Tropical Storm NORBERT

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TROPICAL STORM NORBERT DISCUSSION NUMBER  10
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   EP152008
200 AM PDT MON OCT 06 2008
 
THE CLOUD PATTERN ASSOCIATED WITH NORBERT HAS CONTINUED TO 
GRADUALLY IMPROVE.  THE LATEST MICROWAVE IMAGERY AND AN 0121 UTC
QUIKSCAT PASS SUGGEST THAT THE CENTER OF NORBERT IS LOCATED A
LITTLE TO THE SOUTH AND EAST OF THE PREVIOUS ESTIMATES...BUT WELL
WITHIN THE AREA OF DEEP CONVECTION.  THE INITIAL INTENSITY REMAINS
55 KT...BASED ON DVORAK T3.5 OR 55 KT FROM BOTH TAFB AND SAB. 

NORBERT CONTINUES TO MOVE WESTWARD OR 270/6.  NORBERT IS FORECAST
TO MOVE ON A WEST TO WEST-NORTHWESTWARD MOTION TO THE SOUTH OF A
NARROW MID-LEVEL RIDGE DURING THE NEXT FEW DAYS.  THEREAFTER...A
TROUGH IS FORECAST TO DIG SOUTHWARD ALONG THE WEST COAST OF THE
UNITED STATES WHICH SHOULD ALLOW THE CYCLONE TO TURN NORTHWARD IN 
ABOUT 96 HOURS.  THE OVERALL TRACK GUIDANCE ENVELOPE HAS CHANGED
LITTLE...BUT SOME OF THE INDIVIDUAL MODELS HAVE BEEN SHOWING SOME
RUN TO RUN INCONSISTENCIES.  THE GFDL WHICH WAS ALONG THE EASTERN
EDGE OF THE GUIDANCE HAS MADE A SIGNIFICANT SHIFT WESTWARD BACK
TOWARD THE MIDDLE OF THE PACK.  THERE ALSO CONTINUES TO BE A LARGE
SPREAD IN THE GUIDANCE ON THE PREDICTED FORWARD SPEED OF NORBERT. 
THE ECMWF AND GFS ARE MUCH SLOWER THAN THE NOGAPS...UKMET...AND
HWRF WHICH ALL BRING THE CYCLONE INTO THE BAJA PENINSULA WITHIN 5
DAYS.  GIVEN THE LARGE SPREAD OF THE GUIDANCE...ESPECIALLY AT THE
LONG RANGE...THE NEW OFFICIAL FORECAST REMAINS NEAR THE MODEL
CONSENSUS AND THE PREVIOUS NHC TRACK.

CONDITIONS APPEAR FAVORABLE FOR GRADUAL STRENGTHENING DURING THE
NEXT FEW DAYS...AND NORBERT IS EXPECTED TO BECOME A HURRICANE.  THE
OFFICIAL FORECAST IS A LITTLE HIGHER THAN THE SHIPS GUIDANCE...BUT
IS LOWER THAN THE VERY AGGRESSIVE HWRF MODEL.  BY 96 HOURS...NORBERT
IS EXPECTED TO BE NEARING COOLER WATERS AND BEYOND THAT TIME...
SOUTHWESTERLY SHEAR IS FORECAST TO INCREASE.  THEREFORE...WEAKENING
IS PREDICTED AT DAYS 4-5...BUT THE OFFICIAL FORECAST DOES NOT SHOW
AS MUCH WEAKENING AS INDICATED BY THE SHIPS AND LGEM GUIDANCE.
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      06/0900Z 14.1N 103.9W    55 KT
 12HR VT     06/1800Z 14.3N 104.8W    65 KT
 24HR VT     07/0600Z 14.6N 105.9W    70 KT
 36HR VT     07/1800Z 15.1N 107.2W    75 KT
 48HR VT     08/0600Z 15.8N 108.5W    80 KT
 72HR VT     09/0600Z 17.7N 111.0W    80 KT
 96HR VT     10/0600Z 20.0N 112.5W    75 KT
120HR VT     11/0600Z 23.0N 112.5W    60 KT
 
$$
FORECASTER BROWN
 
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