Area Forecast Discussion
Issued by NWS Honolulu, HI

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000
FXHW60 PHFO 261929
AFDHFO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HONOLULU HI
1000 AM HST SAT JUL 26 2014

.SYNOPSIS...
MODERATE TRADE WINDS WILL FOCUS SHOWERS MAINLY ACROSS WINDWARD
AND MAUKA AREAS. TRADE SHOWERS MAY BR HEAVIER TODAY THROUGH SUNDAY
AS AN UPPER TROUGH ACTS ON A PASSING AREA OF INCREASED MOISTURE
EMBEDDED WITHIN THE TRADES. TRADES MAY STRENGTHEN SOMEWHAT BY EARLY
NEXT WEEK.

&&

.DISCUSSION...
A 1024 MB HIGH NEAR 38N142W...FAR NORTHEAST OF THE MAIN HAWAIIAN
ISLANDS...HAS AN ASSOCIATED RIDGE EXTENDING EAST TO WEST ALONG 38N.
THE PRESSURE GRADIENT BETWEEN THIS HIGH AND EQUATORIAL LOW PRESSURE
IS SUFFICIENTLY STEEP TO SUPPORT MODERATE TRADE WINDS ACROSS LOCAL
WATERS THIS MORNING. RADAR AND SATELLITE LOOPS SHOW A RATHER TYPICAL
TRADE WIND WEATHER DISTRIBUTION OF CLOUDS AND SHOWERS FAVORING
WINDWARD AND MAUKA AREAS. ONLY A FEW WINDWARD RAIN GAUGES REPORTED
NOTICEABLE RAINFALL OVERNIGHT...WITH ONE OR TWO WINDWARD OAHU
LOCATIONS REPORTING 1/4 TO 1/2 INCH OF RAINFALL OVER THE 12 HOUR
PERIOD ENDING AT 8 AM. BROKEN LOW CLOUDS ARE NOTED FROM JUST EAST OF
THE ISLANDS ALL THE WAY TO 140W AND BEYOND...AND WE EXPECT A
CONTINUED FOCUS FOR CLOUDS AND SHOWERS ACROSS WINDWARD AND MAUKA
AREAS THROUGH THE FORECAST PERIOD AS THIS MOISTURE STREAMS IN. TRADE
SHOWERS MAY BE HEAVIER AT TIMES THROUGH SUNDAY AS UPPER TROUGHING
ACTS ON A PASSING AREA OF ENHANCED MOISTURE EMBEDDED IN THE TRADES.

THE HIGH FAR TO OUR NORTHEAST IS FORECAST TO WEAKEN SOMEWHAT AS A
COLD FRONT MOVES EASTWARD NORTH OF 30N...BUT AT THE SAME TIME A
TROPICAL LOW PASSING WELL SOUTH OF THE STATE MAY BE ABLE TO MAINTAIN
OR EVEN TIGHTEN THE PRESSURE GRADIENT LOCALLY. OVERALL...WE EXPECT A
TYPICAL TRADE WIND PATTERN TO PREVAIL THROUGH AT LEAST TUESDAY
NIGHT...WITH PASSING SHOWERS MAINLY AFFECTING WINDWARD AND MAUKA
AREAS.

EARLIER MODEL GUIDANCE BROUGHT A SURGE OF DEEP TROPICAL MOISTURE UP
TOWARD THE STATE FROM THE SOUTHEAST TOWARD THE LATER PART OF NEXT
WEEK AND INTO NEXT WEEKEND. LATER GUIDANCE...LIKE THE 12Z GFS
RUN...BACKS OFF ON THIS. IF IT ARRIVES...THIS MOISTURE WOULD BE
ASSOCIATED WITH THE REMNANTS OF CURRENT EAST PACIFIC TROPICAL
DEPRESSION GENEVIEVE. HOWEVER...MODELS REMAIN INCONSISTENT WITH BOTH
THE TIMING AND EXTENT OF ANY POSSIBLE MOISTURE SURGE AND CONFIDENCE
IS TOO LOW TO INCLUDE IT IN THE FORECAST AT THIS TIME.

&&

.AVIATION...
THIS MORNING LEEWARD TERMINALS ARE CLEAR...AND WINDWARD TERMINALS
ARE EXPERIENCING ISOL MVFR CONDITIONS EMBEDDED WITHIN FEW PASSING
LOWER CLOUDS AND SHOWERS. WINDWARD SHOWERS ARE EXPECTED TO INCREASE
FROM EAST TO WEST LATER TODAY...AS A POCKET OF MOISTURE JUST N/NE
OF BIG ISLAND SPREADS WEST. WINDWARD TERMINALS ON THE BIG ISLAND
AND MAUI WILL BEGIN TO SEE TEMPO MVFR CONDITIONS EARLY THIS
AFTERNOON AND THE REMAINING ISLANDS THIS EVENING. OTHERWISE...THERE
ARE NO AIRMETS IN EFFECT AND VFR CONDITIONS SHOULD PREVAIL.

&&

.MARINE...
WINDS MAY INCREASE TO SMALL CRAFT ADVISORY LEVELS BY SUNDAY OR
SUNDAY EVENING ACROSS THE TYPICALLY WINDIER AREAS AROUND MAUI COUNTY
AND THE BIG ISLAND. SMALL CRAFT ADVISORY CONDITIONS WILL THEN REMAIN
POSSIBLE IN THE TYPICALLY WINDY AREAS THROUGH MUCH OF NEXT WEEK.

A SMALL SSW SWELL MAY PRODUCE A MINOR BUMP ON SOUTH FACING SHORES
TONIGHT INTO SUNDAY. SHORT PERIOD TRADE WIND SWELL WILL CONTINUE
ACROSS EAST FACING SHORES...POSSIBLY INCREASING A BIT EARLY NEXT
WEEK IF TRADES STRENGTHEN. NO SIGNIFICANT NORTH THROUGH WEST SWELLS
ARE EXPECTED THROUGH THE NEXT SEVERAL DAYS. OVERALL...SURF WILL
REMAIN WELL BELOW ADVISORY LEVELS ON ALL SHORES THROUGH THE WEEKEND
AND INTO THE FIRST PART OF NEXT WEEK.

&&

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

&&

$$

DISCUSSION/MARINE...POWELL
AVIATION...EATON









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