Area Forecast Discussion
Issued by NWS Honolulu, HI

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000
FXHW60 PHFO 020640
AFDHFO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HONOLULU HI
840 PM HST WED OCT 1 2014

.SYNOPSIS...
LIGHT TRADE WINDS THURSDAY AND FRIDAY WILL YIELD TO LIGHT AND
VARIABLE WINDS OVER THE WEEKEND...AND INTO NEXT WEEK. THE LIGHT
TRADES WILL DELIVER A FEW SHOWERS TO WINDWARD COASTS AND SLOPES...
WHILE ALSO ALLOWING AFTERNOON CLOUDS AND SHOWERS TO DEVELOP OVER
INTERIOR AND LEEWARD AREAS. THE LIGHT AND VARIABLE WINDS WILL LEAD
TO CLEAR NIGHTS AND MORNINGS...AND CLOUDY AFTERNOONS AND EVENINGS...
WITH CLOUDS AND SHOWERS FAVORING INTERIOR AND UPSLOPE AREAS. A MORE
STABLE AIR MASS DEVELOPING OVER THE ISLANDS SHOULD LIMIT SHOWER
INTENSITY. MUGGY CONDITIONS WILL CONTINUE.

&&

.DISCUSSION...
HEAVY DOWNPOURS THAT AFFECTED PARTS OF THE STATE THIS AFTERNOON HAVE
ALL DISSIPATED...AND SKIES OVER THE ISLANDS ARE GENERALLY
CLEARING...ESPECIALLY OVER LEEWARD AREAS. LATEST SURFACE ANALYSIS
DEPICTS A SURFACE RIDGE JUST N OF KAUAI...EXTENDING SW FROM A HIGH
CENTERED ABOUT 1900 MILES NE OF THE ISLANDS. WITH THE RIDGE IN THIS
POSITION...A LIGHT E TO SE FLOW EXISTS IN THE LOW LEVELS OVER THE
ISLANDS...WITH ISLAND-SCALE LAND/SEA BREEZE CIRCULATIONS OVERRIDING
THIS FLOW...ESPECIALLY AT THE SURFACE. A LOW ALOFT IS CENTERED ABOUT
500 MILES ENE OF OAHU AND MOVING SLOWLY E...WITH AN ASSOCIATED
WEAK TROUGH EXTENDING W OVER THE STATE. HIGH CLOUDS S OF THE TROUGH
AXIS ARE STREAMING OVER THE BIG ISLAND AND ADJACENT WATERS.

OVERNIGHT...EXPECT SKIES TO BECOME GENERALLY CLEAR OVER LEEWARD
AREAS...WHILE THE LIGHT E/SE WINDS AT CLOUD LEVEL PUSH A FEW SHOWERS
OVER WINDWARD AREAS. RADAR SHOWS THAT SOME OF THESE SMALL SHOWERS
HAVE INTENSE CORES...MOST RECENTLY NOTED OVER WINDWARD KAUAI...
KAUAI LEEWARD WATERS...AND SW OF MAUI AND LANAI.

A SOMEWHAT LESS ACTIVE WEATHER PATTERN IS EXPECTED TO DEVELOP OVER
THE ISLANDS BY THURSDAY...AS A SLIGHTLY DRIER AIRMASS SPREADS IN
FROM THE E...AND MID LEVEL TEMPS WARM AS THE LOW ALOFT DEPARTS.
MODELS INDICATE THAT A WEAK TRADE WIND FLOW WILL DEVELOP THURSDAY
AND PERSIST THROUGH FRIDAY...AS THE RIDGE DRIFTS N SLIGHTLY. STILL
EXPECT AFTERNOON SEABREEZES THURSDAY AND FRIDAY AFTERNOON TO DRIVE
INTERIOR AND LEEWARD CLOUDS AND SHOWERS...BUT THE SHOWERS ARE NOT
EXPECTED TO AS WIDESPREAD OR INTENSE AS WE HAVE OBSERVED THE PAST
FEW DAYS. A HYBRID WEATHER PATTERN SEEMS LIKELY...WITH LIMITED
SHOWERS AND CLOUDS ACROSS WINDWARD AREAS DURING THE NIGHTS AND EARLY
MORNINGS...AND CLOUDS WITH SCATTERED SHOWERS ACROSS LEEWARD AND
INTERIOR IN THE AFTERNOONS. WARM AND MUGGY CONDITIONS WILL
CONTINUE...WITH ABOVE NORMAL SEA SURFACE TEMPERATURES SURROUNDING
THE ISLANDS CONTRIBUTING TO RATHER HIGH DEWPOINTS. HIGH CLOUDS NEAR
THE BIG ISLAND SHOULD CLEAR OUT BY THURSDAY AS THE TROUGH ALOFT
WEAKENS.

