085
FXHW60 PHFO 050839 AAA
AFDHFO
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE HONOLULU HI
1035 PM HST WED NOV 4 2009
UPDATE
A RECENT SCATTEROMETER PASS AND RECENT SURFACE OBSERVATIONS SHOW
THAT WINDS HAVE STRENGTHENED AS THE FRONTAL REMNANT HAS PUSHED DOWN
OVER THE ISLANDS. WE HAVE EXPANDED THE SMALL CRAFT ADVISORY TO ALL
COASTAL WATERS AND EXTENDED THE ADVISORY THROUGH THURSDAY EVENING
FOR THE WINDIER AREAS AROUND MAUI AND THE BIG ISLAND.
SYNOPSIS
HIGH PRESSURE TO THE NORTH WILL KEEP TRADE WINDS BLOWING THROUGH
THROUGH THE WEEKEND. THE REMNANT OF A FRONT WILL PRODUCE LOCALLY
BREEZY TRADE WINDS AND SHOWERY WEATHER AS IT MOVES SOUTH OVER THE
ISLANDS TONIGHT AND TOMORROW. THE WEATHER WILL TURN DRIER TOMORROW
NIGHT...BUT ANOTHER SHOWER BAND MAY ARRIVE FRIDAY NIGHT AND BRING
MORE WINDWARD SHOWERS THROUGH THE WEEKEND. WINDS MAY WEAKEN AND
SHIFT TO SOUTHEAST NEXT WEEK AS A FRONT APPROACHES FROM THE
NORTHWEST.
SHORT TERM
TONIGHT 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 TONIGHT BUT REMNANTS OF THE BAND WILL KEEP THE WINDWARD SIDE
OF THE BIG ISLAND A BIT CLOUDY AND SHOWERY TOMORROW. THE WEATHER
WILL TURN DRIER THURSDAY NIGHT 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. THE
BAND IS MOVING SOUTH ABOUT 10 MPH. THAT BAND MAY REACH THE ISLANDS
LATE FRIDAY NIGHT AND BRING SHOWERY WEATHER TO 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
THE SMALL CRAFT ADVISORY...SCA...HAS BEEN EXPANDED TO INCLUDE ALL
OF THE COASTAL WATERS THROUGH THURSDAY MORNING. THE SCA WILL
CONTINUE THROUGH THURSDAY EVENING FOR THE WINDIER AREAS AROUND MAUI
AND THE BIG ISLAND. THE WINDS SHOULD TAPER OFF THURSDAY NIGHT AS THE
PRESSURE GRADIENT WEAKENS. NO BIG SWELLS ARE EXPECTED FOR THE NEXT
SEVERAL DAYS.
HFO WATCHES/WARNINGS/ADVISORIES
SMALL CRAFT ADVISORY UNTIL 6 AM HST THURSDAY FOR ALL WATERS.
SMALL CRAFT ADVISORY 6 AM THURSDAY THROUGH 6 PM THURSDAY FOR THE
PAILOLO AND ALENUIHAHA CHANNELS...MAALAEA BAY AND WATERS SOUTH OF
THE BIG ISLAND.
DONALDSON
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