051
FXHW60 PHFO 091413
AFDHFO
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HONOLULU HI
400 AM HST SUN AUG 9 2026
SYNOPSIS
LIGHT AND BREEZY TRADES WITH LIGHT SHOWERS PRIMARILY OCCURRING
ALONG WINDWARD EXPOSURES AND HIGHER TERRAIN. A PLUME OF MOISTURE
MOVING SOUTH OF THE ISLANDS WILL INCREASE RAIN CHANCES OVER THE
EASTERN END OF THE STATE THROUGH MONDAY, FOLLOWED BY DRIER MID
WEEK CONDITIONS. BREWING DISTURBANCES WITHIN THE EASTERN PACIFIC
WILL NEED TO BE MONITORED FOR TROPICAL CYCLONE DEVELOPMENT THE
NEXT FEW DAYS.
DISCUSSION
AN UPPER RIDGE CENTERED NORTHEAST OF THE ISLANDS HAS ITS AXIS
DRAPED SOUTHWEST OVER THE REGION. THIS FEATURE HAS PROVIDED
ENOUGH STABILITY, AS EVIDENCED BY THE UPSTREAM STRATIFORM CLOUDS,
TO MAINTAIN PARTLY CLOUDY AND RELATIVELY DRY CONDITIONS TODAY.
UPPER RIDGING WILL GENTLY BACK OFF THE NEXT COUPLE OF DAYS WITH
THE RESULT BEING A DEEPER, MORE MOIST RESIDENT BOUNDARY LAYER.
THIS WILL ASSIST IN PRODUCING GREATER CLOUDS AND MORE WIDESPREAD
RAIN CAUGHT UP WITHIN MODERATE TRADE FLOW, ESPECIALLY FOR THE
WINDWARD COMMUNITIES OF BIG ISLAND AND MAUI. AN AREA OF HIGHER
MOISTURE SOUTHEAST OF BIG ISLAND WILL PASS ACROSS THE EASTERN HALF
OF THE STATE THROUGH EARLY MONDAY. THIS MORE MOIST AIR MASS WILL
PRIMARILY IMPACT BIG ISLAND BUT MAY CLIP MAUI COUNTY AND OAHU
THROUGH EARLY MONDAY. THIS WILL LIKELY BE THE CAUSE FOR MORE
FREQUENT, MAINLY WINDWARD AND UPSLOPE MAUKA, SHOWERS TODAY AND
TOMORROW. LOCALLY HEAVY RAINFALL IS ALSO POSSIBLE ON BIG ISLAND
AND WINDWARD MAUI THROUGH MONDAY MORNING. IF ENOUGH EARLY DAY SUN
HEATS UP MAUNA KEA AND MAUNA LOA'S (PRIMARILY WESTERN) SLOPES, IN
TANDEM WITH THIS HIGHER MOISTURE FLUX FROM THE SOUTH, THERE IS A
NON-ZERO CHANCE FOR AN ISOLATED THUNDERSTORM OR TWO TO DEVELOP
THIS AFTERNOON. DESPITE INCREASED CLOUD COVER, THE DAY WILL STILL
WARM UP IN THE STATEWIDE AVERAGE MIDDLE TO UPPER 80S. TRADES WILL
BE WELCOME WITH MANY COASTAL, LOW LYING SPOTS EXPERIENCING THE
MUGGINESS AS DEW POINTS REMAIN IN THE LOW 70S.
ONCE THIS SLUG OF SOUTHERN MOISTURE ADVECTS WEST SOUTHWEST OF THE
AREA TUESDAY, A DRIER AIR MASS WILL BRIEFLY PASS THROUGH DURING THE
MIDDLE OF THE WEEK. CLEARER SKIES AND LIMITED SHOWER ACTIVITY
WITH BREEZY TRADES NOT UNDERGOING MUCH CHANGE TUESDAY THROUGH
THURSDAY.
THERE ARE INCREASING PROBABILITIES THAT AN EASTERLY WAVE LOCATED
ABOUT 1,000 MILES EAST-SOUTHEAST OF THE ISLANDS WILL DEVELOP A
LOW CENTER AND STRENGTHEN INTO TROPICAL CYCLONE BY MID WEEK. THE NHC
HAS ASSIGMED A 90 PERCENT PROBABILITY OF TROPICAL CYCLONE
DEVELOPMENT OVER THE NEXT SEVEN DAYS. THE MAJORITY OF THE NWP
GUIDANCE, FROM DETERMINISTIC TO AI ENSEMBLES, STILL TRACK A TROPICAL
CYCLONE TOWARD THE STATE LATER THIS WEEK. WHILE STILL TOO EARLY TO
DEFINITIVELY DISCUSS THE DETAILS OF A POTENTIAL TROPICAL CYCLONE
IMPACTING HAWAII, THIS ACTIVE AREA WILL WARRANT CLOSE MONITORING THE
NEXT FEW DAYS. PLEASE REFER TO THE LATEST NHC FORECASTS CONCERNING
THIS POTENTIAL DEVELOPMENT AND EVOLUTION. IF NOT ALREADY FINALIZED,
NOW IS THE TIME TO BEGIN FINISHING UP YOUR HURRICANE PLAN(S) AND BE
READY TO EXECUTE THE PLAN WHEN THE TIME COMES.
