834
FXPQ50 PGUM 280900
AFDGUM
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TIYAN GU
700 PM CHST SUN JUN 28 2026
MARIANAS SYNOPSIS
SATELLITE AND RADAR IMAGERY SHOW ISOLATED SHOWERS DRIFTING THROUGH
THE MARIANAS. SCATTERED SHOWERS VISIBLE TO OUR EAST AND POSSIBLY
ISOLATED THUNDERSTORMS WILL ARRIVE LATE TONIGHT FOR TINIAN AND
SAIPAN, WITH COVERAGE SHIFTING SOUTH OVERNIGHT TO COVER ALL ISLANDS
BY MONDAY. SCATTERED SHOWERS WILL REMAIN MONDAY NIGHT. BUOY AND
MODEL DATA SHOW COMBINED SEAS OF 3 TO 5 FEET FOR GUAM AND ROTA AND 4
TO 5 FEET FOR TINIAN AND SAIPAN WILL CONTINUE TO SLOWLY DIMINISH
THROUGHOUT THE WEEK.
DISCUSSION
ISOLATED SHOWERS THIS EVENING WILL BE REPLACED BY SCATTERED SHOWERS
LATE TONIGHT FOR TINIAN AND SAIPAN. ISOLATED THUNDERSTORMS WILL BE
POSSIBLE AS WIND SHEAR INCREASES OVER ALL ISLANDS AND A WEAK UPPER
LEVEL LOW MOVES OVER THE REGION. THESE SCATTERED SHOWERS AND ISOLATED
THUNDERSTORMS WILL FILL IN FOR ALL ISLANDS BY EARLY MORNING WITH
SLIGHTLY HIGHER PRECIPITATION CHANCES FOR TINIAN AND SAIPAN. MID-
LEVEL WIND SHEAR AND THE UPPER-LEVEL LOW ARE EXPECTED TO BECOME
NEGLIGIBLE BY MONDAY NIGHT, SO NO THUNDERSTORMS ARE EXPECTED.
HOWEVER, MOISTURE WILL REMAIN SUFFICIENT FOR SCATTERED SHOWERS. DRIER
AIR AND ISOLATED SHOWERS MAY RETURN TUESDAY AND WEDNESDAY BEFORE
ANOTHER BAND OF MOISTURE BRINGS MORE SCATTERED SHOWERS AROUND
THURSDAY. CURRENTLY, MODELS INDICATE JUST ISOLATED SHOWERS BY FRIDAY
AND INDEPENDENCE DAY. TEMPERATURES MAY REACH UP TO 90 ON INDEPENDENCE
DAY AHEAD OF INVEST 95W (DISCUSSED IN THE "TROPICAL SYSTEMS" SECTION
BELOW).
MARINE
COMBINED SEAS OF 3 TO 5 FEET FOR GUAM AND ROTA AND 4 TO 5 FEET FOR
TINIAN AND SAIPAN WILL CONTINUE TO SLOWLY DIMINISH TONIGHT AS BOTH
EAST AND WEST SWELLS WEAKEN. THERE WILL BE A MODERATE RISK OF RIP
CURRENTS ALONG EAST-FACING REEFS TONIGHT THROUGH MONDAY NIGHT. GENTLE
EAST WINDS WILL PREVAIL TONIGHT THROUGH EARLY THIS WEEK. SCATTERED
SHOWERS AND ISOLATED THUNDERSTORMS ARE EXPECTED AFTER MIDNIGHT FOR
TINIAN AND SAIPAN, AND THEN FOR ALL ISLANDS MONDAY. SCATTERED SHOWERS
WILL REMAIN MONDAY NIGHT. ANOTHER WAVE OF SCATTERED SHOWERS IS
POSSIBLE THURSDAY. SWELL FROM CURRENT INVEST 95W COULD START TO
BUILD INTO THE MARIANAS AS SOON AS JULY 4TH DEPENDING ON ITS
STRENGTH. THIS WILL BE MONITORED CLOSELY.
