Flash Flood Warning 51, NWS Honolulu, HI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HONOLULU HI
1000 AM HST MON OCT 14 2013

.SYNOPSIS...
A LIGHT BACKGROUND FLOW COMBINED WITH UNSTABLE CONDITIONS WILL
PRODUCE A CONVECTIVE WEATHER PATTERN WITH A CHANCE OF THUNDERSTORMS
THROUGH TOMORROW. SEA BREEZES WILL PRODUCE AFTERNOON CLOUDS...
LOCALLY HEAVY SHOWERS AND POSSIBLE THUNDERSTORMS...WHILE LAND
BREEZES WILL BRING PARTIAL CLEARING OVER THE ISLANDS AT NIGHT. A
MORE STABLE LAND AND SEA BREEZE PATTERN WILL PREVAIL DURING THE
SECOND PART OF THE WEEK...WITH UNSTABLE CONDITIONS POSSIBLE AGAIN
HEADING INTO THE WEEKEND.

&&

.DISCUSSION...
AN UNSTABLE CONVECTIVE PATTERN IS EXPECTED TODAY. A SURFACE TROUGH
NORTH OF THE STATE HAS SIGNIFICANTLY WEAKENED THE TRADE WIND FLOW
AND SHIFTED IT OUT OF THE EAST-SOUTHEAST. DAYTIME SEA BREEZES WILL
EASILY OVERPOWER THIS FLOW...LEADING TO AFTERNOON CLOUD BUILD UPS
OVER ISLAND INTERIORS. MEANWHILE...AN UPPER LEVEL TROUGH PASSING
OVERHEAD WILL DESTABILIZE THE ATMOSPHERE...ALLOWING FOR THE THREAT
OF LOCALLY HEAVY SHOWERS AND THUNDERSTORMS. A SPECIAL WEATHER
STATEMENT HAS BEEN SENT HIGHLIGHTING THE POSSIBILITY FOR FUNNEL
CLOUDS OVER CENTRAL AND LEEWARD OAHU. THAT SAID...THUNDERSTORMS...
SOME STRONG...COULD POP UP JUST ABOUT ANYWHERE ACROSS THE STATE
TODAY...BRINGING LOCALLY HEAVY DOWNPOURS AND LIGHTNING.

SHOWER AND THUNDERSTORM ACTIVITY WILL TAPER OFF DURING THE EVENING
AS SEA BREEZES GIVE WAY TO LAND BREEZES. HOWEVER...WE STILL CANNOT
RULE OUT ISOLATED HEAVY SHOWERS AND THUNDERSTORMS AS THE ATMOSPHERE
WILL REMAIN UNSTABLE WITH THE UPPER LEVEL TROUGH OVERHEAD.

TUESDAY WILL BRING A REPEAT OF THE CONVECTIVE PATTERN UNDER A LIGHT
TRADE WIND FLOW. CHANCES FOR HEAVY SHOWERS AND THUNDERSTORMS WILL
REMAIN.

FOR THE REST OF THE WEEK...THE LONGWAVE PATTERN ACROSS THE PACIFIC
WILL MAINTAIN A RATHER WEAK BACKGROUND FLOW OVER THE STATE WITH
PERIODS OF INSTABILITY. COUNT ON A LAND AND SEA BREEZE PATTERN TO
DOMINATE OVER THE ISLANDS...PRODUCING THE GREATEST CHANCES FOR
CLOUDS AND SHOWERS ACROSS INTERIOR SECTIONS EACH AFTERNOON ALONG
WITH PARTIAL CLEARING AT NIGHT. THE UPPER LEVEL TROUGH MOVING
OVERHEAD NOW WILL WEAKEN ON WEDNESDAY AND THURSDAY...PROBABLY
ELIMINATING THE RISK OF THUNDERSTORMS THOUGH LOCALLY HEAVY SHOWERS
COULD REMAIN A POSSIBILITY. ALTHOUGH THE GFS AND ECMWF DISAGREE ON
THE DETAILS...ANOTHER ROUND OF INSTABILITY IS POSSIBLE FOR FRIDAY
INTO THE WEEKEND.

&&

.AVIATION...
MAINLY VFR PREVAILS OVR LAND AREAS THIS MORNING. SCT SHRA/RA
OFFSHORE WITH TOPS 100-150 WILL PERSIST THRU THE PD. AFTERNOON
TSRA/+RA WITH TOPS AOA FL300 IS EXP BTN 23Z-04Z AGAIN TODAY BECMG
SKC AFT 04Z-06Z. ISOL MVFR/IFR CONDITIONS ARE POSSIBLE...MAINLY OVER
INTERIOR/LEEWARD SECTIONS. OFFSHORE/CSTL ZONES MAY ALSO SEE TSRA.
VFR SHOULD PREVAIL FOR MOST TERMINALS TODAY HOWEVER SOME TSRA MAY
DRIFT OVR INVOF PHNL. WINDS AT THE FIELDS SHOULD PERSIST FROM
PREVAILING SEA BREEZE DIRECTIONS THIS AFTERNOON.

&&

.MARINE...
NO SMALL CRAFT ADVISORY CONDITIONS ARE EXPECTED THROUGH THE WEEK.
THOUGH NORTH SHORE SURF IS DECLINING TODAY...A SERIES OF MOSTLY
MODERATE NORTHWEST SWELLS ARE IN STORE THIS WEEK. THE NEXT SWELL
WILL PEAK TOMORROW...WITH ANOTHER PEAKING DURING THE WEEKEND. THE
LATEST WAVEWATCH III RUN HAS BOOSTED SWELL NUMBERS FOR THE WEEKEND
SWELL. WE WILL HAVE TO MONITOR THE DEVELOPMENT OF THE RESPONSIBLE
LOW OVER THE NEXT COUPLE OF DAYS AS THERE ARE SIGNIFICANT
DIFFERENCES IN THE MODEL DEPICTIONS OF THIS FEATURE.

&&

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

&&

DISCUSSION AND MARINE...WROE
AVIATION...DEJESUS

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE HONOLULU HI
1002 AM HST MON OCT 14 2013

HIZ005-008-010-011-150200-
CENTRAL OAHU-OAHU KOOLAU-OAHU SOUTH SHORE-WAIANAE MOUNTAINS-
1002 AM HST MON OCT 14 2013

WEATHER CONDITIONS WILL BE FAVORABLE FOR THE DEVELOPMENT OF
THUNDERSTORMS WITH POSSIBLE FUNNEL CLOUDS THROUGH 400 PM HST.

IF THUNDERSTORMS OCCUR...SEEK SHELTER TO PROTECT YOURSELF FROM
LIGHTING. IF FUNNEL CLOUDS EXTEND TO THE GROUND...THEY CAN PRODUCE
DANGEROUS WINDS. REMAIN ALERT FOR CHANGING WEATHER CONDITIONS AND
STAY TUNED TO NOAA WEATHER RADIO...OR LOCAL MEDIA SOURCES FOR
FURTHER INFORMATION.

WROE