Area Forecast Discussion
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000
FXPQ60 PGUM 292113
AFDPQ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TIYAN GU
713 AM CHST SUN AUG 30 2015

.SYNOPSIS...LIGHT SOUTHWEST WINDS AND A FEW SMALL SHOWERS
PREVAIL ACROSS THE MARIANAS THIS MORNING. LIGHT WINDS AND
ISOLATED SHOWERS ARE ALL THAT IS EXPECTED THROUGH THE
WEEKEND AND INCLUDING MOST OF THE COMING WEEK.

&&

.DISCUSSION...
LITTLE CHANGE MADE TO THE FORECAST. SCATTEROMETER DATA FROM LAST
NIGHT DEPICTED A WEAK CIRCULATION WEST OF SAIPAN. A SURFACE TROUGH
WAS ALSO ASSOCIATED WITH THE TROUGH. LIGHT SOUTHWEST WINDS PREVAIL
ACROSS THE MARIANAS THIS MORNING SOUTH AND EAST OF THE
CIRCULATION.

HIGH PRESSURE BUILDING IN FROM THE NORTH WILL PUSH THE TROUGH
SOUTH OF GUAM. THIS WILL RESULT IN WINDS BECOMING MORE EASTERLY
TONIGHT AND REMAIN THAT WAY THROUGH AT LEAST MID-WEEK. DESPITE THE
CHANGE IN WIND DIRECTION WINDS ARE PREDICTED TO BE LIGHT THROUGH
THE FORECAST.

MODELS KEEP DEEP LAYER MOISTURE AT A MINIMUM TODAY WITH ONLY A
SLIGHT INCREASE BY THE FIRST HALF OF THE COMING WEEK. WITH THE
LOW MOISTURE EXPECT ONLY A FEW SHOWERS THROUGH THE NEXT FEW DAYS.

MODELS DO SHOW WEAK LOW-LEVEL CONVERGENCE OVER THE MARIANAS MONDAY
NIGHT THROUGH WEDNESDAY NIGHT. IT MAY BRING IN A FEW CLOUDS BUT
CONFIDENCE IN THIS IS NOT SO HIGH SO IT HAS NOT BEEN ADDED TO THE
FORECAST YET.

&&

.MARINE...
RITIDIAN AND SAIPAN BUOY DATA SHOWS SEAS ARE AROUND 5 TO 7 FEET.
THE NORTH SWELL STILL PERSIST BUT HAS DECREASED SINCE YESTERDAY.
THE BUOYS SHOW A NORTH SWELL OF 5 TO 7 FEET WITH A PERIOD OF
AROUND 13 TO 15 SECONDS.

THIS NORTH SWELL IS FROM THE REMAINS OF ATSANI WHICH HAS BECOME A
LOW PRESSURE SYSTEM EAST OF JAPAN. THIS LOW PRESSURE SYSTEM IS
INCREASING ITS DISTANCE WHILE WEAKENING SO THE SWELL SHOULD BE
DECREASING. EXPECT HAZARDOUS SURF HEIGHT FROM THIS SWELL OF 7 TO 9
FEET ON NORTH FACING REEFS TODAY. SURF IS PREDICTED TO FALL BELOW
HAZARDOUS LEVELS BY THIS EVENING.

&&

.EASTERN MICRONESIA...
MODERATE MONSOONAL WINDS ACROSS CHUUK AND POHNPEI WILL DECREASE
TO GENTLE LATER TODAY. THIS WILL ALLOW FAIR WEATHER ALREADY OVER
MAJURO AND KOSRAE TO SPREAD WESTWARD OVER BOTH LOCALES. AT THE
UPPER- LEVELS...A TROUGH CAN BE SEEN ON THE WV SATELLITE LOOPS
PROGRESSING WESTWARD FROM THE MARSHALL ISLANDS. SOUTHEASTERLY FLOW
IN THE WAKE OF THIS TROUGH IS ADVECTING MID TO UPPER-LEVEL
MOISTURE NORTHWARD FROM THE SOUTHERN HEMISPHERE. THIS PROCESS
SHOULD COMBINE WITH THE EXISTING MODEST MONSOON PATTERN TO
INCREASE THE CHANCE OF SHOWERS AND THUNDERSTORMS NEAR MAJURO AND
KOSRAE BY MONDAY MORNING. AS THE UPPER TROUGH MOVES FARTHER
WESTWARD PASSING POHNPEI AND CHUUK ON MONDAY EVENING...A GRADUALLY
WETTING TREND WILL RETURN THERE. THIS RELATIVELY WET REGIME MIGHT
CONTINUE ACROSS THE ENTIRE REGION THRU MIDWEEK.

THE WEST SWELL GENERATED BY MONSOONAL WINDS IS SUBSIDING FROM CHUUK
STATE EASTWARD TO THE MARSHALL ISLANDS. HOWEVER...PERSISTENT NORTH
AND SOUTHEAST SWELLS ARE GOING TO MAINTAIN SEAS OF 6 TO 8 FEET AND
HIGHER RISK OF RIP CURRENTS THRU MONDAY EVENING. STARTING TUESDAY...
BOTH SWELLS SHOULD GRADUALLY DECLINE AND ALLOW SEAS AND RIP CURRENT
RISK TO DECREASE.&&

.WESTERN MICRONESIA...
REASONING FOR THE CHUUK FORECAST IS INCLUDED IN THE EASTERN
MICRONESIA SECTION DUE TO A SIMILAR WEATHER PATTERN.

MONSOONAL WEST TO SOUTHWEST WINDS ARE STRENGTHENING ACROSS THE
REPUBLIC OF PALAU AND YAP STATE THIS MORNING. IN CONJUNCTION WITH AN
UPPER-LEVEL TROUGH APPROACHING FROM THE EAST...SPORADIC CONVECTION
HAS BEEN FLARING UP NEAR YAP. THIS WILL CONTINUE THERE THRU MIDWEEK
AND ALSO REACH KOROR LATER TONIGHT. FUTURE SHIFTS WILL PROBABLY NEED
TO INCREASE SHOWER COVERAGE FOR KOROR. TOWARD THE WEEKEND...
WEAKENING MONSOON WINDS MIGHT ALLOW SOME IMPROVEMENT TO BEGIN.

&&

.GUM WATCHES/WARNINGS/ADVISORIES...
GU...HIGH SURF ADVISORY UNTIL 6 PM CHST THIS EVENING FOR GUZ001>004.

MARIANAS WATERS...NONE.
&&

$$

ZIOBRO/CHAN



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