Weather Service Report


761 
FXHW60 PHFO 021950
AFDHFO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HONOLULU HI
1000 AM HST THU JUL 2 2015

.SYNOPSIS...
LIGHT WINDS WILL CONTINUE ACROSS THE SMALLER ISLANDS THROUGH MUCH OF 
FRIDAY...WITH SOME HINTS OF LIGHT TRADE WINDS RETURNING SATURDAY. 
WIDESPREAD MODERATE TRADES SHOULD RETURN STATE WIDE DURING THE 
MIDDLE OF NEXT WEEK. LIGHT WINDS TODAY AND TOMORROW WILL CONTINUE TO 
BRING LAND AND SEA BREEZES...ALONG WITH AFTERNOON CLOUDS AND 
SHOWERS. THE LIGHT TRADE WINDS SATURDAY AND SUNDAY WILL ALLOW FOR 
LOCALIZED LAND AND SEA BREEZES. EXPECT MORE TYPICAL TRADE WINDS AS 
THE MIDDLE OF NEXT WEEK APPROACHES. 

&&

.DISCUSSION...
SATELLITE AND RADAR DATA BOTH SHOW MORE CLOUDS AND SHOWERS OVER THE 
BIG ISLAND AND THE PORTIONS OF MAUI THIS MORNING THAN OVER THE 
REMAINING ISLANDS. PRECIPITABLE WATER SHOWS A SLIGHTLY DRIER AIRMASS 
OVER THE WESTERN ISLANDS THIS MORNING...BUT VALUES REMAIN AROUND 
NORMAL FOR THIS TIME OF YEAR. CLOUDS ARE BEGINNING TO FORM OVER THE 
KOOLAU RANGE ON OAHU...AND OVER THE INTERIOR OF KAUAI AT 9 AM. WITH 
THIS COMBINATION...DO FEEL THAT AFTERNOON CLOUDS AND SHOWERS REMAIN 
A POSSIBILITY...PARTICULARLY OVER LEEWARD AND INTERIOR SECTIONS OF 
THE SMALLER ISLANDS. HAVE UPDATED THE FORECAST TO TREND THE POPS 
HIGHER...FOLLOWING GUIDANCE FROM ALL THE MODELS...GLOBAL AND HIGH 
RES. 

ALTHOUGH WE DO EXPECT TRADES TO RETURN...IT WILL BE A VERY SLOW 
RETURN. LIGHT WINDS TODAY AND TOMORROW WILL CONTINUE TO BRING 
WIDESPREAD LAND AND SEA BREEZES TO THE ISLANDS. THIS COMBINATION 
WILL CONTINUE TO BRING WARM AND HUMID CONDITIONS TO THE ISLANDS. AS 
THE WINDS START TO PICK UP THIS WEEKEND...EVEN THOUGH THEY WILL 
START TO BE FROM A MORE TRADE WIND DIRECTION...WIND SPEEDS WILL 
REMAIN LIGHT...PARTICULARLY OVER THE SMALLER ISLANDS. AS 
SUCH...LOCALIZED LAND AND SEA BREEZES WILL PERSIST. HOWEVER THE 
BACKGROUND FLOW WILL BE FROM THE NORTHEAST...WHICH SHOULD FOCUS 
LIMITED SHOWER ACTIVITY TO THE EASTERN SIDES OF THE ISLANDS. 

THE LIGHT WINDS ARE DUE TO A FRONT TO THE NORTHWEST OF THE ISLANDS 
PUSHING THE SURFACE RIDGE OVER THE ISLANDS. THE LOW ASSOCIATED WITH 
THE FRONT...FAR NORTH OF THE ISLANDS...IS EXPECTED TO LIFT NORTH 
THROUGH THE WEEKEND. AS IT LIFTS NORTH...THE FRONT WILL LIFT TO THE 
NORTH...ALLOWING THE RIDGE TO RETREAT TO THE NORTH. THE HIGH 
PRESSURE SYSTEM WILL REMAIN FAR NORTHEAST OF THE ISLANDS. THE 
RESULTANT PRESSURE GRADIENT OVER THE ISLANDS WILL PREVENT TRADES 
FROM EXCEEDING MODERATE LEVELS IN MOST AREAS DURING THE SECOND HALF 
OF NEXT WEEK.

&&

.AVIATION...
A COLD FRONT APPROX 100NM NW OF KAUAI HAS PUSHED THE RIDGE OVER THE 
ISLANDS. LIGHT AND VARIABLE WINDS WILL PREVAIL OVER THE SMALLER 
ISLANDS AND LEEWARD BIG ISLAND AND ALLOW FOR A SEA/LAND BREEZE 
REGIME TO REMAIN INTO FRIDAY. A LIGHT E-SE FLOW WILL REMAIN AROUND 
WINDWARD BIG ISLAND.

MIMIC TOTAL PRECIPITABLE WATER IMAGERY SHOWS A SWATH OF ENHANCE 
MOISTURE OVER MAUI COUNTY AND THE THE BIG ISLAND. MORNING SOUNDINGS 
ESTIMATE 1.58 AND 1.17 INCHES OF PRECIPITABLE WATER OVER PHTO AND 
PHLI RESPECTIVELY. WHILE OAHU AND KAUAI ARE IN A DRY SLOT THIS 
MORNING...FORECAST MODELS SHOWS THE AREA OF ENHANCED MOISTURE 
SPREADING WEST INTO FRIDAY. EXPECT SEA BREEZES TO ALLOW FOR 
INTERIOR CLOUDS AND SHOWERS TO FORM OVER INTERIOR AREAS ON ALL 
ISLANDS THIS AFTERNOON. SOME SHOWERS MAY BRING MVFR CONDITIONS AND 
TOPS UP TO 150...ESPECIALLY OVER MAUI AND THE BIG ISLAND.  
&&

.MARINE...
SMALL CRAFT ADVISORY /SCA/ CONDITIONS ARE NOT ANTICIPATED THROUGH 
THE HOLIDAY WEEKEND. THERE IS THE POTENTIAL FOR SCA IN THE WINDIER 
MARINE ZONES AROUND MAUI AND THE BIG ISLAND EARLY NEXT WEEK DUE TO 
THE STRENGTHENING TRADES. 

THE SOUTH SHORES WILL SEE QUITE A BIT OF SWELL ACTION OVER THE 
WEEKEND DUE TO A FAIRLY ACTIVE WEATHER PATTERN IN THE SOUTHERN
HEMISPHERE THE PAST SEVERAL DAYS. SWELLS GENERATED BY SEVERAL 
FAST-MOVING LOWS ARE ON THEIR WAY HERE THAT WILL RESULT IN A SMALL 
TO MODERATE SIZE SURF OVER THE HOLIDAY WEEKEND. PEAKS IN SURF 
HEIGHTS ARE EXPECTED TONIGHT AND ON SUNDAY...APPROACHING BUT STAYING 
BELOW ADVISORY LEVELS. 

A NORTHWEST SWELL HAS REACHED THE ISLANDS AND AS EXPECTED. THIS 
SWELL IS EXPECTED TO PEAK BELOW ADVISORY LEVELS LATER TODAY...AND 
THEN SLOWLY SUBSIDE THROUGH FRIDAY. 

&&

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

&&

$$

DISCUSSION/MARINE...M BALLARD
AVIATION...EATON







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