High Wind Warning 6, NWS Honolulu, HI

000 
WWHW70 PHFO 250135
NPWHFO

URGENT - WEATHER MESSAGE
NATIONAL WEATHER SERVICE HONOLULU HI
335 PM HST FRI APR 24 2009

...THE HIGH WIND WARNING HAS BEEN DOWNGRADED TO A WIND ADVISORY...

.STRONG WEST-SOUTHWESTERLY WINDS HAVE DECREASED SOMEWHAT BUT ARE
STILL BLOWING AS THE UPPER LEVEL TROUGH MOVES FARTHER EAST OF THE
STATE.

HIZ028-251445-
/O.CAN.PHFO.HW.W.0006.000000T0000Z-090425T2000Z/
/O.NEW.PHFO.WI.Y.0023.090425T0135Z-090426T0400Z/
BIG ISLAND SUMMITS-
335 PM HST FRI APR 24 2009

...WIND ADVISORY IN EFFECT UNTIL 6 PM HST SATURDAY...
...HIGH WIND WARNING IS CANCELLED...

THE NATIONAL WEATHER SERVICE IN HONOLULU HAS ISSUED A WIND
ADVISORY...WHICH IS IN EFFECT UNTIL 6 PM HST SATURDAY. THE HIGH
WIND WARNING HAS BEEN CANCELED. 

EXPECT WINDS OF 20 TO 30 MPH WITH HIGHER GUSTS THROUGH SATURDAY. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A WIND ADVISORY MEANS THAT WINDS OF 30 MPH ARE EXPECTED. WINDS
THIS STRONG CAN MAKE DRIVING DIFFICULT...ESPECIALLY FOR HIGH
PROFILE VEHICLES. USE EXTRA CAUTION.

&&

$$

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HONOLULU HI
400 AM HST FRI APR 24 2009

.SYNOPSIS...
AN UPPER LEVEL DISTURBANCE COMBINED WITH ABUNDANT LOW-LEVEL MOISTURE
WILL BRING THE THREAT OF LOCALLY HEAVY RAIN AND THUNDERSTORMS TO
MAUI COUNTY AND THE BIG ISLAND TODAY. MAINLY SCATTERED SHOWERS WILL
AFFECT KAUAI AND OAHU. LIGHT TO MODERATE NORTHEAST WINDS WILL
CONTINUE IN THE VICINITY OF THE SMALLER ISLANDS THROUGH THIS
WEEKEND...WITH MAINLY LIGHT AND VARIABLE WINDS ACROSS THE LOWER
ELEVATIONS OF THE BIG ISLAND. THE THREAT OF HEAVY SHOWERS WILL
DIMINISH ACROSS THE ENTIRE STATE THIS WEEKEND.

&&

.DISCUSSION...
THE WEAK PRESSURE GRADIENT BETWEEN A SURFACE RIDGE LOCATED ABOUT 300
MILES NORTHEAST OF OAHU AND A WEAK EAST NORTHEAST TO WEST SOUTHWEST
ORIENTED SURFACE TROUGH LOCATED JUST SOUTHEAST OF THE BIG ISLAND
CONTINUES TO PROVIDE THE SMALLER ISLANDS WITH LOW-LEVEL LIGHT TO
MODERATE NORTHEASTERLY WINDS EARLY THIS EVENING. SURFACE WINDS NEAR
THE TROUGH IN THE VICINITY OF THE BIG ISLAND REMAIN LIGHT AND
VARIABLE AT THE LOWER ELEVATIONS.

FROM OAHU EASTWARD...THE AIR FLOW SEVERAL THOUSAND FEET ABOVE THE
SURFACE REMAINS FROM THE WEST SOUTHWEST. AS A RESULT...MOST OF THE
INDIVIDUAL MID-LEVEL CLOUDS AND SHOWERS ARE MOVING ALONG WITH THIS
STEERING FLOW.

IN THE UPPER LEVELS...THE AXIS OF A SHARP UPPER TROPOSPHERIC TROUGH
EXTENDS FROM AN UPPER LEVEL LOW NEAR 30N 156W THROUGH A POINT NEAR
KAUAI. THE TROUGH ALOFT HAS BEEN PROPAGATING TOWARD THE EAST
SOUTHEAST AT ABOUT 30 MPH. THE COLD POOL OF AIR ASSOCIATED WITH THE
TROUGH COMBINED WITH THE DYNAMIC LIFT AHEAD OF THE TROUGH WILL KEEP
THE ATMOSPHERE UNSTABLE ACROSS THE EASTERN END OF THE STATE TODAY.

