Heavy Rain in Hawaii, March 21 to 24, 2014

AREA FORECAST DISCUSSION...CORRECTED
NATIONAL WEATHER SERVICE HONOLULU HI
400 AM HST FRI MAR 21 2014

.SYNOPSIS...
HIGH PRESSURE NORTH OF THE ISLANDS WILL MAINTAIN TRADE WINDS THROUGH
NEXT WEEK. A SLIGHT BOOST IN WIND SPEEDS IS EXPECTED IN THE NEXT FEW
DAYS INTO NEXT WEEK. REMNANT MOISTURE FROM AN OLD FRONT WILL BRING
AN INCREASE IN SHOWERS MAINLY TO THE WINDWARD SIDE OF THE BIG ISLAND
AND MAUI FOR THE NEXT FEW DAYS.

&&

.DISCUSSION...
WINDWARD BIG ISLAND AS WELL AS WINDWARD MAUI CONTINUE TO SEE
EXTENSIVE CLOUDS AND SHOWERS EARLY THIS MORNING...AS RESIDUAL
MOISTURE FROM A DISSIPATED FRONT LINGERS. LATEST RADAR IMAGERY
INDICATED THERE ARE LOCALLY HEAVIER SHOWERS EMBEDDED. MOREOVER...
LATEST SATELLITE IMAGERY REVEALED SOME OF THE MOISTURE HAS REACHED
WINDWARD MOLOKAI THIS MORNING. EXPECT THE WET WEATHER TO CONTINUE TO
AFFECT THOSE AREAS TODAY. ELSEWHERE LOW CLOUDS CARRIED BY THE TRADE
WINDS ARE PROVIDING SOME SHOWERS. THESE SHOWERS ARE AFFECTING MAINLY
WINDWARD AND MOUNTAIN AREAS...THOUGH SOME SHOWERS DO REACH THE LEE
AREAS AT TIMES UNDER THE MODERATE TRADE WINDS.

THE SURFACE HIGH PRESSURE THAT IS RESPONSIBLE FOR THE TRADE WINDS IS
EXPECTED TO PERSIST THROUGH THE REST OF THE WEEK INTO EARLY NEXT
WEEK. AS SUCH...THE ISLANDS CAN EXPECT TRADE WIND WEATHER TO
PREVAIL...WITH PASSING SHOWERS AFFECTING MAINLY WINDWARD AND
MOUNTAIN AREAS. WHAT COMPLICATES THE TRADE WIND WEATHER A
LITTLE IN THE NEXT COUPLE OF DAYS IS AN UPPER LEVEL FEATURE THAT IS
EXPECTED TO PASS THE STATE. AN APPROACHING MIDDLE LEVEL TROUGH FROM
THE NORTHWEST WILL PASS OVER THE ISLANDS THROUGH THE WEEKEND. ITS
PASSAGE WILL KEEP AIR MASS UNSTABLE IN THE ISLAND
VICINITY...RESULTING PASSING SHOWERS BEING ENHANCED AT TIMES. THE
AIR MASS IS UNSTABLE ENOUGH FOR DEEPER AFTERNOON CONVECTION TO
DEVELOP OVER THE BIG ISLAND ONCE AGAIN. THEREFORE HAVE MENTIONED A
SLIGHT CHANCE OF THUNDERSTORMS OVER THE INTERIOR AREAS OF THE BIG
ISLAND IN THE AFTERNOON. ATMOSPHERIC CONDITIONS MAY IMPROVE ENOUGH
OVER THE REST OF THE WEEKEND INTO EARLY NEXT WEEK SUCH THAT THE
THREAT OF THUNDERSTORM OVER THE BIG ISLAND WILL JUST BE TODAY. ON
THE OTHER HAND...THE ISLANDS WILL CONTINUE TO SEE ENHANCED SHOWERS
THROUGH WEEKEND INTO EARLY NEXT WEEK.

