Small Craft Advisory 30, NWS Honolulu, HI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HONOLULU HI
1000 AM HST MON JUL 14 2014

.SYNOPSIS...
A WEAK SURFACE TROUGH IS PASSING BY SOUTH OF THE STATE PROVIDING FOR
ENHANCED WINDWARD AND MAUKA SHOWERS AS WELL AS LIGHT WINDS ACROSS
THE AREA. HIGH PRESSURE WILL BE BUILDING IN TO OUR NORTH THIS WEEK
PLACING THE ISLANDS IN A MODERATE TRADE WIND ENVIRONMENT. CLOUDS AND
PASSING SHOWERS WILL CONTINUE TO FAVOR WINDWARD AND MAUKA AREAS. A
LOW ALOFT MAY CAUSE FOR AN INCREASE IN SHOWER ACTIVITY OVER THE
WEEKEND.

&&

.DISCUSSION...
A WEAK SURFACE TROUGH IS IS SEEN ON SATELLITE IMAGERY PASSING BY
JUST TO THE SOUTH OF THE STATE. MOISTURE ASSOCIATED WITH THE TROUGH
IS MOVING ACROSS THE AREA WHICH IS THE CAUSE FOR THE ENHANCED SHOWER
ACTIVITY ACROSS PORTIONS OF THE AREA...MAINLY AFFECTING WINDWARD AND
MAUKA LOCATIONS. THE AIR MASS IS A BIT UNSTABLE OVER THE BIG ISLAND
THUS THERE IS A SLIGHT CHANCE FOR A STRAY THUNDERSTORM TO FORM OVER
THE SLOPES TODAY MAINLY DURING THE AFTERNOON HOURS.

SATELLITE DERIVED PRECIPITABLE WATER VALUES REMAIN HIGH OVER THE
ISLANDS AS WELL AS THE WATERS TO THE EAST. THUS WE EXPECT ENHANCED
WINDWARD AND MAUKA SHOWERS TO CONTINUE INTO WEDNESDAY WITH A DRYING
TREND EXPECTED LATER WEDNESDAY AND THURSDAY. HIGH PRESSURE WILL
BUILDING IN TO OUR NORTH THIS WEEK WITH MODERATE TO BREEZY TRADE
WINDS EXPECTED FOR THE MIDDLE AND LATTER HALF OF THE WEEK.

A MID LEVEL TROUGH IS EXPECTED TO DEVELOP NORTHEAST OF THE STATE
DURING THE MIDDLE OF THE WEEK AND GRADUALLY MOVE WESTWARD ACROSS THE
AREA BY THE WEEKEND. THIS MAY DESTABILIZE THE AIRMASS ACROSS THE
AREA WITH SOME ENHANCEMENT IN SHOWER ACTIVITY POSSIBLE WITH THIS
SCENARIO. HOW MUCH INCREASE IN SHOWERS WE RECEIVE WILL BE HIGHLY
DEPENDENT ON MOISTURE AVAILABILITY.

&&

.MARINE...
WITH THE EXPECTED INCREASE IN TRADE WINDS BEGINNING TONIGHT...SMALL
CRAFT ADVISORY CONDITIONS WILL LIKELY OCCUR OVER THE TYPICALLY WINDY
WATERS AROUND MAUI COUNTY AND THE BIG ISLAND. THESE CONDITIONS WILL
CONTINUE THROUGH THE REST OF THE WEEK.

DATA FROM THE LANAI BUOY HAS BEEN SHOWING THE CURRENT SOUTH SWELL
IS IN LINE WITH WAVE WATCH III DATA WITH SIGNIFICANT WAVE HEIGHTS
OF 3 FEET WITH PERIODS OF 15 TO 17 SECONDS. THIS SWELL WILL LINGER
THROUGH THE MIDDLE OF THE WEEK BEFORE SLOWLY SUBSIDING DURING THE
LATTER PART OF THE WEEK AND ON INTO THE WEEKEND. THE STRENGTHENING
TRADE WINDS THIS WEEK WILL CAUSE AN INCREASE IN SHORT PERIOD CHOPPY
SURF ALONG EAST FACING SHORES.

&&

.AVIATION...
CLOUDS AND SHOWERS MOVING OVER THE WINDWARD PORTIONS OF THE ISLANDS
ARE BRINGING TEMPO OBSCURATION TO THE NORTH THROUGH EAST SECTIONS
OF THE ISLANDS. EXPECTING CONDITIONS TO IMPROVE OVER THE BIG ISLAND
LATER THIS MORNING WHILE CONDITIONS OVER THE SMALLER ISLANDS WILL
LIKELY LINGER INTO THE AFTERNOON.

CONDITIONS REMAIN ON THE UNSTABLE SIDE OVER THE BIG ISLAND...SO THE
CHANCE FOR ISOLATED THUNDERSTORMS REMAINS TODAY...BUT EXPECT
CONDITIONS TO STABILIZE TONIGHT.

&&

.HFO WATCHES/WARNINGS/ADVISORIES...
NONE.

&&

SYNOPSIS/DISCUSSION/MARINE...BURKE
AVIATION....M BALLARD