836
FXHW60 PHFO 070915
AFDHFO
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HONOLULU HI
1115 PM HST SUN SEP 6 2026
SYNOPSIS
BREEZY EASTERLY TRADE WINDS WILL CONTINUE TO GRADUALLY VEER TO THE
EAST-SOUTHEAST OVER THE NEXT DAY OR SO AS HURRICANE LOWELL
APPROACHES THE WESTERN ISLANDS FROM THE SOUTH. LOWELL IS FORECAST
TO PASS WEST OF KAUAI'S COASTAL WATERS MONDAY NIGHT. A HURRICANE
WARNING HAS BEEN ISSUED FOR KAUAI AND NIIHAU. IMPACTS SUCH AS
HIGH SURF AND HEAVY RAIN COULD IMPACT ALL OF THE ISLANDS.
DISCUSSION
HURRICANE LOWELL IS ABOUT 450 MILES SOUTH-SOUTHWEST OF KAUAI THIS
EVENING AND MOVING NORTHWARD. LOWELL IS EXPECTED TO PASS WEST OF
THE KAUAI COASTAL WATERS LATE MONDAY THROUGH MONDAY NIGHT.
LOWELL'S TRACK HAS NUDGED TO THE EAST, IT HAS RAISED THE
POSSIBILITY OF HURRICANE FORCE WINDS REACHING KAUAI AND NIIHAU, AS
A RESULT A HURRICANE WARNING HAS ALSO BEEN ISSUED FOR BOTH
ISLANDS.
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.
THE FLOOD WATCH FOR THE STATE CONTINUES THROUGH TUESDAY AFTERNOON.
MOSTURE AHEAD OF LOWELL IS BEGINNING TO LIFT UP FROM SOUTH OF THE
STATE INTERACTING WITH TERRIAN AND THE TRADE WINDS RESULTING IN
SOME WARNINGS AND ADVISORIES ALREADY. HAVE ADJUSTED QPF UPWARD
ESPECIALLY ACROSS THE CENTRAL PART OF THE STATE WHERE VALUES WERE
A BIT LOWER, SO LOOKING AT 4 TO 6 INCHES OVER MOST OF THE STATE
WITH HIGHER VALUES OVER KAUAI AND SOUTHEAST BIG ISLAND. 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.
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. THESE 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.
FOR SURF AND OTHER MARINE IMPACTS, PLEASE SEE THE MARINE SECTION
OF THE DISCUSSION BELOW.
ANY DEVIATION IN TRACK OR INTENSITY COULD ALSO CHANGE HOW THESE
HAZARDS EFFECT THE ISLANDS.
HIGH PRESSURE IS FORECAST TO BUILD BACK IN THURSDAY THROUGH
SATURDAY, BRINGING IN A MORE TYPICAL TRADE WIND PATTERN WITH A
DRIER AND MORE STABLE AIRMASS.
AVIATION
HURRICANE LOWELL CONTINUES ITS TRACK NORTHWARD, ADVECTING UNSTABLE
DEEP TROPICAL MOISTURE NORTHWARD INTO THE ISLANDS. SHOWER
ACTIVITY WILL CONTINUE TO TREND HIGHER OVER THE NEXT 24 HOURS.
MVFR CONDITIONS WITH LOW CLOUD CEILINGS AND SHOWERS ARE EXPECTED.
HEAVIER SHOWERS WILL PRODUCE PERIODS OF IFR CONDITIONS. SURFACE
WINDS WILL STRENGTHEN TODAY OVER THE WESTERN HALF OF THE STATE, AS
HURRICANE LOWELL CONTINUES ON A NORTHERN TRACK.
AIRMET SIERRA FOR MOUNTAIN OBSCURATION CONTINUES FOR KAUAI OAHU
MOLOKAI MAUI AND THE BIG ISLAND. THIS AIRMET WILL LIKELY CONTINUE
FOR THE NEXT 24 HOURS.
AIRMET TANGO WAS ISSUED FOR MODERATE LOW LEVEL TURBULENCE
AFFECTING THE ISLAND OF KAUAI OVER AND SW THRU NW OF ISLAND
MOUNTAINS. A STRONG SURFACE WIND AIRMET WILL LIKELY BE ISSUED FOR
KAUAI AND NIIHAU ON MONDAY FOR WIND SPEEDS GREATER THAN 30 KNOTS
DUE TO HURRICANE LOWELL APPROACHING THE ISLANDS.
LIGHT ICING CONTINUES IN A LAYER BETWEEN 160 AND FL220 DUE TO
STRENGTHENING LOW LEVEL WIND SPEEDS AS LOWELL APPROACHES THE
ISLAND.
MARINE
HURRICANE LOWELL LOCATED SOUTHWEST OF THE ISLANDS CONTINUES TO
MOVE NORTH-NORTHEAST THIS EVENING. AS IT APPROACHES THE ISLAND
CHAIN WIND SPEEDS WILL BEGIN TO INCREASE. A HURRICANE WARNING IS
NOW IN EFFECT FOR WATERS WEST OF KAUAI COUNTY, WHILE A TROPICAL
STORM WARNING REMAINS IN EFFECT FOR KAUAI CHANNEL AND KAUAI
WINDWARD WATERS THROUGH TUESDAY AFTERNOON. THE SMALL CRAFT
ADVISORY REMAINS IN EFFECT FOR ALL REMAINING COASTAL WATERS FOR A
COMBINATION OF WINDS AND SEAS THROUGH MONDAY NIGHT. WINDS ARE
EXPECTED TO INCREASINGLY VEER TO THE SOUTHEAST TO SOUTH AS LOWELL
CONTINUES TO APPROACH AND BRING THE STRONGEST WINDS TO THE WESTERN
END OF THE STATE.
