244
FXPQ50 PGUM 070745
AFDGUM
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TIYAN GU
545 PM CHST WED JAN 7 2026
MARIANAS SYNOPSIS
LATEST SATELLITE DATA SHOWS MOSTLY CLOUDY SKIES ACROSS THE MARIANAS.
SCATTERED SHOWERS ARE SEEN OVER GUAM AND ROTA WITH ISOLATED SHOWERS
ACROSS TINIAN AND SAIPAN. ALTIMETRY SHOWS SEAS BETWEEN 7 AND 9 FEET.
DISCUSSION
THE SHEAR LINE HAS DRIFTED A LITTLE FARTHER SOUTH AS IT CONTINUES TO
WEAKEN. THIS FEATURE WILL CONTINUE TO PRODUCE MOSTLY CLOUDY SKIES
WITH SCATTERED SHOWERS ACROSS GUAM AND ROTA THROUGH TONIGHT, AND
ONLY ISOLATED SHOWERS FOR TINIAN AND SAIPAN. BY THURSDAY MORNING,
SHOWERS AND CLOUD COVER LOOK TO DECREASE, WITH A DRY TRADE-WIND
PATTERN MOVING BACK INTO THE MARIANAS. THE DRY PATTERN IS THEN
EXPECTED TO CONTINUE INTO NEXT WEEK. A BUILDING MID-LATITUDE HIGH
PRESSURE SYSTEM LOOKS TO BRING BREEZY CONDITIONS TO THE ISLANDS AT
THE END OF THE WEEK THROUGH THE MIDDLE OF NEXT WEEK.
MARINE/SURF
THE LONG PERIOD NORTH SWELL CONTINUES TO AFFECT THE REGION.
UNFORTUNATELY, THE RITIDIAN BUOY BROKE LOOSE FROM ITS MOORING EARLY
YESTERDAY MORNING, SO IT IS DIFFICULT TO DETERMINE THE SIZE OF THE
NORTH SWELL ACCURATELY. SURF OBSERVATIONS FROM TODAY SHOW SURF STILL
REACHING 9 TO 10 FEET ALONG NORTH FACING REEFS WHILE ALTIMETRY SHOWS
SEAS REMAIN IN THE 7 TO 9 FOOT RANGE BOTH EAST AND WEST OF THE
COASTAL WATERS. BASED ON THE AVAILABLE DATA, DECIDED TO EXTEND THE
HIGH SURF ADVISORY THROUGH TONIGHT FOR NORTH FACING REEFS AND THE
HIGH RIP CURRENT RISK STATEMENT THROUGH THURSDAY AFTERNOON, THOUGH
THE RIP RISK IS EXPECTED TO BECOME MODERATE BY THURSDAY MORNING ALONG
NORTH FACING REEFS, CONTINUING THROUGH THE AFTERNOON FOR EAST
FACING. SEAS ARE EXPECTED TO SLOWLY SUBSIDE THE NEXT COUPLE OF DAYS,
DROPPING TO BETWEEN 5 AND 7 FEET BY FRIDAY. HOWEVER, BY FRIDAY NIGHT,
SEAS LOOK TO QUICKLY BUILD AGAIN AS THE TRADE SWELL INCREASES DUE
STRONGER TRADE WINDS PRODUCED BY THE BUILDING MID-LATITUDE HIGH
PRESSURE SYSTEM. ALONG WITH THE INCREASED TRADE SWELL, ANOTHER ROUND
OF NORTHWEST TO NORTH SWELL LOOKS TO MOVE INTO THE WATERS. THIS IS
EXPECTED TO PUSH SEAS TO AROUND 10 FEET OVER THE WEEKEND. ALONG WITH
THE HIGHER SEAS, EXPECT SUSTAINED WINDS OF 22 KNOTS WITH NEAR-GALE
GUSTS AS EARLY AS FRIDAY NIGHT. THEREFORE, IT LOOKS LIKELY THAT A
SMALL CRAFT ADVISORY (SCA) WILL BE NEEDED FRIDAY NIGHT THROUGH THE
WEEKEND. ALONG WITH THE SCA, THE LIKELIHOOD OF STRONG RIP CURRENTS
WILL INCREASE TO HIGH ALONG EAST FACING REEFS, WITH A HIGH SURF
ADVISORY POSSIBLE ALONG WITH THE RIP CURRENTS FOR WEST AND NORTH
FACING REEFS. THE MARINE CONDITIONS WILL BE MONITORED CLOSELY OVER
THE NEXT COUPLE OF DAYS.
