033
FXHW60 PHFO 111337
AFDHFO
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HONOLULU HI
337 AM HST WED MAR 11 2026
SYNOPSIS
A POWERFUL AND SLOW-MOVING KONA LOW NORTHWEST OF THE ISLANDS WILL
BRING A PROLONGED PERIOD OF HAZARDOUS WEATHER TO THE STATE THROUGH
THE UPCOMING WEEKEND. EXPECT PERIODS OF HEAVY RAIN, BRINGING THE
POTENTIAL FOR FLASH FLOODING, STRONG KONA WINDS, AND STRONG TO
SEVERE THUNDERSTORMS.
DISCUSSION
A HIGH-IMPACT WEATHER EVENT CONTINUES TO UNFOLD ACROSS THE
HAWAIIAN ISLANDS AS A POWERFUL KONA LOW REMAINS POSITIONED
NORTHWEST OF THE STATE. RADAR IMAGERY EARLY THIS MORNING SHOWS
BANDS OF SHOWERS LIFTING NORTH ACROSS THE STATE, WITH PEAK
RAINFALL RATES RANGING BETWEEN 1 AND 2 INCHES. SEVERAL STREAMS
HAVE ALREADY BECOME ELEVATED FOLLOWING THE OVERNIGHT RAINFALL, AND
FLOODING REMAINS POSSIBLE WHERE HEAVIER SHOWERS PERSIST.
THE LARGER-SCALE PATTERN REMAINS LARGELY UNCHANGED. A BROAD
UPPER-LEVEL LOW NORTHWEST OF THE ISLANDS CONTINUES TO DEEPEN
WHILE AN ASSOCIATED UPPER TROUGH BECOMES INCREASINGLY NEGATIVELY
TILTED AS A STRONG JET STREAK, WITH CORE WINDS OF 100 TO 140 KT
NEAR 250 MB, DIGS SOUTHEASTWARD ALONG ITS WESTERN FLANK. AS THIS
TROUGH AMPLIFIES AND GRADUALLY EXPANDS TOWARD THE ISLANDS THROUGH
MIDWEEK, THE STATE WILL INCREASINGLY FALL BENEATH THE JET STREAK’S
LEFT-EXIT REGION, SUPPORTING ENHANCED DIVERGENCE ALOFT AND
LARGE-SCALE ASCENT ACROSS THE REGION.
AT THE SURFACE, A BROAD AREA OF LOW PRESSURE WILL REMAIN WELL
NORTHWEST OF THE ISLANDS IN RESPONSE TO STRONG UPPER-LEVEL HEIGHT
FALLS. CENTRAL PRESSURES ARE FORECAST TO REMAIN NEAR 990 MB WHILE
MAINTAINING A SOUTHERLY TO SOUTHEASTERLY FLOW ACROSS THE STATE.
THIS FLOW WILL CONTINUE TO TRANSPORT DEEP TROPICAL MOISTURE
NORTHWARD ACROSS THE ISLAND CHAIN, WITH PRECIPITABLE WATER VALUES
REMAINING NEAR OR ABOVE TWO INCHES.
THE COMBINATION OF STRONG UPPER-LEVEL FORCING, DEEP MOISTURE, AND
PERSISTENT SOUTHERLY FLOW WILL SUPPORT REPEATED ROUNDS OF SHOWERS
AND THUNDERSTORMS THROUGH THE REMAINDER OF THE WEEK. SMALLER
DISTURBANCES ROTATING THROUGH THE UPPER TROUGH WILL LIKELY HELP
FOCUS ADDITIONAL RAINBANDS ACROSS PORTIONS OF THE STATE, RAISING
THE POTENTIAL FOR TRAINING RAINFALL AND LOCALLY INTENSE RAINFALL
RATES, PARTICULARLY IN TERRAIN-FAVORED AREAS.
IN ADDITION TO THE RAINFALL THREAT, STRENGTHENING SOUTH TO
SOUTHWEST WINDS MAY DEVELOP FRIDAY INTO THE WEEKEND AS THE
PRESSURE GRADIENT TIGHTENS BETWEEN THE DEVELOPING LOW TO THE
NORTHWEST AND HIGH PRESSURE TO THE NORTHEAST. IF THIS
MATERIALIZES, STRONG AND POTENTIALLY DAMAGING KONA WINDS WILL BE
POSSIBLE, INCLUDING LOCALIZED DOWNSLOPE WINDS CAPABLE OF DOWNING
TREES AND POWER LINES.
