000 WTPZ41 KNHC 012043 TCDEP1 TROPICAL STORM VANCE DISCUSSION NUMBER 11 NWS NATIONAL HURRICANE CENTER MIAMI FL EP212014 200 PM PDT SAT NOV 01 2014 Vance appears to be gradually organizing in satellite imagery. The central convection has increased a bit over the past few hours, and convective banding has also increased in coverage. However, satellite intensity estimates remain unchanged, and the initial intensity remains 40 kt. The increase in convective coverage is consistent with a gradual moistening of the near-storm environment as seen in the SHIPS model analyses, and conditions appear conducive for gradual strengthening during the next 48 hours. The NHC intensity forecast is similar to the previous one, and shows Vance reaching hurricane status in about 2 days. After that time, the shear increases dramatically, which should result in quick weakening to remnant low status by day 4. The NHC prediction is close to the Decay-SHIPS model and a little above the intensity consensus through the period. The initial motion estimate is 290/11, as Vance is feeling the effects of a strengthening mid-level ridge to the north. Vance should move generally west-northwestward through 24 hours and then turn northward by 48 hours as it moves between the ridge and an amplifying mid/upper-level trough digging southward over the southwestern United States and Baja California. Late in the period, a weakening Vance is expected to turn north-northeastward as the cyclone decouples in the strong shear, leaving a remnant low drifting erratically by the end of the forecast period. The guidance has trended faster in the short term this cycle, and generally shows a broader recurvature through 48 hours. The NHC forecast has been trended in that direction, but lies a little east of the multi-model consensus at 36 and 48 hours. After that time, the spread in the guidance increases. The ECMWF and UKMET models both show Vance interacting to some degree with a disturbance moving northward around the eastern side of the tropical cyclone. In particular, the ECMWF shows Vance weakening and then merging with the other system, resulting in a track far to the south of the rest of the models. The GFS remains farther north and east, but shows a westward turn by day 5. The NHC forecast late in the period has been slowed down and shows the remnant low meandering between Cabo San Lucas and Cabo Corrientes at days 4 and 5. However, this forecast is east of the multi-model consensus out of respect for continuity, and confidence in the details of the track forecast late in the period is quite low. FORECAST POSITIONS AND MAX WINDS INIT 01/2100Z 10.1N 104.4W 40 KT 45 MPH 12H 02/0600Z 10.8N 106.2W 45 KT 50 MPH 24H 02/1800Z 12.0N 108.8W 55 KT 65 MPH 36H 03/0600Z 13.5N 110.5W 60 KT 70 MPH 48H 03/1800Z 15.2N 111.0W 65 KT 75 MPH 72H 04/1800Z 18.7N 109.7W 45 KT 50 MPH 96H 05/1800Z 21.5N 108.0W 25 KT 30 MPH...POST-TROP/REMNT LOW 120H 06/1800Z 22.0N 108.0W 20 KT 25 MPH...POST-TROP/REMNT LOW $$ Forecaster Brennan