DURING THE WEEKEND AND INTO THE MIDDLE NEXT WEEK...A COLD FRONT
SEVERAL HUNDRED MILES NW OF THE STATE WILL MOVE SLOWLY SE...PUSHING
THE SURFACE RIDGE OVER THE STATE...SUPPORTING A PURE LAND/SEA
BREEZE PATTERN OVER THE ISLANDS. SCATTERED SHOWERS WILL DEVELOP
MAINLY ACROSS INTERIOR AND LEEWARD AREAS EACH AFTERNOON...WITH
CLEARING EACH NIGHT AS LAND BREEZES TAKE OVER. CONTINUED ABOVE
NORMAL DEWPOINTS AND THE LACK OF TRADE WINDS WILL MAINTAIN WARM AND
MUGGY CONDITIONS. DEVELOPING LIGHT SE BACKGROUND FLOW MAY ALLOW
AREAS OF VOLCANIC HAZE TO SPREAD OVER THE SMALLER ISLANDS DURING
THIS TIME. THE FRONT IS FORECAST TO RETREAT NORTHWARD BY THE MIDDLE
OF NEXT WEEK...ALLOWING THE RIDGE TO SHIFT N...AND A LIGHT TRADE
WIND FLOW IS EXPECTED TO RETURN.

&&

.AVIATION...
LIGHT BACKGROUND WIND FLOW WILL ALLOW LAND BREEZES OVER THE ISLANDS
TONIGHT. EXPECT DECREASING LOW CLOUD COVER AS A RESULT...WITH VFR
CONDITIONS PREVAILING. SEA BREEZES WILL PRODUCE LOW CLOUDS OVER THE
LEEWARD AND ISLAND INTERIOR SECTIONS BY THURSDAY AFTERNOON. MVFR
CIGS...ISOL OR TEMPO MTN OBSC WILL BE POSSIBLE AS THE CLOUD COVER
BUILDS THROUGH THE DAY. ON THURSDAY...THE ATMOSPHERE WILL BE A
LITTLE BIT MORE STABLE THAN THE PAST FEW DAYS...SO EXPECTING SHALLOW
OR MODERATE CLOUD TOPS AND LIGHTER ASSOCIATED SHOWERS THAN THE PAST
FEW DAYS.

&&

.MARINE...
SURF OBSERVATIONS AND BUOY DATA INDICATE THAT THE CURRENT S SWELL
REMAINS SUFFICIENTLY HIGH TO MAINTAIN ADVISORY LEVEL SURF ALONG S
FACING SHORES. THE ADVISORY CURRENTLY EXTENDS THROUGH THE DAY
THURSDAY...WITH SURF EXPECTED TO DECREASE BELOW ADVISORY LEVELS
THURSDAY EVENING. NO OTHER SIGNIFICANT S SWELLS ARE EXPECTED THROUGH
THE WEEKEND. A MODERATE NW SWELL APPEARS TO HAVE PEAKED EARLIER
TODAY...AND WILL GRADUALLY SUBSIDE THROUGH FRIDAY...JUST AS A NEW
MODERATE NW SWELL BEGINS TO BUILD. THIS SWELL IS EXPECTED TO PEAK
LATE SATURDAY AND DIMINISH INTO MONDAY...JUST AS ANOTHER SIMILARLY-
SIZED NW SWELL BEGINS TO ARRIVE. RESULTANT SURF IS EXPECTED TO
REMAIN BELOW ADVISORY LEVELS ALONG N AND W FACING SHORES. AFTER A
BIT OF A HIATUS...THE OAHU SURF DISCUSSION /SRDHFO/ WAS UPDATED
TODAY...AND CONTAINS DETAILS THAT CAN BE LOOSELY APPLIED STATEWIDE.

WINDS AND SEAS WILL REMAIN BELOW SMALL CRAFT ADVISORY LEVELS
THROUGH THE FORECAST PERIOD.

&&

.HFO WATCHES/WARNINGS/ADVISORIES...
HIGH SURF ADVISORY UNTIL 6 PM HST THURSDAY FOR SOUTH FACING SHORES
OF ALL ISLANDS.

&&

$$

DISCUSSION/MARINE...BIRCHARD
AVIATION...FOSTER




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