760
FXPQ50 PGUM 070853
AFDGUM
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TIYAN GU
653 PM CHST FRI AUG 7 2026
MARIANAS SYNOPSIS
A MONSOON-DRIVEN SQUALL LINE LINGERED NEAR THE REGION, PRODUCING
NUMEROUS TO WIDESPREAD SHOWERS AND SCATTERED THUNDERSTORMS WEST OF
COASTAL WATERS. IT IS SLOWLY STRETCHING EASTWARD ACROSS ROTA THIS
AFTERNOON. THIS ACTIVE SEGMENT OF THE MONSOON PATTERN IS GENERATING
WIDESPREAD CLOUDINESS AND SCATTERED SHOWERS TO THE REST OF THE
REGION. ALTIMETRY AND TANAPAG BUOY DATA REVEAL COMBINED SEAS OF 9 TO
11 FEET, WITH THE PRIMARY SWELL ENERGY FROM THE WEST.
DISCUSSION
A MONSOON TROUGH EXTENDS SOUTHEASTWARD FROM TYPHOON DOLPHIN TO A
POORLY-DEFINED MONSOON DISTURBANCE, NEWLY DESIGNATED INVEST 98W, NEAR
THE FAR NORTH MARIANAS. THE MONSOON TROUGH THEN CURVES NORTHEAST
TOWARDS TROPICAL STORM CHAN-HOM (PREVIOUSLY INVEST 96W) TO THE
DISTANT NORTHEAST. AN UNSETTLED MONSOON PATTERN DIPS SOUTH ACROSS THE
CNMI. A STRONG, SQUALL LINE-LIKE FEATURE PRODUCED AN AREA OF
NUMEROUS TO WIDESPREAD SHOWERS AND SCATTERED THUNDERSTORMS WEST OF
COASTAL WATERS EARLIER TODAY, THEN GRADUALLY STRETCHED EASTWARD
ACROSS ROTA THIS AFTERNOON. SATELLITE TRENDS INDICATED NUMEROUS
LOCALLY HEAVY SHOWERS AND ISOLATED THUNDERSTORMS TRAINING ACROSS
ROTA, PRODUCING MINOR FLOODING LATE THIS AFTERNOON AND INTO THE
EVENING. MODEL GUIDANCE SHOWS THIS FEATURE SHIFTING NORTH, FOLLOWING
A TILT IN THE MONSOON TROUGH. THIS IS EXPECTED TO BRING NUMEROUS
SHOWERS TO TINIAN AND SAIPAN LATER THIS EVENING, CAPABLE OF PRODUCING
OCCASIONAL GUSTS TO 35 MPH, AND TREND DOWN TO SCATTERED SHOWERS WITH
ISOLATED THUNDERSTORMS AFTER MIDNIGHT. SEVERAL MONSOON DISTURBANCE
LINGER NEAR THE FAR NORTHERN MARIANAS, THIS UPCOMING WEEK KEEPING A
WETTER PATTERN NEARBY, HOWEVER, THERE MAY BE SOME LULLS IN THE ACTIVE
WEATHER PATTERN DEPENDING HOW CONVECTION ORGANIZES AROUND THESE
MONSOON DISTURBANCES. SOME UNCERTAINTY REMAINS SINCE THIS IS TIED TO
THE ACTUAL LOCATION AND INTENSITY OF THE MONSOON DISTURBANCES IN THE
COMING DAYS.
MARINE/SURF
A SMALL CRAFT ADVISORY REMAINS IN EFFECT THROUGH SUNDAY NIGHT. A HIGH
SURF ADVISORY REMAINS IN EFFECT ALONG WEST AND NORTH FACING REEFS
THROUGH MONDAY AFTERNOON AND A HIGH RISK OF RIP CURRENTS CONTINUES
ALONG WEST, NORTH, AND EAST FACING REEFS THROUGH MONDAY AFTERNOON.
MODERATE TO STRONG WESTERLIES PREVAIL ACROSS THE MARIANAS OVER THE
WEEKEND AS ANOTHER RESURGENCE IN THE MONSOON BUILDS, LIKELY TO
MAINTAIN MODERATE TO STRONG WINDS THROUGH THE MIDDLE OF NEXT WEEK.
COMBINED SEAS OF 8 TO 11 FEET ARE EXPECTED OVER THE NEXT FEW DAYS,
REMAINING HAZARDOUS TO SMALL CRAFT THROUGH AT LEAST EARLY NEXT WEEK.
