AFDHFO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HONOLULU HI
1001 AM HST THU JUL 7 2011

.SYNOPSIS...
FRESH TRADE WINDS ARE EXPECTED TO CONTINUE THROUGH THE END OF THE WEEK
DUE TO HIGH PRESSURE NORTH OF THE ISLANDS. A SLIGHT WEAKENING OF
THE WINDS IS EXPECTED THIS WEEKEND...BUT TRADES AND WINDWARD/MAUKA
SHOWERS WILL CONTINUE THROUGH THE FORECAST PERIOD. LARGE SURF WILL
CONTINUE ALONG SOUTH FACING SHORES.

&&

.DISCUSSION...
THE SUBTROPICAL HIGH IS LOCATED NORTH OF THE HAWAIIAN ISLANDS TODAY AND
IS DRIVING FRESH TRADE WINDS ACROSS THE AREA. THE HIGH IS NORTH OF
THE ISLANDS AND IS EXPECTED TO REMAIN NEARLY STATIONARY THROUGH SATURDAY
MORNING BEFORE DRIFTING SLIGHTLY TO THE NORTH LATE SATURDAY. ALOFT...MODELS
SHOW AN UPPER LEVEL DISTURBANCE MOVING TOWARDS THE STATE FROM THE
EAST THIS WEEKEND. THIS UPPER LEVEL FEATURE WILL HELP TO BREAK DOWN
THE DEEP TRADE WIND LAYER OVER THE ISLANDS AND RESULT IN A DECREASED
PRESSURE GRADIENT OVER THE ISLANDS. THE OVERALL RESULT WILL BE FRESH
TRADE WINDS CONTINUING TODAY AND FRIDAY WITH A SLOW AND GRADUAL
WEAKENING THROUGH THE WEEKEND DOWN TO MODERATE BY MONDAY. AS THE
TRADES CONTINUE...WILL GENERALLY SEE PASSING WINDWARD/MAUKA SHOWERS
THROUGH THE FORECAST PERIOD...WITH MOST OF THE SHOWERS OCCURRING
DURING THE NIGHTTIME AND EARLY MORNING HOURS. A FEW OF THESE SHOWERS
WILL MOVE ONTO LEEWARD SIDES AT TIMES.

THE PATH OF THE UPPER LEVEL LOW IS BROUGHT MUCH CLOSER TO THE STATE
BY THE ECMWF THAN THE GFS...BUT THERE IS GENERAL AGREEMENT WITH
THE SYSTEM LIFTING TO THE NORTH EARLY NEXT WEEK. AT THIS
TIME...THE ONLY REAL IMPACT EXPECTED IS PERHAPS AN INCREASE IN
TRADE WIND SHOWERS DURING THE SECOND HALF OF THE WEEKEND...AND
INTO NEXT WEEK.

&&

.AVIATION...
DUE TO STRONG TRADES...AIRMET TANGO WILL CONTINUE FOR LOW LEVEL
TURBULENCE FOR AREAS BELOW 080 S THRU W OF MOUNTAINS FOR THE MAIN
HAWAIIAN ISLANDS. ASSOCIATED TRADE SHOWERS WILL BRIEFLY LOWER
CEILINGS AND VISIBILITY TO MVFR CONDITIONS OVERNIGHT ON WINDWARD
TAF SITES. HOWEVER...VFR CONDITIONS WILL PREVAIL THROUGHOUT THE
FORECAST PERIOD.

&&

.MARINE...
FRESH TRADE WIND BACKGROUND FLOW WILL PRODUCE ACCELERATED WINDS
THROUGH THE HAWAIIAN CHANNELS. SMALL CRAFT ADVISORY /SCA/ CONDITIONS
WILL CONTINUE FOR TYPICAL WINDY AREAS AROUND MAUI COUNTY AND THE
BIG ISLAND WATERS. SCA LEVEL CONDITIONS ARE EXPECTED TO CONTINUE
OVER THE NEXT FEW DAYS.

A SOLID S-SSW WELL IS CURRENTLY IMPACTING SOUTH FACING SHORES OF
ALL ISLANDS AND A HIGH SURF ADVISORY IS IN EFFECT. ANOTHER SWELL
IS EXPECTED TO ARRIVE FRIDAY AND SATURDAY WHICH WILL KEEP ADVISORY
LEVEL SURF ALONG SOUTH FACING SHORES THROUGH SATURDAY.


&&

.HFO WATCHES/WARNINGS/ADVISORIES...
HIGH SURF ADVISORY UNTIL 6 PM HST SATURDAY FOR NIIHAU-KAUAI
WINDWARD-KAUAI LEEWARD-OAHU SOUTH SHORE-WAIANAE COAST-MOLOKAI
LEEWARD-LANAI MAKAI-KAHOOLAWE-MAUI LEEWARD WEST-MAUI CENTRAL
VALLEY-LEEWARD HALEAKALA-KONA-SOUTH BIG ISLAND-BIG ISLAND NORTH
AND EAST.

WIND ADVISORY UNTIL 6 AM HST FRIDAY FOR HALEAKALA SUMMIT-BIG
ISLAND SUMMITS.

SMALL CRAFT ADVISORY UNTIL 6 PM HST SATURDAY FOR KAIWI CHANNEL-
MAALAEA BAY-PAILOLO CHANNEL-ALENUIHAHA CHANNEL-BIG ISLAND
LEEWARD WATERS-BIG ISLAND SOUTHEAST WATERS.


&&

$$