ENVIRONMENTAL CONDITIONS WILL ALSO PERIODICALLY BECOME FAVORABLE
FOR STRONG TO SEVERE THUNDERSTORMS OVER THE NEXT FEW DAYS,
PARTICULARLY FRIDAY INTO SATURDAY. INSTABILITY COMBINED WITH
STRONG DEEP-LAYER WIND SHEAR DURING THIS PERIOD WILL SUPPORT
THUNDERSTORMS CAPABLE OF PRODUCING DAMAGING WINDS, LARGE HAIL, AND
POSSIBLY A TORNADO.
FOR THE SUMMITS OF THE BIG ISLAND, COLDER AIR ASSOCIATED WITH THE
UPPER TROUGH WILL PERIODS OF HEAVY SNOW WITH SIGNIFICANT
ACCUMULATIONS LATER THIS WEEK AND INTO THE WEEKEND, WHICH HAS
PROMPTED THE ISSUANCE OF A WINTER STORM WATCH THIS MORNING.
AVIATION
MODERATE TO HEAVY SHOWERS WILL PERSIST THROUGH MUCH OF THE DAY
TODAY ACROSS THE STATE WITH PROLONGED PERIODS OF MVFR CONDITIONS
WITH TEMPO IFR/LIFR CONDITIONS AT TIMES WITH THE HEAVIER SHOWERS.
INCREASING INSTABILITY TODAY SHOULD ALLOW FOR ISOLATED
THUNDERSTORMS TO DEVELOP.
AIRMET SIERRA REMAINS IN EFFECT FOR MOUNTAIN OBSCURATION FOR ALL
OF KAUAI, OAHU AND MAUI COUNTY. THE BIG ISLAND WILL NEED TO BE
ADDED TO THIS IN THE EARLY MORNING PACKAGE.
AIRMET ZULU REMAINS IN EFFECT FOR LIGHT ICING FROM KAUAI THROUGH
MAUI COUNTY.
AIRMET TANGO IS IN EFFECT FOR MODERATE TURBULENCE OVER KAUAI AND
OAHU AS THE VAD WIND PROFILE SHOWS STRONG SOUTHERLY WINDS HAVE
SPREAD ACROSS THE AREA.
AIRMET TANGO IS ALSO IN EFFECT ACROSS THE STATE FOR MODERATE
TURBULENCE ASSOCIATED WITH THE SHORT-WAVE TROUGH SWINGING THROUGH
THE STATE TODAY THIS MORNING. UPPER LEVEL TURBULENCE IS GENERALLY
EXPECTED TO DECREASE TOWARDS THE EVENING WITH THE EXCEPTION OF
AREAS WITH THUNDERSTORMS.
MARINE
A POWERFUL KONA STORM WILL RESULT IN HEAVY RAIN, THUNDERSTORMS,
AND ROUGH SEAS TO THE ISLANDS AND ADJACENT COASTAL WATERS THROUGH
THE REST OF THIS WEEK. EARLY THIS MORNING, BANDS OF HEAVY
RAINFALL ARE OBSERVED ON RADAR IMAGERY MOVING FROM SOUTH TO NORTH
WITHIN A SOUTHERLY WIND REGIME ACROSS THE HAWAIIAN WATERS,
ESPECIALLY ACROSS LEEWARD WATERS. FRESH TO LOCALLY STRONG
SOUTHERLY WINDS WERE OBSERVED IN A LATE EVENING ADVANCED
SCATTEROMETER PASS, AND THIS FRESH TO LOCALLY STRONG SOUTHERLY
FLOW WILL CONTINUE THROUGH THE DAY TODAY. A SMALL CRAFT ADVISORY
(SCA) REMAINS IN EFFECT FOR THE WATERS SURROUNDING KAUAI, AND BOTH
LEEWARD AND WINDWARD WATERS OF THE BIG ISLAND HAVE ALSO BEEN
ADDED TO THE SCA WITH THIS MORNING'S UPDATES BASED ON THE LATEST
ASCAT PASS AND HI-RES MODEL GUIDANCE. AFTER A BRIEF LULL IN
SOUTHERLY WIND SPEEDS TONIGHT INTO THURSDAY, REINTENSIFICATION
WILL CAUSE WINDS TO APPROACH, OR POSSIBLY REACH, GALE-FORCE SPEEDS
FOR PORTIONS OF THE AREA AS EARLY AS THURSDAY NIGHT OR FRIDAY,
AND LASTING INTO THE WEEKEND.
