000 WTPZ42 KNHC 220249 TCDEP2 TROPICAL STORM FRANK DISCUSSION NUMBER 2 NWS NATIONAL HURRICANE CENTER MIAMI FL EP072016 1000 PM CDT THU JUL 21 2016 Convention and microwave satellite imagery indicate that the convection associated with Frank has become better organized, with a strong burst occurring just south of the center. Based on the previous scatterometer data and the increase in organization, the initial intensity is increased to 45 kt. The best estimate of the current motion is 310/15, a little faster than earlier. Frank is located to the south of a large and strong mid-level anticyclone which is centered over the Southern Plains of the United States and has a ridge extending well westward into the eastern Pacific. The dynamical models forecast a slight weakness in the ridge over the northeastern Pacific during the next few days. The ECMWF shows a stronger weakness and thus forecasts Frank to move farther north, while the GFS keeps a stronger ridge and forecasts a more westward motion. Overall, the guidance envelope has shifted westward away from the coast of Mexico during the later part of the forecast period, and the official forecast follows suit. However, there is still enough uncertainty that interests in the southern portion of the Baja California peninsula should monitor the progress of Frank. Frank is expected to remain over warm water for the next 3 days or so. However, easterly shear could inhibit intensification, especially if the stronger upper-level winds forecast by the ECMWF verify. The new intensity forecast is similar to the previous forecast in showing strengthening through 72 hours, and like the previous forecast it lies near the upper end of the intensity guidance. Weakening is forecast after 72 hours due to decreasing sea surface temperatures along the forecast track and continued shear. FORECAST POSITIONS AND MAX WINDS INIT 22/0300Z 16.1N 105.2W 45 KT 50 MPH 12H 22/1200Z 17.0N 106.7W 50 KT 60 MPH 24H 23/0000Z 17.9N 108.2W 60 KT 70 MPH 36H 23/1200Z 18.6N 109.5W 65 KT 75 MPH 48H 24/0000Z 19.4N 110.9W 70 KT 80 MPH 72H 25/0000Z 21.0N 113.0W 75 KT 85 MPH 96H 26/0000Z 22.5N 115.0W 65 KT 75 MPH 120H 27/0000Z 23.5N 117.0W 55 KT 65 MPH $$ Forecaster Beven