566
FXPQ50 PGUM 091058
AFDGUM
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TIYAN GU
858 PM CHST THU APR 9 2026
MARIANAS SYNOPSIS
PARTLY CLOUDY SKIES WITH SPOTTY SHOWERS AND FRESH TO STRONG TRADE
WINDS ARE SEEN ACROSS THE MARIANAS THIS EVENING. TROPICAL DEPRESSION
(TD) 04W IS SEEN TO THE SOUTHEAST OF GUAM. SEAS OF 10 FEET ARE SEEN
MAINLY OVER THE EASTERN COASTAL WATERS. ALTIMETRY SHOWS SEAS OF 6 TO
8 FEET WEST OF THE ISLANDS, WITH 10 TO 12 FEET SEEN EAST OF THE
COASTAL WATERS.
DISCUSSION
A FAIRLY CALM AND DRY PATTERN IS CURRENTLY IN PLACE ACROSS THE
MARIANAS. THIS LOOKS TO CHANGE OVER THE COMING DAYS AS TD 04W
APPROACHES THE REGION. LATEST FORECAST TRACK HAS 04W PASSING JUST
SOUTH OF GUAM MONDAY NIGHT INTO TUESDAY. AS 04W APPROACHES,
CONVECTION WILL INCREASE ACROSS THE ISLANDS. SHOWERS WILL BEGIN TO
INCREASE FOR GUAM AND ROTA SATURDAY NIGHT AND AT TINIAN AND SAIPAN
SUNDAY. THE LATEST FORECAST TRACK HAS 04W PASSING THROUGH MONDAY
NIGHT INTO TUESDAY AS A POSSIBLE CATEGORY 4 TYPHOON. BASED ON THIS
TRACK AND STRENGTH, TROPICAL STORM FORCE WINDS ARE LIKELY ACROSS
GUAM AND FAR NORTH AS ROTA AS EARLY AS MONDAY AFTERNOON, WITH
TYPHOON CONDITIONS POSSIBLE EARLY TUESDAY MORNING. TROPICAL STORM
CONDITIONS ARE ALSO POSSIBLE EARLY TUESDAY MORNING FOR TINIAN AND
SAIPAN. TD 04W IS EXPECTED TO MAINTAIN A VERY WET PATTERN ACROSS THE
REGION THROUGH THE MIDDLE OF NEXT WEEK, WITH GUAM AND ROTA LIKELY
SEEING THE HEAVIEST RAINFALL. WE WILL CONTINUE TO MONITOR THIS
SITUATION CLOSELY OVER THE NEXT FEW DAYS FOR ANY CHANGES TO THE
EXPECTED CONDITIONS. RESIDENTS OF THE MARIANAS SHOULD MONITOR
FORECASTS CLOSELY OVER THE NEXT SEVERAL DAYS AND PAY HEED TO ANY
INSTRUCTION FROM YOUR EMERGENCY MANAGERS.
MARINE/SURF
FRESH TO STRONG NORTHEASTERLIES ARE EXPECTED TO CONTINUE INTO THE
WEEKEND AS TROPICAL DEPRESSION 04W APPROACHES THE REGION. WINDS
WILL BE STRONGER OVER GUAM AND ROTA, WITH WEAKER WINDS OVER TINIAN
AND SAIPAN, AS 04W PASSES SOUTH OF GUAM EARLY NEXT WEEK. TROPICAL
STORM FORCE WINDS ARE POSSIBLE EARLY NEXT WEEK FOR TINIAN AND
SAIPAN, WITH TYPHOON FORCE WINDS POSSIBLE FOR GUAM AND ROTA.
SHOWER INTENSITY IS EXPECTED TO INCREASE SIGNIFICANTLY LATE THIS
WEEKEND, WITH THE HEAVIEST SHOWERS EXPECTED EARLY NEXT WEEK.
COMBINED SEAS OF 8 TO 10 FEET ARE EXPECTED TO BUILD OVER THE NEXT
FEW DAYS DUE TO INCREASING TRADE SWELL AND WIND WAVES AS TD 04W
STRENGTHENS. SEAS WILL BE HIGHER FOR GUAM AND ROTA.
THERE IS A HIGH RISK OF RIP CURRENTS ALONG EAST FACING REEFS THROUGH
AT LEAST SUNDAY. SURF COULD BECOME HAZARDOUS ALONG NORTH, EAST AND
SOUTH FACING REEFS AS EARLY AS FRIDAY NIGHT, WITH DANGEROUS SURF
POSSIBLE OVER THE WEEKEND INTO NEXT WEEK AS STRENGTHENING TROPICAL
DEPRESSION 04W MOVES TOWARD THE MARIANAS. SURF WILL REMAIN MODERATE
ALONG WEST FACING REEFS THROUGH THE WEEKEND. THERE WILL BE A MODERATE
RISK OF LIGHTNING BEGINNING SATURDAY NIGHT.
