Area Forecast Discussion
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000
FXPQ60 PGUM 222119
AFDPQ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TIYAN GU
719 AM CHST TUE DEC 23 2014

.MARIANAS SYNOPSIS...EAST TRADE-WINDS AND A FEW SHOWERS PREVAILED
ACROSS THE MARIANAS THIS MORNING.

&&

.DISCUSSION...
ONLY A FEW TWEAKS MADE TO FORECAST. UPDATED THE WINDS WITH NEW
DATA IN A FEW SPOTS. ALL MODELS HINT AT A SMALL TRADE-WIND
DISTURBANCE PASSING ACROSS THE AREA TODAY. SATELLITE IMAGERY DOES
SHOW AN AREA OF CLOUDS TO THE EAST OF THE MARIANAS. SCATTEROMETER
DATA FROM LAST NIGHT HINTS AT A WEAK SURFACE TROUGH NEAR 150E.
EXPECT THIS TROUGH AND THESE CLOUDS TO MOVE WEST SO ADDED PARTLY
SUNNY TO THE FORECAST FOR TODAY. SHOWER COVERAGE SHOULD REMAIN
ISOLATED.

EAST TRADE-WINDS ARE EXPECTED TO INCREASE TODAY AS AN AREA OF
HIGH PRESSURE MOVES OFF OF ASIA. BREEZY CONDITIONS WITH WINDS OF
20 TO 25 MPH SHOULD PREVAIL THROUGH CHRISTMAS DAY. WINDS WILL
TAPER OFF BY FRIDAY.

&&

.MARINE...
AN EAST TRADE-WIND SWELL AND A NORTH SWELL WILL PERSIST THROUGH
THE FORECAST. BUOY DATA INDICATE SEAS NEAR GUAM AND SAIPAN AROUND
9 FEET. SATELLITE ALTIMETRY SHOWS SEAS BETWEEN 10 TO 12 FEET OVER
THE MARIANAS. WINDS SHOULD INCREASE TO SMALL CRAFT LEVEL DURING
THE DAY. SEAS ARE ALREADY HIGH ENOUGH FOR SMALL CRAFT ADVISORY.
MODELS KEEP THE WINDS AND SEAS WITHIN SMALL CRAFT CRITERIA THROUGH
AT LEAST FRIDAY.

&&

.EASTERN MICRONESIA...
A WEAK CIRCULATION IS SEEN NEAR 2N156E...SOUTH-SOUTHWEST OF
POHNPEI. SHOWERS AND THUNDERSTORMS ARE FOUND TO THE SOUTH OF IT
NEAR THE EQUATOR AND TO THE NORTH NEAR POHNPEI AND KOSRAE.
NUMEROUS HEAVY SHOWERS WILL PERSIST AT POHNPEI FOR THE
MORNING...BECOMING SCATTERED THIS AFTERNOON. ANOTHER AREA OF
SHOWERS AND THUNDERSTORMS IS SEEN JUST MOVING TO THE WEST OF
MAJURO. DRIER CONDITIONS ARE EXPECTED AT MAJURO BY THIS AFTERNOON
AND WILL REMAIN THROUGH THE WEEK. MODELS INDICATE THIS ACTIVE
PATTERN OF SHOWERS AND THUNDERSTORMS WILL CONTINUE AT KOSRAE
THROUGH WEDNESDAY AND AT POHNPEI THROUGH TONIGHT.
AFTERWARDS...DRIER NORTHEAST TRADES WILL SUPPRESS CONVECTION
FARTHER SOUTH.

HIGH SURF ADVISORIES AND WARNING CONTINUE ACROSS THE REGION.
SWELL AND SURF ARE EXPECTED TO PEAK AROUND MIDWEEK THEN BEGIN A
SLOW DECREASE LATER IN THE WEEK. MAJURO AND ARNO COULD STILL SEE
SOME INUNDATION AROUND TIMES OF HIGH TIDES. MORE IN-DEPTH
INFORMATION CAN BE FOUND IN THE COASTAL HAZARD MESSAGE UNDER WMO
HEADER WHPQ40 PGUM.

&&

.WESTERN MICRONESIA...
AT THE MOMENT ALL THREE LOCATIONS REMAIN FAIRLY DRY WITH
SCATTERED HIGH-LEVEL CLOUDS SEEN OVER CHUUK STATE...BUT A WEAK
CIRCULATION SOUTH-SOUTHEAST OF CHUUK WILL DRIFT WESTWARD SLOWLY
AND BRING SHOWERS AND THUNDERSTORMS INTO THE REGION. SATELLITE
IMAGERY SHOWS CONVECTION NEAR POHNPEI RAPIDLY MOVING WEST SO HAVE
ADJUSTED CHUUK FORECAST WITH AN EXPECTED ARRIVAL OF WET WEATHER
THIS AFTERNOON AND CONTINUING THROUGH WEDNESDAY NIGHT. MODEL
CONSENSUS BRINGS THIS DISTURBANCE TOWARD YAP AND KOROR BY
THURSDAY WITH NAVGEM KEEPING THE FOCUS OF CONVECTION JUST NORTH
OF YAP...VERSUS THE ECMWF CLOSER TO KOROR AND GFS AND THE MIDDLE.
TIMING OF SHOWERS DIFFERS SLIGHTLY BETWEEN THE MODELS HOWEVER
SCATTERED SHOWERS SHOULD BE EXPECTED BY THURSDAY AT BOTH
LOCATIONS. FRIDAY AND SATURDAY WILL BE SLIGHTLY DRIER AS TRADES
BEGIN TO BECOME BETTER ESTABLISHED ACROSS THE AREA.

HIGH SURF ADVISORY REMAINS IN EFFECT AT CHUUK FOR THE NEXT FEW
DAYS. SURF WILL BUILD ACROSS YAP AND KOROR AROUND MIDWEEK AS THE
DISTURBANCE APPROACHES. HOWEVER...WITH DIFFERING MODEL
WINDS...STILL HAVE LOW CONFIDENCE ON WHETHER OR NOT SEAS WILL
BUILD ENOUGH TO GENERATE HAZARDOUS SURF ALONG EAST FACING REEFS
WEDNESDAY OR THURSDAY.

&&

.GUM WATCHES/WARNINGS/ADVISORIES...
GU...NONE.
MARIANAS WATERS...SMALL CRAFT ADVISORY UNTIL 6 AM CHST FRIDAY FOR PMZ151>154.

&&

$$

ZIOBRO/W. AYDLETT





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