Subject: Central Pacific: Satellite Interpretation Message

From: LDM Weather <[email-masked]>
Date: Sat, 18 Dec 2010 06:31:34 -0600

567 
ATHW40 PHFO 181231
SIMHI 

HAWAIIAN ISLANDS SATELLITE INTERPRETATION MESSAGE
NWS CENTRAL PACIFIC HURRICANE CENTER HONOLULU HI
1230 UTC SAT DEC 18 2010

BASED ON DATA THROUGH 1200 UTC DECEMBER 18 2010

THE WESTERN EDGE OF A WEAK WEST NORTHWEST TO EAST SOUTHEAST ORIENTED 
SURFACE RIDGE WAS LOCATED ABOUT 315 MILES NORTH OF HONOLULU. THE 
PRESSURE GRADIENT SOUTH OF THIS NEARLY STATIONARY FEATURE CONTINUED 
TO MAINTAIN RELATIVELY LIGHT SOUTHEASTERLY FLOW ACROSS THE STATE 
EARLY THIS MORNING. THERE WERE MAINLY SCATTERED LOW CLOUDS OVER THE 
HAWAIIAN COASTAL WATERS EAST OF KAUAI. THERE WERE ISOLATED LIGHT 
SHOWERS EMBEDDED WITHIN SOME OF THE LOW CLOUDS SOUTHEAST OF THE BIG 
ISLAND. THE INDIVIDUAL LOW CLOUD ELEMENTS WERE GENERALLY MOVING 
NORTHWESTWARD AT ABOUT 10 MPH OVER THE COASTAL WATERS FROM OAHU TO 
THE BIG ISLAND. THE HIGHEST TOPS OF THE LOW CLOUDS OVER THE OCEAN IN 
THE SAME AREA WERE ESTIMATED TO BE 5 TO 6 THOUSAND FEET.

HOWEVER...BROKEN LAYERED CLOUDS AND ISOLATED SHOWERS WERE OVER THE 
WESTERN HAWAIIAN COASTAL WATERS JUST WEST OF KAUAI AND NIIHAU. SOME 
OF THIS PRECIPITATION APPEARED TO BE LOCALLY HEAVY...WITH A FEW OF 
THE ECHO TOPS ESTIMATED TO BE NEAR 20 THOUSAND FEET ACCORDING TO 
RADAR. THE INDIVIDUAL RAIN PRODUCING ELEMENTS WERE MOVING NORTHWARD 
AT 15 TO 20 MPH ACCORDING TO RADAR REFLECTIVITY DATA. IN ADDITION TO 
THE LOW CLOUDS OVER THE HAWAIIAN COASTAL WATERS...SCATTERED TO 
BROKEN CIRRUS CLOUDS WERE ALSO MOVING RAPIDLY EASTWARD HIGH ABOVE 
SKIES OVER THE ISLANDS. THE LAYERED CLOUDS AND PRECIPITATION JUST 
WEST OF KAUAI...AS WELL AS THE HIGH THIN CLOUDS MOVING ACROSS THE 
ALOHA STATE...WERE ALONG THE EXTREME EASTERN EDGE OF A LARGE COMPLEX 
WEATHER SYSTEM THAT EXTENDED ALMOST TO THE INTERNATIONAL DATE LINE. 
THE HIGH CLOUDS WERE MAKING TO DIFFICULT TO IDENTIFY LOW CLOUDS OVER 
THE ISLANDS ISLANDS USING INFRARED SATELLITE IMAGERY TONIGHT.

ACCORDING TO LOOPS OF WATER VAPOR IMAGERY AND SATELLITE DERIVED 
UPPER LEVEL WINDS...AN UPPER TROPOSPHERIC LOW WAS CENTERED JUST EAST 
OF THE DATE LINE NEAR 22N 178.5W. THIS FEATURE HAS BEEN MOVING 
SOUTHWARD AT ALMOST 20 MPH DURING THE PAST 6 HOURS. EAST OF THIS 
UPPER LEVEL LOW...THE CORE OF A SUBTROPICAL JET EXTENDED FROM NEAR 
15N 176W TO 22N 173W TO 30N 172W. A BROAD AREA OF OVERCAST LAYERED 
CLOUDS WITH RAIN AND EMBEDDED THUNDERSTORMS ASSOCIATED WITH THE 
DIFFLUENCE ALOFT DUE TO THIS JET WAS SLIGHTLY LESS THAN 1000 MILES 
EAST OF A LINE FROM 13N 176W TO 24N 174W TO 30N 174.5W. A SURFACE 
LOW...WHICH WAS A REFLECTION OF THE UPPER LEVEL LOW ALOFT...WAS ALSO 
EVIDENT IN SATELLITE IMAGERY NEAR 23.8N 178.6W...OR ABOUT 310 MILES 
SOUTH SOUTHWEST OF MIDWAY ATOLL. SHOWERS AND NUMEROUS THUNDERSTORMS 
WERE WITHIN 140 MILES OF THIS LOW...WHICH HAS CHARACTERISTICS OF A 
SUBTROPICAL SYSTEM BASED ON EARLIER SCATTEROMETER PASSES AND ITS 
INFRARED SATELLITE SIGNATURE. THE HIGHEST TOPS OF THE THUNDERSTORMS 
WITHIN THE CORE OF THIS SYSTEM WERE ESTIMATED TO BE ABOUT 40 
THOUSAND FEET.

ELSEWHERE...THE AXIS OF AN UPPER TROPOSPHERIC TROUGH EXTENDED FROM 
NEAR 20N 145W TO 13.5N 147.5W TO 08.5N 147W...OR ABOUT 580 MILES 
SOUTHEAST OF HILO. THIS TROUGH ALOFT HAS BEEN PROPAGATING SLOWLY 
TOWARD THE EAST NORTHEAST DURING THE PAST 6 HOURS. ISOLATED 
THUNDERSTORMS ASSOCIATED WITH THIS FEATURE...WHICH HAVE DECREASED IN 
COVERAGE AND INTENSITY DURING THE PAST 6 HOURS...WERE IN THE AREA 
FROM 12N TO 15.5N BETWEEN 142.5W AND 147.5W.

$$

HOUSTON

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