FXHW60 PHFO 111339
AFDHFO
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HONOLULU HI
400 AM HST FRI DEC 11 2009
.SYNOPSIS...
TRADE WINDS HAVE INCREASED SLIGHTLY BUT WILL BECOME LIGHT AND
VARIABLE THIS WEEKEND WHEN THE SURFACE HIGH PRESSURE RIDGE MOVES
BACK OVER THE ISLANDS. WEATHER SHOULD CONTINUE TO BE MOSTLY DRY AND
SUNNY,
&&
.DISCUSSION...
STABLE CLOUDS WITH VERY WEAK AND ONLY ISOLATED SHOWERS ARE MOVING IN
AN EAST SOUTHEASTERLY TRADE WIND FLOW. THE AIR MASS CONTINUES TO BE
RELATIVELY DRY AND THE TEMPERATURE INVERSION REMAINS LOW ESPECIALLY
OVER KAUAI..NEAR 3300 FEET...AND PRECIPITABLE WATER IS STILL NEAR 1
INCH.
A FRONT ABOUT 300 MILES NORTH WILL SHIFT FARTHER NORTH AS IT IS
DRAWN INTO THE CIRCULATION OF A DEVELOPING LOW THAT IS MOVING INTO
THE NORTHEAST PACIFIC. TRADE WINDS WILL CEASE THIS WEEKEND. LIGHT
SOUTHEAST WINDS SATURDAY WILL BECOME VARIABLE ON SUNDAY AND ALSO
MONDAY. WINDS WILL EXHIBIT THE TYPICAL ALTERNATION OF DAYTIME SEA
BREEZES AND NIGHTTIME LAND BREEZES. MOSTLY SUNNY WEATHER IS EXPECTED
EXCEPT FOR SOME AFTERNOON CLOUD FORMATION FROM SEA BREEZE
CONVERGENCE AND AFTERNOON HEATING OF THE LAND. UNDER SUCH STABLE
CONDITIONS ANY AFTERNOON SHOWER ACTIVITY WOULD BE MINIMAL.
THERE ARE STILL SOME DIFFERENCES BETWEEN COMPUTER MODELS REGARDING A
COLD FRONT DURING THE MIDDLE NEXT WEEK. LATEST EUROPEAN MODEL A
LITTLE CLOSER TO GFS SOLUTION BUT GFS DEPICTS STRONGER UPPER TROUGH
CROSSING THE ISLANDS THURSDAY. CURRENT FORECAST PACKAGE ATTEMPTS TO
COMPROMISE BETWEEN THESE MODELS AND REFLECTS A COLD FRONT PASSING
THROUGH THE ISLANDS WEDNESDAY.
PRESENTLY THERE IS A DEVELOPING LOW THAT HAS JUST PASSED THE
DATELINE. SOME MOISTURE EXPECTED FROM THE ASSOCIATED FRONT WHEN IT
APPEARS TO WEAKEN OR STALL JUST AS IT REACHES KAUAI MONDAY. THE
EUROPEAN MODEL SUGGESTS SLIGHTLY MORE MOISTURE AROUND KAUAI HOWEVER.
THE MORE SIGNIFICANT FRONT IS THE SECOND ONE. BOTH THE CURRENT
EUROPEAN MODEL AND THE GFS BOTH BRING IT UP TO THE ISLANDS
WEDNESDAY. THE EUROPEAN MODEL PUSHES IT ALL THE WAY PAST THE BIG
ISLAND BY THURSDAY EVENING. THE GFS DEVELOPS A LOW WEDNESDAY JUST
NORTHWEST OF THE ISLANDS...MOVES THE FRONT A LITTLE SLOWER AND HAS
STRONGER SOUTHWEST TO WEST WINDS ACCOMPANYING ITS PASSAGE...AND
POTENTIALLY A WETTER FRONTAL EVENT.
&&
.HFO WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
HOAG