TROPICAL SYSTEMS
INVEST 95W, LOCATED NEAR THE WESTERN MARSHALL ISLANDS AT AROUND
6N166E, REMAINS A WEAK, DISORGANIZED DISTURBANCE, BUT HAS SHOWN SIGNS
OF STRENGTHENING. SATELLITE IMAGERY DEPICTS A VERY BROAD REGION OF
FLARING, DEEP CONVECTION EXTENDING INTO THE SOUTHERN PERIPHERY OF
96W, ASSOCIATED WITH A DEVELOPING WESTERLY WIND BURST NEAR THE
EQUATOR. SCATTEROMETRY FROM THIS MORNING REVEALS AN AREA OF STRONG
TO NEAR-GALE WINDS LOCATED OVER THE SOUTHERN RMI, JUST SOUTH OF
95W'S CENTER, POINTING TO FURTHER DEVELOPMENT. INVEST 95W IS NOW
RATED "MEDIUM" FOR DEVELOPMENT, MEANING IT WILL LIKELY DEVELOP INTO A
SIGNIFICANT TROPICAL CYCLONE (A TROPICAL DEPRESSION), BUT NOT WITHIN
24 HOURS. MODELS CONTINUE TO DEPICT GRADUAL STRENGTHENING OVER THE
NEXT FEW DAYS AS 95W SHIFTS NORTH ACROSS THE MARSHALL ISLANDS.
INVEST 96W, EMBEDDED WITHIN THE FAR WESTERN EDGE OF THE NEAR-
EQUATORIAL TROUGH (NET), REMAINS RATED AS A "SUB-LOW," MEANING
DEVELOPMENT IS POSSIBLE, BUT NOT EXPECTED OVER THE NEXT FEW DAYS. IT
IS LOCATED TO THE NORTH OF PALAU, CENTERED ROUGHLY AT 10N134E, AND
CONTINUES TO SUPPORT LOCALLY HEAVY SHOWERS AND ISOLATED THUNDERSTORMS
ACROSS THE REGION. CONVECTION WITHIN THE SOUTHWESTERLY MONSOON FLOW
BEHIND INVEST 96W WILL MAINTAIN AN UNSETTLED PATTERN FOR YAP AND
PALAU OVER THE NEXT FEW DAYS AS THE DISTURBANCE PULLS AWAY TO THE
NORTHWEST.
FOR MORE INFORMATION, PLEASE REFER TO BULLETINS FROM THE JOINT
TYPHOON WARNING CENTER (JTWC) UNDER WMO HEADER ABPW10 PGTW.
EASTERN MICRONESIA
THE MAIN FOCUS WAS ON MAJURO. ADDITIONAL EFFORTS WERE MADE TO TRY TO
"TIME" WIND DIRECTION CHANGES AT MAJURO REGARDING THE SYNOPTIC WINDS
ASSOCIATED WITH INVEST 95W. ADDITIONALLY, FOCUS WAS PLACED ON
RAINFALL POTENTIAL FOR THESE AREAS.
FOR POHNPEI, BEING THE FURTHEST LOCATION FROM INVEST 95W CURRENTLY,
THE FOCUS WAS ON RAINFALL POTENTIAL AND TIMING. A SIMILAR CONCERN WAS
ALSO NOTED AT KOSRAE, WITH AN ADDITIONAL FOCUS ON LATER-DEVELOPING
NORTH TO NORTHEAST SWELL POTENTIAL, AS DISCUSSED IN THE SPECIAL
WEATHER STATEMENT.
