Area Forecast Discussion
Issued by NWS Honolulu, HI

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000
FXHW60 PHFO 031937
AFDHFO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HONOLULU HI
1000 AM HST SUN MAY 3 2015

.SYNOPSIS...
MODERATE TRADE WINDS WILL PERSIST INTO MONDAY...WITH PERIODS OF
BREEZY TRADES EXPECTED DURING THE UPCOMING WORK WEEK. CONDITIONS
WILL BE STABLE...WITH CLOUDS AND SHOWERS FAVORING WINDWARD AND MAUKA
AREAS. POCKETS OF MOISTURE RIDING IN ON THE TRADE WINDS WILL
PERIODICALLY BOOST SHOWER COVERAGE...ALLOWING A FEW SHOWERS TO
SPREAD TO LEEWARD SECTIONS OF THE SMALLER ISLANDS.

&&

.DISCUSSION...
WATER VAPOR IMAGERY SHOWS A NEARLY ZONAL PATTERN OVER THE STATE. A
WEAK SHORTWAVE IS PASSING TO OUR NORTH AND THE SUBTROPICAL JET IS
WELL TO THE SOUTH. AT THE SURFACE...HIGH PRESSURE IS LOCATED FAR TO
THE NORTHEAST...WITH A RIDGE EXTENDING SEVERAL HUNDRED MILES TO OUR
NORTH. 12Z SOUNDINGS SHOW INVERSIONS RANGING FROM 7KFT AT LIHUE TO
10KFT AT HILO...WITH PRECIPITABLE WATERS ALSO 1.07 INCHES AND 1.32
INCHES RESPECTIVELY. EARLY MORNING MIMIC TOTAL PRECIPITABLE WATER
IMAGERY ALREADY SHOWS DRIER AIR MOVING OVER THE BIG ISLAND FROM THE
EAST...WITH POCKETS OF LOWER PW AIR NEAR/BELOW 1 INCH EXTENDING WELL
UPSTREAM TO THE NORTHEAST AND EAST OF THE STATE.

THE SURFACE HIGH NORTHEAST OF THE STATE IS BEING IMPINGED UPON BY A
FRONT FROM THE NORTH...CAUSING IT TO WEAKEN AND WINDS OVER STATE TO
DROP OFF A NOTCH. SURFACE PRESSURES AT AIRPORTS ACROSS THE ISLANDS
ARE ABOUT 1MB LOWER THAN THEY WERE 24 HOURS AGO. THE HIGH SHOULD
RESTRENGTHEN BRIEFLY EARLY NEXT WEEK AS THE FRONT DISSIPATES AND
UPPER LEVEL HEIGHTS AMPLIFY...CAUSING WINDS TO TURN LOCALLY BREEZY
ONCE AGAIN BY TUESDAY. A SECOND FRONT PUSHING INTO THE HIGH FROM THE
WEST DURING THE SECOND HALF OF THE WEEK WILL CAUSE IT WEAKEN AND
SHIFT EAST. THIS WILL LEAD TO ANOTHER SLIGHT DECREASE IN WINDS
DURING THE SECOND HALF OF THE WEEK. DURING THIS PERIOD...CLOUDS AND
SHOWERS WILL REMAIN MOSTLY CONFINED TO WINDWARD AND MAUKA AREAS.
POCKETS OF MOISTURE EMBEDDED IN THE TRADE FLOW WILL ENHANCE SHOWERS
AT TIME...WHICH WILL ALSO SPILL OVER TO LEEWARD AREAS AS WELL. SMALL
FEATURES LIKE THESE ARE DIFFICULT TO TIME...BUT ONE BAND MAY MOVE
THROUGH MONDAY NIGHT/TUESDAY.

AS THE CURRENT HIGH SHIFTS EASTWARD AND WEAKENS...A NEW HIGH WILL
BUILD IN NORTH OF THE STATE LATE IN THE WEEK. THIS NEW HIGH WILL
BRING ANOTHER SURGE IN WINDS DURING NEXT WEEKEND.

&&

.AVIATION...
HIGH PRESSURE NORTH OF THE STATE WILL KEEP A MODERATE E TO NE TRADE
WIND FLOW IN PLACE THROUGH TONIGHT...WITH CLOUDS AND SHOWERS FOCUSED
PRIMARILY ACROSS MOUNTAIN AND NORTH THRU EAST SECTIONS OF THE
ISLANDS. TEMPORARY MVFR CIGS MAY IMPACT PHTO THROUGH THE MORNING
HOURS. COULD ALSO SEE TEMPORARY MVFR CIGS AT PHNY FROM LATE THIS
MORNING THROUGH THE AFTERNOON. OVERNIGHT...MVFR CIGS MAY AFFECT PHTO
AND PHLI. ELSEWHERE...VFR CONDITIONS SHOULD PREVAIL.

AIRMET SIERRA REMAINS IN EFFECT FOR MOUNTAIN OBSCURATION ACROSS
PORTIONS OF MAUI AND THE BIG ISLAND. CONDITIONS ARE EXPECTED TO
IMPROVE LATER THIS MORNING.

AIRMET TANGO REMAINS IN EFFECT FOR LOW LEVEL TURBULENCE OVER AND TO
THE SOUTH THRU WEST OF THE MOUNTAINS. THESE CONDITIONS ARE EXPECTED
TO CONTINUE THROUGH THE REST OF THE DAY.

&&

.MARINE...
A SMALL CRAFT ADVISORY REMAINS IN EFFECT FOR THE TYPICALLY WINDIER
AREAS NEAR MAUI AND THE BIG ISLAND...AND WILL LIKELY BE NEEDED
THROUGH THE UPCOMING WEEK. THE ADVISORY MAY BE EXPANDED IN AREA
AROUND TUESDAY...AND AGAIN AROUND FRIDAY...WHEN TRADE WIND SPEEDS
ARE EXPECTED TO BE STRONGER.

MODERATE TO FRESH TRADE WINDS PREVAILING OVER AND UPWIND OF THE
STATE WILL MAINTAIN ELEVATED SHORT-PERIOD SURF ALONG EAST FACING
SHORES THROUGH THE WEEK. HOWEVER SURF IS EXPECTED TO REMAIN BELOW
ADVISORY LEVELS. A LONG PERIOD SOUTH-SOUTHWEST SWELL WILL GRADUALLY
BUILD ON TUESDAY AND PEAK WEDNESDAY INTO THURSDAY...LIKELY BRINGING
ADVISORY-LEVEL SURF TO SOUTH FACING SHORES. A TINY NORTH SWELL IS
EXPECTED MONDAY THROUGH WEDNESDAY...WITH A SLIGHTLY LARGER
NORTH-NORTHWEST SWELL FROM THURSDAY INTO SATURDAY.

&&

.HFO WATCHES/WARNINGS/ADVISORIES...
SMALL CRAFT ADVISORY UNTIL 6 PM HST TUESDAY FOR MAALAEA BAY... AND
THE PAILOLO AND ALENUIHAHA CHANNELS...AND WATERS SOUTH OF THE BIG
ISLAND.

&&

$$

PUBLIC/MARINE...BRAVENDER
AVIATION...JELSEMA





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