High Surf in Hawaii, April 13 to 16, 2014

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HONOLULU HI
400 AM HST SUN APR 13 2014

.SYNOPSIS...
INCREASING TRADE WINDS ARE DUE TO A STRONG HIGH PRESSURE SYSTEM
PASSING NORTH OF THE STATE. CLOUDS AND SHOWERS WILL FAVOR WINDWARD
AND MAUKA AREAS WITH THE TRADE WINDS SUFFICIENTLY STRONG ENOUGH TO
BLOW SOME SHOWERS OVER TO LEEWARD AREAS AT TIMES. DRIER AND LESS
BREEZY WEATHER IS EXPECTED FOR THE SECOND HALF OF THE WEEK AS THE
HIGH MOVES AWAY FROM THE ISLANDS AND STARTS TO WEAKEN.

&&

.DISCUSSION...
WINDS CONTINUED ABOVE ADVISORY LEVELS FOR LANAI OVERNIGHT...WITH
PORTIONS OF THE KOHALA AREA ON THE BIG ISLAND ABOVE FROM TIME TO
TIME. BACKED BY AN ASCAT PASS AROUND 9 PM SHOWING STRONG WINDS OVER
THE WATER...A WIND ADVISORY CONTINUES FOR LANAI...KAHOOLAWE AND THE
KOHALA AREA OF THE BIG ISLAND. WINDS ARE ON THE INCREASE NEAR SOUTH
POINT...SO HAVE ADDED THAT REGION TO THE WIND ADVISORY THIS MORNING.

WINDS OVER SOME OF THE HIGHER PORTIONS OF OAHU ARE APPROACHING
ADVISORY LEVELS...BUT HAVE LEFT THEM OUT OF THE ADVISORY AT THIS
TIME. WILL BE MONITORING THE SITUATION AS THE DAY WEARS ON.

THE INCREASE IN TRADE WINDS IS DUE TO A HIGH PRESSURE SYSTEM PASSING
TO THE NORTH OF THE MAIN HAWAIIAN ISLANDS. THIS HIGH WILL BE THE
DRIVING FORCE FOR OUR WEATHER FOR MUCH OF THE WEEK. THE MODELS ARE
IN GOOD AGREEMENT WITH THE STRENGTHENING THROUGH MONDAY AS IT EDGES
TO THE NORTHEAST. BEYOND MONDAY...THE HIGH LIFTS TO THE NORTHEAST
AND STARTS A SLOW WEAKENING TREND. THE COMBINATION OF A WEAKENING
SYSTEM AND MOVING AWAY FROM THE ISLANDS SHOULD RESULT IN A DECLINE
IN WINDS MONDAY NIGHT AND TUESDAY.

SHOWERS PERSISTED OVER MAINLY WINDWARD AREAS OF MAUI COUNTY AND THE
BIG ISLAND OVERNIGHT. THE PUU KUKUI GAGE ON MAUI RECEIVED BY FAR THE
MOST RAINFALL WITH 2.49 INCHES BETWEEN 8 PM AND 2 AM. UNDER AN INCH
WAS RECEIVED AT THE REMAINING GAGES ON MAUI COUNTY AND THE BIG
ISLAND. THE MIMIC TOTAL PRECIPITABLE WATER /PW/ SHOWED AN INCREASE
IN MOISTURE IN THIS AREA OVERNIGHT...AND THE CURRENT MIMIC DATA
CONTINUES TO SHOW ELEVATED PW UPSTREAM OF THESE AREAS. AS
SUCH...EXPECT SHOWERS TO CONTINUE OVER THE NEXT COUPLE OF
HOURS...BUT THEN START TO TAPER OFF THIS AFTERNOON.

AN UPPER LEVEL TROUGH DIGGING DOWN FROM THE NORTHWEST HAS HELPED TO
ENHANCE THE SHOWERS MENTIONED ABOVE. THE TROUGH IS EXPECTED TO SET
UP TO THE SOUTHEAST OF THE ISLANDS TOMORROW...AND DEVELOP AN UPPER
LEVEL LOW NEAR 26N 145W MONDAY NIGHT. THIS SYSTEM WILL LIKELY
CONTINUE TO ENHANCE SHOWER ACTIVITY INTO THE MIDDLE OF THE WEEK.

BY THE MIDDLE OF THE WEEK...THE HIGH PRESSURE SYSTEM WILL BE MOVING
FURTHER FROM THE ISLANDS...ALLOWING TRADES TO SETTLE DOWN SOME...SO
EXPECT THE SECOND HALF OF THE UPCOMING WEEK TO BE LESS WINDY AND
DRIER.

&&

.AVIATION...
AIRMET TANGO REMAINS IN EFFECT FOR STRONG SFC WINDS OF 30 KT OR
GREATER ACROSS LANAI...AS WELL AS FOR MODERATE TURB OVER AND SOUTH
THROUGH WEST OF THE MOUNTAINS FOR ALL ISLANDS. THESE CONDITIONS ARE
LIKELY TO PERSIST THROUGH TODAY AS STRONG TRADES CONTINUE.

AIRMET SIERRA FOR TEMPO MTN OBSC IS IN EFFECT FOR MAUI COUNTY AND
WINDWARD SECTIONS OF THE BIG ISLAND DUE TO PERSISTENT SHOWERS AND
PERIODS OF MVFR CIGS. MTN OBSC IS LIKELY TO CONTINUE ACROSS THOSE
AREAS INTO THIS MORNING.

MAINLY VFR CONDITIONS SHOULD PREVAIL TODAY FOR MOST OTHER AREAS.
A DRIER AIRMASS IS FORECAST TO SPREAD INTO THE ISLANDS DURING THE
DAY WHICH SHOULD REDUCE SHOWER ACTIVITY SOMEWHAT THIS AFTERNOON.

&&

.MARINE...
DUE TO THE INCREASE IN TRADE WINDS...THE SMALL CRAFT ADVISORY IS NOW
IN EFFECT FOR ALL COASTAL WATERS. A HIGH SURF ADVISORY IS ALSO IN
EFFECT FOR EAST FACING SHORES DUE TO THE CHOPPY TRADE WIND SWELL.
WINDS ARE EXPECTED TO START TO DECREASE MONDAY NIGHT...SO EXPECT
BOTH ADVISORIES TO PERSIST AT LEAST THROUGH MONDAY.

A NEW NORTHWEST SWELL IS EXPECTED DURING THE WEDNESDAY THROUGH
FRIDAY TIME FRAME.

&&

.HFO WATCHES/WARNINGS/ADVISORIES...
HIGH SURF ADVISORY UNTIL 6 PM HST MONDAY FOR KAUAI WINDWARD-OAHU
KOOLAU-OLOMANA-MOLOKAI WINDWARD-MAUI WINDWARD WEST-WINDWARD
HALEAKALA-SOUTH BIG ISLAND-BIG ISLAND NORTH AND EAST.

SMALL CRAFT ADVISORY UNTIL 6 PM HST MONDAY FOR ALL COASTAL WATERS.

WIND ADVISORY UNTIL 6 PM HST MONDAY FOR LANAI MAKAI-LANAI
MAUKA-KAHOOLAWE-BIG ISLAND NORTH AND EAST-SOUTH BIG ISLAND-KOHALA-.

&&

SYNOPSIS/DISCUSSION/MARINE...M BALLARD
AVIATION...JACOBSON