322
FXPQ50 PGUM 090745
AFDGUM
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TIYAN GU
545 PM CHST SUN AUG 9 2026
MARIANAS SYNOPSIS
MODERATE TO STRONG SOUTHWESTERLIES PREVAIL ACROSS THE REGION.
SATELLITE IMAGERY AND DOPPLER RADAR INDICATE LITTLE SHOWER ACTIVITY,
WITH JUST FAST-MOVING CLOUDS IN THE NORTHERN COASTAL WATERS. BUOYS
AND RECENT ALTIMETRY PASSES INDICATE SEAS ARE 8 TO 11 FEET.
DISCUSSION
A RESURGENCE OF ANOTHER MONSOON SURGE, INDUCED BY VARIOUS FAST-
DEVELOPING SYSTEMS EMBEDDED WITHIN THE VAST MONSOON TROUGH TO THE
NORTH, IS EXPECTED TO BRING INCREASING WINDS, SHOWERS AND
THUNDERSTORMS TO THE REGION. AT THIS TIME, THE SURGE SOUTH OF A
REGENERATED TROPICAL DEPRESSION KUJIRA (14W) IS EXPECTED TO TRIP OVER
TINIAN AND SAIPAN, WITH 20-25 MPH SOUTHWESTERLIES OCCASIONALLY
GUSTING TO 35 MPH NEAR POTENTIALLY HEAVY SHOWERS MONDAY. THE LEADING
EDGE OF THESE SURGES ARE EXPECTED TO ANCHOR THEMSELVES OVER TINIAN
AND SAIPAN THROUGH MIDWEEK, AS A SECONDARY DISTURBANCE FOLLOWS AN
EASTWARD- PROPAGATING KUJIRA AND INDUCES A MUCH MORE PERSISTENT SURGE
THEREAFTER. THIS WILL ALLOW CONVECTION TO THEN SHIFT SOUTHWARD,
SPREADING ON-AND-OFF SHOWERS AND THUNDERSTORMS ACROSS THE REST OF THE
CNMI AND GUAM. HOWEVER, THESE CONDITIONS ARE NOT EXPECTED TO BE
CONDUCIVE FOR FLASH FLOODING, SO A FLOOD WATCH IS NOT YET WARRANTED
BUT MAY BE CONSIDERED FOR TINIAN AND SAIPAN THE NEXT DAY OR SO.
CONDITIONS ARE EXPECTED TO IMPROVE CONSIDERABLY IN THE SECOND HALF OF
THE WEEK ONCE THESE SYSTEMS MOVE AWAY FROM THE AREA AND A TROPICAL
RIDGE FORMS IN WESTERN MICRONESIA, INTRODUCING DRIER DIFFUSIVE FLOW
ACROSS THE MARIANAS FOR THE REST OF THE WEEK.
MARINE
COMBINED SEAS OF 8 TO 11 FEET ARE EXPECTED OVER THE NEXT FEW DAYS,
REMAINING HAZARDOUS TO SMALL CRAFT THROUGH AT LEAST EARLY TUESDAY
MORNING. SEAS LOOK TO FALL BELOW HAZARDOUS LEVELS FOR GUAM AND
ROTA BY MIDWEEK, BUT ARE EXPECTED TO REMAIN HAZARDOUS FOR TINIAN
AND SAIPAN INTO THE LATTER HALF OF THE WEEK AS THE SOUTHERN EDGE
OF THE MONSOON SURGE PERSISTS OVER THE AREA.
TROPICAL SYSTEMS
THE REMNANTS OF TROPICAL DEPRESSION 13W HAVE STRENGTHENED, AND WE NOW
HAVE TD KUJIRA AGAIN (13W) LOCATED WEST OF THE MAUG ISLANDS NEAR
21.9N 142.23E. KUJIRA IS FORECAST TO TURN EAST, INCREASE ITS FORWARD
SPEED, AND BECOME A TROPICAL STORM ONCE AGAIN BY MONDAY AFTERNOON.
NEXT ON THE LIST IS INVEST 98W, CURRENTLY 300 MILES EAST-
NORTHEAST OF THE MAUG ISLANDS, AS IT'S CURRENTLY NEAR 20N153E.
THIS DISTURBANCE IS RATED AS "MEDIUM" BY JTWC, MEANING DEVELOPMENT
OF A TROPICAL CYCLONE IS LIKELY BEYOND 24 HOURS. CONDITIONS ARE
FAVORABLE FOR BOTH THE TCFA AND 98W TO CONTINUE TO ORGANIZE, AND
THE MODELS ALSO SHOW THIS WILL OCCUR WITH 98W AS IT ALSO HEADS FOR
AN AREA NORTH OF WAKE ISLAND DURING THE NEXT FEW DAYS.
THEN WE HAVE ANOTHER CIRCULATION, DUBBED INVEST 99W, WHICH IS
LOCATED NEAR ALONG THE MONSOON TROUGH NEAR 22N166E. THIS
DISTURBANCE LACKS A TRUE LLCC PER SCATTEROMETER ANALYSIS AND
VISIBLE IMAGERY LOOPS. THIS LOOKS TO BE MORE AN ARTIFACT OF A
MONSOON VORTEX CO-LOCATED AT THE END OF A MONSOON TROUGH AND
WITHIN A FAVORABLE ENVIRONMENT, WITH NO DEVELOPMENT EXPECTED.
STILL, GIVEN SHARP BENDING IN THE STREAMLINE ANALYSIS AND SOME
LOCALIZED ELEVATED CONVECTION, THE "SUB-LOW" RATING FROM JTWC IS
WARRANTED, AND WE'LL KEEP AN EYE ON IT.
