096
FXPQ50 PGUM 270035
AFDGUM
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TIYAN GU
1035 AM CHST TUE JAN 27 2026
MARIANAS UPDATE
THE SHEAR LINE REMAINS WITHIN THE MARIANAS. IT IS SLOWLY WEAKENING,
BUT IS STILL PACKING ENOUGH OF A PUNCH ON ROTA THAT WE NEEDED TO
ISSUE AN FLS THIS MORNING. THE FORECAST HAS SCATTERED SHOWERS FOR ALL
LOCATIONS, AND MOST ARE RECEIVING, AND COULD RECEIVE MORE IF THE
SHEAR LINE STARTS UNDULATING, WHICH THEY SOMETIMES DO. NO CHANGES
WERE NEEDED THIS MORNING BECAUSE THE SHEAR LINE WAS COVERED WITH
SHOWERS IN UNTIL THURSDAY.
MARINE
THE WINDS AND WAVES WITH THE SHEAR LINE ARE STILL HIGHER THAN USUAL.
UNFORTUNATELY ALL OUR NORTHWARD FACING BUOYS ARE OUT. HOWEVER,
ALTIMETER AND MODEL DATA INDICATE TINIAN AND SAIPAN STILL HAVE
MINIMAL SMALL CRAFT CRITERIA, AND IT SHOULD DIMINISH THIS AFTERNOON.
FOR NOW WE'RE GOING WITH THAT, WHILE THE SMALL CRAFT ADVISORY FOR
ROTA WAS ALLOWED TO EXPIRE WITH SEAS DROPPING BELOW 10 FEET AND WINDS
BELOW 22 KT.
EASTERN MICRONESIA UPDATE
EASTERN MICRONESIA JUST HAS A NEAR-EQUATORIAL TROUGH SOUTH OF THE
MAJOR FORECAST LOCATIONS AND A COUPLE OF WEAK TRADE-WIND TROUGHS.
RAISED THE CLOUDS AT POHNPEI FROM PARTLY CLOUDY TO PARTLY SUNNY TO
ACCOUNT FOR ONE OF THESE. THAT WAS THE ONLY CHANGE NEEDED, KOSRAE AND
MAJURO WERE ALREADY PARTLY SUNNY.
WESTERN MICRONESIA UPDATE
THE WESTERN MICRONESIA FORECAST WAS ALREADY HIGH AND DRY, AND SO IT
IS. NO CHANGES WERE NEEDED, THE SHEAR LINE IS NORTH OF ALL FORECAST
LOCATIONS, AND NOW BEGINNING TO WEAKEN. THE SAME GOES FOR INVEST AREA
93W, WHICH IS NEAR THE BORDER OF OUR AREA WITH THAT OF PAGASA.
PREV DISCUSSION
/ISSUED 628 PM CHST MON JAN 26 2026/
MARIANAS SYNOPSIS...
VISIBLE SATELLITE IMAGERY SHOWS MOSTLY CLOUDY TO CLOUDY SKIES ACROSS
THE REGION, WHILE RADAR IMAGERY INDICATES SHOWERS ALONG A SHEAR LINE
DECREASING THROUGH THE AFTERNOON. ALTIMETRY SHOWS HAZARDOUS SEAS OF
9 TO 11 FEET ACROSS THE CNMI, WITH SEAS UP TO 13 FEET WEST OF TINIAN
AND SAIPAN COASTAL WATERS.
DISCUSSION...
A SHEAR LINE THAT BROUGHT HEAVY RAINFALL AND STRONG TO NEAR-GALE
GUSTS TO THE CNMI OVERNIGHT AND THIS MORNING, BEGAN TO WEAKEN THIS
AFTERNOON. 24 HOUR RAINFALL ACCUMULATIONS REVEAL A SIGNIFICANT
DIFFERENCE IN CONDITIONS, SHOWING 6.10 INCHES AT THE AIRPORT ON
SAIPAN AND 0.21 INCHES AT THE AIRPORT ON GUAM. WIND GUSTS PEAKED AT
AROUND 35 MPH OVERNIGHT AND EARLY THIS MORNING FOR THE CNMI, WHERE
THE SHEAR LINE LINGERED, BUT AN OUTFLOW BOUNDARY MOVING SOUTHWARD
ACROSS GUAM ALSO BROUGHT WIND GUSTS AROUND 30 MPH THIS MORNING.