THE TRADES ARE ALSO EXPECTED TO STRENGTHEN A LITTLE MORE NEXT
WEEK...AS A STRONGER SURFACE HIGH PRESSURE IS EXPECTED TO PASS FAR
NORTH OF THE STATE. AN UPPER LEVEL RIDGE IS ALSO EXPECTED TO MOVE
NEAR THE ISLAND VICINITY BY TUESDAY. THIS SHOULD RESULT IN A MORE
STABLE AIRMASS RETURNING TO THE STATE...AND THEREFORE LIMITING THE
AMOUNT OF PRECIPITATION OVER THE ISLANDS.

&&

.AVIATION...
REMNANTS FROM AN OLD FRONT WITH AREAS OF LIFR CONDS ARE HUNG UP OVER
THE NE FACING SIDE OF THE BIG ISLAND. EXPECT SOME IMPROVEMENT LATER
THIS MORNING WHERE AT THAT POINT...AIRMET SIERRA FOR MTN OBSC...MAY
BE LIFTED.

ON THE OTHER HAND...THESE CLDS AND WEATHER HAVE SETTLE ON TO
WINDWARD MAUI WHERE AIRMET SIERRA FOR MTN OBSC IS LIKELY COMMENCING
WITH THE 16Z PACKAGE.

OTHERWISE...VFR IS THE PREVAILING COND BUT PEPPERED IN WITH BRIEF
MVFR CEILINGS AND VIS ASSOCIATED WITH THE TRADE WIND SHOWERS. THESE
SHOWERS WILL FAVOR THE WINDWARD AND MTN AREAS.

A COUPLE OF THESE SHOWERS MAY STRAY OVER TO THE LEEWARD COMMUNITIES
DURING THE COURSE OF THE DAY.

NO SIGNIFICANT TURB EXPECTED.

&&

.MARINE...
READINGS FROM THE BUOY FAR NORTHWEST SHOWED HIGHER THAN EXPECTED
VALUES EARLY THIS MORNING. THEREFORE THIS INCOMING NORTHWEST SWELL
IS HIGH ENOUGH TO BRING ADVISORY LEVEL SURF FOR NORTH AND WEST
FACING SHORES OF THE WESTERN ISLANDS. A HIGH SURF ADVISORY IS POSTED
UNTIL 4 AM FOR NORTH AND WEST FACING SHORES OF NIIHAU KAUAI OAHU AND
MOLOKAI AND NORTH FACING SHORES OF MAUI. A SMALLER NORTHWEST SWELL
IS DUE ON SUNDAY.

WINDS AROUND THE COASTAL WATERS OF THE ISLANDS WILL REMAIN JUST
UNDER THE SMALL CRAFT LEVELS TODAY...THOUGH COMBINING THE LARGE
INCOMING SWELL...THE RESULTANT SEAS WILL REACH SMALL CRAFT LEVEL
FOR WATERS AROUND KAUAI AND OAHU. THEREFORE A SMALL CRAFT ADVISORY
IS POSTED FOR WATERS AROUND KAUAI AND OAHU THROUGH THIS EVENING. IT
LOOKS LIKE THE WINDS WILL INCREASE ENOUGH THIS EVENING OVER THE
TYPICAL WINDY COASTAL ZONES AROUND MAUI COUNTY AND THE BIG ISLAND TO
WARRANT A SMALL CRAFT ADVISORY AS WELL.

&&

.HFO WATCHES/WARNINGS/ADVISORIES...
HIGH SURF ADVISORY FOR NORTH AND WEST FACING SHORES OF NIIHAU KAUAI
OAHU MOLOKAI AND NORTH FACING SHORES OF MAUI UNTIL 4 AM HST SATURDAY.

SMALL CRAFT ADVISORY UNTIL 10 PM HST THIS EVENING FOR WATERS AROUND
KAUAI AND OAHU.

SMALL CRAFT ADVISORY FROM 6 PM THIS EVENING TO 6 PM HST MONDAY
FOR MAALAEA BAY-PAILOLO CHANNEL-ALENUIHAHA CHANNEL-BIG ISLAND
LEEWARD WATERS-BIG ISLAND SOUTHEAST WATERS.

&&

DISCUSSION/MARINE...HUI
AVIATION...LAU

CORRECTED HEADER FOR AVIATION SECTION