289
FXPQ50 PGUM 170825
AFDGUM
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TIYAN GU
625 PM CHST TUE FEB 17 2026
MARIANAS SYNOPSIS
ISOLATED TO LOW-END SCATTERED SHOWERS WILL BE POSSIBLE WHILE WINDS
AND SEAS CONTINUE TO DIMINISH THROUGH MIDWEEK. A SHEAR LINE WILL
MOVE TOWARD THE MARIANAS AND BRING INCREASING SHOWER AND ISOLATED
THUNDERSTORM CHANCES, BREEZY WINDS, AND POTENTIALLY HAZARDOUS SEAS
LATE THIS WEEKEND INTO EARLY NEXT WEEK.
DISCUSSION
AFTERNOON SATELLITE IMAGERY SHOWS PARTLY TO MOSTLY CLOUDY SKIES
ACROSS THE MARIANAS AND ISOLATED TO LOW-END SCATTERED SHOWERS IN THE
VICINITY OF GUAM AND ROTA. FRAGMENTS OF A SHEAR LINE ARE LOCATED TO
THE SOUTH AND EAST OF GUAM AND THESE FEATURES WILL CONTINUE TO BE
CARRIED BY THE EASTERLY TRADES IN THE COMING DAYS. ISOLATED TO BRIEF
PERIODS OF SCATTERED SHOWERS WILL CONTINUE TO BE POSSIBLE THROUGH
MIDWEEK AND GIVEN THE DRIER AIR MOVING INTO THE REGION, NO FLOODING
CONCERNS ARE ANTICIPATED. ANOTHER SHEAR LINE IS EXPECTED TO DESCEND
SOUTHWARD TOWARD THE MARIANAS THIS WEEKEND. BREEZY AND SHOWERY
WEATHER ARE POSSIBLE WITH THIS FEATURE. AN INCREASE OF MOISTURE
ASSOCIATED WITH THE SHEAR LINE MAY LEAD TO ISOLATED THUNDERSTORMS
STARTING SUNDAY FOR THE CNMI AND INTO NEXT WEEK FOR GUAM AS THE SHEAR
LINES DESCENDS SOUTHWARD.
MARINE
AN ALTIMETRY PASS FROM THIS MORNING SHOWED SEAS AROUND GUAM FROM 6
TO 8 FEET WITH THE IPAN BUOY CONTINUING TO SHOW A DOWNWARD TREND IN
SEAS AND SWELL THIS AFTERNOON. AS A RESULT, HAVE LET THE HIGH RIP
CURRENT RISK FOR EAST FACING REEFS EXPIRE AS SCHEDULED. WINDS AND
SEAS ARE EXPECTED TO CONTINUE TO DIMINISH THROUGH AT LEAST THURSDAY
WITH SEAS FALLING AS LOW AS 4 TO 6 FEET. A NORTHERLY SWELL ASSOCIATED
WITH A DECAYING FRONT INTO A SHEAR LINE NORTH OF THE REGION WILL
MOVE THROUGH THE WATERS ON FRIDAY AND SEAS WILL BUILD A COUPLE OF
FEET IN RESPONSE. THIS SHEAR LINE IS FORECAST TO MOVE SOUTHWARD
TOWARD THE MARIANAS THIS WEEKEND, BRINGING FRESH, POSSIBLY STRONG,
WINDS FROM NORTH TO SOUTH AS THIS FEATURE DESCENDS SOUTHWARD.
POTENTIALLY HAZARDOUS SEAS OF AROUND 10 FEET WILL BE POSSIBLE LATE
THIS WEEKEND AND INTO EARLY NEXT WEEK.
EASTERN MICRONESIA
TODAY'S MODEL RUNS HAVE BACKED OFF THE NORTHERLY SWELL HEIGHTS BY A
FOOT OR SO, AND THE GFS WAVE WATCH MODEL WAS 1 TO 2 FEET HIGH AT
POHNPEI WHEN COMPARING TO BUOY OBSERVATIONS. AS SUCH, WE UNDERCUT
MODEL GUIDANCE BY 2 FEET TONIGHT AND BY A FOOT WEDNESDAY INTO
THURSDAY. THE NET EFFECT FROM THIS WAS LESS OF A POTENTIAL TO HIT
HIGH SURF CRITERIA AT POHNPEI, WITH LESS OF A CHANCE AT KOSRAE AS
WELL. HOWEVER, GIVEN THAT THIS WAS A RECENT CHANGE, WE ALSO OPTED TO
MAINTAIN THE CURRENT HEADLINES FOR BOTH LOCATIONS.
