Area Forecast Discussion
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FXPQ60 PGUM 292117
AFDPQ

AREA FORECAST DISCUSSION...RETRANSMITTED
NATIONAL WEATHER SERVICE TIYAN GU
712 AM CHST FRI JAN 30 2015

RETRANSMITTED FOR WEB ACCESS

.SYNOPSIS...
A WEAKENING SHEAR LINE PASSES THROUGH THE NORTHERN CNMI NEAR
ANATAHAN. DEEP CONVECTION ASSOCIATED WITH THE NEAR-EQUATORIAL
TROUGH AND A WEAK CIRCULATION CENTERED JUST SOUTHWEST OF KOSRAE
COVERS A LARGE AREA BETWEEN CHUUK AND MAJURO. PARTLY CLOUDY SKIES
AND ISOLATED SHOWERS CURRENTLY RESIDE OVER THE FORECAST ZONES.

&&

.DISCUSSION...
FORECAST CLOSELY FOLLOWS PERSISTENCE. NO FORECAST GRID
ADJUSTMENTS WERE NECESSARY. STILL EXPECT SHOWERS AND CLOUDINESS
ASSOCIATED WITH THE NEAR-EQUATORIAL TROUGH TO REMAIN SOUTH OF GUAM
THROUGH THE FORECAST PERIOD. HOWEVER...CLOUDS AND SHOWERS COULD
SPREAD FAR ENOUGH TO THE NORTH TO REACH GUAM SATURDAY THROUGH
SUNDAY. WILL MAINTAIN A DRY BIAS FOR NOW AS BOTH MODEL AND
SATELLITE TRENDS SUPPORT THIS FORECAST SCENARIO. SHEAR LINES WILL
BE MOVING THROUGH THIS WEEKEND AND ON MONDAY OR TUESDAY...BUT
CLOUD AND SHOWER COVERAGE LOOKS LIMITED.

&&

.MARINE...
REDUCED TRADE-WIND SWELL HEIGHTS FOR TODAY AND TONIGHT BY 1 FOOT
BASED ON THE LATEST READINGS FROM THE IPAN AND RITIDIAN BUOYS.
STILL EXPECT LOW PRESSURE PASSING SOUTH OF GUAM TO COMBINE WITH
HIGH PRESSURE BUILDING NEAR JAPAN TO TIGHTEN THE SURFACE PRESSURE
GRADIENT OVER THE FORECAST ZONES NEXT WEEK. WINDS AND SEAS WILL BE
BUILDING DURING THIS TIME FRAME. A NORTH SWELL COULD CAUSE SEAS TO
BUILD TO ADVISORY HEIGHTS BY TUESDAY.

&&

.EASTERN MICRONESIA...
A ZONE OF LOW-LEVEL CONVERGENCE EXISTS ALONG THE LEADING EDGE OF
STRONGER TRADE WINDS FROM SOUTH OF THE MARSHALL ISLANDS EXTENDING
INTO KOSRAE STATE. SATELLITE IMAGERY SHOWS WIDESPREAD DEEP
CONVECTION CONTINUING TO DEVELOP SOUTHWEST OF MAJURO AND OVER
KOSRAE. MODELS MAINTAIN AN ACTIVE WEATHER PATTERN OVER KOSRAE
THROUGH AT LEAST TONIGHT BEFORE TAPERING CONVECTION OFF SATURDAY.
MAJURO HAS ESCAPED MOST OF THE SHOWERS ASSOCIATED WITH THIS
FEATURE BUT HIGH CLOUD COVER FROM CONVECTION FARTHER SOUTH WILL
PERSIST OVER THE ATOLL THROUGH TONIGHT. THE CONVERGENCE ZONE AND
ASSOCIATED CONVECTION WILL PUSH NORTHWARD OVER THE NEXT 24 HOURS
AND BRING SCATTERED SHOWERS AND SOME THUNDERSTORMS TO POHNPEI
BEGINNING LATER TODAY OR TONIGHT. CONDITIONS ARE EXPECTED TO
IMPROVE ACROSS EASTERN MICRONESIA NEXT WEEK AS DRY NORTHEAST TRADE
WINDS RETURN TO THE REGION.

TRADE-WIND WAVES AND SWELL HAVE PEAKED ACROSS KOSRAE STATE AND
THE MARSHALL ISLANDS. SURF IS EXPECTED TO STEADILY FALL TODAY ON
EAST FACING REEFS OF MAJURO AND KOSRAE THROUGH TONIGHT. SURF
SHOULD SUBSIDE BELOW HAZARDOUS LEVELS ON KOSRAE BY SATURDAY AND ON
MAJURO BY THIS AFTERNOON.

&&

.WESTERN MICRONESIA...
SATELLITE SHOWS DEEP CONVECTION REMAINING CONFINED TO THE
SOUTHEAST OF CHUUK. MODELS PIVOT A CIRCULATION AND ATTENDANT
TROUGH CURRENTLY SOUTHWEST OF KOSRAE TOWARD THE NORTHWEST TONIGHT.
ASSOCIATED CONVECTION WILL PASS SOUTH OF POHNPEI AND HEAD TOWARD
CHUUK. GFS BRINGS A NARROW LINE OF SHOWERS JUST SOUTH OF CHUUK
TONIGHT. SHORT TERM FORECAST CONFIDENCE FOR THIS FEATURE IS LOW SO
ONCOMING SHIFT WILL HAVE TO ASSESS SUBSEQUENT MODEL RUNS. IN THE
LONG TERM...A DRIER TREND IS PROGGED TO BEGIN NEXT WEEK ON CHUUK
AS THE NEAR-EQUATORIAL TROUGH RETREATS SOUTHWARD. DRY NORTHEAST
FLOW WILL CONTINUE ON YAP AND KOROR THROUGH SATURDAY NIGHT. A
SHEAR LINE IS EXPECTED TO APPROACH YAP AND KOROR SUNDAY AND
MONDAY. GUIDANCE SUGGESTS SHOWER COVERAGE WILL BE LIMITED
ACCOMPANYING THIS FEATURE SO KEPT ISOLATED WORDING FOR EARLY NEXT
WEEK. WINDS NORTH OF THE SHEAR LINE WILL GENERATE CONSIDERABLE
SWELL AND WAVES FOR YAP AND KOROR SO INCREASED SEAS SLIGHTLY NEXT
WEEK AS THE SIGNAL IN THE NUMERICAL MODELS IS A BIT STRONGER.

&&

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

$$

MCELROY/WILLIAMS



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