247
FXPQ50 PGUM 110918
AFDGUM
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TIYAN GU
718 PM CHST SUN JAN 11 2026
MARIANAS SYNOPSIS
THERE IS A HIGH SURF ADVISORY (HSA), AND HIGH RISK OF RIP CURRENTS
STATEMENT THAT REMAINS IN EFFECT.
SATELLITE IMAGERY SHOWS PARTLY CLOUDY SKIES, WHILE RADAR IMAGERY
SHOWS A FEW ISOLATED SHOWERS MOVING ACROSS GUAM'S SOUTHERN WATERS.
ALTIMETRY SHOWS COMBINED SEAS OF 6 TO 8 FEET AROUND THE ISLANDS.
IPAN BUOY DATA SHOWS HEIGHTS OF ABOUT 6 FEET AND ABOUT 8 SECOND
PERIODS.
DISCUSSION
THE CIMSS MIMIC, A SATELLITE DERIVED PRODUCT, SHOWS A FAIRLY DRY
ATMOSPHERE ACROSS THE REGION. PRECIPITABLE WATER (PWATS) RANGE
BETWEEN 1.4 AND 1.7 INCHES OF AVAILABLE MOISTURE FOR CLOUDS AND
SHOWERS GENESIS. A FEW SHOWERS ARE TRYING TO DEVELOP WITHIN THE
TRADE SURGE, HOWEVER, TIME-HEIGHTS STILL SHOW A RATHER LARGE POCKET
OF DRY AIR IN THE UPPER EXTENT OF THE LOWER LAYERS AND ABOVE. THIS
POCKET WILL BE MORE DIFFICULT FOR SUSTAINED SHOWERS TO DEVELOP. OVER
THE NEXT FEW DAYS, SHOWERS ARE EXPECTED TO BE A LITTLE EASIER TO
DEVELOP AS A FEW MOISTURE POCKETS ARE EXPECTED TO MOVE IN MONDAY AND
TUESDAY. OTHERWISE, A DRY TRADE-WIND PATTERN IS EXPECTED THROUGH THE
REST OF THE WEEK.
MARINE/SURF
THE WINDS AND SEAS HAVE WEAKENED A BIT SINCE YESTERDAY. WINDS AND
SEAS HAVE FALLEN BELOW 22 KNOTS AND 10 FEET THRESHOLDS. THIS
WEAKENING HAS ALLOWED THE SMALL CRAFT ADVISORY (SCA) TO EXPIRE.
MODERATE TO FRESH EAST WINDS WILL CONTINUE THROUGH THE WEEK. SEAS ARE
EXPECTED TO HOVER AROUND THE RANGE OF 7 TO 9 FEET THROUGH THE FIRST
HALF OF THE WEEK. THE TRADE SWELL IS EXPECTED TO BE 6 TO 7 FEET THIS
WEEK WITH A PERIOD OF 8 TO 11 SECONDS. THEN AROUND MIDWEEK, THE NORTH
SWELL IS ANTICIPATED TO BUILD TO AROUND 5 FEET, AND SEAS ARE
EXPECTED TO RISE TO AROUND 10 FEET, AND WILL GRADUALLY FALL FOR THE
WEEKEND.
OVERALL, THE SURF IS EXPECTED TO AVERAGE OUT TO AROUND 8 TO 10 FEET
ALONG NORTH AND EAST FACING REEFS FOR THE LATTER HALF OF THE WEEK.
SLIGHT CHANGES IN SWELL MAY ALLOW THE SURF TO PERIODICALLY DROP
SLIGHTLY BELOW THRESHOLDS FOR HIGH SURF AND HIGH RISK OF RIP
CURRENTS.
EASTERN MICRONESIA
LATEST SATELLITE DATA SHOWS CLOUDY SKIES WITH NUMEROUS SHOWERS AND
ISOLATED THUNDERSTORMS OVER POHNPEI, MOSTLY CLOUDY SKIES AND
SCATTERED SHOWERS OVER KOSRAE AND PARTLY CLOUDY SKIES WITH ISOLATED
SHOWERS OVER MAJURO. POHNPEI BUOY SHOWS SEAS FLUCTUATING BETWEEN 7
AND 9 FEET WITH A NORTHEAST SWELL OF 5 TO 7 FEET. ALTIMETRY SHOWS
SEAS OF 7 TO 9 FEET FOR POHNPEI AND 5 TO 7 FEET FOR KOSRAE AND
MAJURO.
