116
FXPQ50 PGUM 250758
AFDGUM
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TIYAN GU
558 PM CHST FRI APR 25 2025
MARIANAS SYNOPSIS
GENTLE TO MODERATE TRADES PREVAIL. SATELLITE IMAGERY AND DOPPLER
RADAR INDICATE RUN-OF-THE-MILL TRADES MAKING THEIR WAY ACROSS THE
REGION. BUOYS AND ALTIMETRY INDICATE SEAS ARE 4 TO 5 FEET.
DISCUSSION
MOSTLY DRY CONDITIONS WILL BE FOLLOWED BY A BRIEF PERIOD OF LOW-END
SCATTERED SHOWERS BROUGHT BY A PASSING MINOR TROUGH LATER IN THE
WEEKEND. AFTER, A DRIER REGIME WILL RETURN AS MOST OF THE CONVECTION
IN THE REGION REMAINS SOUTH OF THE MARIANAS.
MARINE
COMBINED SEAS OF 4 TO 6 FEET ARE EXPECTED TO REMAIN AS SUCH AT LEAST
INTO EARLY NEXT WEEK. A MODERATE RISK OF RIP CURRENTS IS EXPECTED
ALONG NORTH AND EAST FACING REEFS FOR AT LEAST THE NEXT SEVERAL DAYS.
AS SECONDARY NORTH SWELL BEGINS TO TAPER DOWN LATE SUNDAY, RIP
CURRENT RISK MAY FALL BACK TO LOW ALONG NORTH FACING REEFS AS EARLY
AS MONDAY.
FIRE WEATHER
SO FAR TODAY, 0.04 INCHES OF RAIN HAS FALLEN SINCE MIDNIGHT, WITH NO
SIGNIFICANT RAINFALL EXPECTED UNTIL MIDNIGHT. AS SUCH, THE KBDI IS
EXPECTED TO INCREASE FURTHER, WHICH IS AT 675 CURRENTLY (HIGH
CATEGORY). A MINOR TROUGH WILL BRINGER HIGHER RAINFALL AMOUNTS OVER
THE WEEKEND, BUT NOT LIKELY TO BE WETTING RAINS, SO THE KBDI MAY
CONTINUE TO CREEP UPWARDS. EVEN SO, WINDS ARE EXPECTED TO REMAIN
GENTLE TO MODERATE, SO CONDITIONS CRITICAL TO FIRE WEATHER ARE NOT
EXPECTED AT LEAST OVER THE NEXT FEW DAYS.
EASTERN MICRONESIA
A MUCH DRIER PATTERN IS IN PLACE ACROSS EASTERN MICRONESIA THAN WHAT
IS FAVORED BY THE MODELS. THERE IS A VERY WEAK BAND OF TRADE-WIND
CONVERGENCE EVIDENT ON THE LATEST ASCAT ANALYSIS AND SATELLITE DATA
STRETCHING EAST ACROSS POHNPEI TO JUST NORTH OF KOSRAE, ENDING WEST
OF MAJURO. CONVECTION LOOKS TO INCREASE THROUGH THE EVENING ALONG
THIS BAND FOR BOTH KOSRAE AND POHNPEI AS VERY WEAK TROUGHS MOVE
THROUGH THE REGION, INTERACTING WITH THE CONVERGENCE. MODEL GUIDANCE
IS FAVORING A LARGE INCREASE IN CONVECTION, WITH NUMEROUS SHOWERS
SHOWING UP ON THE GFS AND ECMWF ACROSS POHNPEI AND KOSRAE. HOWEVER,
THIS DOES NOT APPEAR LIKELY AS THE CONVERGENCE AND TROUGHS WILL
REMAIN POORLY ORGANIZED. BASED ON A LARGE DEGREE OF UNCERTAINTY WITH
THE CONVECTIVE DEVELOPMENT ACROSS THE AREA, MAINTAINED SCATTERED
SHOWERS THROUGH THE WEEKEND AND THROUGH THE END OF THE COMING WEEK.
SHOWERS LOOK TO REMAIN ISOLATED ACROSS MAJURO THROUGH SATURDAY NIGHT
BEFORE A MORE PRONOUNCED TROUGH MOVES IN FROM EAST OF THE DATE LINE,
HELPING TO INCREASE CONVERGENCE ACROSS THE MARSHALLS. IT DOES APPEAR
LIKELY THAT THE STRONGEST CONVECTION WILL BE EARLY NEXT WEEK FOR
MAJURO AND AROUND MIDWEEK FOR KOSRAE, WITH THE BULK OF THE CONVECTION
REMAINING JUST SOUTH OF POHNPEI. MAJURO DOES LOOK TO DRY OUT AGAIN
NEAR THE MIDDLE OF NEXT WEEK.
