High Surf in Hawaii, April 29 to 30, 2015

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HONOLULU HI
400 AM HST WED APR 29 2015

.SYNOPSIS...
A STRONG SURFACE HIGH PRESSURE FAR NORTH OF THE ISLANDS WILL
CONTINUE TO BRING STRONG AND GUSTY TRADE WINDS TO THE STATE TODAY.
THE TRADES WILL EASE SLIGHTLY THURSDAY TO MODERATE LEVELS AND
DECREASE A LITTLE MORE INTO THE WEEKEND. SHOWERS WILL FAVOR
WINDWARD AND MOUNTAIN AREAS WITH SOME SHOWERS REACHING THE LEEWARD
LOCATIONS ON THE SMALLER ISLANDS. THE LEEWARD BIG ISLAND WILL SEE A
FEW SHOWERS EACH AFTERNOON.

&&

.DISCUSSION...
RATHER BRISK TRADE WINDS CONTINUE ACROSS THE ISLANDS EARLY THIS
MORNING AS A STRONG SURFACE HIGH PRESSURE LOCATES FAR NORTH OF THE
AREA. THIS HIGH IS EXPECTED TO BE THE STRONGEST TODAY. THEREFORE
EXPECT THE FIRM TRADE WINDS TO PERSIST ACROSS THE ISLANDS TODAY.
WINDS WILL REMAIN STRONG ENOUGH OVER SOME WIND PRONE AREAS ON THE
WINDWARD BIG ISLAND AS WELL AS LANAI...AND WEST AND CENTRAL MAUI
SUCH THAT A WIND ADVISORY CONTINUES FOR THOSE AREAS THROUGH THIS
EVENING. BULK OF THE REMNANT MOISTURE FROM THE DISSIPATING FRONT IS
NOW STAYING NORTH OF THE ISLANDS...AS REVEALED BY THE LATEST
SATELLITE IMAGERY. BUT THEN THERE ARE MORE LOW CLOUDS EAST OF THE
ISLANDS AT THIS TIME. THESE CLOUDS WILL REACH THE ISLANDS THROUGH
THE REST OF THE MORNING...BRINGING MORE PASSING SHOWERS. MUCH OF THE
LOW CLOUDS WITH EMBEDDED SHOWERS WILL AFFECT MAINLY WINDWARD
AREAS...THOUGH SOME OF THESE LOW CLOUDS AND SHOWERS WILL REACH THE
LEE AREAS OF THE SMALLER ISLANDS UNDER THE BRISK WINDS. EARLY
MORNING LIHUE AND HILO REVEALED A RATHER HIGH INVERSION...AT ABOUT
10K FEET...WHILE LOW LEVEL MOISTURE EXTENDS TO ONLY ABOUT 6K FEET.
AIRMASS IS STILL A LITTLE UNSTABLE OVER THE WESTERN END OF THE STATE
WHILE IT IS MORE STABLE ON THE EASTERN END. REGARDLESS...THE PASSING
SHOWERS WILL BRING MEASURABLE PRECIPITATION TO THE AREAS...THOUGH
THESE SHOWERS WILL MOVE FAST ENOUGH HAMPERING THE ACCUMULATED
AMOUNTS.

LATEST FORECAST SOLUTIONS ARE IN GOOD AGREEMENT...INDICATING THE
AFOREMENTIONED SURFACE HIGH WILL SLOWLY DRIFT NORTH THEN WEAKEN
BEGINNING TONIGHT. THEREFORE...TRADE WINDS WILL DECREASE SLIGHTLY
THURSDAY...THEN EASE FURTHER TO MODERATE/FRESH LEVELS BY FRIDAY.
FORECAST SOLUTIONS SHOW THE SURFACE HIGH WILL PERSIST FAR NORTHEAST
OF THE STATE THROUGH THE WEEKEND INTO EARLY NEXT WEEK. HENCE...MORE
TYPICAL TRADE WIND WEATHER IS EXPECTED BY THE WEEKEND...WITH PASSING
LOW CLOUDS AND SHOWERS AFFECTING MAINLY WINDWARD AREAS.

&&

.AVIATION...
AIRMET TANGO FOR LOW-LEVEL TURB S THRU W OF THE TERRAIN WILL BE
POSTED AT LEAST THROUGH TODAY DUE TO THE STRONG WINDS.

VFR CONDITIONS WILL PREVAIL AT MOST OF THE TERMINALS...THOUGH
PASSING LOW CLOUDS AND SHOWERS WILL AFFECT THE AREAS AT
TIMES...BRINGING BRIEF MVFR CONDITIONS...MAINLY TO THE WINDWARD
AREAS.

&&

.MARINE...
GALE WARNING FOR ALENUIHAHA CHANNELS CONTINUES TODAY...AS WELL AS A
SMALL CRAFT ADVISORY /SCA/ FOR THE REST OF THE COASTAL WATERS DUE TO
THE STRONG WINDS. WINDS MAY EASE JUST ENOUGH THIS EVENING FOR THE
WARNING TO BE CANCELED...THOUGH WINDS WILL REMAIN AT LEAST AT SCA
LEVEL THROUGH THURSDAY FOR ALL WATERS. SOME ZONES MAY DROP OUT OF
THE SCA BY THURSDAY EVENING AS THE WINDS RELAX FURTHER.

ELEVATED SHORT-PERIOD TRADE SWELL WILL CONTINUE TO AFFECT THE
EXPOSED EAST FACING SHORES FOR ALL ISLANDS. THUS A HIGH SURF
ADVISORY REMAINS IN EFFECT FOR THOSE SHORES. EXPECT THIS ADVISORY
TO PERSIST UNTIL THE WINDS DECREASE IN THE COMING DAYS.

&&

.HFO WATCHES/WARNINGS/ADVISORIES...
GALE WARNING UNTIL 6 PM HST THIS EVENING FOR ALENUIHAHA CHANNEL.

WIND ADVISORY UNTIL 6 PM HST THIS EVENING FOR LANAI
MAUKA-KAHOOLAWE-MAUI LEEWARD WEST-MAUI CENTRAL VALLEY-BIG
ISLAND NORTH AND EAST-KOHALA-BIG ISLAND INTERIOR.

HIGH SURF ADVISORY UNTIL 6 AM HST THURSDAY FOR KAUAI WINDWARD-
OAHU KOOLAU-OLOMANA-MOLOKAI-MAUI WINDWARD WEST-WINDWARD
HALEAKALA.

SMALL CRAFT ADVISORY UNTIL 6 AM 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-MAUI COUNTY LEEWARD WATERS-MAALAEA BAY-
PAILOLO CHANNEL-BIG ISLAND WINDWARD WATERS-BIG ISLAND LEEWARD
WATERS-BIG ISLAND SOUTHEAST WATERS.

&&

HUI