HYDROLOGY
A VERY WET PATTERN IS EXPECTED TO MOVE INTO THE MARIANAS OVER THE
WEEKEND INTO NEXT WEEK. AS TD 04W APPROACHES THE REGION, SHOWERS AND
THUNDERSTORMS WILL INCREASE, WITH HEAVY RAINFALL EXPECTED TO BEGIN
AROUND SUNDAY NIGHT AND CONTINUING INTO TUESDAY NIGHT OR WEDNESDAY.
ROTA AND GUAM LOOK TO SEE THE GREATEST RAINFALL, WITH TOTALS OF 10 TO
15 INCHES, WITH LOCALLY HEAVIER RAINFALL POSSIBLE, SUNDAY THROUGH
TUESDAY. THIS AMOUNT OF RAIN WILL LIKELY PRODUCE SOME FLASH FLOODING
ACROSS GUAM AND POSSIBLY ROTA. A HYDROLOGIC STATEMENT WILL BE ISSUED
SHORTLY. NOW IS THE TIME TO CLEAR ANY DRAINAGE AREAS OF DEBRIS TO
MINIMIZE FLOODING POTENTIAL.
TINIAN AND SAIPAN CAN EXPECT LOWER RAINFALL TOTALS, THOUGH AMOUNTS
OF 6 TO 8 INCHES ARE POSSIBLE. THIS AMOUNT OF RAINFALL IS NOT
EXPECTED TO PRODUCE FLASH FLOODING, HOWEVER, URBAN AND NUISANCE
FLOODING IS POSSIBLE.
TROPICAL SYSTEMS
INVEST 90W STRENGTHENED INTO TD 04W EARLY THIS AFTERNOON. 04W IS
CURRENTLY SEEN NEAR 8N152E, MOVING SLOWLY WEST. LATEST SATELLITE
DATA SHOWS DEEP CONVECTION TO THE WEST OF THE CENTER. 04W IS BECOMING
MORE ORGANIZED AND STRENGTHENING FASTER THAN PREVIOUSLY ANTICIPATED.
A TROPICAL STORM WATCH WAS ISSUED EARLIER FOR FANANU AND ULUL IN
CHUUK STATE. THE LATEST FORECAST INTENSIFICATION AND MOVEMENT HAS
RESULTED IN THESE WATCHES BEING UPGRADED TO TROPICAL STORM WARNINGS,
WITH A TYPHOON WATCH FOR ULUL. A TROPICAL STORM WATCH IS ALSO BEING
ISSUED FOR WENO, CHUUK. THE LATEST FORECAST TRACK SHOWS 04W PASSING
SOUTH OF GUAM EARLY TUESDAY MORNING AS A CATEGORY 4 TYPHOON. BASED ON
THIS PATH AND INTENSITY, TROPICAL STORM FORCE WINDS ARE LIKELY FOR
GUAM AND ROTA AS EARLY AS MONDAY AFTERNOON, WITH TYPHOON CONDITIONS
POSSIBLE AS EARLY AS TUESDAY MORNING. TINIAN AND SAIPAN COULD SEE
TROPICAL STORM CONDITIONS LATE MONDAY NIGHT. RESIDENTS OF FANANU,
ULUL AND WENO IN CHUUK STATE; AND THE MARIANAS SHOULD MONITOR
FORECASTS CLOSELY OVER THE NEXT FEW DAYS. NOW IS THE TIME TO PREPARE
FOR TROPICAL STORM TO TYPHOON CONDITIONS EARLY NEXT WEEK, DON'T WAIT
UNTIL THE LAST MINUTE. FOR MORE INFORMATION ON TD 04W, SEE BULLETINS
ISSUED BY THE JOINT TYPHOON WARNING CENTER UNDER WMO HEADER WTPN31
PGTW, AND BY THE NATIONAL WEATHER SERVICE UNDER WMO HEADERS WTPQ31
PGUM AND WTPQ81 PGUM.
EASTERN MICRONESIA
THE TROPICAL DISTURBANCE, INVEST 90W, THAT HAS BROUGHT NUMEROUS
HEAVY SHOWERS AND ISOLATED THUNDERSTORMS OVER THE LAST SEVERAL DAYS
TO POHNPEI STATE AND KOSRAE HAS STRENGTHENED TO A TROPICAL
DEPRESSION, 04W, CENTERED AROUND 8.7N 152.1E THIS AFTERNOON. THE
DEPRESSION IS FORECAST TO MOVE WEST-NORTHWEST AROUND 5 KNOTS DURING
THE NEXT COUPLE OF DAYS WHILE IT CONTINUES TO STRENGTHEN. CONVECTION
ASSOCIATED WITH 04W AND TROUGHING JUST TO THE SOUTHEAST IS PROMOTING
SCATTERED TO NUMEROUS HEAVY SHOWERS AND ISOLATED THUNDERSTORMS ACROSS
POHNPEI STATE AND KOSRAE THIS AFTERNOON. SCATTERED TO LOW-END
NUMEROUS HEAVY SHOWERS WILL LIKELY PERSIST THROUGH TONIGHT, WITH
CONDITIONS IMPROVING SLIGHTLY ON FRIDAY AS 04W LIFTS MORE NORTHWARD.
