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Hawaiian Islands Synoptic Discussion and Guidance

556
FXHW60 PHFO 032007
AFDHFO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HONOLULU HI
1007 AM HST MON AUG 3 2015

.SYNOPSIS...
NORTHEAST TRADE WINDS HAVE TAPERED OFF TO MODERATE BREEZES LAST
NIGHT AND SHOULD CONTINUE THROUGH TUESDAY. TROPICAL STORM
GUILLERMO IS FORECAST TO PASS NEAR THE EASTERN PART OF THE STATE
WEDNESDAY...AND CONTINUE TOWARDS THE WESTERN PART OF THE STATE ON
THURSDAY. A MODERATE TO LOCALLY STRONG TRADE WIND FLOW WILL RETURN
FRIDAY AND INTO THE WEEKEND.

&&

.DISCUSSION...
NORTHEAST TRADE WINDS HAVE TAPERED OFF TO MODERATE BREEZES LAST
NIGHT AND SHOULD CONTINUE THROUGH TUESDAY. MEANWHILE...A BROAD
UPPER LVL RIDGE OVER THE AREA WILL KEEP A MOSTLY DRY AND STABLE
AIRMASS IN PLACE THROUGH LATE TUESDAY. HOWEVER...ABUNDANT MOISTURE
HUNG UP ACROSS MAUI AND THE BIG ISLAND WILL BRING CLOUDY SKIES AND
A LITTLE BIT HIGHER CHANCES FOR RAIN FOR THOSE AREA TODAY AND
TUESDAY. SHOWERS WILL BE CONCENTRATED OVER WINDWARD SIDES OF BOTH
ISLANDS...AND ALSO LEEWARD BIG ISLAND FOR JUST THIS AFTERNOON.

THE CENTRAL PACIFIC HURRICANE CENTER /CPHC/ IS TRACKING THE
PROGRESS OF TROPICAL STORM GUILLERMO...LOCATED ABOUT 620 MILES ESE
OF HILO AND MOVING WNW AT 10 MPH. THE CURRENT FORECAST BRINGS THE
CENTER SLIGHTLY NORTH OF THE STATE...BUT MOST OF THE STATE REMAINS
WITHIN THE TRACK/S CONE OF ERROR. GUILLERMO/S INTENSITY IS
FORECAST TO BE TROPICAL STORM STRENGTH. WE DO NOT CURRENTLY HAVE
ANY WATCHES IN EFFECT FOR HAWAII RELATING TO GUILLERMO AT THIS
TIME...BUT THESE MAY BE POSTED LATER TODAY OR TONIGHT DEPENDING ON
THE CPHC ANALYSIS AND MODEL GUIDANCE. IT IS LIKELY THAT HAWAII
WILL FALL AT LEAST WITHIN THE PERIPHERY OF THE STORM AND WOULD
LIKELY SEE RAIN AND WIND ASSOCIATED WITH GUILLERMO. THE INTENSITY
OF BOTH WOULD HIGHLY DEPEND ON GUILLERMO/S EVENTUAL PATH. A
HYDROLOGIC OUTLOOK...SEE PRODUCT ESFHFO ON OUR WEBSITE...HAS BEEN
ISSUED TO OUTLINE THE MID-RANGE FORECAST FLOOD POTENTIAL.

ONCE GUILLERMO CLEARS THE AREA...GLOBAL MODELS ARE IN FAIR AGREEMENT
IN BRINGING BACK A MORE TYPICAL TRADE WIND WEATHER REGIME FOR THE
END OF THE WEEK AND WEEKEND.

&&

.AVIATION...
DEEP RELATIVELY STABLE TRADE WIND FLOW IS EXPECTED TO PERSIST
THROUGH THE EVENING HOURS THEN RELAX OVERNIGHT IN RESPONSE TO THE
APPROACHING TROPICAL SYSTEM. MODERATE LOCALLY BRISK SURFACE WINDS
ARE EXPECTED TO PERSIST INTO EARLY EVENING THEN TAPER OFF BY
MIDNIGHT. AIRMET TANGO FOR MODERATE TURBULENCE IMMEDIATELY SOUTH
THROUGH WEST OF THE ISLANDS WILL LIKELY REMAIN NECESSARY THROUGH
EARLY AFTERNOON. TURBULENCE SHOULD BECOME ISOLATED LATER THIS
AFTERNOON AS SUMMIT LEVEL WINDS ABATE.

SHOWERS WILL CONTINUE TO FAVOR WINDWARD COASTS AND SLOPES...
ESPECIALLY THOSE OF THE BIG ISLAND WHERE TROPICAL LOW LEVEL MOISTURE
PERSISTS. CEILING AND VISIBILITY CONDITIONS ALONG THE EASTERN AND
NORTHEASTERN EXPOSURES WILL CONTINUE TO IMPROVE TODAY...BUT MTN
OBSCURATION IS EXPECTED TO REMAIN A CONCERN FOR ALL WINDWARD AREAS.
EXPECT TO MAINTAIN AIRMET SIERRA FOR MTN OBSCURATION FOR WINDWARD
BIG ISLAND...BUT MAY BE ABLE TO CANCEL CORRESPONDING AIRMET FOR
MAUI.

SEA BREEZE DRIVEN TOWERING CUMULUS WITH TOPS TO FL200 ARE EXPECTED
TO REDEVELOP ALONG LEEWARD COASTS OF THE BIG ISLAND AND MAUI TODAY.
BRIEF MVFR CONDS POSSIBLE IN THE ASSOCIATED SHOWERS...OTHERWISE VFR
CONDS ARE EXPECTED TO PREVAIL ALL LEEWARD AREAS.


&&

.MARINE...
A LARGE EAST-SOUTHEAST SWELL FROM GUILLERMO WILL KEEP HIGH SURF ADVISORY
CONDITIONS ALONG EAST FACING SHORES OF MOST ISLANDS THROUGH
TUESDAY. ASIDE FROM THE BIG ISLAND...SOME EAST FACING SHORES MAY
BE BLOCKED BY ADJACENT ISLANDS TO THE EAST GIVEN THE SWELL
DIRECTION IS NEARLY PARALLEL TO THE ISLAND CHAIN.

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 LATER TODAY IF WE DECIDE TO ISSUE ANY WATCHES
RELATED GUILLERMO. OTHERWISE...THE HIGH SURF ADVISORY WILL BE
EXTENDED OR UPGRADED. ADVERSE EFFECTS FOR ANY OF THE HAWAIIAN
COASTAL AND OFFSHORE WATERS CANNOT NOT BE RULED OUT.


&&

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

&&

$$

DISCUSSION/MARINE...FOSTER
AVIATION...BEDAL


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