Area Forecast Discussion
Issued by NWS Honolulu, HI

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000
FXHW60 PHFO 310145
AFDHFO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HONOLULU HI
400 PM HST THU JUL 30 2015

.SYNOPSIS...
HIGH PRESSURE FAR NORTHEAST OF THE STATE AND A SERIES OF WEAK
TROPICAL DISTURBANCES PASSING TO THE SOUTH WILL MAINTAIN LOCALLY
BREEZY TRADE WINDS THROUGH THE WEEKEND. THE TRADES WILL BRING SOME
SHOWERS TO WINDWARD AREAS...MOSTLY DURING NIGHTS AND MORNINGS.
REMNANT MOISTURE FROM A FORMER TROPICAL DEPRESSION WILL REACH US
THIS WEEKEND...BRINGING MUGGY WEATHER AND INCREASED SHOWERS FOR
WINDWARD AREAS...ESPECIALLY FOR THE BIG ISLAND.

&&

.DISCUSSION...
WATER VAPOR IMAGERY SHOWS AN UPPER LEVEL HIGH SOUTHEAST OF THE
STATE...WITH A RIDGE EXTENDING OVER THE ISLANDS. AT THE SURFACE...
HIGH PRESSURE IS LOCATED FAR NORTHEAST OF THE STATE. THE REMNANT LOW
THAT WAS TROPICAL DEPRESSION EIGHT-E IS LOCATED FAR EAST OF THE BIG
ISLAND...AND TROPICAL STORM GUILLERMO IS FARTHER TO THE
EAST-SOUTHEAST. 00Z SOUNDINGS FROM HILO AND LIHUE SHOWED INVERSIONS
AROUND 6KFT AND PRECIPITABLE WATERS AROUND 1.4 INCHES. EARLY
AFTERNOON TOTAL PRECIPITABLE WATER IMAGERY SHOWS SIMILAR TO SLIGHTLY
HIGHER VALUES OVER AND UPSTREAM OF THE STATE...WITH MUCH HIGHER
VALUES IN EXCESS OF 2 INCHES CENTERED AROUND 140W ASSOCIATED WITH
THE FORMER TROPICAL DEPRESSION.

A TYPICAL TRADE WIND PASTERN IS EXPECTED FOR THE NEXT COUPLE DAYS.
BETWEEN THE HIGH TO THE NORTHEAST AND A TROUGH PASSING FAR SOUTH OF
THE STATE...THE GRADIENT ACROSS THE ISLANDS WILL SUPPORT LOCALLY
BREEZY TRADE WINDS. SHOWERS HAVE BEEN FOCUSED ACROSS WINDWARD
SECTIONS...WITH RAINFALL AMOUNTS GENERALLY A TENTH OF AN INCH OR
LESS OVER THE PAST 12 HOURS. FORECAST SOUNDINGS/TIME SECTIONS SHOW
INVERSIONS AND MOISTURE DEPTH REMAINING STEADY...AND A SIMILAR
WEATHER PATTERN IS EXPECTED THROUGH FRIDAY NIGHT. SHOWERS WILL BE
FOCUSED MAINLY ACROSS WINDWARD SECTIONS...GREATEST AT NIGHT AND
DURING THE MORNING...WITH SOME SHOWERS ACROSS LEEWARD BIG ISLAND AND
MAUI DURING THE AFTERNOON.

FORMER TROPICAL DEPRESSION EIGHT-E IS EXPECTED TO MOVE
WEST-SOUTHWEST AND PASS BY SOUTH OF THE STATE OVER THE WEEKEND. THE
MAIN IMPACT EXPECTED FOR HAWAII WILL BE AN INCREASE IN MOISTURE...AS
WELL AS A CONTINUED ENHANCEMENT TO THE TRADE WINDS. THE BULK OF THE
MOISTURE ASSOCIATED WITH THE FORMER DEPRESSION WILL REMAIN SOUTHEAST
OF THE STATE...THOUGH WITH PW VALUES NEAR 2 INCHES REACHING EAST AND
SOUTHEAST SECTIONS OF THE BIG ISLAND. THERE IS THE POTENTIAL FOR
SOME OF THIS DEEPER TROPICAL MOISTURE TO SPREAD TO THE SMALLER
ISLANDS AS WELL...BUT 12Z/18Z GFS/ECMWF HAVE BACKED AWAY FROM THIS
AND NOW FOCUS THE BULK OF THE SHOWERS FROM THE BIG ISLAND SOUTHWARD.
MOISTURE DEPTH WILL LIKELY EXTEND UP TO SUMMIT LEVEL...THOUGH
TEMPERATURES ARE EXPECTED TO REMAIN ABOVE FREEZING THROUGH THE
PERIOD.