WEAK TRADE-WIND TROUGHS ARE FORECAST TO MOVE WESTWARD THROUGH THE
PERIOD AND WILL LIKELY KEEP ELEVATED SHOWER AND ISOLATED THUNDERSTORM
CHANCES THROUGH AT LEAST SATURDAY ACROSS EASTERN MICRONESIA,
PARTICULARLY ACROSS THE MARSHALL ISLANDS. GENTLE TO MODERATE
SOUTHEAST WINDS WILL CONTINUE FOR POHNPEI AND KOSRAE THROUGH FRIDAY
AND BECOME MOSTLY GENTLE THROUGHOUT THE DAY ON SATURDAY. THOUGH,
PERIODS OF MODERATE WINDS WILL STILL BE POSSIBLE AT POHNPEI THROUGH
THE WEEKEND. MOSTLY GENTLE EAST WINDS ARE EXPECTED TO PERSIST AT
MAJURO.
A DIMINISHING EASTERLY SWELL AND A LINGERING, SMALL NORTH TO
NORTHEAST SWELL WILL PERSIST THROUGHOUT THE WATERS OVER THE NEXT 12
HOURS OR SO, BEFORE A NORTHEAST SWELL AND SMALL SOUTHEAST SWELL
BUILD IN STARTING ON FRIDAY. THE HIGH SURF ADVISORY WAS EXTENDED
ANOTHER 12 HOURS, THROUGH 3 AM TONIGHT, FOR EAST-FACING REEFS OF
KOSRAE AND SURF IS EXPECTED TO FALL BELOW HAZARDOUS LEVELS OF 8 FEET
THEREAFTER. SURF WILL REMAIN ELEVATED ALONG NORTH-FACING REEFS AT
KOSRAE AND EAST-FACING REEFS AT POHNPEI THROUGH TONIGHT. THE SMALL
CRAFT ADVISORY FOR POHNPEI WAS ALLOWED TO EXPIRE THIS AFTERNOON AS
SEAS CONTINUE TO DIMINISH. COMBINED SEAS WILL SLOWLY FALL THROUGH
THE WEEKEND, EVENTUALLY BECOMING 4 TO 7 FEET AT ALL SITES BY EARLY
MONDAY WITH SEAS AROUND POHNPEI BEING THE SLOWEST TO SUBSIDE.
WESTERN MICRONESIA
SATELLITE IMAGERY SHOWS TROPICAL DEPRESSION 04W NORTH OF WENO SLOWLY
DRIFTING WESTWARD, BRINGING WIDESPREAD SHOWERS AND ISOLATED
THUNDERSTORMS. COMBINED SEAS OF 6 TO 8 FEET ARE OCCURRING ACROSS
PALAU AND YAP, AND SEAS OF 8 TO 10 FEET ARE SEEN ACROSS CHUUK.
SIGNIFICANT CHANGES HAVE BEEN MADE TO THE WESTERN MICRONESIA
FORECAST. FORMER INVEST 90W WAS UPGRADED TO TROPICAL DEPRESSION 04W
BY THE JTWC. TD 04W IS CURRENTLY LOCATED JUST NORTH OF CHUUK NEAR
8.1N AND 151.9E. THIS IS THE MAIN WEATHER FEATURE FOR WESTERN
MICRONESIA AS SURFACE DIVERGENCE KEEPS YAP AND PALAU DRY THROUGH THE
WEEKEND. WENO IS CURRENTLY IN A DRY SLOT, BUT WIDESPREAD SHOWERS AND
ISOLATED THUNDERSTORMS ARE EXPECTED TO BUILD IN ACROSS CHUUK TONIGHT
AS THE BAND OF CONVERGENCE SETS UP OVER THEM.
MARINE CONDITIONS WILL BE DANGEROUS ACROSS CHUUK OVER THE NEXT
COUPLE OF DAYS AS TD 04W IS FORECASTED TO INTENSIFY INTO A TROPICAL
STORM TONIGHT AND A TYPHOON ON SATURDAY. HAZARDOUS TO DANGEROUS SEA
CONDITIONS WILL BE POSSIBLE ACROSS YAP EARLY NEXT WEEK AS TD04W
LIFTS JUST NORTH OF THEM. DEPENDING ON THE LOCATION OF THE STORM, A
HAZARDOUS SEAS WATCH MAY BE NECESSARY FOR YAP BY SATURDAY'S FORECAST
PACKAGE.
GUM WATCHES/WARNINGS/ADVISORIES
GU...HIGH RIP CURRENT RISK THROUGH SUNDAY AFTERNOON FOR GUZ001.
MP...HIGH RIP CURRENT RISK THROUGH SUNDAY AFTERNOON FOR MPZ001>003.
MARIANAS WATERS...SMALL CRAFT ADVISORY UNTIL 6 PM CHST SUNDAY FOR
PMZ151>154.
MARIANAS: KLEESCHULTE
EAST MICRONESIA: WHISNANT
WEST MICRONESIA: WILLIAMS
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page