Area Forecast Discussion
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000
FXPQ60 PGUM 180533
AFDPQ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TIYAN GU
333 PM CHST THU DEC 18 2014

.MARIANAS SYNOPSIS...
RADAR SHOWS ISOLATED SHOWERS ACROSS THE LOCAL AREA. SATELLITE SHOWS
PATCHY CLOUDS UPSTREAM APPROACHING 150E THAT ARE ASSOCIATED WITH
SURGING TRADE WINDS. A SHEAR LINE REMAINS STRETCHED ACROSS THE FAR
NORTHERN MARIANA ISLANDS WITH GALE FORCE WINDS NORTH OF THE SHEAR
LINE. LOCAL BUOYS REPORT SEAS 6 TO 7 FEET...MAINLY FROM EAST. VAD
GRADIENT WINDS ARE FROM EAST-NORTHEAST ABOUT 20 KT.

&&

.DISCUSSION...
MODELS INDICATE A PERIOD OF FRESH TO OCCASIONALLY STRONG TRADE WINDS
IS DEVELOPING ACROSS THE MARIANAS THAT WILL PERSIST THROUGH THE NEXT
WEEK OR MORE. SOME INCREASE IN CLOUDS AND A FEW SHOWERS ARE EXPECTED
AT TIMES THROUGH THIS WEEKEND.

&&

.MARINE...
SMALL CRAFT AND HIGH SURF ADVISORIES ARE LIKELY BY LATE FRIDAY OR
SATURDAY AS A TRADE-WIND SURGE ARRIVES...ALONG WITH A SIGNIFICANT
NORTHWEST SWELL. WW3 MODEL INDICATES GALE FORCE WINDS FAR TO OUR
NORTH WILL PRODUCE A NORTHWEST SWELL OF AT LEAST 4 OR 5 FEET THAT
WILL MOVE ACROSS THE REGION DURING THE COMING DAYS...ALONG WITH THE
BUILDING TRADE WIND SWELL AND WIND WAVES. WAVE GRIDS WERE ADJUSTED
ONLY SLIGHTLY AND WIND GRIDS WERE REFRESHED WITH LATEST GFS DATA.

&&

.EASTERN MICRONESIA...
SATELLITE IMAGERY SHOWS FAIR CONDITIONS ACROSS THE REGION WITH ONLY
SHALLOW TRADE-WIND CLOUDS AND ISOLATED SHOWERS. MORE SHOWERS ARE
SEEN NEAR THE DATE LINE IN THE PRESENCE OF TRADE-WIND CONVERGENCE.
THESE SHOWERS WILL GRADUALLY SHIFT WESTWARD AND REACH MAJURO FRIDAY
NIGHT AND KOSRAE SATURDAY NIGHT. LATER IN THE WEEK...STRONG HIGH
PRESSURE WILL PASS EASTWARD OVER THE NORTH PACIFIC. THIS WILL CAUSE
REGIONAL TRADE WINDS TO INCREASE IN RESPONSE TO INCREASING PRESSURE
GRADIENT. INCREASING SEAS MAY BECOME CAPABLE OF PRODUCING HAZARDOUS
SURF BY SUNDAY OR MONDAY. IN THE MEANTIME...NORTHWEST SWELL FROM A
STRONG COLD FRONT NORTHWEST OF THE MARIANAS CONTINUE TO ADVANCE TO
THE SOUTHEAST. THESE SWELL WILL REACH THE AREA FRIDAY OR SATURDAY.
THE COMBINATION OF NORTHWEST AND TRADE-WIND SWELLS WILL CAUSE CHOPPY
SEA CONDITIONS OVER THE WEEKEND AND NEXT WEEK. BY MIDWEEK...
INCREASING HIGH TIDES AND LARGE COMBINED SEAS WILL INCREASE THE RISK
OF INUNDATION ACROSS PORTIONS OF MAJURO...AND WE WILL CONTINUE TO
MONITOR FOR CHANGES IN MODEL DATA.

&&

.WESTERN MICRONESIA...
A WEAK CIRCULATION IS SEEN SOUTHWEST OF KOROR WITH A SURFACE TROUGH
EXTENDING SOUTHEASTWARD TOWARD THE EQUATOR. DISSIPATING SHOWERS AND
A FEW THUNDERSTORMS ARE FOUND NORTH OF THESE FEATURES AND CONTINUE
EASTWARD TOWARD ANOTHER WEAK CIRCULATION SOUTHWEST OF CHUUK NEAR
3N148E. THE BULK OF CONVECTION ASSOCIATED WITH THE CIRCULATION
SOUTHWEST OF CHUUK WILL DRIFT WESTWARD...HOWEVER MODELS KEEP MOST
ACTIVITY JUST SOUTH OF KOROR. DRIER WEATHER SEEN AT CHUUK AND YAP
WILL CONTINUE FOR MUCH OF THE NEXT SEVERAL DAYS.

HAZARDOUS SURF WILL PERSIST ACROSS THE REPUBLIC OF PALAU AND YAP
STATE THRU SATURDAY EVENING AS LARGE NORTH SWELLS PRODUCED BY GALE
FORCE WINDS BEHIND A COLD FRONT CONTINUE TO AFFECT THE REGION.
COMBINING WITH TRADE-WIND SWELLS AND WIND WAVES...SEAS WILL ALSO BE
HAZARDOUS FOR SMALL CRAFT UNTIL SUNDAY.

&&

.GUM WATCHES/WARNINGS/ADVISORIES...
GU...NONE.
MARIANAS WATERS...NONE.
&&

$$

SIMPSON/W. AYDLETT





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