Wednesday, July 23, 2014 596-SURF , 596-WAVE , 922-BONG , 638-RUSH , 572-SURF(MAUI) , 241-SURF (KAUAI) , 324-RUSH (BIG ISLAND)
   
Text Size
Login
off 2/20/14; off 3/27. on 4/4. on 7/20/14
Banner
Banner

000
FXHW60 PHFO 220200
AFDHFO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HONOLULU HI
400 PM HST MON JUL 21 2014

.SYNOPSIS...
MOIST...HUMID...AND SOMEWHAT UNSTABLE CONDITIONS WILL CONTINUE
THROUGH TONIGHT...WITH SPOTTY HEAVY SHOWERS AND THUNDERSTORMS
POSSIBLE NEAR AND AROUND OAHU AND KAUAI. DRIER...LESS HUMID...AND
INCREASINGLY STABLE TRADE WIND WEATHER WILL BUILD OVER THE ISLANDS
LATER TUESDAY AND WEDNESDAY.

&&

.DISCUSSION...
THUNDERSTORMS HAVE BEEN FIRING ABOUT 100 MILES OR SO TO THE
NORTHWEST AND NORTH OF THE ISLANDS TODAY...BUT ASIDE FROM A FEW
HEAVY DOWNPOURS ON OAHU...SHOWER ACTIVITY ON LAND HAS BEEN
SURPRISINGLY MODEST. AN UPPER LEVEL LOW IS SITTING 700 MILES
NORTHWEST OF KAUAI...PUTTING THE WESTERN END OF THE STATE UNDER AN
UNSTABLE FLOW ALOFT. THUNDERSTORMS HAVE BEEN FOCUSED ALONG AND JUST
EAST OF A PAIR OF LOW LEVEL TROUGHS...ONE NORTHWEST OF KAUAI AND
THE OTHER PASSING A COUPLE HUNDRED MILES NORTH OF MAUI. THIS HAS
BEEN STARVING THE ISLANDS OF ADDITIONAL LOW LEVEL MOISTURE NEEDED TO
FUEL WIDESPREAD HEAVY SHOWERS AND THUNDERSTORMS...EVEN THOUGH WE ARE
SWEATING UNDER HUMID CONDITIONS FEATURING DEW POINTS IN THE VERY
HIGH MID 70S.

A CHANCE FOR HEAVY FLOODING RAINFALL WILL HANG ON FOR THE WESTERN
END OF THE STATE TONIGHT. THE WEAK LOW LEVEL TROUGH NOW NORTH OF
MAUI
WILL PASS OVER AND JUST NORTH OF THE ISLANDS TONIGHT IN THE EASTERLY
TRADE WIND FLOW. AS THE MOISTURE ASSOCIATED WITH THE TROUGH COMES
IN...EXPECT AN UPTICK IN WINDWARD FOCUSED SHOWERS. THE UPPER LEVEL
LOW WILL BE WEAKENING...BUT THE GFS AND ECMWF SHOW ONE LAST
SHORTWAVE ALOFT PASSING OVER THE WESTERN END OF THE ISLAND CHAIN. AS
A RESULT...WE HAVE ADDED HEAVY SHOWER WORDING AND THUNDERSTORM
CHANCES FOR KAUAI AND OAHU...AND THE FLASH FLOOD WATCH HAS BEEN
EXTENDED TO COVER THESE ISLANDS TONIGHT. THE GREATEST RISK FOR
FLOODING WILL BE ACROSS WINDWARD AREAS.

THE THREAT FOR HEAVY RAINFALL WILL DIMINISH GREATLY ON TUESDAY. A
MOIST AND HUMID AIR MASS WILL KEEP SHOWER CHANCES RELATIVELY HIGH...
MAINLY ACROSS WINDWARD SLOPES...BUT LEEWARD POPS WILL REMAIN
SOMEWHAT INCREASED. EVEN THOUGH TRADE WINDS WILL BE A BIT STRONGER
THAN TODAY...HUMID CONDITIONS WILL PREVAIL THROUGH MUCH OF THE DAY
AS DEW POINTS HOVER IN THE LOW TO MID 70/S.

DRIER...LESS HUMID...AND INCREASINGLY STABLE TRADE WIND WEATHER
WILL BUILD OVER THE STATE LATE TUESDAY AND WEDNESDAY. MID TO UPPER
LEVEL RIDGING WILL GRADUALLY BUILD...CREATING A TYPICAL SUMMER TIME
INVERSION AROUND 6000 TO 8000 FT THAT WILL STABILIZE THE ATMOSPHERE.
TRADE WINDS WILL PICK UP A NOTCH AS A 1032 MB HIGH REMAINS PARKED
ABOUT 1400 MILES NORTH OF THE STATE. THIS WILL PATTERN WILL FOCUS
CLOUDS AND MODEST SHOWERS OVER WINDWARD SLOPES. LEEWARD AREAS WILL
BE RATHER DRY...WITH THE EXCEPTION OF THE BIG ISLAND SLOPES WHERE
AFTERNOON CLOUDS AND SHOWERS WILL DEVELOP.

