Subject: Western Pacific: Synoptic Discussion For The Marianas

From: LDM Weather <[email-masked]>
Date: Fri, 25 Jan 2008 01:22:43 -0600

279 
FXPQ60 PGUM 250722
AFDPQ 

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TIYAN GU
522 PM CHST FRI JAN 25 2008

.SYNOPSIS...
PGUA WSR-88D SHOWS ONLY A FEW LIGHT SPRINKLES IN THE AREA OF THE
MARIANAS. HOWEVER...A WELL DEVELOPED BUTTERFLY PATTERN SHOWS
RATHER ROBUST TRADE WINDS HAVE MOVED IN.

&&

.DISCUSSION...
GFS40 MODEL INDICATES THAT THESE TRADE WINDS ARE LOCATED JUST
SOUTH OF A SHEAR LINE...AND THAT THEY SHOULD STAY IN THE AREA
THROUGH NEXT WEEK. ECMWF HI-RES IS LARGELY IN AGREEMENT WITH THIS
SCENARIO...SO IT LOOKS LIKE WIND WILL BE THE MAJOR FORECAST STORY
THIS PACKAGE. THEREFORE...REFRESHED THE WINDS FROM THE LATEST
MODEL RUN SO THE PACKAGE CONTAINS THE LATEST AND GREATEST DATA.
THESE LATEST RUNS STILL UNDERESTIMATED THE WINDS TODAY...SO IT
WILL BE QUITE INTERESTING TO SEE WHAT HAPPENS SATURDAY. THE WINDS
MAY NEED TO BE BEEFED UP EVEN FURTHER.

FOR THE MOST PART...MODELS ARE IN AGREEMENT THAT THERE WILL BE NO
SIGNIFICANT WETTING RAINS THROUGH THE FORECAST PERIOD. THEREFORE
KEPT ISOLATED SHOWER WORDING. INCREASED THE CLOUDS A LITTLE
SATURDAY AS SOME CLOUDINESS AHEAD OF THE SHEAR LINE SEEMS TO BE
MOVING IN...BUT ON THE WHOLE PREVIOUS PACKAGE WAS STILL IN FINE
SHAPE.

&&

.MARINE...
COMBINATION OF NORTHEASTERLY WIND WAVES AND NORTHERLY SWELL WILL
PRODUCE HAZARDOUS SURF STARTING SATURDAY MORNING. THE SURF WILL
LIKELY LAST THROUGH TUESDAY MORNING. THE WIND WAVES WILL ALSO
DRIVE COMBINED SEAS UP TO A POINT WHERE SMALL CRAFT ADVISORY
CRITERIA MIGHT BE EXCEEDED. THIS PROBABLY WOULD NOT HAPPEN TIL
SUNDAY...SO WILL LEAVE THAT QUESTION FOR SOMETIME ON SATURDAY.

&&

.FIRE WEATHER...
THIS COMBINATION OF ONGOING LOW RAIN AND INCREASING WIND MAY ALSO
SPELL AN INTERESTING TIME FOR FIRE WEATHER. THE KEETCH-BYRAM
DROUGHT INDEX IS ALREADY HIGH...AND SHOULD BECOME EXTREME NEXT
WEEK. WITH THE WINDS ADDED IN WE COULD END UP WITH A RED FLAG
WARNING. HOPEFULLY NO FIRES WILL BE ACTIVELY BURNING.

&&

.EASTERN MICRONESIA...
NO CHANGE IN FORECAST DISCUSSION...A DRY TRADE REGIME WILL 
CONTINUE TO KEEP MOST OF EASTERN MICRONESIA UNDER PARTLY CLOUDY 
SKIES WITH ONLY ISOLATED SHOWERS THROUGH EARLY NEXT WEEK. MODELS 
HINT AT VERY LITTLE IN THE WAY OF SIGNIFICANT WEATHER PRODUCERS 
THROUGH THE WEEKEND. HOWEVER...WW3 OUTPUT DOES CONTINUE TO SUGGEST 
THAT SURF WILL ONCE AGAIN REACH HAZARDOUS LEVELS FOR MOST OF THE
REGION BY MONDAY OR TUESDAY.

&&

.WESTERN MICRONESIA...
LITTLE CHANGE IN DISCUSSION...THE NEAR-EQUATORIAL TROUGH WILL REMAIN 
FAR ENOUGH SOUTH TO HAVE A NEGLIGIBLE EFFECT ON REGIONAL WEATHER. 
MODERATE TO FRESH DRY TRADES WILL DOMINATE AND ANCHOR GENERALLY FAIR 
WEATHER CONDITIONS THROUGH EARLY NEXT WEEK. THERE IS A SLIGHT CHANCE 
AS INDICATED IN THE NOGAPS AND ECMWF MODELS THAT THE SHEAR LINE 
CURRENTLY NORTH OF SAIPAN MAY PENETRATE AS FAR SOUTH AS PALAU AND 
YAP BY THE END OF THE WEEKEND...HOWEVER THE GFS DOES NOT TAKE IT AS 
FAR SOUTH AND SO THIS REMAINS TO BE SEEN.  

WW3 MODEL OUTPUT INDICATES THAT HAZARDOUS SURF WILL PERSIST THROUGH 
SATURDAY FOR YAP AND THROUGH SUNDAY FOR PALAU ON NORTHEASTERN AND 
EASTERN FACING REEFS. A NEW SURGE MAY REACH CHUUK BY EARLY NEXT WEEK.

&&

.GUM WATCHES/WARNINGS/ADVISORIES...
GU...HIGH SURF ADVISORY FROM 6 AM SATURDAY TO 4 AM CHST TUESDAY FOR 
     GUZ001>004.

MARIANAS WATERS...NONE.
&&

$$

STANKO/EDSON

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