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Tropical Storm Hilary Forecast Discussion Number 29
2017-07-28 16:38:51| National Hurricane Center (East Pacific)
Issued at 800 AM PDT Fri Jul 28 2017 000 WTPZ44 KNHC 281438 TCDEP4 Tropical Storm Hilary Discussion Number 29 NWS National Hurricane Center Miami FL EP092017 800 AM PDT Fri Jul 28 2017 Cloud tops near the center of Hilary continue to warm this morning, and a consensus of objective and subjective Dvorak intensity estimates suggests a decreased initial intensity of 55 kt. An AMSR pass at 0913 UTC showed a band of deep convection spiraling into the center. There is also a pronounced dry slot, indicative of the drier environment that the cyclone is moving into. Hilary is crossing the 26 C SST isotherm this morning, so the window for any reintensification is closing quickly, despite the insistence of the HWRF and GFS which both show a hurricane in 24 hours. Instead, the official forecast continues to follow the statistical models, which depict steady weakening until Hilary becomes a remnant low. The intensity forecast is a little lower than indicated in the previous advisory based on the lower initial intensity, but no significant changes have been made. The low-level center of the tropical storm was briefly visible this morning, and the initial motion is a fairly confident 305/7. There has been a significant shift in the guidance toward the north for this advisory, especially the GFS and the GFS-based hurricane models. The 06Z GFS in particular has shifted nearly 500 nm to the northeast at day 5 and no longer shows any significant interaction between Irwin and Hilary. The 00Z ECMWF also shifted a little north, but not nearly to the same extent. Interaction between the two cyclones, and the eventual absorption of Irwin by Hilary, is still expected for now, as shown by the UKMET and ECMWF. Based on the changes in the guidance, the official forecast has been shifted north, but still lies well south of the multi-model consensus aids. It does, however, fall near the middle of the ECMWF and GFS ensemble tracks. FORECAST POSITIONS AND MAX WINDS INIT 28/1500Z 19.2N 118.4W 55 KT 65 MPH 12H 29/0000Z 19.9N 119.5W 50 KT 60 MPH 24H 29/1200Z 20.9N 121.3W 45 KT 50 MPH 36H 30/0000Z 21.8N 123.2W 40 KT 45 MPH 48H 30/1200Z 22.8N 125.4W 35 KT 40 MPH 72H 31/1200Z 24.0N 129.4W 25 KT 30 MPH 96H 01/1200Z 24.8N 132.6W 20 KT 25 MPH...POST-TROP/REMNT LOW 120H 02/1200Z 26.5N 135.0W 20 KT 25 MPH...POST-TROP/REMNT LOW $$ Forecaster Zelinsky
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