500 WTPZ43 KNHC 082031 TCDEP3 Tropical Storm Kristy Discussion Number 8 NWS National Hurricane Center Miami FL EP132018 200 PM PDT Wed Aug 08 2018 Kristy's overall structure hasn't changed much over the past few hours, but cloud tops associated with the deepest convection have noticeably warmed. The intensity estimates from all agencies have also not changed, so the initial intensity has been held at 40 kt. Unfortunately, the various intensity models have not changed, either and the spread remains high. While the HWRF continues to show Kristy quickly strengthening to hurricane intensity, all of the statistical-dynamical guidance keeps the tropical storm very weak throughout the forecast period. The NHC forecast therefore continues to split the difference between these scenarios and shows slow strengthening for a couple of days while the cyclone remains in a low-shear environment. By days 4 and 5, Kristy is forecast to be moving over much cooler SSTs and through a more stable environment, which should cause it to weaken and become a remnant low. The track forecast is also still low confidence. Although Kristy is currently moving west-northwestward with an initial motion of 300/5 kt, the models are in good agreement that Kristy will turn northward overnight and tomorrow due to a weakness in the subtropical ridge created by Hurricane John. The uncertainty grows substantially beyond 24 h. The GFS continues to insist on a steering flow that will cause Kristy to become wrapped up in the larger circulation of John, while the UKMET and ECMWF show only a slow northward motion, followed by a turn back toward the west or northwest once the cyclone becomes a remnant low. The NHC forecast has been favoring the western solution, and I don't see an obvious reason to change that reasoning at this time. Therefore, little change has been made to the track forecast, which lies near a consensus of those two models, a little west of the multi-model consensus. FORECAST POSITIONS AND MAX WINDS INIT 08/2100Z 14.7N 129.6W 40 KT 45 MPH 12H 09/0600Z 15.3N 130.0W 40 KT 45 MPH 24H 09/1800Z 16.2N 130.3W 45 KT 50 MPH 36H 10/0600Z 17.2N 130.3W 50 KT 60 MPH 48H 10/1800Z 18.2N 130.0W 50 KT 60 MPH 72H 11/1800Z 20.2N 130.0W 45 KT 50 MPH 96H 12/1800Z 21.3N 130.7W 35 KT 40 MPH 120H 13/1800Z 22.0N 132.0W 25 KT 30 MPH...POST-TROP/REMNT LOW $$ Forecaster Zelinsky