A SERIES OF SMALL, MEDIUM- TO LONG-PERIOD WEST-NORTHWEST SWELLS
WILL BRING SMALL SURF TO NORTH AND WEST FACING SHORES THROUGH THE
REST OF THE WEEK. THE FIRST OF THESE WILL PEAK TODAY, RESULTING
IN A SLIGHT BUMP IN SURF ALONG NORTH AND WEST-FACING SHORES. THIS
SWELL WILL THEN DECLINE BEFORE THE NEXT WEST-NORTHWEST SWELL
ARRIVES ON FRIDAY. ADDITIONALLY, A SMALL, MEDIUM- PERIOD NORTH
SWELL IS ALSO EXPECTED TO ARRIVE THURSDAY NIGHT INTO FRIDAY.
CHOPPY SURF ALONG EAST-FACING SHORES WILL CONTINUE TO TREND DOWNWARD,
FALLING BELOW SEASONAL LEVELS TODAY AS WINDS VEER SOUTHERLY. WITH
THE SHIFT OF WIND DIRECTION, SURF ALONG SOUTH-FACING SHORES WILL
INCREASE, BECOMING ROUGH AND CHOPPY. LATER THIS WEEK, ANOTHER
ROUND OF STRONGER SOUTHERLY WINDS FRIDAY INTO THE WEEKEND WILL
CAUSE SOUTH SHORE SURF TO BUILD FURTHER, LIKELY REACHING ADVISORY
LEVELS. A SERIES OF SMALL, LONG-PERIOD SOUTH SWELLS WILL ALSO
MOVE THROUGH.
HFO WATCHES/WARNINGS/ADVISORIES
FLOOD WATCH THROUGH SATURDAY AFTERNOON FOR NIIHAU-KAUAI LEEWARD-
KAUAI MOUNTAINS-WAIANAE COAST-OAHU NORTH SHORE-OLOMANA-CENTRAL
OAHU-WAIANAE MOUNTAINS-KAUAI NORTH-KAUAI EAST-KAUAI SOUTH-EAST
HONOLULU-HONOLULU METRO-EWA PLAIN-KOOLAU WINDWARD-KOOLAU
LEEWARD.
FLOOD WATCH THROUGH SATURDAY AFTERNOON FOR LANAI MAUKA-KAHOOLAWE-
MAUI WINDWARD WEST-MAUI LEEWARD WEST-HALEAKALA SUMMIT-MOLOKAI-
LANAI WINDWARD-LANAI LEEWARD-LANAI SOUTH-MAUI CENTRAL VALLEY
NORTH-MAUI CENTRAL VALLEY SOUTH-WINDWARD HALEAKALA-KIPAHULU-
SOUTH MAUI/UPCOUNTRY-SOUTH HALEAKALA.
HIGH WIND WATCH FROM THURSDAY EVENING THROUGH SUNDAY AFTERNOON
FOR HALEAKALA SUMMIT-BIG ISLAND SUMMITS.
FLOOD WATCH FROM THIS EVENING THROUGH SATURDAY AFTERNOON FOR
KONA-KOHALA-BIG ISLAND INTERIOR-BIG ISLAND SOUTH-BIG ISLAND
SOUTHEAST-BIG ISLAND EAST-BIG ISLAND NORTH.
WINTER STORM WATCH FROM THURSDAY EVENING THROUGH SATURDAY
AFTERNOON FOR BIG ISLAND SUMMITS.
SMALL CRAFT ADVISORY UNTIL 6 PM HST THIS EVENING FOR KAUAI
NORTHWEST WATERS-KAUAI WINDWARD WATERS-KAUAI LEEWARD WATERS-
KAUAI CHANNEL-BIG ISLAND WINDWARD WATERS-BIG ISLAND LEEWARD
WATERS.
DISCUSSION...GIBBS
AVIATION...KINO
MARINE...VAUGHAN
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