001
FXHW60 PHFO 080906
AFDHFO
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HONOLULU HI
1106 PM HST MON SEP 7 2026
SYNOPSIS
SOUTHEAST TO SOUTH WINDS WILL REMAIN STRONG TONIGHT AS HURRICANE
LOWELL MAKES ITS CLOSEST APPROACH TO NI'IHAU AND KAUAI. THE CORE
OF LOWELL CONTINUE MOVING NORTHWARD BY TUESDAY MORNING, AWAY FROM
THE ISLANDS. DAMAGING HURRICANE CONDITIONS ARE WILL CONTINUE ON
KAUAI WITH NUMEROUS THREATS IN PLACE THROUGHOUT THE STATE. A
HURRICANE WARNING IS IN EFFECT FOR KAUAI AND NIIHAU AND A TROPICAL
STORM WARNING IS IN EFFECT FOR OAHU. HIGH SURF AND HEAVY RAIN
WILL IMPACT ALL ISLANDS WITH STRONG WINDS MAINLY IMPACTING THE
WESTERN END OF THE STATE. WINDS WILL EASE LATER IN THE DAY ON
TUESDAY.
DISCUSSION
AT 11 PM HST, HURRICANE LOWELL WAS ABOUT 90 MILES WEST OF LIHUE
OR 190 MILES WEST NORTHWEST OF HONOLULU MOVING NORTH
NORTHEASTWARD AT 18 MPH AS A HIGH END CATEGORY 2 (MAXIMUM
SUSTAINED WINDS OF 110 MPH). IR SATELLITE IMAGERY SHOWS AN
OBSCURED EYE AS A MID AND UPPER LEVEL CLOUD SHIELD DOMINATES OVER
THE CENTER. TROPICAL STORM FORCE WINDS ARE WIDESPREAD ACROSS
KAUAI. SEVERAL STATIONS ON THE LEEWARD SIDE OF THE ISLAND,
BETWEEN WAIMEA AND BARKING SANDS, HAVE ALREADY GUSTED TO ABOVE
HURRICANE FORCE. ON OAHU, WINDS CONTINUE TO INCREASE AS WELL WITH
MANY STATIONS, MAINLY CONCENTRATED OVER THE WAIANAE MOUNTAIN
RANGE AND DOWNSLOPE OF ITS TERRAIN, REPORTING GUSTS TO TROPICAL
STORM FORCE. THE CORE OF LOWELL IS WILL MAKE ITS CLOSEST APPROACH
TO NI'IHAU AND KAUAI IN THE NEXT COUPLE OF HOURS, BEFORE
DEPARTING NORTHWARD AND AWAY FROM THE STATE.
ADDITIONAL IMPACTS FROM LOWELL ARE EXPECTED STATEWIDE, AND A FEW
HEADLINES ARE IN EFFECT AS A RESULT. A HIGH SURF WARNING FOR SOUTH
FACING SHORES FOR THE SOUTH SWELL GENERATED BY LOWELL FOR ALL
ISLANDS, ALONG WITH THE WEST FACING SHORES OF THE BIG ISLAND. 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.
THE FLOOD WATCH FOR THE STATE CONTINUES THROUGH TUESDAY DUE TO
HEAVY RAIN BROUGHT IN BY LOWELL AND ASSOCIATED RAIN AND
THUNDERSTORM BANDS. TERRAIN INFLUENCE WILL PLAY A BIG FACTOR WITH
ISOLATED AREAS RECEIVING SIGNIFICANT AMOUNTS THROUGH THE EVENT.
STAY ALERT FOR THE ISSUANCE OF ANY FUTURE FLOOD ADVISORIES OR
WARNINGS ACROSS THE STATE. SEE HYDROLOGY SECTION FOR ADDITIONAL
INFORMATION.
THE THREAT OF SHORT-LIVED, FAST-MOVING TORNADOS/WATERSPOUTS WILL
BE PRESENT MAINLY NEAR KAUAI AND NIIHAU AS LOWELL MAKES ITS
CLOSEST APPROACH TO THE ISLANDS THROUGH EARLY TUESDAY MORNING. A
TORNADO WATCH IS IN EFFECT FOR KAUAI AND NIIHAU. ANY TORNADOES
WOULD LIKELY BE EMBEDDED IN RAINBANDS. THE THREAT FOR TORNADOES IS
LOWER NEAR THE REMAINING ISLANDS, BUT NOT ZERO. THE THREAT FOR
TORNADOES SHOULD DECREASE QUICKLY EARLY TUESDAY MORNING.