THE NATIONAL HURRICANE CENTER IN MIAMI IS ISSUING BULLETINS ON
TROPICAL STORM GUILLERMO...WHICH IS NEARLY 2000 MILES EAST-SOUTHEAST
OF HILO. THE CURRENT FORECAST IS FOR GUILLERMO TO MOVE
WEST-NORTHWEST AND STRENGTHEN...POTENTIALLY CROSSING 140W INTO THE
CENTRAL PACIFIC HURRICANE CENTER AREA OF RESPONSIBILITY ON SATURDAY.
IMPACTS TO HAWAII WILL BE VERY DEPENDENT UPON THE TRACK AND SPEED OF
THE SYSTEM...WHICH IS HIGHLY UNCERTAIN THIS FAR OUT IN TIME.

&&

.AVIATION...
MODERATE TO BREEZY TRADE WINDS WILL CONTINUE THROUGH THE PERIOD.
AREAS OF LOCALIZED LIGHT LOW LEVEL TURB CAN BE EXPECTED IN SELECT
AREAS LEE OF THE TERRAIN. HOWEVER...WIDESPREAD LOW LEVEL TURB IS NOT
EXPECTED TONIGHT. THIS WILL BE REEVALUATED FRIDAY MORNING AND THE
POSSIBILITY OF AIRMET TANGO MAY ARISE.

OTHERWISE CLOUDS AND SHOWERS WILL FOCUS ALONG WINDWARD AND MOUNTAIN
AREAS. EXPECT MAINLY VFR WITH ONLY MVFR IN BRIEF PASSING SHOWERS.

&&

.MARINE...
A SMALL CRAFT ADVISORY CONTINUES FOR THE TYPICALLY WINDIER AREAS
NEAR MAUI AND THE BIG ISLAND. AS THE REMNANT LOW THAT WAS FORMER
DEPRESSION EIGHT-E PASSES SOUTH OF THE STATE...IT MAY STRENGTHEN THE
GRADIENT ENOUGH TO WARRANT EXPANSION OF THE ADVISORY TO ADDITIONAL
CHANNELS NEAR KAUAI AND OAHU.

NO MAJOR SWELLS ARE EXPECTED FOR THE NEXT SEVERAL DAYS. SURF IS
EXPECTED TO REMAIN BELOW THE ADVISORY THRESHOLD ALONG ALL SHORES.

THE NATIONAL HURRICANE CENTER IN MIAMI IS ISSUING BULLETINS ON
TROPICAL STORM GUILLERMO...WHICH IS NEARLY 2000 MILES EAST-SOUTHEAST
OF HILO. THE CURRENT FORECAST IS FOR GUILLERMO TO MOVE
WEST-NORTHWEST AND STRENGTHEN...POTENTIALLY CROSSING 140W INTO THE
CENTRAL PACIFIC HURRICANE CENTER AREA OF RESPONSIBILITY ON SATURDAY.
IMPACTS TO HAWAII WILL BE VERY DEPENDENT UPON THE TRACK AND SPEED OF
THE SYSTEM...WHICH IS HIGHLY UNCERTAIN THIS FAR OUT IN TIME.

&&

.HFO WATCHES/WARNINGS/ADVISORIES...
SMALL CRAFT ADVISORY UNTIL 6 AM HST SUNDAY FOR THE PAILOLO AND
ALENUIHAHA CHANNELS...MAALAEA BAY...AND WATERS SOUTH OF THE BIG
ISLAND.

&&

$$

DISCUSSION/MARINE...BRAVENDER
AVIATION...EATON




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