879
FXPQ50 PGUM 102315
AFDGUM
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TIYAN GU
915 AM CHST SAT APR 11 2026
MARIANAS SYNOPSIS
PARTLY CLOUDY SKIES AND ISOLATED SHOWERS ARE FOUND WITHIN THE
MARIANAS AND SURROUNDING COASTAL WATERS. SATELLITE SHOWS TROPICAL
STORM SINLAKU TO THE SOUTHEAST, WHICH IS EXPECTED TO APPROACH THE
MARIANAS DURING THE FIRST HALF OF NEXT WEEK. THE BUOYS ARE SHOWING
WAVE HEIGHTS OF 8 TO 11 FEET.
DISCUSSION
FOR NOW, TROPICAL STORM SINLAKU IS NEARLY STATIONARY. WE CAN'T REALLY
TELL WHEN IT WILL APPROACH THE MARIANAS UNTIL IT STARTS DOING SO. IT
COULD STILL GO SOMEWHERE ELSE, BUT MOST NWP SYSTEMS TAKE IT TOWARD
THE MARIANAS, SO THE MAIN UNCERTAINTY IS WHEN. CHUUK IS NOW AT THE
EDGE OF THE CDO WHEREAS THEY USED TO BE RIGHT UNDER IT, SO PERHAPS IT
IS STARTING TO MOVE NOW. AROUND WEDNESDAY, WEATHER CONDITIONS WILL
START TO NORMALIZE AS SINLAKU STARTS MOVING AWAY.
MARINE
COMBINED SEAS REMAIN ABOUT 8 TO 11 FEET. THESE ARE EXPECTED TO
INCREASE SLOWLY THE NEXT COUPLE OF DAYS, THEN INCREASE DRAMATICALLY
AS TROPICAL STORM SINLAKU (PROBABLY TYPHOON SINLAKU BY THEN) MAKES
ITS APPROACH. HOW HIGH COULD THEY GO? NEARSHORE WAVE PREDICTION
SYSTEM HAD A FEW VALUES APPROACHING 50 FEET. GFSWAVE AND ECMWFWAVE
HAVE PEAK VALUES A LITTLE OVER 30 FEET. THE VAST MAJORITY OF MARINERS
PROBABLY SHOULDN'T BE MESSING WITH EITHER SET.
TROPICAL SYSTEMS
TROPICAL STORM SINLAKU (04) REMAINS NEARLY STATIONARY NEAR CHUUK,
WHERE WIND GUSTS HAVE REACHED TYPHOON FORCE AT ONE OF OUR OBSERVATION
POINTS VERY NEAR THE AIRPORT. ADDITIONALLY, REPORTS WERE RELAYED TO
US THE SYSTEM CONTINUES TO SHOW INCREASED POLEWARD OUTFLOW WITH
MAXIMUM SUSTAINED WINDS HAVING INCREASED TO 70 MPH, PER THE JOINT
TYPHOON WARNING CENTER (JTWC) POSITION AS OF 5 AM CHST.
MODEL CONTINUITY CONTINUES TO INCREASE, WITH VERY LITTLE SPREAD
BETWEEN THE OPERATIONAL GFS, ECMWF, AND NBM FORECASTS. ADDITIONALLY,
THE GEFS AND ECENS ENSEMBLE MEMBERS CONTINUE TO TIGHTEN THEIR
FORECAST TRACKS, WITH THE ONLY OUTLIERS CURRENTLY BEING FROM THE AI-
ASSISTED GOOGLE DEEPMIND SOLUTIONS.
THE (JTWC) FORECAST HAS SINLAKU BECOMING A TYPHOON BY LATE MORNING
TODAY, AND THIS LOOKS VERY REASONABLE GIVEN THE SATELLITE
MORPHOLOGY. SINLAKU IS THEN EXPECTED TO TURN NORTHWEST AND INCREASE
IT'S FORWARD MOMENTUM SLIGHTLY. THE CURRENT FORECAST HAS THIS SYSTEM
CROSSING SOUTHERN GUAM AS A LOW-END CATEGORY 4 TYPHOON. GIVEN
INCREASED FORECAST CONFIDENCE AND CLOSER TEMPORAL TIMING, IT'S
CERTAINLY POSSIBLE THAT A TYPHOON WATCH WILL PROBABLY BE NEEDED
DURING THE NEXT FORECAST CYCLE OR TWO. AT THIS TIME, THE WORST
CONDITIONS APPEAR TO BE FOR GUAM AND ROTA, BUT, FORECAST REFINEMENTS
WILL CONTINUE OVER THE NEXT FEW DAYS. THERE WILL STILL BE SOME
IMPACTS FOR TINIAN AND SAIPAN AS WELL. NOW IS THE TIME TO CONTINUE
PREPARING!
FOR MORE INFORMATION PLEASE REFER TO BULLETINS FROM THE JOINT
TYPHOON WARNING CENTER UNDER WMO HEADER WTPN31 PGTW AND FROM THE
NATIONAL WEATHER SERVICE UNDER WMO HEADER WTPQ31 PGUM.
EASTERN MICRONESIA
CONVERGENCE FEEDING INTO TROPICAL STORM SINLAKU WILL MAINTAIN A
CLOUDY PICTURE FOR EASTERN MICRONESIA. MAINLY MAJURO WILL SEE
APPRECIABLE PRECIPITATION THE NEXT COUPLE OF DAYS.
WESTERN MICRONESIA
YAP AND KOROR WILL HAVE FAIRLY DRY WEATHER FOR AT LEAST THE NEXT
COUPLE OF DAYS. CHUUK IS BEING RAKED BY TROPICAL STORM SINLAKU AND
WILL HAVE A THREAT OF FLOODING TODAY, RATED CONSIDERABLE BY THE
NATIONAL WATER CENTER. THIS WILL DIMINISH AS TROPICAL STORM SINLAKU
STARTS TO MOVE AWAY TOWARD THE MARIANAS.
GUM WATCHES/WARNINGS/ADVISORIES
GU...HIGH RIP CURRENT RISK THROUGH THURSDAY AFTERNOON FOR GUZ001.
HIGH SURF ADVISORY UNTIL 6 PM CHST THURSDAY FOR GUZ001.
MP...HIGH RIP CURRENT RISK THROUGH THURSDAY AFTERNOON FOR MPZ001>003.
HIGH SURF ADVISORY UNTIL 6 PM CHST THURSDAY FOR MPZ001>003.
SMALL CRAFT ADVISORY UNTIL 6 PM CHST THURSDAY FOR MPZ001>003.
MARIANAS WATERS...SMALL CRAFT ADVISORY UNTIL 6 PM CHST THURSDAY FOR PMZ151>154.
MARIANAS: STANKO
EAST AND WEST MICRONESIA/TROPICAL: DOLL
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