Area Forecast Discussion
Issued by NWS Honolulu, HI

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FXHW60 PHFO 260158
AFDHFO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HONOLULU HI
358 PM HST SAT APR 25 2015

.SYNOPSIS...
A SLOW-MOVING FRONT JUST WEST OF KAUAI THIS AFTERNOON WILL MOVE
OVER KAUAI THIS EVENING...THEN OAHU ON SUNDAY AND MAUI COUNTY ON
MONDAY. A STRONG HIGH FOLLOWING THE FRONT WILL SETTLE NORTH OF
KAUAI MONDAY AND BRING IN BREEZY TRADE WINDS TO THE ISLANDS LASTING
THROUGH AT LEAST WEDNESDAY. CLOUDS AND SHOWERS WILL FAVOR THE
WINDWARD AND MOUNTAIN AREAS NEXT WEEK.

&&

.DISCUSSION...
VISIBLE SATELLITE SHOWS A WEAK COLD FRONT JUST WEST OF KAUAI THIS
AFTERNOON MOVING VERY SLOWLY EASTWARD. BROKEN LOW TO MIDLEVEL
CLOUDS WITH SCATTERED SHOWERS ASSOCIATED WITH THE FRONT ARE
IMPACTING KAUAI AND NIIHAU. A FEW PRE-FRONTAL CLOUDS AND SHOWERS
COULD STILL IMPACT OAHU AND MAUI COUNTY INTO THE EARLY EVENING...BUT
THEY SHOULD DISSIPATE AROUND SUNSET. AFTERNOON SOUNDINGS SHOWED A
STABLE ENVIRONMENT AT HILO WITH AN INVERSION AT AROUND 8000 FEET
WITH A NORMAL 1.19 INCHES OF PRECIPITABLE WATER /PW/. NOT
SURPRISINGLY...THE ATMOSPHERE IS A BIT MORE MOIST AND UNSTABLE AT
LIHUE WITH A NEARLY ABSENT LOW LEVEL INVERSION AND A PW VALUE OF
1.79 INCHES.

THE FRONT ORIGINATES FROM A COMPACT LOW PRESSURE SYSTEM CURRENTLY
575 MILES TO THE NORTH OF HONOLULU. THIS LOW IS TRACKING TOWARDS
THE EAST AND IS NOT EXPECTED TO BE A IMPACT TO HAWAII.
HOWEVER...AS THE LOW LIFTS AWAY...THE FRONT WILL LINGER ACROSS
THE ISLANDS INTO MONDAY. THE FRONT IS EXPECTED TO REACH KAUAI
EARLY THIS EVENING...FOLLOWED BY OAHU SUNDAY MORNING...THEN STALL
AND DISSIPATE OVER MAUI COUNTY ON MONDAY. THE HIGHEST CHANCES FOR
RAIN IS EXPECTED ALONG THE FRONT.

WITHOUT MUCH UPPER LEVEL SUPPORT...NOT ANTICIPATING THUNDERSTORMS
WITH THIS SYSTEM. HOWEVER...WE COULD SEE SOME BOUTS OF HEAVY
SHOWERS ACROSS KAUAI TONIGHT...AND POSSIBLY ON SUNDAY FOR OAHU AND
MAUI COUNTY AS THE MOIST SOUTHERLY FLOW PUSHES FRONTAL AND
TROPICAL MOISTURE ONTO THE ISLANDS. VOGGY AND HUMID CONDITIONS
WILL ALSO CONTINUE THROUGH SUNDAY NIGHT.

A STRONG HIGH PRESSURE SYSTEM TO THE NORTHWEST WILL BUILD BEHIND
THE FRONT BEGINNING SUNDAY NIGHT. THE HIGH WILL PUSH BREEZY TRADE
WINDS FROM WEST TO EAST ACROSS THE ISLAND CHAIN ON MONDAY THROUGH
TUESDAY MORNING. WITH MUCH OF THE MOISTURE ASSOCIATED WITH THE FRONT
HUNG UP OVER THE SMALLER ISLANDS...EXPECT THE TRADE WINDS TO FOCUS
SHOWERS BACK ONTO THE AREA FOR MUCH OF NEXT WEEK. WINDWARD AND
MAUKA AREAS WILL BE PRIMARILY AFFECTED...BUT SHOWERS WILL BE LIGHT.

&&

.AVIATION...
AN APPROACHING COLD FRONT WILL MOVE THROUGH KAUAI TONIGHT AND OAHU
ON SUNDAY. MVFR CIGS AND SCATTERED SHRA WILL BECOME INCREASINGLY
LIKELY ALONG AND AHEAD OF THE COLD FRONT AS IT PUSHES SLOWLY
EASTWARD. THE REDUCED CIGS/VSBYS ARE EXPECTED TO AFFECT KAUAI
THROUGH THE OVERNIGHT HOURS...AND OAHU MOLOKAI LANAI AND WESTERN
SECTIONS OF MAUI FROM LATE TONIGHT THROUGH MUCH OF THE DAY ON
SUNDAY. ELSEWHERE...PREDOMINANTLY VFR CONDITIONS SHOULD PREVAIL.

AIRMET SIERRA REMAINS IN EFFECT FOR MOUNTAIN OBSCURATION ACROSS
KAUAI...AND THESE CONDITIONS WILL LIKELY CONTINUE THROUGH TONIGHT.
ADDITIONAL AIRMETS FOR MOUNTAIN OBSCURATION MAY BECOME NECESSARY
ACROSS OAHU AND MAUI COUNTY LATER TONIGHT.


&&

.MARINE...
SURF ALONG SOUTH AND EAST FACING SHORES WILL SUBSIDE THROUGH THE
REST OF THE WEEKEND AS THE WINDS AND SOUTH SOUTHWEST SWELL TAPER
OFF. A LARGER NORTH NORTHWEST SWELL IS SET TO ARRIVE SUNDAY NIGHT
THEN SHIFT FROM THE BY NORTH MONDAY NIGHT. THIS SWELL WILL LIKELY
PRODUCE SURF ABOVE THE ADVISORY THRESHOLD ALONG NORTH FACING
SHORES BY MONDAY...AND WILL LIKELY RISE TO ADVISORY LEVELS ALONG
EAST FACING SHORES LATE MONDAY OR TUESDAY AS THE SWELL DIRECTION
SHIFTS MORE NORTHERLY.

SOUTH TO SOUTHEAST WINDS HAVE WEAKENED BELOW SMALL CRAFT ADVISORY
/SCA/ CONDITIONS AND IS EXPECTED TO STAY BELOW CRITERIA THROUGH
SUNDAY. THEREFORE...THE SCA IS CANCELLED. STRONG NORTHEAST WINDS
BEHIND THE FRONT WILL SPREAD DOWN THE ISLAND CHAIN FROM KAUAI TO
THE BIG ISLAND FROM SUNDAY NIGHT THROUGH MONDAY NIGHT. SCA
CONDITIONS WILL LIKELY RETURN FOR SOME OF THE COASTAL ZONES AS THE
WINDS STRENGTHEN.

&&

.HFO WATCHES/WARNINGS/ADVISORIES...
NONE.

&&

$$

DISCUSSION/MARINE...FOSTER
AVIATION...JELSEMA




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