High Surf in Hawaii, August 1 to 3, 2009

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HONOLULU HI
400 AM HST SAT AUG 1 2009

.SYNOPSIS...
HIGH PRESSURE LOCATED FAR NORTHEAST OF THE ALOHA STATE WILL MAINTAIN
THE TRADE WINDS ACROSS THE AREA THROUGH EARLY NEXT WEEK. THE TRADE
WIND SPEEDS ARE EXPECTED TO INCREASE SLIGHTLY DURING THE NEXT COUPLE
OF DAYS AS TROPICAL CYCLONE LANA PASSES FAR SOUTH OF THE ISLANDS.
CLOUDS AND SHOWERS CARRIED BY THE TRADES WILL CONTINUE MAINLY ACROSS
WINDWARD AND MAUKA SECTIONS OF THE ISLAND CHAIN.

&&

.DISCUSSION...
A 1027 MB SURFACE HIGH LOCATED NEAR 39N 145W...OR MORE THAN 1300
MILES NORTHEAST OF HONOLULU...REMAINS NEARLY STATIONARY THIS
MORNING. THE PRESSURE GRADIENT SOUTH OF THIS FEATURE CONTINUES TO
MAINTAIN TRADE WINDS ACROSS THE STATE. IN ADDITION TO THE HIGH AT
THE SURFACE...A WEAKENING UPPER TROPOSPHERIC TROUGH IS LOCATED JUST
WEST OF KAUAI. THE CLOSE PROXIMITY OF THIS FEATURE ALOFT TO THE
ISLANDS WILL LIKELY KEEP THE ATMOSPHERE OVER PARTS OF THE STATE
SLIGHTLY UNSTABLE...AT LEAST THROUGH THIS AFTERNOON. THEREFORE...
EXPECT PASSING SHOWERS TO AFFECT THE ISLANDS AT TIMES THROUGH THIS
AFTERNOON...ESPECIALLY OVER WINDWARD AND MAUKA AREAS.

SURFACE HIGH PRESSURE WILL PREVAIL FAR NORTHEAST OF THE ALOHA STATE
THROUGH EARLY NEXT WEEK. TROPICAL STORM LANA...NOW LOCATED FAR
SOUTHEAST OF THE BIG ISLAND...IS STILL EXPECTED TO PASS FAR SOUTH OF
THE AREA ACCORDING TO THE CENTRAL PACIFIC HURRICANE CENTER /CPHC/
LATER THE WEEKEND. THE INTENSITY FORECAST FOR LANA INDICATES IT MAY
WEAKEN TO A TROPICAL DEPRESSION BY SUNDAY AFTERNOON. REGARDLESS...
THE PASSAGE OF THIS LOWER PRESSURE SOUTH OF THE STATE WILL LIKELY
TIGHTEN THE PRESSURE GRADIENT...WHICH WOULD BOOST THE TRADE WIND
SPEEDS. SEE THE LATEST BULLETINS ISSUED BY CPHC FOR THE MORE
DETAILED INFORMATION ON TROPICAL STORM LANA.

WEAK UPPER LEVEL RIDGING IS ALSO EXPECTED TO DEVELOP OVER THE
ISLANDS LATER THIS WEEKEND...WHICH WILL LIKELY MAKE THE AIR MASS
ACROSS THE STATE MORE STABLE. EXPECT TRADE WIND WEATHER TO CONTINUE
ACROSS THE ISLANDS INTO EARLY NEXT WEEK...WITH PASSING CLOUDS AND
SHOWERS AFFECTING WINDWARD AND MAUKA AREAS AT TIMES. ALSO...ANY
SHOWERS THAT AFFECT THE STATE ARE EXPECTED TO REMAIN LIGHT.

&&

.MARINE...
THE SMALL CRAFT ADVISORY /SCA/ CONTINUES FOR THE TYPICALLY WINDY
AREAS OF THE COASTAL WATERS SUCH AS THE PAILOLO AND ALENUIHAHA
CHANNELS...MAALAEA BAY AND THE WATERS SOUTH OF THE BIG ISLAND THIS
MORNING. AS THE PRESSURE GRADIENT ACROSS THE ISLANDS INCREASES DUE
TO THE PASSAGE OF TROPICAL CYCLONE LANA SOUTH OF THE ISLANDS...
ADDITIONAL MARINE ZONES WILL LIKELY NEED TO BE INCLUDED IN THE SCA
FROM TONIGHT THROUGH MONDAY.

THE SIGNIFICANT WAVE HEIGHT AT THE LANAI WAVE BUOY HAS REMAINED JUST
ABOVE 3 FEET WITH A DOMINANT WAVE PERIOD OF 16-17 SECONDS OVERNIGHT.
THEREFORE...SURF HEIGHTS ALONG SOUTH FACING SHORES OF ALL HAWAIIAN
ISLANDS ARE NEAR THE HIGH SURF ADVISORY THRESHOLD OF 8 FEET. THE
LONG PERIOD SOUTH SWELL PRODUCING THESE WAVES IS EXPECTED TO PERSIST
THROUGH THIS WEEKEND...SO THE HIGH SURF ADVISORY REMAINS IN EFFECT
THROUGH SUNDAY AFTERNOON.

&&

.HFO WATCHES/WARNINGS/ADVISORIES...
SMALL CRAFT ADVISORY UNTIL 600 AM HST MONDAY FOR THE PAILOLO AND
ALENUIHAHA CHANNELS...MAALAEA BAY AND THE WATERS SOUTH OF THE BIG
ISLAND.

HIGH SURF ADVISORY UNTIL 600 PM HST SUNDAY FOR SOUTH FACING SHORES
OF ALL HAWAIIAN ISLANDS.

&&

HOUSTON