Subject: Western Pacific: Synoptic Discussion For The Marianas

From: LDM Weather <[email-masked]>
Date: Mon, 6 Dec 2010 01:11:00 -0600

524 
FXPQ60 PGUM 060710
AFDPQ 

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TIYAN GU
510 PM CHST MON DEC 6 2010

.SYNOPSIS...
A WEAKENING SHEAR LINE SHIFTED NORTHWARD JUST FAR ENOUGH TO BRING
MOSTLY CLOUDY CONDITIONS AND A SLIGHTLY HIGHER CONCENTRATION OF
SHOWERS TO GUAM AND ROTA THAN ISLANDS FARTHER NORTH. LATEST UPPER-
AIR SOUNDING INDICATES VERY DRY MID AND UPPER-LEVELS WITH WV SAT
IMAGERY SHOWING AN EXPANSIVE DRY REGION BETWEEN 8N AND 20N FROM
THE MARIANAS TO THE DATE LINE. 

&&

.DISCUSSION...
ALTHOUGH THE SHEAR LINE DID DRIFT NORTHWARD TODAY...SCATTERED
SHOWERS DID NOT QUITE DEVELOP ACROSS THE AREA. GFS CONTINUES TO
DEPICT A VERY NARROW E-W BAND OF CONVECTION THAT WILL MEANDER
NEAR GUAM THROUGH WEDNESDAY WHILE GFSE...UKMET AND ECMWF TAKE THE
DRY ROAD...KEEPING CONDITIONS DRY ACROSS THE MARIANAS. DECIDED TO
LIMIT THE DIFFERENCE IN WEATHER BETWEEN THE SOUTHERN AND NORTHERN
ZONES TO THAT OF CLOUD COVER FOR TONIGHT...WITH FEWER CLOUDS IN
THE NORTH. SURFACE RIDGING WILL BEGIN TO DROP IN FROM THE NORTH
BY LATE TOMORROW AND FURTHER SUPPRESS DEEP CONVECTION THROUGH THE
WEEKEND.

&&

.MARINE...
ALTIMETRY DATA SHOWS 8 TO 12 FT SEAS WELL NORTHEAST OF THE
MARIANAS AND NORTH OF WAKE ISLAND AND SLOWLY EXPANDING WEST-
SOUTHWESTWARD. WAVEWATCH MODELS INITIALIZE WELL WITH THE REGION
OF LARGE SWELL AND EXPANSION...BUT STOP SHORT OF BRINGING LARGE
NE SWELL TO THE MARIANAS...SO AT THE MOMENT A HIGH SURF ADVISORY
IS NOT ANTICIPATED FOR NORTH AND EAST FACING SHORES. A SMALL
NORTHWEST SWELL WILL ENTER THE REGION LATE THIS WEEK AS A FRONTAL
SYSTEM DROPS SOUTHEASTWARD FROM JAPAN.

&&

.EASTERN MICRONESIA...
A WEAK TROUGH IN THE TRADE WINDS JUST WEST OF KWAJALEIN IS
EXPECTED TO CONTINUE TO PUSH OUT OF THE AREA TODAY LEAVING ALL
THREE LOCATIONS WITH MOSTLY DRY CONDITIONS FOR THE NEXT SEVERAL
DAYS. LATEST WATER VAPOR SHOWS A PRETTY DRY TROPOSPHERE BETWEEN
YAP AND THE DATELINE AND NORTH OF 10N LATITUDE AND SO THIS SEEMS
TO FIT IN WITH ALL NWPS SHOWING LITTLE PRECIPITATION AND ONLY A
SLIGHT INCREASE IN CLOUDINESS BY THE END OF THE WEEK. THE WAVE
WATCH3 MODEL CONTINUES TO SHOW A SLIGHT INCREASE IN SEAS BY
WEDNESDAY OR THURSDAY...BUT A CALCULATION OF SURF SHOWS THAT ALL
AREAS...INCLUDING KOSRAE... SHOULD REMAIN BELOW HIGH SURF
CRITERIA. OVERALL...LITTLE CHANGE FROM THE PREVIOUS FORECAST.

&&

.WESTERN MICRONESIA...
WEATHER FOR YAP AND CHUUK DURING THIS FORECAST PERIOD FOLLOWS
ALONG THE ABOVE SCENARIO FOR EASTERN MICRONESIA WITH LITTLE
CHANCE OF SIGNIFICANT PRECIPITATION. THE AREA OF SHOWERS SOUTH OF
CHUUK LOOKS LIKE IT WILL HAVE LITTLE EFFECT TO CHUUK EXCEPT FOR
SOME OCCASIONAL UPPER-LEVEL CLOUDINESS. CONDITIONS FOR YAP ALSO
LOOK PRETTY DRY...LEAVING ONLY PALAU WITH ANY SIGNIFICANT WEATHER
AS IT REMAINS WITHIN THE TRADE-WIND TROUGH THAT EXTENDS EAST OF
THE SOUTHERN PHILIPPINES. MODEL GUIDANCE KEEPS PALAU WITHIN THIS
PATTERN FOR THE NEXT SEVERAL DAYS BUT THE MOST RECENT NWP MODEL
RUNS KEEP THE WEATHER SOUTH OF YAP. WW3 SHOWS SEAS REMAINING AT 5
TO 6 FT FOR YAP AND PALAU WITH THE POSSIBILITY OF A WEAK
NORTHEASTERLY SWELL AFFECTING CHUUK BY MID WEEK...BUT STILL WELL
BELOW HIGH SURF CRITERIA.

&&

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

$$

W. AYDLETT/EDSON

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