851 
FXHW60 PHFO 071330
AFDHFO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HONOLULU HI
400 AM HST FRI NOV 7 2014

.SYNOPSIS...
SEA BREEZES MAY PRODUCE A FEW SHOWERS THIS AFTERNOON. MORE 
WIDESPREAD RAIN WILL SPREAD OVER THE STATE AHEAD OF A COLD FRONT 
APPROACHING FROM THE NORTH FROM THIS EVENING INTO SUNDAY. GUSTY 
NORTHERLY WINDS WILL FOLLOW THE FRONT...BUT THEN BECOME LIGHTER AND 
MORE EASTERLY INTO NEXT WEEK AS THE SHOWERS DIMINISH.

&&

.DISCUSSION...
SURFACE OBSERVATIONS AROUND THE MAIN HAWAIIAN ISLANDS REPORTED 
GENERALLY LIGHT WINDS. MORE SIGNIFICANTLY FOR THE FIRST HALF OF THE 
FORECAST PERIOD...TWO FRONTS LURKED TO THE NORTH OF THE STATE. THE 
FIRST...AND CLOSEST...HAD MOVED LITTLE DURING THE PAST 48 HOURS... 
AND NOW SHOWED DEFINITE SIGNS OF WEAKENING. A SECOND...MORE VIGOROUS 
FRONT ARRIVING FROM FURTHER NORTH THREATENED TO OVERTAKE THE 
FIRST...AND THEN TO PROCEED SOUTH ACROSS THE STATE AFTER MERGING. 
THE CURRENT FORECAST PREDICTED THIS PROCESS TO CONTINUE THROUGH THE 
WEEKEND...ENDING WITH THE MERGED FRONTS STALLING NEAR THE BIG ISLAND 
BY AROUND SUNDAY.

RECENT SOLUTIONS SUGGESTED THAT UPPER-LEVEL SUPPORT...IN THE FORM OF 
A SHARPLY DIGGING LONG-WAVE TROUGH TO THE NORTH NORTHEAST OF THE 
STATE...MAY BEGIN TO FADE SIGNIFICANTLY BY EARLY ON SATURDAY...AND 
BE EFFECTIVELY GONE BY SUNDAY AS THE TROUGH RECEDES TO THE 
NORTHEAST. RESIDUAL MOMENTUM IN THE LOW-LEVEL AIR MASS BEHIND 
THE COMPOSITE FRONT SHOULD PROVE SUFFICIENT TO PUSH THE BOUNDARY ALL 
THE WAY TO THE BIG ISLAND...THOUGH IT MAY NOT BE ESPECIALLY SOLID 
WHEN IT ARRIVES.

INDIVIDUAL MODELS DISAGREED...BUT CONSENSUS SUGGESTED THAT RAINFALL 
SHOULD INCREASE IN CONVERGING SOUTHEASTERLY FLOW AHEAD OF THE 
FRONT. STRATUS RAIN WILL BE WIDESPREAD...BUT ALSO SHOULD REMAIN ON 
THE LIGHT SIDE IN THE ABSENCE OF STRONG DYNAMICS OR UNUSUALLY LARGE 
SUPPLIES OF MOISTURE. AS NORTHERLY WINDS FOLLOWING THE FRONT TURN 
NORTHEASTERLY...REMAINING MOISTURE WILL BE SQUEEZED OUT ALONG 
WINDWARD SLOPES...FOLLOWED BY GRADUAL DRYING IN THE COOLER AND DRIER 
POST-FRONTAL AIR MASS.

BY EARLY NEXT WEEK...GUIDANCE PREDICTED THE SURFACE RIDGE TO START 
SHIFTING SOUTH TOWARD THE STATE AHEAD OF ANOTHER APPROACHING FRONT. 
THUS...TRADE WINDS WILL RETURN...AND THEN DIMINISH GRADUALLY INTO 
MID-WEEK. SOME SHOWERS WILL BE POSSIBLE WINDWARD...AND WHERE 
SUPPORTED BY AFTERNOON SEA BREEZES...BUT ON THE WHOLE CONDITIONS 
SHOULD TREND TOWARD THE DRY SIDE OF AVERAGE.

MODEL CONSENSUS SUGGESTED THAT THE NEW FRONT WILL APPROACH KAUAI 
AROUND WEDNESDAY...BUT MAY DELAY MOVING FURTHER SOUTH UNTIL AROUND 
THURSDAY. THUS...MORE PRECISE TIMING WAS DIFFICULT TO PIN DOWN AT 
THIS TIME. A NUMBER OF SOLUTIONS HINTED THAT THIS NEW FRONT MAY NOT 
BE AS STRONG...OR REACH AS FAR SOUTH...AS THE ONE DUE THIS WEEKEND. 
HOWEVER...SHOWERS FORMING IN THE CONVERGENCE AHEAD OF THE FRONT 
STILL SHOULD AFFECT MOST OF THE STATE.

&&

.MARINE...
THE SHRINKING NORTH-NORTHWEST SWELL SHOULD CONTINUE TO SUBSIDE 
TODAY. A LARGER NORTH-NORTHWEST SWELL IS EXPECTED TO REACH THE 
ISLANDS EARLY SATURDAY...AND THEN TO PEAK ON SATURDAY NIGHT. THIS 
SWELL LIKELY WILL REQUIRE A HIGH SURF ADVISORY FOR NORTH- AND 
WEST-FACING SHORES TONIGHT AND SATURDAY. AS THIS NORTH-NORTHWEST 
SWELL ARRIVES...A COLD FRONT MOVING ALONG THE ISLAND CHAIN WILL 
BRING GUSTY NORTHERLY WINDS...THUS CREATING HAZARDOUS SEAS OVER 10 
FEET IN HEIGHT ALONG AND NORTH OF THE FRONT TONIGHT AND SATURDAY.

&&

.HFO WATCHES/WARNINGS/ADVISORIES...
SMALL CRAFT ADVISORY FROM 6 PM SATURDAY TO 6 AM HST SUNDAY FOR 
ALENUIHAHA CHANNEL-BIG ISLAND WINDWARD WATERS-BIG ISLAND LEEWARD 
WATERS.

SMALL CRAFT ADVISORY FROM 6 PM THIS EVENING TO 6 AM HST SUNDAY 
FOR KAUAI NORTHWEST WATERS-KAUAI WINDWARD WATERS-KAUAI LEEWARD 
WATERS-KAUAI CHANNEL-OAHU WINDWARD WATERS-OAHU LEEWARD WATERS-
KAIWI CHANNEL-MAUI COUNTY WINDWARD WATERS-MAUI COUNTY LEEWARD 
WATERS-MAALAEA BAY-PAILOLO CHANNEL.

&&

$$

RYSHKO