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Hawaiian Islands Synoptic Discussion and Guidance

977
FXHW60 PHFO 022133 AAA
AFDHFO

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE HONOLULU HI
1133 AM HST SUN AUG 2 2015

.UPDATE...
MINOR CHANGES TO THE WIND FORECAST ON FROM TUESDAY NIGHT THROUGH
THURSDAY NIGHT FOR HURRICANE GUILLERMO/S 11 AM HST ADJUSTED TRACK
AND INTENSITY.


&&

.SYNOPSIS...
MODERATE TO FRESH TRADES BROUGHT ON BY A PASSING DISTURBANCE SOUTH
OF THE ISLANDS WILL CONTINUE THROUGH THIS EVENING BEFORE EASING OFF
TO MODERATE SPEEDS MONDAY AND TUESDAY. SHOWERS WILL BE MOSTLY
CONCENTRATED OVER THE WINDWARD BIG ISLAND TODAY AND TONIGHT. THE TRADE
FLOW IS LIKELY TO BE INTERRUPTED BY THE CIRCULATION OF TROPICAL
CYCLONE GUILLERMO AND ITS ASSOCIATED MOISTURE BETWEEN TUESDAY
NIGHT AND THURSDAY. A MODERATE TO LOCALLY STRONG TRADE WIND FLOW
WILL RESUME FRIDAY INTO THE WEEKEND.

&&

.PREV DISCUSSION.../ISSUED 1000 AM HST SUN AUG 2 2015/

MODERATE TO FRESH TRADES BROUGHT ON BY A PASSING DISTURBANCE SOUTH
OF THE ISLANDS WILL CONTINUE THROUGH THIS EVENING BEFORE EASING OFF
TO MODERATE SPEEDS MONDAY AND TUESDAY. UPPER LEVEL RIDGING OVER
THE ISLANDS WILL KEEP CONDITIONS MOSTLY DRY AND STABLE OVER THE
NEXT COUPLE OF DAYS. THE ONLY EXCEPTION TO THIS IS ON THE WINDWARD
SIDE OF THE BIG ISLAND WHERE A BAND OF CLOUDS AND SHOWERS ORIENTED
WITH THE TRADE WINDS WILL CONTINUE TO FUNNEL IN THROUGH MONDAY.
SHOWERS WILL REMAIN ON THE LIGHT SIDE FOR WINDWARD BIG ISLAND.

SUBSIDENCE AHEAD OF APPROACHING HURRICANE GUILLERMO MAY
OCCUR ON TUESDAY WHICH MEANS THINNING OUT THE REMNANT MOISTURE
FROM THE BIG ISLAND...AND CONTINUING THE DRY CONDITIONS FOR ALL
OTHER ISLANDS.

THE REST OF THE FORECAST PACKAGE WILL REST ON THE TRACK OF
GUILLERMO. BASED ON THE LATEST ON THE 5 AM HST FORECAST ADVISORY
ISSUED BY THE CENTRAL PACIFIC HURRICANE CENTER...GUILLERMO IS FORECAST
TO BE WEAKEN TO A TROPICAL STORM AS IT APPROACHES HAWAII FROM THE
EAST SOUTHEAST LATE TUESDAY NIGHT / EARLY WEDNESDAY MORNING.
GUILLERMO IS EXPECTED TO MOVE ON A WEST NORTHWEST PATH NEAR OR
OVER THE SMALLER ISLANDS THROUGH THURSDAY NIGHT. EXPECT WIDESPREAD
RAIN AND PERIODS OF STRONG WINDS DURING THIS STRETCH. MORE SPECIFIC
DETAILS OF FLOOD...WIND AND THUNDERSTORM HAZARDS ASSOCIATED WITH
GUILLERMO WOULD BE DETERMINED IN THE NEXT DAY OR SO IF / WHEN WE
DECIDE TO ISSUE WATCHES AND SUBSEQUENT WARNINGS.

AFTER THE PASSAGE OF GUILLERMO...MODELS ARE LOOKING AT A MORE
TYPICAL MODERATE TO LOCALLY STRONG TRADE WIND PATTERN FOR THE
UPCOMING WEEKEND.


