Area Forecast Discussion
Issued by NWS Honolulu, HI

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140
FXHW60 PHFO 061410
AFDHFO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HONOLULU HI
410 AM HST FRI MAY 6 2016

.SYNOPSIS...
A BIT OF UNSETTLE WEATHER IS EXPECTED FOR PARTS OF THE STATE FOR
NEXT COUPLE OF DAYS AS A LATE SEASON COLD FRONT MAKES IT WAY DOWN
THE ISLAND CHAIN. THE FRONT IS EXPECTED TO REACH KAUAI LATE FRIDAY
AFTERNOON AND CONTINUE SLOWLY EASTWARD...REACHING MAUI COUNTY
SATURDAY MORNING. THE FRONT IS EXPECTED TO STALL OVER THE EASTERN
END OF THE ISLAND CHAIN OVER THE WEEKEND. THE WESTERN ISLANDS WILL
BE UNDER THE INFLUENCE OF A TYPICAL TRADE WIND REGIME.

&&

.DISCUSSION...
A WEAKENING COLD FRONT IS LOCATED ABOUT 320 MILES NORTHWEST OF KAUAI
AT 3 AM HST. IT CONTINUES TO PRESS EAST AND SOUTHEASTWARD TOWARD THE
MAIN HAWAIIAN ISLANDS. IT IS EXPECTED TO REACH KAUAI LATE THIS
AFTERNOON. THE FRONT WEAKENS TO A POINT WHERE IT BECOMES DIFFICULT TO
IDENTIFY AS IT APPROACHES OAHU AT AROUND MIDNIGHT. THE ECMWF AND GFS
ARE IN GOOD AGREEMENT WITH A SLOW DRAG EASTWARD ONCE IT REACHES OAHU.
THE FRONT IS TABBED TO REACH MOLOKAI SHORTLY AFTER DAY BREAK
SATURDAY...THEN TO THE REST OF MAUI COUNTY LATER IN THE MORNING.
THE FRONT CONTINUES SLOWLY ON TO THE BIG ISLAND THE REST OF THE
DAY AND EVENING...FINALLY STALLING OVER THE BIG ISLAND SUNDAY. THE
LATEST MODEL RUN SUGGESTS THE FRONT SETTLES OVER THE BIG ISLAND
WITH THE BACK EDGE OF THE FRONT CATCHING EASTERN MAUI. CURRENT
GRIDS HAVE THE FRONT CLEARING MAUI SO THIS PART MAY NEED UPDATING
SHOULD THE MODELS CONTINUES WITH ITS LATEST PROJECTION. MODELS
ARE ALSO SHOWING A TROUGH THAT FORMS AHEAD OF THE FRONT TODAY...AND
MOVES EASTWARD STAYING AHEAD OF THE FRONT. THIS TROUGH SUBSEQUENTLY
DISSIPATE SUNDAY NIGHT NORTH OF THE BIG ISLAND.

BEHIND THE FRONT IS A TYPICAL TRADE WIND REGIME WITH SHOWERS FAVORING
THE WINDWARD AND MOUNTAIN AREAS. THE MODELS ARE SHOWING A BAND OF
SHOWERS FORMING NORTH OF THE ISLANDS SUNDAY AND SETTLING OVER THE
NORTHERN ISLANDS TUESDAY NIGHT.

THOSE LATE AFTERNOON EVENING SHOWERS OVER OAHU HAVE FINALLY ENDED.
SKIES OVER KAUAI IS NOW FAIR AFTER A SHOWER MOVED THROUGH ITS
WESTERN PORTION JUST A COUPLE OF HOURS AGO. SHOWERS ARE NOW PRESENT
TO THE WEST AND SOUTHWEST OF KAUAI...THE KAIWI CHANNEL...SOUTH OF
LANAI...AND OFF THE BIG ISLAND/S HAMAKUA AND KONA COASTS. THE
SHOWERS NEAR LANAI POSES AN IMMEDIATE THREAT TO OAHU...MOLOKAI...AND
LANAI. ISOLATED SHOWERS FOR THESE ISLANDS SHOULD COVER IT FOR THE
MORNING PORTION. LOCALLY...BRIEF...HEAVY SHOWERS ARE A GOOD BET
THIS AFTERNOON FOR ALL ISLANDS AS THESE SHOWERS GET A BOOST FROM AN
APPROACHING UPPER LEVEL TROUGH.

THE CURRENT WINDFLOW IS BASICALLY SOUTH FROM OAHU WESTWARD. LATER
THIS AFTERNOON...THESE WINDS WILL TURN WESTERLY. THE SHOWERS
SOUTH OF LANAI IS FOLLOWING THE WINDS OF A SMALL EDDY THAT IS
MOVING CLOCKWISE. THIS EDDY SHOULD DISSIPATE THIS AFTERNOON. A
SOUTHEAST WIND FLOW REMAINS FIRM OVER THE WINDWARD WATER OF MAUI
AND THE BIG ISLAND. BUT STARTING THIS AFTERNOON....THE WINDS WILL
TURN VARIABLE IN ASSOCIATION WITH A TROUGH.


&&

.AVIATION...
AN APPROACHING FRONT FROM THE NORTHWEST WILL MAKE THE ATMOSPHERE
INCREASINGLY UNSTABLE THROUGH THE DAY. ACROSS THE STATE...THE
GREATEST CHANCE FOR SHOWERY MVFR CEILINGS AND VISIBILITIES OVER
INTERIOR AND MAUKA SECTIONS WILL BE IN THE AFTERNOON.

NO AIRMETS ARE CURRENTLY IN EFFECT.

&&

.MARINE...
A SMALL WEST NORTHWEST SWELL WILL PERSIST THROUGH TODAY. A
REINFORCING SMALL TO MODERATE SIZE NORTH NORTHWEST SWELL WILL
ARRIVE TONIGHT AND LAST THROUGH THE WEEKEND. THE 3 FOOT SWELL
FROM THE SOUTH IS HERE. THEY ARE PRESENT AT OUR COASTAL
BUOYS...BARBERS POINT AND LANAI. THE PERIOD IS 13 SECONDS.
BUOY 51003 LOCATED SOME 240 MILES SOUTHWEST OF OAHU IS SHOWING A
5.5 FOOT SWELL. MOST OF THIS 5.5 FEET IS LIKELY FROM THE SOUTH.
WE WILL CONTINUE TO WATCH CLOSELY THESE BUOYS. THERE IS AN OUTSIDE
CHANCE THIS SWELL IS LARGER. IF SO IT WILL BE HIGH SURF ADVISORY
FOR THE SOUTH FACING SHORES.

TRADE WIND SPEEDS BEHIND THE FRONT ARE MARGINAL AT BEST AT THIS
POINT AS PER GFS AND ECMWF MODELS. THEY WILL BE MONITORED
CLOSELY...AND WE WILL PROMPTLY DISH OUT THE SMALL CRAFT ADVISORY
IF NEEDED.

&&

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

&&

$$

DISCUSSION/MARINE...LAU
AVIATION...KINEL

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