Current Conditions
Temp3.2 C
RH13 %
WindESE 27 mph
RoadOpen
Menu of Text Products for the Hawaiian Islands and the Tropical Pacific/Atlantic Oceans:
Narrow the Menu List
Select Time Limit: 12 hours | 24 hours | 48 hours | 72 hours | No time limit
Select Product Type: All | Routine Bulletins/FCSTS | Warnings/Watches/Advisories | HAWN Weather | Tropical | Marine | Aviation | Daily Obs | Special
Hawaiian Islands Synoptic Discussion and Guidance

796
FXHW60 PHFO 231330
AFDHFO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HONOLULU HI
330 AM HST TUE SEP 23 2014

.SYNOPSIS...
INCREASING TRADE WINDS WILL SHIFT CLOUD COVER AND SHOWER ACTIVITY
OVER WINDWARD AND MOUNTAIN AREAS DURING THE NEXT COUPLE OF DAYS.
LEEWARD AREAS WILL REMAIN RATHER DRY...EXCEPT FOR AFTERNOON SHOWERS
DEVELOPING OVER THE KONA COAST. SHOWERS WILL INCREASE STARTING LATE
WEDNESDAY AND INTO THURSDAY AS ENHANCED MOISTURE REACHES THE ISLAND
CHAIN FROM THE NORTH...AND POSSIBLY PERSISTING THROUGH THE UPCOMING
WEEKEND.

&&

.DISCUSSION...
A STRENGTHENING HIGH PRESSURE SYSTEM FAR NNW OF THE ALOHA STATE IS
BRINGING BACK THE TRADES AS PRESSURE GRADIENTS ACROSS THE AREA
BECOME STRONGER. THE TRADES WILL BECOME MODERATE AND GUSTY DURING
THE NEXT COUPLE OF DAYS...AND PERSIST THROUGH THE WEEKEND. THE
TRADES ARE ALSO PROVIDING A RELIEF FROM THE MUGGY AND HUMID
CONDITIONS FROM LAST WEEK. MIMIC AND MODEL MOISTURE ANALYSES SHOW A
DRIER AIRMASS MOVING INTO THE AREA FROM THE E WITH DEW POINTS A FEW
DEGREES LOWER FROM THE VALUES EXPERIENCED DURING THE PAST SEVERAL
DAYS. THIS SYNOPTIC SCENARIO WILL ALSO HELP IN COOLING TEMPERATURES
A LITTLE. HOWEVER...LEEWARD AREAS WILL LIKELY REMAIN SEASONABLY
HOT...HOVERING THE 90 DEGREE MARK THROUGH WED.

THE TRADE WIND PATTERN WILL SHIFT SHOWER ACTIVITY BACK TO WINDWARD
AND MAUKA AREAS...EXCEPT FOR THE TYPICAL AFTERNOON PERIODS OF
CLOUDS AND SHOWERS OVER THE KONA SLOPES. RAINFALL ACCUMULATIONS IN
GENERAL SHOULD REMAIN LIGHT THROUGH WED.

FOR THE SECOND HALF OF THE WEEK...MODELS DEPICT A RATHER WETTER
SCENARIO AS THE AFOREMENTIONED HIGH MOVES TO THE NNE OF THE ISLAND
CHAIN AND PUSHES A REMNANT BAND OF MOISTURE FROM A FORMER FRONTAL
BOUNDARY TOWARDS THE AREA. THIS WILL BRING AN INCREASE IN TRADE
SHOWERS STARTING WED NIGHT AND LASTING PROBABLY THROUGH THE WEEKEND.
THE ACTIVE RAIN PATTERN WILL FAVOR WINDWARD AND MOUNTAIN
AREAS...BUT WITH SOME OF THE LARGER SHOWERS REACHING LEEWARD
LOCATIONS AT TIMES...INCLUDING THE HONOLULU METRO AREA. MODELS ALSO
DEPICT A POSSIBLE MID/UPPER LEVEL TROUGH MOVING NEAR THE ISLAND
CHAIN FROM THE SE ON THE FRI-EARLY SAT TIMEFRAME...WHICH COULD
FURTHER ENERGIZE THE BAND OF MOISTURE AND BRING THE POTENTIAL FOR
PERIODS OF LOCALIZED HEAVY RAIN.

THE FORECAST PACKAGE HAS BEEN UPDATED TO REFLECT A SIGNIFICANT
INCREASE IN POPS FOR THE LATER PART OF THE WEEK...WITH HIGHEST
CHANCES OF RAIN FOCUSED OVER WINDWARD AND MOUNTAIN AREAS. THE
FORECAST HAS NO MENTION OF HEAVY RAINFALL YET...BUT FURTHER UPDATES
MAY INCLUDE SUCH WORDING AS THE DETAILS OF THE EVENT BECOME CLEARER
WITH UPCOMING MODEL RUNS.

&&

.AVIATION...
A BREEZY TRADE WIND PATTERN WILL CONTINUE ACROSS THE STATE TODAY
AND TONIGHT. CLOUDS AND SHOWERS WILL REMAIN FOCUSED PRIMARILY
ACROSS WINDWARD AND MAUKA AREAS...WITH BRIEF MVFR CONDITIONS
OCCURRING IN SHOWERS. WITH THE 12Z LIHUE RAOB AS WELL AS 88D VWP AND
AMDAR SOUNDING DATA ALL SHOWING LOW LEVEL WINDS INCREASING ABOVE 20
KNOTS ACROSS THE AREA...AIRMET TANGO HAS BEEN ISSUED FOR LOW LEVEL
TURBULENCE TO THE LEE OF HIGHER TERRAIN ACROSS ALL ISLANDS.

&&

.MARINE...
STRENGTHENING TRADES ARE BRINGING ADVISORY CONDITIONS ACROSS THE
TYPICALLY WINDIER WATERS AROUND THE BIG ISLAND AND MAUI COUNTY.
THUS...A SMALL CRAFT ADVISORY IS NOW IN EFFECT FOR THOSE MARINE
ZONES VALID UNTIL 6 AM HST WEDNESDAY...AND COULD BE EXTENDED BEYOND
THAT TIME IF NECESSARY. WINDS ACROSS THE NORTHERN COASTAL WATERS MAY
BRIEFLY INCREASE A LITTLE LATE WEDNESDAY AND INTO THURSDAY AS A BAND
OF MOISTURE REACHES THE ALOHA STATE FROM THE NORTH.

SURF WILL REMAIN AROUND BACKGROUND LEVELS THROUGH MUCH OF THE WEEK.
A SLIGHTLY HIGHER SWELL...POSSIBLY UP TO 4 FEET...IS EXPECTED FROM
THE NNE THURSDAY THROUGH SATURDAY. A MODERATE SSW IS ALSO EXPECTED
TO ARRIVE THIS WEEKEND.

&&

.HFO WATCHES/WARNINGS/ADVISORIES...
SMALL CRAFT ADVISORY UNTIL 6 AM HST WEDNESDAY FOR MAALAEA BAY-
PAILOLO CHANNEL-ALENUIHAHA CHANNEL-BIG ISLAND LEEWARD WATERS-BIG
ISLAND SOUTHEAST WATERS.

&&

$$

DISCUSSION/MARINE...REYNES
AVIATION...JACOBSON







Bulletins, Forecasts and Observations are courtesy of Honolulu National Weather Service Forecast Office