599
FXHW60 PHFO 011907
AFDHFO
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HONOLULU HI
907 AM HST SAT AUG 1 2026
SYNOPSIS
STRONG HIGH PRESSURE WILL HOLD THROUGH THIS AFTERNOON BEFORE
WEAKENING TONIGHT THROUGH THE NEXT SEVERAL DAYS. AS A RESULT, THE
WINDY TRADE WINDS COULD REMAIN HAZARDOUS THIS AFTERNOON THROUGH
TONIGHT AND WILL GRADUALLY DECREASE BACK DOWN TO NORMAL LEVELS
TOMORROW INTO NEXT WEEK. SHOWERS WILL FAVOR WINDWARD AND MOUNTAIN
AREAS, STAYING ON THE LIGHTER SIDE THROUGH THE NEXT FEW DAYS
BEFORE POTENTIALLY INCREASING SLIGHTLY DURING THE MIDDLE OF NEXT
WEEK.
DISCUSSION
WINDY TRADE WINDS ARE EXPECTED TO BLOW THROUGH THIS AFTERNOON WITH
A LITTLE MORE SHOWERS THAN EXPECTED PASSING THROUGH WINDWARD AND
MOUNTAIN AREAS. BASED ON SATELLITE AND RADAR, MOST OF THESE
SHOWERS SEEM TO BE MOVING OVER OAHU AND KAUAI, AND ARE ON THE
LIGHTER SIDE. THE WIND ADVISORY FOR THE BIG ISLAND HAS BEEN
CANCELLED DUE TO A DECREASE IN SUMMIT LEVEL WINDS. THE MAIN TOPIC
IN FOCUS FOR TODAY WILL BE HOW LONG THE ADVISORY LEVEL WINDS WILL
LAST FOR THE REST OF THE STATE. CURRENT HIGHRES MODEL GUIDANCE
SUGGESTS THAT STRONG TO WINDY TRADE WINDS WITH 50 MPH GUSTS COULD
LINGER THROUGH A GOOD PORTION OF TONIGHT, THEREFORE THERE IS A
POSSIBILITY THAT THE HIGH WIND ADVISORY WILL BE EXTENDED THROUGH
THE OVERNIGHT HOURS. WE WILL BE MONITORING THE WINDS TODAY AND SEE
HOW THEY COMPARE TO THE MODEL GUIDANCE. THE STRONGEST WINDS WILL
BE FELT OVER THE WINDY AREAS ALONG RIDGES, THROUGH MOUNTAINOUS
GAPS AND DOWNSLOPE MOUNTAIN AREAS.
THE HIGH PRESSURE WILL DRIFT EASTWARD ON SUNDAY, LOOSENING LOCAL
PRESSURE GRADIENTS, AND EASING TRADES BACK DOWN TO TYPICAL
SUMMERTIME LEVELS. THROUGH MIDWEEK, TRADES WILL FURTHER EASE AS
TROPICAL STORM GENEVIEVE WEAKENS TO A POST-TROPICAL DEPRESSION AND
TRACKS FAR NORTHEAST OF THE STATE, DISRUPTING TRADE WIND FLOW.
BANDS OF MOISTURE WILL MOVE OVER THE STATE, RETURNING TYPICAL
SCATTERED SHOWERS TO WINDWARD AND MAUKA SLOPES. MODEL GUIDANCE
CONTINUE TO SHOW A TROPICAL UPPER LEVEL TROUGH SHIFTING JUST
NORTHWEST OF KAUAI BY THE MIDDLE OF THE WEEK. IN ADDITION AN AREA
OF ENHANCED MOISTURE MAY MOVE FROM EAST TO WEST ACROSS THE STATE.
IF THIS COMES TO FRUITION, EXPECT A STEADY INCREASE IN LOW TO
UPPER LEVEL MOISTURE/CLOUDS AND INCREASING CHANCES MODERATE TO
LOCALLY HEAVY WINDWARD AND MAUKA SHOWERS, ESPECIALLY FOR THE
WESTERN HALF OF THE STATE.
AVIATION
BREEZY TO WINDY TRADE WINDS WILL PREVAIL THROUGH EARLY SUNDAY.
OCCASIONAL MVFR CEILINGS AND VISIBILITIES WILL OCCUR WITHIN SHRA
MAINLY ACROSS NORTH THROUGH EAST SECTIONS OF THE ISLANDS AND IN
MOUNTAIN AREAS. OTHERWISE, VFR FLIGHT CONDITIONS WILL PREVAIL FOR
MOST LOCATIONS.
AIRMET TANGO FOR MODERATE LOW-LEVEL TURBULENCE OVER AND
IMMEDIATELY S THROUGH W OF MOUNTAINOUS TERRAIN OF ALL HAWAIIAN
ISLANDS REMAINS IN EFFECT TODAY DUE TO THE STRONG TRADE WINDS.