&&

.AVIATION...
VFR CONDITIONS PREVAIL AT MOST TAF SITES WITH THE EXCEPTION OF PHTO
WHERE THERE HAS BEEN OCCASIONAL MVFR CONDITIONS BEING REPORTED DUE
TO LOW CLOUDS AND SHRA. EXPECT THESE CONDITIONS TO CONTINUE THROUGH
THE DAY TODAY. AIRMET SIERRA REMAINS POSTED ALONG THE WINDWARD
SLOPES OF THE BIG ISLAND DUE TO LOW CLOUDS AND SHRA. THERE MAY ALSO
BE SOME LOCAL MVFR CONDITIONS OVER WINDWARD SLOPES OF THE SMALLER
ISLANDS AS WELL. AIRMET TANGO REMAINS POSTED FOR LOW LEVEL
TURBULENCE DUE TO MODERATE TO FRESH TRADE WINDS. WINDS ARE EXPECTED
TO GRADUALLY DIMINISH BEGINNING TONIGHT.


&&

.MARINE...
THE SMALL CRAFT ADVISORY /SCA/ CONTINUES THROUGH 6 AM HST MONDAY.
MODELS KEEP SCA STRENGTH TRADE WINDS INTO THE FIRST HALF OF THE
NIGHT TONIGHT BEFORE EASING OFF.

GUILLERMO IS FORECAST TO REACH OUR OFFSHORE WATERS SOME 270 MILES
EAST SOUTHEAST OF THE BIG ISLAND TUESDAY AFTERNOON AT TROPICAL
STORM STRENGTH AND CONTINUE AT THIS STRENGTH AS IT NEARS THE
ISLANDS. ALTHOUGH THE TRACK AND INTENSITY OF THE TROPICAL CYCLONE
REMAINS UNCERTAIN AT THIS POINT...ADVERSE EFFECTS FOR HAWAIIAN
COASTAL WATERS CANNOT NOT BE RULED OUT.

GUILLERMO HAS GENERATED A LARGE EAST SWELL AIMED TOWARDS THE
ISLANDS. BUOY 51004...LOCATED AROUND 230 MILES SOUTHEAST OF THE
BIG ISLAND...HAS PICKED UP ON SOME OF THE HIGHER ENERGY FORRUNNER
WAVES HEADED THIS WAY. A HIGH SURF ADVISORY WILL GO INTO EFFECT AT
12 NOON TODAY FOR THE EAST FACING SHORES OF MOST ISLANDS AND
CONTINUES THROUGH TUESDAY. ADVISORY LEVEL SURF SHOULD BE REACH THE
BIG ISLAND FIRST BY LATE THIS AFTERNOON AND SPREAD WEST TO THE
REMAINING ISLANDS TONIGHT AND MONDAY. THE SURF SHOULD PEAK MONDAY
NIGHT FOLLOWED BY A GRADUAL DECLINE THROUGH TUESDAY. THE EFFECTS
OF GUILLERMO WILL LIKELY BOOST LOCALLY GENERATED WIND WAVES AND
SURGE TUESDAY NIGHT / WEDNESDAY THROUGH THURSDAY. MORE SPECIFIC
DETAILS OF MARINE HAZARDS ASSOCIATED WITH GUILLERMO WOULD BE
DETERMINED IN THE NEXT DAY OR SO IF / WHEN WE DECIDE TO ISSUE
WATCHES AND SUBSEQUENT WARNINGS.


&&

.HFO WATCHES/WARNINGS/ADVISORIES...
HIGH SURF ADVISORY FROM NOON TODAY TO 6 PM HST TUESDAY FOR EAST
FACING SHORES OF KAUAI OAHU MOLOKAI MAUI AND THE BIG ISLAND.

SMALL CRAFT ADVISORY UNTIL 6 AM HST MONDAY FOR OAHU LEEWARD
WATERS-KAIWI CHANNEL-MAALAEA BAY-PAILOLO CHANNEL-ALENUIHAHA
CHANNEL-BIG ISLAND LEEWARD WATERS-BIG ISLAND SOUTHEAST WATERS.


&&

$$

UPDATE/PREVIOUS DISCUSSION/MARINE...FOSTER
AVIATION...BURKE


Bulletins, Forecasts and Observations are courtesy of Honolulu National Weather Service Forecast Office