969
FXPQ50 PGUM 160800
AFDGUM
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TIYAN GU
600 PM CHST SUN FEB 16 2025
MARIANAS SYNOPSIS
SKIES ARE PARTLY CLOUDY ACROSS THE MARIANAS WITH A FEW SHOWERS SEEN
OVER SAIPAN AND TINIAN COASTAL WATERS, ASSOCIATED WITH A SHEAR LINE
FRAGMENT DRAPED OVER THE NORTHERN CNMI. SURFACE OBSERVATIONS AND
ALTIMETRY DATA SHOW MOSTLY MODERATE TRADE WINDS WITH FREQUENT GUSTS
TO AROUND 25 MPH.
DISCUSSION
A DRY TRADE WIND REGIME CONTINUES. MODERATE TO FRESH TRADES WILL
DIMINISH OVER THE NEXT FEW DAYS BEFORE A TRADE-WIND SURGE SETS UP
FOR THE LATTER HALF OF THE WEEK. THIS WILL MAINLY IMPACT THE MARINE
AND SURF FORECASTS LATER IN THE WEEK, AS SEA CONDITIONS MAY BECOME
HAZARDOUS TO SMALL CRAFT AROUND THURSDAY ONWARD. IN THE MEANTIME,
MUCH OF THE WEATHER FOR THE MARIANAS WILL BE INFLUENCED BY NEARBY
PASSING SHEAR LINE FRAGMENTS, PROPAGATED BY LOW-PRESSURE SYSTEMS
FURTHER NORTH. THE DECAYING SHEAR LINE OVER THE NORTHERN CNMI WILL
GRADUALLY LIFT NORTHWEST AND AWAY FROM SAIPAN TONIGHT INTO TOMORROW,
BUT GUAM AND ROTA COULD SEE A SHOWER OR TWO ALONG THE OUTER PERIPHERY
OF ANOTHER SUCH FEATURE EAST OF THE ISLANDS. OVERALL, ONLY ISOLATED
SHOWERS ARE EXPECTED DURING THE FORECAST PERIOD, AND DRY CONDITIONS
LOOK TO CONTINUE.
MARINE
LATEST BUOY AND ALTIMETRY DATA SHOWS COMBINED SEAS OF 5 TO 7 FEET
ACROSS THE MARIANAS. GENTLE TO MODERATE WINDS ARE EXPECTED TO
CONTINUE THROUGH MONDAY, WANING MONDAY NIGHT INTO TUESDAY, BECOMING
LIGHT TO GENTLE AS THE SUBTROPICAL RIDGE WEAKENS NORTH OF THE
MARIANAS. WINDS AND SEAS WILL INCREASE IN THE LATTER HALF OF THE WEEK
AS A STRONG SUBTROPICAL RIDGE SETS UP NORTH OF THE REGION, PRODUCING
A WIDESPREAD TRADE-WIND SURGE. A MODERATE RISK OF RIP CURRENTS IS
EXPECTED TO CONTINUE FOR WEST, NORTH, AND EAST FACING REEFS FOR THE
NEXT FEW DAYS.
FIRE WEATHER
A TRACE OF RAIN FELL AT THE AIRPORT YESTERDAY AND THERE HAS NOT BEEN
A WETTING RAIN IN SEVERAL DAYS, WHICH ALLOWED FOR THE KBDI TO RISE TO
618. A WETTING RAIN OF 0.20 INCHES OR HIGHER IS NOT EXPECTED OVER THE
NEXT FEW DAYS. THE CURRENT FORECAST SHOWS RELATIVE HUMIDITY VALUES
INCREASING ABOVE 60% FOR TOMORROW AS WINDS LOOK TO DECREASE, WHICH
WILL BRING FIRE WEATHER CONDITIONS BELOW RED FLAG CRITERIA. AS SUCH,
THE RED FLAG WARNING IS NO LONGER IN EFFECT. HOWEVER, A FIRE WEATHER
WATCH IS NOW IN EFFECT, AS VERY DRY CONDITIONS AND OCCASIONALLY GUSTY
WINDS WILL MAINTAIN A HIGH FIRE THREAT. WINDS ARE EXPECTED TO DIMINISH
THROUGH TUESDAY BEFORE INCREASING FOR THE LATTER HALF OF THE WEEK.
