330
FXHW60 PHFO 081507
AFDHFO
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HONOLULU HI
507 AM HST TUE SEP 8 2026
SYNOPSIS
SOUTH WINDS WILL REMAIN STRONG THIS MORNING OVER KAUAI AND OAHU
AS HURRICANE LOWELL EDGES NORTH OF THE STATE. A HURRICANE WARNING
REMAINS IN EFFECT FOR KAUAI AND NIIHAU, ALONG WITH A TROPICAL
STORM WARNING FOR OAHU. HIGH SURF AND PERIODS OF HEAVY RAIN WILL
IMPACT ALL ISLANDS TO SOME EXTENT WITH STRONG WINDS MAINLY
IMPACTING THE WESTERN END OF THE STATE. WINDS WILL EASE LATE THIS
MORNING INTO THE AFTERNOON. TRAILING MOISTURE FROM LOWELL WILL
LEAD TO AN ENHANCEMENT OF SHOWER ACTIVITY OVER BIG ISLAND AND MAUI
COUNTY THROUGH THE MIDDLE OF THE WEEK.
DISCUSSION
AT 5 AM HST, HURRICANE LOWELL WAS ABOUT 145 MILES NORTHWEST OF
LIHUE OR 245 MILES NORTHWEST OF HONOLULU MOVING NORTH
AT 18 MPH AS A CATEGORY 1 (MAXIMUM SUSTAINED WINDS OF 90 MPH). IR
SATELLITE IMAGERY SHOWS MID AND UPPER LEVEL CLOUDS BEING SHEARED
OFF THE LOWER LEVEL CIRCULATION, TYPICAL OF WEAKENING TROPICAL
CYCLONE. AS LOWELL MOVES AWAY FROM THE HAWAIIAN ISLANDS THE NEXT
SEVERAL DAYS, FURTHER WEAKENING IS EXPECTED DUE TO PERSISTENT
SHEAR AND DECREASING SEA SURFACE TEMPERATURES ALONG ITS TRACK.
ACROSS KAUAI, TROPICAL STORM FORCE WINDS WERE WIDESPREAD EARLY
THIS MORNING WITH SEVERAL STATIONS GUSTING TO HURRICANE FORCE. A
HANDFUL OF STATIONS ACROSS NORTHWEST OAHU, MAINLY OVER AND IN THE
LEE OF THE WAIANAE RANGE, REPORTED TROPICAL STORM FORCE GUSTS.
SURFACE PRESSURE GRADIENTS SHOULD LOOSEN AS THE DAY PROGRESSES
WITH SOUTHERLY WINDS GRADUALLY EASING.
ADDITIONAL IMPACTS FROM LOWELL ARE EXPECTED TO CONTINUE STATEWIDE,
AT LEAST THROUGH THIS AFTERNOON, AND SEVERAL HEADLINES ARE IN
EFFECT AS A RESULT. A HIGH SURF WARNING REMAINS IN EFFECT FOR
SOUTH FACING SHORES FOR ALL ISLANDS, ALONG WITH THE WEST FACING
SHORES OF THE BIG ISLAND, THOUGH SURF AND SWELL SHOULD DECLINE
THROUGH THE DAY. A HIGH SURF ADVISORY REMAINS IN EFFECT FOR THE
EAST SWELL GENERATED BY FORMER TROPICAL STORM KARINA, WHICH HAS
WEAKENED TO A POST TROPICAL LOW. FOR SURF AND OTHER MARINE
IMPACTS, PLEASE SEE THE MARINE SECTION OF THE DISCUSSION BELOW.
A FLOOD WATCH REMAINS IN EFFECT FOR THE ENTIRE STATE THROUGH THIS
AFTERNOON AS LOWELL BRINGS DEEP MOIST SOUTHERLY FLOW ACROSS THE
ISLANDS. MID TO LATE WEEK, BOTH THE GFS AND ECMWF SHOW THE
TRAILING BAND OF DEEP MOISTURE LINGERING OVER THE EASTERN HALF OF
THE STATE. CONFIDENCE IS INCREASING THAT THE FLOOD WATCH WILL
NEED TO BE EXTENDED FOR BIG ISLAND AND POSSIBLY MAUI COUNTY TO
COVER ANY ADDITIONAL ENHANCEMENT OF SHOWER ACTIVITY. DIURNAL
HEATING, COMBINED WITH A RELATIVELY DEEP MOISTURE LAYER WILL ALSO
ALLOW FOR A SLIGHT CHANCE OF THUNDERSTORMS OVER INTERIOR BIG
ISLAND BOTH THIS AFTERNOON AND WEDNESDAY AFTERNOON. SEE HYDROLOGY
SECTION FOR ADDITIONAL INFORMATION.
