577
FXHW60 PHFO 072007
AFDHFO
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HONOLULU HI
1000 AM HST SAT MAR 7 2026
SYNOPSIS
MODERATE TO BREEZY EAST SOUTHEAST WINDS AND MAINLY STABLE
CONDITIONS ARE EXPECTED THIS WEEKEND. A SIGNIFICANT PATTERN CHANGE
WILL BEGIN EARLY NEXT WEEK AS A DEEP LOW PRESSURE SYSTEM EVOLVING
NORTHWEST OF THE ISLANDS TURNS WINDS FROM THE SOUTH. THIS
SOUTHERLY FLOW WILL ALLOW DEEP TROPICAL MOISTURE TO MOVE
NORTHWARD AND OVERRUN THE STATE. THIS SCENARIO WILL INCREASE THE
CHANCES FOR HEAVY RAINFALL, THUNDERSTORMS AND STRONG WINDS NEXT
WEEK. THESE IMPACTS HAVE A HIGHER PROBABILITY OF STARTING OVER
THE WESTERN WATERS AND FROM OAHU WESTWARD LATE MONDAY. THIS
ACTIVITY IS FORECAST TO ADVANCE EAST AND IMPACT THE ENTIRE ISLAND
CHAIN THROUGH THE MIDDLE AND LATTER PART OF NEXT WEEK. THE SLOW-
MOVING NATURE OF THIS SYSTEM TO THE WEST SIGNALS THAT THIS ACTIVE
WEATHER PATTERN MAY PERSIST INTO NEXT WEEKEND.
SHORT TERM UPDATE
ISSUED AT 914 AM HST SAT MAR 7 2026
A SURFACE RIDGE AXIS JUST WEST OF THE ISLAND CHAIN IS WHAT IS
ULTIMATELY MAINTAINING A RELATIVELY PLEASANT START TO THIS FIRST
SATURDAY OF MARCH. SCATTERED CUMULUS MOVING IN ON PREDOMINANT EAST
FLOW AND PILING UP ALONG WINDWARD UPSLOPE MAUKA AS CONVECTIVE BLOW
OFF CIRRUS FROM A LINE OF THUNDERSTORMS A FEW HUNDRED MILES WEST OF
NIIHAU PASSES ACROSS WITHIN UPPER LEVEL WESTERLIES. GENERALLY PARTLY
CLOUDY CONDITIONS WITH LATE MORNING UPPER 70S WARMING A FEW MORE
DEGREES INTO THE LOWER 80S ALONG MORE WIND PROTECTED, LEEWARD
COASTAL AREAS...REMAINING IN THE UPPER 70S IN WINDWARD COMMUNITIES.
LOWER ELEVATION DEW POINTS IN THE MID 60S, ALONG WITH A FAIRLY STOUT
BREEZE, WILL MAKE FOR A COMFORTABLE DAY WITHIN NON-WIND PROTECTED
AREAS. TODAY'S RAIN BEHAVIOR WILL TYPICALLY BE CONFINED TO WINDWARD,
EAST OR SOUTHEAST-FACING SPOTS AND WITHIN HIGHER TERRAIN WHERE MORE
OVERCAST AND RAIN WILL KEEP TEMPERATURES IN THE 60S BETWEEN 3-5 K
FT. A MAINLY CLEAR LEEWARD, PARTIALLY TO OVERCAST WINDWARD SATURDAY
NIGHT WITH OCCASIONAL QUICK-HITTING TRADE SHOWERS GOING INTO SUNDAY
SUNRISE. TOMORROW WILL BE VERY SIMILAR TO TODAY CONCERNING
TEMPERATURE, SKY AND RAIN CHANCES. THE PATTERN BEGINS TO UNDERGO
SOME MAJOR CHANGE LATER MONDAY, ESPECIALLY FROM OAHU WESTWARD, AS
THE NEXT UPPER LOW AND ITS ASSOCIATED FEATURES BEGIN TO EVOLVE FAR
NORTHWEST OF THE STATE.
