Drought in Hawaii, July 1 to 31, 2008

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HONOLULU HI
830 PM HST MON JUN 30 2008

.SYNOPSIS...
PREVAILING WINDS WILL BE LIGHT INTO WEDNESDAY...ALLOWING LOCAL SEA
BREEZES TO BUILD UP CLOUDS AND PERHAPS A SHOWER OR TWO INLAND EACH
AFTERNOON. HIGH PRESSURE REBUILDING NORTH OF HAWAII WILL BRING BACK
LIGHT TRADE WINDS BY THE WEEKEND...WITH MOST CLOUDS RETURNING TO
WINDWARD SLOPES.

&&

.DISCUSSION...
A DISSIPATING CLOUD BAND ASSOCIATED WITH A RAPIDLY WEAKENING FRONT
PUSHED SOUTH ONTO KAUAI...AND APPROACHED OAHU. ALTHOUGH THE SURGE OF
COLD AIR BEHIND THIS FEATURE HAD ACHIEVED SOMETHING OF A MINOR
MIRACLE IN BRINGING THE FRONT TO THE MAIN HAWAIIAN ISLANDS DURING
THIS TIME OF YEAR...IT ALSO HAD SPENT ALMOST ALL OF ITS ENERGY IN
BREAKING DOWN THE SUBTROPICAL RIDGE...SO NOW THE FRONTAL CLOUD BAND
REPRESENTED LITTLE MORE THAN A CHANGE IN AIR MASS...AND A SHIFT FROM
WEAK NORTHEASTERLY WINDS TO WEAK NORTHERLIES. THE CLOUD BAND DID
POSSESS A MODICUM OF ATMOSPHERIC MOISTURE...BUT SANDWICHED AS IT WAS
BETWEEN TWO RELATIVELY DRY AIR MASSES...THIS MOISTURE WILL HAVE
LITTLE CHANCE TO PRECIPITATE.

RADAR DATA SHOWED ONLY THE SLIGHTEST HINTS OF ECHOES IN THE
APPROACHING CLOUD BAND. HOWEVER...THE KAUAI RADAR HAS POOR COVERAGE
TO THE NORTH...AND THE CLOUD BAND STILL WAS RATHER FAR FROM OAHU. IN
THE FINAL ANALYSIS...SURFACE OBSERVATIONS WILL BE THE BEST
INDICATORS OF THE RAINFALL POTENTIAL OF THE CLOUD BAND...BUT FOR NOW
ISOLATED LIGHT SHOWERS APPEAR TO BE THE BEST FORECAST FOR IT.

IT IS TRUE THAT A COMPACT MID-LEVEL LOW HUGGED THE SOUTH EDGE OF
THE RIDGE NEAR KAUAI...AND THAT GUIDANCE PREDICTS MORE SUCH LOWS TO
DEVELOP OR PASS SOUTH OF THE AREA THROUGH MOST OF THE FORECAST
PERIOD. HOWEVER...THESE LOWS WILL NOT EXTEND FAR ENOUGH NORTH TO
AFFECT THE ISLANDS MUCH...WHERE THE MID-LEVEL RIDGING WILL PREVAIL.

FROM WEDNESDAY INTO NEXT WEEKEND...THE SUBTROPICAL RIDGE WILL
REBUILD...ALLOWING TRADE WINDS TO START UP AGAIN. HOWEVER...GUIDANCE
DOES NOT EXPECT THESE TO GET ESPECIALLY STRONG...SO LOCAL DIURNAL
CIRCULATIONS MAY REMAIN SIGNIFICANT.

LIGHT TRANSPORT WINDS WILL MAKE IT DIFFICULT FOR VOLCANIC EMISSIONS
TO LEAVE THE BIG ISLAND. THE GFS AND NOGAPS BOTH SHOW A PERSISTENT
NORTHEASTERLY TRANSPORT WIND...ALTHOUGH THE MUCH LIGHTER GFS APPEARS
TO BE MORE REPRESENTATIVE THAN THE STRONGER NOGAPS. ONCE THE SUN
SETS AND THE UPSLOPE FLOW TRANSITIONS TO DOWNSLOPE...THE EMISSIONS
BUILDING UP NEAR THE VENT SHOULD DIMINISH AS THEY DID LAST NIGHT.
THE STRONGER NORTHEASTERLY WIND BROUGHT BY THE BUILDING RIDGE WILL
BE SLOW IN SPREADING SOUTH ALONG THE ARCHIPELAGO TO THE BIG
ISLAND...SO TRANSPORT WINDS ACROSS THE VOLCANO AREA MAY REMAIN LIGHT
THROUGH THURSDAY.

&&

.MARINE...
SMALL SWELLS WILL CONTINUE TO ROLL IN FROM THE SOUTH SOUTHWEST THIS
WEEK. AN UNSEASONABLE SWELL FROM THE NORTH NORTHWEST WILL PERSIST
THROUGH WEDNESDAY. LIGHT WINDS OVER THE COASTAL WATERS WILL RESULT
IN SMALL SEAS THROUGH WEDNESDAY.

&&

.HFO WATCHES/WARNINGS/ADVISORIES...
NONE.

&&

RYSHKO