780
FXPQ50 PGUM 100710
AFDGUM
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TIYAN GU
510 PM CHST SUN AUG 10 2025
MARIANAS SYNOPSIS
LATEST SATELLITE AND RADAR SHOWS MOSTLY CLOUDY SKIES WITH SCATTERED
SHOWERS AND ISOLATED THUNDERSTORMS ACROSS THE CNMI. MOSTLY CLOUDY
SKIES WITH ISOLATED SHOWERS ARE SEEN OVER GUAM. BUOYS SHOW SEAS
BETWEEN 2 AND 4 FEET, WHILE ALTIMETRY SHOWS SEAS OF 3 TO 5 FEET OVER
THE EASTERN WATERS.
DISCUSSION
UPPER-LEVEL DIVERGENCE ASSOCIATED WITH THE TUTT (TROPICAL UPPER
TROPOSPHERIC TROUGH) MOVED OVER THE MARIANAS, BRINGING SCATTERED
SHOWERS AND ISOLATED THUNDERSTORMS TO THE CNMI TODAY AND TONIGHT.
THIS CONVECTION IS EXPECTED TO SPREAD SOUTH AS THE TUTT DRIFTS WEST-
SOUTHWEST THROUGH THE NEXT COUPLE OF DAYS. SCATTERED SHOWERS LOOK TO
CONTINUE FOR THE CNMI THROUGH MONDAY AFTERNOON AND SHOULD SPREAD
SOUTH OVER GUAM BY MONDAY MORNING. THE TUTT WILL SLOWLY MOVE THROUGH
THE REGION, ALLOWING SHOWERS TO DECREASE TO ISOLATED MONDAY NIGHT,
THOUGH THUNDERSTORMS WILL REMAIN A POSSIBILITY THROUGH TUESDAY. FOR
GUAM, LIGHT AND VARIABLE WINDS TUESDAY AND WEDNESDAY WILL BRING
RESULT IN ISLAND CONVECTION DURING THE AFTERNOON ON BOTH DAYS, AND
COULD OCCUR AGAIN ON THURSDAY. OTHERWISE, A DRY TRADE-WIND PATTERN
IS EXPECTED TUESDAY NIGHT THROUGH THE WEEKEND.
MARINE
LIGHT TO GENTLE WINDS ARE EXPECTED THROUGH NEXT WEEK. COMBINED SEAS
OF 3 TO 5 FEET WILL SLOWLY SUBSIDE, DROPPING TO BETWEEN 2 AND 3 FEET
BY THURSDAY. AN UPPER-LEVEL LOW WILL PRODUCE ISOLATED THUNDERSTORMS
THROUGH TUESDAY.
TROPICAL SYSTEMS
AT 1:00 PM, TROPICAL STORM PODUL (16W) WAS CENTERED SOUTH-SOUTHWEST
OF IWO TO NEAR 22N138E. PODUL IS MOVING WEST ACROSS THE PHILIPPINE
SEA AT 16 MPH. PODUL IS EXPECTED TO MAINTAIN THIS COURSE WITH A
DECREASE IN FORWARD SPEED. MAXIMUM SUSTAINED WINDS ARE 65 MPH. PODUL
IS STILL EXPECTED TO SLOWLY STRENGTHEN, THOUGH IT IS NOT EXPECTED TO
BECOME A TYPHOON UNTIL MONDAY NIGHT OR TUESDAY. FOR MORE INFORMATION
ON PODUL, PLEASE REFER TO BULLETINS FROM THE JOINT TYPHOON WARNING
CENTER UNDER WMO HEADER WTPN32 PGTW AND FROM THE NATIONAL WEATHER
SERVICE UNDER WMO HEADER WTPQ32 PGUM.
