000 WTPZ42 KNHC 020235 TCDEP2 TROPICAL STORM BLANCA DISCUSSION NUMBER 6 NWS NATIONAL HURRICANE CENTER MIAMI FL EP022015 1000 PM CDT MON JUN 01 2015 Blanca is gradually intensifying. Satellite imagery shows the cyclone maintaining a small CDO dominated by very cold-topped deep convection, with a vigorous primary band over the southeastern portion of the circulation. Microwave satellite data, however, indicate that Blanca's developing inner core currently lacks much organization. Regardless, anticyclonic flow over Blanca is also expanding and becoming better established, indicative of a continued decrease in shear. A blend of Dvorak intensity estimates is used to set the initial intensity to 45 kt. Blanca has been meandering southward, but the overall motion is essentially stationary. The cyclone should remain trapped in a col area during the next 36 hours, but there should be just enough northerly or north-northwesterly flow to nudge the center of Blanca on a general southerly course. By 72 hours, the synoptic steering over the eastern Pacific should change as an unusually deep longwave trough settles into southern California and weak mid-level ridging near Baja California shifts eastward and strengthens. This pattern should cause Blanca to accelerate on a heading between northwest and north-northwest beginning on Thursday. Only small adjustments were made to the NHC track forecast during the first 36-48 hours, but the track has been shifted to the right of the previous one between 72-120 hours, which is close to the multi-model consensus (TVCE). Northwesterly shear affecting the cyclone is forecast to decrease considerably within 24 hours and remain low for a couple of days after that, while thermodynamic parameters in the near-storm environment should be exceptionally conducive for rapid intensification. An eastward-traveling upper-level shortwave trough moving through Mexico in 48-72 hours could also enhance Blanca's outflow, increasing the likelihood of a significant deepening during this time. Late in the forecast period, east-southeasterly shear and cooler waters should result in weakening, especially by day 5. The NHC intensity forecast is increased above the previous one and is closest to the FSU Superensemble and SHIPS model output, and well above the weaker regional model solutions. FORECAST POSITIONS AND MAX WINDS INIT 02/0300Z 13.2N 104.0W 45 KT 50 MPH 12H 02/1200Z 13.0N 104.2W 55 KT 65 MPH 24H 03/0000Z 12.9N 104.4W 75 KT 85 MPH 36H 03/1200Z 12.7N 104.5W 90 KT 105 MPH 48H 04/0000Z 12.7N 104.3W 105 KT 120 MPH 72H 05/0000Z 14.5N 105.3W 120 KT 140 MPH 96H 06/0000Z 16.9N 107.7W 105 KT 120 MPH 120H 07/0000Z 20.1N 108.8W 85 KT 100 MPH $$ Forecaster Kimberlain