Drought in Hawaii, August 1 to 31, 2009

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HONOLULU HI
830 PM HST FRI JUL 31 2009

.SYNOPSIS...
HIGH PRESSURE LOCATED FAR NORTHEAST OF THE ALOHA STATE WILL MAINTAIN
TRADE WINDS THROUGH EARLY NEXT WEEK. THE TRADE WIND SPEEDS MAY
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 37N 146W...OR ABOUT 1300 MILES
NORTHEAST OF HONOLULU...REMAINS NEARLY STATIONARY THIS EVENING. THE
PRESSURE GRADIENT SOUTH OF THIS FEATURE IS MAINTAINING TRADE WINDS
ACROSS THE STATE. IN ADDITION TO THE HIGH AT THE SURFACE...AN UPPER
TROPOSPHERIC LOW LOCATED JUST NORTH OF THE ISLANDS CONTINUES TO MOVE
SLOWLY NORTHWARD. THE CLOSE PROXIMITY OF THIS FEATURE ALOFT TO THE
ISLANDS WILL KEEP THE ATMOSPHERE OVER THE STATE SLIGHTLY UNSTABLE...
AT LEAST THROUGH TONIGHT. THEREFORE...EXPECT PASSING SHOWERS TO
AFFECT THE ISLANDS AT TIMES THROUGH SATURDAY...ESPECIALLY OVER
WINDWARD AND MAUKA AREAS.

SURFACE HIGH PRESSURE WILL PREVAIL FAR NORTHEAST OF THE ALOHA STATE
FROM THIS WEEKEND 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 DEPRESSION BY SATURDAY NIGHT
OR SUNDAY. 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 DURING THE WEEKEND...WHICH WILL LIKELY MAKE THE AIR MASS
ACROSS THE STATE MORE STABLE. THEREFORE...THE SHOWERS ARE EXPECTED
TO REMAIN LIGHT. AS NOTED IN THE PREVIOUS DISCUSSION...TRADE WIND
WEATHER WILL CONTINUE TO REIGN OVER THE ISLANDS FROM THIS WEEKEND
INTO EARLY NEXT WEEK...WITH PASSING CLOUDS AND SHOWERS AFFECTING
WINDWARD AND MAUKA AREAS AT TIMES.

&&

.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 EARLY
THIS EVENING. AS THE PRESSURE GRADIENT ACROSS THE ISLANDS INCREASES
DUE TO THE PASSAGE OF TROPICAL CYCLONE LANA SOUTH OF THE ISLANDS...
ADDITIONAL MARINE ZONES MAY NEED TO BE INCLUDED IN THE SCA FROM
SATURDAY NIGHT THROUGH MONDAY.

THE SIGNIFICANT WAVE HEIGHT AT THE LANAI WAVE BUOY HAS INCREASED TO
3.5 FEET WITH A DOMINANT WAVE PERIOD OF 17 SECONDS. THE KILO NALU
WAVE SENSOR LOCATED ALONG THE SOUTH SHORE OF OAHU HAS A SIGNIFICANT
WAVE HEIGHT OF ABOUT 3 FEET WITH A WAVE PERIOD OF 17 SECONDS.
THEREFORE...SURF HEIGHTS ALONG SOUTH FACING SHORES OF ALL HAWAIIAN
ISLANDS REMAIN NEAR THE HIGH SURF ADVISORY THRESHOLD OF 8 FEET. THIS
SWELL 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