THE TORNADO WATCH HAS BEEN CANCELLED FOR KAUAI COUNTY AND ITS
SURROUNDING WATERS. THE CENTER OF HURRICANE LOWELL HAS NOW MOVED
NORTH OF THE STATE AND THE AFOREMENTIONED AREA IS NO LONGER IN
THE TORNADIC PRONE FRONT RIGHT QUADRANT OF THE STORM.
HIGH PRESSURE IS FORECAST TO BUILD BACK IN LATE THURSDAY THROUGH
SATURDAY, BRINGING BACK A WEAK TRADE WIND PATTERN. MOISTURE MAY
STILL TAKE A BIT LONGER TO EXIT THE AREA, SO EXPECT SOME
ENHANCEMENT TO SHOWER ACTIVITY TO PERSIST.
AVIATION
HURRICANE LOWELL CONTINUES ITS TRACK NORTHWARD, PASSING JUST WEST
OF NIIHAU AND KAUAI. DEEP UNSTABLE TROPICAL MOISTURE CONTINUES TO
STREAM NORTHWARD ACROSS ALL ISLANDS. SHOWER ACTIVITY WILL LINGER
EVEN AFTER LOWELL BEGINS TO MOVE FARTHER NORTHWARD AWAY FROM THE
HAWAIIAN ISLANDS TODAY.
PERIODS OF MVFR CONDITIONS WITH LOW CLOUD CEILINGS AND SHOWERS
WILL LINGER ACROSS THE STATE. MVFR SHOWER ACTIVITY WILL GRADUALLY
DECREASE THROUGH THE MORNING HOURS. SURFACE WINDS WILL ALSO
STEADILY DECREASE TODAY.
AIRMET SIERRA FOR LOW MVFR CLOUD CEILINGS REMAINS IN EFFECT AND WILL
GRADUALLY DIMINISH IN COVERAGE THROUGH THE MORNING HOURS.
AIRMET TANGO REMAINS IN EFFECT FOR MODERATE LOW LEVEL TURBULENCE
AFFECTING THE ISLAND OF KAUAI AND OAHU OVER AND NW THRU NE OF
ISLAND MOUNTAINS. A STRONG SURFACE WIND AIRMET REMAINS IN EFFECT
FOR KAUAI AND OAHU FOR WIND SPEEDS GREATER THAN 30 KNOTS DUE TO
HURRICANE LOWELL. THESE AIRMETS WILL LIKELY BE CANCELLED LATER
THIS MORNING.
MARINE
HURRICANE LOWELL IS NOW LIFTING NORTH OF KAUAI AND NIIHAU. A
HURRICANE WARNING REMAINS IN EFFECT FOR WATERS WEST OF KAUAI
COUNTY, WHILE A TROPICAL STORM WARNING REMAINS IN EFFECT FOR KAUAI
CHANNEL, KAUAI WINDWARD WATERS, OAHU WINDWARD WATERS AND OAHU
LEEWARD WATERS. THE SMALL CRAFT ADVISORY (SCA) ALSO REMAINS IN
EFFECT FOR ALL REMAINING COASTAL WATERS FOR A COMBINATION OF WINDS
AND SEAS. WINDS AND SEAS ARE EXPECTED TO DECREASE RAPIDLY TODAY
AS THE HURRICANE WEAKENS AND MOVES AWAY FROM THE ISLANDS, FALLING
BELOW SCA CRITERIA BY THIS EVENING. FOR THE WESTERN OFFSHORE
WATERS, HURRICANE CONDITIONS ARE EXPECTED TO CONTINUE TODAY UNTIL
THE CYCLONE EXITS THE REGION TO THE NORTHWEST.
SOUTHWEST SWELL FROM HURRICANE LOWELL PRODUCED SURF ALONG SOUTH
FACING SHORES IN EXCESS OF WARNING CRITERIA OVERNIGHT. THIS SURF
CONTINUES INTO THE EARLY MORNING HOURS, WHICH MAY CONTINUE TO
BRING DAMAGING SURF TO PORTIONS OF KAUAI COUNTY WITH THE
POTENTIAL FOR SIGNIFICANT DAMAGE TO COASTAL PROPERTIES AND
INFRASTRUCTURE, PARTICULARLY TO THOSE AREAS ALONG THE COAST
EXPOSED TO THE SOUTHERLY SWELL OVER THE NEXT SEVERAL HOURS. SURF
WILL QUICKLY FALL TO ADVISORY CRITERIA AND THEN BELOW ADVISORY
CRITERIA BY TONIGHT. AN ADDITIONAL MODERATE, LONG-PERIOD SOUTH
SWELL WHICH IS PEAKING TODAY WILL THEN KEEP SURF ELEVATED JUST
BELOW ADVISORY CRITERIA ONCE THE SOUTHWEST SWELL FROM LOWELL FADES
BY THIS AFTERNOON. THIS SOUTHERLY SWELL WILL MAINTAIN SOME SOUTH
SHORE SURF AS IT GRADUALLY FADES THROUGH THURSDAY.
