906
FXHW60 PHFO 140111
AFDHFO
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HONOLULU HI
311 PM HST SUN APR 13 2025
SYNOPSIS
BREEZY TRADE WINDS WILL CONTINUE FOR THE NEXT COUPLE OF DAYS,
WITH PASSING CLOUDS AND SHOWERS FAVORING WINDWARD AND MAUKA AREAS.
LIGHTER WINDS ARE EXPECTED BY THE MIDDLE OF THE WEEK WITH FEWER
WINDWARD SHOWERS AND A GREATER CHANCE FOR AFTERNOON INTERIOR
SHOWERS EACH AFTERNOON.
DISCUSSION
THE DIURNAL TREND HAS TAKEN ITS TOLL ON THE BATCH OF MOISTURE THAT
WAS POSITIONED OVER MAUI COUNTY THIS MORNING. NOW FOCUSED OVER
OAHU, LITTLE REMAINS ASIDE FROM A FEW ISOLATED SHOWERS. SUSPECT
COVERAGE WILL BEGIN TO INCREASE AGAIN DURING THE NEXT FEW HOURS
BRINGING AN UPTICK IN SHOWERS TO WINDWARD OAHU AND, MORE LIKELY,
WINDWARD KAUAI BY LATE TONIGHT. WATER VAPOR AND MODEL ANALYSIS
INDICATES DIMINISHED STABILITY OVER THE WESTERN END OF THE STATE
ASSOCIATED WITH A WEAK UPPER LOW AND LEFT EXIT REGION OF THE
ATTENDANT 100KT UPPER JET. THIS IS CONTRIBUTING TO DIMINISHED
INSTABILITY FROM KAUAI THROUGH OAHU AS EVIDENCED BY STEEPENING
LAPSE RATES ON THIS AFTERNOON'S SOUNDING OUT OF KAUAI. AS SHOWERS
REDEVELOP TONIGHT, A FEW HEAVIER SHOWERS MAY DEVELOP IN THE
VICNITY OF KAUAI. OTHERWISE, THIS UPPER LOW WILL SLOWLY DRIFT
EASTWARD ACROSS THE STATE THROUGH TUESDAY CONTRIBUTING TO A SLOW
EASTWARD SPREADING OF WEAK INSTABILITY. UPSTREAM VISIBLE IMAGERY
SUGGESTS A STEADY SUPPLY OF SHALLOW MOISTURE WHICH WILL FAVOR
CONTINUED SHOWERS OVER WINDWARD AND MAUKA AREAS THROUGH EARLY THIS
WEEK. ANY PARTICULARLY ORGANIZED POCKETS OF MOISTURE MAY CONTAIN
LOCALLY HEAVY SHOWERS.
TUESDAY THROUGH AT LEAST EARLY WEDNESDAY WILL BE CHARACTERIZED BY
MID-LEVEL SHORTWAVE RIDGING DEVELOPING IN RESPONSE TO A DIGGING MID-
LATITUDE TROUGH THAT WILL IMPINGE ON THE AREA LATE WEDNESDAY THROUGH
FRIDAY. THIS PERIOD OF RIDGING WILL BRING A BRIEF PERIOD OF
INCREASED STABILITY AS THE SURFACE PRESSURE GRADIENT DIMINISHES. AS
A CONSEQUENCE, A TRANSITION TO A LAND AND SEA BREEZE PATTERN IS
ANTICIPATED NO LATER THAN WEDNESDAY AS MID-LEVEL STABILITY BEGINS TO
WEAKEN. LARGE SCALE ASCENT IS THEN MAXIMIZED THURSDAY THROUGH FRIDAY
AND AFTERNOON SHOWERS OVER ISLAND INTERIORS ARE LIKELY TO GAIN
APPRECIABLE DEPTH LIKELY RESULTING IN POCKETS OF HEAVY DOWNPOURS
EACH AFTERNOON. LIGHT WINDS CONTINUE INTO THE WEEKEND AS MID-LEVEL
FORCING DIMINISHES RESULTING IN EITHER A LAND/SEA BREEZE PATTERN
WITH MORE MUTED DIURNAL CONVECTION OR A HYBRID SEA BREEZE PATTERN
WHICH WILL TEND TO FOCUS SHOWERS OVER WESTERN SLOPES OF EACH
ISLAND.
AVIATION
BREEZY TRADE WINDS WILL CONTINUE THROUGH MONDAY. SCATTERED LOW
CLOUDS AND SHOWERS WILL TRACK IN WITH THE TRADE WIND FLOW, AND MOST
ACTIVE IN THE LATE NIGHT AND MORNING HOURS AND FAVOR WINDWARD
SLOPES AND COASTS.
AIRMET TANGO IS IN EFFECT FOR TEMPO MODERATE TURBULENCE BELOW
8000 FEET OVER LEEWARD SIDES OF ALL HAWAIIAN ISLANDS. AIRMET TANGO
IS ALSO POSTED FOR JET STREAM TURBULENCE OVER HAWAII BETWEEN
FL280 AND FL380.
MARINE
HIGH PRESSURE NORTHEAST OF THE STATE WILL MAINTAIN MODERATE TO
STRONG TRADES THROUGH MONDAY. AS A RESULT, A SMALL CRAFT ADVISORY
(SCA) REMAINS IN EFFECT FOR THE TYPICALLY WINDY WATERS AROUND MAUI
AND THE BIG ISLAND THROUGH 6 PM MONDAY. THE TRADES WILL GRADUALLY
EASE TUESDAY AND TUESDAY NIGHT, THEN BECOME FURTHER DISRUPTED
WEDNESDAY AND THURSDAY AS A FRONT APPROACHES THE STATE FROM THE
NORTHWEST. WINDS WILL BECOME LIGHT AND VARIABLE OVER THE WESTERN
WATERS AS A RESULT, WHILE WINDS OVER THE EASTERN HALF OF THE ISLAND
CHAIN SHIFT OUT OF THE EAST-SOUTHEAST AT LIGHT TO MODERATE SPEEDS.
EAST SHORE SURF WILL REMAIN AT OR JUST ABOVE AVERAGE THROUGH TUESDAY,
AND WILL BE RATHER ROUGH DUE TO THE STRONG TRADES, PARTICULARLY
THROUGH MONDAY. AS THE TRADES DIMINISH DURING THE SECOND HALF OF
THE WEEK, SURF ALONG EAST FACING SHORES WILL DROP BELOW NORMAL.
A SMALL TO MODERATE SIZED NORTHWEST SWELL WILL GIVE A BOOST TO
SURF ALONG NORTH AND WEST FACING SHORES MONDAY AND TUESDAY,
FOLLOWED BY A DECLINE WEDNESDAY AND THURSDAY. A NEW MODERATE-SIZED
NORTH-NORTHWEST SWELL WILL ARRIVE LATE THURSDAY, POTENTIALLY
BRINGING ADVISORY LEVEL SURF TO NORTH AND WEST FACING SHORES
FRIDAY, THEN LOWERING NEXT WEEKEND.
SURF ALONG SOUTH FACING SHORES WILL REMAIN SMALL AND MOSTLY AT
BACKGROUND LEVELS THROUGH LATE NEXT WEEK.
HFO WATCHES/WARNINGS/ADVISORIES
SMALL CRAFT ADVISORY UNTIL 6 PM HST MONDAY FOR MAALAEA BAY-
PAILOLO CHANNEL-ALENUIHAHA CHANNEL-BIG ISLAND LEEWARD WATERS-BIG
ISLAND SOUTHEAST WATERS.
DISCUSSION...JVC
AVIATION...FOSTER
MARINE...TS
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