466
FXHW60 PHFO 080645
AFDHFO
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HONOLULU HI
845 PM HST SAT MAR 7 2026
SYNOPSIS
THE HIGH PRESSURE RIDGE NORTH OF THE ISLANDS WILL WEAKEN THROUGH
MONDAY AS A STRONG CUT OFF LOW PRESSURE SYSTEM DEEPENS NEAR THE
DATELINE. WIND DIRECTIONS WILL VEER MORE SOUTHEASTERLY ON MONDAY,
THEN STRENGTHENING SOUTHERLY WINDS FROM TUESDAY ONWARD. THIS NEXT
SYSTEM IS EXTREMELY STRONG FOR THE HAWAII REGION AND DANGEROUS
IMPACTS ARE LIKELY TO DEVELOP STATEWIDE THROUGH MUCH OF NEXT WEEK.
A COMBINATION OF FLOODING, STRONG AND GUSTY SOUTHERLY WINDS,
THUNDERSTORMS, AND BIG ISLAND SUMMIT LEVEL SNOW AND ICE WILL
THREATEN HAWAII FROM TUESDAY THROUGH NEXT WEEKEND. ISLAND BY
ISLAND IMPACTS WILL BE DRIVEN BY BOTH LARGE SCALE TROUGHS AND
SMALLER SCALE THUNDERSTORM BANDS OVER THE ENTIRE DURATION OF THIS
SEVERE WEATHER EVENT.
SHORT TERM UPDATE
THE SATELLITE IMAGERY THIS EVENING SHOWS A STRONG LOW PRESSURE
SYSTEM DEEPENING NEAR THE INTERNATIONAL DATELINE, DRIFTING SLOWLY
TOWARDS THE HAWAIIAN ISLANDS. A SIGNIFICANT BAND OF THUNDERSTORMS
CONTINUES TO DEVELOP ROUGHLY 500 TO 700 MILES EAST TO SOUTHEAST
OF THE LOW'S CENTER. A BAND OF HIGH LEVEL CLOUDS EVEN FARTHER
AWAY FROM THE LOW, SHOWS EMBEDDED THUNDERSTORMS ALREADY DEVELOPING
WITHIN 200 TO 300 MILES WEST OF KAUAI.
CLOSER TO THE HAWAIIAN ISLANDS WE SEE SOME UNSTABLE CUMULUS
CLOUDS MOVING IN FROM THE EAST, PRODUCING PERIODS OF SHOWERS ALONG
THE EASTERN SLOPES OF THE BIG ISLAND AND MAUI. THESE SHOWERS WILL
BRING A BRIEF INCREASE IN CLOUDS AND SHOWERS TO ALL ISLANDS
THROUGH THE EARLY MORNING HOURS.
PREVIOUS DISCUSSION
ISSUED AT 429 PM HST SAT MAR 7 2026
STABLE WEATHER CONDITIONS THIS AFTERNOON AS THE ISLANDS REMAIN
UNDER THE SUBTLE INFLUENCE OF WEAK SURFACE RIDGING LOCATED JUST
WEST OF THE STATE. THE PRESSURE GRADIENT DOWNSTREAM OF A LARGE
1038 MB HIGH HAS BEEN TAUNT ENOUGH TO PRODUCE BREEZY TRADES IN
THE 10 TO 20 MPH RANGE, OCCASIONALLY EXCEEDING 25 MPH IN GUST
THROUGH NOTORIOUSLY WINDY PASSAGES/VALLEYS. TODAY'S RAIN BEHAVIOR
WAS VERY LIGHT AND SPOTTY AND CONFINED TO WINDWARD OR INTERIOR
UPPER TERRAIN WHERE THE 24 HOUR RAIN ACCUMULATION WINNER WAS
UNSURPRISINGLY MT. WAIALEALE ON KAUAI WITH 1.25 INCHES. OVERNIGHT
CONDITIONS WILL BE MAINLY CLEAR LEEWARD, PARTIALLY TO OVERCAST
WINDWARD WITH THE INFREQUENT QUICK-HITTING LIGHT TRADE SHOWER.
TOMORROW WILL BE VERY SIMILAR TO TODAY AS IT RELATES TO WIND,
CLOUD COVERAGE AND RAIN CHANCES. THE ONLY MINOR CHANGE WILL THE
SLIGHTLY GREATER COVERAGE OF MEASURABLE PRIMARILY WINDWARD RAIN AS
THE BOUNDARY LAYER MOISTENS UP. THE PATTERN BEGINS TO UNDERGO
CHANGE MONDAY, ESPECIALLY FROM OAHU WESTWARD, AS A DEVELOPING
UPPER TROUGH AND ITS ASSOCIATED FEATURES BEGIN TO EVOLVE FAR WEST
NORTHWEST OF THE STATE.