THESE OBSERVATIONS LED TO A SERIES OF FLOOD ADVISORIES AND A WIND
ADVISORY ISSUED EARLIER TODAY. ALTHOUGH SHOWERS ARE BREAKING APART
THIS AFTERNOON AND OVERALL THE FEATURE HAS WEAKENED, IT REMAINS
SITUATED ACROSS THE REGION OVER THE NEXT COUPLE DAYS, WITH LOCALLY
HEAVY SHOWERS AND STRONGER GUSTS POSSIBLE THROUGH TUESDAY, MAINLY
ACROSS THE CNMI. LATE WEEK AND OVER THE WEEKEND, ANOTHER SHEAR LINE
FRAGMENT MAY SET UP AGAIN, INCREASING WINDS TO MODERATE TO FRESH.
ALTHOUGH SHOWERS LOOK TO BE ISOLATED TO SCATTERED ACROSS THE
MARIANAS.
MARINE/SURF...
A SHEAR LINE CONTINUES TO PRODUCE MODERATE TO STRONG WINDS, ELEVATED
WIND WAVES, AND NORTHEAST SWELL. A SMALL CRAFT ADVISORY EXPIRES THIS
AFTERNOON FOR GUAM SINCE SEAS HAVE SUBSIDED TO 6 TO 8 FEET, BUT
WINDS GREATER THAN 22 KT CONTINUE ACROSS NORTHWESTERN ROTA WATERS, SO
THE SMALL CRAFT ADVISORY WAS EXTENDED THROUGH TONIGHT. FOR TINIAN
AND SAIPAN, A SMALL CRAFT ADVISORY REMAINS IN EFFECT THROUGH TUESDAY
AFTERNOON. LOCALLY HEAVY SHOWERS AND CONVECTIVELY-DRIVEN GUSTS TO 30
KT ARE EXPECTED THROUGH TUESDAY NIGHT, MAINLY ACROSS THE CNMI.
COMBINED SEAS OF 6 TO 8 FEET FOR GUAM AND 7 TO 10 FT FOR THE CNMI
GRADUALLY DECREASE AROUND MIDWEEK AS THE SHEAR LINE WEAKENS. LATE
WEEK AND OVER THE WEEKEND, ANOTHER SHEAR LINE FRAGMENT MAY SET UP
AGAIN, WITH WINDS INCREASING TO MODERATE TO FRESH AND SEAS
INCREASING TO 7 TO 9 FEET, POSSIBLY UP TO HAZARDOUS LEVELS OF 10
FEET AT TINIAN AND SAIPAN.
SURF ALONG NORTH AND WEST FACING REEFS HAS DECREASED BELOW HAZARDOUS
LEVELS, BUT ANOTHER PULSE OF NORTH TO NORTHWEST SWELL ARRIVES EARLY
TUESDAY MORNING, ALLOWING SURF TO INCREASE BACK UP TO HAZARDOUS
LEVELS OF 9 FEET AND RIP RISK TO INCREASE BACK TO HIGH FOR WEST AND
NORTH FACING REEFS. THE HIGH SURF ADVISORY HAS BEEN EXTENDED THROUGH
WEDNESDAY NIGHT, WHILE ACKNOWLEDGING THE SURF IS EXPECTED TO
MOMENTARILY DECREASE BELOW HAZARDOUS LEVELS TONIGHT. BY TUESDAY
NIGHT OR WEDNESDAY, SURF ALONG WEST FACING REEFS MAY DECREASE BELOW
HAZARDOUS LEVELS, BUT HAZARDOUS SURF ALONG NORTH FACING REEFS IS
EXPECTED TO CONTINUE THROUGH LATE WEDNESDAY NIGHT. A MODERATE RISK
OF RIP CURRENTS ALONG EAST FACING REEFS CONTINUES THROUGH WEDNESDAY.
EASTERN MICRONESIA...
