906
FXPQ50 PGUM 210747
AFDGUM
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TIYAN GU
547 PM CHST SAT MAR 21 2026
MARIANAS SYNOPSIS
MODERATE TO FRESH NORTHEAST WINDS AND ISOLATED TO SCATTERED SHOWERS
PREVAIL ACROSS THE REGION THIS AFTERNOON. A TRADE-WIND TROUGH THAT
MOVED THROUGH TODAY IS NOW WEST OF THE REGION. RADAR OBSERVATIONS
SHOW SCATTERED SHOWERS LINGER ACROSS WESTERN WATERS OF GUAM AND ROTA
AND ARE EXPECTED TO MOVE OUT OF COASTAL WATERS BY LATE TONIGHT. A
SMALL CRAFT ADVISORY REMAINS IN EFFECT THROUGH SUNDAY AFTERNOON FOR
SEAS OF 7 TO 10 FEET. A HIGH SURF ADVISORY FOR NORTH-FACING REEFS AND
A HIGH RISK OF RIP CURRENTS ALONG NORTH- AND EAST-FACING REEFS
REMAIN IN EFFECT THROUGH SUNDAY AFTERNOON AS WELL.
DISCUSSION
AFTER SCATTERED SHOWERS IN THE WAKE OF A TRADE-WIND TROUGH MOVES
WEST OF COASTAL WATERS, MODERATE TO STRONG NORTHEAST WINDS AND
ISOLATED SHOWERS ARE EXPECTED THROUGH SUNDAY NIGHT. A WEAK
CIRCULATION IN SOUTHERN CHUUK STATE IS PRODUCING A BROAD AREA OF
SHOWERS WELL TO THE SOUTHEAST OF THE MARIANAS. SHOWERS ALONG THE
NORTHERN PERIPHERY OF THIS DISTURBANCE IS EXPECTED TO BRING AN
INCREASE IN SHOWERS MONDAY THROUGH WEDNESDAY, WITH A SLIGHTLY HIGHER
SHOWER COVERAGE AND THUNDERSTORM POTENTIAL FOR GUAM AND ROTA. AS THIS
DISTURBANCE PASSES WELL TO THE SOUTH, AN AREA OF HIGH PRESSURE
PUSHES EASTWARD OFF THE COAST OF JAPAN, TIGHTENING THE PRESSURE
GRADIENT ACROSS THE MARIANAS. THIS WILL RESULT IN BREEZIER CONDITIONS
THROUGH MONDAY NIGHT OR TUESDAY.
MARINE/SURF
ELEVATED NORTHEAST TO EAST SWELL AND WIND WAVES, AND LONG-PERIOD
NORTH TO NORTHEAST SWELL CONTINUES TO PRODUCE HAZARDOUS SEAS UP
TO 10 FEET WITHIN THE EASTERN MARIANAS COASTAL WATERS, WITH 7 TO 9
FEET EXPECTED WEST OF THE ISLANDS. COMBINED SEAS MAY BRIEFLY
DIMINISH AROUND SUNDAY NIGHT, INCREASING ONCE MORE THROUGH MONDAY
AS A TRADE-WIND SURGE INCREASES NORTHEAST SWELL AND WIND WAVES.
WINDS WILL BE MODERATE TO FRESH OUT OF THE NORTHEAST TO EAST, BRIEFLY
BECOMING MODERATE TO STRONG MONDAY AND MONDAY NIGHT, THEN GRADUALLY
DIMINISHING TO LIGHT TO GENTLE LATE WEEK. AN EXTENSION OR ANOTHER
ISSUANCE OF A SMALL CRAFT ADVISORY WILL LIKELY BE NEEDED FOR
HAZARDOUS CONDITIONS FOR MONDAY AND MONDAY NIGHT. HAZARDOUS SURF
ALONG NORTH FACING REEFS AND A HIGH RISK OF RIP CURRENTS ALONG NORTH
AND EAST FACING REEFS CONTINUES THROUGH AT LEAST SUNDAY AFTERNOON.
SWELLS, SURF, AND RIP CURRENT RISK WILL THEN BRIEFLY DIMINISH,
ALTHOUGH THE INCREASE IN NORTHEAST TO EAST TRADE-WIND SWELL MAY
INCREASE THE RIP RISK ALONG EAST-FACING REEFS BACK UP TO HIGH AROUND
MONDAY NIGHT. A MODERATE RISK OF RIP CURRENTS WILL CONTINUE ALONG
WEST AND SOUTH FACING REEFS THROUGH TONIGHT, BEFORE RIP RISK ALONG
WEST REEFS DECREASES TO LOW FOR SUNDAY.
