839
FXHW60 PHFO 121918
AFDHFO
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HONOLULU HI
918 AM HST SAT SEP 12 2026
SYNOPSIS
DRIER TRADE WINDS WILL PREVAIL INTO EARLY NEXT WEEK WITH LIGHT
SHOWERS ON THE WINDWARD SIDE OF THE ISLANDS. A WEAK DISTURBANCE
WILL LIFT OUT OF THE DEEP TROPICS TOWARDS THE MIDDLE OF NEXT WEEK
BRINGING A SLIGHT UPTICK IN TRADES, INCREASED HUMIDITY, AND A
BETTER CHANCE FOR SHOWERS.
SHORT TERM UPDATE
DRY AND STABLE TRADE WINDS EXPECTED THROUGH THE WEEKEND, WITH A
FEW SPOTTY AFTERNOON SHOWERS ACROSS LEEWARD BIG ISLAND. NO
UPDATES TO THE FORECAST FOR THIS MORNING.
PREV DISCUSSION
ISSUED AT 303 AM HST SAT SEP 12 2026
MORNING SATELLITE WATER VAPOR IMAGERY SHOWS A LARGE UPPER LEVEL
LOW WELL NORTHEAST OF THE STATE AND GENERALLY DRY NORTHWEST FLOW
ALOFT AS A WEAK SHORT WAVE MOVES SOUTHEAST OVER THE AREA. REMNANT
MOISTURE AND SHOWERS REMAIN WEST AND SOUTHWEST OF THE BIG ISLAND
AND WILL GRADUALLY DISSIPATE THROUGH THE MORNING.
DRIER AIR IN PREVAILING TRADE WINDS WILL CONTINUE THROUGH THE
WEEKEND. TYPICAL TRADES WEATHER IS EXPECTED OVER THE NEXT FEW
DAYS WITH OCCASIONAL LIGHT SHOWERS ACROSS THE WINDWARD SIDE OF THE
ISLANDS EACH DAY.
A TROPICAL DISTURBANCE CURRENTLY SEVERAL HUNDRED MILES SOUTHEAST
OF HILO WILL MOVE NORTHWESTWARD OVER THE NEXT SEVERAL DAYS. NHC
FORECAST HAS DROPPED TO A 10% CHANCE OF DEVELOPMENT INTO A
TROPICAL CYCLONE OVER THE NEXT 7 DAYS. MOST LIKELY SCENARIO IS FOR
THIS FEATURE TO HELP PULL TROPICAL MOISTURE INTO THE AREA, THOUGH
HOW MUCH AND WHEN WILL DEPEND ON ITS TRACK. FOR NOW EXPECT
PRECIPITABLE WATER AND DEW POINTS TO INCREASE ONCE AGAIN WITH A
SMALL INCREASE IN TRADE WINDS AND HIGHER PRECIPITATION CHANCES
TOWARDS THE MIDDLE OF NEXT WEEK.
TROPICAL STORM NORBERT IS CURRENTLY AROUND 1760 MILES ESE OF
HILO, MOVING WEST-NORTHWEST AT 10 MPH. THIS SYSTEM IS NOW
FORECAST TO REMAIN AT TROPICAL STORM STRENGTH THROUGH WEDNESDAY,
WHEN IT WILL STILL BE SOUTHEAST OF HAWAII. THERE REMAINS HIGHER
THAN NORMAL UNCERTAINTY ON WHERE THIS STORM WILL TRACK AS IT
APPROACHES, SO CONFIDENCE IN IMPACTS - IF ANY - TO THE ISLANDS
REMAINS LOW.
AVIATION
A LARGE UPPER LEVEL LOW CENTERED APPROXIMATELY 1,200 MILES
NORTHEAST OF THE ISLANDS IS WEAKENING THE PRESSURE GRADIENT AND
THEREFORE THE TRADE WINDS NEAR HAWAII. THESE WEAKER TRADES WILL
CONTINUE THROUGH THE WEEKEND. WINDS MAY BECOME LIGHT ENOUGH
WITHIN MORE WIND- PROTECTED LEEWARD AREAS TO INITIATE LOCAL
BREEZES. RELATIVELY DRY AIR IS WORKING ITS WAY IN ACROSS THE STATE
AND WILL LIMIT SHOWER ACTIVITY.
MARINE
MODERATE TO LOCALLY FRESH TRADES WILL CONTINUE THROUGH EARLY NEXT
WEEK BEFORE GRADUALLY STRENGTHENING THROUGH THE LATTER HALF OF THE
WEEK. MOISTURE ASSOCIATED WITH A TROUGH MOVING IN ON THE TRADE
WIND FLOW MAY BRING AN INCREASE OF SHOWERS TO THE COASTAL WATERS
TUESDAY INTO WEDNESDAY.
SURF ALONG SOUTH-FACING SHORES WILL GRADUALLY DECLINE THROUGH THE
WEEKEND AS THE SMALL, MEDIUM- TO LONG-PERIOD ENERGY SLOWLY FADES.
A MODERATE, LONG-PERIOD SWELL GENERATED BY A LOW THAT PASSED NEAR
AUSTRALIA AND NEW ZEALAND IS FORECAST TO ARRIVE MID TO LATE WEEK
NEXT WEEK.
SURF ALONG EAST-FACING SHORES WILL REMAIN SMALL TO MODERATE THROUGH
THE FORECAST PERIOD DUE TO THE MODERATE TO FRESH TRADE WINDS. FLAT TO
TINY SURF ALONG NORTH FACING SHORES IS EXPECTED THROUGH THE FORECAST
PERIOD.
FIRE WEATHER
ISSUED AT 303 AM HST SAT SEP 12 2026
FIRE WEATHER RISK WILL REMAIN LOW THE NEXT SEVERAL DAYS DUE LIGHT
TO MODERATE WINDS AND THE EFFECTS OF RECENT RAINFALL. INVERSION
HEIGHTS ARE EXPECTED TO REMAIN ELEVATED OR WEAK THROUGH MONDAY.
HFO WATCHES/WARNINGS/ADVISORIES
NONE.
SHORT TERM UPDATE...FOSTER
PREVIOUS DISCUSSION...SS
AVIATION...PARKER
MARINE...FARRIS
FIRE WEATHER...SS
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