717
FXHW60 PHFO 051339
AFDHFO
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HONOLULU HI
400 AM HST THU NOV 5 2009
SYNOPSIS
HIGH PRESSURE TO THE NORTH WILL KEEP TRADE WINDS BLOWING THROUGH
THROUGH THE WEEKEND. THE REMNANT OF A FRONT WILL PRODUCE SHOWERY
WEATHER OVER MAUI COUNTY AND THE BIG ISLAND TODAY. THE WEATHER WILL
TURN DRIER TONIGHT...BUT ANOTHER SHOWER BAND MAY ARRIVE FRIDAY NIGHT
AND BRING MORE WINDWARD SHOWERS THROUGH THE WEEKEND. WINDS MAY
WEAKEN AND SHIFT TO SOUTH NEXT WEEK AS A FRONT APPROACHES FROM THE
NORTHWEST. HEAVY SHOWERS ARE POSSIBLE FOR THE MIDDLE OF NEXT WEEK.
SHORT TERM
TODAY THROUGH SUNDAY.
RADAR AND SATELLITE LOOPS SHOW AN EAST TO WEST CLOUD BAND ACROSS
MAUI COUNTY AND THE BIG ISLAND. THE BAND IS PRODUCING SHOWERS OVER
WINDWARD AREAS FROM MOLOKAI TO THE BIG ISLAND WITH SOME OF THE
SHOWERS SPREADING LEEWARD ON MOLOKAI. THE BAND WILL CLEAR MAUI
COUNTY TODAY...BUT REMNANTS OF THE BAND WILL KEEP THE WINDWARD SIDE
OF THE BIG ISLAND A BIT CLOUDY AND SHOWERY. THE WEATHER WILL TURN
DRIER TONIGHT AS THE OLD FRONTAL BAND DISSIPATES.
SATELLITE IMAGERY SHOWS ANOTHER EAST TO WEST BAND OF SHOWERY LOW
CLOUDS ABOUT 250 MILES NORTHEAST OF THE MAIN HAWAIIAN ISLANDS. THAT
BAND MAY REACH THE ISLANDS LATE FRIDAY NIGHT AND INCREASE SHOWERS
OVER WINDWARD AREAS SATURDAY AND SUNDAY.
RIDGING ALOFT IS BUILDING OVER THE ISLANDS SO THE ATMOSPHERE WILL
REMAIN RATHER STABLE THROUGH THE WEEKEND. IT SHOULD BE STABLE ENOUGH
SO THAT THE SHOWERS COMING IN WITH THE TWO CLOUD BANDS MENTIONED
ABOVE WILL NOT BE TOO HEAVY.
LONG TERM
MONDAY THROUGH VETERANS DAY.
THE FORECAST FOR NEXT WEEK REMAINS HIGHLY UNCERTAIN. THE GLOBAL
MODELS ARE NOT IN GOOD AGREEMENT AND THERE ARE BIG RUN TO RUN
DIFFERENCES IN MANY OF THE MODELS. IT DOES LOOK LIKE A TROUGH ALOFT
AND AN ASSOCIATED FRONT WILL BE DIGGING SOUTHEAST TOWARD THE ISLANDS
EARLY NEXT WEEK. THAT SHOULD CAUSE THE WINDS OVER THE ISLANDS TO
WEAKEN AND SHIFT TO THE SOUTHEAST EARLY NEXT WEEK. HOWEVER...THE
MODELS DIFFER GREATLY ON HOW FAST THE TROUGH WILL MOVE AND HOW FAR
SOUTH IT WILL DIG. IN ANY CASE...IT LOOKS AS IF THE TRADE-WIND FLOW
OVER THE ISLANDS WILL BE DISRUPTED MUCH OF NEXT WEEK. IF THE TROUGH
DIGS SOUTHEAST FAR ENOUGH...HEAVY RAINFALL COULD DEVELOP. UNTIL THE
MODELS BECOME MORE CONSISTENT WE WILL NOT BE ABLE TO BE VERY
CONFIDENT ABOUT THE CHANCE OF HEAVY RAIN.
MARINE
WINDS HAVE TAPERED OFF A BIT OVERNIGHT BUT A SMALL CRAFT ADVISORY
REMAINS UP FOR MANY AREAS. THE PAILOLO AND ALENUIHAHA CHANNELS...
MAALAEA BAY AND WATERS SOUTH OF THE BIG ISLAND WILL HAVE 25 KT WINDS
WINDS WILL BE LESS THAN 24 KT ELSEWHERE BUT THE KAUAI AND KAIWI
CHANNELS AND THE KAUAI NORTHWEST WATERS WILL HAVE SEAS OF 10 FT OR
GREATER. THE WINDS SHOULD TAPER OFF TONIGHT AS THE PRESSURE GRADIENT
WEAKENS. THE CURRENT NORTHWEST SWELL WILL SLOWLY DIMINISH AND NO
OTHER LARGE SWELLS ARE EXPECTED FOR THE NEXT SEVERAL DAY.
HFO WATCHES/WARNINGS/ADVISORIES
SMALL CRAFT ADVISORY THROUGH 6 PM THURSDAY FOR ALL CHANNELS...
KAUAI NORTHWEST WATERS...MAALAEA BAY AND WATERS SOUTH OF THE BIG
ISLAND.
DONALDSON
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