902
FXHW60 PHFO 041531 AAA
AFDHFO
AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE HONOLULU HI
532 AM HST WED NOV 4 2009
SYNOPSIS
THE DEVELOPING UPPER LEVEL LOW WEST OF KAUAI WILL CONTINUE TO MOVE
WESTWARD ALLOWING FOR MORE SUN TO BREAK THROUGH TODAY. TRADE WINDS
WILL CONTINUE TO FOCUS SHOWERS OVER WINDWARD AND MOUNTAIN AREAS OVER
THE NEXT SEVERAL DAYS. WINDS WILL BECOME MORE SOUTHEASTERLY OVER THE
WEEKEND.
DISCUSSION
THE FORECAST LOOKS IN PRETTY GOOD SHAPE TO START WEDNESDAY. SHOWERS
ARE STARTING TO EASE UP AS SOME SLIGHTLY DRIER AREA BEGINS TO NOSE
INTO THE AREA AS INDICATED IN THE PRECIPITABLE WATER IMAGERY. THE
UPPER LOW TO OUR WEST CONTINUES TO WRAP UP AS IT SLIDES WESTWARD. IT
IS CARRYING THE HIGHER LEVEL CIRRUS AWAY FROM THE STATE AS WELL.
THIS SHOULD LEAVE SKIES GENERALLY ON THE SUNNIER SIDE AROUND
DAYBREAK WHILE WINDWARD AND MOUNTAIN AREAS STILL HAVE MOSTLY CLOUDY
SKIES.
ANOTHER SLOWLY DISSIPATING FRONTAL BAND CAN BE SEEN JUST NORTH OF
THE STATE IN MOST SATELLITE PRODUCTS. THIS SHOULD BEGIN TO IMPACT
THE AREA LATER THIS AFTERNOON. DID ADJUST POPS ACCORDINGLY FOR THE
SMALLER ISLANDS. THE BIG ISLAND MAY SEE INCREASED WINDWARD SHOWERS
TONIGHT WITH A SLIGHT CHANCE OF A FEW SHOWERS REACHING
INTERIOR/SUMMITS WITH THE WEAKLY CAPPED ATMOSPHERE AND ELEVATED
INVERSION.
WITH HIGH PRESSURE NORTH OF THE STATE...SLOWLY MIGRATING
EAST...STILL CALLING FOR TRADES AND A WINDWARD FOCUSED POP REGIME
THROUGH THE REMAINDER OF THE WORK WEEK. PRESSURE/HEIGHT RISES
NORTHEAST OF THE STATE COMBINED WITH THE INVERTED SURFACE TROUGH
ASSOCIATED WITH UPPER LOW JUST TO OUR WEST WILL LEAD TO VEERED
EAST/EAST-SOUTHEAST TRADES THIS WEEKEND.
THE LONGER TERM FORECAST TO FINISH OUT THE WEEKEND INTO NEXT WEEK
WAS AND REMAINS A CHALLENGE. GLOBAL MODELS ARE ALMOST COMPLETELY OUT
OF PHASE IN THE VICINITY OF HAWAII COME EARLY NEXT WEEK WITH
SOMEWHAT SPLIT ENSEMBLE SUPPORT. DID HAVE TO SHIFT THE FORECAST
TOWARD SOME DEGREE OF CLIMO AS MODEL VARIABILITY WAS TOO HIGH TO
MAKE ANY CERTAIN CHANGES OR EVEN MAINTAIN CONTINUITY FOR DAYS 6 AND
7. THE LONG RANGE FORECAST IS OF LOW CONFIDENCE RIGHT NOW AND WILL
NEED TO BE FINE TUNED AS GUIDANCE RESOLVES SOME DIFFERENCES THROUGH
THE PERIOD.
PREVIOUS DISCUSSION
/ISSUED 800 PM HST TUESDAY NOV 3/
THE FORECAST IS LOOKING OK TO START THE MID SHIFT. REGARDLESS OF
ANY MINOR TWEAKS...IT LOOKS LIKE A PRETTY SHOWERY NIGHT IS IN STORE
FOR MOST OF THE STATE...WITH THE BIG ISLAND STAYING THE DRIEST OF
THE ISLANDS.
NOT ANTICIPATING ANY BIG CHANGES TO THE FORECAST TONIGHT. DEEP
LAYERED TROUGHING OVER THE EASTERN NORTH PACIFIC WILL KEEP HIGH
PRESSURE NEARLY STATIONARY TO OUR NORTHWEST WITH ITS ATTENDANT RIDGE
NORTHEAST OF HAWAII. THE INFRARED SATELLITE IMAGERY CLEARLY DEPICTS
MID LEVEL CYCLOGENESIS JUST WEST OF THE STATE AT THIS TIME. AS OF
NOW...GLOBAL SOLUTIONS ONLY DEVELOP A WEAK SURFACE REFLECTION AS THE
UPPER LOW DRIFTS SLOWLY WESTWARD WHILE UNDERCUTTING THE DEEP LAYERED
HIGH TO THE NORTH. AS THE LOW CONTINUES TO TRACK WEST...EXPECT
RISING 500 MB HEIGHTS LOCALLY WHICH WILL STRENGTHEN THE LOW LEVEL
SUBSIDENCE INVERSION AGAIN LIMITING THE VERTICAL DEVELOPMENT OF ANY
SHOWERS. SHOWER ACTIVITY WILL BECOME EVEN MORE FOCUSED ON WINDWARD
ZONES ALLOWING LEEWARD SECTIONS TO DRY OUT SOME COMPARED TO TODAY
AND MONDAY.
