Heavy Rain in Hawaii, February 7, 2013

AREA FORECAST DISCUSSION...CORRECTED WWA SECTION
NATIONAL WEATHER SERVICE HONOLULU HI
847 PM HST WED FEB 6 2013

.SYNOPSIS...
ENHANCED SHOWER ACTIVITY WILL CONTINUE THROUGH THURSDAY MORNING AS
AN UPPER LEVEL DISTURBANCE PASSES OVER THE STATE OVERNIGHT. THE BIG
ISLAND AND MAUI MAY SEE BRIEFLY HEAVY SHOWERS ACROSS WINDWARD
AREAS...WHILE LOCALLY BREEZY TRADE WINDS CAUSE SOME SHOWERS TO PASS
OVER LEEWARD SECTIONS OF THE SMALLER ISLANDS AT TIMES. TRADE WINDS
WILL GRADUALLY DECREASE A NOTCH FRIDAY THEN PICK BACK UP AGAIN
LATER EARLY NEXT WEEK. ANOTHER UPPER LEVEL DISTURBANCE MAY BRING
ENHANCED SHOWERS TO THE ISLANDS DURING THE WEEKEND.

&&

.DISCUSSION...
PASSING LOW CLOUDS AND SHOWERS CONTINUE TO AFFECT THE ISLANDS THIS
EVENING...ESPECIALLY OVER THE WINDWARD AND MOUNTAIN AREAS. THESE
SHOWERS MAY BE HEAVIER AT TIMES...AS THE AIR MASS IS SOMEWHAT
UNSTABLE DUE TO THE PASSING OF AN UPPER LEVEL TROUGH OVER THE
ISLANDS. LATEST SATELLITE IMAGERY REVEALS A SLIGHT DECREASE IN THE
LOW CLOUDS COVERAGE OVER THE SMALLER ISLANDS THIS EVENING...THOUGH
WINDWARD AND MOUNTAIN AREAS WILL PROBABLY REMAIN MORE CLOUDY AND
RAINY UNDER THE TRADE WINDS. THERE IS A MORE ORGANIZED BAND OF LOW
CLOUDS JUST EAST OF THE BIG ISLAND THIS EVENING...AND THESE LOW
CLOUDS WILL DEFINITELY BRING MORE MEASURABLE PRECIPITATION TO THE
WINDWARD AND UPSLOPE AREAS. FURTHERMORE...MOISTURE ASSOCIATED WITH
THESE LOW CLOUDS WILL ALSO BE DEEP ENOUGH TO REACH THE SUMMITS OF
THE BIG ISLANDS. WITH COLD TEMPERATURES AT THE SUMMITS...FREEZING
RAIN SHOWERS ARE EXPECTED FOR THE REST OF TONIGHT INTO EARLY
THURSDAY MORNING. A WINTER WEATHER ADVISORY REMAINS IN EFFECT FOR
THE SUMMITS OF THE BIG ISLAND UNTIL EARLY THURSDAY MORNING.

A STRONG SURFACE HIGH PRESSURE FAR NORTHEAST OF THE ISLANDS IS
PROVIDING BREEZY TRADE WINDS TO THE STATE THIS EVENING. THIS HIGH IS
TRACKING FURTHER EAST OVERNIGHT INTO THURSDAY. HENCE TRADE WINDS
WILL BE ON A SLOW DECLINE IN TIME. DRIER TRADE WIND WEATHER WILL
RETURN TO THE ISLANDS LATER THURSDAY...AS THE UPPER LEVEL TROUGH
EXITS EAST OF THE STATE. LOOK FOR A DECREASE IN SHOWER ACTIVITY
THURSDAY...WITH TRADE WINDS GRADUALLY EASING AS WELL.