EASTERN MICRONESIA
AN ACTIVE, BUT FRAGMENTED INTERTROPICAL CONVERGENCE ZONE (ITCZ)
STRETCHES ACROSS THE REGION. THE BULK OF CONVECTION IS FOCUSED AROUND
A BROAD TRADE-WIND TROUGH WITHIN THE OVERALL ITCZ PATTERN, EXTENDING
THROUGH MUCH OF KOSRAE STATE TO THE NORTHERN MARSHALLS. NUMEROUS
SHOWERS AND ISOLATED THUNDERSTORMS ARE EXPECTED FOR KOSRAE THROUGH
TONIGHT, MEANWHILE MAJURO IS SLIGHTLY EAST OF THE TROUGH AXIS,
ALTHOUGH SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS ARE STILL
EXPECTED, WITH BOTH LOCATIONS SEEING OCCASIONAL GUSTS TO 20 KT NEAR
HEAVIER SHOWERS THROUGH TONIGHT. PATCHIER SHOWERS ARE SEEN AHEAD OF
THIS FEATURE, NEAR POHNPEI THIS AFTERNOON AND SIMILAR CONDITIONS ARE
EXPECTED IN THE COMING DAYS AS THE ITCZ IS EXPECTED TO SHIFT NORTH
AND BECOME MORE FRAGMENTED. DUE TO THIS, ALL FORECAST LOCATIONS MAY
EXPECT A LULL IN THE OVERALL WEATHER PATTERN AFTER MONDAY, THEN ITCZ
SHOWERS MAY START TO REBUILD STARTING NEAR MAJURO LATE WEEK.
MARINE CONDITIONS LOOK TO REMAIN BENIGN THROUGH THE WEEKEND.
COMBINED SEAS OF 3 TO 5 FEET NEAR POHNPEI AND KOSRAE AND UP TO 6 FEET
NEAR MAJURO ARE EXPECTED OVER THE NEXT SEVERAL DAYS. CHOPPY SEAS AND
OCCASIONAL GUSTS TO 20 KT ARE POSSIBLE ACROSS KOSRAE AND MAJURO
WATERS THROUGH TONIGHT.
WESTERN MICRONESIA
SATELLITE OBSERVATIONS SHOW SCATTERED SHOWERS ACROSS PALAU AND CHUUK
AND ISOLATED SHOWERS ACROSS YAP. ALTIMETRY AND BUOY DATA SHOW
COMBINED SEAS BETWEEN 2 TO 4 FEET.
OVERALL, LITTLE CHANGE IN THOUGHT FROM THE LAST COUPLE OF FORECASTS.
GUIDANCE HAS BACKED OFF SLIGHTLY FROM HIGHER POPS THIS WEEK, BUT
SCATTERED SHOWERS ARE STILL EXPECTED THROUGH MUCH OF THE PERIOD FOR
PALAU AND YAP AND LESS SO AFTER MONDAY FOR CHUUK. BOTH THE GFS AND
ECMWF SHOW THE GREATEST SURFACE CONVERGENCE OVER PALAU AND YAP DURING
THE MONDAY NIGHT AND TUESDAY PERIODS. THIS IS WHEN A POTENTIAL
INCREASE IN POPS TO HIGH-END SCATTERED (50%) TO NUMEROUS (60-70%) MAY
BEEN NEEDED WITH UPCOMING FORECAST CYCLES. FOR CHUUK, A LULL LOOKS TO
DEVELOP LATER THIS WEEK WITH ISOLATED SHOWERS OUTSIDE OF A TRADE-WIND
TROUGH THAT LOOKS TO MOVE IN WEDNESDAY OR WEDNESDAY NIGHT. AS WE HEAD
INTO NEXT WEEKEND, THE PATTERN ACROSS WESTERN MICRONESIA LOOKS TO
SHAKE UP AS A STRENGTHENING ITCZ MOVES INTO THE REGION.
LITTLE TO NO CHANGE WAS MADE WITH THE MARINE FORECAST. BENIGN
COMBINED SEAS OF 2 TO 4 FEET LOOK TO PREVAIL THROUGH THE FORECAST
PERIOD. WINDS ARE EXPECTED TO REMAIN LIGHT TO GENTLE WHILE VARIABLE
AT TIMES.
GUM WATCHES/WARNINGS/ADVISORIES
GU...NONE.
MP...NONE.
MARIANAS WATERS...NONE.
MARIANAS: KLEESCHULTE
EAST MICRONESIA: CRUZ
WEST MICRONESIA: WILLIAMS
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