WEATHER WILL UNDERGO CHANGE LATE MONDAY AS A DEEP UPPER LEVEL
TROUGH DEVELOPS AND DEEPENS SOUTHWARD NORTHWEST OF THE ISLANDS.
THE TROUGH WILL MOVE EAST VERY SLOWLY AND BEGIN TO EXHIBIT A
NEGATIVE TILT GOING INTO THE MIDDLE OF NEXT WEEK. THIS WILL
INITIATE THE NEXT WEATHER EVENT THAT, BECAUSE OF ITS SLOW
MOVEMENT, WILL LIKELY HANG ON FOR MULTIPLE DAYS. THE MAIN THREATS
WILL BE PERIODS OF HEAVY RAIN THAT WILL CREATE FLASH FLOODING,
PRODUCE STRONG OR SEVERE STORMS AND STRONG KONA WINDS. NWP
GUIDANCE INDICATES A STRONG JET STREAK NOSING IN FROM THE WEST AT
MID WEEK, ALONG WITH A SPLITTING JET WITH THE BASE OF THE TROUGH
POSITIONED OVER THE WESTERN HALF OF THE STATE. THE VICINITY OF THE
JET'S MORE (UPPER DIFLUENT) LEFT EXIT REGION MAY PROMOTE ENHANCED
LARGE SCALE ASCENT THAT IS TYPICALLY REQUIRED FOR THUNDERSTORM
DEVELOPMENT. ALONG WITH THIS JET FORCING, PASSING SHORTWAVE
DISTURBANCES ROTATING AROUND THE BASE OF THE TROUGH AND COOLING
MID TO UPPER LAYERS, WILL BE THE INGREDIENTS THAT WILL INCREASE
CHANCES FOR ORGANIZED CONVECTION THROUGH MID TO LATE WEEK. FALLING
SURFACE PRESSURES NORTHWEST OF THE STATE WILL CREATE A PRESSURE
PATTERN THAT WILL SUPPORT STRENGTHENING SOUTH TO SOUTHEAST (KONA)
STATEWIDE WINDS. THIS WILL PULL UP A PLUME OF RICH TROPICAL
MOISTURE ACROSS THE REGION. AS THE TROUGH LIFTS SLOWLY
NORTHEAST, VERY HIGH PRECIPITABLE WATER VALUES OF OVER 1.7 INCHES
OVER THE WESTERN ISLANDS TUESDAY WILL EXPAND EAST ACROSS THE
REMAINDER OF THE STATE THROUGH WEDNESDAY.
LOWERING HEIGHT FALLS, COOLING AIR ALOFT, AND INCREASING DEEP-
LAYER SHEAR WILL FAVOR EPISODES OF HEAVY RAINFALL WITH EMBEDDED
THUNDERSTORMS. BROAD SOUTH-SOUTHEAST CONFLUENT FLOW RUNNING
PARALLEL WITH THE UPPER TERRAIN COULD SUPPORT TRAINING AND ANCHORED
CONVECTION. THE POTENTIAL FOR SIGNIFICANT FLOODING REMAINS ALIVE
THROUGH LATE IN THE WEEK IF AND WHEN HEAVIER RAIN PERSISTS OVER
THE SAME LOCALS (SIMILAR TO WHAT OCCURRED OVER THE KOOLAUS A
COUPLE OF WEEKS AGO). FLOODING IMPACTS COULD BECOME MORE
PRONOUNCED OVER TIME AS SOILS BECOME SATURATED AND STREAM /
RESERVOIR LEVELS RISE. IN ADDITION TO THE FLOODING THREAT,
THUNDERSTORMS COULD BECOME STRONG, POSSIBLY SEVERE, BY THE MIDDLE
OF NEXT WEEK. ANOTHER THREAT WILL BE STRONG SOUTHERLY WINDS ATOP
RIDGE TOPS AND ALONG LEEWARD SLOPES. DOWNSLOPE WINDS WEDNESDAY
COULD BECOME STRONG ENOUGH TO THROW LIGHT WEIGHT OBJECTS ABOUT,
KNOCK OUT POWER, CAUSE MINOR STRUCTURE DAMAGE, BREAK OFF TREE
LIMBS AND FALL WEAKER ROOTED TREES. PLEASE MONITOR SUBSEQUENT
FORECASTS THROUGH MONDAY AS DETAILS REGARDING THE EXACT TIMING AND
LOCATION OF THE HEAVIEST RAIN AND STRONGEST WIND COME INTO BETTER
FOCUS.
