000
FXPQ60 PGUM 102150
AFDPQ 

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TIYAN GU
750 AM CHST WED FEB 11 2009

.SYNOPSIS...
SHEAR LINE HAS SUNK A BIT FARTHER SOUTH TO AROUND ANATAHAN...WITH
SOME MOISTURE POOLING AHEAD OF IT OVER THE FORECAST ZONES THANKS
TO SE LOW-LEVEL FLOW. RADAR AND SATELLITE SHOW AREAL COVERAGE AND
INTENSITY OF CONVECTION GRADUALLY INCREASING OVER AND AHEAD OF
THE SHEAR LINE. RADAR SHOWS LINE OF SHALLOW CONVECTION FROM
SOUTHERN GUAM ANGLING NORTHWESTWARD TOWARD THE SHEAR LINE. THIS
LINE APPEARS TO BE THE NOSE OF A MODEST SURGE FROM THE SOUTH.
CONVECTION SHOWS ENHANCEMENT WHERE THESE BOUNDARIES INTERSECT.

&&

.DISCUSSION...
NO MAJOR CHANGES MADE TO THE FORECAST GRIDS. WENT WITH A BLEND OF
MODEL SOLUTIONS GIVING MINIMAL WEIGHT TO GFS MASS FIELD
SOLUTIONS. GFS IS SUFFERING FROM TOO MUCH CONVECTIVE FEEDBACK...
ALTHOUGH REMAIN AT LEAST SOMEWHAT SUSPICIOUS A CIRCULATION MIGHT
SPIN UP WHERE THE AFOREMENTIONED BOUNDARIES INTERSECT. AVOIDED
TRYING TO BE TOO PRECISE WITH THE WEATHER GRIDS AS SATELLITE
IMAGERY SHOWS SOME CONVECTION BREAKING OUT TO THE SOUTH OF THE
SHEAR LINE. MODELS ARE STILL SHOWING THE MOST QPF IN THE NORTHERN
ZONES...BUT AT LEAST SOME OF THIS IS DUE TO CONVECTIVE FEEDBACK
SEEN NEAR THESE LOCATIONS. STILL LOOKS LIKE SHEAR LINE CONVECTION
WILL ENTER SAIPAN WATERS TONIGHT AND EXIT GUAM WATERS BY SATURDAY
MORNING. TRADE SURGE WILL USHER IN DRIER AIR SUNDAY THROUGH
TUESDAY.

&&

.MARINE...
TRADE-WIND SURGE IN THE WAKE OF THE SHEAR LINE PASSAGE WILL BRING
SMALL CRAFT ADVISORY CONDITIONS FOR COMBINED SEAS BEGINNING ON
FRIDAY. SUSTAINED WINDS MAY ALSO MEET THE SMALL CRAFT ADVISORY
THRESHOLD. BEST CHANCES FOR THIS APPEAR TO BE FOR TINIAN AND
SAIPAN WATERS. A MINIMAL HIGH SURF ADVISORY EVENT FOR EAST FACING
EXPOSURES IS ALSO POSSIBLE.

&&

.FIRE WEATHER...
KBDI CONTINUES CLIMBING TOWARD 700. PROSPECTS FOR A WETTING RAIN
LOOK GOOD BETWEEN NOW AND SATURDAY WITH AT LEAST SOME INTERACTION
EXPECTED BETWEEN A PASSING SHEAR LINE AND DEEPER MOISTURE
ADVECTING IN FROM THE SOUTH AND SOUTHEAST. SPREAD OF QPF IN THE
MODELS REMAINS CONSIDERABLE...SO WHETHER OR NOT A HEAVY RAINFALL
EVENT MATERIALIZES REMAINS UNCERTAIN.

&&

.EASTERN MICRONESIA...
WEATHER LOOKS FAIRLY QUIET ACROSS THE ISLANDS EXCEPT FOR A TRADE-
WIND DISTURBANCE CURRENTLY LOCATED SOUTH OF KOSRAE. DRIER AIR HAS
PUSHED IN FROM THE NORTHEAST. ALL SIGNIFICANT TRADE-WIND
CONVECTION IS EXPECTED TO PASS SOUTH OF THE FORECAST LOCATIONS
DURING THE NEXT FEW DAYS.

THE MAIN CONCERN TOWARD THE END OF THE WEEK IS THE WHEN LARGE NW
SWELLS ARRIVE. IT MAY BE TOO EARLY TO SPECULATE ON THE
SIGNIFICANCE OF THIS EVENT BUT WILL MONITOR THIS SITUATION. WAVE
WATCH EXTENDS HAZARDOUS SURF FOR EAST-FACING SHORES ON KOSRAE FOR
ANOTHER DAY. THE SURF SHOULD SUBSIDE BELOW ADVISORY HEIGHTS BY
THURSDAY MORNING.

&&

.WESTERN MICRONESIA...
CONVECTION NORTH AND SOUTH OF PALAU HAS INTENSIFIED DURING THE
PAST FEW HOURS. A SURFACE CIRCULATION NORTHWEST OF KOROR WILL
CONTINUE TO DRIFT TOWARDS MINDANAO. HOWEVER...A SURFACE TROUGH
EXTENDING NORTHEASTWARD FROM KOROR AND YAP WILL ACT AS A FOCUS FOR
SCATTERED SHOWERS AND TSTMS ACROSS THE ISLANDS FOR THE NEXT FEW
DAYS. ON CHUUK...A MODEST TRADE-WIND DISTURBANCE ARRIVING FROM THE
EAST-SOUTHEAST WILL USHER IN SCATTERED SHOWERS TONIGHT AND
THURSDAY.

A SHORT-LIVED NNW SWELL ON CHUUK IS CAUSING SURF JUST BELOW THE
HIGH SURF THRESHOLD. SURF ON NORTH FACING EXPOSURES IS EXPECTED
TO SUBSIDE THROUGH FRIDAY TO 7 TO 8 FT. ANOTHER NNW SWELL IS PROGGED
TO ARRIVE BY LATE SUNDAY AND IS WORTH WATCHING FOR THE NEXT FEW
DAYS. OTHERWISE...SIGNIFICANT SWELLS ARE NOT EXPECTED DURING THE
NEXT FEW DAYS.

&&

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

$$

MCELROY/BAQUI