000 WTPZ45 KNHC 080834 TCDEP5 HURRICANE NORBERT DISCUSSION NUMBER 18 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL EP152008 200 AM PDT WED OCT 08 2008 NORBERT HAS DEVELOPED A DISTINCT EYE SURROUNDED BY A RING OF VERY DEEP CONVECTION. THE UPPER-LEVEL OUTFLOW IS OUTSTANDING IN ALL QUADRANTS. T-NUMBERS HAVE INCREASED TO 5.5 ON THE DVORAK SCALES AND OBJECTIVE NUMBERS ARE A LITTLE BIT HIGHER. THE INITIAL INTENSITY IS SET CONSERVATIVELY AT 100 KT. THIS MAKES NORBERT A CATEGORY THREE HURRICANE ON THE SAFFIR-SIMPSON HURRICANE SCALE...THE SECOND MAJOR HURRICANE OF THE 2008 EASTERN NORTH PACIFIC HURRICANE SEASON. GIVEN THE UPPER-LEVEL WIND PATTERN AND THE WARM SSTS...NORBERT COULD REACH CATEGORY FOUR STATUS AS INDICATED IN THE OFFICIAL FORECAST. BEYOND 48 HOURS THE SHEAR IS FORECAST TO INCREASE RESULTING IN WEAKENING. NEVERTHELESS...NORBERT COULD APPROACH BAJA CALIFORNIA AS A CATEGORY TWO OR THREE HURRICANE. THE HURRICANE IS MOVING TOWARD THE WEST-NORTHWEST OR 295 DEGREES AT 9 KNOTS AROUND A STRONG RIDGE OVER THE SOUTHWESTERN UNITED STATES. IN A DAY OR SO...THE HURRICANE WILL REACH THE SOUTHWEST SIDE OF THE RIDGE AND SHOULD BEGIN TO TURN TO THE NORTH AND NORTH-NORTHEAST AS A BROAD MID LATITUDE TROUGH DEVELOPS OVER THE WESTERN UNITED STATES AND ADJACENT PACIFIC. MOST OF THE TRACK GUIDANCE FAVORS THIS SOLUTION BRINGING THE HURRICANE NEAR OR OVER BAJA CALIFORNIA IN ABOUT 72 HOURS. THE LARGEST DIFFERENCE IS BEYOND 72 HOURS WHEN BOTH THE GFS AND THE ECMWF EITHER DISSIPATE THE CYCLONE OR KEEP IT NEARLY STATIONARY VERY CLOSE TO BAJA CALIFORNIA. THE REST OF THE RELIABLE GUIDANCE BRINGS NORBERT ACROSS BAJA CALIFORNIA AND THEN TOWARD MAINLAND MEXICO AS A WEAKENING TROPICAL CYCLONE...AND SO DOES THE OFFICIAL FORECAST. HOWEVER...ONE CANNOT RULE OUT THE SOLUTION PROVIDED BY THE GFS AND THE ECMWF. WHILE IT IS STILL PREMATURE TO SAY WHAT KIND OF IMPACT NORBERT MAY HAVE ON BAJA CALIFORNIA...INTERESTS IN THE AREA...ESPECIALLY THE SOUTHERN PENINSULA...SHOULD MONITOR THE PROGRESS OF NORBERT. FORECAST POSITIONS AND MAX WINDS INITIAL 08/0900Z 16.1N 110.0W 100 KT 12HR VT 08/1800Z 16.7N 111.1W 110 KT 24HR VT 09/0600Z 17.5N 112.3W 115 KT 36HR VT 09/1800Z 18.5N 113.0W 115 KT 48HR VT 10/0600Z 20.0N 113.5W 100 KT 72HR VT 11/0600Z 24.0N 112.5W 95 KT 96HR VT 12/0600Z 27.5N 110.0W 40 KT...INLAND 120HR VT 13/0600Z 31.5N 107.5W 20 KT...INLAND $$ FORECASTER AVILA