231
FXPQ50 PGUM 270745
AFDGUM
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TIYAN GU
545 PM CHST SAT DEC 27 2025
MARIANAS SYNOPSIS
MOSTLY CLOUDY SKIES WITH SCATTERED SHOWERS ARE MOVING ACROSS THE
REGION THIS EVENING, BUT THESE CLOUDS AND SHOWERS WILL DECREASE IN
COVERAGE THE NEXT FEW HOURS BASED ON SATELLITE ANALYSIS. SEAS REMAIN
IN THE 5 TO 7 FOOT RANGE, WITH A WATER TEMPERATURE OF 84 DEGREES.
DISCUSSION
SCATTERED SHOWERS DEVELOPED AND MOVED ACROSS THE MARIANAS THIS
AFTERNOON, BUT CONDITIONS WILL IMPROVE THE NEXT FEW HOURS. OTHERWISE,
LOOKING AHEAD THROUGH TONIGHT AND THE NEXT SEVERAL DAYS, LOOK FOR
PLEASANT CONDITIONS TO CONTINUE WITH JUST A QUICK HIT-AND-MISS
SHOWER CROSSING THE REGION FROM TIME TO TIME.
MARINE
SEAS OF 5 TO 7 FEET MAY INCREASE A FOOT OR SO DURING THE FIRST HALF
OF NEXT WEEK, AS A NORTHERLY SWELL TRIES TO PUSH INTO THE REGION. THE
GFS MODEL IS MORE AGGRESSIVE WITH THIS AS IT PUSHES A SHEAR LINE
DOWN TO BETWEEN PAGAN AND SAIPAN, ALLOWING THE NORTH SWELL TO MOVE IN
WITH THE MODEL ALSO SHOWING SLIGHTLY HIGHER WINDS BEHIND THE SHEAR
LINE. CONVERSELY, THE ECMWF KEEPS THE SHEAR LINE FURTHER NORTH WITH
WEAKER WINDS, MAKING HOW FAR SOUTH WILL THE NORTHERLY SWELL MAKE IT
BEFORE BECOMING ABSORBED INTO THE TRADE SWELL A QUESTION THAT REMAINS
TO BE SEEN/ANSWERED. OTHERWISE, GENTLE TO MODERATE WINDS WILL
PREVAIL.
EASTERN MICRONESIA
LATEST SATELLITE IMAGERY SHOWS PARTLY CLOUDY SKIES WITH ISOLATED
SHOWERS ACROSS EASTERN MICRONESIA THIS AFTERNOON. A COUPLE OF
THUNDERSTORMS ARE SEEN TO THE EAST-SOUTHEAST OF KOSRAE. ALTIMETRY
DATA SHOWS SEAS BETWEEN 5 AND 8 FEET FOR KOSRAE AND MAJURO AND 7 TO
9 FEET FOR POHNPEI. ALTHOUGH, POHNPEI BUOY MEASURED A PEAK IN SEA
HEIGHTS, REACHING 10.2 FEET EARLIER THIS AFTERNOON.
AN OVERALL DRY TRADE-WIND PATTERN REMAINS ANCHORED ACROSS THE
REGION. THIS DRY PATTERN LOOKS TO CONTINUE FOR POHNPEI AND MAJURO
THROUGH MOST OF NEXT WEEK. KOSRAE IS ALSO EXPECTED TO REMAIN DRY
THROUGH MONDAY NIGHT. BY TUESDAY, A WEAK BAND OF CONVERGENCE,
POSSIBLY A WEAK INTER-TROPICAL CONVERGENCE ZONE (ITCZ) IS EXPECTED
TO DEVELOP, REMAINING SOUTH OF POHNPEI AND MAJURO. THIS IS EXPECTED
TO RESULT IN AN INCREASE IN CONVECTION FOR A COUPLE OF DAYS OVER
KOSRAE. POPS (PROBABILITY OF PRECIPITATION) ARE EXPECTED TO REMAIN
AROUND 30%. BY THE END OF THE WEEK, KOSRAE CAN EXPECT DRY CONDITIONS
TO RETURN.
FOR THE MARINE FORECAST, THERE WERE A COUPLE OF CHANGES MADE TO THE
POHNPEI FORECAST. THE SMALL CRAFT ADVISORY (SCA) WAS INITIALLY
ALLOWED TO EXPIRE AS SEAS WERE HOVERING AROUND 9 FEET. HOWEVER,
AFTER THE SCA EXPIRED, POHNPEI BUOY SHOWED SEAS INCREASED TO 10.2
FEET. THEREFORE, A NEW SCA WAS ISSUED AND THE FORECAST WAS UPDATED.