OTHER THAN SHOWERS AND THUNDERSTORMS, CONDITIONS LOOK TO STAY
RELATIVELY BENIGN ACROSS THE MARINE ENVIRONMENT THROUGH THE MIDDLE OF
NEXT WEEK. FOR POHNPEI AND KOSRAE, EXPECT GENTLE TO MODERATE TRADE
WINDS THROUGH THE PERIOD. FOR MAJURO, THE DIFFERENCE IS A BRIEF
PERIOD OF OCCASIONALLY FRESH WINDS EARLY NEXT WEEK. SEAS ARE
EXPECTED TO REMAIN AT OR BELOW 7 FEET ACROSS THE REGION THROUGH THE
PERIOD. THERE IS, HOWEVER, A POSSIBILITY THAT A NORTHEAST SWELL COULD
BUILD HIGH ENOUGH TO PRODUCE HAZARDOUS SURF CONDITIONS ALONG NORTH
FACING REEFS OF POHNPEI, AND NORTH AND EAST FACING REEFS OF KOSRAE
OVER THE WEEKEND. THE NIGHT SHIFT WILL NEED TO TAKE A CLOSER LOOK TO
SEE IF THE SWELL WILL BE ENOUGH OF A NORTHERLY COMPONENT TO PRODUCE 9
FOOT SURF ALONG NORTH FACING REEFS AT BOTH LOCATIONS. IF THE SWELL
REMAINS MORE OF AN EASTERLY COMPONENT, HAZARDOUS SURF CAN BE EXPECTED
FOR EAST FACING REEFS OF KOSRAE, DUE TO THE LOWER THRESHOLD FOR
HAZARDOUS SURF.
WESTERN MICRONESIA
THE CIRCULATION EMBEDDED IN THE NEAR-EQUATORIAL TROUGH (NET) IS NOW
DESIGNATED 99W BY JTWC, CURRENTLY RATED AS SUB-LOW FOR DEVELOPMENT.
AFTERNOON SCATTEROMETRY DATA SHOWS THE CIRCULATION NEAR 4N133E WITH
VISIBLE SATELLITE IMAGERY CONTINUING TO SHOW THE DEEPER CONVECTION
WITHIN THE MOIST WESTERLY FLOW, FOCUSED ALONG THE SOUTHERN PORTION
OF THE CIRCULATION AND NET. A NORTHWARD SHIFT OF THE NET IS EXPECTED
OVER THE WEEKEND AND EARLY NEXT WEEK, WHILE THE 99W MEANDERS
NORTHWESTWARD AS A BROAD CIRCULATION. THE POTENTIAL FOR SOME
DEVELOPMENT IS THERE, BUT NOT FOR ANOTHER FEW DAYS, SO WILL CONTINUE
TO MONITOR IN THE COMING DAYS. WITH ITS CURRENT TRACK, IT SHOULD
PASS WELL WEST OF THE MAIN ISLANDS OF PALAU, BUT WILL STILL BE IN A
GOOD SPOT TO STEER MOIST SOUTHWESTERLIES TOWARDS THE ISLANDS. WENT
AHEAD AND ADDED THE POTENTIAL FOR LOCALLY HEAVY SHOWERS AND GUSTS
WITH HEAVIER SHOWERS LATE WEEKEND AND EARLY NEXT WEEK, BUT CONTINUE
TO MONITOR FORECASTS AS TIMING AND INTENSITY OF CONVECTION MAY SHIFT
WITH SUBSEQUENT MODEL RUNS. YAP PROPER WILL ALSO SEE A TREND TOWARDS
MORE UNSETTLED WEATHER, BUT ENSEMBLE MODELS SHOW THE BULK OF ACTIVITY
NEAR, BUT MAINLY SOUTHWEST OF THE ISLAND AT THIS TIME. FOR CHUUK,
MODERATE CONVERGENCE BEHIND A BROAD TROUGH TO THE WEST IS EXPECTED TO
MAINTAIN SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS OVER THE NEXT
DAY OR SO, THEN A NORTHWARD SHIFT OF THE NET AND POSSIBLY THE
DEVELOPMENT OF ANOTHER EMBEDDED, WEAK DISTURBANCE WILL ALSO INCREASE
CONVERGENCE ACROSS CENTRAL MICRONESIA OVER THE WEEKEND AND THROUGH
THE MIDDLE OF NEXT WEEK, MAINTAINING SCATTERED SHOWERS ACROSS CHUUK.
BENIGN MARINE CONDITIONS CONTINUE OVER THE NEXT SEVERAL DAYS WITH
COMBINED SEAS OF 3 TO 5 FEET EXPECTED, COMPRISED OF MINOR TRADE SWELL
AND WIND WAVES. A LONGER-PERIOD NORTH SWELL REACHES THE REGION OVER
THE WEEKEND; THIS MAY SLIGHTLY ADD TO SEAS, BUT WOULD MAINLY BOOST
SURF ALONG NORTH-FACING REEFS. NEITHER SEAS NOR SURF ARE EXPECTED TO
REACH HAZARDOUS LEVELS AT THIS TIME. WINDS WILL BE GENTLE TO
MODERATE, BUT FRESH GUSTS ARE POSSIBLE WITH THE UNSETTLED WEATHER
PATTERN DEVELOPING IN FAR WESTERN MICRONESIA LATE WEEKEND AND EARLY
NEXT WEEK.
GUM WATCHES/WARNINGS/ADVISORIES
GU...NONE.
MP...NONE.
MARIANAS WATERS...NONE.
MARIANAS: MONTVILA
EAST MICRONESIA: KLEESCHULTE
WEST MICRONESIA: CRUZ
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