Area Forecast Discussion
Issued by NWS Honolulu, HI

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000
FXHW60 PHFO 100630
AFDHFO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HONOLULU HI
830 PM HST TUE FEB 9 2016

.SYNOPSIS...
COOL...DRY WEATHER WILL CONTINUE THROUGH WEDNESDAY WITH LIGHT
WINDS DUE TO A WEAK SURFACE RIDGE IN THE VICINITY OF THE ISLANDS.
GENTLE TRADE WINDS WILL RETURN DURING THE SECOND HALF OF THIS WEEK
AS A SURFACE HIGH PASSES NORTH OF THE ALOHA STATE. A FRONT
APPROACHING THE STATE FROM THE NORTHWEST WILL RESULT IN WINDS
TURNING MORE SOUTHEASTERLY OVER THE SMALLER ISLANDS THIS WEEKEND.

&&

.DISCUSSION...
A SURFACE FRONT LOCATED ABOUT 240 MILES NORTH OF LIHUE HAS PUSHED
THE SURFACE RIDGE DOWN OVER THE MAIN HAWAIIAN ISLANDS. THE CLOSE
PROXIMITY OF THIS EAST TO WEST ORIENTED RIDGE TO THE STATE HAS
CAUSED THE BACKGROUND WINDS TO BE WEAK ACROSS THE ISLAND CHAIN.
THESE LIGHT SYNOPTIC WINDS ARE ALLOWING LOCAL NIGHTTIME LAND
BREEZES TO FORM OVER THE INTERIOR SECTIONS OF MOST ISLANDS THIS
EVENING. IN ADDITION TO THE LIGHT WINDS...THE ATMOSPHERE REMAINS
RATHER DRY AND STABLE. THERE ARE FEW...IF ANY...LOW CLOUDS AND
SHOWERS OVER THE SMALLER ISLANDS. LOW CLOUDS OVER THE LOWER
ELEVATIONS OF THE BIG ISLAND... WHICH HAD DEVELOPED EARLIER
TODAY...ARE BEGINNING TO DISPERSE DUE TO THE DOWNSLOPING WINDS
THAT ARE FORMING AFTER DUSK THIS EVENING. NOTE THAT THE CLEAR
SKIES OVER MOST OF THE ISLANDS WILL RESULT IN COOL TEMPERATURES
AGAIN THROUGH EARLY WEDNESDAY MORNING.

THE FORECAST MODELS CONTINUE TO INDICATE THE SURFACE RIDGE WILL
REMAIN IN THE VICINITY OF THE ISLANDS THROUGH WEDNESDAY. THIS WILL
MAINTAIN LIGHT WINDS AND STABLE ATMOSPHERIC CONDITIONS THROUGH
WEDNESDAY AFTERNOON. LOCAL AFTERNOON SEA BREEZE CIRCULATIONS MAY
ALLOW SOME LOW CLOUDS TO DEVELOP OVER INTERIOR SECTIONS OF SOME
ISLANDS...MAINLY THE LOWER ELEVATIONS OF THE BIG ISLAND...BUT FEW
SHOWERS ARE ANTICIPATED.

A SURFACE HIGH MOVING BY NORTH OF THE ISLANDS FROM WEDNESDAY
NIGHT THROUGH THURSDAY WILL CAUSE A SLIGHT TIGHTENING OF THE
PRESSURE GRADIENT OVER THE STATE. THIS IS EXPECTED TO ALLOW
GENTLE TRADES TO DEVELOP ACROSS MOST AREAS. THIS HIGH WILL MOVE
TO THE EAST AND THEN NORTHEAST DURING THE END OF THE WEEK...SO
ITS INFLUENCE ON LOCAL WEATHER WILL GRADUALLY DIMINISH. THE
ROUNDED WESTERN END OF A SURFACE RIDGE EXTENDING WEST-SOUTHWEST
OF THIS HIGH IS FORECAST TO REMAIN TO THE NORTH OF THE AREA. THE
CLOSE PROXIMITY OF THIS FEATURE TO THE WESTERN ISLANDS WILL ALLOW
THE LOW LEVEL FLOW TO SHIFT OUT OF THE EAST-SOUTHEAST TO SOUTHEAST
OVER MOST OF THE SMALLER ISLANDS BY THIS WEEKEND.

A FRONT APPROACHING THE ISLANDS FROM THE NORTHWEST SUNDAY WILL
ERODE THE WESTERN END OF THIS RIDGE. THE ARRIVAL OF THIS FRONT
WILL LIKELY BRING AN INCREASE IN SHOWER IN THE VICINITY OF KAUAI
BY SUNDAY NIGHT. A NEW SURFACE HIGH BUILDING BEHIND THIS FRONT
WILL MOVE EASTWARD...AND WILL EVENTUALLY CAUSE THE FRONT TO MOVE
DOWN THE ISLAND CHAIN. THE FRONT WILL BRING AN INCREASE IN CLOUDS
AND SHOWERS TO THE ISLANDS...ALONG WITH STRONG AND GUSTY NORTH TO
NORTHEAST WINDS AFTER IT PASSES. THE LATEST MODEL OUTPUT DOES NOT
APPEAR TO SHOW HEAVY RAINFALL ASSOCIATED WITH THE FRONTAL
PASSAGE.

