AFDHFO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HONOLULU HI
830 PM HST WED MAY 11 2011

.SYNOPSIS...
UNSETTLED WEATHER WILL CONTINUE TO AFFECT MAINLY THE WESTERN ISLANDS
THROUGH THURSDAY AS A WEAK UPPER LEVEL DISTURBANCE BRUSHES PAST THE
WESTERN END OF THE STATE. OTHERWISE MIXED TRADE WIND AND CONVECTIVE
WEATHER IS EXPECTED WITH EAST SOUTHEASTERLY WINDS AND LAND AND SEA
BREEZES THROUGH THE REST OF THE WEEK.

&&

.DISCUSSION...
CONVECTIVE CELLS FIRED UP EARLIER THIS EVENING AFFECTING MAINLY
KAUAI AND OAHU. THERE ARE STILL SOME HEAVY SHOWERS AND THUNDERSTORMS
IN THE VICINITY OF THE WATERS AND KAUAI AND OAHU THIS EVENING...AND
NOT DECREASING ANYTIME SOON. IT LOOKS LIKE THESE CELLS WILL REMAIN
MOSTLY OVER THE WATERS...THOUGH THERE ARE A FEW CELLS JUST SOUTH OF
KAUAI AT THIS HOUR AND WILL PROBABLY AFFECT THE ISLAND IN THE NEXT
COUPLE OF HOURS. THERE ARE ALSO SOME WEAKER CELLS AFFECTING OAHU AS
WELL...THOUGH THESE ARE WEAKER BUT WILL DEFINITELY BRING SOME
LOCALLY HEAVIER SHOWERS TO THE CENTRAL AND WESTERN OAHU THROUGH THE
REST OF THE EVENING. ALTHOUGH A SURFACE HIGH PRESSURE RIDGE IS NEAR
THE ISLANDS...THERE IS STILL A PERSISTENT UPPER LEVEL TROUGH JUST
NORTHWEST OF THE STATE TONIGHT. A WEAK DISTURBANCE RIDING AROUND
THIS UPPER LEVEL TROUGH IS MOVING NEAR THE WESTERN ISLANDS THIS
EVENING...THUS KEEPING THE AIR MASS UNSTABLE FOR THE WESTERN END OF
THE STATE. HIGH CLOUDS FROM THIS TROUGH ARE ALSO AFFECTING THE
ISLANDS AT TIMES...KEEPING SKIES SOMEWHAT CLOUDIER. AT LEAST THE
REST OF THE STATE WILL SEE MAINLY FAIR WEATHER THROUGH THE REST OF
THIS EVENING INTO EARLY THURSDAY MORNING.

LATEST FORECAST CHARTS STILL INDICATE THE UPPER TROUGH WILL LINGER
JUST NORTHWEST OF THE STATE FOR THE REST OF THE WEEK. A SURFACE
TROUGH ASSOCIATED WITH THE UPPER LEVEL TROUGH WILL ALSO PERSIST WEST
OF THE STATE AS WELL. EVEN THOUGH A SURFACE HIGH PRESSURE RESIDES
FAR NORTH OF THE STATE...WINDS REMAIN LIGHT TO MODERATE EAST TO
SOUTHEASTERLY OVER THE ISLANDS DUE TO THE SURFACE TROUGH. IN
FACT...WEAK DISTURBANCES THAT MOVE ALONG THE UPPER LEVEL TROUGH WILL
BRUSH BY THE WESTERN ISLANDS AT TIMES...RESULTING IN THE ATMOSPHERE
BECOMING UNSTABLE OVER THAT AREA. THUS LITTLE CHANGE IS EXPECTED FOR
THE ISLAND WEATHER THROUGH THE REST OF THE WEEK...WITH A HYBRID
TRADE WIND AND CONVECTIVE WEATHER REGIME PREVAILING. LOOK FOR MAINLY
LIGHT EAST TO SOUTHEAST WINDS TO CONTINUE...AND WINDS ARE LIGHT
ENOUGH FOR NIGHT TIME LAND BREEZES AND DAY TIME SEA BREEZES TO
DEVELOP. DAY TIME HEATING WILL FAVOR CLOUDS TO DEVELOP DURING THE
AFTERNOONS...BRINGING SOME SHOWERS OVER THE ISLANDS...WHILE CLOUDS
RIDING WITH THE EASTERLY WINDS WILL AFFECT THE WINDWARD AREAS AT
TIMES. AIR MASS WILL BE UNSTABLE ENOUGH OVER THE WESTERN ISLANDS AND
UPSLOPE BIG ISLAND DURING AFTERNOON FOR POSSIBLE DEEPER CONVECTION
TO DEVELOP...THUS BRINGING HEAVIER SHOWERS AND EVEN A SLIGHT CHANCE
OF THUNDERSTORMS. THE ISLANDS MAY SEE SOME CLEARING AT NIGHT...BUT
THEN HIGH CLOUDS FROM THE PERSISTENT UPPER LEVEL TROUGH MAY KEEP
SKIES CLOUDIER AT TIMES.

&&

.MARINE...
WEATHER WILL REMAIN UNSETTLED AT TIMES OVER THE COASTAL WATERS OF
THE KAUAI AND OAHU. MAY HAVE TO CONTINUE THE MARINE WEATHER
STATEMENT THURSDAY DUE TO THE POSSIBLE THUNDERSTORMS AS WELL AS
LOCALLY HEAVY RAIN. ANY THUNDERSTORMS MAY PRODUCE DANGEROUS
LIGHTNING...WATERSPOUTS AND BRIEF PERIODS OF ROUGH HIGHER SEAS.

&&

.AVIATION...
MAINLY VFR CONDITIONS WILL PREVAIL OVER MUCH OF THE SITES TONIGHT.
ON THE OTHER HAND...THERE ARE ISOL MVFR OR EVEN IFR CONDITIONS IN
THE KAUAI AND OAHU VICINITY DUE TO ISOL TS WITH TOPS OVER 35
THOUSAND FEET.

&&

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

&&

$$