198
FXPQ50 PGUM 060813
AFDGUM
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TIYAN GU
613 PM CHST TUE JAN 6 2026
MARIANAS SYNOPSIS
THERE IS A HIGH SURF ADVISORY (HSA) ALONG NORTH FACING REEFS AND A
HIGH RISK OF RIP CURRENTS (HRRC) STATEMENT ALONG NORTH AND EAST
FACING REEFS.
SATELLITE IMAGERY SHOWS PARTLY CLOUDY TO MOSTLY CLOUDY SKIES, WHILE
RADAR IMAGERY SHOWS LOW-END SCATTERED SHOWERS OVER THE REGION. BUOY
DATA SHOWS ABOUT 5 TO 6 FEET SWELLS AND 8 SECOND PERIODS AT IPAN.
DISCUSSION
THE SHEAR LINE IS LOCATED BETWEEN ROTA AND TINIAN. THIS FEATURE IS
PRODUCING PARTLY CLOUDY TO MOSTLY CLOUDY SKIES AND SCATTERED SHOWERS.
THIS FEATURE IS EXPECTED TO GRADUALLY WEAKEN OVER THE NEXT COUPLE OF
DAYS. THEN, DRIER TRADE-WIND PATTERN IS EXPECTED FOR THE REST OF THE
WEEK, WITH ONE CAVEAT, WINDS ARE ANTICIPATED TO BUILD SLIGHTLY FROM
15 TO 20 MPH TO 20 TO 25 MPH FOR FRIDAY.
MARINE/SURF
A NORTH SWELL CONTINUES TO MOVE THROUGH THE REGION, SUPPORTING SEAS
OF 7 TO 9 FEET, AND IS EXPECTED TO GRADUALLY SUBSIDING OVER THE NEXT
COUPLE OF DAYS. MODERATE TO FRESH NORTHEAST WINDS WILL THEN CONTINUE
THROUGH THE END OF THE WEEK, WITH SLIGHTLY HIGHER WINDS ON FRIDAY.
COMBINED SEAS WILL GRADUALLY SUBSIDE TO 5 TO 7 FEET THURSDAY, THEN
INCREASE BACK UP TO 7 TO 9 FEET SATURDAY WITH AN INCREASE IN EAST
SWELL AND WIND WAVES AS THE TRADES ARE EXPECTED TO BUILD.
WITH THE NORTH SWELL EXPECTED TO GRADUALLY SUBSIDE OVER THE NEXT
COUPLE OF DAYS, THIS WILL ALLOW FOR THE TRADE SWELL TO TAKE OVER
BEING THE DOMINANT SWELL. THIS WILL BRING THE SURF ALONG NORTH AND
WEST FACING REEFS DOWN, HOWEVER, WILL KEEP SURF ALONG EAST FACING
REEFS UP. NEAR THE BEGINNING OF NEXT WEEK THE TRADES ARE EXPECT TO
BEGIN BUILDING AGAIN.
EASTERN MICRONESIA
LATEST SATELLITE IMAGERY SHOWS MOSTLY DRY CONDITIONS ACROSS EASTERN
MICRONESIA, WITH DEEP CONVECTION SEEN TO THE NORTHEAST AND SOUTHEAST
OF MAJURO. POHNPEI BUOY SHOWS SEAS BETWEEN 5 AND 6 FEET. ALTIMETRY
AND SOFAR BUOY SHOWS SEAS OF 8 FEET NORTH OF 10N.
A QUIET DRY PATTERN CONTINUES ACROSS EASTERN MICRONESIA THIS
AFTERNOON, WITH ISOLATED SHOWERS SEEN ACROSS POHNPEI AND KOSRAE AND
ISOLATED LIGHT SHOWERS AT MAJURO. BOTH POHNPEI AND KOSRAE LOOK TO
REMAIN DRY FOR THE NEXT COUPLE OF DAYS. FOR MAJURO, A VERY STRONG
UPPER-LEVEL LOW IS SEEN TO THE NORTH-NORTHEAST OF THE ATOLL, WITH A
TROUGH EXTENDING NORTHEAST AND SOUTHWEST FROM THE LOW. BOTH SPEED AND
DIRECTIONAL DIVERGENCE ASSOCIATED WITH THIS LOW IS EXPECTED TO MOVE
OVER THE MARSHALLS AS THE LOW CONTINUES TO DRIFT WEST. DUE TO LOW
CONFIDENCE IN THE MOVEMENT OF THIS FEATURE, DECIDED TO MAINTAIN LOW-
END SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS AT MAJURO STARTING
WEDNESDAY MORNING THROUGH WEDNESDAY NIGHT, WITH SCATTERED SHOWERS
CONTINUING INTO THURSDAY. BY THURSDAY NIGHT, THE DRY PATTERN LOOKS TO
RETURN TO THE MARSHALLS AND CONTINUE THROUGH THE WEEKEND. AFFECTS OF
THE LOW LOOK TO REMAIN NORTH OF POHNPEI AND KOSRAE AS IT TURNS MORE
NORTHWEST. HOWEVER, AN APPROACHING TRADE-WIND TROUGH LOOKS TO BRING
INCREASED CONVECTION TO KOSRAE OVER THE WEEKEND.