A BAND OF CONVERGENCE HAS FORMED TO THE NORTHEAST OF A WEAK, BROAD
CIRCULATION FOUND ALONG THE NEAR-EQUATORIAL TROUGH (NET). THIS BAND
OF CONVERGENCE LOOKS TO BE THE AREA THAT THE MODELS LIKE THE
DEVELOPMENT OF AN INTER-TROPICAL CONVERGENCE ZONE (ITCZ). THERE IS
ALREADY A SOUTHEAST FLOW INTO THIS AREA CONVERGING WITH THE
NORTHEAST TO EAST TRADES. AS THIS FEATURE CONTINUES TO DEVELOP,
EXPECT CONVECTION TO CONTINUE ACROSS POHNPEI AND KOSRAE. NUMEROUS
SHOWERS AND ISOLATED THUNDERSTORMS WILL CONTINUE ACROSS POHNPEI
THROUGH TONIGHT, WITH CONVECTION EXPECTED TO INCREASE AT KOSRAE TO
NUMEROUS SHOWERS BY MONDAY MORNING. THERE ARE A COUPLE OF WEAK
TRADE-WIND TROUGHS TO THE EAST-NORTHEAST OF THE CONVERGENCE THAT WILL
APPROACH THE DEVELOPING ITCZ, STRENGTHENING CONVERGENCE AND
MAINTAINING CONVECTION ACROSS BOTH POHNPEI AND KOSRAE. BOTH LOCATIONS
CAN EXPECT TO SEE BRIEF PERIODS WITH POPS (PROBABILITY OF
PRECIPITATION) AT AROUND 20%, THOUGH OVERALL, AN UNSETTLED PATTERN IS
EXPECTED THROUGH THE WEEK.
FOR MAJURO, THE DRY PATTERN TONIGHT LOOKS TO CHANGE BY MONDAY
MORNING. A TRADE-WIND TROUGH LOOKS TO MOVE INTO THE MARSHALLS FROM
NEAR THE DATE LINE. ALONG WITH THIS TROUGH, A BAND OF CONVERGENCE IS
EVIDENT EAST OF 175E. THESE FEATURES LOOK TO LINK UP AND BRING A MORE
UNSETTLED PATTERN TO THE ATOLL BY MONDAY MORNING. BY TUESDAY, THE
TROUGH WILL BE WEST OF THE MARSHALLS AND THE CONVERGENCE BAND IS
EXPECTED TO DROP FARTHER SOUTH, ALLOWING A PERIOD OF DRIER WEATHER
OVER THE MARSHALLS. BY MIDWEEK, THIS BAND OF CONVERGENCE LOOKS TO
LINK WITH THE BAND AFFECTING POHNPEI AND KOSRAE AND DRIFT NORTH, WITH
ADDITIONAL TRADE-WIND TROUGHS MOVING INTO THE REGION. THIS WILL
MAINTAIN AN UNSETTLED PATTERN OVER THE MARSHALL ISLANDS THROUGH THE
END OF THE WEEK.
OVERALL, MARINE CONDITIONS LOOK TO BE ON TRACK FOR ROUGH CONDITIONS
THROUGH THE WEEK. LATEST WAVE MODEL DATA SHOWS SEAS AROUND 1 TO 2
FEET LOWER THAN SEEN ON ALTIMETRY AND POHNPEI BUOY. SEAS ARE
FLUCTUATING BETWEEN 7 AND 9 FEET AT POHNPEI, WITH A PRIMARY
NORTHEAST SWELL OF AROUND 5 TO 7 FEET. THIS WILL MAINTAIN SURF ALONG
NORTH FACING REEFS BETWEEN 7 AND 9 FEET THROUGH TONIGHT AND INTO
MONDAY AFTERNOON. SEAS WILL THEN SUBSIDE A BIT. AROUND TUESDAY, SEAS
WILL BEGIN TO BUILD AGAIN ACROSS THE REGION AS A TRADE-WIND SURGE
PRODUCES FRESH TO STRONG WINDS WITH NEAR-GALE GUSTS ACROSS THE
REGION, BEGINNING AS EARLY AS TUESDAY AT MAJURO, TUESDAY NIGHT AT
KOSRAE AND WEDNESDAY AT POHNPEI. ALONG WITH THE WINDS, THE SURGE WILL
PRODUCE COMBINED SEAS AS HIGH AS 10 FEET FOR POHNPEI AND KOSRAE AND
UP TO 12 FEET FOR MAJURO. ALL LOCATIONS WILL BE MONITORED CLOSELY TO
DETERMINE WHEN A A SMALL CRAFT ADVISORY BECOMES NECESSARY FOR EACH
LOCATION.
