000 WTPZ41 KNHC 191457 TCDEP1 TROPICAL STORM RICK DISCUSSION NUMBER 5 NWS NATIONAL HURRICANE CENTER MIAMI FL EP212015 900 AM CST THU NOV 19 2015 The cloud pattern of the cyclone is better organized than this time yesterday. First-light visible imagery indicates that the low-level center is underneath a circular mass of deep convection, and there has been an increase in banding features and their associated curvature. The increase in organization could be a sign of some decrease of the southeasterly shear that has been affecting the cyclone. A Dvorak intensity estimate of T2.5 from TAFB and an UW-CIMSS ADT value of 2.9 is used to raise the initial intensity estimate to 35 kt. Some further decrease in southeasterly shear is likely through early Friday. With large-scale environmental conditions otherwise largely favorable, intensification is shown through about 24 to 36 hours. The window of opportunity for strengthening should be short- lived though, since west-southwesterly shear is forecast to increase by 48 hours when Rick moves north of the upper-level ridge axis. The shear should become prohibitively high by 72 hours ahead of a shortwave trough in the eastern Pacific subtropics being ejected eastward toward the cyclone. The result should be rapid weakening, and remnant low status is likely by 96 hours, if not sooner. Dissipation is now shown by 120 hours. The new NHC intensity forecast is slightly above the previous one, and shows and earlier peak, with remnant low status indicated sooner. The center has been difficult to locate but seems to be slightly farther east than previous estimates based on a couple of microwave passes and visible imagery. The best estimate of the initial motion is north or 360/06. Global models show mid-level ridging building to the north of the cyclone today, and the depression should be respond by moving more quickly toward the northwest and then west-northwest over the next day or two. Rick should reach the western periphery of this ridge in 3 to 4 days and begin to move more poleward, but will likely dissipate before responding to the trough in the subtropics moving toward it. The new track forecast is right of the previous one, primarily due to the more eastward initial position estimate. Only 3 tropical storms have formed later than this calendar date in the eastern North Pacific since reliable records began in the early 1970s. FORECAST POSITIONS AND MAX WINDS INIT 19/1500Z 14.7N 105.8W 35 KT 40 MPH 12H 20/0000Z 15.2N 106.5W 40 KT 45 MPH 24H 20/1200Z 16.2N 108.5W 50 KT 60 MPH 36H 21/0000Z 17.1N 110.6W 50 KT 60 MPH 48H 21/1200Z 17.7N 112.0W 45 KT 50 MPH 72H 22/1200Z 19.0N 113.4W 35 KT 40 MPH 96H 23/1200Z 20.9N 114.6W 20 KT 25 MPH...POST-TROP/REMNT LOW 120H 24/1200Z...DISSIPATED $$ Forecaster Kimberlain