Area Forecast Discussion
Issued by NWS Honolulu, HI

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000
FXHW60 PHFO 012013
AFDHFO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HONOLULU HI
1000 AM HST SUN FEB 1 2015

.SYNOPSIS...
GENTLE TRADE WINDS OVER MOST LOCATIONS TODAY WILL TURN TO THE
SOUTHWEST AHEAD OF AN APPROACHING FRONT ON MONDAY. A SERIES OF
FRONTS WILL IMPACT THE ISLANDS THIS WEEK...BRINGING AN INCREASE IN
CLOUDS AND SHOWERS. THE BIGGER IMPACT WILL BE STRONGER WINDS THAT
WILL BE ASSOCIATED WITH THE APPROACHING SYSTEMS.

&&

.DISCUSSION...
THE BIG STORY THIS WEEK WILL BE THE WINDS THAT WILL IMPACT THE
ISLANDS. STRONG AND GUSTY WINDS TUESDAY MAY IMPACT PORTIONS OF OAHU
TUESDAY.

A WEAK HIGH PRESSURE RIDGE NORTH OF THE ISLANDS WILL MAINTAIN GENTLE
TRADES TODAY...BUT A FRONT APPROACHING FROM THE NORTHWEST WILL TURN
THE WINDS TO THE SOUTHWEST BY TOMORROW. THE MODELS ARE IN GOOD
AGREEMENT WITH MANY ASPECTS OF THE FORECAST THROUGH THE MIDDLE OF
THE WEEK...INCLUDING AN INCREASE IN WINDS AHEAD OF...AND WITH THIS
FIRST FRONT.

THE FRONTAL PASSAGE ITSELF WILL TURN THE WINDS TO THE
WEST-NORTHWEST. AT THIS TIME IT LOOKS LIKE THE NORTHEAST AND EAST
FACING SLOPES OF THE KOOLAU RANGE ON OAHU HAS THE GREATEST CHANCE OF
SEEING THE STRONGEST DOWNSLOPING FROM THESE WINDS TUESDAY AND
TUESDAY NIGHT...WITH THE POSSIBILITY OF ADVISORY LEVEL WINDS DURING
THAT TIME PERIOD...WITH STRONG WIND GUSTS BEING THE MOST LIKELY TO
CAUSE ISSUES. OTHER AREAS AT RISK TUESDAY AND TUESDAY NIGHT ARE THE
NORTHEAST AND EAST FACING SLOPES OF THE WAIANAE MOUNTAINS.

THIS INITIAL FRONT WILL INITIALLY MOVE THROUGH KAUAI AND OAHU
TUESDAY...BEFORE SLOWING SOME OVER MAUI COUNTY. ANOTHER PUSH COMES
THROUGH TUESDAY NIGHT AND WEDNESDAY TO MOVE THE FRONT DOWN THE
ISLAND CHAIN BY WEDNESDAY NIGHT.

THROUGH MOST OF THE WEEK...THE UPPER LEVELS REMAIN ZONAL...BUT BY
FRIDAY...THE MODELS SHOW A DIGGING UPPER LEVEL TROUGH NEAR THE
ISLANDS. A FRONTAL SYSTEM ASSOCIATED WITH THIS UPPER LEVEL SYSTEM
WILL MOVE DOWN THE ISLAND CHAIN FASTER THAN THE ABOVE MENTIONED
SYSTEM...AND IS CURRENTLY EXPECTED TO MOVE THROUGH FRIDAY AND FRIDAY
NIGHT.

THE FRONTAL PASSAGE TUESDAY THROUGH WEDNESDAY NIGHT WILL LIKELY
SPREAD MORE WIDESPREAD RAIN TO THE ISLANDS THAN THE FRIDAY
SYSTEM...AS THE SYSTEM SLOWS OVER MAUI COUNTY. WHILE MODERATE
RAINFALL TOTALS ARE CURRENTLY EXPECTED...SOME LOCALIZED HEAVIER
RAINFALL IS POSSIBLE.

THE SUMMITS AND INTERIOR OF THE BIG ISLAND ARE ALSO IN FOR A WINDY
WEEK. WINDS AT THE SUMMIT ARE ALREADY ELEVATED...BUT BELOW ADVISORY
LEVELS FOR THE SUMMIT. THE SUMMITS WILL LIKELY REACH ADVISORY LEVELS
MONDAY...AND ITS POSSIBLE FOR THESE STRONGER WINDS TO EXTEND DOWN
INTO THE INTERIOR OF THE BIG ISLAND BY MONDAY NIGHT. ONCE WINDS
REACH ADVISORY LEVELS...THEY ARE EXPECTED TO REMAIN ELEVATED THROUGH
THE END OF THE WEEK. THE SUMMITS IN PARTICULAR ARE LIKELY TO REACH
WARNING LEVELS FOR SEVERAL PERIODS DURING THE SECOND HALF OF THE
WEEK.