IN THE EXTENDED...TRADE WINDS SHOULD DROP SLIGHTLY FOR THE WEEKEND.
MODELS HAVE BEEN HINTING AT AN INCREASE IN MOISTURE WITHIN THE TRADE
WIND FLOW ON SUNDAY AND MONDAY. UNCERTAINTY REMAINS HIGH.

&&

.MARINE...
THUNDERSTORMS CONTINUE TO SKIRT COASTAL WATERS N OF THE SMALLER
ISLANDS THIS AFTERNOON. A SLIGHT CHANCE OF THUNDERSTORMS HAS BEEN
ADDED AROUND KAUAI AND OAHU OVERNIGHT...BUT CHANCES ARE LOW.

TRADE WINDS ARE DOWN FROM YESTERDAY...BUT EXPECT AN INCREASE AGAIN
TONIGHT INTO WEDNESDAY. A SMALL CRAFT ADVISORY /SCA/ HAS BEEN ISSUED
AHEAD OF THE INCREASE FOR THE TYPICALLY WINDY LOCATIONS AROUND THE
BIG ISLAND AND MAUI. THE SCA THEN EXPANDS TO INCLUDE THE KAIWI
CHANNEL ON TUESDAY. TRADES SHOULD DROP A NOTCH ON FRIDAY WITH BORDER
LINE SCA CONDITIONS DUE IN THE TYPICALLY WINDY AREAS FOR THE WEEKEND.

NO SIGNIFICANT SWELLS ARE SEEN FOR THE UPCOMING WEEK. THE BIGGEST
SURF WILL FROM TRADE WIND SWELL ALONG EAST FACING SHORES.

&&

.AVIATION...
AN AIRMET FOR MOUNTAIN OBSCURATION IS IN EFFECT FOR N THRU E
SECTIONS OF ALL ISLANDS AND CAN BE EXPECTED TO CONTINUE OVERNIGHT.
THICKER HIGHER CLOUDS CONTINUE TO STREAM OVER BIG ISLAND THROUGH
MAUI. TEMPO LIGHT ICE RIME MAY OCCUR IN CLOUDS BETWEEN FL200 AND
FL250.

VFR CONDITIONS PREVAIL AT MOST ISLAND TERMINALS...WITH THE
EXCEPTION OF PHNY. HAVE WINDWARD TERMINALS ON BIG ISLAND AND MAUI
COUNTY WILL LIKELY EXPERIENCE PERIODS OF TEMPO MVFR THROUGHOUT THE
NIGHT...WHILE WINDWARD OAHU AND KAUAI TERMINALS WILL LIKELY
EXPERIENCE TEMPO MVFR WITH ISOL IFR THROUGH THE NIGHT. THE SLIGHT
CHANCE OF THUNDERSTORMS REMAINS FOR KAUAI AND OAHU.

&&

.HFO WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH THROUGH 6 AM HST TUESDAY FOR OAHU...KAUAI... AND
NIIHAU.

SMALL CRAFT ADVISORY FROM 6 PM HST THIS EVENING TO 6 PM HST THURSDAY
FOR PAILOLO AND ALENUIHAHA CHANNELS AND BIG ISLAND LEEWARD WATERS.

SMALL CRAFT ADVISORY FROM 6 AM HST TO 6 PM HST THURSDAY FOR KAIWI
CHANNEL...MAALAEA BAY AND BIG ISLAND SOUTHEAST WATERS.

&&

$$

PUBLIC AND MARINE...WROE
AVIATION...EATON



The Weather Prediction Center

College Park, MD

Hawaii Extended Forecast Discussion




Hawaii Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
645 AM EDT Tue Jul 22 2014

Valid 00Z Wed Jul 23 2014 - 00Z Wed Jul 30 2014


The models indicate that there will still be some moisture
backwash in the wake of Wali through Wednesday night. After that,
Hawai'i will remain vulnerable to minor easterly waves which will
disrupt the trades from time to time. The 00Z/22 high-resolution
ECMWF shows a more substantial tropical wave passing to the south
of the state early next week. Will have to keep an eye on that
system. Rainfall during the next week should be on the order of a
tenth to a quarter of an inch statewide, with several inches
possible in the favored terrain--particularly the western side of
the Big Island.


Cisco





Last Updated: 645 AM EDT Tue Jul 22 2014




Banner
Banner
Banner
Banner
Banner
Banner
Banner
Banner
Banner
Banner
Banner
Banner
Banner
Banner
Banner
Banner

Login Form