100
FXPQ50 PGUM 232119 CCA
AFDGUM
AREA FORECAST DISCUSSION...CORRECTED
NATIONAL WEATHER SERVICE TIYAN GU
719 AM CHST SAT JAN 24 2026
CORRECTED WESTERN MICRONESIA UPDATE TO DESCRIBE WHEN WAVES MIGHT
DIMINISH.
MARIANAS UPDATE
A BIG SHEAR LINE IS JUST TO THE NORTH AND NORTHWEST OF SAIPAN. THIS
WILL BRING WINDS AND WAVES TO THE MARIANAS SOON. HIGH SURF AND SMALL
CRAFT ADVISORIES ARE ALREADY OUT. RAIN HAS DISSIPATED OVER THE COURSE
OF LAST NIGHT, AND SHOULDN'T BE TOO MUCH TODAY EITHER, BUT COULD
STILL FILL IN TONIGHT OR SUNDAY. THE FORECAST HAD THIS WELL COVERED
SO NO MAJOR CHANGES WERE NEEDED.
MARINE
THE BUOYS INDICATE THE WAVES HAVEN'T ARRIVED YET, BUT OF COURSE THE
ONLY BUOY LEFT IN THE MARIANAS RIGHT NOW IS IPAN, AND ITS ON THE EAST
SIDE, WHEREAS THE WAVES ARE ON THE NORTHWEST SIDE. SO THE WAVES COULD
ALREADY BE HERE AND JUST AREN'T VISIBLE. THEY HAVE ARRIVED AT PALAU,
SO THEY ARE CERTAINLY CLOSE. BASED ON THE EVIDENCE AVAILABLE THOUGH,
NO CHANGES WERE NEEDED OVERNIGHT.
EASTERN MICRONESIA UPDATE
A TRADE-WIND TROUGH IS IMPINGING ON KOSRAE. RAISED THE POP'S FROM 30
TO 60 BASED ON SATELLITE PRESENTATION AND THE FACT THAT MOS PUT OUT
70 POP, MAKING KOSRAE NUMEROUS TODAY. OTHERWISE THE INHERITED
FORECAST WAS IN FINE SHAPE AND NO CHANGES WERE NEEDED.
WESTERN MICRONESIA UPDATE
HIGH WAVES IN YAP AND PALAU, ALTHOUGH THE WINDS ARE STILL NORTH OF
THEM FOR NOW AT LEAST. THE FORECAST HAD THIS WELL HANDLED, SO NO
CHANGES WERE NEEDED. THEY SHOULD BEGIN TO SETTLE DOWN OVER THE NEXT
DAY OR TWO.
PREV DISCUSSION
/ISSUED 655 PM CHST FRI JAN 23 2026/
MARIANAS SYNOPSIS...
PATCHY ISOLATED SHOWERS AND MOSTLY CLOUDY SKIES ARE SEEN ACROSS THE
MARIANAS, WITH SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS JUST
NORTH OF SAIPAN COASTAL WATERS. RECENT ALTIMETRY SHOWS COMBINED SEAS
OF 6 TO 8 FEET TO THE WEST OF GUAM WATERS.
DISCUSSION...
THE WEAK ELONGATED CIRCULATION PREVIOUSLY DESIGNATED AS INVEST 92W
BY THE JOINT TYPHOON WARNING CENTER SITS TO THE WEST OF THE
MARIANAS, CONNECTED WITH A BROAD SHEARLINE WHICH EXTENDS NORTHEAST
ACROSS THE NORTHERN CNMI, WITH MODERATE TO DEEP CONVECTION FOCUSED
ALONG THE BOUNDARY. THIS SHEARLINE WILL GRADUALLY DROP SOUTH ACROSS
THE MARIANAS OVER THE NEXT FEW DAYS, BRINGING BREEZY CONDITIONS AND
SCATTERED SHOWERS, WHICH MAY BECOME NUMEROUS AND LOCALLY HEAVY AT
TIMES. THE SHEARLINE AND ASSOCIATED WINDS AND SHOWERS WILL ARRIVE
FIRST TO TINIAN AND SAIPAN AROUND SUNDAY EVENING, DESCENDING FURTHER
SOUTH OVER ROTA AND GUAM WATERS THROUGH MONDAY NIGHT, THEN GRADUALLY
BREAKING DOWN AS IT MOVES AWAY TO THE WEST AROUND MIDWEEK. FOR NOW,
FAIRLY QUIET CONDITIONS ARE EXPECTED, ESPECIALLY FOR GUAM AND ROTA
AS WINDS DIMINISH OVER THE NEXT DAY OR TWO, BECOMING LIGHT AND
VARIABLE SUNDAY JUST SOUTH OF THE SHEARLINE. WINDS WILL GRADUALLY
SHIFT TO THE NORTHEAST THROUGH SUNDAY EVENING, AND WILL REMAIN
SUFFICIENTLY LIGHT DURING THE DAYTIME TO SUPPORT POSSIBLE ISLAND
EFFECT SHOWERS OVER GUAM IN THE AFTERNOON. UNCERTAINTY IS STILL HIGH
AS THIS WILL DEPEND STRONGLY ON A FAVORABLE WIND AND CLOUD FORECAST,
BUT THIS SETUP COULD LEAD TO PERIODS OF HIGHLY LOCALIZED HEAVY
RAINFALL OVER THE ISLAND THROUGH SUNDAY AFTERNOON.