HIGH PRESSURE IS FORECAST TO BUILD BACK IN THURSDAY THROUGH
SATURDAY, BRINGING IN A MORE TYPICAL TRADE WIND PATTERN. MOISTURE
MAY TAKE A BIT LONGER TO EXIT THE AREA AS WELL, SO CONDITIONS ARE
EXPECTED TO DRY OUT MORE GRADUALLY INTO THE WEEKEND.
AVIATION
HURRICANE LOWELL CONTINUES ITS TRACK NORTHWARD, PASSING JUST WEST
OF NIIHAU AND KAUAI THIS EVENING. 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.
PERIODS OF MVFR CONDITIONS WITH LOW CLOUD CEILINGS AND SHOWERS
WILL LINGER ACROSS THE STATE INTO TUESDAY. HEAVIER SHOWERS WILL
PRODUCE BRIEF PERIODS OF IFR CONDITIONS. SHOWER ACTIVITY WILL
GRADUALLY DECREASE THROUGH TUESDAY. SURFACE WINDS WILL ALSO STEADILY
DECREASE THROUGH THE MORNING HOURS AS LOWELL MOVES NORTHWARD.
AIRMET SIERRA FOR IFR CONDITIONS CONTINUE FOR KAUAI AND OAHU.
ELSEWHERE MOUNTAIN OBSCURATIONS REMAIN IN EFFECT FOR MOLOKAI MAUI
AND THE BIG ISLAND. LOW MVFR CLOUD CEILINGS WILL GRADUALLY
DIMINISH IN COVERAGE THROUGH THE TUESDAY MORNING HOURS.
AIRMET TANGO REMAINS IN EFFECT FOR MODERATE LOW LEVEL TURBULENCE
AFFECTING THE ISLAND OF KAUAI AND OAHU OVER AND SW THRU NW OF
ISLAND MOUNTAINS. A STRONG SURFACE WIND AIRMET WAS ISSUED FOR
KAUAI AND OAHU FOR WIND SPEEDS GREATER THAN 30 KNOTS DUE TO
HURRICANE LOWELL APPROACHING THE ISLANDS. THESE AIRMETS WILL
LIKELY BE CANCELLED BY LATE TUESDAY MORNING.
LIGHT ICING CONTINUES IN A LAYER BETWEEN 160 AND FL220.
MARINE
HURRICANE LOWELL IS ON TRACK TO PASS WEST OF NIIHAU OVER THE
COMING HOURS. WINDS AND SEAS ARE ON THE INCREASE AS THE SYSTEM
APPROACHES, AND BOTH ARE EXPECTED TO PEAK OVERNIGHT AS LOWELL
MAKES IT CLOSEST APPROACH TO KAUAI COUNTY. 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 REMAINS IN EFFECT FOR ALL REMAINING COASTAL
WATERS FOR A COMBINATION OF WINDS AND SEAS THROUGH TUESDAY. WINDS
ARE EXPECTED TO INCREASINGLY VEER TO THE SOUTHEAST AND EVENTUALLY
SOUTH TONIGHT AS LOWELL APPROACHES AND BEGINS TO LIFT NORTH OF THE
ISLAND CHAIN BY TUESDAY MORNING. THE STRONGEST WINDS AND HIGHEST
SEAS ARE EXPECTED FOR THE WESTERN END OF THE STATE.
HURRICANE CONDITIONS ARE EXPECTED IN THE WESTERN OFFSHORE WATERS
THROUGH TUESDAY AS THE CENTER OF LOWELL TRACKS JUST WEST OF
NIIHAU. WHAT REMAINS OF FORMER TROPICAL CYCLONE KARINA REMAINS TO
THE NORTHEAST OF THE ISLANDS AND IS EXPECTED TO DISSIPATE SOON.
SOUTH-SOUTHWEST SWELL FROM HURRICANE LOWELL WILL CONTINUE TO BUILD
RAPIDLY AND PEAK TONIGHT AS IT SHIFTS OUT OF THE SOUTHWEST. AS A
RESULT, WARNING LEVEL SURF ALONG SOUTH FACING SHORES WILL CONTINUE
TO RISE, PEAKING OVERNIGHT. DUE TO THE TRACK OF LOWELL WEST OF
THE MAIN ISLANDS, A SHARP GRADIENT IN SWELL IS EXPECTED FROM WEST
TO EAST. THIS WILL BRING DAMAGING SURF TO PORTIONS OF KAUAI COUNTY
AND LIKELY OAHU, WITH THE POTENTIAL FOR SIGNIFICANT DAMAGE TO
COASTAL PROPERTIES AND INFRASTRUCTURE, PARTICULARLY TO THOSE AREAS
ALONG THE COASTS OF KAUAI AND OAHU EXPOSED TO THE SOUTHERLY
SWELL. THE HURRICANE SWELL ENERGY IS EXPECTED TO RAPIDLY DECLINE
ON TUESDAY AS LOWELL MOVES AWAY FROM THE ISLANDS.
