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140 WTPZ45 KNHC 152039 TCDEP5 TROPICAL DEPRESSION TWENTY-E DISCUSSION NUMBER 1 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL EP202009 200 PM PDT THU OCT 15 2009 CONVENTIONAL SATELLITE IMAGERY...DATA FROM THE ASCAT SCATTEROMETER...AND SHIP REPORTS INDICATE THAT THE LOW PRESSURE AREA CENTERED SOUTH OF MEXICO HAS ACQUIRED SUFFICIENT ORGANIZED CONVECTION AND CIRCULATION TO BE DESIGNATED A TROPICAL DEPRESSION. THE ASCAT DATA SHOWED MAXIMUM WINDS NEAR 30 KT ABOUT 60 N MI NORTH-NORTHEAST OF THE CENTER...WHICH IS IN GOOD AGREEMENT WITH SATELLITE INTENSITY ESTIMATES FROM TAFB AND SAB. THE CIRRUS OUTFLOW IS CURRENTLY GOOD IN ALL DIRECTIONS. THE INITIAL MOTION IS A SOMEWHAT UNCERTAIN 305/11. THE DEPRESSION IS ON THE SOUTH SIDE OF A LOW/MID-LEVEL RIDGE EXTENDING FROM MEXICO WESTWARD OVER THE PACIFIC. THE LARGE-SCALE MODELS FORECAST THIS FEATURE TO PERSIST FOR THE NEXT 48-72 HR...AND THIS SHOULD STEER THE DEPRESSION WEST-NORTHWESTWARD AT A SLIGHTLY SLOWER FORWARD SPEED. AFTER THAT TIME...THE RIDGE IS FORECAST TO WEAKEN AS A MID/UPPER-LEVEL TROUGH DEVELOPS OVER THE WESTERN UNITED STATES. THE TRACK GUIDANCE DIVERGES DURING THIS TIME. THE HWRF AND GFDL... WHICH ARE ON THE RIGHT SIDE OF THE GUIDANCE ENVELOPE...TURN THE CYCLONE TO THE NORTH OR NORTHEAST BY 120 HR...WITH THE GFDL FORECASTING THE CENTER TO BE NEAR SOUTHERN BAJA CALIFORNIA. THE NOGAPS...CANADIAN...AND UKMET ARE ON THE OTHER SIDE OF THE ENVELOPE...AND SHOW A SLOW WEST-NORTHWESTWARD MOTION AFTER 72 HR. THE GFS AND ECMWF ARE IN BETWEEN THESE EXTREMES...WITH 120 HR POSITIONS JUST SOUTH OR SOUTHWEST OF SOCORRO ISLAND. THE FORECAST TRACK COMPROMISES BETWEEN THESE EXTREMES...WITH THE TRACK IN BEST AGREEMENT WITH THE TVCN CONSENSUS MODEL FOR THE FIRST 72 HR AND WITH THE GFS/ECMWF THEREAFTER. THE DEPRESSION IS EMBEDDED IN A LIGHT VERTICAL WIND SHEAR ENVIRONMENT OVER VERY WARM WATER...AND THE LARGE-SCALE MODELS FORECAST THIS TO CONTINUE THROUGH AT LEAST 72 HR. ALL GUIDANCE IS FORECASTING SIGNIFICANT AND RAPID STRENGTHENING DURING THE NEXT 72-96 HR...WITH THE HWRF FORECASTING THE CENTRAL PRESSURE TO FALL BELOW 900 MB. THE RAPID INTENSIFICATION INDEX OF THE SHIPS MODEL INDICATES A 60 PERCENT CHANCE OF 30 KT OR MORE INTENSIFICATION DURING THE NEXT 24 HR. THE INTENSITY FORECAST THUS CALLS FOR FAST STRENGTHENING...WITH THE DEPRESSION BECOMING A TROPICAL STORM BY 12 HR...A HURRICANE IN ABOUT 36 HR...AND A MAJOR HURRICANE IN ABOUT 72 HR. THE INTENSITY FORECAST IS SIMILAR TO THE SHIPS AND INTENSITY CONSENSUS MODELS. THERE IS A CHANCE THAT THE CYCLONE COULD STRENGTHEN FASTER THAN CURRENTLY FORECAST. THE INITIAL RADII OF 12 FT SEAS ARE BASED ON TWO SHIP REPORTS 130 AND 170 N MI FROM THE CENTER IN THE EASTERN SEMICIRCLE. FORECAST POSITIONS AND MAX WINDS INITIAL 15/2100Z 12.1N 97.0W 30 KT 12HR VT 16/0600Z 12.6N 98.2W 40 KT 24HR VT 16/1800Z 13.0N 99.7W 55 KT 36HR VT 17/0600Z 13.4N 101.3W 65 KT 48HR VT 17/1800Z 13.9N 103.3W 80 KT 72HR VT 18/1800Z 15.0N 108.0W 100 KT 96HR VT 19/1800Z 17.0N 111.5W 110 KT 120HR VT 20/1800Z 19.0N 112.5W 115 KT $$ FORECASTER BEVENReturn to the Tropical Systems Page for RICK Back to main Tropical Weather page
This page was last modified on: Thu, Jul 23 2020 - 2003 UTC Send comments to: Ryan Lyman |