THE SEAS ARE EXPECTED TO SUBSIDE THROUGH THE NIGHT, WITH SEAS FALLING
BELOW 10 FEET BY SUNDAY MORNING. THE LARGE, LONG-PERIOD NORTH SWELL
CONTINUES TO AFFECT POHNPEI AND LOOKS TO REMAIN HIGH ENOUGH TO
MAINTAIN HAZARDOUS SURF ALONG NORTH FACING REEFS THROUGH SUNDAY
AFTERNOON, RESULTING IN THE HIGH SURF ADVISORY (HSA) BEING EXTENDED
THROUGH 3 PM SUNDAY. FOR KOSRAE, THE HSA CONTINUES THROUGH TONIGHT
FOR NORTH FACING REEFS. AS THE NORTH SWELL SUBSIDES OVERNIGHT AND THE
TRADE SWELL BUILDS, SURF IS EXPECTED TO BECOME HAZARDOUS ALONG EAST
FACING REEFS SUNDAY MORNING WHILE FALLING BELOW HAZARDOUS LEVELS
ALONG NORTH FACING REEFS. NO MAJOR CHANGES TO THE MAJURO FORECAST.
WESTERN MICRONESIA
DAYTIME SCATTEROMETRY DATA CAPTURED WINDS CONVERGING ALONG A BROAD
TRADE-WIND DISTURBANCE, GENERATING DEEP CONVECTION AND WIDESPREAD
CLOUDINESS ACROSS SOUTHERN CHUUK STATE AND SOUTHEASTERN YAP STATE.
SATELLITE AND MODEL TRENDS INDICATE THIS FEATURE IS WEAKENING WITH
SOME HEAVIER CONVECTION COLLAPSING EARLIER THIS AFTERNOON, SENDING
AN OUTFLOW BOUNDARY NORTHWARD TOWARDS CHUUK LAGOON. HOWEVER,
TRACKING THIS ON VISIBLE SATELLITE REVEALED IT ONLY MOVING AROUND 15
KT. OVERALL, AN UNORGANIZED TRADE-WIND PATTERN PERSISTS THE NEXT
SEVERAL DAYS, WITH A BROAD TROUGH SETTING UP WEST OF PALAU OVER THE
NEXT FEW DAYS, ALSO INTERACTING WITH A SHEAR LINE DRAPED TO NORTH,
NEAR 15N. VARIOUS TRADE-WIND TROUGHS AND POCKETS OF TRADE-WIND
CONVERGENCE BEHIND THIS PATTERN WILL STILL BRING PERIODIC UPTICKS IN
SHOWERS TO THE REGION. HOWEVER, THIS STILL LOOKS TO BE MAINLY FOR
PALAU, SINCE LATEST MODEL GUIDANCE SHOWS THE BULK OF CONVECTION
REMAINING MOSTLY SOUTH OF YAP AND CHUUK.
ALTIMETRY DATA SHOWS 5 TO 7 FEET NEAR PALAU, 6 TO 8 FEET NEAR YAP,
AND 7 TO 9 FEET NEAR CHUUK. LONG-PERIOD NORTH TO NORTHEAST SWELL
EMANATING FROM STRONG MID-LATITUDE SYNOPTIC SYSTEMS CONTINUES TO
ELEVATE SURF ALONG NORTH AND EAST FACING REEFS AND CHUUK, WITH
A HIGH SURF ADVISORY STILL IN EFFECT FOR NORTH-FACING REEFS OF CHUUK
THROUGH AT LEAST SUNDAY AFTERNOON. FOR YAP AND PALAU, A NOTABLE
PULSE OF NORTH TO NORTHWEST SWELL LOOKS TO ARRIVE SUNDAY AFTERNOON
THROUGH MONDAY. THIS, COMBINED WITH THE CURRENT NORTHEAST SWELL, IS
EXPECTED TO INCREASE CONCERN FOR HAZARDOUS SURF ALONG NORTH-FACING
REEFS. WENT AHEAD AND ISSUED A HIGH SURF ADVISORY FOR YAP STARTING
SUNDAY AFTERNOON, BUT WILL CONTINUE TO MONITOR AND REASSESS THIS FOR
PALAU OVER THE NEXT 24 HOURS. AFTER THIS PULSE OF NORTHERLY SWELL
MOVES THROUGH, COMBINED SEAS LOOK TO MOMENTARILY DECREASE TO 5 TO 7
FEET TUESDAY AND WEDNESDAY, THEN ANOTHER PULSE OF LONG-PERIOD
NORTHEASTERLY SWELL MAY BOOST SEAS AND SURF AT CHUUK LATE NEXT WEEK.
LIGHT TO MODERATE WINDS PERSIST AT YAP AND PALAU OVER THE NEXT
SEVERAL DAYS. GENTLE TO MODERATE TRADES NEAR CHUUK ARE EXPECTED TO
INCREASE TO MODERATE TO FRESH STARTING AROUND THE MIDDLE OF NEXT
WEEK.
GUM WATCHES/WARNINGS/ADVISORIES
GU...NONE.
MP...NONE.
MARIANAS WATERS...NONE.
MARIANAS: DOLL
EAST MICRONESIA: KLEESCHULTE
WEST MICRONESIA: CRUZ
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