Wind Advisory 24, NWS Honolulu, HI

488 
WWHW70 PHFO 230557
NPWHFO

URGENT - WEATHER MESSAGE
NATIONAL WEATHER SERVICE HONOLULU HI
757 PM HST FRI MAR 22 2013

HIZ028-230700-
/O.CAN.PHFO.WI.Y.0024.000000T0000Z-130323T1600Z/
BIG ISLAND SUMMITS-
INCLUDING THE CITY OF...MAUNA LOA AND MAUNA KEA ABOVE 8000 FEET
757 PM HST FRI MAR 22 2013

...WIND ADVISORY IS CANCELLED...

THE NATIONAL WEATHER SERVICE IN HONOLULU HAS CANCELLED THE WIND
ADVISORY. 

WINDS HAVE EASED TO BELOW ADVISORY LEVELS AT THE SUMMITS OF MAUNA
LOA AND MAUNA KEA.

$$

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HONOLULU HI
1002 AM HST FRI MAR 22 2013

.SYNOPSIS...
A WEAKENING COLD FRONT WILL MOVE ACROSS OAHU TODAY AND STALL NEAR
MAUI COUNTY LATE TONIGHT. THE FRONT WILL WEAKEN TO A TROUGH AND
WILL GRADUALLY SHIFT BACK TO THE WEST OVER THE WEEKEND. THIS WILL
KEEP THE WEATHER SOMEWHAT UNSETTLED...ESPECIALLY OVER THE WESTERN
ISLANDS...FOR THE NEXT FEW DAYS.

&&

.DISCUSSION...
A WEAKENING COLD FRONT NEAR OAHU HAS ENOUGH REMNANT MOISTURE AND
LOW LEVEL CONVERGENCE TO GENERATE A BAND OF MODERATE TO LOCALLY
HEAVY SHOWERS WHICH IS APPROACHING OAHU THIS HOUR. LEGACY AND DUAL
POLARIZATION RAINFALL ESTIMATES WITHIN THE BAND HAVE BEEN A
QUARTER TO HALF INCH...SO WHILE THERE COULD BE A FEW QUICK
DOWNPOURS...NOTHING TOO HEAVY IS EXPECTED. HAVE UPDATED TIMING
FOR POP AND WEATHER GRIDS AS WELL AS ADJUSTMENTS TO QPF GRIDS.

NOW THAT A MID LEVEL SHORTWAVE IS LIFTING AWAY OFF TO THE N...WINDS
AT THE SUMMITS OF MAUNA KEA AND MAUNA LOA HAVE DROPPED AND SO WE
HAVE CANCELLED THE WIND ADVISORY A FEW HOURS EARLY.

THERE IS SURPRISINGLY DECENT AGREEMENT AMONG THE MODELS ABOUT THE
BEHAVIOR OF THIS REMNANT FRONTAL BAND OVER THE NEXT FEW DAYS.
WHILE THIS IS NO GUARANTEE...IT DOES HELP TO REINFORCE FORECAST
CONFIDENCE IN THE SCENARIO. THE FRONT...OR WHAT REMAINS OF
IT...SHOULD STALL NEAR MAUI COUNTY LATE TONIGHT...THEN START TO
SHIFT BACK TO THE W ON SAT. WITHOUT SIGNIFICANT UPPER LEVEL
SUPPORT...THE SHOWER COVERAGE WITH THIS FEATURE SHOULD GRADUALLY
DIMINISH LATER TODAY AND SAT.

HOWEVER...MODELS ARE SHOWING ANOTHER WEAKER MID-LEVEL SHORTWAVE
DEVELOPING W OF THE ISLANDS SAT NIGHT AND MOVING NE ACROSS THE
STATE ON SUN. THIS WILL TEMPORARILY HELP TO REINFORCE THE SURFACE
BOUNDARY...AT THAT TIME EXPECTED TO BE JUST A TROUGH...AS IT
PUSHES BACK SLOWLY TO THE W. THUS...EXPECTING SHOWER COVERAGE TO
INCREASE ONCE AGAIN ALONG AND AROUND THE DIFFUSE BOUNDARY SAT
NIGHT AND SUN. CURRENTLY MAKING ADJUSTMENTS TO THE SKY/POP/WX
GRIDS TO MATCH THIS SCENARIO. IT/S NOT GOING TO BE A WASHOUT
WEEKEND BUT SOMEWHAT CLOUDIER AND WETTER THAN USUAL...MAINLY FOR
KAUAI AND OAHU. THE PROXIMITY OF THE TROUGH WILL KEEP WINDS ON THE
LIGHTER SIDE AS WELL...AND MORE ESE THAN TRADES FOR MOST PLACES.

AFTER THE NEXT BATCH OF SHORTWAVE ENERGY LIFTS OUT EARLY NEXT
WEEK...YET ANOTHER MID-LEVEL TROUGH IS PROGGED TO DIG NEAR THE
ISLANDS ABOUT TUE...AND THE LOCAL AIRMASS WILL DESTABILIZE YET
AGAIN. THERE WILL LIKELY BE ANOTHER REINVIGORATION OF SHOWERS NEAR
THE TROUGH AROUND THAT TIME...BUT IT IS DIFFICULT TO SAY WHERE
EXACTLY THE TROUGH WILL BE. THE BEST CHANCE FOR ENHANCEMENT WILL
BE NEAR KAUAI ON TUE. THE OTHER ISLANDS WILL LIKELY BE IN MORE
TYPICAL TRADE WIND WEATHER WITH HIGH PRESSURE BUILDING TO THE
NORTH.

&&

.AVIATION...
A WEAK FRONT IN KAUAI CHANNEL AND A SERIES OF PREFRONTAL CONVERGENCE
BANDS WILL PRODUCE WIDESPREAD MVFR AND ISOLATED IFR CONDITIONS FROM
THE KAUAI CHANNEL TO MAUI COUNTY TODAY. THESE CONDITIONS MAY PERSIST
THROUGH SATURDAY AS THE FRONT STALLS AND WEAKENS TO A TROUGH.

LIGHT SOUTHEAST FLOW OVER MAUI AND THE BIG ISLAND WILL ALLOW CLOUDS
AND SHOWERS TO FORM OVER THE SLOPES IN THE AFTERNOON WITH WIDESPREAD
MVFR AND ISOLATED IFR CONDITIONS. THE CLOUDS AND SHOWERS WILL LIKELY
DISSIPATE OVERNIGHT AND REFORM SATURDAY AFTERNOON.

&&

.MARINE...
THE CURRENT NW SWELL IS EXPECTED TO CONTINUE TO DIMINISH. THE
MODELS ARE IN GOOD AGREEMENT WITH THE HANDLING OF THE CURRENT LOW
OFF KAMCHATKA AND THIS LENDS SUPPORT FOR THE WAVEWATCH III
SOLUTION SHOWING THE NEXT MODERATE SWELL ARRIVING LATE SUNDAY
NIGHT...AND PEAKING MONDAY. THIS SWELL WILL PROBABLY STAY BELOW
ADVISORY LEVELS.

&&

.HFO WATCHES/WARNINGS/ADVISORIES...
HIGH SURF ADVISORY UNTIL 6 AM HST SATURDAY FOR NIIHAU-KAUAI
WINDWARD-KAUAI LEEWARD-WAIANAE COAST-OAHU NORTH SHORE-OAHU
KOOLAU-MOLOKAI-MAUI WINDWARD WEST-MAUI CENTRAL VALLEY-WINDWARD
HALEAKALA-KONA-KOHALA.

&&

DISCUSSION/MARINE...R BALLARD
AVIATION...DONALDSON