Subject: Western Pacific: Synoptic Discussion For The Marianas

From: LDM Weather <[email-masked]>
Date: Sun, 20 Jan 2008 13:43:42 -0600

747 
FXPQ60 PGUM 201943
AFDPQ 

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TIYAN GU
543 AM CHST MON JAN 21 2008

.SYNOPSIS...
A SHEAR LINE CAN BE OBSERVED IN BOTH RADAR AND IR SATELLITE
IMAGERY BETWEEN ANATAHAN AND SAIPAN. A REINFORCING PUSH OF COLDER
AIR IS PUSHING SOUTHWARD FROM AROUND 22N TOWARD THE NORTHERNMOST
MARIANAS.

&&

.DISCUSSION...
MODEL RUNS STILL SUGGEST SHEAR LINE WILL REMAIN EMBEDDED IN HOSTILE 
DIVERGENT LOW-LEVEL FLOW AS IT FILTERS THROUGH MONDAY AND TUESDAY. 
MODELS QPFS ALL LOOK LOW DURING THE NEXT COUPLE OF DAYS...SO BELIEVE 
MOSTLY CLOUDY/ISOLATED WORDING REMAINS THE OPTIMAL FORECAST 
SOLUTION. MODELS SUGGEST VERY DRY AND BRISK FLOW FROM THE NORTHEAST 
WILL FOLLOW IN THE WAKE OF THE SHEAR LINE. GFS TIME-HEIGHT CROSS 
SECTION SHOWS VERY SHALLOW LOW-LEVEL MOISTURE TO ONLY 850 MB 
THURSDAY THROUGH SUNDAY. CONFIDENCE IS HIGHER FOR NO WEATHER OR 
SLIGHT CHANCE POP GRIDS THURSDAY THROUGH SATURDAY...SO WILL EDIT THE 
GRIDS ALONG THESE LINES FOR NOW.

&&

.EASTERN MICRONESIA...
A WEAK TRADE-WIND DISTURBANCE IS CURRENTLY MOVING TOWARD KOSRAE AND 
POHNPEI. ISOLATED SHOWERS WILL BECOME SCATTERED THIS EVENING AND
LAST INTO TUESDAY. MAJURO IS UNDER THE INFLUENCE OF DRY TRADE WINDS
AND BENIGN WEATHER WILL CONTINUE THROUGH THE FORECAST PERIOD.
THIS SAME WEATHER PATTERN WILL OVERSPREAD POHNPEI AND KOSRAE BY
TUESDAY NIGHT.

LATEST WAVE WATCH GUIDANCE INDICATES SURF ALONG NORTH FACING
SHORES ON CHUUK AND POHNPEI HAS RISEN TO THE ADVISORY LEVEL OF 9
FT AND WILL PERSIST THROUGH TUESDAY. THEREFORE...ISSUED HIGH SURF
ADVISORY FOR BOTH ISLANDS.

&&

.WESTERN MICRONESIA...
A NEAR-EQUATORIAL TROUGH RUNS SOUTH OF KOROR AND YAP...THEN LINKS
TO A WEAK CIRCULATION SOUTH OF CHUUK. MOST MODELS EXCEPT THE ECMWF
ARE KEEPING MOST OF THE ACTION ASSOCIATED WITH THIS SYSTEM SOUTH
OF ALL THE MAJOR ISLANDS. SOME CLOUDINESS AND ISOLATED SHOWERS
WILL SPREAD OVER PALAU AND CHUUK FROM TIME TO TIME THROUGH
WEDNESDAY. YAP IS FAR ENOUGH NORTH NOT TO BE AFFECTED THROUGH THE
PERIOD. STRONG HIGH PRESSURE COMING OFF THE ASIAN CONTINENT WILL
STRENGTHEN TRADE WINDS ACROSS PALAU AND YAP AFTER MID-WEEK.

&&

.MARINE...
WINDS...SEAS AND WAVES ARE STILL THE ELEPHANTS IN THE ROOM AS FAR AS 
FORECAST CONCERNS GO. ALTIMETRY FOR THE WESTERN PACIFIC STILL 
REMAINS UNAVAILABLE...SO FORECAST TOOLS ARE LIMITED TO THE IPAN BUOY 
AND WAVE WATCH MODEL DATA. INHERITED HAZARD GRIDS LOOKED GOOD AND 
PRESENT CONSERVATIVE SOLUTIONS REGARDING THE SMALL CRAFT AND HIGH
SURF ADVISORIES. WILL GO AHEAD AND HANG ON TO BOTH OF THESE UNTIL
TUESDAY...ALTHOUGH WAVE WATCH TABULAR DATA SUGGEST COMBINED SEAS
WILL DROP BELOW 10 FEET BEFORE SURF SUBSIDES BELOW 9 FEET ON NORTH
FACING REEFS.

&&

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

MARIANAS WATERS...SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 6
PM CHST TUESDAY FOR PMZ151>154.

&&

$$

MCELROY/CHAN

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