000 
FXHW60 PHFO 232021
AFDHFO

HAWAIIAN ISLANDS FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HONOLULU HI
1000 AM HST TUE NOV 23 2004

.SYNOPSIS...
AN UPPER LEVEL LOW IN THE VICINITY OF OAHU AND MOLOKAI WILL KEEP 
THE ISLAND ATMOSPHERE UNSTABLE TODAY...PRODUCING SCATTERED HEAVY 
SHOWERS AND POSSIBLE THUNDERSTORMS WITH HEAVY RAIN. A BROAD SWATCH 
OF MOISTURE OVER AND EAST OF THE BIG ISLAND IS WEAKENING THIS 
MORNING BUT MAY STILL PROMOTE HEAVY RAIN AND THUNDERSTORM 
DEVELOPMENT ON THE BIG ISLAND LATER TODAY AND TONIGHT. THE THREAT OF 
HEAVY RAIN WILL CONTINUE THROUGH THANKSGIVING. WINDS WILL REMAIN 
LIGHT AND VARIABLE.

&&

.DISCUSSION...
A LOW ALOFT HAS BEEN MOVING SOUTH...TOWARD THE ISLANDS OVER THE 
PAST 2 DAYS. THIS LOW IS NOW CENTERED JUST NORTH OF OAHU AND 
MOLOKAI...AND WILL MOVE SOUTHWARD ACROSS THE ISLAND CHAIN TODAY. 
WARM...MOIST TROPICAL MOISTURE MOVING NORTHWARD AROUND THE EASTERN 
FLANK OF THE UPPER LEVEL SYSTEM IS MOVING OVER AND EAST OF THE BIG 
ISLAND THIS MORNING. AS THE UPPER LOW DROPS FARTHER SOUTHWARD... 
EXPECT SOME OF THAT MOISTURE EAST OF THE BIG ISLAND WILL BE PULLED 
WESTWARD AROUND THE LOW. THIS MAY INCREASE SHOWERS AND THUNDERSTORM 
POSSIBILITIES WESTWARD ACROSS THE SMALLER ISLANDS LATER TODAY. 
AFTERNOON HEATING WILL ALSO INCREASE THE CHANCE FOR DEEP 
THUNDERSTORMS AS IT INCREASES THE TEMPERATURE DIFFERENTIAL BETWEEN 
THE SURFACE AIR AND THE COLDER AIR NEAR THE CENTER OF THE UPPER LOW. 

THE LOW ALOFT IS FORECAST REMAIN OVER THE CENTRAL ISLANDS INTO 
TONIGHT...TROUGHING SOUTHEASTWARD BY WEDNESDAY MORNING...AND FINALLY 
REDEVELOPING EAST OF THE BIG ISLAND BY WEDNESDAY NIGHT. AT THE SAME 
TIME...RIDGING WESTWARD OF THE STATE WILL TEND TO CLEAR SHOWERS OUT 
FROM THE SMALLER ISLANDS...AND LEAVING THE BIG ISLAND STILL 
SUSCEPTABLE TO HEAVY RAIN THROUGH FRIDAY. WITH TRADE WINDS EXPECTED 
TO RETURN...WILL LIKELY SEE A CHANGE TO A WET TRADE WIND PATTERN 
OVER THE WEEKEND.

&&

.HFO WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH FOR BIG ISLAND OF HAWAII THROUGH TODAY.
WINTER STORM WATCH FOR BIG ISLAND SUMMITS TODAY THROUGH THANKSGIVING 
DAY. 

$$

FARRELL