551
FXHW60 PHFO 301339
AFDHFO
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HONOLULU HI
339 AM HST SAT NOV 30 2024
SYNOPSIS
TRADE WINDS WILL WEAKEN TODAY, BECOMING LIGHT AND VARIABLE WINDS
FROM SUNDAY INTO THE FIRST HALF NEXT WEEK. WEATHER CONDITIONS IN
THIS LIGHT WIND PATTERN WILL REMAIN FAIRLY STABLE WITH PASSING LOW
CLOUDS AND LIGHT SHOWERS ESPECIALLY DURING THE AFTERNOON. RAIN
CHANCES INCREASE FROM THURSDAY INTO FRIDAY AS A WEAK COLD FRONT
MOVES INTO AND STALLS OUT OVER THE ISLANDS.
DISCUSSION
HIGH LEVEL CIRRUS CLOUDS ARE STREAMING IN FROM WEST TO EAST ACROSS
THE ISLAND CHAIN DUE TO A SUBTROPICAL JET STREAM IN THE UPPER
ATMOSPHERE. THE LOW LEVEL CLOUDS LOOK FAIRLY STABLE IN THIS
MORNING SATELLITE IMAGERY AND STABLE CONDITIONS ALOFT WILL TEND TO
LIMIT SHOWER ACTIVITY FAVORING ISLAND MOUNTAINS AND INTERIOR
SECTIONS EACH AFTERNOON THROUGH THE WEEKEND. UPPER AIR WEATHER
BALLOON SOUNDINGS FROM LIHUE, KAUAI AND HILO, HAWAII SHOW
SUBSIDENCE TEMPERATURE INVERSION HEIGHTS AROUND THE 6,000 FEET
ELEVATION LEVEL. THESE STABLE TEMPERATURE INVERSION HEIGHTS WILL
TEND TO LIMIT CLOUD GROWTH AND GENERALLY PRODUCE BRIEF PERIODS OF
ISOLATED TO SCATTERED SHOWER ACTIVITY.
THE SUBTROPICAL RIDGE AXIS CURRENTLY OVER THE ISLANDS KEEPING
FAIRLY STABLE CONDITIONS IN THE FORECAST WILL DRIFT SOUTH OF THE
STATE FROM SUNDAY ONWARD. EXPECT A SLIGHT INCREASE IN SHOWER
TRENDS DURING THE FIRST HALF OF NEXT WEEK IN A LIGHT WIND
AFTERNOON ONSHORE SEA BREEZE WEATHER REGIME. CLOUDS AND A FEW
SHOWERS WILL DEVELOP BY LATE MORNING TO AFTERNOON OVER ISLAND
MOUNTAIN AND INTERIOR SECTIONS THROUGH WEDNESDAY. RAINFALL AMOUNTS
WILL BE LIGHT DUE TO THE LARGE SCALE ATMOSPHERIC STABILITY.
BY THURSDAY, LONG RANGE MODEL GUIDANCE CONTINUES TO SHOW A SHALLOW
COLD FRONT CREEPING INTO THE WESTERN ISLANDS FROM THE NORTHWEST
DIRECTION. WIDESPREAD SHOWERS AND BREEZY TRADE WINDS WILL DEVELOP
ALONG THE WEAKENING FRONTAL BAND AS IT PASSES THROUGH EACH
ISLAND, STALLING OUT NEAR MAUI BY FRIDAY MORNING. ALL ISLANDS WILL
BENEFIT FROM A PERIOD OF ENHANCED SHOWERS ALONG THE FRONTAL BAND,
ESPECIALLY ALONG THE WINDWARD AND MOUNTAIN SLOPES OF EACH ISLAND.
THE FRONTAL BAND WILL THEN BREAK APART BY FRIDAY AFTERNOON,
WITH REMNANT UNSTABLE CLOUD BANDS DRIFTING INTO EACH ISLAND ON
THE STRENGTHENING EASTERLY TRADE WINDS.
AVIATION
LIGHT TO MODERATE TRADES WEAKEN THROUGH THE WEEKEND, ALLOWING FOR
LOCALIZED LAND/SEA BREEZE DEVELOPMENT. ANOTHER BAND OF MOISTURE
RIDING THE TRADES SHOULD MOVE IN OVERNIGHT INCREASING SHRA AND LOW
CIGS MOSTLY ALONG WINDWARD AND MAUKA LOCATIONS. MVFR CONDS CAN BE
EXPECTED IN ANY SHRA BUT OTHERWISE VFR SHOULD PREVAIL.
