Heavy Rain in Hawaii, November 8, 2011

AREA FORECAST DISCUSSION...CORRECTED
NATIONAL WEATHER SERVICE HONOLULU HI
1013 AM HST TUE NOV 8 2011

CORRECTED AVIATION

.SYNOPSIS...
AN UPPER LEVEL TROUGH OVER THE STATE WILL KEEP UNSETTLED WEATHER
THROUGH AT LEAST FRIDAY. FOR TODAY...WETTER CONDITIONS AND A HIGHER
CHANCE FOR UNSETTLED WEATHER WILL BE OVER THE BIG ISLAND. SHOWERS
WILL BE FOCUSED ACROSS WINDWARD AND MAUKA AREAS...THOUGH TRADE WINDS
WILL SPREAD SHOWERS TO LEEWARD SECTIONS AT TIMES. STRONG HIGH
PRESSURE PASSING FAR NORTH OF THE STATE WILL CAUSE TRADE WINDS TO
STRENGTHEN FOR THE SECOND HALF OF THE WORK WEEK.

&&

.DISCUSSION...
A COMPLEX WEATHER SITUATION EXISTS OVER THE ISLANDS...FEATURING LOW
LEVEL RIDGING WITH LOCALLY BREEZY TRADES AND A STUBBORN UPPER LEVEL
TROUGH WITH UNSTABLE CONDITIONS ALOFT. FOR TODAY...THE LOW LEVEL
RIDGE...WHICH IS EVIDENT ON THE OVERNIGHT SOUNDINGS AND RECENT
AIRCRAFT DATA...SHOULD HOLD OVER THE SMALLER ISLANDS AND KEEP A LID
ON CONVECTION. EXPECT SHOWERS TO BE FOCUSED OVER WINDWARD AREAS...
WITH A CHANCE OF SHOWERS LEEWARD. WETTER CONDITIONS ARE IN STORE FOR
THE BIG ISLAND AS DEEPER MOISTURE RIDES IN ON THE TRADE WIND FLOW.
IN ADDITION...THE COLDEST TEMPERATURES ALOFT ASSOCIATED WITH THE
UPPER TROUGH AXIS ARE PARKED OVER THE BIG ISLAND. THIS COMBINATION
OF MOISTURE AND INSTABILITY WILL LEAD TO A SLIGHT CHANCE OF
THUNDERSTORMS OVER THE BIG ISLAND AND ADJACENT WATERS. THE SUMMITS
MAY ALSO EXPERIENCE A SNOW SHOWER THIS AFTERNOON. AN UPDATE HAS
BEEN SENT TO REFLECT THIS SCENARIO.

UNSETTLED WEATHER IS POSSIBLE STATE-WIDE TONIGHT INTO WEDNESDAY
MORNING. THE MOISTURE CURRENTLY NEAR THE BIG ISLAND WILL SPREAD
WESTWARD TO THE SMALLER ISLANDS...LIKELY BRINGING AN INCREASE IN
SHOWERS. THE MAIN INCREASE IN RAINFALL WILL BE OVER WINDWARD AND
MAUKA AREAS...THOUGH TRADES WILL CARRY PERIODIC SHOWERS ACROSS
LEEWARD SECTIONS. DURING THIS TIME...AN UPPER LEVEL DISTURBANCE WILL
DROP INTO THE UPPER LEVEL TROUGH AND ERODE THE LOW LEVEL INVERSION.
THIS WILL LEAD TO A SLIGHT CHANCE OF THUNDERSTORMS PRETTY MUCH
ANYWHERE OVERNIGHT.

A BRIEF DRYING PERIOD NEAR THE SURFACE COULD BRING A LULL IN SHOWER
ACTIVITY WEDNESDAY NIGHT AND THURSDAY. THE GFS AND ECMWF BOTH SHOW A
SURGE IN MOISTURE CENTERED AROUND THURSDAY NIGHT THROUGH EARLY
SATURDAY ASSOCIATED WITH THE REMAINS OF A DISSIPATED FRONT AND WILL
BE EXPECTING A GENERALLY WET PATTERN DURING THAT TIME.

AT THE SURFACE...WINDS WILL REMAIN MODERATE TO LOCALLY BREEZY TODAY
WITH AN INCREASE IN STORE WEDNESDAY. HIGH PRESSURE FAR EAST
NORTHEAST OF THE STATE WILL GIVE WAY TO A STRONGER HIGH BUILDING IN
FAR NORTH OF THE STATE TOMORROW. WINDS ARE EXPECTED TO INCREASE ON
WEDNESDAY AS A RESULT AND REMAIN STRONG INTO FRIDAY...EVENTUALLY
WEAKENING OVER THE WEEKEND. THE STRONGER WINDS WILL RESULT IN MORE
PASSING LEEWARD SHOWERS THE SECOND HALF OF THE WEEK...ESPECIALLY
THURSDAY NIGHT AND FRIDAY AS SURFACE MOISTURE REMAINS HIGH.

&&

.AVIATION...
DUE TO MODERATELY STRONG TRADE WINDS...AIRMET TANGO REMAINS IN PLACE
FOR LOW LEVEL TURBULENCE BLW 080...S AND W OF THE TERRAIN ON ALL
ISLANDS. AIRMET SIERRA IS ALSO IN EFFECT FOR EXTENSIVE MT OBSC ALONG
THE N AND E FACING SLOPES OF BIG ISLAND. ALTHOUGH THE LOW LEVEL
INVERSION IS EXPECTED TO WEAKEN OR DISSIPATE ALTOGETHER TONIGHT AND
WEDNESDAY...AIRMET TANGO WILL LIKELY REMAIN IN PLACE DUE TO
INCREASING TRADE WINDS.

WINDWARD TERMINALS WILL SEE A FEW BRIEF PASSING SHRA...WITH MORE
SIGNIFICANT MVFR CIG/SHRA EXPECTED TO AFFECT PHTO INTO THIS
AFTERNOON. TSRA HAS BEEN REPORTED OVER WATERS EAST OF THE BIG ISLAND
IN THE LAST HOUR...AND THE AREA FORECAST HAS BEEN UPDATED TO INCLUDE
THE THREAT OF ISOL IFR CONDITIONS.

&&

.MARINE...
A SMALL CRAFT ADVISORY /SCA/ DUE TO STRONG WINDS IS IN EFFECT FOR
THE TYPICALLY WINDIER WATERS NEAR MAUI COUNTY AND THE BIG ISLAND.
BEGINNING AT 600 PM HST ALL HAWAIIAN CHANNELS WILL BE UNDER THE SCA
AS TRADE WINDS GRADUALLY STRENGTHEN...AND WILL LIKELY INCLUDE ALL
COASTAL WATERS BY WEDNESDAY MORNING.

A NORTHEAST SWELL COMBINED WITH ROUGH...LOCALLY-GENERATED SEAS WILL
LIKELY PRODUCE SURF WELL ABOVE THE ADVISORY LEVEL FOR EAST FACING
AND POSSIBLY NORTH FACING SHORES DURING THE HOLIDAY 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.

SMALL CRAFT ADVISORY FROM 6 PM THIS EVENING TO 6 AM HST
WEDNESDAY FOR KAUAI CHANNEL-KAIWI CHANNEL.

&&

PUBLIC AND MARINE...WROE
AVIATION...BIRCHARD