FINALLY, WE HAVE AN AREA OF CYCLONIC ROTATION THAT WE'VE BEEN
WATCHING FOR A FEW DAYS NOW, NORTHEAST OF MAJURO NEAR 10N173E. THE
CYCLONIC LOW-LEVEL FLOW AROUND THE LLCC HAS STRENGTHENED MARKEDLY
SINCE YESTERDAY, AS EVIDENT IN THE VISIBLE LOOP IMAGERY. THIS
CIRCULATION IS AT THE TAIL END MONSOON TROUGH. THE INCREASED
CYCLONIC FLOW HAS ALLOWED FOR CONVECTION TO INCREASE FROM NEAR
KOSRAE TO MAJURO, AS WESTERLY FLOW SOUTH OF THE LLCC HAS
STRENGTHENED. WITH THAT SAID, WE STILL EXPECT THIS SYSTEM TO HEAD
WEST TO THE RMI CHAIN WITH A STEADY STATE IN DEVELOPMENT, BEFORE
POSSIBLY DRIFTING WEST-SOUTHWEST TO EAST OF POHNPEI/NORTH OF
KOSRAE WHILE IT WEAKENS, WITH THIS EXPECTED TO OCCUR OVER THE NEXT
48 TO 72 HOURS. WITH THAT SAID, JTWC AND WFO GUAM CONTINUE TO
WATCH THIS FEATURE FOR POSSIBLE INVEST INCLUSION.
FOR MORE INFORMATION PLEASE REFER TO BULLETINS FROM THE JOINT
TYPHOON WARNING CENTER UNDER WMO HEADER ABPW10 PGTW.
EASTERN MICRONESIA
SHOWERS HAVE DEVELOPED ACROSS BETWEEN POHNPEI AND THE RMI CHAIR TO
INCLUDE KOSRAE, WHERE A FEW SHOWERS IN THAT VICINITY ARE OF MODERATE
INTENSITY, AS EVIDENT BY -60 DEG. C CLOUD TOP TEMPERATURES.
OTHERWISE, ANY RAINFALL HAS BEEN LIFT, WITH THE MOISTURE SURGE (THAT
WE TALKED ABOUT THE PAST COUPLE OF DAYS), AS EVIDENT BY PWATS
(PRECIPITABLE WATER VALUES NEAR OR ABOVE 2.5 INCHES AREA-WIDE.
HOWEVER, DIVERGENCE IS WEAK, ALLOWING FOR MAINLY MID TO HIGH LEVEL
CLOUD COVER AND LIGHT SHOWERS TO PERSIST. PERHAPS, WE'LL SEE ANOTHER
NOCTURNAL (NIGHTTIME) FLARE-UP LATER TONIGHT. STILL, GIVEN HOW MIST
THE ATMOSPHERE HAS BECOME, CARRIED SCATTERED TO NUMEROUS SHOWERS AT
KOSRAE, AND SCATTERED SHOWERS ELSEWHERE. ADDITIONAL DISTURBANCES LOOK
TO KEEP THE WEATHER UNSETTLED OVER THE NEXT SEVERAL DAYS, AS THEY
CROSS THE DATE LINE AND HEAD WEST.
WESTERN MICRONESIA
SATELLITE IMAGERY SHOWS MOSTLY CLEAR TO PARTLY CLOUDY SKIES ACROSS
WESTERN MICRONESIA. ALTIMETRY SHOWS COMBINED SEAS OF 4 TO 7 FEET
ACROSS THE REGION.
THE DOMINANT SURFACE RIDGE THAT HAS KEPT WESTERN MICRONESIA DRY OVER
THE LAST WEEK WILL CONTINUE TO SUPPRESS CONVECTION THROUGH TONIGHT
BEFORE SHIFTING WEST THROUGH THE FIRST HALF OF THE WEEK. THIS WILL
ALLOW FOR SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS TO RETURN TO
CHUUK AS CONVERGENT SURFACE WINDS MOVE INTO THE REGION. THE DOMINANT
HIGH PRESSURE WILL CONTINUE TO SUPPRESS CONVECTION THROUGH THE WEEK
ACROSS PALAU AND YAP. A PATTERN CHANGE WILL BE POSSIBLE LATE NEXT
WEEK AND INTO THE WEEKEND AS THE MONSOON SHIFTS WESTWARD ACROSS
WESTERN MICRONESIA.
BENIGN MARINE CONDITIONS ARE EXPECTED THROUGH THE PERIOD. COMBINED
SEAS ARE CURRENTLY BETWEEN 5 AND 7 FEET. SEAS WILL GENERALLY FALL 1
TO 2 FEET OVER THE COMING DAYS. SWELLS HAVE DIMINISHED ACROSS NORTH
FACING REEFS OF YAP AND THE HIGH SURF ADVISORY WAS CANCELLED THIS
AFTERNOON.
GUM WATCHES/WARNINGS/ADVISORIES
GU...HIGH RIP CURRENT RISK THROUGH THURSDAY AFTERNOON FOR GUZ001.
HIGH SURF ADVISORY UNTIL 4 PM CHST THURSDAY FOR GUZ001.
MP...HIGH RIP CURRENT RISK THROUGH THURSDAY AFTERNOON FOR MPZ001>003.
HIGH SURF ADVISORY UNTIL 4 PM CHST THURSDAY FOR MPZ001>003.
MARIANAS WATERS...SMALL CRAFT ADVISORY UNTIL 5 AM CHST TUESDAY FOR PMZ151-152.
SMALL CRAFT ADVISORY UNTIL 5 PM CHST THURSDAY FOR PMZ153-154.
MARIANAS: MONTVILA
EAST MICRONESIA: DOLL
WEST MICRONESIA: WILLIAMS
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