PREV DISCUSSION
A NOTABLE SHIFT IN THE LARGE-SCALE PATTERN IS EXPECTED TO UNFOLD
ACROSS THE HAWAIIAN ISLANDS DURING THE UPCOMING WEEK. THE CURRENT
DRY AND FAIRLY STABLE REGIME, CHARACTERIZED BY MODERATE TO LOCALLY
BREEZY EAST-SOUTHEAST TRADE FLOW, WILL HOLD IN PLACE THROUGH THE
WEEKEND. CONDITIONS WILL THEN BEGIN TO CHANGE LATE MONDAY INTO
MONDAY NIGHT AS A DEEP UPPER TROUGH DEVELOPS AND AMPLIFIES
NORTHWEST OF THE ISLANDS, BRINGING A MULTI-FACETED WEATHER EVENT
TO THE STATE THAT COULD INCLUDE HEAVY RAINFALL WITH FLASH FLOODING
POTENTIAL, STRONG TO SEVERE STORMS, AND STRONG KONA WINDS.
MODEL GUIDANCE CONTINUES TO INDICATE A STRONG JET STREAK, WITH
CORE WINDS AROUND 120 TO 140 KT AT 250 MB, DIGGING SOUTHEAST
ALONG THE WESTERN FLANK OF THE EVOLVING TROUGH. AS THIS OCCURS,
THE TROUGH IS EXPECTED TO ACQUIRE A MORE NEGATIVE TILT AND EXPAND
TOWARD THE ISLAND CHAIN. THE ISLANDS WILL INCREASINGLY COME UNDER
THE INFLUENCE OF THE JET STREAK’S LEFT-EXIT REGION, PROMOTING
ENHANCED UPPER-LEVEL DIVERGENCE ALOFT. THIS LARGE-SCALE ASCENT,
COMBINED WITH SMALLER SHORTWAVE DISTURBANCES ROTATING AROUND THE
BASE OF THE TROUGH, COULD GENERATE PERIODS OF ORGANIZED CONVECTION
THROUGH MUCH OF NEXT WEEK, POTENTIALLY BEGINNING AS EARLY AS
TUESDAY.
AT THE SURFACE, GLOBAL AND ENSEMBLE GUIDANCE ARE FAIRLY
CONSISTENT IN DEPICTING A BROAD CYCLONIC CIRCULATION DEVELOPING
NORTHWEST OF THE STATE BY EARLY NEXT WEEK IN RESPONSE TO STRONG
UPPER HEIGHT FALLS. CENTRAL PRESSURES NEAR 985 TO 990 MB ARE
POSSIBLE WITH THIS FEATURE REMAINING WELL NORTHWEST OF THE
ISLANDS. THE RESULTING PRESSURE PATTERN WILL SUPPORT STRENGTHENING
SOUTH TO SOUTHEAST WINDS ACROSS THE STATE, ALLOWING A PLUME OF
DEEP TROPICAL MOISTURE TO SURGE NORTHWARD INTO THE REGION.
PRECIPITABLE WATER VALUES ARE EXPECTED TO CLIMB INTO THE 1.7 TO 2
INCH RANGE BY TUESDAY OVER THE WESTERN ISLANDS, THEN SPREAD ACROSS
THE REMAINDER OF THE STATE BY MIDWEEK.
THE EVOLVING THERMODYNAMIC AND KINEMATIC ENVIRONMENT, INCLUDING
UPPER HEIGHT FALLS, COOLER AIR ALOFT, AND INCREASING DEEP-LAYER
SHEAR, WILL FAVOR EPISODES OF HEAVY RAINFALL WITH EMBEDDED
THUNDERSTORMS. COMBINED WITH BROAD CONFLUENT SOUTH-SOUTHEAST FLOW
AND ISLAND TERRAIN EFFECTS, THIS PATTERN COULD SUPPORT TRAINING
AND ANCHORED CONVECTION, PARTICULARLY ALONG FAVORED TERRAIN, SUCH
AS THE KOOLAUS. THIS RAISES THE POTENTIAL FOR SIGNIFICANT
FLOODING CONCERNS IF HEAVIER RAINFALL BANDS PERSIST OVER THE SAME
AREAS. IN ADDITION TO THE HEAVY RAINFALL THREAT, SOME STORMS COULD
BECOME STRONG, AND OCCASIONALLY SEVERE, BY THE MIDDLE OF NEXT
WEEK WITH LOCALLY DAMAGING WINDS POSSIBLE.