A SURFACE RIDGE WILL MOVE OVER THE ISLANDS SATURDAY AND
SUNDAY...BRINGING A BRIEF RETURN OF LIGHTER WINDS AND DRIER
CONDITIONS. THE GLOBAL MODELS SUGGEST ANOTHER FRONT APPROACHING FROM
THE NORTHWEST MONDAY.

&&

.AVIATION...
A LINGERING AREA OF LOW-LEVEL MOISTURE NEAR MAUI COUNTY WILL
CONTINUE TO PRODUCE SHOWERS AND OCCASIONAL MVFR CONDITIONS...MAINLY
ALONG WINDWARD SECTIONS OF MAUI AND MOLOKAI. AN AIRMET FOR MOUNTAIN
OBSCURATION REMAINS IN EFFECT FOR THESE AREAS. CLOUD BASES ACROSS
EASTERN MOLOKAI IMPROVED FOR A BIT THIS MORNING...BUT ARE EXPECTED
TO LOWER AGAIN AS THE MOISTURE AXIS GRADUALLY SHIFTS WESTWARD. THE
MOUNTAIN OBSCURATION WILL LIKELY CONTINUE INTO THE AFTERNOON BEFORE
MIXING OUT ENOUGH FOR THE AIRMET TO BE DROPPED. BASED ON WEB CAMS
FROM THE HAWAIIAN VOLCANO OBSERVATORY...THE MOUNTAIN OBSCURATION FOR
SOUTHEAST BIG ISLAND ALSO REMAINS IN EFFECT.

ELSEWHERE CONDITIONS ARE PRIMARILY VFR. THE LIGHT TRADE WINDS WILL
STILL ALLOW FOR LOCALIZED ONSHORE SEA BREEZES THIS AFTERNOON...WITH
CLOUD BUILDUPS OVER INTERIOR AND NORTHEAST SECTIONS. WHILE
CONDITIONS WILL BE PREDOMINATELY VFR...BRIEF MVFR CEILINGS ARE STILL
EXPECTED IN SHOWERS DURING THE AFTERNOON.

WINDS WILL VEER TO THE SOUTHWEST BY MONDAY NIGHT AND INCREASE AHEAD
OF THE NEXT SYSTEM. THERE WILL BE THE POTENTIAL FOR MODERATE TO
LOCALLY SEVERE LOW-LEVEL TURBULENCE DOWNSTREAM OF THE TERRAIN...
WHICH IN THIS CASE WILL BE NORTH THROUGH EAST OF THE ISLANDS...
BEGINNING AS EARLY AS MONDAY NIGHT.

&&

.MARINE...
THE SWELL AT BUOY 51101 HAS BEEN ON THE DECLINE OVER THE LAST
SEVERAL HOURS...AND WE ANTICIPATE SEEING THE SWELL START TO SUBSIDE
AT THE WAIMEA BAY BUOY IN THE NEXT FEW HOURS. THE HIGH SURF ADVISORY
CONTINUES THROUGH 6 PM TODAY.

THE COMBINED SEAS FROM THE CURRENT SWELL REMAIN IN EXCESS OF 10
FT...BUT ARE EXPECTED TO DROP LATER TODAY AS WELL. THE NEXT
SIGNIFICANT SWELL IS EXPECTED TO ARRIVE WEDNESDAY NIGHT OR
THURSDAY...BUT WITH WINDS EXPECTED TO INCREASE WITH THE ABOVE
MENTIONED FRONTS...SMALL CRAFT ADVISORIES WILL LIKELY BE NEEDED DUE
TO WINDS AS EARLY AS MONDAY NIGHT.

&&

.HFO WATCHES/WARNINGS/ADVISORIES...
HIGH SURF ADVISORY UNTIL 6 PM HST THIS EVENING FOR NORTH AND WEST
FACING SHORES OF NIIHAU AND KAUAI...AND FOR NORTH FACING SHORES OF
OAHU MOLOKAI AND MAUI.

SMALL CRAFT ADVISORY UNTIL 6 PM HST THIS EVENING FOR THE WATERS
SURROUNDING KAUAI...THE OAHU WINDWARD WATERS...THE KAIWI CHANNEL AND
THE MAUI COUNTY WINDWARD WATERS.

&&

$$

DISCUSSION/MARINE...M BALLARD
AVIATION...BRAVENDER





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