519
FXPQ50 PGUM 271913
AFDGUM
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TIYAN GU
513 AM CHST TUE APR 28 2026
MARIANAS UPDATE
SATELLITE AND RADAR OBSERVATIONS SHOW A FEW SHOWERS PUSHING WEST OF
THE MARIANAS ISLAND ACROSS THE WESTERN COASTAL WATERS. ALTIMETRY AND
BUOY DATA SHOW COMBINED SEAS BETWEEN 5 AND 8 FEET.
NO CHANGES WERE MADE WITH THIS FORECAST PACKAGE. DRY CONDITIONS WILL
CONTINUE FOR THE NEXT SEVERAL DAYS AS A DRY TRADE-WIND PATTERN
TAKES SHAPE ACROSS THE MARIANAS. COMBINED SEAS OF 5 TO 8 FEET ARE IN
PLACE ACROSS THE MARIANAS. SEAS ARE EXPECTED TO REMAIN BELOW SMALL
CRAFT ADVISORY CRITERIA, BUT A HIGH RISK FOR RIP CURRENTS ALONG EAST
FACING REEFS AND HAZARDOUS SURF ALONG NORTH FACING REEFS WILL BE
POSSIBLE TOMORROW.
TROPICAL UPDATE
THE JOINT TYPHOON WARNING CENTER'S (JTWC) INVEST 91W IS CENTER NEAR
4N160E AND REMAINS VERY WEAK AND DISORGANIZED. GUIDANCE CONTINUES TO
SHOW A WIDE ARRAY OF SOLUTIONS WITH THIS STORM SYSTEM.
CONFIDENCE ON ANY SCENARIO REMAINS EXTREMELY LOW AT THIS TIME.
WHAT'S IMPORTANT IS TO FOCUS ON MONITORING FORECASTS AND BULLETINS
OVER THE NEXT FEW DAYS. AS CONFIDENCE IMPROVES OVER THE COMING DAYS,
THIS INFORMATION WILL BE CONVEYED THROUGH OUR FORECASTS AND
BULLETINS. BE PREPARED, BUT NO NEED TO WORRY YET.
EASTERN MICRONESIA UPDATE
AN ACTIVE WEATHER PATTERN CONTINUES ACROSS EASTERN MICRONESIA. INVEST
91W REMAINS WEAK, BUT IT IS INTERACTING WITH SEVERAL SMALLER
DISTURBANCES TO PRODUCE LOCALLY HEAVY RAINFALL. INVEST 91W IS
EXPECTED TO REMAIN WEAK OVER THE NEXT SEVERAL DAYS BEFORE IT BEGINS
TO CONSOLIDATE SOME THIS WEEKEND. THOSE ACROSS EASTERN MICRONESIA
SHOULD CONTINUE TO MONITOR FORECASTS FOR ANY CHANGES.
MARINE CONDITIONS WILL GENERALLY BE BENIGN BETWEEN 5 AND 7 FEET,
EXCEPT FOR AREAS OF HEAVY SHOWERS AND THUNDERSTORMS WHERE CHOPPY
CONDITIONS WOULD BE EXPECTED.
WESTERN MICRONESIA UPDATE
SCATTERED SHOWERS ARE EXPECTED ACROSS YAP TODAY WITH ISOLATED SHOWERS
SEEN ELSEWHERE. NO CHANGES WERE WITH THIS FORECAST PACKAGE. INCREASED
SHOWER ACTIVITY IS EXPECTED FOR YAP AND PALAU OVER THE NEXT COUPLE OF
DAYS AS A VERY WEAK DISTURBANCE MOVES ACROSS THE REGION.
COMBINED SEAS ARE BETWEEN 5 AND 7 FEET AND LOOK TO REMAIN BENIGN
ACROSS THE REGION. SOME CHOPPY SEAS WILL BE POSSIBLE NEAR HEAVIER
SHOWERS OR THUNDERSTORMS.
PREV DISCUSSION
/ISSUED 514 PM CHST MON APR 27 2026/
MARIANAS SYNOPSIS...
SATELLITE SHOWS MOSTLY CLEAR SKIES WITH ONLY A FEW LIGHT SHOWERS
OVER THE MARIANAS. BUOYS SHOW SEAS BETWEEN 5 AND 6 FEET WHILE
ALTIMETRY SHOWS SEAS BETWEEN 6 AND 8 FEET EAST OF THE WATERS AND 4
TO 5 FEET WEST.
DISCUSSION...
