565
FXHW60 PHFO 060625
AFDHFO
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HONOLULU HI
830 PM HST SAT JUL 5 2008
SYNOPSIS
TRADE WIND SPEEDS WILL DECREASE SLIGHTLY SUNDAY AND
MONDAY...BEFORE INCREASING AGAIN TO MODERATE LEVELS NEXT TUESDAY AND
WEDNESDAY. THE LIGHTER TRADE WINDS WILL CONTINUE TO BRING CLOUDS AND
SHOWERS MAINLY TO WINDWARD AREAS OF THE ALOHA STATE...WITH A SLIGHT
CHANCE OF LIGHT SHOWERS OCCURRING OVER LEEWARD SECTIONS.
DISCUSSION
THE PREVIOUS FORECAST PACKAGE APPEARS TO BE ON TRACK.
THEREFORE...EXPECT NO MAJOR UPDATES THIS EVENING.
PREV DISCUSSION ISSUED AT 423 PM HST
LITTLE RAIN HAS FALLEN OVER
THE STATE SINCE THIS MORNING AND THE SMALL AMOUNT THAT HAS FALLEN
HAS BEEN RELEGATED TO WINDWARD AND MOUNTAIN REGIONS OF KAUAI AND
ALONG THE KOOLAU MTS OF OAHU. MOST SHOWERS CLOSE TO THE ISLANDS ARE
REMAINING NORTH OF THE STATE AND ARE MOVING TOWARD THE WEST WITH A
SLIGHT NORTHERLY COMPONENT... STAYING AWAY FROM THE STATE. HAVE
DECREASED THE POP FORECAST THIS EVENING OVER WINDWARD AREAS EXCEPT
KAUAI WITH MOSTLY CLEAR SKIES UPSTREAM OF THE ISLANDS. SOME LIGHT
SHOWERS MAY REACH THE SOUTHEAST COAST OF OAHU THIS EVENING DUE TO
CONVERGENT SHOWERS FORMING OVER THE LEE WATERS OF MOLOKAI. LATE
TONIGHT THE WINDWARD POP FORECAST INCREASES BACK TO SCATTERED WITH
CLOUD TOP COOLING INCREASING THE CHANCE OF SHOWERS.
AN UPPER LEVEL LOW CENTERED 250 MILES EAST OF HILO IS MOVING 15 MPH
TOWARD THE WEST. THE LOW HAS BEGUN TO SHOW ITSELF VISIBLY WITH HIGH
CIRRUS FORMING NORTH OF MAUI AND OAHU. THE AFTERNOON HILO SOUNDING
SHOWS THE LOW HAS COOLED THE ATMOSPHERE ABOVE 10 THOUSAND FEET BY
ABOUT 2 DEGREES C OVER THE PAST 24 HOURS. THIS COOLING HAS
DESTABILIZED THE ATMOSPHERE SLIGHTLY BUT IT DOES NOT SEEM TO BE
STRONG ENOUGH TO ENHANCE THE ISLANDS RAINFALL SIGNIFICANTLY.
HOWEVER...THE LOW WILL DECREASE THE PRESSURE GRADIENT OVER THE STATE
SUNDAY AND MONDAY...SLOWING THE TRADE WINDS TO THE LIGHT CATEGORY.
GENERALLY...LIGHT TO MODERATE TRADES WILL CONTINUE INTO NEXT WEEK. A
HIGH PRESSURE IS CENTERED 700 MILES NORTH OF KAUAI WITH ITS
ASSOCIATED RIDGE EXTENDING WEST TO THE DATELINE AND EAST INTO THE
EAST PACIFIC. THE RIDGE IS FORECASTED TO REMAIN NORTH OF THE STATE
ALONG 30 N...WHILE THE HIGH PRESSURE CENTER GRADUALLY MOVES FAR
NORTHEAST...ENDING UP 1600 MILES AWAY FROM THE STATE BY WEDNESDAY.
THIS SYNOPTIC SCALE PATTERN WILL KEEP TRADE WINDS LIGHT TO MODERATE
THROUGH THE FORECAST PERIOD. SYNOPTIC WINDS WILL BE LIGHTEST SUNDAY
AND MONDAY ALLOWING SEA BREEZES TO INCREASE ALONG LEE COASTS OF THE
ISLANDS...AND FORM ALONG SOME SOUTH FACING COASTS WHICH NORMALLY
EXPERIENCE TRADES. BY TUESDAY...AND INTO THE WEEK...TRADES LOOK TO
BE STRONG ENOUGH TO RELEGATE SEA BREEZES BACK TO THE WEST AND
SOUTHWEST FACING LEEWARD COASTS.
FOR PRECIPITATION...SHOWERS WILL CONTINUE TO FALL MAINLY OVER
WINDWARD LOCATIONS WITH ISOLATED SHOWERS OVER LEEWARD AREAS AT
NIGHT. SUNDAY AND MONDAY AFTERNOON MAY BRING INCREASED CLOUDS AND
SHOWERS OVER INTERIOR AND ELEVATED AREAS DUE TO SEA BREEZE
CIRCULATIONS. KAUAI WILL CONTINUE TO RECEIVE THE MAJORITY OF SHOWERS
OVER THE STATE WITH THE GFS MODEL CONTINUING TO SHOW HIGHER MOISTURE
LEVELS MOVING OVER THE ISLAND INTO MONDAY NIGHT. IN THE
LONGTERM...THE GFS SHOWS THE REMNANT MOISTURE OF TROPICAL STORM
BORIS REACHING THE BIG ISLAND WEDNESDAY...INCREASING WINDWARD
SHOWERS.
MARINE
EVEN THOUGH MODERATE TRADE WIND SPEEDS ARE EXPECTED TO
RETURN LATER NEXT WEEK...THE WIND SPEEDS ARE EXPECTED TO REMAIN
BELOW THE SMALL CRAFT ADVISORY THRESHOLD IN ALL MARINE ZONES. SMALL
BACKGROUND SOUTH SWELLS WILL KEEP SURF HEIGHTS ALONG THE SOUTH
FACING SHORES OF ALL ISLANDS BELOW THE HIGH SURF ADVISORY THRESHOLD
DURING THE NEXT SEVERAL DAYS. ELSEWHERE...SMALL NORTH AND NORTHWEST
SWELLS ARE EXPECTED TO CONTINUE THROUGH MONDAY.
HFO WATCHES/WARNINGS/ADVISORIES
NONE.
DISCUSSION...HOUSTON
PREV DISCUSSION...MORRISON
MARINE...HOUSTON
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