High Surf in Hawaii, January 28 to 29, 2012

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HONOLULU HI
830 PM HST FRI JAN 27 2012

.SYNOPSIS...
THE LAST REMNANTS OF A DISSIPATING FRONT WILL CLEAR OUT TONIGHT. AS
TRADE WINDS RETURN OVER THE WEEKEND...THEY WILL BRING A FEW SHOWERS
TO WINDWARD SLOPES...BUT CONDITIONS WILL STAY ON THE DRY SIDE OF
USUAL. TRADE WIND CONDITIONS WILL PERSIST AT LEAST THROUGH THE
MIDDLE OF NEXT WEEK.

&&

.DISCUSSION...
THE LAST VESTIGES OF A FRONT DISSIPATED ACROSS THE MIDDLE OF THE
STATE AS SURFACE RIDGING REBUILT TO THE NORTHEAST. ALTHOUGH
PRECIPITATION ASSOCIATED WITH THE FRONT HAD DIMINISHED
SUBSTANTIALLY...SHALLOW CONVECTION CONTINUED ALONG LINES OF
CONVERGENCE IN THE PREVAILING FLOW...CHIEFLY OVER THE COASTAL WATERS.

ALOFT...WHILE SOME WEAKNESS WAS PRESENT TO THE SOUTHEAST...A BROAD
RIDGE EXPANDED OVER THE MAIN HAWAIIAN ISLANDS FROM THE WEST. THE
DEEPER TROUGH FORMERLY OVER AND NORTH OF THE STATE ACCELERATED AWAY
TO THE NORTHEAST...AND ITS LOCAL INFLUENCE DIMINISHED RAPIDLY.

GUIDANCE AGREED QUITE WELL THAT DEEP RIDGING WILL PREVAIL OVER THE
ISLANDS INTO THE MIDDLE OF NEXT WEEK. AT THE SURFACE...THE FULLY
REINSTATED SUBTROPICAL RIDGE TO THE NORTH WILL REBUILD THE TRADE
WINDS. ALTHOUGH SOME OROGRAPHIC RAINFALL IS LIKELY ALONG WINDWARD
SLOPES...BOTH SATELLITE ESTIMATES AND MODEL PREDICTIONS OF
PRECIPITABLE WATER UPWIND WERE SUBSTANTIALLY BELOW CLIMATOLOGY...SO
ACCUMULATION SHOULD REMAIN ON THE LIGHT SIDE THROUGH MOST OF THE
FORECAST PERIOD.

AROUND NEXT WEDNESDAY...GUIDANCE SUGGESTS THAT THE SHALLOW TROUGHING
ALOFT TO THE SOUTHEAST WILL MERGE WITH A DIGGING TROUGH TO THE
NORTHEAST...WHILE A WEAK FRONT APPROACHES FROM THE NORTHEAST AT THE
SURFACE. HOWEVER...DESPITE THE DEVELOPING TROUGH TO THE EAST...AN
EXTENSION OF THE MID-LEVEL RIDGE WILL PERSIST OVER THE ISLANDS
THEMSELVES...AND MODELS PREDICT THE FRONT TO LOSE MOST OF ITS
STRENGTH BEFORE EVEN APPROACHING THE STATE. THUS...THE MAIN
PRACTICAL EFFECT MAY BE LIMITED TO A SLIGHT WEAKENING OF THE TRADES
FROM WEDNESDAY NIGHT INTO THURSDAY...AND THEN A SMALL INCREASE IN
WINDWARD SHOWERS UNTIL NEXT FRIDAY.

&&

.MARINE...
SURF WILL BUILD ABOVE THE ADVISORY LEVEL BY EARLY SATURDAY MORNING
ON KAUAI...AND COULD APPROACH 20 FEET BY SATURDAY AFTERNOON. A HIGH
SURF ADVISORY IS IN EFFECT FOR THIS EVENT. A LARGER NORTHWEST SWELL
MAY PRODUCE WARNING-LEVEL SURF ON MONDAY FOR NORTH AND WEST SHORES.

A SMALL CRAFT ADVISORY LIKELY WILL EXPAND TO COVER MOST OF THE
COASTAL WATERS FOR WIND AND COMBINED SEAS BY SATURDAY.

&&

.AVIATION...
EXPECT VFR CONDITIONS TO PREVAIL AT THE TERMINALS TONIGHT. BRIEF
PERIODS OF MVFR CONDITIONS ARE POSSIBLE DUE TO SOME LOW CEILINGS AND
BRIEF SHOWERS ALONG WINDWARD FACING SLOPES OF A FEW ISLANDS. THE
STRENGTHENING LOW-LEVEL TRADE WIND FLOW WILL LIKELY REQUIRE AN
AIRMET FOR TEMPO MODERATE LOW LEVEL TURBULENCE IN THE LEE OF THE
MOUNTAINS ON MOST ISLANDS BY SATURDAY NIGHT. NO OTHER AIRMETS ARE
EXPECTED.

&&

.HFO WATCHES/WARNINGS/ADVISORIES...
HIGH SURF ADVISORY FOR NORTH- AND WEST-FACING SHORES OF NIIHAU...
KAUAI...AND OAHU FROM MIDNIGHT TONIGHT THROUGH SUNDAY AFTERNOON.

SMALL CRAFT ADVISORY FROM MIDNIGHT TONIGHT TO 6 PM 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-PAILOLO CHANNEL-
ALENUIHAHA CHANNEL-BIG ISLAND WINDWARD WATERS.

&&

DISCUSSION AND MARINE...RYSHKO
AVIATION...HOUSTON