MARINE/SURF...
COMBINED SEAS AROUND 6 TO 8 FEET WILL INCREASE TO LEVELS HAZARDOUS
TO SMALL CRAFT SATURDAY EVENING, DUE TO A SIGNIFICANT PULSE OF
NORTHWEST TO NORTH SWELL AND ELEVATED WIND WAVES, STEMMING FROM A
DESCENDING SHEARLINE. THIS WILL ALSO BRING HAZARDOUS SURF EXCEEDING
9 FEET AND A HIGH RISK OF RIP CURRENTS TO WEST AND NORTH FACING
REEFS. SEAS WILL RISE TO EXCEED 10 FEET DUE TO THE SWELLS BEFORE THE
HIGHER WINDS ARRIVE, FIRST ALONG MAINLY THE NORTHERN AND WESTERN
COASTAL WATERS. THE SHEARLINE, AND ASSOCIATED STRONG WINDS, WILL
ARRIVE FIRST TO TINIAN AND SAIPAN SUNDAY, DESCENDING FURTHER SOUTH
OVER ROTA AND GUAM WATERS MONDAY, BEFORE WIND SPEEDS GRADUALLY RELAX
BELOW HAZARDOUS LEVELS EARLY NEXT WEEK. IN THE MEANTIME, MODERATE TO
FRESH WINDS WILL DIMINISH TO BECOME LIGHT TO GENTLE OVER THE NEXT
FEW DAYS, BEFORE PICKING BACK UP SUNDAY NIGHT, ESPECIALLY FOR TINIAN
AND SAIPAN WITH BREEZY CONDITIONS EXPECTED THROUGH EARLY NEXT WEEK.
EASTERN MICRONESIA...
SATELLITE IMAGERY SHOWS PARTLY CLOUDY SKIES WITH ISOLATED TO
SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS. ALTIMETRY AND BUOY
DATA SHOW COMBINED SEAS BETWEEN 4 AND 6 FEET ACROSS THE REGION.
A DRY TRADE-WIND PATTERN WITH EMBEDDED TRADE-WIND TROUGHS HAS
ESTABLISHED ITSELF ACROSS EASTERN MICRONESIA. ISOLATED SHOWERS LOOK
TO PREVAIL ACROSS POHNPEI, KOSRAE, AND MAJURO THROUGH MUCH OF THE
PERIOD. KOSRAE COULD SEE ANOTHER ROUND OF SCATTERED SHOWERS TOMORROW
BEFORE BECOMING ISOLATED THROUGH THE PERIOD. A MORE ACTIVE PATTERN
APPEARS POSSIBLE LATE NEXT WEEK AS A NEAR EQUATORIAL TROUGH (NET)
DEVELOPS.
BENIGN COMBINED SEAS OF 4 TO 6 FEET WILL PERSIST THROUGH TUESDAY
NIGHT BEFORE SEAS START TO RISE IN RESPONSE TO A LONG PERIOD NORTH
SWELL. SEAS LOOK TO REMAIN BELOW HAZARDOUS CONDITIONS ACROSS EASTERN
MICRONESIA, BUT SURF COULD BECOME HAZARDOUS FOR NORTH FACING REEFS
OF POHNPEI AND KOSRAE.
WESTERN MICRONESIA...