THIS AIRMET IS LIKELY TO REMAIN IN EFFECT AT LEAST INTO THE
EVENING HOURS TODAY.
MARINE
STRONG SURFACE HIGH PRESSURE NORTH OF THE STATE WILL MAINTAIN
STRONG TO NEAR GALE EASTERLY TRADE WINDS ACROSS ALL COASTAL
WATERS TODAY. THE SMALL CRAFT ADVISORY (SCA) IS IN EFFECT FOR ALL
COASTAL ZONES THROUGH TONIGHT FOR WINDS AND ALSO SEAS POTENTIALLY
EXCEEDING 10 FEET. WINDS WILL BEGIN TO TREND DOWN SUNDAY AS THE
SCA WILL LIKELY BE TRIMMED BACK TO THE WINDIER WATERS AND CHANNELS
AROUND MAUI COUNTY AND THE BIG ISLAND. THE COMBINATION OF A
STRONG MID- LATITUDE TROUGH AND TROPICAL STORM GENEVIEVE PASSING
FAR NORTHEAST OF THE ISLANDS INDUCES A WEAKNESS IN THE RIDGE WHICH
WILL THEN KEEP TRADE WINDS MORE MODERATE TO LOCALLY FRESH FOR THE
FIRST HALF OF THE WEEK.
SURF ALONG SOUTH FACING SHORES WILL STAY BELOW SEASONAL AVERAGES
AS CONSECUTIVE SMALL SOUTH TO SOUTHWEST MEDIUM PERIOD SWELLS
IMPACT THE SHORELINES THROUGH THE MIDDLE OF NEXT WEEK.
EAST FACING SHORES WILL REMAIN ROUGH AND CHOPPY THROUGH TONIGHT
DUE TO A COMBINATION OF STRONG TRADE WINDS AND A SMALL, MEDIUM
PERIOD EASTERLY SWELL GENERATED FROM TROPICAL STORM GENEVIEVE. BY
EARLY NEXT WEEK AS TRADE WINDS GRADUALLY WEAKEN, SURF WILL ALSO
DECLINE SLIGHTLY.
SURF ALONG NORTH FACING SHORES WILL REMAIN FLAT TO TINY EXCEPT FOR
AREAS EXPOSED TO THE EASTERLY TRADE WRAP.
FIRE WEATHER
WINDY TRADES WILL CONTINUE ACROSS THE STATE WITH SOME LOCATIONS
UNDER A WIND ADVISORY THOUGH THIS AFTERNOON. A DRIER AND MORE
STABLE AIRMASS WITH INVERSION HEIGHTS AROUND 5,000 TO 6,000 FT,
WILL CREATE GUSTY DOWNSLOPE WINDS AND LOWER RH VALUES. ANY
SHOWERS WILL MOSTLY BE LIMITED TO WINDWARD LOCATIONS. WHILE THE
KBDI WILL REMAIN BELOW THE CRITICAL THRESHOLDS, THIS WARM ,DRY AND
WINDY PATTERN WILL MAINTAIN NEAR CRITICAL FIRE WEATHER CONCERNS
THROUGH THIS AFTERNOON, ESPECIALLY FOR AREAS ABOVE THE INVERSION
HEIGHTS AND DOWNSLOPE OF RIDGES. TRADES ARE EXPECTED TO DECREASE
TO MORE NORMAL MODERATE TO LOCALLY BREEZY LEVELS SUNDAY INTO EARLY
NEXT WEEK. A STEADY INCREASE IN LOW TO UPPER LEVEL MOISTURE ALSO
FILL IN ACROSS THE STATE NEXT WEEK.
HFO WATCHES/WARNINGS/ADVISORIES
WIND ADVISORY UNTIL 6 PM HST THIS EVENING FOR WAIANAE MOUNTAINS-
LANAI MAUKA-KAHOOLAWE-MAUI LEEWARD WEST-KOHALA-BIG ISLAND
INTERIOR-KAUAI SOUTH-KOOLAU LEEWARD-MOLOKAI NORTH-MOLOKAI WEST-
MOLOKAI LEEWARD SOUTH-LANAI WINDWARD-LANAI LEEWARD-MAUI CENTRAL
VALLEY NORTH-MAUI CENTRAL VALLEY SOUTH-SOUTH HALEAKALA-BIG
ISLAND SOUTH-BIG ISLAND SOUTHEAST-BIG ISLAND NORTH.
SMALL CRAFT ADVISORY UNTIL 6 AM HST SUNDAY FOR ALL HAWAIIAN
WATERS-
DISCUSSION/FIRE WEATHER...TSAMOUS
AVIATION...VAUGHAN
MARINE...SHIGESATO
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