Area Forecast Discussion
Issued by NWS Honolulu, HI

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
000
FXHW60 PHFO 200643
AFDHFO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HONOLULU HI
843 PM HST TUE AUG 19 2014

.SYNOPSIS...
TRADE WIND WEATHER WILL CONTINUE THROUGH THE WEEK WITH SHOWERS
FAVORING WINDWARD AND MOUNTAIN LOCATIONS. EXPECT A FEW SHOWERS
TO REACH LEEWARD LOCATIONS AS WELL.

&&

.DISCUSSION...
TRADE SHOWERS HAVE BEEN FAIRLY ACTIVE ACROSS WINDWARD AREAS
DURING THE PAST SEVERAL HOURS...WITH A FEW RAIN GAUGES RECORDING
SIX HOUR TOTALS OVER A HALF INCH. PERSISTENT SHOWERS ALSO
DEVELOPED ONCE AGAIN ON THE KONA COAST EARLY THIS EVENING...BUT
HAVE NOT PRODUCED THE LOCALLY HEAVY RAINFALL RATES THAT THEY DID
ON MONDAY EVENING. SURFACE ANALYSIS DEPICTS THE NORTHEAST PACIFIC
HIGH IN ITS TYPICAL SUMMERTIME POSITION ABOUT 1500 MILES NORTHEAST
OF HONOLULU...WITH MODERATE TRADES PREVAILING OVER HAWAII.
ALOFT...A WEAK UPPER LOW IS LIFTING NORTH OF THE STATE...WITH A
RIDGE AXIS EXTENDING WESTWARD ACROSS THE BIG ISLAND. THE 00Z
SOUNDINGS IMPLY THAT A DRIER AND MORE STABLE AIRMASS IS SPREADING
IN FROM THE EAST...WITH HILO REPORTING A WELL DEFINED INVERSION
BASED NEAR 6000 FEET AND WELL BELOW NORMAL PWAT OF BARELY OVER
ONE INCH...WHILE LIHUE REPORTED A WEAKER/HIGHER INVERSION WITH
PWAT OF 1.35 INCHES. MIMIC-TPW SATELLITE IMAGERY DEPICTS A RATHER
DRY AIRMASS IMMEDIATELY TO OUR EAST...WITH THE LEADING EDGE OF AN
AREA OF CONSIDERABLY HIGHER TROPICAL MOISTURE ABOUT 300 MILES
EAST OF THE BIG ISLAND.

OVERNIGHT...EXPECT TYPICAL PASSING SHOWERS ACROSS WINDWARD
SECTIONS...WITH RAINFALL AMOUNTS MOSTLY REMAINING LIGHT. A FEW
SHOWERS MAY REACH SOME LEEWARD LOCATIONS...BUT MOST LEE AREAS
WILL REMAIN DRY. THE EXISTING FORECAST APPEARS TO BE ON TRACK...
AND NO UPDATES ARE PLANNED FOR THIS EVENING.

LITTLE CHANGE IS EXPECTED THROUGH THE NEXT SEVERAL DAYS...
WITH TRADE WIND WEATHER CONTINUING. MODEL CONSENSUS FORECASTS
THE NORTHEAST PACIFIC HIGH TO REMAIN STATIC THROUGH THE
WEEKEND...THEN POSSIBLE WEAKEN SOMEWHAT EARLY NEXT WEEK AS A COLD
FRONT MOVES THROUGH THAT REGION. ONCE THE UPPER LOW INITIALLY NORTH
OF THE STATE LIFTS AWAY...RIDGING ALOFT SHOULD PREVAIL OVER THE
STATE THROUGH THE END OF THIS WEEK AND INTO THE WEEKEND...WITH
ANOTHER VERY WEAK MID/UPPER LEVEL TROUGH POSSIBLY DEVELOPING
NEARBY EARLY NEXT WEEK. DAY TO DAY WEATHER VARIATIONS ACROSS
HAWAII WILL BE LARGELY DRIVEN BY CHANGES IN AVAILABLE MOISTURE.
ONE AREA OF ENHANCED TROPICAL MOISTURE WILL CROSS THE STATE
WEDNESDAY NIGHT INTO THURSDAY...WITH THE DEEPEST MOISTURE
APPEARING LIKELY TO AFFECT THE BIG ISLAND AND MAUI COUNTY. WOULD
EXPECT ENHANCED TRADE SHOWERS DURING THIS TIME...WITH SOME SHOWERS
SPILLING OVER INTO LEEWARD AREAS. NEAR AVERAGE MOISTURE LEVELS
WILL THEN PREVAIL FROM FRIDAY INTO THE WEEKEND...WITH ANOTHER BAND
OF SLIGHTLY HIGHER MOISTURE POSSIBLY MOVING ACROSS THE AREA SUNDAY
AND SUNDAY NIGHT.

THE TROPICS REMAIN ACTIVE IN THE EAST PACIFIC...BUT LATEST
FORECASTS FROM THE NATIONAL HURRICANE CENTER AND GLOBAL MODELS
KEEP ANY TROPICAL SYSTEMS FAR AWAY FROM HAWAII THROUGH THE
FORESEEABLE FUTURE.

&&

.AVIATION...
VFR WILL PREVAIL OVER MOST AREAS THROUGH THE EVENING HOURS AND
OVERNIGHT.  HOWEVER...BRIEF PERIODS OF MVFR IN LOWER CLOUDS AND
SHOWERS ARE LIKELY TO AFFECT WINDWARD COASTAL AND MAUKA SECTIONS
ACROSS THE STATE...AND POSSIBLY COASTAL AND LOWER UPSLOPE PORTIONS
OF KONA ON THE LEE SIDE OF THE BIG ISLAND.

&&

.MARINE...
A LATE TUESDAY MORNING ASCAT PASS FOUND AREAS OF WINDS JUST BELOW
SMALL CRAFT ADVISORY /SCA/ LEVELS IN THE ALENUIHAHA CHANNEL AND
SOUTH OF THE BIG ISLAND. MAY NEED TO POST A SCA FOR THOSE
TYPICALLY WINDIER WATERS AROUND MAUI COUNTY AND THE BIG ISLAND
LATE TONIGHT...PENDING POSSIBLE ADDITIONAL DATA FROM THE
OVERNIGHT ASCAT PASS. EXPECT TRADE WINDS TO REMAIN CLOSE TO
ADVISORY LEVELS IN THOSE WATERS THROUGH THE REST OF THIS WEEK.

SOUTH SWELL WILL MAINTAIN ABOVE AVERAGE SURF ALONG SOUTH FACING
SHORES THROUGH THE REST OF THIS WEEK. A DIMINISHING SSW SWELL
TONIGHT WILL BE REPLACED BY ANOTHER PULSE FROM THE SSW WEDNESDAY
THROUGH FRIDAY. SURF MAY APPROACH ADVISORY LEVELS ACROSS SOUTH
FACING SHORES ON THURSDAY. SEE THE COLLABORATIVE NEARSHORE SWELL
AND WIND FORECAST FOR OAHU /SRDHFO/ FOR MORE DETAILS.

&&

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

&&

$$

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






USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.