AN OVERALL VERY DRY PATTERN IS CURRENTLY IN PLACE ACROSS THE
MARIANAS, WITH MOSTLY CLEAR SKIES AND ONLY SPOTTY SHOWERS SEEN
ACROSS THE REGION. NOT MUCH OF A CHANGE IS EXPECTED FOR THE NEXT
SEVERAL DAYS. EXPECT POPS (PROBABILITY OF PRECIPITATION) TO REMAIN
AROUND 10 TO 20 PERCENT THROUGH THE WEEK AND INTO THE WEEKEND. NO
MAJOR CHANGES ARE EXPECTED UNTIL LATER NEXT WEEK.
MARINE...
BENIGN MARINE CONDITIONS ARE EXPECTED TO CONTINUE FOR THE NEXT FEW
DAYS. SEAS LOOK TO REMAIN BETWEEN 5 AND 7 FEET. WINDS WILL BE
MODERATE TO FRESH THROUGH THE END OF THE WEEK, BECOMING GENTLE TO
MODERATE FOR THE WEEKEND. TRADE-WIND SWELL LOOKS TO BUILD SLIGHTLY
AROUND WEDNESDAY NIGHT AND COULD RESULT IN A HIGH RISK OF RIP
CURRENTS ALONG EAST FACING REEFS.
TROPICAL SYSTEMS...
A VERY WEAK TROPICAL DISTURBANCE, JOINT TYPHOON WARNING CENTER'S
(JTWC) INVEST 91W IS CENTERED NEAR 4N131E. THE INVEST IS RATED SUB-
LOW, MEANING LITTLE DEVELOPMENT IS EXPECTED OVER THE NEXT FEW DAYS.
LATEST MODEL GUIDANCE FOR 91W SHOWS AN ARRAY OF DIFFERENT SOLUTIONS
OVER THE NEXT WEEK OR SO. THE EVOLUTION OF 91W IS STILL VERY MUCH
UNCERTAIN AND THE POSSIBILITIES ARE EXTENSIVE FOR NOW. WE COULD SEE
ANYTHING FROM A WEAK CIRCULATION MOVING THROUGH THE MARIANAS, EASTERN
OR WESTERN MICRONESIA OR ANYTHING STRONGER. CONFIDENCE ON ANY
SCENARIO REMAINS EXTREMELY LOW AT THIS TIME. WHAT'S IMPORTANT IS TO
FOCUS ON MONITORING FORECASTS AND BULLETINS OVER THE NEXT FEW DAYS.
AS CONFIDENCE IMPROVES OVER THE COMING DAYS, THIS INFORMATION WILL BE
CONVEYED THROUGH OUR FORECASTS AND BULLETINS. BE PREPARED, BUT NO
NEED TO WORRY YET.
EASTERN MICRONESIA...
A WET PATTERN IS IN STORE FOR THE AREA, AS ONE WEAK AND SLIGHTLY
ELEVATED CIRCULATION IS LOCATED SOUTH OF KOSRAE, WITH ANOTHER WEAK
AND SLIGHTLY ELEVATED CIRCULATION NEAR EQ174E. A TROUGH EXTENDS
NORTHEAST FROM THE SECOND CIRCULATION TO EAST OF MAJURO, WITH FAIRLY
ROBUST CONVECTIVE COVERAGE AND INTENSITY LOCATED ALONG AND EAST OF
THE TROUGH. OVER THE NEXT FEW DAYS, THE KOSRAE CIRCULATION IS
EXPECTED TO BECOME ROOTED AT THE SURFACE AND SLOWLY ORGANIZE. CURRENT
MODEL LOCATIONS VARY FROM SOUTH OF POHNPEI/WEST OF KOSRAE TO JUST
NORTH OF POHNPEI. INCREASING SURFACE CONVERGENCE, AIDED BY THE MAJURO
TROUGH PROGRESSING WESTWARD, WILL KEEP AT LEAST SCATTERED SHOWERS
AND ISOLATED THUNDERSTORMS IN THE FORECAST THROUGH THE WEEKEND,
POSSIBLY LONGER FOR SOME LOCATIONS. WITH THAT SAID, IT'S STILL WAY
TOO EARLY TO PIN DOWN TIMING, RAINFALL AMOUNTS, AND TEMPERATURES
POSSIBLY BEING COOLER (DUE TO RAIN RATE AND INTENSITY). INVEST 91W
ISN'T FORECAST TO BECOME BETTER ORGANIZED FOR A FEW DAYS, AND UNTIL
THIS OCCURS, WE OPTED TO GO WITH MORE OF A "BROAD BRUSH" FORECAST
WITH JUST A BRIEF PERIOD OF HEAVY RAINFALL MENTIONED IN PORTIONS OF
THE FORECAST FOR NOW. WITH THAT SAID, A LONGER DURATION/MORE
WIDESPREAD MENTION OF LOCALLY HEAVY RAIN POSSIBLE IN LATER FORECASTS.