A FRONTAL SYSTEM FROM THE NORTHWEST WILL APPROACH THE ISLANDS
FRIDAY...RESULTING IN THE FURTHER DECREASE OF TRADE WINDS OVER THE
STATE. THIS FRONT WILL WEAKEN INTO A SHEAR LINE AS IT MOVES NEAR THE
ISLANDS SATURDAY. FORECAST MODELS STILL EXHIBIT DIFFERENCES
CONCERNING HOW MUCH WINDS THE ISLANDS MAY EXPERIENCE...AS ONE MODEL
HAS THIS SHEAR LINE ADVANCING THROUGH THE STATE SATURDAY INTO
SUNDAY WHILE THE OTHER ONE HAS IT STALLED NEAR KAUAI. SHALL STAY
WITH THE CURRENT FORECAST...WHICH IS IN LINE WITH THE STALLED SHEAR
LINE. REGARDLESS...THIS FRONT WILL DISSIPATE EARLY NEXT WEEK...WITH
STRONGER TRADE WINDS BUILDING OVER THE STATE. ANOTHER UPPER LEVEL
DISTURBANCE MAY MOVE NEAR THE ISLANDS EARLY NEXT WEEK...THOUGH THERE
IS ALSO DISCREPANCY ON HOW STRONG THIS DISTURBANCE WILL BE.

&&

.MARINE...
THE SMALL CRAFT ADVISORY /SCA/ REMAINS IN EFFECT FOR THE TYPICALLY
WINDIER WATERS AROUND THE BIG ISLAND AND MAUI OVERNIGHT AND HAS BEEN
EXTENDED THROUGH THURSDAY EVENING AS THE STRONGER WINDS MAY LINGER.

AN SCA WILL LIKELY BE NEEDED AGAIN AS EARLY AS FRIDAY NIGHT DUE TO
HAZARDOUS SEAS FROM THE BUILDING NORTHWEST SWELL.
MEANWHILE...INCREASING TRADE WINDS WILL LIKELY BRING SMALL CRAFT
CONDITIONS FOR THE TYPICALLY WINDY WATERS POSSIBLY SATURDAY NIGHT OR
SUNDAY. THE SMALL CRAFT CONDITIONS WILL PROBABLY SPREAD TO THE REST
OF THE COASTAL WATERS EARLY NEXT WEEK.

NORTHWEST SWELLS WILL MAINTAIN SMALL TO MODERATE SURF ALONG NORTH
AND WEST FACING SHORES OF MOST OF THE SMALLER ISLANDS THROUGH
THURSDAY. A LONG-PERIOD NORTHWEST SWELL BUILDING THURSDAY NIGHT AND
FRIDAY WILL BRING NEAR WARNING LEVEL SURF ALONG NORTH AND WEST
FACING SHORES OF MOST OF THE SMALLER ISLANDS STARTING FRIDAY NIGHT.
THIS LARGE SWELL WILL PERSIST THROUGH THE WEEKEND. SURF MAY ALSO
APPROACH THE HIGH SURF ADVISORY THRESHOLD ALONG WEST FACING SHORES
OF THE BIG ISLAND FRIDAY NIGHT.

&&

.AVIATION...
SHRA/RA/BR WILL PRODUCE MVFR CONDITIONS ALONG WINDWARD SECTIONS
THROUGH THE PERIOD. AIRMET SIERRA FOR MT OBSC FOR WINDWARD/N THRU E
SECTIONS WILL REMAIN IN EFFECT...POSSIBLY ENDG SOMETIME AFT 07/1600Z
TOMORROW MORNING. THE TAF SITES WILL BE MAINLY VFR...HOWEVER
WINDWARD AND ELEVATED FIELDS FROM OAHU EWD WILL SEE FREQUENT MVFR
CIGS AND IFR VIS THRU AT LEAST 07/1600Z.

AIRMET TANGO REMAINS IN EFFECT FOR TURB ALF BTN FL200-FL400 DUE TO
THE STRONG JET WITH WND WSW 80-115KT. THE AIRMET WILL LIKELY LAST
FOR THE NEXT 24 HR.

&&

.HFO WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY FOR THE BIG ISLAND SUMMITS UNTIL 6 AM HST
THURSDAY.

SMALL CRAFT ADVISORY UNTIL 6 PM THURSDAY FOR MAALAEA BAY...PAILOLO
AND ALENUIHAHA CHANNELS...AND WATERS SOUTH OF THE BIG ISLAND.

&&

PUBLIC/MARINE...HUI
AVIATION...DEJESUS