AVIATION
ISSUED AT 845 PM HST SAT MAR 7 2026
EAST SOUTHEAST FLOW ACROSS HAWAII IS EXPECTED TO SLIGHTLY WEAKEN
TOMORROW. SCATTERED CLOUDS WILL MOVE IN AND BRINGING SHRA OVER
SOUTHEAST AREAS. MVFR CONDS POSSIBLE IN SHRA, OTHERWISE VFR CONDS
PREVAIL.
AIRMET SIERRA FOR MTN OBSC IS IN EFFECT FOR WINDWARD LOCATIONS OF
KAUAI, OAHU, MAUI AND THE BIG ISLAND.
AIRMET TANGO IN EFFECT FOR MOD TURB BLW 080 DOWNWIND SLOPES
(SOUTH ACROSS NORTHWEST FACING). EXPECT THIS AIRMET TO DROP OFF
IN THE MORNING. DIRECTIONAL LLWS POSSIBLE AT THE PHOG/OGG RUNWAY
SUNDAY AFTERNOON.
MARINE
ISSUED AT 429 PM HST SAT MAR 7 2026
STRONG HIGH PRESSURE FAR NORTHEAST OF THE STATE WILL MAINTAIN
FRESH TO STRONG TRADE WINDS THROUGH THE REST OF THE WEEKEND, WITH
THE STRONGEST WINDS OVER THE CENTRAL AND EASTERN COASTAL WATERS
(WITH THE EXCEPTION OF MAALAEA BAY). A SMALL CRAFT ADVISORY
REMAINS IN EFFECT FOR THESE AREAS THROUGH 6 PM SUNDAY, THOUGH THIS
MAY NEED TO BE EXTENDED FOR THE TYPICALLY WINDY CHANNELS AND
WATERS OF MAUI COUNTY AND THE BIG ISLAND THROUGH SUNDAY NIGHT. A
FRONT APPROACHING FROM THE WEST WILL EASE THE TRADES AND SHIFT
THEM SOUTHEASTERLY ON MONDAY, WITH THE WINDS THEN BECOMING
SOUTHERLY AND INCREASING TO FRESH TO STRONG LEVELS TUESDAY THROUGH
THE REST OF THE WEEK.
SURF ALONG EAST FACING SHORES WILL REMAIN ELEVATED AND CHOPPY
THROUGH THE REST OF THE WEEKEND, TREND DOWNWARD ON MONDAY, THEN
LOWER BELOW NORMAL LEVELS TUESDAY THROUGH LATE NEXT WEEK.
A SERIES OF WEST-NORTHWEST SWELLS WILL KEEP SOME SMALL SURF IN
PLACE ALONG NORTH AND WEST FACING SHORES DURING THE NEXT 7 DAYS,
BUT SURF WILL REMAIN WELL BELOW ADVISORY LEVELS. A SMALL TO
MODERATE SIZED NORTH SWELL IS POSSIBLE AROUND THURSDAY AND FRIDAY
OF NEXT WEEK.
SURF ALONG SOUTH-FACING SHORES WILL REMAIN SMALL, WITH THE
EXCEPTION OF AREAS EXPOSED TO TRADE WIND SWELL WRAP. ROUGH AND
CHOPPY CONDITIONS WILL DEVELOP TUESDAY AND CONTINUE THROUGH LATE
WEEK AS SOUTHERLY WINDS INCREASE IN ADVANCE OF A FRONT. A SERIES
OF SMALL LONG PERIOD SOUTH SWELLS WILL ALSO MOVE THROUGH MONDAY
THROUGH LATE WEEK.
HFO WATCHES/WARNINGS/ADVISORIES
SMALL CRAFT ADVISORY UNTIL 6 PM HST SUNDAY FOR ALENUIHAHA
CHANNEL-BIG ISLAND LEEWARD WATERS-BIG ISLAND SOUTHEAST WATERS-
BIG ISLAND WINDWARD WATERS-KAIWI CHANNEL-MAUI COUNTY LEEWARD
WATERS-MAUI COUNTY WINDWARD WATERS-OAHU WINDWARD WATERS-PAILOLO
CHANNEL.
SHORT TERM UPDATE...BOHLIN
PREVIOUS DISCUSSION...BLOOD
AVIATION...WALSH
MARINE...VAUGHAN
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