HAZARDOUS SURF IS EXPECTED TO CONTINUE ALONG WEST AND NORTH FACING
REEFS OF THE MARIANAS THROUGH MONDAY, IN ADDITION TO THE HIGH RIP
CURRENT RISK ALONG WEST, NORTH, AND EAST FACING REEFS. RIP CURRENT
RISK MAY DROP TO MODERATE ALONG EAST REEFS OVER THE WEEKEND AS
NORTHWESTERLY AND EASTERLY SWELLS DECREASE.
TROPICAL SYSTEMS
THE ONLY SYSTEM THAT'S CURRENTLY IN GUAM'S AOR (AREA OF
RESPONSIBILITY) IS INVEST 98W. THIS IS A NEWLY-FORMED INVEST, DUBBED
98W FROM JTWC (THE JOINT TYPHOON WARNING CENTER) NEAR MAUG ISLAND IN
THE FAR NORTHERN CNMI. THE LLCC (LOW- LEVEL CIRCULATION CENTER IS
ONLY VISIBLE WHEN VIEWING AN IN- HOUSE SCATTEROMETER DATA PROGRAM
THAT COMBINED THREE DIFFERENT TYPES OF SCATTEROMETER DATA, BUT IT'S
THERE. THE LLCC IS FAIRLY CLOSE TO 19N144E, BUT VISIBLE IMAGER SHOWS
A BETTER CYCLONIC CIRCULATION THAT'S SLIGHTLY ELEVATED CLOSER TO
19.1N 143.4E. THIS CIRCULATION HAS FORMED IN THE SADDLE OF A TROUGH
THAT ENTERS GUAM'S AOR NEAR IWO TO, STRETCHES SOUTHEAST TO 98W IN A
SADDLE SHAPE (BOWING CURVED BOTTOM), BEFORE TURNING NORTHEAST AND
CONNECTING WITH NEWLY- FORMED TD CHAN-HOM (14W), WHICH IS LOCATED
WELL NORTH OF WAKE ISLAND AND OUT OF GUAM'S AOR. WHERE 98W HAS
FORMED, IT'S ALSO AT THE TAIL- END OF A RIDGE AXIS THAT STRETCHES
NORTHWARD, AND CO-LOCATED IN A COL BETWEEN THE TWO MORE-DEVELOPED
TROPICAL SYSTEMS OF TYPHOON DOLPHIN (WELL OUTSIDE OF GUAM'S AOR NEAR
OKINAWA), AND CHAN-HOM.
98W IS IN A FAVORABLE ENVIRONMENT CHARACTERIZED BY WARM SSTS (SEA
SURFACE TEMPERATURES) AND LOW WIND SHEAR. THE ECENS IS WAY MORE "HOT
AND HEAVY" (FASTER/STRONGER) THAN THE GEFS IN THE DEVELOPMENT OF 98W,
BUT IN GENERAL THEY SHOW A DEVELOPING TROPICAL CYCLONE EAST OF THE
MARIANAS AND HEADING TOWARDS WAKE ISLAND IN ABOUT 2 TO 4 DAYS.
THEN, QUICKLY MOVING IN ON ITS HEELS, ARE THE REMNANTS OF TD KUJIRA
(13W), WHICH HAS HAS EXITED LUZON AND LOOKS TO ENTER GUAM'S AOR IN 24
HOURS. THE VISIBLE IMAGERY SUGGESTS THE LLCC HAS BEEN TORN APART.
HOWEVER, SIMILAR TO 98W, THE ECENS IS WAY MORE AGGRESSIVE/FASTER IN
REDEVELOPING A LLCC WITH FORMING IN 18-24 HOURS NEAR THE NORTHERN-
MOST CNMI. MEANWHILE, THE GEFS WAITS UNTIL IT'S EXITED THE ISLAND
CHAIN TO THE EAST, DEVELOPING IT MORE SLOWLY AS IT HEADS TOWARDS WAKE
ISLAND.