LATEST SATELLITE IMAGERY SHOWS PARTLY CLOUDY SKIES WITH ISOLATED
SHOWERS ACROSS WESTERN MICRONESIA, WITH SCATTERED TO NUMEROUS
SHOWERS SEEN NORTHWEST OF PALAU. ALTIMETRY SHOWS SEAS BETWEEN 8 AND
11 FEET OVER WESTERN PALAU WATERS, WITH SOFAR BUOY TO THE NORTHWEST
OF PALAU SHOWING SEAS OF 12 TO 14 FEET. ALTIMETRY SHOWS SEAS OVER
YAP BETWEEN 7 AND 9 FEET, AND BETWEEN 4 AND 6 FEET AT WENO.
THE DRY PATTERN IS SOLIDLY IN PLACE OVER WESTERN MICRONESIA AND
LOOKS TO CONTINUE THROUGH AT LEAST THE MIDDLE OF NEXT WEEK. HOWEVER,
THERE IS A BAND OF STRONG CONVECTION BACKBUILDING INTO THE EXTREME
SOUTHWESTERN PALAU WATERS. SHOWERS ARE NOT EXPECTED TO INCREASE
ABOVE ISOLATED FOR NOW, WITH THUNDERSTORMS EXPECTED TO REMAIN OUTSIDE
OF THE COASTAL WATERS AT PALAU, BUT WILL WATCH THIS CLOSELY OVER THE
NEXT COUPLE OF HOURS FOR ANY INDICATIONS THAT THIS WILL CHANGE.
THE MAIN CONCERN REVOLVES AROUND THE BUILDING NORTHWEST SWELL OVER
PALAU AND YAP. THE LATEST ALTIMETRY DATA NOW SHOWS SEAS OF 8 TO 11
FEET OVER WESTERN PALAU WATERS. THIS IS AVERAGING AROUND 2 FEET
HIGHER THAN WAVEWATCH GUIDANCE. BASED ON ALTIMETRY, A SMALL CRAFT
ADVISORY WAS ISSUED FOR PALAU STARTING THIS AFTERNOON, AND FOR YAP
STARTING SATURDAY MORNING. THESE SEAS ARE DUE TO A BUILDING
NORTHWEST SWELL PRODUCED BY A STRONG SHEAR LINE CURRENTLY SEEN NORTH
OF 10N. SEAS WILL GRADUALLY SUBSIDE SATURDAY NIGHT AT PALAU, FALLING
BELOW 10 FEET EARLY SUNDAY MORNING. FOR YAP, SEAS WILL GRADUALLY
SUBSIDE SUNDAY NIGHT, FALLING BELOW 10 FEET EARLY MONDAY MORNING.
FOR CHUUK, SEAS LOOK TO BE BETWEEN 3 AND 6 FEET THROUGH THE
BEGINNING OF NEXT WEEK, THEN BEGIN TO BUILD AS THE NORTHWEST SWELL
REACHES WENO. THE LARGE NORTHWEST SWELL WILL ALSO CONTINUE TO
PRODUCE HAZARDOUS SURF CONDITIONS THROUGH THE BEGINNING OF NEXT WEEK
ALONG WEST AND NORTH FACING REEFS OF YAP AND PALAU. WINDS LOOK TO
REMAIN LIGHT TO GENTLE THROUGH THE BEGINNING OF NEXT WEEK AT PALAU
AND YAP, BECOMING OCCASIONALLY MODERATE TUESDAY AT YAP. LIGHT TO
GENTLE WINDS AT CHUUK WILL BECOME GENTLE TO MODERATE OVER THE WEEKEND
AND MODERATE TO FRESH AROUND THE MIDDLE OF NEXT WEEK.
GUM WATCHES/WARNINGS/ADVISORIES
GU...HIGH RIP CURRENT RISK FROM THIS EVENING THROUGH MONDAY AFTERNOON
FOR GUZ001.
HIGH SURF ADVISORY FROM 6 PM THIS EVENING TO 6 PM CHST MONDAY FOR
GUZ001.
MP...HIGH RIP CURRENT RISK FROM THIS EVENING THROUGH MONDAY AFTERNOON
FOR MPZ001>003.
HIGH SURF ADVISORY FROM 6 PM THIS EVENING TO 6 PM CHST MONDAY FOR
MPZ001>003.
MARIANAS WATERS...SMALL CRAFT ADVISORY FROM 6 PM THIS EVENING TO 6 PM CHST MONDAY FOR
PMZ151>154.
MARIANAS/EAST AND WEST MICRONESIA UPDATE: STANKO
MARIANAS: DECOU
EAST MICRONESIA: WILLIAMS
WEST MICRONESIA: KLEESCHULTE
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