IMPACTS MAY BEGIN TO DEVELOP ACROSS THE WESTERN ISLANDS AS EARLY
AS MONDAY NIGHT AS THE LEADING EDGE OF THE MOISTURE PLUME REACHES
THE STATE. THE RISK FOR HEAVY RAIN AND THUNDERSTORMS WILL LIKELY
EXPAND EASTWARD ACROSS THE REMAINDER OF THE ISLAND CHAIN TUESDAY
INTO WEDNESDAY AS DEEPER MOISTURE AND STRONGER FORCING FOR ASCENT
OVERSPREAD THE REGION.
WHILE DETAILS REGARDING THE EXACT TIMING AND LOCATION OF THE
HEAVIEST RAINFALL REMAIN UNCERTAIN, CONFIDENCE CONTINUES TO
INCREASE THAT A PROLONGED PERIOD OF UNSETTLED AND POTENTIALLY
IMPACTFUL WEATHER WILL AFFECT THE ISLANDS NEXT WEEK. FLOODING
IMPACTS COULD BECOME MORE PRONOUNCED OVER TIME AS SOILS BECOME
SATURATED AND STREAM LEVELS AND RESERVOIRS BECOME ELEVATED.
RESIDENTS AND INTERESTS ACROSS THE STATE SHOULD CONTINUE TO
MONITOR FORECASTS THROUGH THE WEEKEND AS THIS SYSTEM COMES INTO
BETTER FOCUS AND DETAILS REGARDING THE TIMING AND LOCATION OF
IMPACTS BECOME CLEARER.
AVIATION
ISSUED AT 914 AM HST SAT MAR 7 2026
SCATTERED TO BROKEN HIGH CLOUDS WILL MOVE OVER THE STATE TODAY.
BRISK EAST SOUTHEAST FLOW ACROSS HAWAII EXPECTED TODAY WITH A
SLIGHT WEAKENING BY SUNDAY. WINDS WILL CARRY IN SCATTERED CLOUDS
THAT WILL ANCHOR OVER SOUTHEAST SLOPES AND BRING ISOLATED MVFR
CEILINGS AND BRIEF MOUNTAIN OBSCURATIONS, INCREASING A BIT TONIGHT
ACROSS KAUAI AND BIG ISLAND.
AIRMET TANGO IN EFFECT FOR TEMPO MODERATE TURBULENCE BELOW 7000
FEET ACROSS DOWNWIND SLOPES (SOUTH ACROSS NORTHWEST FACING).
EXPECT THIS AIRMET TO CONTINUE THROUGH THE DAY THEN DROPPING OFF
TONIGHT OR SUNDAY. DIRECTIONAL LLWS POSSIBLE AT THE PHOG/OGG
RUNWAY.
MARINE
ISSUED AT 914 AM HST SAT MAR 7 2026
STRONG HIGH PRESSURE FAR TO THE NORTHEAST OF THE STATE WILL
MAINTAIN FRESH TO STRONG TRADE WINDS THROUGH THE WEEKEND, WITH
THE STRONGEST WINDS OVER THE TYPICALLY WINDY AREAS AROUND MAUI
COUNTY AND THE BIG ISLAND. A SMALL CRAFT ADVISORY IS NOW IN
EFFECT FROM THE WINDWARD OAHU WATERS AND KAIWI CHANNEL EASTWARD
THROUGH 6 PM SUNDAY, WITH THE EXCEPTION OF MAALAEA BAY. THIS SCA
MAY NEED TO BE EXTENDED FOR PORTIONS OF THE MARINE AREA 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 AND WEDNESDAY.
SURF ALONG EAST FACING SHORES WILL REMAIN ELEVATED AND CHOPPY
THROUGH 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 THROUGH EARLY
NEXT WEEK, WITH THE EXCEPTION OF AREAS EXPOSED TO TRADE WIND SWELL
WRAP. ROUGH AND CHOPPY CONDITIONS APPEAR TO DEVELOP TUESDAY AND
CONTINUE THROUGH LATE NEXT 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 NEXT 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...BLOOD
DISCUSSION...GIBBS
AVIATION...FOSTER
MARINE...VAUGHAN
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