EASTERN MICRONESIA
TWO AREAS OF TRADE CONVERGENCE ARE GENERATING MODERATE CONVECTION IN
THE REGION. ONE IS SOUTH TO SOUTHWEST OF KOSRAE, AND THE OTHER IS
NEAR AND EAST OF MAJURO THIS AFTERNOON. THESE FEATURES ARE EXPECTED
TO SLOWLY DRIFT NORTH-NORTHWEST AND WEAKEN, BRINGING SCATTERED
SHOWERS AND ISOLATED THUNDERSTORMS TO MAJURO THROUGH AT LEAST
TONIGHT AND TO KOSRAE AROUND MIDNIGHT THROUGH MONDAY. RELATIVELY DRY
WEATHER IS EXPECTED AT POHNPEI THIS WEEK. MODELS SHOW A SERIES OF
WEAK TROUGHS PASSING THROUGH, BUT OVERALL, SHOWERS LOOK TO STAY
ISOLATED THIS WEEK. THIS DRIER TRADE PATTERN IS EXPECTED TO EXTEND TO
KOSRAE AND MAJURO BY TUESDAY. ADDITIONALLY, MODERATE EAST TO
NORTHEAST TRADES BECOME MODERATE TO FRESH AROUND MIDWEEK AS HIGH
PRESSURE BUILDS TO THE DISTANT NORTH, INCREASING THE PRESSURE
GRADIENT ACROSS THE REGION.
THE HIGH SURF ADVISORY FOR POHNPEI AND KOSRAE WAS ALLOWED TO EXPIRE
THIS AFTERNOON. LONG-PERIOD NORTH SWELL CONTINUES TO MOVE ACROSS THE
REGION, HOWEVER, SURF HEIGHTS HAVE FALLEN BELOW HAZARDOUS CRITERIA.
ANOTHER PULSE OF NORTH SWELL ARRIVES TUESDAY AND WEDNESDAY, LIKELY
PRODUCING HAZARDOUS SURF ONCE AGAIN. ALTIMETRY AND BUOY DATA SHOW
COMBINED SEAS OF 6 TO 8 FEET, EXPECTED TO DECREASE TO 5 TO 7 FEET
TONIGHT, THEN INCREASE BACK UP TO 7 TO 9 FEET WITH THE ARRIVAL OF
NORTH SWELL.
WESTERN MICRONESIA
A SEASONAL TRADE-WIND REGIME IS EXPECTED TO PERSIST ACROSS THE REGION
FOR MUCH OF THE FORECAST PERIOD. ISOLATED SHOWERS TONIGHT WILL BE
FOLLOWED BY INCREASING SHOWERS AT PALAU MONDAY, AND MONDAY NIGHT AT
YAP, AS A BROAD SURFACE TROUGH MOVES ACROSS THE WESTERN PORTIONS OF
MICRONESIA. AS ANOTHER HIGH PRESSURE CELL MOVES OFF THE COAST OF
CHINA AND THEN ACROSS JAPAN, A DRIER REGIME WILL RETURN ONCE AGAIN IN
THE SECOND HALF OF THE WEEK. CHUUK WILL NOT SEE A SIGNIFICANT CHANGE
IN WEATHER, WITH ONLY ISOLATED SHOWERS AND OCCASIONALLY BREEZY
CONDITIONS EXPECTED FOR MUCH OF THE WEEK.
COMBINED SEAS OF 5 TO 7 FEET ARE EXPECTED AT PALAU, YAP AND CHUUK FOR
AT LEAST THE NEXT SEVERAL DAYS, FOLLOWED BY ANOTHER ROUND OF A NORTH
SWELL PULSE MAKING ITS WAY ACROSS THE REGION, POSSIBLY INCREASING
SEAS BY ANOTHER 2 TO 4 FEET BEFORE THE NEXT WEEKEND.
GUM WATCHES/WARNINGS/ADVISORIES
GU...RED FLAG WARNING UNTIL 5 PM CHST THIS AFTERNOON FOR GUZ001.
FIRE WEATHER WATCH THROUGH THURSDAY AFTERNOON FOR GUZ001.
MP...NONE.
MARIANAS WATERS...NONE.
MARIANAS: DECOU
EAST MICRONESIA: CRUZ
WEST MICRONESIA: MONTVILA
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