WESTERN MICRONESIA
A BROAD, WEAK CIRCULATION IS FOUND SOUTH OF EAURIPIK IN EASTERN YAP
STATE AND IS EMBEDDED WITHIN THE NEAR-EQUATORIAL TROUGH (NET) NEAR
3N143E. IT IS EXPECTED TO MOVE WEST-NORTHWESTWARD, GRADUALLY
BECOMING BETTER ORGANIZED AS IT PASSES SOUTH OF YAP AND PALAU OVER
THE NEXT FEW DAYS. CONVERGENCE NORTH OF THE DISTURBANCE IS EXPECTED
TO INCREASE SIGNIFICANTLY OVER YAP AND PALAU, WITH NUMEROUS TO
WIDESPREAD, LOCALLY HEAVY SHOWERS AND ISOLATED THUNDERSTORMS STARTING
TO BUILD IN FROM THE SOUTHEAST BY MONDAY EVENING. WITH THIS,
NORTHEAST WINDS OF 15 TO 25 KT AND GUSTS TO 30 KT REMAIN POSSIBLE
WITH SHOWERS, THEN BECOME EAST TO SOUTHEAST AROUND MIDWEEK AS THE
CIRCULATION PASSES SOUTHWEST OF KOROR. AS THE DISTURBANCE MOVES
WEST AND NORTHWEST OF PALAU IN THE LATTER HALF OF THE WEEK, TRAILING
SHOWERS WITHIN THE SOUTH-SOUTHWESTERLY FLOW MAY CONTINUE TO IMPACT
PALAU, AND TO A LESSER EXTENT, YAP, THROUGH LATE WEEK. A FAIR AMOUNT
OF UNCERTAINTY STILL EXISTS AS THIS IS A FEW DAYS OUT, BUT FURTHER
UPDATES WILL BE PROVIDED AS WE MONITOR TRENDS IN SATELLITE
OBSERVATIONS AND MODEL GUIDANCE. REFER TO THE SPECIAL WEATHER
STATEMENT FOR MORE INFORMATION, INCLUDING ANY UPDATES ON THIS
EVOLVING SITUATION.
THE DISTURBANCE IS CURRENTLY SOUTHWEST OF CHUUK, ALTHOUGH NUMEROUS
SHOWERS AND ISOLATED THUNDERSTORMS ARE EXPECTED TO BUILD IN TONIGHT
THROUGH MONDAY AS CONVERGENCE NORTH AND EAST INCREASES AROUND THE
DISTURBANCE. SHOWER COVERAGE LOOKS TO TREND DOWN TO SCATTERED AROUND
MIDWEEK AS THE DISTURBANCE MOVES FARTHER AWAY TO WEST.
A DRIFTING BUOY NORTHEAST OF PALAU SHOWS SEAS HAVE DROPPED TO AROUND
9 FEET, HOWEVER, FREQUENT GUSTS TO 25 KT WILL CONTINUE TO PRODUCE
HAZARDOUS CONDITIONS FOR SMALL CRAFT OPERATIONS THROUGH TONIGHT.
ADDITIONALLY, SEAS AND WINDS MAY INCREASE BACK UP TO HAZARDOUS LEVELS
BY MONDAY AFTERNOON OR EVENING, SO EXTENDED THE SMALL CRAFT
ADVISORY FOR PALAU TUESDAY AFTERNOON. SIMILARLY, EXTENDED YAP'S
SMALL CRAFT ADVISORY FROM EARLY MONDAY MORNING TO TUESDAY AFTERNOON.
EXTENDED THE HIGH SURF ADVISORY FOR NORTH-FACING REEFS THROUGH
TUESDAY AFTERNOON AS WELL, BUT DROPPED IT FOR EAST-FACING REEFS
BECAUSE SURF IS EXPECTED TO BE 8 TO 11 FEET, JUST BELOW HAZARDOUS
LEVELS OF 12 FEET FOR EAST-FACING REEFS.
GUM WATCHES/WARNINGS/ADVISORIES
GU...HIGH RIP CURRENT RISK THROUGH TUESDAY AFTERNOON FOR GUZ001.
HIGH SURF ADVISORY UNTIL 4 PM CHST TUESDAY FOR GUZ001.
MP...HIGH RIP CURRENT RISK THROUGH TUESDAY AFTERNOON FOR MPZ001>003.
HIGH SURF ADVISORY UNTIL 4 PM CHST TUESDAY FOR MPZ001>003.
MARIANAS: BOWSHER
EAST MICRONESIA: KLEESCHULTE
WEST MICRONESIA: CRUZ
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