000 WTPZ43 KNHC 032037 TCDEP3 TROPICAL STORM BLAS DISCUSSION NUMBER 4 NWS NATIONAL HURRICANE CENTER MIAMI FL EP032016 300 PM MDT SUN JUL 03 2016 Blas' cloud pattern has not changed appreciably in organization since the previous advisory. Visible and microwave satellite imagery suggests that the cyclone's low-level center is located at the northern tip of a long band whose convective tops have been slowly warming. This structure suggests that Blas' rate of intensification is not as fast as was suspected earlier, possibly due to some northeasterly shear and likely the cyclone's large size. The initial intensity is set to 55 kt based on the latest Dvorak intensity estimates of T3.5 from TAFB and SAB. The initial motion estimate is a steady 285/11. There has been no change to the track forecast philosophy since the previous advisory. Blas is forecast to move west-northwestward throughout the forecast period along the southern periphery of a deep-layer subtropical ridge extending westward from northern Mexico. The GFS and ECMWF solutions have come into much better agreement beyond day 3, and the overall spread in the guidance is low through day 5. The new NHC forecast track is shifted to the north some, and lies very near the multi-model consensus. There does not appear to be anything conspicuous on the large scale that would prevent Blas from intensifying into a major hurricane during the next few days, and a large one at that. The NHC intensity forecast through day 3 is near or just below the statistical guidance, which is unanimously calling for Blas to become an intense hurricane. By 96 hours, even though the shear is forecast to remain low, the cyclone should be moving over steadily cooler waters and entering a drier and more stable environment. This should promote a weakening trend that will likely become more rapid by the end of the forecast period. FORECAST POSITIONS AND MAX WINDS INIT 03/2100Z 12.2N 111.4W 55 KT 65 MPH 12H 04/0600Z 12.8N 113.0W 65 KT 75 MPH 24H 04/1800Z 13.4N 115.4W 75 KT 85 MPH 36H 05/0600Z 13.9N 117.7W 90 KT 105 MPH 48H 05/1800Z 14.3N 120.0W 100 KT 115 MPH 72H 06/1800Z 15.5N 124.3W 110 KT 125 MPH 96H 07/1800Z 16.8N 128.6W 90 KT 105 MPH 120H 08/1800Z 18.4N 132.3W 70 KT 80 MPH $$ Forecaster Kimberlain