ZCZC MIATCDEP5 ALL TTAA00 KNHC DDHHMM TROPICAL STORM PATRICIA DISCUSSION NUMBER 3 NWS NATIONAL HURRICANE CENTER MIAMI FL EP202015 1000 PM CDT TUE OCT 20 2015 Although cloud tops have warmed since the previous advisory, the overall convective cloud pattern has become a little better organized. Dropsondes released from a NASA WB-57 aircraft conducting research in Patricia earlier this afternoon for the Office of Naval Research's Tropical Cyclone Intensity (TCI) experiment was helpful in locating the low-level center, and also confirmed the development of a weak mid-level eye-like feature noted in recent passive microwave images. The initial intensity has been increased to 35 kt based on a satellite intensity estimates of T2.5/35 kt from TAFB and T2.9/43 kt from UW-CIMMS ADT, making the cyclone the 16th named storm of the 2015 eastern North Pacific hurricane season. This intensity is also supported by dropsonde data in the southeastern quadrant of the cyclone between 2000-2200Z, which indicated surface winds of 34-36 kt and also a fairly deep layer of 37-39 kt winds from 1000-925 mb. Winds west of the center were 30 kt, suggesting that the Gulf of Tehuantepec gap wind gale event may be subsiding. The initial motion estimate is 255/04 kt. There is no significant change to the previous forecast track or reasoning. Patricia is expected to move west-southwestward to westward for the next 12 hours or so as the aforementioned gap wind event forces the cyclone a little southward. After that time, Patricia is forecast to turn west-northwestward on Wednesday and northwestward on Thursday as the cyclone rounds the southwestern periphery of a deep-layer ridge that extends from the central Gulf of Mexico southwestward into central Mexico. Although there is some spread in the NHC track guidance, the models are in fairly good agreement that Patricia should turn north-northwestward to northward by 72 hours, making landfall in southwestern Mexico. The new forecast track is similar to the previous track and lies close to the consensus models TVCE and GFEX. The large-scale environment of vertical shear less than 5 kt, very high mid-level humidity values in excess of 80 percent, and SSTs greater than 30C support at least steady strengthening until landfall occurs. The possibility of rapid intensification (RI) exists once a distinct eye feature develops, which could develop in 36 hours or so. The intensity forecast is similar to the previous advisory in calling for Patricia to become a hurricane before making landfall in Mexico, and closely follows the LGEM intensity model. However, if RI should occur, then Patricia will likely be stronger at landfall than the current forecast is indicating. After landfall, the cyclone should quickly weaken and dissipate over the mountains of Mexico. A tropical storm or hurricane watch may be required by Wednesday morning for portions of southwestern Mexico. FORECAST POSITIONS AND MAX WINDS INIT 21/0300Z 13.1N 95.3W 35 KT 40 MPH 12H 21/1200Z 13.0N 96.5W 40 KT 45 MPH 24H 22/0000Z 13.3N 98.3W 50 KT 60 MPH 36H 22/1200Z 14.2N 100.3W 60 KT 70 MPH 48H 23/0000Z 15.5N 102.0W 75 KT 85 MPH 72H 24/0000Z 18.8N 103.7W 85 KT 100 MPH...INLAND NEAR COAST 96H 25/0000Z 22.6N 105.1W 40 KT 45 MPH...INLAND 120H 26/0000Z...DISSIPATED $$ Forecaster Stewart NNNN