000 WTPZ42 KNHC 020836 TCDEP2 TROPICAL STORM BLANCA DISCUSSION NUMBER 7 NWS NATIONAL HURRICANE CENTER MIAMI FL EP022015 400 AM CDT TUE JUN 02 2015 The cloud pattern of Blanca has become a little better organized overnight with increased banding and very deep convection over the center. However, there has been no recent microwave imagery to assess the structure of the inner core. Although the Dvorak T-numbers are a little higher, a recent ASCAT pass suggest that the maximum winds are still 40 to 45 kt. Therefore, the initial intensity remains 45 kt for this advisory. The shear that has been affecting the cyclone during the past day or so appears to have decreased with better anticyclonic outflow noted over Blanca. The tropical storm appears to be poised to intensify as a favorable environment characterized by low shear, warm water, and a moist atmosphere is expected during the next few days. The NHC forecast remains in good agreement with the SHIPS and FSU Superensemble guidance, which both predict rapid strengthening during the next day or two. Late in the forecast period, increasing shear and cooler SSTs should result in weakening. The ASCAT data suggest that Blanca has drifted westward overnight, however, little overall motion is forecast during the next couple of days while the cyclone remains in an area of weak steering flow. After 48 hours, a mid-level ridge is forecast to strengthen and shift eastward over northern Mexico. This should cause Blanca to move northwestward at a faster forward speed beginning Thursday. A northwestward to north-northwestward motion should continue on days 3 through 5 while Blanca moves around the southwestern periphery of the ridge. The model guidance is in good agreement on this scenario, but has shifted slightly westward this cycle. The updated NHC forecast has been nudged in that direction, and lies a little east of the model consensus. FORECAST POSITIONS AND MAX WINDS INIT 02/0900Z 13.3N 104.6W 45 KT 50 MPH 12H 02/1800Z 13.3N 104.7W 60 KT 70 MPH 24H 03/0600Z 13.1N 104.9W 75 KT 85 MPH 36H 03/1800Z 12.9N 104.9W 90 KT 105 MPH 48H 04/0600Z 12.9N 104.9W 105 KT 120 MPH 72H 05/0600Z 15.0N 106.5W 120 KT 140 MPH 96H 06/0600Z 17.9N 108.6W 100 KT 115 MPH 120H 07/0600Z 21.0N 110.0W 75 KT 85 MPH $$ Forecaster Brown