OTHERWISE, THE FORECAST REMAINS ON TRACK AS THE MODELS SHOW THE ITCZ
(INTER-TROPICAL CONVERGENCE ZONE) FRAGMENT WILL LIFT NORTH THE NEXT
48 TO 72 HOURS, AFFECTING POHNPEI AND KOSRAE. WITH THIS IN MIND,
SUPPORTED BY SATELLITE OBSERVATIONAL TRENDS, POPS (PROBABILITY OF
PRECIPITATION) WERE INCREASED AT THOSE LOCATIONS, WHILE ALSO
ADJUSTING TEMPERATURES DOWNWARD TO ACCOUNT FOR THIS.
AS FOR MARINE CONDITIONS, LOOK FOR MAINLY MODERATE TO FRESH WINDS TO
PREVAIL. SEAS OF 5 TO 7 FEET WILL INCREASE A FOOT OR SO, MAINLY LATE
WEDNESDAY EVENING INTO THURSDAY, BEFORE DECREASING FOR THE WEEKEND.
WESTERN MICRONESIA
THE MAIN WEATHER FEATURES AFFECTING WESTERN MICRONESIA ARE A TRADE-
WIND TROUGH JUST WEST OF CHUUK, THE NEAR-EQUATORIAL TROUGH SOUTH OF
KOROR, PALAU AND YAP, AND AN OLD SHEAR LINE FRAGMENT BETWEEN KOROR
AND CHUUK BEING BLOWN WESTWARD BY THE TRADE-WINDS.
CHUUK WILL HAVE SCATTERED SHOWERS TONIGHT, THEN ISOLATED WEDNESDAY
THROUGH THURSDAY AS THE TROUGH EXITS. A BRIEF SPLASH OF SCATTERED
COULD RE-EMERGE THURSDAY NIGHT, THEN ISOLATED AGAIN FRIDAY AND
SATURDAY. THE PERIOD ENDS SUNDAY WITH A RETURN TO SCATTERED SHOWERS.
WINDS WILL BE MAINLY 10 TO 15 KNOTS THROUGH THE PERIOD. SEAS OF 4 TO
6 FEET WILL BEGIN TO BUILD THURSDAY, PEAKING AT 7 TO 8 FEET THURSDAY
NIGHT, THEN DIMINISHING TO BETWEEN 5 AND 7 FEET FOR FRIDAY THROUGH
SUNDAY. THESE ARE BENIGN MARINE CONDITIONS, ALTHOUGH THE 8 FOOT SEAS
ARE AT THE UPPER END OF BENIGN.
YAP WILL FEATURE ISOLATED SHOWERS TONIGHT, SCATTERED SHOWERS
WEDNESDAY THROUGH FRIDAY, THEN ISOLATED SHOWERS AGAIN SATURDAY AND
SUNDAY. WINDS WILL BE MAINLY 10 TO 15 KNOTS THROUGH THE PERIOD. SEAS
OF 5 TO 7 FEET COULD BRIEFLY DIP TO BETWEEN 4 AND 6 FEET THURSDAY
NIGHT. THESE WILL LEAD TO BENIGN MARINE CONDITIONS FOR YAP THROUGH
THE ENTIRE FORECAST PERIOD.
KOROR, PALAU WILL SEE ISOLATED SHOWERS TONIGHT, SCATTERED SHOWERS
WEDNESDAY AND WEDNESDAY NIGHT, NUMEROUS SHOWERS THURSDAY AND THURSDAY
NIGHT, BACK TO SCATTERED SHOWERS FOR FRIDAY, AND DOWN TO ISOLATED
SHOWERS FOR SATURDAY AND SUNDAY. WINDS WILL BE 10 TO 15 KNOTS THROUGH
WEDNESDAY, THEN 5 TO 10 KNOTS THROUGH SUNDAY. SEAS WILL BE 5 TO 7
FEET THROUGH WEDNESDAY NIGHT, THEN 4 TO 6 FEET THROUGH SUNDAY. THESE
WILL LEAD TO BENIGN MARINE CONDITIONS FOR KOROR, PALAU THROUGH THE
ENTIRE FORECAST PERIOD.
GUM WATCHES/WARNINGS/ADVISORIES
GU...NONE.
MP...NONE.
MARIANAS WATERS...NONE.
MARIANAS: SCHANK/WHISNANT
EAST MICRONESIA: DOLL
WEST MICRONESIA: STANKO
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page