THE LATEST NAM...GFS AND ECMWF MODEL RUNS CONTINUE TO FOCUS THE BEST
CHANCE FOR HEAVY SHOWERS OVER THE BIG ISLAND AND THE ISLANDS OF MAUI
COUNTY TODAY.T HE UNSTABLE ATMOSPHERIC CONDITIONS PRODUCED BY THE
UPPER LEVEL TROUGH ALONG WITH AMPLE LOW- AND MID-LEVEL MOISTURE WILL
MAINTAIN THE THREAT OF LOCALLY HEAVY RAINFALL AND ISOLATED
THUNDERSTORMS ACROSS THE ISLANDS OF MAUI COUNTY AND THE BIG ISLAND
TODAY. THESE INGREDIENTS WILL KEEP THE THREAT OF FLASH FLOODING...
WHICH MEANS THE FLASH FLOOD WATCH WILL REMAIN IN EFFECT FOR MAUI
COUNTY AND THE BIG ISLAND. BY TONIGHT...THE TROUGH ALOFT IS EXPECTED
TO PASS EAST OF THE STATE AS THE UPPER LEVEL LOW REMAINS TO THE
NORTH. THIS SHOULD DIMINISH THE THREAT FOR HEAVY RAIN THIS WEEKEND.

SOME EXAMPLES OF THE LARGEST RAINFALL TOTALS BY ISLAND ACROSS THE
STATE FOR THE 12 HOUR PERIOD AT 200 AM HST THIS MORNING INCLUDE...
0.03 INCHES AT MOUNT WAIALEALE AND MAKAHA RIDGE ON KAUAI...2.50
INCHES AT MAUNAWILI ON OAHU...0.84 INCHES AT MAKAPULAPAI ON
MOLOKAI...0.30 INCHES AT THE LANAI 1 GAGE ON LANAI...5.95 INCHES AT
WEST WAILUAIKI ON MAUI...2.20 INCHES AT LAUPAHOEHOE ON THE BIG
ISLAND.

THE COLD AIR ALOFT ACCOMPANYING THE TROUGH IS RESULTING IN BELOW
FREEZING TEMPERATURES ON THE SUMMITS ON THE BIG ISLAND. TEMPERATURES
ON PARTS OF HALEAKALA ARE ALSO HOVERING JUST ABOVE FREEZING. THE
COLD TEMPERATURES...UNSTABLE ATMOSPHERE...AND INCREASED MOISTURE HAS
PROMPTED THE ISSUANCE OF A WINTER WEATHER ADVISORY FOR THE SUMMITS
OF MAUNA LOA AND MAUNA KEA ON THE BIG ISLAND AND HALEAKALA SUMMIT ON
MAUI. STRONG WINDS AT THE UPPER ELEVATIONS OF THE BIG ISLAND HAVE
ALSO RESULTED IN THE CONTINUATION OF THE WIND ADVISORY FOR THE BIG
ISLAND SUMMITS.

LOOKING AT THE EXTENDED FORECAST THROUGH THE MIDDLE OF NEXT WEEK...
THE GFS AND ECMWF MODELS CONTINUE TO OFFER WIDELY DIFFERING
SOLUTIONS. EACH OF THE MODELS IS ALSO CHANGING SIGNIFICANTLY FROM
RUN TO RUN. THE LATEST RUN OF THE ECMWF BRINGS A SURFACE LOW
NORTHEAST OF THE STATE BY THURSDAY...WHILE THE GFS HAS A MUCH DEEPER
SURFACE LOW DUE NORTH OF KAUAI TUESDAY NIGHT. WITH THE WIDELY
VARYING SOLUTIONS...THE FORECAST OF LIGHT TRADE WINDS WITH WINDWARD
AND MAUKA SHOWERS WILL REMAIN IN EFFECT FOR THE MIDDLE OF NEXT WEEK
UNTIL THE MODELS REACH A BETTER CONSENSUS.

&&

.MARINE...
THE NORTH NORTHEAST SWELL CONTINUES TO DECREASE THIS MORNING
ACCORDING TO THE LATEST REPORTS FROM THE MOKAPU BUOY. THIS SWELL
WILL CONTINUE TO GRADUALLY DIMINISH TODAY. WINDS AND SEAS WILL
LIKELY BE RATHER BENIGN ACROSS THE HAWAIIAN COASTAL WATERS THIS
WEEKEND...AFTER THE THREAT OF HEAVY DOWNPOURS AND ISOLATED
THUNDERSTORMS SHIFTS EAST OF THE AREA LATER TONIGHT.

&&

.HFO WATCHES/WARNINGS/ADVISORIES...
.FLASH FLOOD WATCH THROUGH THIS AFTERNOON FOR MOLOKAI...LANAI
KAHOOLAWE...MAUI AND THE BIG ISLAND.

WINTER WEATHER ADVISORY UNTIL 600 PM HST THIS EVENING FOR THE BIG
ISLAND SUMMITS AND HALEAKALA SUMMIT.

WIND ADVISORY UNTIL 600 PM HST THIS EVENING FOR BIG ISLAND SUMMITS.

&&

HOUSTON