A MEDIUM-PERIOD EAST SWELL FROM FORMER TROPICAL STORM KARINA COMBINED
WITH EAST TO SOUTHEAST WIND WAVE GENERATED BY HURRICANE LOWELL WILL
MAINTAIN ADVISORY LEVEL SURF ALONG EAST FACING SHORES THIS MORNING,
BUT WILL DROP BELOW ADVISORY LEVELS BY TONIGHT. SURF ALONG NORTH
FACING SHORES WILL EXPERIENCE A SMALL BUMP ON TUESDAY WITH LOWELL
LOCATED NORTHWEST OF THE ISLAND CHAIN AND THEN FADE THROUGH THE WEEK
AS IT WEAKENS AND TRACKS AWAY FROM THE ISLANDS.
FIRE WEATHER
FIRE WEATHER RISK WILL REMAIN LOW THE NEXT SEVERAL DAYS DUE
RESIDUAL MOISTURE ASSOCIATED WITH HURRICANE LOWELL. EXPECT A
SLIGHT CHANCE OF THUNDERSTORMS OVER THE BIG ISLAND ON WEDNESDAY
AFTERNOON AND THURSDAY AFTERNOON. TEMPERATURE INVERSION HEIGHTS
ARE EXPECTED TO REMAIN ELEVATED OR WEAK.
HYDROLOGY
HURRICANE LOWELL IS EXPECTED TO PRODUCE ADDITIONAL RAINFALL
TOTALS OF 2 TO 4 INCHES FOR KAUAI, WITH MAXIMUM STORM TOTALS OF 24
INCHES POSSIBLE. FOR THE BIG ISLAND, AN ADDITIONAL 3 TO 6 INCHES
OF RAIN IS EXPECTED WITH ISOLATED STORM TOTALS OF 8 INCHES
POSSIBLE. FOR OAHU AND MAUI COUNTIES, AN ADDITIONAL 1 TO 3 INCHES
OF RAIN IS EXPECTED WITH ISOLATED STORM TOTALS OF 8 INCHES
POSSIBLE. THIS RAINFALL MAY PRODUCE SIGNIFICANT FLASH FLOODING AND
MUDSLIDES, ESPECIALLY ACROSS KAUAI COUNTY AND PORTIONS OF THE BIG
ISLAND.
HFO WATCHES/WARNINGS/ADVISORIES
FLOOD WATCH THROUGH THIS AFTERNOON FOR ALL HAWAII ISLANDS-
HIGH SURF WARNING UNTIL 6 PM HST THIS EVENING FOR NIIHAU-KAUAI
LEEWARD-WAIANAE COAST-KAHOOLAWE-MAUI LEEWARD WEST-KONA-KOHALA-
KAUAI SOUTH-EAST HONOLULU-HONOLULU METRO-EWA PLAIN-MOLOKAI
SOUTHEAST-MOLOKAI WEST-MOLOKAI LEEWARD SOUTH-LANAI LEEWARD-LANAI
SOUTH-MAUI CENTRAL VALLEY SOUTH-KIPAHULU-SOUTH MAUI/UPCOUNTRY-
SOUTH HALEAKALA-BIG ISLAND SOUTH-BIG ISLAND SOUTHEAST.
HURRICANE WARNING FOR NIIHAU-KAUAI-
TROPICAL STORM WARNING FOR OAHU-
HIGH SURF ADVISORY UNTIL 6 PM HST THIS EVENING FOR OLOMANA-KAUAI
EAST-KOOLAU WINDWARD-MOLOKAI WINDWARD-WINDWARD HALEAKALA-BIG
ISLAND EAST-BIG ISLAND NORTH.
HURRICANE WARNING FOR KAUAI NORTHWEST WATERS-KAUAI LEEWARD
WATERS.
TROPICAL STORM WARNING FOR KAUAI WINDWARD WATERS-KAUAI CHANNEL-
OAHU WINDWARD WATERS-OAHU LEEWARD WATERS.
SMALL CRAFT ADVISORY UNTIL 6 PM HST THIS EVENING FOR KAIWI
CHANNEL-MAUI COUNTY WINDWARD WATERS-MAUI COUNTY LEEWARD WATERS-
MAALAEA BAY-PAILOLO CHANNEL-ALENUIHAHA CHANNEL-BIG ISLAND
WINDWARD WATERS-BIG ISLAND LEEWARD WATERS-BIG ISLAND SOUTHEAST
WATERS.
DISCUSSION...THOMAS
AVIATION...BOHLIN
MARINE...QUESADA
FIRE WEATHER...THOMAS
HYDROLOGY...THOMAS
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