ZCZC MIATCDEP5 ALL TTAA00 KNHC DDHHMM TROPICAL STORM NEWTON DISCUSSION NUMBER 4 NWS NATIONAL HURRICANE CENTER MIAMI FL EP152016 900 AM MDT MON SEP 05 2016 Newton's cloud pattern is characterized by large mass of very cold-topped convection with the center located underneath this formative central dense overcast on the north side. A ship earlier reported 50 kt, and although this ship had somewhat of a high bias, the 12Z sounding from Manzanillo reported an 850 mb wind of 65 kt. A typical wind reduction over the water would suggest about 50 kt at the surface, and since the sounding supports the ship observation, the initial intensity is set to 50 kt. The center location of Newton has been difficult to determine, and hence the initial motion is an uncertain 330/11. Newton is currently being steered northwestward on the southwest side of a mid-level ridge over the United States lower Mississippi Valley. The cyclone should be drawn north-northwestward and then northward in 36 to 48 hours between this feature and a trough of low pressure gradually lifting out over the western United States. The official NHC track forecast is somewhat faster and slightly to the left of the previous one and near the multi-model consensus. It lies on the western side of the guidance, but with only the ECMWF and UKMET models to left. Newton is expected to remain in a very moist environment with generally light northeasterly shear during the next 24 hours. These factors, along with the cyclone's passage over sea surface temperatures above 29 deg C, should allow for steady intensification until the center reaches the coast. The only obvious obstacle to strengthening is Newton's broad structure, but indications are that the cyclone may be in the process of consolidating. It should be noted that the SHIPS RI index indicates a 60-70�hance of an intensity increase of around 25 kt during the next 24 hours. The NHC intensity forecast now calls for Newton to become a hurricane prior to landfall, which is little above the multi-model consensus. Weakening is likely when Newton moves across the Baja California peninsula, but little change in strength is expected as the southwesterly shear begins to increase over the Gulf of California in 36 to 48 hours. Newton is expected to be a large hurricane at landfall, and hazards are likely to affect a large portion of Baja California and northwestern Mexico. In addition, moisture associated with the remnants of Newton could cause heavy rains and localized flash flooding over parts of Arizona and New Mexico. Based on the new intensity and track forecasts, the government of Mexico has made a variety of changes to the watches and warnings. FORECAST POSITIONS AND MAX WINDS INIT 05/1500Z 19.1N 107.0W 50 KT 60 MPH 12H 06/0000Z 20.6N 108.4W 60 KT 70 MPH 24H 06/1200Z 22.8N 110.0W 70 KT 80 MPH 36H 07/0000Z 25.3N 111.3W 60 KT 70 MPH 48H 07/1200Z 28.1N 111.6W 50 KT 60 MPH...INLAND 72H 08/1200Z 33.5N 110.6W 25 KT 30 MPH...POST-TROP/REMNT LOW 96H 09/1200Z...DISSIPATED $$ Forecaster Kimberlain NNNN