161
FXHW60 PHFO 021326
AFDHFO
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HONOLULU HI
326 AM HST THU JAN 2 2025
SYNOPSIS
MODERATE TO LOCALLY BREEZY TRADES WILL CONTINUE THROUGH TODAY WITH
CLOUDS AND SHOWERS FAVORING WINDWARD AND MAUKA AREAS. OVERNIGHT
LAND BREEZES AND AFTERNOON SEA BREEZE PATTERN WILL TAKE OVER
FRIDAY THROUGH EARLY NEXT WEEK AS WINDS WEAKEN TO LIGHT TO GENTLE
SOUTHERLY BACKGROUND FLOW. A COLD FRONT MAY MOVE OVER PORTIONS OF
THE STATE MIDDLE OF NEXT WEEK.
DISCUSSION
SATELLITE AND RADAR IMAGERY SHOW ISOLATED TO SCATTERED SHOWERS
MOVING INTO MAINLY WINDWARD AND MAUKA AREAS EARLY THIS MORNING AS
A PLUME OF MOISTURE RIDES IN ON THE TRADES. SURFACE RIDGING TO
THE NORTH AND NORTHEAST OF THE STATE WILL HELP TO MAINTAIN
MODERATE TO LOCALLY BREEZY TRADES ACROSS THE ISLAND CHAIN THROUGH
TODAY. CONTINUE TO EXPECT CLOUDS AND SHOWERS TO FOCUS MAINLY ALONG
WINDWARD AND MAUKA AREAS THROUGH TODAY WITH A TRANSITION TO
SOUTHEASTERLY FLOW LATER TONIGHT INTO FRIDAY AS A FRONT APPROACHES
THE STATE TO THE NORTHWEST.
A WEAK COLD FRONT WILL STALL NORTHWEST OF THE STATE FRIDAY,
PUSHING THE SURFACE RIDGE OVER THE STATE AND ALLOWING WINDS TO
WEAKEN AND VEER OUT OF THE SOUTHEAST THEN OUT OF THE SOUTH
SOUTHWEST SATURDAY INTO EARLY NEXT WEEK. IN THIS WEAKER FLOW,
LAND AND SEA BREEZES WILL BECOME MORE PREVALENT, BRINGING CLOUDS
AND A FEW SHOWERS OVER LEEWARD AND INTERIOR AREAS DURING THE
DAYLIGHT HOURS AND THEN CLEARING OUT OVERNIGHT. SUNDAY INTO EARLY
NEXT WEEK, SOUTHWESTERLY WIND SPEEDS OVER THE WESTERN HALF OF THE
STATE COULD INCREASE CHANCES OF CLOUDS AND SHOWERS FOR LEEWARD
LOCATIONS OF KAUAI AND OAHU AS ANOTHER FRONT APPROACHES THE STATE.
MODEL GUIDANCE SHOWS THAT AN UPPER LEVEL TROUGH WILL DIVE DOWN
AND SWEEP ACROSS THE CENTRAL PACIFIC MIDDLE THROUGH THE SECOND
HALF OF NEXT WEEK THAT COULD HELP DRIVE THE NEXT COLD FRONT
THROUGH AT LEAST A PORTION OF THE ISLAND CHAIN. THIS PATTERN COULD
MAKE FOR MORE ACTIVE SHOWERS ACROSS THE STATE AS THE MOISTURE
ASSOCIATED WITH THE FRONT LINGERS OVER THE STATE AND MODERATE TO
LOCALLY BREEZY TRADES FILL IN BEHIND THE FRONT. HOWEVER, THERE
ARE STILL DIFFERENCES BETWEEN THE GLOBAL MODELS WHICH DECREASES
FORECAST CONFIDENCE TUESDAY AND BEYOND.
FINALLY, A HOT SPOT OVER HALEMAUMAU CRATER ON THE BIG ISLAND
CONTINUES TO BE SEEN ON INFRARED SATELLITE IMAGERY. THE UNIVERSITY
OF HAWAII VOG MODEL SHOWS THAT SO2 EMISSIONS SHOULD REMAIN
CONFINED TO PORTIONS OF THE BIG ISLAND AND ADJACENT WATERS TO THE
WEST AND SOUTHWEST THROUGH TOMORROW. HOWEVER, ASSUMING CONSTANT
SO2 EMISSIONS, VOG WILL LIKELY BEGIN TO INCREASE ACROSS THE REST
OF THE STATE LATE THIS FRIDAY INTO EARLY NEXT WEEK AS WINDS
WEAKEN AND BECOME MORE SOUTHERLY.
AVIATION
MODERATE TO LOCALLY BREEZY TRADE WINDS WILL CONTINUE TODAY, WITH
CLOUDS AND SHOWERS FAVORING WINDWARD AND MAUKA LOCATIONS. EXPECT
PERIODS OF MVFR CIGS/VSBYS IN SHOWERS THROUGH THE MORNING HOURS.
THE TRADES WILL TREND DOWN AND SHIFT OUT OF THE EAST-SOUTHEAST
TONIGHT INTO FRIDAY, TRANSLATING TO A LAND AND SEA BREEZE REGIME
DEVELOPING OVER THE WESTERN END OF THE STATE.
AIRMET SIERRA IS IN EFFECT FOR TEMPO MOUNTAIN OBSCURATION ABOVE
025 IMPACTING NORTH THROUGH EAST SECTIONS MAUI AND MOLOKAI. THIS
MAY NEED TO BE EXPANDED TO THE WINDWARD SECTIONS OF OAHU LATER
THIS MORNING.