EASTERN MICRONESIA
THE FORECAST REMAINS IN GREAT SHAPE WITH MINIMAL CHANGES NEEDED TO
THE ENTIRE FORECAST, MAINLY TO ADJUST TEMPS UPWARD AT POHNPEI AND
KOSRAE, AS BOTH HIT 90 TODAY. MAJURO HAD A HIGH OF 88, BUT
CONVECTIVE DEBRIS MAY HELP TEMPER AFTERNOON HIGHS TOMORROW. AN
OUTFLOW BOUNDARY PUSHING SOUTH WILL FOCUS INCREASED CONVECTIVE
DEVELOPMENT. AS SUCH, WE INCREASED RAINFALL PROBABILITIES TO 50
PERCENT. WE CONTEMPLATED GOING WITH HIGHER POTENTIAL THAN THAT, BUT
QUESTIONS AS TO HOW LONG CONVECTION WILL DEVELOP OVERNIGHT REMAINED,
SO 50 PERCENT SEEMED LIKE A GOOD COMPROMISE. OTHERWISE, REMAINING
CHANGES TO THE FORECAST WERE COSMETIC (MINOR).
AS FOR MARINE CONDITIONS, ELEVATED SEAS AT POHNPEI AND HIGH SURF AT
POHNPEI AND KOSRAE REMAIN A CONCERN, AS DO INUNDATION CONCERNS AT
MAJURO. WITH THAT SAID, SEAS AND SURF WILL DECREASE EARLY NEXT WEEK,
WITH LIGHT TO GENTLE WINDS PREVAILING.
WESTERN MICRONESIA
THE LATEST SATELLITE IMAGERY SHOWS PARTLY CLOUDY SKIES WITH SPOTTY
SHOWERS FOR PALAU, YAP AND CHUUK THIS AFTERNOON. ALTIMETRY SHOWS SEAS
OF 7 TO 8 FEET NEAR WENO, WITH 9 FOOT SEAS NORTH OF FANANU. SEAS OF 5
TO 7 FEET ARE SEEN NEAR PALAU AND YAP, WITH 8 FOOT SEAS A LITTLE
FARTHER NORTH.
A WEAK CIRCULATION REMAINS THE FOCUS FOR THE FORECAST ACROSS WESTERN
MICRONESIA FOR THE NEXT SEVERAL DAYS. THE CIRCULATION HAS SLOWED ITS
WESTWARD PROGRESSION A BIT AND THE MODEL GUIDANCE HAS PICKED UP ON
THIS. BASED ON GUIDANCE ALONG WITH SATELLITE TRENDS, KEPT ISOLATED
SHOWERS FOR THE EVENING AT WENO, WITH INCREASING CONVECTION MOVING IN
FROM THE EAST AS THE CIRCULATION DRIFTS WEST-NORTHWEST. THE SLOW
MOVEMENT OF THIS FEATURE LOOKS TO MAINTAIN SCATTERED SHOWERS ACROSS
WENO FOR THE NEXT FEW DAYS AS IT PROGRESSES TOWARD YAP AND PALAU. YAP
PROPER WILL SEE INCREASED CONVECTION AROUND MONDAY AS THE
CIRCULATION MOVES TOWARD THE ISLAND AND PULLS THE WEAK NEAR-
EQUATORIAL TROUGH (NET) A BIT FARTHER NORTH. AS THE SYSTEM
PROGRESSES, IT LOOKS TO SPREAD CONVECTION INTO PALAU MONDAY NIGHT.
THIS OVERALL UNSETTLED PATTERN THEN LOOKS TO CONTINUE AT YAP AND
PALAU THROUGH AT LEAST THE MIDDLE OF NEXT WEEK. FOR WENO, A DRIER
PATTERN IS EXPECTED TO MOVE INTO CHUUK AROUND MIDWEEK.
THE MARINE FORECAST IS PROGRESSING AS EXPECTED. SEAS CONTINUE TO
SLOWLY SUBSIDE, WITH THE NORTH TO NORTHEAST SWELL NOW DOWN ENOUGH
FOR SURF TO FALL BELOW HAZARDOUS LEVELS AT YAP. HOWEVER, SURF WILL
REMAIN ELEVATED, HOVERING JUST BELOW HAZARDOUS LEVELS ALONG NORTH
FACING REEFS THROUGH TONIGHT. FOR PALAU AND CHUUK, MOSTLY LIGHT TO
GENTLE WINDS ARE EXPECTED THROUGH THE COMING WEEK. AT YAP, GENTLE TO
MODERATE WINDS WILL CONTINUE THROUGH MOST OF NEXT WEEK, WITH
OCCASIONAL FRESH WINDS POSSIBLE EARLY IN THE WEEK.
GUM WATCHES/WARNINGS/ADVISORIES
GU...HIGH RIP CURRENT RISK THROUGH SUNDAY AFTERNOON FOR GUZ001.
HIGH SURF ADVISORY UNTIL 4 PM CHST SUNDAY FOR GUZ001.
MP...HIGH RIP CURRENT RISK THROUGH SUNDAY AFTERNOON FOR MPZ001>003.
HIGH SURF ADVISORY UNTIL 4 PM CHST SUNDAY FOR MPZ001>003.
MARIANAS WATERS...SMALL CRAFT ADVISORY FROM 10 PM THIS EVENING TO
5 PM CHST SUNDAY FOR PMZ151-152.
SMALL CRAFT ADVISORY UNTIL 5 PM CHST SUNDAY FOR PMZ153-154.
MARIANAS: CRUZ
EAST MICRONESIA: DOLL
WEST MICRONESIA: KLEESCHULTE
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