NOT MUCH HAS CHANGED FOR THE MARINE FORECAST. SEAS LOOK TO BUILD A
BIT THROUGH WEDNESDAY, THEN SUBSIDE FOR THE NEXT COUPLE OF DAYS FOR
POHNPEI AND KOSRAE. AT MAJURO, SEAS WILL REMAIN AROUND 3 TO 5 FEET
THROUGH THURSDAY. BY THURSDAY NIGHT, A BUILDING TRADE SWELL WILL
BEGIN TO MOVE THROUGH THE REGION, INCREASING SEAS TO BETWEEN 6 AND 8
FEET BY SATURDAY. THIS BUILDING TRADE SWELL WILL APPROACH KOSRAE
SATURDAY, INCREASING SEAS TO AS HIGH AS 8 FEET AT POHNPEI AND 7 FEET
AT KOSRAE.
WESTERN MICRONESIA
SATELLITE IMAGERY CONTINUES A FAIRLY DRY TRADE-WIND PATTERN ACROSS
THE REGION, WITH PRECIPITABLE WATER VALUES BETWEEN 1.20 AND 1.50
INCHES ACROSS MOST OF THE REGION. MODEL GUIDANCE CONTINUES TO SUPPORT
THIS DRY AIR LINGERING THROUGH AT LEAST THURSDAY SO THIS SHOULD
SUPPORT DRY CONDITIONS ACROSS CHUUK, YAP AND PALAU OVER THE NEXT
COUPLE OF DAYS. THE SHEAR LINE UP NEAR THE MARIANAS IS WEAKENING AND
MODELS CONTINUE TO SHOW THIS FEATURE WEAKENING AS IT LOSES ITS NARROW
AND SHARP GRADIENT IN WIND SPEED. HOWEVER, THE GFS AND ECMWF SHOW
THE AREA OF INCREASED CLOUD COVER ASSOCIATED WITH THE DECAYING SHEAR
LINE SHIFTING TOWARDS PALAU AND YAP AROUND THURSDAY AND FRIDAY, WHICH
COULD LEAD A SLIGHT INCREASE IN SHOWERS IF THIS FEATURE HOLDS
TOGETHER. OTHERWISE, MODELS SHOW WINDS INCREASING TO MODERATE TO
FRESH AROUND FRIDAY AND SATURDAY, POTENTIALLY BECOMING STRONG AROUND
YAP AND OTHER ISLAND NEAR 10N AS A RIDGE OF HIGH PRESSURE BUILDS IN
THE MID-LATITUDES. THIS SURGE IN THE TRADE WINDS MAY CREATE AN AREA
OF SPEED CONVERGENCE ACROSS THE REGION THAT COULD CAUSE THE POTENTIAL
FOR SHOWERS TO INCREASE ACROSS THE REGION THIS WEEKEND.
THE DRIFTING BUOY BETWEEN PALAU AND YAP HAS SHOWN A DECREASE IN SEAS
FROM AROUND 8 FEET TO BETWEEN 6 AND 7 FEET OVER THE PAST 24 HOURS,
SUPPORTING THAT THE NORTHERLY SWELL IS DECREASING. BASED ON THIS
DATA, ALONG WITH MODEL GUIDANCE, THE HIGH SURF ADVISORY HAS ALLOWED
TO EXPIRE AS 9 FOOT SURF OR GREATER ALONG NORTH FACING REEFS IS NO
LONGER EXPECTED. THE HIGH SURF ADVISORY ALONG WEST AND NORTH FACING
REEFS OF CHUUK CONTINUE THROUGH TONIGHT. MODEL GUIDANCE AND ALTIMETRY
DATA SUPPORTS THAT THE PEAK OF THE NORTH-NORTHWEST SWELL HAS
OCCURRED AND WILL SLOWLY DECREASE OVERNIGHT. BASED ON LATEST MODEL
TRENDS, SURF IS EXPECTED TO DROP BELOW 9 FEET ALONG WEST AND NORTH
FACING REEFS WEDNESDAY MORNING. LOOKING TOWARDS THE WEEKEND, THE
TRADE WINDS ARE EXPECTED TO INCREASE TO MODERATE TO FRESH, AND
POTENTIALLY BECOMING STRONG AROUND YAP AND OTHER ISLANDS NEAR 10N AS
A RIDGE OF HIGH PRESSURE BUILDS IN THE MID-LATITUDES. THIS SURGE IN
THE TRADE WINDS WILL BUILD THE NORTHEAST TO EAST TRADE SWELL AND
LOCAL WIND WAVES, INCREASING SEAS, AND SURF ALONG EAST FACING REEFS.
THERE IS THE POTENTIAL THAT HAZARDOUS SEAS OF AT LEAST 10 FEET AND
WINDS OF 22 KT WILL DEVELOP ACROSS THE REGION THIS WEEKEND.
GUM WATCHES/WARNINGS/ADVISORIES
GU...HIGH RIP CURRENT RISK THROUGH WEDNESDAY AFTERNOON FOR GUZ001.
HIGH SURF ADVISORY UNTIL 4 PM CHST WEDNESDAY FOR GUZ001.
MP...HIGH RIP CURRENT RISK THROUGH WEDNESDAY AFTERNOON FOR MPZ001>003.
HIGH SURF ADVISORY UNTIL 4 PM CHST WEDNESDAY FOR MPZ001>003.
MARIANAS WATERS...NONE.
MARIANAS: BOWSHER
EAST MICRONESIA: KLEESCHULTE
WEST MICRONESIA: SCHANK
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