AIRMET TANGO IS IN EFFECT FOR MOD TURB BETWEEN FL250 AND FL450
ACROSS THE STATE.
SIGMET PAPA FOR SEVERE UPPER LEVEL TURB IS IN EFFECT FOR AN AREA
JUST WEST OF THE MAIN HAWAIIAN ISLANDS THIS EVENING. THIS AREA OF
SEVERE TURB IS EXPECTED TO MOVE OVER THE ISLANDS LATE TONIGHT
INTO SATURDAY MORNING.
MARINE
A FRONT APPROACHING FROM THE NORTHWEST WILL STALL AND WEAKEN
NORTHWEST OF THE COASTAL WATERS THIS WEEKEND. LIGHT BACKGROUND
FLOW WILL SHIFT TO SOUTHEASTERLIES BY SUNDAY. ANOTHER FRONT
WILL APPROACH FROM THE NORTHWEST EARLY NEXT WEEK WILL KEEP GENTLE
SOUTH TO SOUTHEAST WINDS IN PLACE.
AN EXTRA-LARGE NORTHWEST (310-320) SWELL PEAKED OVERNIGHT AND IS
STARTING TO DECLINE. HOWEVER, THIS SWELL WILL CONTINUE TO
GENERATE SURF HEIGHTS IN EXCESS OF WARNING THRESHOLD ALONG
AFFECTED NORTH AND WEST FACING SHORELINES THROUGH TODAY. A HIGH
SURF WARNING (HSW) REMAINS IN EFFECT THROUGH 6PM HST THIS EVENING
FOR MOST NORTH AND WEST-FACING SHORES OF THE SMALLER ISLANDS AND
FOR WEST FACING SHORES OF THE BIG ISLAND. EXPECT PERIODIC
OVERTOPPING OF VULNERABLE COASTAL ROADWAYS AND WAVE RUNUP TO
COASTAL PROPERTIES. A GRADUAL DOWNWARD TREND WILL CONTINUE THROUGH
THIS WEEKEND AND SURF SHOULD DECREASE BELOW ADVISORY THRESHOLD
DURING THE DAY SUNDAY. IN ADDITION, A SMALL CRAFT ADVISORY (SCA)
REMAINS IN EFFECT FOR MOST COASTAL WATERS FOR SEAS GREATER THAN
10 FT. THIS SCA IS EXPECTED TO HOLD THROUGH TODAY.
LOOKING AHEAD INTO NEXT WEEK, A STRETCH OF ELEVATED NORTH AND WEST
SHORE SURF IS EXPECTED, PRODUCED BY OVERLAPPING NORTHWEST PULSES
RANGING FROM LARGE TO POTENTIALLY EXTRA-LARGE, PARTICULARLY FROM
WEDNESDAY ONWARD. SURF ALONG EAST FACING SHORES WILL REMAIN
SLIGHTLY ELEVATED THROUGH THE WEEKEND DUE TO THE LINGERING SHORT-
PERIOD NORTH- NORTHEAST SWELL. EARLY NEXT WEEK, EAST FACING SHORE
SURF WILL REMAIN SMALL. SURF ALONG SOUTH FACING SHORES WILL SEE
AN UPTICK HEADING INTO NEXT WEEK FROM A SERIES OF CONSECUTIVE
SOUTHWEST PULSES. THIS WILL RESULT IN SMALL TO MODERATE SURF,
PEAKING MONDAY AND TUESDAY.
FIRE WEATHER
CRITICAL FIRE WEATHER CONDITIONS ARE NOT EXPECTED THROUGH EARLY
NEXT WEEK AS WINDS REMAIN BELOW WARNING THRESHOLDS. DAYTIME
RELATIVE HUMIDITY MAY BRIEFLY TOUCH CRITICAL LEVELS OVER DRIER
LEEWARD ZONES INTO NEXT WEEK.
HFO WATCHES/WARNINGS/ADVISORIES
HIGH SURF WARNING UNTIL 6 PM HST THIS EVENING FOR NIIHAU-KAUAI
LEEWARD-WAIANAE COAST-OAHU NORTH SHORE-MAUI WINDWARD WEST-KONA-
KOHALA-KAUAI NORTH-KOOLAU WINDWARD-MOLOKAI WINDWARD-MOLOKAI
NORTH-MOLOKAI WEST-WINDWARD HALEAKALA.
SMALL CRAFT ADVISORY UNTIL 6 PM HST THIS EVENING FOR ALL
HAWAIIAN WATERS EXCEPT MAALAEA BAY-
DISCUSSION/FIRE WEATHER...BOHLIN
AVIATION...WALSH
MARINE...POWELL
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