Area Forecast Discussion
Issued by NWS Honolulu, HI

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615
FXHW60 PHFO 130939 AAA
AFDHFO

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE HONOLULU HI
1139 PM HST FRI FEB 12 2016

.UPDATE...
FORECASTS HAVE BEEN UPDATED TO DROP THE HIGH SURF ADVISORY FOR
NORTH FACING SHORES. ALSO INCREASED POPS AND SKY COVER FOR
WINDWARD OAHU...WHERE SHOWERS HAVE PERSISTED DURING THE EVENING
DUE TO A FAVORABLE EAST-SOUTHEAST FLOW PATTERN.

&&

.SYNOPSIS...
LOCALLY BREEZY EASTERLY TRADE WINDS WILL PERSIST THROUGH MOST OF
SUNDAY ACROSS MAUI COUNTY AND THE BIG ISLAND...WHILE GENTLE EAST-
SOUTHEAST WINDS ALLOW FOR LEEWARD LAND AND SEA BREEZES ON OAHU
AND KAUAI. STABLE CONDITIONS WILL FOCUS PASSING SHOWERS OVER
WINDWARD SLOPES...MAINLY ON MAUI AND THE BIG ISLAND. NORTHEASTERLY
TRADE WINDS WILL INCREASE EARLY NEXT WEEK AS STRONG HIGH PRESSURE
BUILDS NORTHWEST OF THE STATE. SHOWERS ARE EXPECTED TO INCREASE
OVER THE AREA AS FRONTAL REMNANTS ARE CARRIED ACROSS THE STATE
FROM MONDAY NIGHT THROUGH WEDNESDAY.

&&

.PREV DISCUSSION.../ISSUED 830 PM HST FRI FEB 12 2016/

SCATTERED SHOWERS EMBEDDED IN THE TRADE WIND FLOW ARE MOVING INTO
SOME WINDWARD AREAS OF THE BIG ISLAND...EAST MAUI AND MOLOKAI THIS
EVENING...AND SOME LIGHT SHOWERS HAVE RECENTLY DEVELOPED OVER THE
KOOLAU RANGE ON OAHU AS WELL. DRY WEATHER PREVAILS OVER THE
REMAINDER OF THE STATE. SURFACE ANALYSIS DEPICTS HIGH PRESSURE
CENTERED FAR TO THE NORTHEAST...WITH A RIDGE EXTENDING WESTWARD TO
THE NORTH OF THE ISLANDS...AND A COLD FRONT OVER THE NORTHWESTERN
HAWAIIAN ISLANDS ABOUT 800 MILES WEST-NORTHWEST OF KAUAI. THE
TRADE WINDS ARE STRONGEST OVER THE EASTERN HALF OF THE STATE...
WHILE WEAKER EAST-SOUTHEAST FLOW PREVAILS OVER THE WESTERN HALF.
A DRY AND STABLE AIRMASS REMAINS IN PLACE...WITH THE 00Z SOUNDINGS
MEASURING PWATS AROUND 0.9 INCHES AND STRONG INVERSIONS BASED
BETWEEN 6500 AND 8000 FEET. WATER VAPOR IMAGERY SHOWS A STRONG MID
LEVEL RIDGE CENTERED ALMOST DIRECTLY OVERHEAD. MIMIC-TPW IMAGERY
SHOWS SLIGHTLY HIGHER MOISTURE NEAR THE BIG ISLAND AND MAUI THAN
ELSEWHERE...BUT EVEN OVER THE EASTERN ISLANDS THE ESTIMATED PWATS
ARE BARELY ABOVE ONE INCH.

LITTLE CHANGE IS EXPECTED OVERNIGHT THROUGH THE WEEKEND. HIGH
PRESSURE WILL REMAIN FAR NORTHEAST OF THE STATE...DRIVING MODERATE
EASTERLY FLOW ACROSS THE BIG ISLAND AND MAUI COUNTY...VEERING TO
GENTLE EAST/SOUTHEAST FLOW OVER OAHU AND KAUAI. SHOWERS WILL BE
MOST PREVALENT OVER WINDWARD SECTIONS OF THE BIG ISLAND AND
MAUI...BUT EVEN THERE RAINFALL AMOUNTS WILL BE RELATIVELY LIGHT
DUE TO LIMITED MOISTURE. MAINLY DRY CONDITIONS WILL PREVAIL OVER
OAHU AND KAUAI...AS THIS FLOW REGIME WILL KEEP THOSE ISLANDS IN
THE RAIN SHADOW OF THE BIG ISLAND. SCATTERED SHOWERS WILL BE
POSSIBLE OVER WINDWARD OAHU AT TIMES...AS THAT AREA CAN BE FAVORED
FOR RAINFALL IN EAST-SOUTHEAST FLOW. AFTERNOON SEA BREEZES ACROSS
LEEWARD SECTIONS SHOULD PRODUCE SOME CLOUDS BUT LITTLE RAINFALL IS
EXPECTED. WINDS ARE EXPECTED TO SHIFT BACK TO A MORE TYPICAL TRADE
WIND DIRECTION BY LATE SUNDAY AS A COLD FRONT APPROACHES KAUAI.

