Tropical Storm LANE
ZCZC MIATCDEP3 ALL TTAA00 KNHC DDHHMM TROPICAL STORM LANE DISCUSSION NUMBER 3 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL EP132006 200 AM PDT THU SEP 14 2006 SATELLITE IMAGERY INDICATES THAT THE CYCLONE CONTINUES TO BECOME BETTER ORGANIZED WITH INCREASING BANDING NOTED TO THE WEST. BASED ON THIS TREND AND DVORAK INTENSITY ESTIMATES OF 35 KT FROM TAFB AND UW CIMSS ADT...THE CYCLONE IS UPGRADED TO A 35 KT TROPICAL STORM. LANE APPEARS TO BE EXPERIENCING A LITTLE NORTHEASTERLY SHEAR AS EVIDENCED BY THE OVERALL CLOUD MASS FAVORED TO THE WEST OF THE CENTER. HOWEVER...MOST OF THE GLOBAL MODELS INDICATE THAT A LARGE UPPER-LEVEL ANTICYCLONE WILL FORM OVER LANE DURING THE NEXT DAY OR SO PRODUCING A LOW SHEAR ENVIRONMENT. THIS ENVIRONMENT COUPLED WITH A WARM UNDERLYING OCEAN SHOULD ALLOW FURTHER INTENSIFICATION. IN FACT...THE SHIPS MODEL SHOWS A 46% PROBABILITY OF RAPID INTENSIFICATION DURING THE NEXT 24 HOURS. THE OFFICIAL FORECAST IS SLIGHTLY BELOW THIS RATE GIVEN THE CURRENT SHEARED APPEARANCE IN SATELLITE IMAGERY. TOWARD THE END OF THE FORECAST...THE INTENSITY IS PROBLEMATIC. SHOULD LANE TRACK OVER OR WEST OF BAJA...COOLER WATERS AND LAND INTERACTION WOULD FAVOR WEAKENING. IF LANE TAKES A MORE EASTWARD MOTION...AS INDICATED BY THE GFDL AND UKMET MODELS...THE CYCLONE COULD POTENTIALLY BE OVER THE WARMER WATERS OF THE GULF OF CALIFORNIA. THE NEW FORECAST IS SIMILAR TO THE PREVIOUS ADVISORY. LANE CONTINUES TO MOVE TOWARD THE WEST-NORTHWEST...OR 300/9...AROUND THE SOUTHWESTERN PERIPHERY OF A SUBTROPICAL RIDGE OVER NORTHERN MEXICO. THIS GENERAL MOTION IS EXPECTED TO CONTINUE FOR THE NEXT COUPLE OF DAYS WITH LANE FORECAST TO PARALLEL THE SOUTHWESTERN COAST OF MEXICO. THEREAFTER...GLOBAL MODELS SHOW A MID-LATITUDE TROUGH AMPLIFYING SOUTHWARD OVER THE WESTERN UNITED STATES...PRODUCING A BREAK IN THE RIDGE AND ALLOWING LANE TO TURN INCREASINGLY NORTHWARD. THIS PATTERN HAS RESULTED IN A SIGNIFICANT EASTWARD SHIFT OF THE MODEL GUIDANCE REQUIRING A LARGER THAN NORMAL ADJUSTMENT TO THE OFFICIAL FORECAST. THE NEW FORECAST INDICATES AN INCREASED THREAT TO THE BAJA PENINSULA AND MAINLAND MEXICO. IT SHOULD BE NOTED THAT THE GFDL MODEL...WHICH PERFORMED VERY WELL DURING HURRICANE JOHN...IS THE EASTERNMOST DYNAMICAL MODEL AND IS SIGNIFICANTLY EAST OF THE OFFICIAL FORECAST. INDEED...GLOBAL MODELS OFTEN STRUGGLE IN SITUATIONS WHERE CYCLONES ARE NEAR THE COAST OF MEXICO...AND ADDITIONAL EASTWARD ADJUSTMENTS MAY BE REQUIRED IN SUBSEQUENT FORECASTS. BY DAYS 4 AND 5...THE TRACK BECOMES INCREASINGLY UNCERTAIN. IF LANE MAINTAINS VERTICAL DEPTH...IT COULD TURN TOWARD THE NORTHEAST AS IT ENCOUNTERS INCREASING WESTERLY FLOW. A WEAKER AND MORE SHALLOW CYCLONE WOULD TEND TO CONTINUE NORTHWARD. THE OFFICIAL FORECAST MAINTAINS A NORTHWARD MOTION...ALBEIT IT VERY SLOW GIVEN THE UNCERTAINTY. FORECAST POSITIONS AND MAX WINDS INITIAL 14/0900Z 16.9N 102.9W 35 KT 12HR VT 14/1800Z 17.3N 103.9W 45 KT 24HR VT 15/0600Z 18.1N 105.1W 55 KT 36HR VT 15/1800Z 19.0N 106.5W 65 KT 48HR VT 16/0600Z 20.0N 107.7W 70 KT 72HR VT 17/0600Z 22.0N 109.5W 75 KT 96HR VT 18/0600Z 24.0N 111.0W 70 KT...NEAR BAJA PENINSULA 120HR VT 19/0600Z 25.5N 111.5W 60 KT...INLAND $$ FORECASTER RHOME/KNABB NNNN