AVIATION
MODERATE TO FRESH TRADES EXPECTED FOR THE NEXT SEVERAL DAYS. LOW
CIGS AND SHRA SHOULD MAINLY IMPACT WINDWARD AND MAUKA SPOTS. MVFR
CONDS LIKELY IN HEAVIER SHRA, OTHERWISE VFR PREVAILS.
AIRMET SIERRA IS IN EFFECT FOR MTN OBSC FOR WINDWARD LOCATIONS OF
ALL ISLANDS.
AIRMET TANGO IS IN EFFECT FOR MOD TURB DOWNWIND OF ISLAND
TERRAIN. THIS AIRMET WILL LIKELY BE NEEDED FOR NEXT SEVERAL DAYS.
MARINE
FRESH TO LOCALLY STRONG TRADE WINDS WILL PERSIST THROUGH AT LEAST
WEDNESDAY AS HIGH PRESSURE REMAINS ANCHORED NORTHEAST OF THE
STATE. A SMALL CRAFT ADVISORY (SCA) HAS BEEN EXTENDED FOR THE
TYPICAL WINDY CHANNELS AND WATERS AROUND MAUI COUNTY AND THE BIG
ISLAND THROUGH MONDAY AFTERNOON. BORDERLINE CONDITIONS WILL LIKELY
CONTINUE THROUGH AT LEAST WEDNESDAY, WHICH MAY PROMPT FURTHER
EXTENSIONS OF THE SCA. LATER IN THE WEEK, THE FOCUS WILL SHIFT TO
THE DEEP TROPICS SOUTHEAST OF THE STATE. A TROPICAL CYCLONE IS
LIKELY TO DEVELOP OVER THE NEXT FEW DAYS AND HAVE AN EFFECT ON
LOCAL WINDS, SEAS AND WEATHER AS EARLY AS THURSDAY.
CONTINUED SMALL OVERLAPPING SOUTH-SOUTHWEST SWELLS WILL PRODUCE
SOUTH SHORE SURF NEAR AUGUST AVERAGE THROUGH MONDAY AND NEAR TO ABOVE
AVERAGE SURF ON TUESDAY. A LARGER SWELL WILL ARRIVE TUESDAY NIGHT AND
MAY PUSH SURF TO THE HIGH SURF ADVISORY LEVEL LATE WEDNESDAY THROUGH
FRIDAY. THIS SWELL SHOULD SLOWLY DECREASE NEXT WEEKEND.
ALONG EAST-FACING SHORES, SHORT-PERIOD TRADE WIND SWELL WILL
GENERATE SURF JUST BELOW AUGUST AVERAGE THROUGH THURSDAY.
AN INCREASE IN SOUTHEAST SWELL IS POSSIBLE FRIDAY AND NEXT WEEKEND
GENERATED BY A TROPICAL CYCLONE THAT IS LIKELY TO DEVELOP SOUTHEAST
OF THE ISLANDS OVER THE NEXT FEW DAYS. ASIDE FROM WRAPPING TRADE WIND
ENERGY, SURF ALONG NORTH-FACING SHORES WILL REMAIN FLAT TO TINY
THROUGH THE WEEK.
DUE TO A COMBINATION OF PEAK MONTHLY HIGH TIDES AND WATER LEVELS
RUNNING HIGHER THAN PREDICTED IN A FEW LOCATIONS, A COASTAL FLOOD
STATEMENT IS IN EFFECT FOR MINOR COASTAL FLOODING POSSIBLE
AROUND THE AFTERNOON HIGH TIDE THROUGH AT LEAST TUESDAY. TIDES
WILL BE DECREASING ON WEDNESDAY, BUT COASTAL FLOODING MAY CONTINUE
TO BE POSSIBLE AROUND HIGH TIDE FOR LOCATIONS WHERE WATER LEVELS
ARE RUNNING HIGHEST.
FIRE WEATHER
MODERATE FIRE WEATHER CONDITIONS ARE EXPECTED FOR KAUAI AND OAHU
TODAY UNDER LIGHT TO BREEZY TRADE WINDS AND TYPICAL SUMMERTIME
SHOWER BEHAVIOR. FIRE WEATHER CONCERNS WILL BE LOWER OVER THOSE
AREAS IN MAUI COUNTY AND BIG ISLAND THAT RECEIVE HIGHER RAIN
AMOUNTS THROUGH MONDAY MORNING.
HFO WATCHES/WARNINGS/ADVISORIES
SMALL CRAFT ADVISORY UNTIL 6 PM HST MONDAY FOR ALENUIHAHA
CHANNEL-BIG ISLAND LEEWARD WATERS-BIG ISLAND SOUTHEAST WATERS-
MAALAEA BAY-PAILOLO CHANNEL.
DISCUSSION...BLOOD
AVIATION...WALSH
MARINE...QUESADA
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