EASTERN MICRONESIA
FAIR WEATHER IS SEEN ACROSS MUCH OF THE REGION FROM THE RMI WESTWARD
TO POHNPEI. A SURFACE TROUGH STRETCHES NORTHWARD FROM BUTARITARI UP
TO WAKE ISLAND AND IS LARGELY DEVOID OF CONVECTION. HOWEVER, A MID-
TO UPPER-LEVEL LOW CENTERED NEAR 13N171E CONTINUES TO TRIGGER
THUNDERSTORMS WITH QUITE A BIT OF LIGHTNING. THUS FAR, THUNDERSTORMS
HAVE STAYED EAST OF THE ATOLLS AND ISLANDS OF THE RMI. WITH THAT
SAID, THE TROUGH AND UPPER LOW ARE BOTH DRIFTING WEST, AND WHILE
MODELS GENERALLY FAVOR DRY CONDITIONS, HAVE ADDED A SLIGHT CHANCE OF
THUNDERSTORMS FOR MAJURO THROUGH THURSDAY FOR THE PROXIMITY OF
DISTURBED WEATHER. FARTHER WEST, DRIER NNE WINDS WILL HOLD STEADY FOR
KOSRAE AND POHNPEI INTO THE WEEKEND WITH NO ORGANIZED FEATURES TO
WATCH FOR.
THINGS WILL BEGIN TO CHANGE OVER THE WEEKEND AS HIGH PRESSURE BUILDS
WELL TO THE NORTH. TYPICAL FOR THIS TIME OF YEAR, A TRADE-WIND SURGE
WILL RAMP UP FRI-SAT AND INTO EARLY NEXT WEEK. MODELS SHOW GUSTS
REACHING TO BETWEEN 25-30 MPH SUN-MON, ESPECIALLY FOR THE RMI FROM 8N
AND NORTHWARD. ALSO, OVER THE WEEKEND, THE INCREASED TRADES WILL
LEAD TO AN UPTICK IN SHOWERS AND THUNDERSTORMS IN KOSRAE AND POHNPEI
STATES AS TRADES CONVERGE INTO THE NORTHERN EDGE OF THE NEAR-
EQUATORIAL TROUGH.
LATEST BUOY AND ALTIMETRY DATA SHOW SEAS HAVE FALLEN BELOW 8 FT AFTER
PEAKING JUST ABOVE 8 FT NEAR POHNPEI EARLIER TODAY. THE HIGH SURF
ADVISORY FOR NORTH AND WEST REEFS OF POHNPEI REMAINS IN EFFECT BUT
SHOULD BE ABLE TO EXPIRE ON TIME OVERNIGHT WITH THE DOWNWARD TREND
CONTINUING. OVER THE NEXT COUPLE OF DAYS, SEAS WILL SETTLE DOWN
BETWEEN 4 AND 6 FT BEFORE INCREASING AGAIN FROM A MIX OF BOTH TRADE-
WIND SWELL AND LONG-PERIOD NORTHERLY SWELL. SEAS WILL APPROACH
SMALL CRAFT HAZARDOUS LEVELS OF 10 FT LATE IN THE WEEKEND OR AROUND
MONDAY. ADDITIONALLY, INCREASED WINDS OVER THE WEEKEND WILL LEAD TO
MUCH CHOPPIER SEA CONDITIONS IN THAT TIME FRAME.
WESTERN MICRONESIA
A DRY TRADE-WIND PATTERN EXTENDS ACROSS THE REGION, WITH THE REMAINS
OF A SHEAR LINE LINGERING TO THE NORTH OF YAP AND UPPER-LEVEL
TROUGHING PRODUCING A THIN LAYER OF CIRRUS OVER CHUUK. PALAU AND YAP
COULD STILL SEE SOME INCREASED CLOUD COVER THURSDAY NIGHT AND FRIDAY
FROM THE REMAINS OF THE SHEAR LINE AS IT DRIFTS SOUTHWEST, BUT THE
GFS AND ECMWF KEEP THE POTENTIAL FOR SHOWERS AROUND 20 PERCENT, WITH
A SLIGHTLY HIGHER POTENTIAL NORTHWEST AND THEN WEST OF THE ISLANDS.