AS FOR WINDS AND SEAS, GENTLE TO MODERATE WINDS WILL CONTINUE AT
POHNPEI AND MAJURO THROUGH MID WEEK, BEFORE DECREASING, WITH LIGHT TO
GENTLE WINDS EXPECTED AT KOSRAE. SEAS OF 5 TO 7 FEET WILL PERSIST THE
NEXT SEVERAL DAYS.
WESTERN MICRONESIA...
AN UNSETTLED WEATHER PATTERN CONTINUES OVER WESTERN MICRONESIA, AS
AN EMBEDDED CIRCULATION WITHIN THE NEAR-EQUATORIAL TROUGH (NET)
PROPAGATES SLOWLY WESTWARD ACROSS SOUTHERN YAP STATE. HIMAWARI
VISIBLE SATELLITE THIS AFTERNOON DEPICTS A WEAK LOW-LEVEL
CIRCULATION CENTER ROUGHLY AT 3N142E, WITH THE NET EXTENDING WESTWARD
TO 2N130E AND BEYOND, AND EAST-SOUTHEASTWARD TO EQ148. TO THE NORTH,
A VERY BROAD TROUGH EXTENDS SOUTH-SOUTHWEST, PASSING WEST OF THE
MARIANAS AND EAST OF YAP PROPER BEFORE MAKING A SLIGHT CURVE SOUTH-
SOUTHEASTWARD, WHERE IT INTERACTS WITH THE WEAK CIRCULATION. PATCHES
OF SCATTERED TO NUMEROUS SHOWERS ARE SPREAD ACROSS MUCH OF YAP STATE
THIS AFTERNOON, TO THE EAST OF PALAU AND YAP PROPER, AND WEST OF
WENO, CHUUK, MAINLY ALONG THE CIRCULATION'S NORTHERN PERIPHERY. AN
EXTENSIVE LINE OF SHOWERS IS SEEN ALONG THE NORTH-SOUTH ORIENTED
TROUGH TO THE EAST OF YAP PROPER, MOVING SLOWLY WESTWARD, AND A FEW
ISOLATED THUNDERSTORMS ARE SEEN BEHIND THIS LINE TO THE EAST.
CONDITIONS REMAIN QUIET AND DRY OVER PALAU, YAP PROPER, AND WENO,
CHUUK THIS AFTERNOON. LATEST MODEL GUIDANCE MAINTAINS A SLOW
WESTWARD PROPAGATION OF THE AFOREMENTIONED FEATURES TONIGHT, WITH
SHOWERS INCREASING TO SCATTERED FOR YAP PROPER ON TUESDAY MORNING AS
THE CIRCULATION SHIFTS TO ITS SOUTH AND THE CONNECTED TROUGH MOVES
OVERHEAD. SHOWERS BEGIN TO BUILD OVER PALAU LATE TUESDAY NIGHT AS
THE OVERALL DISTURBANCE MAKES A SLIGHT TURN TOWARD THE NORTHWEST,
AND TRADE-WIND CONVERGENCE ALONG ITS NORTHEAST FLANK INCREASES,
FOCUSING SHOWERS ALONG A BROAD LINE THAT EXTENDS OVER KOROR.
NUMEROUS SHOWERS, LOCALLY HEAVY AT TIMES, ARE EXPECTED THERE AROUND
MIDWEEK, BEFORE THE DISTURBANCE SHIFTS SLIGHTLY NORTHWARD THROUGH THE
REMAINDER OF THE WEEK, INCREASING SHOWERS FOR YAP AS WELL.
MEANWHILE, A TRADE-WIND TROUGH AND ITCZ FRAGMENT WILL BUILD SHOWERS
ACROSS CHUUK ON WEDNESDAY, WHICH LOOK TO REINVIGORATE AS A
TROPICAL DISTURBANCE DEVELOPS TO THE EAST OF WENO THROUGH THE
WEEKEND.
RECENT ALTIMETRY DATA INDICATES COMBINED SEAS AROUND 4 TO 6 FEET
ACROSS THE REGION. THE NORTHEAST TRADE SWELL LOOKS TO BUILD ACROSS
CHUUK OVER THE NEXT DAY OR SO AND ACROSS YAP AROUND MIDWEEK, WHICH
WILL INCREASE SEAS BY AROUND A FOOT OR TWO, THEN RELAX SLIGHTLY IN
THE LATTER HALF OF THE WEEK.
GUM WATCHES/WARNINGS/ADVISORIES
GU...NONE.
MP...NONE.
MARIANAS WATERS...NONE.
MARIANAS/EAST AND WEST MICRONESIA/TROPICAL UPDATE: MESA
MARIANAS/EAST AND WEST MICRONESIA/TROPICAL UPDATE: WILLIAMS
MARIANAS: KLEESCHULTE
EAST MICRONESIA: DOLL
WEST MICRONESIA: DECOU
TROPICAL: KLEESCHULTE
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