A TRANSITION TO A BREEZY AND RATHER WET TRADE WIND PATTERN IS
FORECAST DURING THE FIRST HALF OF NEXT WEEK. STRONG HIGH PRESSURE
BUILDING FAR NORTHWEST OF THE STATE WILL PUSH A DISSIPATING
FRONTAL BOUNDARY CLOSE TO KAUAI ON MONDAY. AN INCREASE IN
RAINFALL IS LIKELY ON KAUAI BY MONDAY NIGHT AS THE FRONT DRIFTS
OVER THAT ISLAND...WITH THE BAND OF MOISTURE SPREADING OVER OAHU
AND PARTS OF MAUI COUNTY ON TUESDAY AND TUESDAY NIGHT AS THE
DISSIPATING FRONT CONTINUES DRIFTING TO THE SOUTHEAST. THE GFS AND
ECMWF CONTINUE TO DEPICT BREEZY/GUSTY TRADE WINDS SPREADING ACROSS
THE STATE MONDAY NIGHT AND TUESDAY...AND CONTINUING ON WEDNESDAY.

LONGER RANGE MODELS DEPICT THE STRONG HIGH TO OUR NORTHWEST
SINKING GRADUALLY SOUTHWARD WEDNESDAY NIGHT AND THURSDAY. THIS
PUSHES THE LINGERING MOISTURE SOUTH OF THE BIG ISLAND AND BRINGS A
MUCH DRIER AIRMASS OVER THE STATE FOR THE LATER PART OF NEXT WEEK.
BREEZY TRADES WILL CONTINUE...ALTHOUGH WINDS MAY NOT BE QUITE AS
STRONG AS THOSE OBSERVED EARLIER IN THE WEEK.

&&

.AVIATION...
VFR WILL PREVAIL OVER THE ISLANDS THROUGH SATURDAY. HOWEVER...BRIEF
MVFR CONDITIONS WITH LOWER CEILINGS AND SHOWERS ARE POSSIBLE ACROSS
E AND SE SECTIONS OF THE BIG ISLAND AND WINDWARD SECTIONS OF THE
SMALLER ISLANDS.

NO AIRMETS ARE CURRENTLY IN EFFECT.

&&

.MARINE...
NORTH-NORTHWEST SWELL CONTINUES TO RUN NEAR 8 FEET AT THE
NEARSHORE CDIP BUOYS...BUT HAS DROPPED TO BELOW 6 FEET AT BUOYS
51001 AND 51101 DURING THE PAST SEVERAL HOURS. THE EXISTING HIGH
SURF ADVISORY FOR NORTH FACING SHORES WILL REMAIN IN EFFECT FOR
THE REST OF THIS EVENING...BUT WE EXPECT THAT THIS WILL BE DROPPED
AT MIDNIGHT AS SCHEDULED. THE NEXT ROUND OF ADVISORY LEVEL SURF IS
DUE ON SUNDAY AND MONDAY...AND INCREASING NORTHEASTERLY TRADES MAY
ALSO PRODUCE HIGH SURF ALONG EAST FACING SHORES OF SOME ISLANDS ON
TUESDAY AND WEDNESDAY.

A SMALL CRAFT ADVISORY /SCA/ REMAINS IN EFFECT FOR ALL WATERS
AROUND MAUI COUNTY AND THE BIG ISLAND. THE DECLINING NORTHWEST
SWELL WILL PRODUCE SEAS UP TO 10 FT AREAS NORTH AND EAST OF THESE
ISLANDS THIS EVENING...BUT THE MAIN PURPOSE FOR THE SCA IS TO
COVER AREAS OF STRONG EASTERLY TRADE WINDS. THE SCA RUNS THROUGH
SATURDAY AFTERNOON...BUT IT MAY NEED TO BE EXTENDED IF WINDS HOLD
LONGER THAN EXPECTED. THE SCA COULD BE EXPANDED FOR SEAS ON SUNDAY
DUE TO ANOTHER NORTHWEST SWELL...AND WILL LIKELY BE POSTED AGAIN
EARLY NEXT WEEK FOR AREAS OF STRONG NORTHEAST TRADES AND HAZARDOUS
SEAS.

&&

.HFO WATCHES/WARNINGS/ADVISORIES...
SMALL CRAFT ADVISORY UNTIL 6 PM HST SATURDAY FOR MAUI COUNTY
WINDWARD WATERS-MAALAEA BAY-PAILOLO CHANNEL-ALENUIHAHA CHANNEL-
BIG ISLAND WINDWARD WATERS-BIG ISLAND LEEWARD WATERS-BIG ISLAND
SOUTHEAST WATERS.

&&

$$

UPDATE/DISCUSSION/MARINE...JACOBSON
AVIATION...KINEL



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