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Tropical Storm Kristy Forecast Discussion Number 7
2018-08-08 16:33:41| National Hurricane Center (East Pacific)
Issued at 800 AM PDT Wed Aug 08 2018 359 WTPZ43 KNHC 081433 TCDEP3 Tropical Storm Kristy Discussion Number 7 NWS National Hurricane Center Miami FL EP132018 800 AM PDT Wed Aug 08 2018 Kristy has continues to have the structure of a strongly sheared tropical cyclone. The low-level center has been difficult to identify overnight, but recent microwave data indicates that it is displaced to the northwest of the primary convective mass. The initial intensity has been held at 40 kt based on a blend of Dvorak Final-T numbers from TAFB and SAB. Although the low-level center has been somewhat difficult to track, it appears that Kristy has begun to turn west-northwestward, and the initial motion estimate is 290/7 kt. Little change has been made to the official track forecast, but confidence remains very low. A break in the subtropical ridge created by Hurricane John should allow Kristy to continue turning, resulting in a northward motion by Thursday. Beyond that time, the model spread remains high, fueled by a combination of uncertainty as to how much John and Kristy will directly interact, and how much Kristy will respond to an upper-level trough to the northwest. The GFS is a notable outlier on the east side of the guidance envelope, and is the only model showing Kristy wrapping around the circulation of John. For now, the NHC forecast continues to downplay this possibility, and is a little to the west of the multi-model consensus. The intensity guidance spread is also high, ranging from the HWRF which makes Kristy a hurricane, to the SHIPS and LGEM which forecast only gradual weakening. Since the shear is forecast to decrease over the next 12 to 24 hours, and Kristy will be moving away from the cold wake of Hector and over warmer waters, at least some strengthening seems likely. By the second half of the forecast period, the cyclone will be passing over much colder SSTs and through a drier environment, which should cause the cyclone to steadily weaken and become a remnant low. The NHC forecast is now close to the model consensus IVCN, which is higher this cycle. FORECAST POSITIONS AND MAX WINDS INIT 08/1500Z 14.4N 129.3W 40 KT 45 MPH 12H 09/0000Z 15.0N 130.0W 40 KT 45 MPH 24H 09/1200Z 15.9N 130.5W 45 KT 50 MPH 36H 10/0000Z 16.8N 130.6W 45 KT 50 MPH 48H 10/1200Z 17.7N 130.4W 50 KT 60 MPH 72H 11/1200Z 19.8N 130.2W 45 KT 50 MPH 96H 12/1200Z 21.5N 131.5W 35 KT 40 MPH 120H 13/1200Z 22.0N 133.0W 25 KT 30 MPH...POST-TROP/REMNT LOW $$ Forecaster Zelinsky
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