EASTERN MICRONESIA
THE LIGHT GENTLE WINDS AND FAIR SKIES CONTINUE AT POHNPEI AND KOSRAE
(ALTHOUGH KOSRAE HAD IT'S DAILY BUILD-UP NEAR THE MOUNTAINS, WHILE
THE COASTAL DRIVE WAS MORE CLOUD FREE. AT MAJURO HOWEVER, A SIGN OF
THINGS TO COME IS PRESENT THERE, AS INCREASED MOISTENING AND AN
EMBEDDED DISTURBANCE CROSSING THE DATE LINE HAS LEAD TO OVERCAST
SKIES. HOWEVER, THE CLOUDY (OVERCAST) SKIES DIDN'T PREVENT MAJURO
FROM TOPPING OUT AT 89 DEGREES, 2 DEGREES COOLER THAN YESTERDAY
(WE'LL TAKE IT!).
LOOKING AHEAD THROUGH THE WEEKEND AND INTO THE FIRST HALF OF NEXT
WEEK, AS THE DATE LINE DISTURBANCE HEADS WEST, IT'LL DRAG THE
MOISTURE WESTWARD TOWARDS POHNPEI AND KOSRAE, DAMPENING-OUT (DRYING
OUT SLIGHTLY). FEAR NOT THOUGH, AS A SERIES OF DISTURBANCE CENTERED
BETWEEN ~3N AND 10N HEAD WEST TO CROSS THE DATE LINE THROUGH THE
MIDDLE OF NEXT WEEK (AND PROBABLY LONGER). AS THIS OCCURS, THE
MONSOON TROUGH WILL RETREAT WEST, WITH THE TAIL END SETTLING SOUTH TO
NEAR KOSRAE (MAYBE JUST NORTH), WHILE EXTENDING EASTWARD TO THE DATE
LINE AS A NEAR-EQUATORIAL TROUGH. THIS ALL POINTS TO INCREASING
RAINFALL POTENTIAL BUILDING WEST WITH TIME, ESPECIALLY FOR THE FIRST
HALF OF NEXT WEEK.
AS FOR MARINE CONDITIONS, MARINERS CAN EXPECT LIGHT TO GENTLE WINDS
AND SEAS OF 5 TO 7 FEET TO PERSIST THROUGH THE MIDDLE OF NEXT WEEK.
WESTERN MICRONESIA
A SUBTROPICAL RIDGE ANCHORED JUST NORTH OF THE EQUATOR, IS EXPECTED
TO CONTINUE TO BRING A MOSTLY DRY SPELL TO WESTERN MICRONESIA THROUGH
AT LEAST THE FIRST HALF OF NEXT WEEK. HOWEVER, THE RIDGE IS LIKELY TO
BEGIN DISINTEGRATING ALONG THE EASTERNMOST EDGES DURING THE WEEKEND,
ALLOWING A LARGELY DISORGANIZED TROPICAL DISTURBANCE TO FORM IN
EASTERN MICRONESIA. THIS WILL BRING LOW-END SCATTERED SHOWERS AND
A THUNDERSTORM OR TWO TO CHUUK BY AROUND MIDWEEK.
COMBINED SEAS OF 6 TO 8 FEET NEAR PALAU AND YAP, AND 6 TO 7 FEET NEAR
CHUUK, ARE EXPECTED TO SLOWLY DIMINISH OVER THE NEXT SEVERAL DAYS AS
LONG-PERIOD NORTHERLY SWELLS FROM DISTANT TYPHOON DOLPHIN AND
SECONDARY SOUTHWESTERLY MONSOON SWELLS DECREASE. IN THE MEANTIME,
THE AFOREMENTIONED LONG-PERIOD SWELLS ARE STILL EXPECTED TO BRING
HAZARDOUS SURF ALONG NORTH-FACING REEFS OF YAP THROUGH MUCH OF THE
WEEKEND. AS SWELLS DIMINISH, SURF IS EXPECTED TO SUBSIDE BELOW
HAZARDOUS LEVELS OF 9 FEET AS EARLY AS SUNDAY NIGHT.
GUM WATCHES/WARNINGS/ADVISORIES
GU...HIGH RIP CURRENT RISK THROUGH MONDAY AFTERNOON FOR GUZ001.
HIGH SURF ADVISORY UNTIL 4 PM CHST MONDAY FOR GUZ001.
MP...HIGH RIP CURRENT RISK THROUGH MONDAY AFTERNOON FOR MPZ001>003.
HIGH SURF ADVISORY UNTIL 4 PM CHST MONDAY FOR MPZ001>003.
MARIANAS WATERS...SMALL CRAFT ADVISORY UNTIL 5 AM CHST MONDAY FOR PMZ151>154.
MARIANAS: CRUZ
EAST MICRONESIA/TROPICAL: DOLL
WEST MICRONESIA: MONTVILA
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