CHUUK IS EXPECTED TO REMAIN FAIRLY DRY THROUGH FRIDAY.
THE UPCOMING TRADE-WIND SURGE WILL START TO DEVELOP FRIDAY, AND
CONTINUE THROUGH THE WEEKEND, AS HIGH PRESSURE BUILDS IN THE MID-
LATITUDES AND THE NEAR-EQUATORIAL TROUGH LIFTS SLIGHTLY NORTHWARD
FROM NEAR THE EQUATOR. BEST POTENTIAL FOR WINDS AND GUSTS AROUND
25-30 MPH IS CURRENTLY AROUND YAP PROPER AND OTHER ISLANDS NEAR AND
NORTH OF 8N, BUT THIS POTENTIAL COULD CHANGE, DEPENDING ON THE EXACT
LOCATION OF THE HIGH PRESSURE AND NEAR-EQUATORIAL TROUGH.
CONVERGENCE FROM THE INCREASED TRADES INTO THE NEAR-EQUATORIAL TROUGH
WILL INCREASE THE POTENTIAL FOR SHOWERS AND THUNDERSTORMS, FIRST
ACROSS CHUUK STATE AND THE OUTER ISLANDS OF YAP STATE FRIDAY NIGHT,
AND THEN INTO THE REPUBLIC OF PALAU THIS WEEKEND, BEFORE INCREASING
AT YAP PROPER BY MONDAY.
THE DRIFTING BUOY BETWEEN PALAU AND YAP HAS CONTINUED TO SHOW A
DOWNWARD TREND IN SEAS AND IS NOW REPORTING SEAS AROUND 5 FEET AS THE
PRIMARY SWELL DIRECTION IS BECOMING MORE NORTHEAST. ALTIMETRY DATA
SHOWS SEAS ARE MOSTLY AROUND 6 TO 7 FEET AT CHUUK AS THE NORTH-
NORTHWEST SWELL CONTINUES TO SLOWLY SUBSIDE. SEAS ARE EXPECTED TO
BECOME 4 TO 6 FEET THURSDAY INTO FRIDAY, DRIVEN BY THE PRIMARY
NORTHEAST TRADE SWELL AND LINGERING LONG-PERIOD NORTHERLY SWELL. THEN
FRIDAY NIGHT AND THROUGH THE WEEKEND, A TRADE-WIND SURGE WILL BUILD
THE NORTHEAST TO EAST SWELL AND POTENTIALLY BUILD SEAS TO HAZARDOUS
LEVELS OF 10 FEET FOR SMALL CRAFT THIS WEEKEND, ALONG WITH WINDS
NEARING THE 22 KT THRESHOLD, ESPECIALLY FOR ISLANDS NEAR AND NORTH OF
8N. EVEN IF SEAS AND WINDS DO NOT REACH THESE THRESHOLDS, CHOPPY SEA
CONDITIONS WILL OCCUR THIS WEEKEND AND POTENTIALLY INTO MONDAY. SURF
WILL ALSO BE ELEVATED ALONG NORTH AND EAST FACING REEFS DURING THIS
TIME AS WELL.
GUM WATCHES/WARNINGS/ADVISORIES
GU...HIGH RIP CURRENT RISK THROUGH THURSDAY AFTERNOON FOR GUZ001.
HIGH SURF ADVISORY UNTIL 4 AM CHST THURSDAY FOR GUZ001.
MP...HIGH RIP CURRENT RISK THROUGH THURSDAY AFTERNOON FOR MPZ001>003.
HIGH SURF ADVISORY UNTIL 4 AM CHST THURSDAY FOR MPZ001>003.
MARIANAS WATERS...NONE.
MARIANAS: KLEESCHULTE
EAST MICRONESIA: AYDLETT
WEST MICRONESIA: SCHANK
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