HURRICANE CONDITIONS ARE EXPECTED IN THE WESTERN OFFSHORE WATERS
TONIGHT THROUGH TUESDAY AS THE CENTER OF THE STORM IS EXPECTED TO
TRACK JUST WEST OF NIIHAU. ANY SLIGHT DEVIATION IN THE TRACK TO
THE WEST OR EAST IN THE NEXT 24 HOURS WILL HAVE SIGNIFICANT
DIFFERENCES IN IMPACT FOR THE COASTAL WATERS AROUND KAUAI COUNTY.
POST-TROPICAL CYCLONE KARINA TO THE NORTHEAST OF THE ISLANDS WILL
CONTINUE TO WEAKEN AND DISSIPATE BY MONDAY.
THE HIGH SURF ADVISORY (HSA) HAS BEEN UPGRADED TO A HIGH SURF
WARNING (HSW) FOR ALL SOUTH FACING SHORES THROUGH MONDAY NIGHT.
SURF WILL CONTINUE TO TREND IN THE HSA RANGE THROUGH TONIGHT
BEFORE THE SOUTH SWELL FROM HURRICANE LOWELL IS EXPECTED TO RISE
RAPIDLY MONDAY, AND PEAK MONDAY NIGHT BRINGING WARNING LEVEL SURF
TO EXPOSED SHORELINES. THIS SWELL MAY SHIFT OUT OF THE SOUTHWEST
LATE MONDAY NIGHT. DUE TO THE TRACK OF LOWELL, A SHARP GRADIENT IN
SWELL IS EXPECTED FROM WEST TO EAST. COINCIDING ALSO WITH THE PEAK
MONTHLY AFTERNOON HIGH TIDES, THIS COULD BRING THE POTENTIAL FOR
SIGNIFICANT DAMAGE TO COASTAL PROPERTIES AND INFRASTRUCTURE,
INCLUDING ROADWAYS TO PORTIONS OF KAUAI AND POSSIBLY OAHU. SWELL
ENERGY IS EXPECTED TO DROP OFF QUICKLY ON TUESDAY.
A LARGE, MEDIUM-PERIOD EAST SWELL FROM FORMER TROPICAL STORM
KARINA WILL ALSO CONTINUE TO PRODUCE HSA LEVEL SURF ALONG EAST
FACING SHORES THROUGH MONDAY NIGHT. SURF ALONG NORTH FACING SHORES
WILL REMAIN FLAT EXCEPT AREAS EXPOSED TO THE STORM SWELLS. A
SMALL MEDIUM PERIOD NORTHWEST SWELL IS EXPECTED ON TUESDAY AS
LOWELL BEGINS TO LIFT NORTHWEST OF THE ISLANDS AND WILL FADE
THROUGH THURSDAY. BY THE END OF THE WEEK, SURF ALONG EAST FACING
SHORES COULD BE BOLSTERED BY SOME MEDIUM-PERIOD SWELL GENERATED
BY TROPICAL STORM MARIE IN THE EAST PACIFIC. OTHERWISE, EXPECT
CHOPPY CONDITIONS FROM EASTERLY TRADE WIND SWELL 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
MONDAY DUE TO THE UNSTABLE AIRMASS MOVING OVERHEAD. TEMPERATURE
INVERSION HEIGHTS ARE CURRENTLY NEAR 11,000 FT FROM MAUI TO THE
BIG ISLAND, AND ARE EXPECTED TO REMAIN ELEVATED DURING THE NEXT
FEW DAYS.
HYDROLOGY
THE POTENTIAL FOR FLOODING EXISTS THROUGH TUESDAY AFTERNOON, AND
AS A RESULT, A FLOOD WATCH IS IN EFFECT FOR THE ENTIRE STATE.
BETWEEN NOW AND TUESDAY AFTERNOON, HURRICANE LOWELL IS EXPECTED
TO BRING ADDITIONAL RAIN TO THE ISLANDS WITH 6 TO 10 INCHES FOR
KAUAI, WITH MAXIMUM TOTALS OF 16 INCHES POSSIBLE. FOR THE BIG
ISLAND, 4 TO 8 INCHES OF RAIN IS EXPECTED WITH ISOLATED TOTALS OF
12 INCHES, DUE TO THE TERRAIN INFLUENCE WITH THE SOUTHEAST FLOW.
ACROSS THE REMAINING ISLANDS, RAINFALL OF 4 TO 7 INCHES OF RAIN
IS EXPECTED, WITH MAUI HAVING ISOLATED MAXIMUM TOTALS OF 9 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 TUESDAY AFTERNOON FOR ALL HAWAII ISLANDS-
HIGH SURF WARNING UNTIL 6 AM HST TUESDAY FOR NIIHAU-KAUAI
LEEWARD-WAIANAE COAST-KAHOOLAWE-MAUI LEEWARD WEST-KONA-KOHALA-
KAUAI EAST-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.
HIGH SURF ADVISORY UNTIL 6 AM HST TUESDAY FOR OLOMANA-KOOLAU
WINDWARD-MOLOKAI WINDWARD-WINDWARD HALEAKALA-BIG ISLAND EAST-BIG
ISLAND NORTH.
HURRICANE WARNING FOR NIIHAU-KAUAI-
HURRICANE WARNING FOR KAUAI NORTHWEST WATERS-KAUAI LEEWARD
WATERS.
TROPICAL STORM WARNING FOR KAUAI WINDWARD WATERS-KAUAI CHANNEL.
SMALL CRAFT ADVISORY UNTIL 6 AM HST TUESDAY FOR OAHU WINDWARD
WATERS-OAHU LEEWARD WATERS-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...FOSTER
AVIATION...BOHLIN
MARINE...QUESADA
FIRE WEATHER...FOSTER
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