Subject: Western Pacific: Synoptic Discussion For The Marianas

From: LDM Weather <[email-masked]>
Date: Wed, 02 Jan 2008 14:04:33 -0600

571 
FXPQ60 PGUM 022004
AFDPQ 

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TIYAN GU
604 AM CHST THU JAN 3 2008

.SYNOPSIS...
SWELLS FROM THE EAST AND NORTHWEST WILL CONTINUE TO COMBINE TO
PRODUCE COMBINED SEAS GREATER THAN SMALL CRAFT ADVISORY CRITERIA.
THE NORTHWEST SWELL WILL ALSO PRODUCE HAZARDOUS SURF ALONG NORTH
AND WEST FACING REEFS. OTHERWISE...WSR-88D AND SATELLITE IMAGERY
BOTH SHOW ISOLATED SHOWERS IN THE AREA OF THE MARIANAS.

&&

.DISCUSSION...
LITTLE CHANGE FROM PREVIOUS FORECAST PACKAGE AS SHEAR LINE IS
STILL EXPECTED TO REMAIN NORTHWEST OF OUR AREA. SINCE WINDS DID
DECREASE THIS MODEL RUN...AS MENTIONED IN THE SHIFT BRIEF...WENT
AHEAD AND COBBLED DAYS 8 THROUGH 10 OF THE 06Z MODEL WINDS INTO
THE FORECAST. THIS RESULTED IN LITTLE CHANGE OVER THE LAND BUT A
DECREASE OVER THE WATER. IT ALSO EXTENDED AVAILABLE WIND GRIDS BY
SEVERAL HOURS. BEFORE DAY 8...ONLY MINOR CHANGES SO IT DID NOT
SEEM WORTHWHILE.

MORE DRY WEATHER APPEARS TO BE ON TAP. ECMWF HI-RES ATTEMPTS TO
DUMP ABOUT A THIRD OF AN INCH OF RAIN ON OUR AREA...BUT IT SEEMS
TO SPRING UP SUDDENLY RIGHT OVER US THEN DISAPPEAR JUST AS QUICKLY
SO DISCOUNTED THIS SCENARIO AT THIS TIME. LOOK FOR ANOTHER 7 DAYS
OF PARTLY CLOUDY WITH BELOW NORMAL SHOWER ACTIVITY.

&&

.MARINE...
ADDED A SMALL CRAFT ADVISORY FOR SEAS DUE TO THE CONVERGENCE OF
TWO RATHER BEEFY SWELLS AND SOME WIND WAVES. IPAN BUOY SHOWS 7.5
FEET BUT IS SHIELDED FROM THE NORTHWEST SWELL. THE ADVISORY IS
PROBABLY RATHER BORDERLINE TODAY...BUT FURTHER INCREASES ARE
EXPECTED TONIGHT...SO WENT AHEAD AND ISSUED IT NOW.

&&

.EASTERN MICRONESIA...
WITH THE HELP OF AN UPPER-LEVEL TROUGH STRETCHING ACROSS POHNPEI
THEN NORTH OF KOSRAE AND THE MARSHALL ISLANDS...SCATTERED SHOWERS
WITH LOW CLOUD TOPS ARE FORMING ACROSS MUCH OF THE AREA THIS
MORNING. THESE SHOWERS WILL DECREASE IN COVERAGE STARTING THIS
EVENING INTO EARLY FRIDAY MORNING AS INFLUENCE FROM THE UPPER
TROUGH DIMINISHES. SUBSIDENCE ASSOCIATED WITH AN UPPER HIGH OVER
THE MARIANAS SHALL THEN SPREAD EASTWARD SUPPRESSING SHOWER
FORMATION INTO THE WEEKEND. HOWEVER A SURFACE TROUGH EAST OF THE
DATELINE MIGHT BRING SOME SHOWERS TO THE MARSHALL ISLANDS OVER THE
WEEKEND.

LATEST MODEL GUIDANCE SUGGESTS SURF ALONG NORTHEAST AND EAST FACING 
REEFS ON MAJURO AND KOSRAE REACHING WARNING AND ADVISORY LEVELS 
RESPECTIVELY. THIS EVENT WILL LIKELY LAST THROUGH SATURDAY FOR BOTH 
ISLANDS WITH MAJURO BACKING DOWN TO ADVISORY LEVEL BY FRIDAY 
AFTERNOON. ISSUED WARNING AND ADVISORY ACCORDINGLY.

&&

.WESTERN MICRONESIA...
THE WEAK TRADE-WIND DISTURBANCE HAS PASSED YAP AND MERGED INTO THE 
NEAR-EQUATORIAL TROUGH SOUTH OF PALAU. WITH THIS TROUGH EXPECTED TO 
REMAIN SOUTH OF 5N MODERATE TRADES WILL DOMINATE BOTH STATES THROUGH 
THE FORECAST PERIOD. EVEN WITH THE UPPER TROUGH OVER CHUUK THIS 
MORNING...SURFACE CONVERGENCE IS JUST TOO WEAK TO GENERATE ANY 
ORGANIZED SHOWER ACTIVITY. AS THE UPPER TROUGH BEING TAKEN OVER BY 
AN UPPER HIGH TONIGHT...RELATIVELY DRY WEATHER WILL REMAIN INTO THE 
WEEKEND.

CONTINUE HIGH SURF ADVISORY FOR BOTH PALAU AND YAP THROUGH SATURDAY 
BASED ON COMPUTER MODEL OUTPUT.

&&

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

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

&&

$$

STANKO/CHAN

+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
To unsubscribe from WX-TROPL send e-mail to [email-masked] with
"unsub wx-tropl" in the body of your message. For help with WX-TROPL
write to [email-masked]. For more information on tropical weather products, see the NHC Homepage at http://www.nhc.noaa.gov.