000 WTPZ41 KNHC 090244 TCDEP1 TROPICAL STORM FAUSTO DISCUSSION NUMBER 6 NWS NATIONAL HURRICANE CENTER MIAMI FL EP062014 800 PM PDT TUE JUL 08 2014 Visible satellite imagery indicates that the center of Fausto has pulled northwestward away from the main convective cloud mass and is now fully exposed in the middle of the larger scale cyclonic gyre. The initial intensity has been decreased to 35 kt based on satellite current intensity estimates of 35 kt and 39 kt from TAFB and UW-CIMSS ADT, respectively. The initial motion is 290/16 kt, which is a 12-hour average motion. A recent northwestward jog in the track is believed to be a temporary motion, and Fausto is expected to turn back toward the west-northwest fairly soon. A strong ridge to the north of the cyclone is expected to keep Fausto moving west-northwestward for the for the next 72 hours. After that, the cyclone is expected to weaken and become vertically shallow, being steered more westward by the brisk low-level trade wind flow. The official forecast track is a little to the right of and faster than the previous advisory, mainly due to the more northward initial position, and is similar to the consensus model TCVE. Fausto is experiencing light deep-layer vertical wind shear of less than 5 kt and the mid-level shear is only around 5 kt, so the sudden development of an exposed low-level circulation is perplexing. However, various water vapor products and microwave satellite imagery suggest that dry mid-level air has intruded into the inner core, disrupting the deep convection and allowing the low-level vortex to briefly decouple from the mid- and upper-level circulations. Further exacerbating these unfavorable conditions is a large disturbance located about 800 nmi to the northeast of the cyclone, which has been deflecting some of the southerly low-level inflow away from Fausto and into that system. The global models indicate that the shear will remain light for another 24 hours or so, and that Fausto and the aforementioned disturbance will begin to separate from each other in about 12 hours or so, which could allow for some slight re-strengthening. By 72 hours and beyond, however, northwesterly wind shear is forecast to increase to more than 30 kt, inducing significant weakening while the cyclone also moves over cooler water. The NHC intensity forecast is lower than the previous advisory forecast, and closely follows the intensity consensus models IVCN and ICON. FORECAST POSITIONS AND MAX WINDS INIT 09/0300Z 11.0N 126.5W 35 KT 40 MPH 12H 09/1200Z 11.7N 128.8W 35 KT 40 MPH 24H 10/0000Z 12.5N 131.7W 40 KT 45 MPH 36H 10/1200Z 13.4N 134.9W 40 KT 45 MPH 48H 11/0000Z 14.2N 137.6W 40 KT 45 MPH 72H 12/0000Z 16.0N 142.8W 30 KT 35 MPH 96H 13/0000Z 17.4N 146.5W 25 KT 30 MPH...POST-TROP/REMNT LOW 120H 14/0000Z 18.4N 150.0W 25 KT 30 MPH...POST-TROP/REMNT LOW $$ Forecaster Stewart