Flash Flood Warning 54, NWS Honolulu, HI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HONOLULU HI
330 AM HST MON OCT 12 2015

.SYNOPSIS...A SURFACE TROUGH REMAINS NEARLY STATIONARY ACROSS THE
CENTRAL PORTIONS OF THE ISLAND CHAIN AND WILL KEEP WINDS GENERALLY
LIGHT OVER THE NEXT COUPLE OF DAYS. EXPECT SEA BREEZES TO DEVELOP
AND BRING AFTERNOON CLOUDS AND SHOWERS...WITH PERIODS OF LOCALLY
HEAVY RAINFALL POSSIBLE. A FEW THUNDERSTORMS MAY ALSO DEVELOP FROM
THE BIG ISLAND TO OAHU THIS AFTERNOON. STRONGER TRADE WINDS WILL
RETURN BY MID WEEK AS A WEAK FRONT MOVES ACROSS THE ISLANDS TUESDAY
AND WEDNESDAY.

&&

.DISCUSSION...LIGHT TRADES CONTINUE AS A WEAK SFC TROUGH REMAINS
STATIONARY OVER THE CENTRAL PORTIONS OF THE ISLAND CHAIN. THESE
LIGHT WINDS OR EVEN CALM AT TIMES WILL ALLOW FOR DAYTIME SEA BREEZES
AND NIGHTTIME LAND BREEZES TO DEVELOP STATEWIDE DURING THE NEXT
COUPLE OF DAYS.

TODAY...AS SEA BREEZES DEVELOP IN THE AFTERNOON HOURS...CLOUDS AND
SHOWERS WILL FORM OVER LEEWARD AND INTERIOR AREAS OF THE SMALLER
ISLANDS. THE INFLUENCE OF THE AFOREMENTIONED SFC TROUGH MAY PROVIDE
ENOUGH INSTABILITY FOR ISOLATED THUNDERSTORMS...MAINLY OVER LEEWARD
AREAS OF THE BIG ISLAND AND INTERIOR MAUI. SHOWERS MAY LINGER INTO
THE EVENING HOURS...WITH FOCUS SHIFTING TO WINDWARD AND MAUKA AREAS.

A WEAK COLD FRONT IS EXPECTED TO MOVE IN FROM THE NW ON TUE...AND
TRACK E ACROSS THE ISLAND CHAIN THROUGH WED. MODELS SHOW THE PARENT
UPPER LEVEL TROUGH NEARING THE ISLANDS FROM THE N ALSO BY MID WEEK.
SO FAR THE ONLY SIGNIFICANT IMPACTS WITH THIS FRONT/TROUGH SYSTEM
SEEM TO BE A WEAK BAND OF SHOWERS MOVING OVER THE ISLANDS TUE AND
WED.

A HIGH PRESSURE SYSTEM BEHIND THE FRONT WILL PUSH COOLER AND DRIER
NNE WINDS ACROSS THE ALOHA STATE. LEFTOVER MOISTURE UPSTREAM OF THE
ISLANDS WILL GET CAUGHT IN THE TRADE FLOW LATER IN THE
WEEK...BRINGING PERIODS OF ENHANCED SHOWERS FAVORING WINDWARD AND
MOUNTAIN AREAS THROUGH THE REST OF THE WORK WEEK. MODELS ALSO SHOW
ANOTHER FRONTAL BOUNDARY APPROACHING THE ISLANDS FROM THE N LATE
THUS...WHICH MAY AGAIN WEAKEN THE TRADES THROUGH THE UPCOMING
WEEKEND.

AT 11 PM HST SUN...TROPICAL STORM NORA WAS LOCATED ABOUT 855 MILES
ESE OF HILO HAWAII...MOVING WNW AT 8 MPH. PLEASE VISIT THE CENTRAL
PACIFIC HURRICANE CENTER WEBSITE AT WWW.WEATHER.GOV/CPHC FOR THE
MOST RECENT BULLETINS REGARDING THE PROGRESS OF NORA.

&&

.AVIATION... A WEAK SURFACE TROUGH NEAR OAHU HAS DISRUPTED TRADE
WIND FLOW OVER THE STATE OF HAWAII ENOUGH TO ALLOW LAND BREEZES TO
PREDOMINATE MOST LEEWARD AREAS OVERNIGHT. THESE WEAK LAND BREEZES
WILL BE REPLACED BY LIGHT SEA BREEZES MOST OF THIS AFTERNOON. A DEEP
PLUME OF MOISTURE OVER THE CENTRAL ISLANDS WILL FUEL AFTERNOON AND
EVENING CONVECTION. PERIODS OF HEAVY RAIN AND ISOLATED THUNDERSTORMS
ARE POSSIBLE THIS AFTERNOON AND EVENING FROM OAHU TO THE BIG ISLAND.

TRADE WINDS MEANWHILE WILL PREVAIL OVER KAUAI WHERE AN AIRMET FOR
MTN OBSC REMAINS IN EFFECT. THIS AIRMET WILL LIKELY BE CANCELED THIS
AFTERNOON AS THE SURFACE TROUGH MENTIONED ABOVE SHIFTS SLOWLY
WESTWARD OVER KAUAI.

&&

.MARINE... ALTHOUGH SOME OF THE CHANNELS ARE EXPERIENCING BREEZY
PERIODS...WINDS AND SEAS ARE EXPECTED TO REMAIN BELOW SMALL CRAFT
ADVISORY /SCA/ LEVELS THROUGH EARLY NEXT WEEK. SOME COASTAL ZONES IN
THE WESTERN PART OF THE STATE MAY SEE SCA WINDS TUESDAY AND
WEDNESDAY ALONG A PASSING COLD FRONT.

MODERATE NORTHWEST SWELLS WILL CONTINUE FOR THE NEXT SEVERAL
DAYS...BUT SURF FROM THESE SWELLS SHOULD REMAIN BELOW ADVISORY
LEVELS.

&&

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

&&

DISCUSSION/MARINE...REYNES
AVIATION...BEDAL