AIRMET TANGO IS IN EFFECT FOR TEMPO MODERATE TURBULENCE ABOVE
FL280. THIS SHOULD SHIFT EAST OF THE STATE LATER TODAY IN THE
WAKE OF AN UPPER TROUGH MOVING THROUGH.
MARINE
A HIGH PRESSURE SYSTEM PASSING NORTH OF THE ISLANDS WILL KEEP
FRESH TO LOCALLY STRONG TRADE WINDS BLOWING FOR ONE MORE DAY TODAY.
A SMALL CRAFT ADVISORY REMAINS IN EFFECT FOR THE TYPICAL WINDIER
WATERS AROUND MAUI AND THE BIG ISLAND. TRADE WINDS WILL WEAKEN AND
SHIFT FROM A MORE SOUTHEASTERLY DIRECTION FROM FRIDAY INTO SUNDAY
AS THE HIGH DRIFTS INTO THE EAST PACIFIC AND AN APPROACHING COLD
FRONT STALLS OUT NORTHWEST OF THE STATE. LIGHTER SOUTHEASTERLY
WINDS WILL PLACE MOST ISLANDS, FROM MAUI TO KAUAI, IN THE LEEWARD
WIND AND RAIN SHADOW OF THE BIG ISLAND. THESE WEAKER LARGE SCALE
WINDS WILL CAUSE NEAR SHORE LAND AND SEA BREEZES TO EXPAND IN
COVERAGE DURING THIS TIME PERIOD. SOUTHERLY WINDS DEVELOP ACROSS
THE REGION FROM LATE SUNDAY INTO MONDAY AHEAD OF ANOTHER COLD
FRONT.
AN ACTIVE PERIOD WITH SEVERAL NORTHWEST SWELLS WILL MOVE THROUGH
THE ISLANDS THROUGH THE NEXT SEVEN DAYS. THE FIRST OF SEVERAL
NORTHWEST SWELLS WAS DELAYED A BIT AND WILL STILL BUILD TO
ADVISORY LEVELS LATER TODAY, THEN GRADUALLY DECLINE ON FRIDAY. A
LOW PRESSURE SYSTEM CURRENTLY MOVING THROUGH THE WEST PACIFIC IS
PRODUCING HURRICANE FORCE WINDS ALONG A FETCH THAT LINES UP A
SIGNIFICANT NORTHWEST SWELL POINTED DIRECTLY TOWARDS THE HAWAIIAN
ISLANDS. THIS SIGNIFICANT LONG PERIOD NORTHWEST SWELL WILL SWIFTLY
BUILD INTO THE ISLAND CHAIN THROUGH THE DAY ON SATURDAY, THE
SWELL ENERGY WILL PEAK BY SATURDAY NIGHT AND SUNDAY, AND THEN
SLOWLY LOWER FROM SUNDAY NIGHT INTO MONDAY. THIS SWELL WILL
PRODUCE WARNING LEVEL SURF HEIGHTS ALONG EXPOSED NORTH AND WEST
FACING SHORES THROUGH MUCH OF THE WEEKEND. YET ANOTHER SIGNIFICANT
LONG PERIOD NORTHWEST SWELL WILL ARRIVE FROM LATE MONDAY INTO
TUESDAY, POSSIBLY PUSHING SURF HEIGHTS BACK UP TO WARNING LEVELS,
WITH ANOTHER REINFORCING NORTHWEST SWELL PUSHING SURF HEIGHTS WELL
ABOVE WARNING LEVELS BY NEXT WEEK WEDNESDAY.
SURF ALONG EAST AND SOUTH FACING SHORES WILL REMAIN SMALL THROUGH
THE FIRST HALF OF NEXT WEEK.
FIRE WEATHER
NO CRITICAL FIRE WEATHER CONDITIONS ARE EXPECTED FOR THE NEXT
SEVEN DAYS. MODERATE TO LOCALLY BREEZY TRADE WINDS WILL GRADUALLY
EASE LATE TONIGHT INTO FRIDAY. LAND/SEABREEZE PATTERN WILL
DEVELOP FRIDAY INTO EARLY NEXT WEEK AS A WEAK SOUTHERLY
BACKGROUND FLOW TAKES OVER. RELATIVE HUMIDITIES WILL STAY ABOVE
CRITICAL LEVELS THROUGH THE FORECAST PERIOD. A FRONT MAY MOVE
THROUGH THE STATE BY MID WEEK NEXT WEEK THAT COULD PROVIDE MUCH
NEEDED RAINFALL TO LEEWARD LOCATIONS.
HFO WATCHES/WARNINGS/ADVISORIES
HIGH SURF ADVISORY UNTIL 6 AM HST FRIDAY FOR NORTH AND WEST FACING
SHORES OF NIIHAU KAUAI OAHU MOLOKAI AND NORTH FACING SHORES OF
MAUI.
SMALL CRAFT ADVISORY UNTIL 6 PM HST THIS EVENING FOR MAALAEA BAY-
PAILOLO CHANNEL-ALENUIHAHA CHANNEL-BIG ISLAND LEEWARD WATERS-BIG
ISLAND SOUTHEAST WATERS.
DISCUSSION...ALMANZA
AVIATION...GIBBS
MARINE...BOHLIN
FIRE WEATHER...ALMANZA
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page