FXHW60 PHFO 201338
AFDHFO
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HONOLULU HI
338 AM HST TUE JAN 20 2009
.SYNOPSIS...
A WEAK FRONT WILL REACH KAUAI EARLY THIS MORNING...OAHU BY
MIDMORNING...THEN CONTINUE EAST THROUGH MAUI COUNTY IN THE
AFTERNOON. THE DISSIPATING FRONT WILL REACH THE BIG ISLAND IN THE
EVENING. CLOUDS AND LIMITED SHOWERS ALONG THE FRONT WILL AFFECT
EACH ISLAND IN TURN...WITH FRESH NORTHERLY WINDS FILLING IN BEHIND
THE FRONT. TRADE WINDS WILL RETURN TO ALL OF THE MAIN ISLANDS BY
WEDNESDAY...AND ARE EXPECTED TO LAST INTO THE WEEKEND. WINDS WILL
BECOME SOUTHEASTERLY AGAIN NEXT SUNDAY AND MONDAY AS A TROUGH
DEVELOPS WEST OF THE MAIN ISLANDS.
&&
.DISCUSSION...
RAINFALL HAS BEEN MINIMAL OVERNIGHT WITH THE ONLY MEASURED
RAINFALL COMING FROM AN ISOLATED SHOWER THAT MOVED OVER THE
SOUTHWEST PORTION OF OAHU. INCREASING WINDS AND CLOUD COVER HAVE
TEMPERED THE LOW TEMPERATURES OVER KAUAI AND OAHU...WHILE CLEAR
SKIES AND DOWNSLOPE WINDS HAVE KEPT TEMPS CHILLY THIS MORNING OVER
MAUI COUNTY AND THE BIG ISLAND.
AS OF 3 AM...THE LEADING EDGE OF A 200 MILE WIDE CLOUD BAND ASSOCIATED
WITH A WEAK COLD FRONT HAD REACHED THE EAST COAST OF KAUAI AND
CONTINUES TO MOVE 20 MPH TOWARD THE SOUTHEAST. RADAR IS SHOWING A
BAND OF WEAK SHOWERS MOVING TOWARD KAUAI FROM THE WEST. THESE
SHOWERS WILL REACH THE GARDEN ISLE BY 4 AM BRINGING LIMITED
RAINFALL AMOUNTS. WINDS WILL STEADILY INCREASE OVER KAUAI AND OAHU
THIS MORNING WITH THE CLOUD BAND AND LIGHT SHOWERS REACHING OAHU
BY MIDMORNING. THE FRONT WILL WEAKEN FURTHER AS IT PASSES THROUGH
THE ISLANDS...REACHING MAUI COUNTY IN THE AFTERNOON...AND
DISSIPATING NEAR THE BIG ISLAND TUESDAY NIGHT.
MODELS ARE DEPICTING VERY LOW RAINFALL TOTALS AS THIS SYSTEM
LACKS THE UPPER LEVEL SUPPORT NECESSARY FOR SUBSTANTIAL RAINS.
THE 850 MB WINDS ALONG THE FRONT ARE MODELED BELOW 25 MPH
THROUGHOUT...SO STRONG GUSTS ARE NOT EXPECTED.
FRESH...POST FRONTAL NORTHERLY WINDS WILL MOVE IN BEHIND THE FRONT
TODAY...REACHING THE BIG ISLAND TONIGHT. THE NORTHERLY WINDS WILL
SHIFT TO THE NORMAL NORTHEAST TRADE WIND DIRECTION BY WEDNESDAY. A RIDGE
FILLING IN NORTH OF THE STATE IS EXPECTED TO REMAIN INTACT THROUGH
THE WEEK...CONTINUING THE MODERATE TO FRESH TRADE WINDS. MODELS
ARE DEPICTING A TROUGH FORMING WEST OF THE ISLANDS OVER THE
WEEKEND...WHICH WILL VEER OUR WINDS OUT OF THE SOUTHEAST. THE
LOCATION OF THIS TROUGH IS STILL MUCH DEBATED BY THE GLOBAL
MODELS...SO THE FORECAST WILL REMAIN ON THE CONSERVATIVE SIDE
UNTIL THE MODELS SORT OUT THEIR DIFFERENCES.
&&
.MARINE...
FORERUNNERS OF THE NEXT LARGE NORTHWEST SWELL WILL ARRIVE THIS
AFTERNOON WITH SURF INCREASING TO ADVISORY LEVELS THIS AFTERNOON. NORTH
WINDS WILL PRODUCE ROUGH OCEAN CONDITIONS TONIGHT AND WEDNESDAY
MORNING...WITH SURF HEIGHTS EXPECTED TO REMAIN JUST BELOW WARNING
LEVELS ALONG NORTH AND WEST FACING SHORES. THIS SWELL WILL SLOWLY
DECLINE THURSDAY AND FRIDAY.
&&
.HFO WATCHES/WARNINGS/ADVISORIES...
HIGH SURF ADVISORY FROM 6 PM THIS EVENING TO 6 PM HST THURSDAY 
FOR NIIHAU-KAUAI WINDWARD-KAUAI LEEWARD-WAIANAE COAST-OAHU NORTH 
SHORE-OAHU KOOLAU-MOLOKAI-MAUI WINDWARD WEST-MAUI CENTRAL VALLEY-
WINDWARD HALEAKALA.
WIND ADVISORY UNTIL 6 PM HST THIS AFTERNOON FOR HALEAKALA SUMMIT-
BIG ISLAND SUMMITS.
&&
$$
MORRISON