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Tropical Storm NICOLE Forecast Discussion Number 22
2016-10-09 17:03:15| National Hurricane Center (Atlantic)
Issued at 1100 AM AST SUN OCT 09 2016 000 WTNT45 KNHC 091503 TCDAT5 TROPICAL STORM NICOLE DISCUSSION NUMBER 22 NWS NATIONAL HURRICANE CENTER MIAMI FL AL152016 1100 AM AST SUN OCT 09 2016 Overnight microwave data indicated that Nicole had formed a well-defined low- to mid-level eye, embedded within a significant convective burst. Since then, the shear has caused the new convective growth to diminish and pushed the coldest cloud tops south of the low-level center. Satellite classifications are T3.0 and T3.5 from SAB and TAFB, respectively. A blend of these is used to set the initial intensity estimate to 50 kt. Nicole appears to have drifted southeastward during the last several hours, but is now essentially stationary. The blocking ridge north of Nicole has begun to shift eastward, which should cause the cyclone to begin a slow motion, generally toward the north. Variations in the orientation and strength of this ridge in the GFS and ECMWF solutions result in either a north-northeastward or north-northwestward motion, respectively, during the next couple of days, and these differences could have implications on Nicole's track longer term. A turn toward the northeast is expected late in the period when Nicole reaches the mid-latitude westerly flow. The split in the track guidance over the forecast period is notable this cycle, with the ECMWF and all but a few of its 0000 UTC ensemble members even or left of the previous forecast track. All of the other track guidance is to the east, including the GFS which is the rightmost of the members in this camp. The new forecast track is very near the previous one in deference to the ECMWF and its ensemble output even though the model consensus aids are to the east through 96 hours. The strong northerly shear over Nicole has marginally decreased since yesterday, but is forecast to remain at about the same magnitude for another 24 hours. The shear should then gradually diminish until about day 3, and Nicole is likely to find itself in the lowest-shear environment it has seen in several days. Since the cyclone will be over anomalously warm waters at that time, in a moist environment and under a somewhat diffluent flow aloft, intensification seems likely. The intensity forecast is increased over the previous one and is slightly above the multi-model consensus. It should be noted that the global models show significant deepening of Nicole starting around this time, potentially much more than what is indicated in this forecast. Southwesterly shear should greatly increase by day 4, which could curb any additional intensification after that time unless the cyclone's intensification is being driven by baroclinic forcing. FORECAST POSITIONS AND MAX WINDS INIT 09/1500Z 24.0N 65.4W 50 KT 60 MPH 12H 10/0000Z 24.4N 65.3W 55 KT 65 MPH 24H 10/1200Z 25.2N 65.3W 55 KT 65 MPH 36H 11/0000Z 26.1N 65.3W 55 KT 65 MPH 48H 11/1200Z 27.0N 65.6W 60 KT 70 MPH 72H 12/1200Z 28.6N 65.9W 65 KT 75 MPH 96H 13/1200Z 31.8N 64.2W 70 KT 80 MPH 120H 14/1200Z 34.9N 59.4W 70 KT 80 MPH $$ Forecaster Kimberlain
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