ZCZC MIATCDEP5 ALL TTAA00 KNHC DDHHMM TROPICAL STORM NEWTON DISCUSSION NUMBER 2 NWS NATIONAL HURRICANE CENTER MIAMI FL EP152016 1000 PM CDT SUN SEP 04 2016 A pair of ASCAT passes late this afternoon indicated that the depression was producing 30-35 kt winds on its southern side. Since the last advisory, the circulation and convective pattern have continued to improve, and both subjective and objective Dvorak estimates have increased. Based on all these data, the depression is upgraded to Tropical Storm Newton with maximum winds of 35 kt. There might be multiple low-level swirls rotating around a common center, but the best estimate of the center yields an initial motion of 340/7 kt. Newton is located to the south of a mid-tropospheric ridge which extends from Texas southwestward over the Pacific. However, an amplifying trough near California is expected to shunt the ridge eastward within the next 24 hours, which will help to accelerate Newton toward the northwest or north-northwest during the next couple of days. There is very little spread among the track guidance, but most of the models (with the exception of the EMCWF) are now a little faster than the previous NHC forecast. The new NHC forecast is therefore a little faster, bringing the center of Newton very close to the extreme southern Baja California peninsula in about 36 hours. After that, Newton is forecast to turn northward, moving over the Baja California peninsula, the Gulf of California, and into northwestern mainland Mexico by day 3. Newton is over very deep, warm water at the moment, and SSTs are expected to be between 28-30C until the cyclone reaches the Baja California peninsula. In addition, vertical shear is expected to remain low for the next couple of days. Therefore, Newton is expected to strengthen before it reaches land, with rapid intensification not out of the question. The Rapid Intensification Index currently shows a 1-in-4 chance of a 30-kt increase in winds during the next 24 hours. Most of the hurricane models, both dynamical and statistical, are only showing modest strengthening, but the global model fields indicate that Newton could be near hurricane intensity when it is near the Baja California peninsula. Therefore, the NHC intensity forecast now brings Newton to just below hurricane intensity in 36 hours, which is at the high end of the guidance. Weakening should occur after 36 hours due to interaction with land and increasing vertical shear. Although the official forecast does not explicitly show Newton becoming a hurricane, it will be close enough to hurricane strength that the Government of Mexico has issued a hurricane warning for the extreme southern Baja California peninsula. Additional tropical storm watches and warnings have been issued since Newton's wind field is expected to expand. FORECAST POSITIONS AND MAX WINDS INIT 05/0300Z 17.0N 105.7W 35 KT 40 MPH 12H 05/1200Z 18.4N 106.7W 40 KT 45 MPH 24H 06/0000Z 20.2N 108.2W 50 KT 60 MPH 36H 06/1200Z 22.3N 109.6W 60 KT 70 MPH 48H 07/0000Z 24.7N 110.8W 55 KT 65 MPH...OVER BAJA PENINSULA 72H 08/0000Z 29.9N 111.3W 35 KT 40 MPH...INLAND 96H 09/0000Z 34.5N 109.5W 20 KT 25 MPH...POST-TROP/REMNT LOW $$ Forecaster Berg NNNN