A MOSTLY DIFFUSIVE AND DRY TRADE-WIND REGIME INDUCED BY A
COMBINATION OF TWO SUBSECTIONS OF THE NEAR-EQUATORIAL TROUGH
(NET),AND AN EXTENSIVE EAST-WEST ORIENTED SUBTROPICAL RIDGE ACROSS
WAKE ISLAND, IS EXPECTED TO CONTINUE ACROSS MUCH OF EASTERN
MICRONESIA THE NEXT SEVERAL DAYS. MOSTLY ISOLATED SHOWERS ARE
EXPECTED FOR MUCH OF THE WEEK, EXCEPT FOR A SMALL UPTICK IN SHOWER
COVERAGE OVER KOSRAE AROUND MIDWEEK AND COMING UP ON THE WEEKEND, AS
MINOR SURFACE TROUGHS FORM UPSTREAM. ANOTHER MINOR TROUGH IS
EXPECTED TO FORM JUST NEAR THE DATE LINE, BRINGING LOW-END SCATTERED
SHOWERS TO MAJURO TUESDAY. SIGNIFICANT SHOWER POTENTIALS ARE NOT
EXPECTED TO DEVELOP UNTIL NEXT WEEK, WHEN A MORE PRONOUNCED ITCZ MAY
DEVELOP.
COMBINED SEAS OF 5 TO 6 FEET ARE EXPECTED TO INCREASE A FEW FEET IN
THE SECOND HALF OF THE WEEK, AS NORTHEASTERLY SWELL AND LOCALIZED
WIND WAVES CONTINUE TO INCREASE.
WESTERN MICRONESIA...
LATEST SATELLITE IMAGERY SHOWS PARTLY CLOUDY SKIES WITH ISOLATED
LIGHT SHOWERS ACROSS THE REGION. ALTIMETRY WAS NOT AVAILABLE FOR
PALAU, HOWEVER, IT SHOWS SEAS BETWEEN 9 AND 11 FEET AT YAP PROPER
AND 5 TO 7 FEET OVER CHUUK.
A DRY PATTERN CONTINUES ACROSS WESTERN MICRONESIA THIS EVENING, WITH
ONLY SPOTTY LIGHT SHOWERS SEEN AT ALL THREE FORECAST POINTS. THIS IS
EXPECTED TO CHANGE THE LAST HALF OF THE WORK WEEK AT CHUUK AS A
TRADE-WIND TROUGH MOVES INTO THE STATE FROM EASTERN MICRONESIA.
MODEL GUIDANCE IS SHOWING THE POTENTIAL FOR HEAVIER RAINFALL AT WENO
OVER THE WEEKEND. FOR YAP, THE DRY PATTERN LOOKS TO END EARLY IN THE
WEEKEND AND LATER IN THE WEEKEND FOR PALAU, AS THE TROUGH MOVES
SLOWLY THROUGH THE AREA AND BEGINS TO INTERACT WITH THE SHEAR LINE
CURRENTLY NORTH OF 10N.
SEAS CONTINUE TO SLOWLY SUBSIDE FOR YAP AND PALAU, WITH PALAU STILL
SEEING ELEVATED SEAS NEAR 9 FEET, WHILE YAP CAN EXPECT SEAS OF 8 TO
11 FEET THROUGH TONIGHT, LIKELY FALLING BELOW 10 FEET BY EARLY
TUESDAY MORNING. HOWEVER, SEAS WILL REMAIN ELEVATED THROUGH TUESDAY
AFTERNOON, PRODUCING HAZARDOUS SURF ALONG NORTH FACING REEFS OF YAP
AND PALAU. FOR CHUUK, SEAS OF 5 TO 7 FEET ARE EXPECTED TO SLOWLY
BUILD THROUGH THE WEEK, REACHING 6 TO 8 FEET AROUND MIDWEEK. WINDS
WILL BE GENTLE TO MODERATE THROUGH THE WEEK AT CHUUK, AND MOSTLY
LIGHT TO GENTLE AT YAP AND PALAU, WITH PALAU SEEING GENTLE TO
MODERATE WINDS FOR THE WEEKEND.
GUM WATCHES/WARNINGS/ADVISORIES
GU...HIGH RIP CURRENT RISK THROUGH LATE WEDNESDAY NIGHT FOR GUZ001.
HIGH SURF ADVISORY UNTIL 6 AM CHST THURSDAY FOR GUZ001.
MP...HIGH RIP CURRENT RISK THROUGH LATE WEDNESDAY NIGHT FOR MPZ001>003.
HIGH SURF ADVISORY UNTIL 6 AM CHST THURSDAY FOR MPZ001>003.
MARIANAS WATERS...SMALL CRAFT ADVISORY UNTIL 5 PM CHST THIS AFTERNOON FOR PMZ153-154.
MARIANAS/EAST AND WEST MICRONESIA UPDATE: STANKO
MARIANAS: CRUZ
EAST MICRONESIA: MONTVILA
WEST MICRONESIA: KLEESCHULTE
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