS NEAR POHNPEI ARE EXPECTED TO DIMINISH
OVERNIGHT AS THE WEAK TRADE-WIND CONVERGENCE ALONG THE BACKSIDE OF
INVEST 92W MOVES SLIGHTLY FURTHER AWAY. SHOWERS WILL INCREASE FOR
KOSRAE AROUND THURSDAY NIGHT INTO THE END OF THE WEEK AS THE REMNANTS
OF THE ITCZ FRAGMENT SOUTHEAST OF MAJURO MOVE WEST INTO THE AREA.
OTHERWISE, A FAIRLY DRY TRADE-WIND REGIME LOOKS TO DOMINATE OVER THE
NEXT WEEK OR SO.
WINDS WILL REMAIN MOSTLY LIGHT TO MODERATE ACROSS THE REGION,
BECOMING FRESH AT TIMES FOR MAJURO TONIGHT ALONG THE EDGE OF A
SLIGHT TRADE SURGE. BUOY AND ALTIMETRY DATA SHOW COMBINED SEAS OF 4
TO 6 FEET NEAR POHNPEI AND KOSRAE, AND 7 TO 8 FEET NEAR MAJURO,
PEAKING JUST OVER 9 FEET FURTHER NORTH. SEAS ARE COMPRISED OF THE
BACKGROUND TRADE SWELL AND A SECONDARY NORTH SWELL, WHICH LOOKS TO
PERSIST THROUGHOUT THE FORECAST PERIOD FOR KOSRAE AND POHNPEI AND
DIMINISH THIS WEEKEND NEAR MAJURO, BEFORE A STRONG PULSE OF NORTH TO
NORTHWEST SWELL LOOKS TO MOVE IN EARLY NEXT WEEK.
WESTERN MICRONESIA
A BROAD, POORLY ORGANIZED TROPICAL DISTURBANCE, INVEST 92W, IS
CENTERED NEAR 8N145E. CONVECTION IS LIMITED WITH 92W, WITH ONLY
SPOTTY SHOWERS FOUND WITH THE SYSTEM WEST OF CHUUK. SCATTERED
SHOWERS AND ISOLATED THUNDERSTORMS ARE SEEN OVER WENO.
FOR CHUUK, SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS WILL
CONTINUE THROUGH TONIGHT. BY THURSDAY MORNING, A BRIEF DRY PATTERN
WILL MOVE INTO THE REGION, WITH CHUUK SEEING SCATTERED SHOWERS AND
ISOLATED THUNDERSTORMS AGAIN THURSDAY NIGHT INTO FRIDAY AS 92W MOVES
NORTHWEST, BRINGING A BAND OF INCREASED CONVERGENCE TO THE STATE. BY
FRIDAY NIGHT AND EXTENDING THROUGH THE BEGINNING OF NEXT WEEK, A DRY
TRADE-WIND PATTERN IS EXPECTED TO PREVAIL. GENTLE TO MODERATE TRADE
WINDS WILL CONTINUE THROUGH THE WEEKEND AND INTO NEXT WEEK. SEAS ARE
EXPECTED TO REMAIN AROUND 4 TO 6 FEET THROUGH NEXT MONDAY.
FOR YAP AND PALAU, ONLY ISOLATED SHOWERS ARE EXPECTED THROUGH THE
END OF THE WEEK INTO THE WEEKEND, THOUGH YAP DOES HAVE A RISK OF
THUNDERSTORMS TONIGHT. BY SUNDAY, INCREASED CONVECTION IS EXPECTED
AS 92W MOVES WELL NORTHWEST OF YAP PROPER AND BEGINS TO BECOME BETTER
ORGANIZED. THIS IS EXPECTED TO PUT A WEAK FEEDER BAND OVER YAP AND
PALAU. LIGHT TO GENTLE WINDS ARE EXPECTED AT YAP THROUGH THE
WEEKEND. GENTLE TO MODERATE TRADE WINDS WILL BECOME LIGHT TO GENTLE
THURSDAY, CONTINUING THROUGH THE WEEKEND. SEAS WILL BEGIN TO BUILD
THURSDAY AT BOTH LOCATIONS, WITH SEAS UP TO 10 FEET POSSIBLE OVER THE
WEEKEND INTO NEXT WEEK, PRODUCED BY DISTANT SYNOPTIC SYSTEMS IN THE
MID-LATITUDES. IF THIS DOES OCCUR, A SMALL CRAFT ADVISORY ALONG WITH
A HIGH SURF ADVISORY FOR NORTH FACING REEFS MAY BE NEEDED.
GUM WATCHES/WARNINGS/ADVISORIES
GU...NONE.
MP...NONE.
MARIANAS WATERS...NONE.
MARIANAS/TROPICAL: MONTVILA
EASTERN MICRONESIA: DECOU
WESTERN MICRONESIA: KLEESCHULTE
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