Subject: Western Pacific: Synoptic Discussion For The Marianas

From: LDM Weather <[email-masked]>
Date: Tue, 29 Jan 2008 01:51:20 -0600

479 
FXPQ60 PGUM 290751
AFDPQ 

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TIYAN GU
551 PM CHST TUE JAN 29 2008

.SYNOPSIS...
SHEAR LINE IS STILL HOVERING JUST NORTH OF SAIPAN...WITH VIRTUALLY 
CLOUDLESS SKIES SOUTHWARD TO AROUND 12N. A NUMBER OF TRADE-WIND 
DISTURBANCES ARE VISIBLE UPSTREAM...BUT NONE OF THESE APPEAR LARGE 
ENOUGH OR WET ENOUGH TO JUSTIFY SCATTERED FORECAST WORDING. VAD WIND 
PROFILE SHOWS GRADIENT-LEVEL WIND HAS CREPT UP ABOUT 5 KNOTS DURING 
THE PAST 12 HOURS...EVIDENCE THAT THE TRADE-WIND SURGE ADVERTISED BY 
THE MODELS DURING THE PAST WEEK OR SO IS ARRIVING.

&&

.DISCUSSION...
ECMWF AND GFS BOTH HINT AT A COUPLE OF TIGHTLY BUNCHED TRADE-WIND 
DISTURBANCES MOVING THROUGH ON THURSDAY AND FRIDAY. WILL HOLD OFF ON 
SCATTERED WORDING PER SYNOPSIS...BUT WILL INTRODUCE MOSTLY CLOUDY 
SKIES INTO THE GRIDS. WINDS AND SEAS REMAIN THE TOP STORY. SEE 
MARINE DISCUSSION SECTION FOR MORE DETAILS.

&&

.EASTERN MICRONESIA...
TRADE-WIND CONVERGENCE AHEAD OF A TRADE SURGE WILL KEEP
CLOUDINESS AND SOME SHOWERS OVER KOSRAE AND POHNPEI THROUGH
TONIGHT. MORE STABLE AIR AT THE SURFACE ALONG WITH UPPER-LEVEL
SUBSIDENCE WILL CLEAR THINGS OUT WEDNESDAY INTO THURSDAY NIGHT.
CLOUDS ARE EXPECTED TO INCREASE BY EARLY WEDNESDAY MORNING ON
MAJURO AS A TRADE-WIND DISTURBANCE APPROACHES. THE MODELS ARE
TRYING TO INTENSIFY THE DISTURBANCE OVER THE MARSHALLS ON
THURSDAY AND FRIDAY...THEN SPREAD IT INTO KOSRAE AND POHNPEI OVER
THE WEEKEND. DECIDED NOT TO JUMP ON THE WORST CASE SCENARIO AT
THIS TIME. FORECASTERS WILL THUS HAVE MORE ROOM FOR ADJUSTMENTS
ON THE UPCOMING SHIFTS.

COMPUTER GUIDANCE CONTINUES TO INDICATE HAZARDOUS SURF ALONG NORTH 
FACING SHORES THRU WEDNESDAY MORNING FOR CHUUK...POHNPEI AND KOSRAE. 
SURF WILL GRADUALLY SUBSIDE BELOW ADVISORY LEVELS BY EARLY THURSDAY
MORNING.

&&

.WESTERN MICRONESIA...
SCATTERED SHOWERS WILL LINGER OVER CHUUK INTO WEDNESDAY MORNING
BUT DRIER WEATHER WILL ARRIVE FROM THE EAST BY WEDNESDAY EVENING.
A TRADE DISTURBANCE CURRENTLY APPROACHING MAJURO MIGHT AFFECT
CHUUK OVER THE WEEKEND BUT IT IS TOO EARLY TO TELL. LATEST MODEL
RUNS INDICATE BOTH PALAU AND YAP WILL ENJOY A DRY TRADE-WIND
REGIME THROUGH THE FORECAST PERIOD. TRADE-WIND CONVERGENCE WILL
BE CONFINED CLOSE TO THE EQUATOR...SPARING YAP AND PALAU
SCATTERED SHOWERS.

&&

.MARINE...
WAVE WATCH BRINGS COMBINED SEAS UPWARD FROM 8 FEET TO AROUND 9 FEET 
BY WEDNESDAY EVENING. IPAN BUOY HAS TRENDED UPWARD ABOUT A FOOT 
DURING THE PAST DAY. NORTH SWELL APPEAR TO BE SUBSIDING SLOWER THAN 
EARLIER FORECAST. THIS...ALONG WITH THE ARRIVING TRADE-WIND SURGE... 
WILL BRING COMBINED SEAS VERY CLOSE TO THE SCA THRESHOLD OF 10 FEET 
WEDNESDAY AND THURSDAY. WENT AHEAD AND BIT THE BULLET ON THE SCA 
BASED ON THIS AND REPORTS OF ROUGH SEAS AT THE AGANA BOAT BASIN 
ENTRANCE. ONE TREND OF NOTE IS THAT NORTH SWELL ENERGY GETS SWAPPED 
FOR TRADE-WIND ENERGY DURING THE COURSE OF THIS WEEK...WITH COMBINED 
SEAS REMAINING NEARLY CONSTANT. 

&&

.GUM WATCHES/WARNINGS/ADVISORIES...
GU...HIGH SURF ADVISORY UNTIL 6 AM CHST WEDNESDAY FOR GUZ001>004.

MARIANAS WATERS...SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS FROM 6 AM WEDNESDAY TO 6 
     AM CHST THURSDAY FOR PMZ151>154.

&&

$$

MCELROY/CHAN

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