EXPECT TRADES FOR THE REMAINDER OF THE WORK WEEK WITH INTERMITTENT
PERIODS OF MORE PERSISTENT RAINFALL AS BANDS OF REMNANT FRONTAL
MOISTURE PASS OVER THE AREA. DURING THE REMAINDER WEEK...
PRESSURES/HEIGHTS WILL RISE OVER THE FAR EASTERN NORTH PACIFIC AS
THE POLAR JET FLATTENS. THIS WILL ALLOW HIGH PRESSURE TO OUR
NORTH TO SLIDE EASTWARD. ALONG WITH THE AFOREMENTIONED UPPER LOW AND
ITS ASSOCIATED INVERTED SURFACE TROUGH...THIS WILL CAUSE TRADE WINDS
TO BEGIN VEERING TO THE SOUTHEAST OVER THE WEEKEND. THE GFS AND
ECMWF...ALONG WITH GFS ENSEMBLES SUGGEST HEIGHT FALLS OVER THE
CENTRAL NORTH PACIFIC DUE TO A DEVELOPING SOUTHERN STREAM
SHORTWAVE...ALTHOUGH GUIDANCE STILL HAS TO RESOLVE MODERATE
DIFFERENCES REGARDING INTENSITY AND SURFACE FEATURES. CONFIDENCE IN
SOUTHEASTERLY FLOW ACROSS THE STATE OVER THE WEEKEND INTO EARLY NEXT
WEEK IS FAIR. IT IS FAR TOO EARLY TO DETERMINE ANY FRONTAL IMPACTS
DURING THE FIRST HALF OF NEXT WEEK THOUGH. WILL REVISIT THIS TONIGHT
FOR THE ADDITION OF DAY 7 TO THE GRIDS.
MARINE
/UPDATED 900 PM HST TUESDAY NIGHT/
THE SMALL CRAFT ADVISORY/SCA HAS BEEN ADJUSTED DUE TO IMPROVING
CONDITIONS AROUND KAUAI. THE SCA IS NOW FOR THE TYPICALLY WINDIER
LOCATIONS IN THE VICINITY OF THE BIG ISLAND.
SURF ALONG AROUND THE ISLAND SHOULD BE MORE TAME OVER THE NEXT
SEVERAL DAYS. NORTH FACING EXPOSURES WILL SEE BUILDING SURF
WEDNESDAY...REACHING UP TO DOUBLE OVERHEAD FOR STANDOUT
REEFS/BEACHES THURSDAY. SHORTER PERIOD NORTH TO NORTHEAST SWELL WILL
POTENTIALLY LEAD TO LUMPY MIXED UP CONDITIONS...WHICH SHOULD IMPROVE
TO FINISH OUT THE REMAINDER OF THE WEEK. SOUTH FACING SHORES WILL
BEGIN AN INCREASING TREND THURSDAY WITH MOST AREAS EXPECTED TO CLIP
THE WAIST TO CHEST HIGH RANGE BY FRIDAY. TOP SOUTH FACING BREAKS
WILL BE UP TO HEAD HIGH PLUS ON THE BETTER SET WAVES. GUIDANCE AND
BUOYS INDICATE THAT THE SURF ON KAUAI HAS DROPPED BELOW ADVISORY
LEVELS...BUT WILL STILL REMAIN ELEVATED TODAY POSSIBLY REACHING UP
TO 12 FEET AT TIMES. THE ADVISORY WILL BE CANCELLED WITH THE MORNING
FORECAST PACKAGE.
AVIATION
THE TERMINALS ARE LOOKING AT MAINLY VFR CONDITIONS TODAY. PHNY MAY
SEE SOME OF THE TYPICAL LOWER AFTERNOON CIGS DUE TO THE FIELD
ELEVATION. MOST MVFR CONDITIONS WILL REMAIN MOSTLY CONTAINED
ALONG/OVER WINDWARD AND MOUNTAIN TERRAIN. HIGHER BKN/OVC CIRRUS WILL
THIN THROUGH THE FIRST HALF OF THE DAY.
THE DEVELOPING UPPER LOW WEST OF KAUAI CONTINUES TO MOVE WESTWARD.
THE DIFFLUENT EXIT REGION OF THE 80-90KT IS SHIFTING TO THE WEST
WITH IT. THE HIGH LEVEL TURBULENCE NOW BETWEEN FL190/FL250 SHOULD
END OVER THE IMMEDIATE AREA AROUND SUNRISE AFT 04/15Z. TRADE WINDS
NEAR THE SURFACE WILL CONTINUE TO PRODUCE LOW LEVEL TURBULENCE LEE
OF THE KAUAI MOUNTAINS AOB 060 TODAY.
HFO WATCHES/WARNINGS/ADVISORIES
HIGH SURF ADVISORY CANCELLED.
SMALL CRAFT ADVISORY UNTIL 6 PM HST THIS EVENING FOR ALENUIHAHA
CHANNEL-BIG ISLAND SOUTHEAST WATERS.
DEJESUS
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