Area Forecast Discussion
Issued by NWS Honolulu, HI

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
000
FXHW60 PHFO 040133
AFDHFO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HONOLULU HI
400 PM HST SUN MAY 3 2015

.SYNOPSIS...
BREEZY TRADE WINDS WILL PICK UP AGAIN ON MONDAY AND TUESDAY.
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
LOCATED TO THE SOUTH. AT THE SURFACE...HIGH PRESSURE IS LOCATED FAR
TO THE NORTHEAST...WITH A RIDGE EXTENDING SEVERAL HUNDRED MILES TO
OUR NORTH. 00Z SOUNDINGS SHOW INVERSIONS RANGING FROM 6KFT AT LIHUE
TO 9KFT AT HILO...WITH PRECIPITABLE WATERS ALSO RANGING FROM 0.8
INCHES TO 0.96 INCHES RESPECTIVELY. LATE MORNING MIMIC TOTAL
PRECIPITABLE WATER IMAGERY SHOWS A BAND OF MOISTURE NEAR MAUI
COUNTY...WITH DRIER AIR AT THE FLANKS OF THE STATE. ANOTHER BAND OF
MOISTURE OVER 100 MILES WIDE IS LOCATED JUST EAST OF THE BIG
ISLAND...WITH THE DRIER AIR FARTHER UPSTREAM TO THE NORTHEAST AND
EAST.

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 OVER THE NEXT COUPLE DAYS AS THE FRONT
DISSIPATES AND UPPER LEVEL HEIGHTS AMPLIFY...CAUSING WINDS TO TURN
LOCALLY BREEZY ONCE AGAIN ON MONDAY AND 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 NORTHEAST OF THE STATE WILL KEEP A MODERATE E TO NE
TRADE WIND FLOW IN PLACE THROUGH MONDAY...WITH CLOUDS AND SHOWERS
FOCUSED PRIMARILY ACROSS MOUNTAIN AND NORTH THRU EAST SECTIONS OF
THE ISLANDS. TEMPORARY MVFR CIGS MAY AFFECT PHNY THROUGH EARLY THIS
EVENING...AND PHTO AND PHLI OVERNIGHT. ELSEWHERE...VFR CONDITIONS
SHOULD PREVAIL.

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 TUESDAY.

AIRMET SIERRA FOR MOUNTAIN OBSCURATION MAY BE NECESSARY LATER
TONIGHT ACROSS NORTH THRU EAST SECTIONS OF SOME OF THE ISLANDS.

&&

.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 BY
TUESDAY...AND AGAIN FRIDAY INTO SATURDAY...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-PAILOLO
CHANNEL-ALENUIHAHA CHANNEL-BIG ISLAND LEEWARD WATERS-BIG ISLAND
SOUTHEAST WATERS.

&&

$$

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





USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.