Wednesday, April 23, 2014 596-SURF , 596-WAVE , 922-BONG , 638-RUSH , 572-SURF(MAUI) , 241-SURF (KAUAI) , 324-RUSH (BIG ISLAND)
   
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2.3.14 9am. On 4/22
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000
FXHW60 PHFO 230152
AFDHFO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HONOLULU HI
400 PM HST TUE APR 22 2014

.SYNOPSIS...
STRONG RIDGING NORTH OF THE STATE WILL DRIVE BREEZY AND GUSTY TRADE
WINDS THROUGH AT LEAST FRIDAY. SHOWER ACTIVITY WILL BE DOWN FROM
YESTERDAY...THOUGH WINDWARD RAINFALL WILL CONTINUE TO BE BLOWN OVER
TO LEEWARD AREAS AT TIMES...ESPECIALLY ON THURSDAY. TRADE WINDS WILL
DECLINE LATE SATURDAY INTO EARLY NEXT WEEK WHILE SHOWERS REMAIN
FOCUSED OVER WINDWARD SLOPES.

&&

.DISCUSSION...
BREEZY AND GUSTY TRADE WINDS WILL PERSIST THROUGH THE WORK WEEK. A
1029 MB HIGH HAS BEEN PUSHED TO ABOUT 1200 MILES NORTHEAST OF THE
ISLANDS BY A NORTH PACIFIC FRONT. THE LOCAL PRESSURE GRADIENT AND
THE TRADES ARE DOWN SLIGHTLY SINCE THIS TIME YESTERDAY WHEN THE HIGH
WAS DUE NORTH OF THE STATE...AND THE WIND ADVISORY HAS BEEN
CANCELLED FOR PARTS OF THE BIG ISLAND. HOWEVER...STRONG RIDGING WILL
HOLD BETWEEN 30N AND 33N THROUGH AT LEAST FRIDAY...KEEPING THE
TRADE WINDS BREEZY AND GUSTY.

STRONG MID LEVEL RIDGING WILL REMAIN IN PLACE THROUGH THE WORK
WEEK...MAINTAINING STABLE CONDITIONS AND ENHANCING WIND GUSTS OVER
AND DOWNWIND OF TERRAIN. THE INVERSION WAS DETECTED BETWEEN 3500 AND
6000 FT BY THE AFTERNOON SOUNDINGS AND AIRCRAFT DATA...AND EVEN
THOUGH WINDS ARE DECLINING AT 850 MB...THE PRESENCE OF THE LOW
INVERSION COULD STILL LEAD A GOOD AMOUNT OF GUSTS IN THE 30/S AS
WELL AS LOCALIZED GUSTS OVER 40 MPH. THE GFS AND ECMWF ARE HINTING
AT ANOTHER INCREASE IN 850 MB WINDS LATE THURSDAY AS ANOTHER SURFACE
HIGH PASSES NORTH OF THE STATE...AND ANOTHER ROUND OF LOCALIZED WIND
ADVISORIES MAY BE NEEDED.

TYPICAL WINDWARD SHOWER ACTIVITY IS EXPECTED THROUGH MUCH OF THE
WEEK WITH AN UPTICK IN MOISTURE LIKELY ON THURSDAY. CIMSS SATELLITE
DERIVED PRECIPITABLE WATER /PW/ PRODUCT CLEARLY SHOWS PW VALUES
AROUND A SEASONABLE 1.1 INCHES FILTERING IN FROM THE EAST. THUS...
EXPECT TYPICAL WINDWARD RAINFALL WITH ONLY BRIEF ISOLATED SHOWERS
BEING CARRIED TO LEEWARD AREAS. WE WILL LIKELY SEE ANOTHER INCREASE
IN RAINFALL ON THURSDAY AS A SHOWER BAND PASSES THROUGH. AT THIS
TIME...NO OTHER ORGANIZED AREA OF SHOWERS ARE SEEN THROUGH THE
WEEKEND.

HIGH CLOUDS CONTINUE TO THIN OUT. THE COMPACT UPPER LEVEL LOW THAT
HAS BEEN GENERATING THE HIGH CLOUDS IS WEAKENING. THE WEAKENED
VERSION OF THE UPPER LOW WILL LINGER OVER THE REGION THROUGH THE
WEEK AND MAY PRODUCE ANOTHER BOUT OF THICK HIGH CLOUDS ON SATURDAY.

TAKING A LOOK AT THE EXTENDED FORECAST...THE CURRENT THINKING IS
FOR DECREASING TRADE WINDS AND MODEST WINDWARD RAINFALL. A NORTH
PACIFIC TROUGH WILL ERODE THE RIDGE TO OUR NORTH...LEADING TO A
DECREASE IN TRADE WINDS TO MODERATE STRENGTH. THE TROUGH WILL SEND A
REMNANT FRONTAL BAND SOUTHWARD DURING THE MIDDLE OF NEXT WEEK...BUT
ANY ENHANCED RAINFALL DOES NOT LOOK TO REACH THE ISLANDS BEFORE
WEDNESDAY.

