794  
FXPQ60 PGUM 290728  
AFDPQ  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE TIYAN GU  
523 PM CHST WED MAR 29 2017  
   
MARIANAS SYNOPSIS
 
EAST WINDS, PARTLY CLOUDY SKIES AND  
ISOLATED SHOWERS PREVAIL ACROSS THE LOCAL AREA THIS AFTERNOON.  
 

 
   
DISCUSSION
 
 
LITTLE CHANGE MADE TO THE FORECAST. UPDATED WINDS WITH NEW GFS MODEL  
DATA. EAST WINDS OF 10 TO 20 MPH WILL PREVAIL ACROSS THE MARIANAS  
THROUGH FRIDAY NIGHT AS HIGH PRESSURE CENTERED TO THE NORTH  
INCREASES THE PRESSURE GRADIENT.  
 
A WEAK SHEAR LINE WILL PRODUCE MOSTLY CLOUDY SKIES AND PATCHY  
SHOWERS OVER THE LOCAL AREA THROUGH FRIDAY NIGHT. DEEP-LAYER  
MOISTURE WILL BE SHALLOW THROUGH THE WEEKEND SO ONLY EXPECT PARTLY  
CLOUDY SKIES AND ISOLATED SHOWERS AT THAT TIME. TRADE-WIND  
CONVERGENCE WILL INCREASE CLOUDS TUESDAY NIGHT AND WEDNESDAY.  
 

 
   
MARINE
 
 
OBSERVATIONS THIS MORNING FROM IPAN, RITIDIAN AND TANAPAG BUOYS  
INDICATE COMBINED SEA HEIGHTS OF 7 TO 8 FEET. THERE IS A NORTH SWELL  
OF OF AROUND 2 TO 3 FEET ENTERING THE AREA. THE NORTH SWELL HAS A  
PERIOD OF 11 SECONDS. CALCULATIONS PREDICT SURF ON NORTH FACING  
REEFS OF AROUND 5 FEET. EXPECT THE NORTH SWELL TO INCREASE TO 4 FEET  
ON FRIDAY AND REMAIN THAT HIGH THROUGH FRIDAY NIGHT. THIS WOULD  
PRODUCE A SURF OF 5 TO 7 FEET ON NORTH FACING REEFS. THERE IS ALSO A  
EAST TRADE-WIND SWELL WHICH WILL PERSIST THROUGH THE FORECAST. SURF  
ON EAST FACING REEFS IS EXPECTED TO BE 6 TO 8 FEET THROUGH AT LEAST  
SATURDAY.  
 
WINDS OVER THE MARINE AREA WILL BE IN THE 20 TO 25 KNOT RANGE WITH  
OCCASIONAL GUST TO 30 KNOTS ON TONIGHT. WINDS WILL DECREASE SLIGHTLY  
THURSDAY BUT STILL EXPECT FREQUENT GUST IN THE MID 20 KNOT RANGE  
THROUGH MUCH OF THURSDAY NIGHT. THESE WINDS ARE JUST HIGH ENOUGH FOR  
A SMALL CRAFT ADVISORY. OBSERVED COMBINED SEAS, AS MENTIONED EARLIER  
ARE 7 TO 8 FEET. MODEL DATA SHOW 7 TO 9 FEET THROUGH FRIDAY MORNING.  
THERE IS A POSSIBILITY THAT SEAS MAY BRIEFLY REACH 10 FEET...WHICH  
IS SMALL CRAFT ADVISORY CRITERIA...THROUGH THURSDAY NIGHT.  
 

 
 
   
EASTERN MICRONESIA
 
 
SCATTERED TO NUMEROUS SHOWERS AND A FEW THUNDERSTORMS ARE SEEN  
NEAR POHNPEI AND KOSRAE AHEAD OF A TRADE-WIND SURGE. NORTHEAST  
TRADES WILL EVENTUALLY PUSH SHOWERS TO THE SOUTH OF POHNPEI EARLY  
THURSDAY MORNING BUT SHOWERS WILL PERSIST ANOTHER COUPLE OF DAYS  
AT KOSRAE. FARTHER EAST, MORE CLOUDS AND A FEW SHOWERS ARE SEEN  
SOUTH AND EAST OF MAJURO. THIS AREA WILL EXPAND AND MOVE WESTWARD  
LATE IN THE WEEK AND INTO THE WEEKEND, KEEPING KOSRAE MOSTLY  
CLOUDY WITH ISOLATED THUNDERSTORMS. MOST SHOWERS ARE EXPECTED TO  
STAY SOUTH OF MAJURO, ALTHOUGH THE ATOLL COULD SEE AN INCREASE IN  
SHOWERS AROUND FRIDAY.  
 
HIGH SURF ADVISORY CONTINUES AT KOSRAE UNTIL THURSDAY EVENING AS  
TRADE-WIND SWELL EVENTUALLY SUBSIDE. ALSO, BOTH MAJURO AND KOSRAE  
MAY STILL SEE SOME INUNDATION AROUND TIMES OF HIGH TIDES THROUGH  
THURSDAY AFTERNOON.  
 

 
   
WESTERN MICRONESIA
 
 
A DISTURBANCE SOUTHEAST OF KOROR AND YAP IS GENERATING WIDESPREAD  
CLOUDINESS AND SHOWERS IN THE AREA. SHOWERS WILL INCREASE AT  
KOROR TONIGHT AND CONTINUE THROUGH FRIDAY AS THE DISTURBANCE  
DRIFTS WESTWARD. YAP WILL SEE ISOLATED SHOWERS AND A SMALL CHANCE  
OF THUNDERSTORMS THE NEXT COUPLE OF DAYS.  
 
SHOWERS AT CHUUK WILL CONTINUE ON THROUGH TONIGHT BUT GRADUALLY MOVE  
OFF TO THE SOUTHWEST BY THURSDAY MORNING AS STRONGER NORTHEAST  
TRADES PUSH THE CONVERGENCE BOUNDARY FARTHER SOUTHWEST AND DRIER AIR  
MOVES INTO THE AREA.  
 

 
 
   
GUM WATCHES/WARNINGS/ADVISORIES
 
 
GU...NONE.  
MARIANAS WATERS...SMALL CRAFT ADVISORY UNTIL 10 PM CHST THURSDAY FOR PMZ151>154.  
 

 
 

 
 
ZIOBRO/W. AYDLETT  
 
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