AS FOR MARINE CONDITIONS, THE WINDS WILL BE LIGHT TO MODERATE NEAR
MAJURO, BECOMING FRESH TO STRONG AT TIMES. AT KOSRAE AND POHNPEI,
LIGHT TO GENTLE WINDS CAN BE EXPECTED. SEAS OF 4 TO 6 FEET CAN BE
EXPECTED THROUGH THE PERIOD, LOCALLY HIGHER IN THE 6 TO 9 FOOT RANGE
OUTSIDE MAJURO'S COASTAL WATERS TO THE SOUTH. THIS WILL CONTINUE TO
BE MONITORED AS IT COULD AFFECT MAJURO AND POSSIBLY KOSRAE IN TIME,
BUT FOR NOW THE "BRUNT" OF THE WIND-DRIVEN HIGHER WAVES WILL BE IN
THE SOUTH CENTRAL RMI.
WESTERN MICRONESIA
A WET PATTERN IS EXPECTED FOR PALAU OVER THE NEXT FEW DAYS AS
MONSOON FLOW, WRAPPING INTO NEARBY INVEST 96W, GENERATES HEAVY
SHOWERS AND GUSTY SOUTHWEST WINDS. LATEST HIMAWARI VISIBLE SATELLITE
IMAGERY DEPICTS DRIER CONDITIONS THIS AFTERNOON WITH MOST OF THE
CONVECTION FOCUSED TO THE WEST OF PALAU, BUT MODEL AND SATELLITE
TRENDS POINT TO A BUILD-UP OF SHOWERS ACROSS THE AREA BEGINNING LATE
OVERNIGHT TONIGHT AND PEAKING MONDAY. WIDESPREAD HEAVY SHOWERS ARE
EXPECTED BY MONDAY AFTERNOON, AND LATEST ENSEMBLE GUIDANCE SUGGESTS
RAINFALL TOTALS OF 1 TO 2 INCHES THROUGH MONDAY NIGHT. LOCALLY HIGHER
AMOUNTS WILL BE POSSIBLE. AN ADDITIONAL 1 TO 1.5 INCHES WILL BE
POSSIBLE THROUGH MIDWEEK AS THE MONSOON PATTERN CONTINUES, WEAKENING
IN THE LATTER HALF OF THE WEEK AS INVEST 96W MOVES AWAY AND A COL
SHIFTS OVER THE REGION. MODELS SUGGEST THAT YAP PROPER WILL REMAIN IN
THE DRIER EAST-SOUTHEASTERLY TO EASTERLY TRADE WINDS, BUT PERIODS OF
SCATTERED SHOWERS ARE EXPECTED IN THE EARLIER HALF OF THE WEEK. TO
THE EAST, SATELLITE DEPICTS PATCHY SCATTERED SHOWERS NEAR CHUUK THIS
AFTERNOON. MODELS KEEP CHUUK IN A QUIETER DOLDRUM-LIKE PATTERN FOR
MUCH OF THE WEEK WITH A COL SET UP NEARBY, ASSOCIATED MAINLY WITH
DEVELOPING INVEST 95W OVER EASTERN MICRONESIA. CHUUK MAY SEE SLIGHTLY
WETTER CONDITIONS BY THE END OF THE WEEK AS A BROAD REGION OF WEST
TO SOUTHWEST WINDS LOOKS TO EXTEND INTO THE REGION.
BENIGN MARINE CONDITIONS CONTINUE, WITH ALTIMETRY AND YAP BUOY DATA
INDICATING COMBINED SEAS BETWEEN 3 AND 5 FEET ACROSS THE REGION.
PALAU CAN EXPECT MOST OF ITS SWELL ENERGY OUT OF THE SOUTHWEST OVER
THE NEXT FEW DAYS, ASSOCIATED WITH THE ONGOING MONSOON PATTERN. CHUUK
MAY SEE SEA HEIGHTS START TO INCREASE BY THE END OF THE WEEK,
ASSOCIATED WITH AN INCREASE IN NORTHEAST SWELL FROM DEVELOPING INVEST
95W.
GUM WATCHES/WARNINGS/ADVISORIES
GU...NONE.
MP...NONE.
MARIANAS WATERS...NONE.
MARIANAS: OGLE
EAST MICRONESIA: DOLL
WEST MICRONESIA/TROPICAL SYSTEMS: DECOU
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