&&

.AVIATION...
BREEZY AND GUSTY TRADE WINDS PERSISTING THROUGH 24 HOURS AND
BEYOND. AIRMET TANGO FOR MECHANICAL TURBULENCE TO THE LEE OF
MOUNTAINS SHOULD REMAIN NECESSARY THROUGH AT LEAST TOMORROW MORNING.

AIRMASS OVER THE STATE IS DRIER AND MORE STABLE TODAY THAN IT HAS
BEEN FOR SEVERAL DAYS BUT LOCALLY BRISK TRADE WINDS ARE STILL PILING
UP LOW VFR CLOUDS AGAINST WINDWARD EXPOSURES. MVFR CEILINGS IN
PASSING SHOWERS HAVE BECOME ISOLATED AND ARE EXPECTED TO REMAIN SO
THROUGH AT LEAST TOMORROW MORNING. AIRMET SIERRA FOR MTN OBSC HAS
BEEN CANCELLED.

&&

.MARINE...
WITH TRADE WINDS DECLINING A NOTCH...THE SMALL CRAFT ADVISORY /SCA/
HAS BEEN SCALED DOWN TO COVER THE TYPICALLY WINDY WATERS AROUND THE
BIG ISLAND AND MAUI AS WELL AS ALL CHANNELS. THE SCA HAS BEEN PUSHED
OUT THROUGH FRIDAY...SINCE FRESH TO STRONG TRADE WINDS ARE EXPECTED
TO HOLD THROUGH AT LEAST THE REMAINDER OF THE WORK WEEK. WE MAY
EVEN SEE A SLIGHT INCREASE ON THURSDAY. A SLOW DECREASING TREND WILL
TAKE PLACE DURING THE WEEKEND...WITH THE SCA POSSIBLY BEING DROPPED
COMPLETELY SUNDAY OR MONDAY.

ROUGH SURF JUST BELOW THE ADVISORY LEVEL IS EXPECTED THROUGH FRIDAY
ALONG EAST FACING SHORES. WINDWARD BUOYS HAVE BEEN HOLDING AROUND 8
FT 8 SECONDS TODAY WITH LITTLE VARIATION EXPECTED THROUGH THE WORK
WEEK. A MODERATE NORTHWEST SWELL WILL ARRIVE WEDNESDAY...PEAK
THURSDAY THEN GRADUALLY SUBSIDE INTO THE WEEKEND.

&&

.HFO WATCHES/WARNINGS/ADVISORIES...

SMALL CRAFT ADVISORY UNTIL 6 PM HST FRIDAY FOR KAUAI CHANNEL-
KAIWI CHANNEL-MAALAEA BAY-PAILOLO CHANNEL-ALENUIHAHA CHANNEL-BIG
ISLAND LEEWARD WATERS-BIG ISLAND SOUTHEAST WATERS.

&&

$$

DISCUSSION/MARINE...WROE
AVIATION...BEDAL




THE WEATHER PREDICTION CENTER

COLLEGE PARK, MD

HAWAII EXTENDED FORECAST DISCUSSION




HAWAII EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
752 AM EDT TUE APR 22 2014

VALID 00Z WED APR 23 2014 - 00Z WED APR 30 2014

EXPECT MODERATE TO BRISK TRADES THROUGH SAT AS HIGH PRESSURE
INITIALLY TO THE NE OF THE ISLANDS IS QUICKLY REPLACED BY ANOTHER
HIGH SETTLING TO THE N ALONG 30-35N LATITUDE.  THIS HIGH IS FCST
TO WEAKEN AROUND LATE SAT-SUN AS AN AMPLIFYING TROUGH ALOFT PUSHES
A COLD FRONT TOWARD THE REGION.  DURING SUN-TUE THERE IS SOME
SPREAD FOR THE AMPLITUDE OF THE TROUGH... WITH THE 00Z ECMWF MOST
AMPLIFIED AND 00Z GEFS MEAN THE FLATTEST.  AS A RESULT THE ECMWF
BRINGS THE FRONT FARTHEST SWD.  AT THIS TIME THE BEST INTERMEDIATE
SOLN ALOFT WOULD BE A COMPROMISE AMONG THE 00Z/06Z GFS AND
SLIGHTLY MORE AMPLIFIED 00Z ECMWF MEAN WITH A CORRESPONDING SFC
FRONT POSN A LITTLE SWD OF THE GFS.  GENERALLY WINDWARD-FOCUSED
RNFL SHOULD BE MOSTLY LGT-MDT AS PWATS REMAIN IN THE 1.00-1.25
INCH RANGE FOR MOST OF THE PERIOD... THOUGH LOCALIZED ENHANCEMENT
IS PSBL GIVEN VARYING DEGREES OF WEAKNESS ALOFT INTO THE WEEKEND.

RAUSCH





Last Updated: 752 AM EDT TUE APR 22 2014




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