Satellite Interpretation Message
Issued by NWS

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000
ATHW40 PHFO 281230
SIMHI

HAWAIIAN ISLANDS SATELLITE INTERPRETATION MESSAGE
NWS CENTRAL PACIFIC HURRICANE CENTER HONOLULU HI
1230 UTC WED JAN 28 2015

BASED ON DATA THROUGH 1200 UTC JANUARY 28 2015

AS WAS THE CASE AT THE END OF THE DAY TUESDAY...REGIONAL SATELLITE
IMAGES CENTERED OVER THE MAIN HAWAIIAN ISLANDS CONTINUE TO SHOW A
STEADY STREAM OF BROKEN TO OVERCAST LOW CLOUDS MOVING TOWARD THE
ISLANDS FROM THE EAST. HOWEVER...LOW CLOUD MOTIONS NEAR AND WEST OF
KAUAI HAVE DIMINISHED TO THE POINT THAT THEY ARE NEARLY STATIONARY.
WHILE MOST OF THE INCOMING CLOUDS ARE STACKING UP ALONG WINDWARD
SLOPES AND COASTS OF THE ISLANDS...MANY LEEWARD AREAS OF THE ISLANDS
HAVE CONSIDERABLE OVERHEAD CLOUDINESS AS WELL...INCLUDING LEEWARD
LOWER SLOPES OF THE BIG ISLAND.

FROM OAHU TO THE BIG ISLAND...THE PREVAILING SKY CONDITION IS
CLOUDY...ESPECIALLY OVER WINDWARD COASTS...SLOPES AND ADJACENT
WATERS...WHERE THE STABLE LOW CLOUD FIELD IS NEARLY OVERCAST. FROM
OAHU TO KAUAI...LOW CLOUD COVERAGE DIMINISHES TO SCATTERED...WITH
PATCHES OF BROKEN LOW CLOUDS. WHILE LOW CLOUDS NEAR AND JUST EAST OF
THE BIG ISLAND ARE MOVING DUE WEST...NEAR THE ISLANDS THE FLOW IS
VEERING AND THE LOW CLOUDS ARE GENERALLY MOVING TOWARD THE
WEST-NORTHWEST...AT SPEEDS BETWEEN 15 AND 20 MPH. AS NOTED ABOVE
THOUGH...LOW CLOUD MOTIONS DIMINISH FROM EAST TO WEST ACROSS THE
AREA...TO THE POINT OF BECOMING NEARLY STATIONARY NEAR AND NORTHWEST
OF KAUAI.

LARGER SCALE IMAGES SHOW THE VEERING FLOW NEAR THE ISLANDS IS LIKELY
DUE TO THE PRESENCE OF A 200 MILE WIDE...NORTHEAST TO SOUTHWEST
ORIENTED...BAND OF BROKEN TO OVERCAST LOW AND MIDDLE CLOUDS CENTERED
ABOUT 550 MILES NORTHWEST OF KAUAI. THIS BAND...WHICH HAS BECOME
INCREASINGLY DIFFUSE OVER THE PAST 6 TO 8 HOURS...APPEARS TO MARK A
SURFACE FRONT...ALTHOUGH IT/S FORWARD MOTION TOWARD THE ISLANDS IS
VERY SLOW. THE LEADING EDGE OF THIS BAND EXTENDS SOUTHWESTWARD FROM
NORTH OF 30N THROUGH 30N158W TO 26N164W TO 20N180. THE PRESENCE OF
THIS BAND APPEARS TO HAVE LED TO A SOUTHWARD SUPPRESSION OF A
SURFACE RIDGE THAT EXTENDS SOUTHWESTWARD FROM A HIGH CENTERED ABOUT
1000 MILES NORTHEAST OF THE ISLANDS...WITH LOW CLOUD MOTIONS USED TO
HELP OUTLINE THE POSITION OF THE HIGH. ALSO NOTED IS THAT THE
OVERCAST STABLE LOW CLOUD FIELD NEAR THE ISLANDS EXTENDS ABOUT 500
MILES TO THE EAST OF THE ISLANDS...TO NEAR 146W...WITH LOW CLOUD
COVER DIMINISHING SLIGHTLY BETWEEN 146W AND 140W.

WATER VAPOR IMAGERY HELPS TO HIGHLIGHT A BROAD RIDGE ALOFT THAT
PREVAILS OVER THE ENTIRE TROPICAL CENTRAL NORTH PACIFIC...LEADING TO
LARGE SCALE SINKING MOTION...AND VERY DRY MID AND UPPER LEVELS
ACROSS THE REGION. WITH THE RIDGE PREVAILING...THE ENTIRE BASIN IS
DOMINATED BY SHALLOW LOW CLOUDS...WITH THUNDERSTORMS NOTICEABLY
ABSENT.

$$

BIRCHARD




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