Area Forecast Discussion
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FXPQ60 PGUM 012035 RRA
AFDPQ

AREA FORECAST DISCUSSION...RETRANSMITTED
NATIONAL WEATHER SERVICE TIYAN GU
626 AM CHST MON FEB 2 2015

RETRANSMITTED TO PLACE ON THE WEB

.SYNOPSIS...
A SHEAR LINE IS CURRENTLY PASSING SOUTHWARD OVER SAIPAN.
CONVECTION ASSOCIATED WITH THE NEAR-EQUATORIAL TROUGH IS CONFINED
WELL TO THE SOUTH OF GUAM BETWEEN THE EQUATOR AND 7N. LATEST
ASCAT/RAPIDSCAT ANALYSIS REVEALS A WEAK CIRCULATION CENTERED SOUTH
OF KOSRAE.

&&

.DISCUSSION...
ADDED MOSTLY CLOUDY SKIES FOR THIS AFTERNOON AND TONIGHT BASED ON
THE APPROACHING SHEAR LINE AND EXTENSIVE STRATOCUMULUS CLOUD COVER
EVIDENT ALONG AND NORTH OF THE BOUNDARY. KEPT POPS ISOLATED DURING
THE NEAR TERM AS MODELS KEEP QPF LOW AND OBSERVED SHALLOW DEPTH OF
THE STRATOCUMULUS. MODELS AGREE ON BRINGING THE SHEAR LINE SOUTH
OF GUAM...THEN SLOWLY BACKING IT UP TOWARD THE NORTH LATER IN THE
WEEK. REGION NORTH OF THE SHEAR LINE WILL BECOME WETTER AS
MOISTURE BEGINS TO OVERRUN THE BOUNDARY. FOR NOW...WILL INCREASE
CLOUD COVER THURSDAY NIGHT THROUGH SUNDAY. HOW MUCH RAINFALL
ACTUALLY OCCURS LATER ON IN THE WEEK DEPEND UPON IF/WHEN THE
TROPICAL DISTURBANCE PROGGED BY ALL THE MODELS DEVELOPS. SYSTEM
CURRENTLY CENTERED SOUTH OF KOSRAE DOES NOT APPEAR TO BE THE
SYSTEM THAT EVENTUALLY DEVELOPS...SO WILL TAKE A WAIT AND SEE
ATTITUDE WITH RESPECT TO FACTORING A TROPICAL DISTURBANCE INTO THE
FORECAST FOR THE SECOND HALF OF THE WEEK.

&&

.MARINE...
REDUCED BOTH TRADE-WIND AND NORTH SWELL TODAY AND TONIGHT BASED
ON THE LATEST BUOY READINGS FROM AROUND GUAM. COMBINED SEA
READINGS FROM THE RITIDIAN BUOY ARE BETWEEN 6 AND 7 FT...WHILE THE
IPAN BUOY COMES IN BETWEEN 5 AND 6 FEET. AFTER THESE CHANGES...
COMBINED SEAS ARE STILL EXPECTED TO FALL IN THE 7 TO 9-FOOT RANGE
TODAY THROUGH TUESDAY. WAVE WATCH MODEL BRINGS HIGHER NORTH SWELL
IN TONIGHT AND TUESDAY...WHICH COULD BRING COMBINED SEAS TO THE
SMALL CRAFT ADVISORY THRESHOLD. HAVE KEPT MARINE SWELL GRIDS ON
THE CONSERVATIVE SIDE DURING THE SECOND HALF OF THE FORECAST
PERIOD. IF MODEL AND SATELLITE TRENDS CONFORM THE DEVELOPMENT OF A
TROPICAL DISTURBANCE TO THE SOUTH OR SOUTHEAST OF GUAM...SWELL
HEIGHTS FOR THIS TIME FRAME MAY NEED TO BE INCREASED.

&&

.EASTERN MICRONESIA...
A NEAR EQUATORIAL TROUGH AND WEAK EMBEDDED CIRCULATION SOUTHEAST
OF KOSRAE WILL MAINTAIN ACTIVE WEATHER THROUGH MUCH OF THE WEEK
ACROSS POHNPEI AND KOSRAE STATES. MODELS ARE IN GOOD AGREEMENT IN
BRINGING PERIODS OF SCATTERED SHOWERS TO KOSRAE AND POHNPEI
THROUGH WEDNESDAY. THE POTENTIAL FOR HEAVY RAINFALL IS RISING...
ESPECIALLY FOR POHNPEI...AS MODEL RUNS BECOME INCREASINGLY MORE
AGGRESSIVE IN DEVELOPING THE CIRCULATION NOW SOUTHEAST OF KOSRAE
INTO A MORE SIGNIFICANT TROPICAL DISTURBANCE BY MIDWEEK. FOR
MAJURO...SHOWERS ASSOCIATED WITH A BAND OF TRADE- WIND CONVERGENCE
WILL AFFECT MAJURO THIS MORNING BEFORE DISSIPATING THIS AFTERNOON
OVER THE ATOLL. THE NEXT DISTURBANCE CURRENTLY APPROACHING THE
DATE LINE IS EXPECTED TO ARRIVE OVER THE MARSHALL ISLANDS LATE
TUESDAY. THIS SYSTEM WILL THEN AFFECT THE AREA THROUGH WEDNESDAY.

&&

.WESTERN MICRONESIA...
SATELLITE IMAGERY SHOWS A SMALL CLUSTER OF CONVECTION DEVELOPING
OVER PALAU WHICH WILL BRING SCATTERED SHOWERS TO KOROR WATERS
THROUGH THIS EVENING. STREAM LINE ANALYSIS SHOWS A SHEAR LINE
APPROACHING BOTH YAP AND KOROR. THIS BOUNDARY WILL PASS OVER YAP
WITHOUT MUCH EFFECT BUT SHOWERS OVER KOROR ASSOCIATED WITH THE
WEAK DISTURBANCE WILL LINGER INTO THIS EVENING WITH THE SHEAR LINE
AS REINFORCEMENT. THE SHEAR LINE...ATTENDANT SHOWERS AND NEAR-
EQUATORIAL TROUGH AXIS WILL SHIFT SOUTH OF KOROR TONIGHT. THIS
WILL ALLOW DRIER NORTHEAST FLOW TO ENTER THE REGION. CHUUK LIES
BETWEEN WEATHER FEATURES...A DIFFUSE SHEAR LINE TO THE NORTH AND
THE NEAR-EQUATORIAL TROUGH TO THE SOUTH. THE SHEAR LINE IS
EXPECTED TO SHIFT SOUTHWARD AND BRING LOW TO MID-LEVEL CLOUD COVER
TO CHUUK BUT SHOWERS THERE ARE EXPECTED TO REMAIN ISOLATED. MODELS
FURTHER DEVELOP THE WEAK CIRCULATION SOUTHEAST OF KOSRAE AND
EVENTUALLY BRING UNSETTLED CONDITIONS TO CHUUK LATE IN THE WEEK.

&&

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

$$

MCELROY/WILLIAMS



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