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Tropical Storm HERNAN


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TROPICAL STORM HERNAN DISCUSSION NUMBER  22
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   EP092008
800 PM PDT MON AUG 11 2008

CONVECTION CONTINUES TO SLOWLY DECREASE NEAR THE CENTER OF THE
CYCLONE. IN ADDITION...MICROWAVE IMAGES SUGGEST THE LOW-LEVEL
CIRCULATION OF HERNAN APPEARS TO BE DETACHED SOMEWHAT TO THE
SOUTHEAST OF THE HIGHER-LEVEL CIRCULATION. IN ACCORDANCE WITH
SATELLITE ESTIMATES...THE INITIAL INTENSITY IS LOWERED TO 55 KT.
ALL SIGNS POINT TO A CONTINUED WEAKENING OF HERNAN...WITH COLD
WATER AND STABLE AIR IN ITS FUTURE. THE OFFICIAL FORECAST IS CLOSE
TO THE LGEM MODEL...WHICH HAS VERIFIED WELL IN THE PAST FOR EASTERN
PACIFIC SYSTEMS DISSIPATING OVER COOL WATERS. MOST OF THE MODEL
GUIDANCE SUGGESTS THIS SYSTEM WILL BECOME A REMNANT LOW IN ABOUT
THREE DAYS...OR SOONER.  

HERNAN APPEARS TO HAVE TURNED DUE WEST AT ABOUT 8 KT TONIGHT.
GUIDANCE IS IN GOOD AGREEMENT ON A WEST-SOUTHWESTWARD MOTION
TOMORROW AS STEERING CURRENTS BECOME DOMINATED BY STRONG LOW-LEVEL
RIDGING TO THE NORTH OF THE TROPICAL CYCLONE. THIS FORECAST
SCENARIO IS CONSISTENT WITH THE DYNAMICAL MODEL CONSENSUS AND THE
LATEST FORECAST IS JUST A LITTLE SOUTH OF THE PREVIOUS FORECAST.
HERNAN OR ITS REMNANT CIRCULATION IS EXPECTED TO CROSS INTO THE
CENTRAL PACIFIC BASIN ON THURSDAY.
 
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      12/0300Z 18.9N 131.7W    55 KT
 12HR VT     12/1200Z 18.7N 132.9W    45 KT
 24HR VT     13/0000Z 18.3N 134.5W    40 KT
 36HR VT     13/1200Z 17.8N 136.1W    35 KT
 48HR VT     14/0000Z 17.2N 137.6W    30 KT...DISSIPATING
 72HR VT     15/0000Z 16.0N 141.3W    25 KT...REMNANT LOW
 96HR VT     16/0000Z 15.5N 145.5W    25 KT...REMNANT LOW
120HR VT     17/0000Z 15.5N 149.5W    20 KT...REMNANT LOW
 
$$
FORECASTER BLAKE
 
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