&&

.AVIATION...
VFR CONDITIONS ARE EXPECTED TO PREVAIL THROUGH WEDNESDAY MORNING.
NO AIRMETS ARE ANTICIPATED.

&&

.MARINE...
THE LONG PERIOD ENERGY FROM THE LATEST VERY LARGE WINTERTIME
NORTH-NORTHWEST SWELL HAS ARRIVED AT BUOYS 51001 AND 51101 LOCATED
NORTHWEST OF KAUAI. THERE ARE ALSO LONG PERIOD FORERUNNERS SHOWING
UP AT THE HANALEI AND WAIMEA BAY BUOYS. NOTE THAT THE ARRIVAL OF
THIS INITIAL ENERGY WAS DELAYED SLIGHTLY COMPARED WITH THE
GUIDANCE FROM THE WAVE WATCH III...WHICH HAS BEEN THE CASE FOR
MOST OF THE RECENT WINTERTIME SWELL EVENTS. HOWEVER...WE STILL
EXPECT THE SWELL TO BUILD SIGNIFICANTLY OVERNIGHT.

SURF PRODUCED BY THIS SWELL WILL LIKELY INCREASE TO THE HIGH SURF
WARNING CRITERIA ALONG MOST NORTH AND WEST FACING SHORES OF THE
SMALLER HAWAIIAN ISLANDS BY DAYBREAK WEDNESDAY. IN ADDITION...THE
ENERGY FROM THIS SWELL WILL ALSO LIKELY REACH BOTH THE WEST AND
NORTH FACING SHORES OF THE BIG ISLAND BY MID-DAY WEDNESDAY. AS A
RESULT...A HIGH SURF WARNING HAS BEEN ISSUED STARTING AT NOON HST
WEDNESDAY FOR WEST FACING SHORES OF THE BIG ISLAND...WHILE A HIGH
SURF ADVISORY WILL BE IN EFFECT STARTING AT NOON HST FOR NORTH
FACING SHORES OF THE BIG ISLAND.

NOTE THAT THIS NORTH-NORTHWEST SWELL WILL CONTINUE FOR AN
EXTENDED PERIOD OF TIME...WHICH MEANS THAT SURF WILL REMAIN
ELEVATED OVER MULTIPLE TIDE CYCLES. SEE THE COLLABORATIVE
NEARSHORE SWELL AND WIND FORECAST FOR OAHU FOR MORE DETAILED
INFORMATION ABOUT THIS SWELL. LOCALIZED COASTAL FLOODING IS
POSSIBLE IN THE WARNING AREA DUE TO SIGNIFICANT WAVE SET UP AND
RUN UP ALONG THE BEACHES EXPOSED TO THIS SWELL...ESPECIALLY
DURING EACH HIGH TIDE FROM WEDNESDAY INTO THURSDAY.

THIS SWELL WILL GRADUALLY SUBSIDE FROM THURSDAY NIGHT THROUGH
EARLY FRIDAY...AND SHOULD DROP BELOW THE HIGH SURF ADVISORY
CRITERIA BY LATE FRIDAY. ANOTHER WEST-NORTHWEST SWELL IS EXPECTED
TO ARRIVE SUNDAY...AND PRODUCE SURF REACHING THE HIGH SURF
ADVISORY CRITERIA ALONG MOST NORTH AND WEST FACING SHORES OF THE
SMALLER ISLANDS SUNDAY AND MONDAY. THE WESTERLY COMPONENT OF THIS
SWELL MAY ALSO PRODUCE ADVISORY LEVEL SURF ALONG THE WEST FACING
SHORES OF THE BIG ISLAND FROM LATE SUNDAY INTO MONDAY.

A SMALL CRAFT ADVISORY REMAINS IN EFFECT THROUGH THURSDAY FOR
MOST HAWAIIAN WATERS DUE TO THE ELEVATED SEAS ASSOCIATED WITH THE
NEW NORTH-NORTHWEST SWELL.

&&

.HFO WATCHES/WARNINGS/ADVISORIES...
HIGH SURF WARNING UNTIL 6 PM HST THURSDAY FOR NORTH AND WEST
FACING SHORES OF NIIHAU...KAUAI...OAHU AND MOLOKAI...AND FOR
NORTH FACING SHORES OF MAUI.

HIGH SURF WARNING FROM NOON WEDNESDAY TO 6 PM HST THURSDAY FOR
WEST FACING SHORES OF THE BIG ISLAND.

HIGH SURF ADVISORY FROM NOON WEDNESDAY TO 6 PM HST THURSDAY FOR
NORTH FACING SHORES OF THE BIG ISLAND.

SMALL CRAFT ADVISORY UNTIL 6 PM HST THURSDAY FOR KAUAI NORTHWEST
WATERS-KAUAI WINDWARD WATERS-KAUAI LEEWARD WATERS-KAUAI CHANNEL-
OAHU WINDWARD WATERS-OAHU LEEWARD WATERS-KAIWI CHANNEL-MAUI
COUNTY WINDWARD WATERS-ALENUIHAHA CHANNEL-BIG ISLAND WINDWARD
WATERS.

&&

$$

HOUSTON


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