254
FXPQ50 PGUM 210718
AFDGUM
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TIYAN GU
518 PM CHST TUE OCT 21 2025
MARIANAS SYNOPSIS
GENTLE TO MODERATE SOUTHEASTERLIES PREVAIL ACROSS THE REGION.
SATELLITE IMAGERY AND DOPPLER RADAR INDICATE A LINE OF SHOWERS
APPROACHING GUAM'S SOUTHEASTERN SHORES. BUOYS AND ALTIMETRY SHOW SEAS
ARE BETWEEN 5 AND 6 FEET.
DISCUSSION
AS THE AFOREMENTIONED LINE OF SHOWERS MAKES ITS WAY ACROSS GUAM AND
ROTA, A THUNDERSTORM OR TWO IS LIKELY TO DEVELOP DURING PASSAGE.
SHOWERS ARE EXPECTED TO REMAIN SCATTERED, BUT WILL BE HEAVY AT
TIMES, BRINGING OCCASIONALLY STRONG GUSTS IN THE NEXT FEW HOURS.
PATCHY SHOWERS AND SOME THUNDERSTORMS ARE EXPECTED THROUGH WEDNESDAY,
BEFORE TAPERING DOWN SLOWLY THEREAFTER AS THIS SURFACE TROUGH EXITS
TO THE WEST AND ALLOWS A DRIER TRADE-WIND REGIME TO ENSUE FOR THE
REST OF THE WEEK.
MARINE
A LINE OF SHOWERS COMING IN FROM THE SOUTHEAST MAY BRING
OCCASIONALLY STRONG WINDS DURING PASSAGE IN THE EARLY EVENING HOURS.
COMBINED SEAS OF 4 TO 6 FEET, COMPRISED OF A DOMINANT TRADE SWELL
AND DIMINISHING NORTHERLY SWELL, MAY DROP A FOOT OR TWO IN THE SECOND
HALF OF THE WEEK WHEN ALL INCOMING SWELLS WEAKEN. A MODERATE RISK OF
RIP CURRENTS IS EXPECTED ALONG NORTH AND EAST FACING REEFS OF THE
MARIANAS FOR AT LEAST THE NEXT FEW DAYS, BEFORE POTENTIALLY BECOMING
LOW ALONG NORTH FACING REEFS LATER ONCE THE AFOREMENTIONED NORTHERLY
SWELL DIMINISHES.
EASTERN MICRONESIA
EASTERN MICRONESIA WILL BE DOMINATED BY AN INTER TROPICAL CONVERGENCE
ZONE FOR THE NEXT SEVERAL DAYS. POHNPEI AND MAJURO WILL BE CLOSE TO
THE CENTER, AND WILL THEREFORE SEE SCATTERED SHOWERS OR MORE FOR THE
ENTIRE PERIOD. KOSRAE WILL BE AT THE SOUTHERN EDGE, AND AS THE ITCZ
UNDULATES, WILL MOVE INTO AND OUT OF THE CORE, AND PERHAPS EVEN LEAVE
THE ITCZ AT TIMES. THE MOST LIKELY TIMES FOR KOSRAE TO EMERGE FROM
UNDER THE ITCZ ARE TONIGHT, WEDNESDAY, AND THURSDAY. AS IT
STRENGTHENS, FRIDAY THROUGH SUNDAY IT LOOKS LIKE KOSRAE WILL BE IN
THE THICK OF IT AS WELL.
COMBINED SEAS ARE 4 TO 6 FEET WITH A FEW 7 FOOTERS EARLY. THIS RAISED
THE POSSIBILITY OF A HIGH SURF ADVISORY AT KOSRAE. WHEN WE CHECKED
THE BUOY THOUGH, THE PEAK PERIOD THERE IS 6 SECONDS, WHICH MEANS IT
IS MOSTLY WIND WAVE AND HAS VERY LITTLE POTENTIAL FOR SHOALING, WHICH
IS WHAT INCREASES SURF HEIGHT ABOVE THE SEA HEIGHT. THE SMALL CRAFT
ADVISORY AT MAJURO IS OUT MAINLY FOR THE POTENTIAL FOR GUSTS UP TO 30
KNOTS IN HEAVIER SHOWERS. WINDS DIMINISH SLIGHTLY AFTER TONIGHT,
WHICH WILL REDUCE THAT POTENTIAL ENOUGH TO DROP THE ADVISORY. FOR
NOW, ASCAT SHOWS WINDS OF 20 KNOTS JUST EAST OF THEM, WITH WINDS OF
25 KNOTS A BIT FURTHER EAST, WHICH COULD ADVECT INTO THEIR WATERS.
WESTERN MICRONESIA
--THIS SECTION WILL BE UPDATED ONCE READY--
GUM WATCHES/WARNINGS/ADVISORIES
GU...NONE.
MP...NONE.
MARIANAS WATERS...NONE.
MARIANAS: MONTVILA
EAST MICRONESIA: STANKO
WEST MICRONESIA: SCHANK
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