A MODERATE, LONG-PERIOD SOUTH SWELL WILL PEAK OVERNIGHT AND INTO
TUESDAY, BUT WILL BE OVERWHELMED BY THE LARGER SWELL MENTIONED
ABOVE FROM HURRICANE LOWELL. THIS SWELL WILL ALSO FADE SOME ON
TUESDAY BUT WILL KEEP SOUTH SHORE SURF SOMEWHAT ELEVATED THROUGH
THURSDAY. A LARGE, MEDIUM-PERIOD EAST SWELL FROM FORMER TROPICAL
STORM KARINA WILL COMBINE WITH INCREASING EAST TO SOUTHEAST WIND
WAVE GENERATED BY HURRICANE LOWELL TO KEEP ADVISORY LEVEL SURF
ALONG EAST FACING SHORES THROUGH TUESDAY. SURF ALONG NORTH FACING
SHORES WILL ALSO EXPERIENCE A SMALL INCREASE ON TUESDAY AS LOWELL
LIFTS NORTH OF THE ISLAND CHAIN AND THEN FADE THROUGH THE WEEK.
FIRE WEATHER
FIRE WEATHER RISK WILL REMAIN LOW THROUGH THE FORECAST PERIOD DUE
TO INCREASING MOISTURE MOVING OVER THE ISLANDS IN ASSOCIATION
WITH HURRICANE LOWELL. THUNDERSTORMS WILL BE POSSIBLE THROUGH
THROUGH TONIGHT TO THE UNSTABLE AIRMASS MOVING OVERHEAD.
TEMPERATURE INVERSION HEIGHTS ARE EXPECTED TO REMAIN ELEVATED OR
NON-EXISTENT DURING THE NEXT FEW DAYS.
HYDROLOGY
OVER THE PAST 48 HOURS, GENERALLY 3 TO 10 INCHES OF RAIN HAS FALLEN
ON KAUAI WITH SLIGHTLY OVER 17 INCHES REPORTED AT THE MOUNT
WAIALEALE RAIN GAUGE. GENERALLY 1 TO 3 INCHES OF RAIN HAS FALLEN
OVER OAHU WITH 5 TO 9 INCHES ACCUMULATING OVER THE KOOLAU RANGE.
5 TO 10 INCHES OF RAIN HAVE FALLEN ALONG THE WINDS SLOPES OF MAUI
WITH MUCH LESS REPORTED IN THE LOWER ELEVATIONS OF MAUI, LANAI, AND
MOLOKAI. 3 TO 5 INCHES OF RAIN HAS FALLEN ALONG WINDWARD AND
SOUTHEASTERN FACING BIG ISLAND WITH LESS THAN AN INCHES FOR LEEWARD
SIDES. THE POTENTIAL FOR FLOODING REMAINS THROUGH LATE TUESDAY, AND
A FLOOD WATCH REMAINS IN EFFECT FOR THE ENTIRE STATE. DUE TO THE
AMOUNT OF RAIN THAT HAS FALLEN, ESPECIALLY OVER KAUAI TODAY, ANY
HEAVY SHOWERS COULD TRIGGER QUICK FLASH FLOODING. THE WATCH MAY NEED
TO BE EXTENDED THROUGH MIDWEEK AS LINGERING MOISTURE WILL REMAIN IN
PLACE IN THE WAKE OF LOWELL.
HURRICANE LOWELL IS EXPECTED TO BRING ADDITIONAL RAIN TO THE ISLANDS
THROUGH WEDNESDAY AFTERNOON WITH 3 TO 5 INCHES ACROSS KAUAI. OAHU
AND MAUI COUNTY, 1 TO 3 INCHES. BIG ISLAND, 3 TO 5 INCHES. THIS
RAINFALL MAY PRODUCE SIGNIFICANT FLASH FLOODING AND MUDSLIDES,
ESPECIALLY ACROSS KAUAI COUNTY, OAHU, AND POTENTIALLY EAST PORTIONS
OF THE BIG ISLAND. ITS IMPORTANT TO NOTE THAT ANY POP UP
THUNDERSTORMS THAT DEVELOP COULD DRAMATICALLY INCREASE TOTAL
RAINFALL AMOUNTS ANYWHERE.
HFO WATCHES/WARNINGS/ADVISORIES
FLOOD WATCH THROUGH TUESDAY AFTERNOON FOR ALL HAWAII ISLANDS-
HIGH SURF WARNING UNTIL 6 PM HST TUESDAY 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 TUESDAY 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 TUESDAY 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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