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Tropical Storm Elida Forecast Discussion Number 7
2020-08-10 16:36:30| National Hurricane Center (East Pacific)
Issued at 900 AM MDT Mon Aug 10 2020 000 WTPZ44 KNHC 101436 TCDEP4 Tropical Storm Elida Discussion Number 7 NWS National Hurricane Center Miami FL EP092020 900 AM MDT Mon Aug 10 2020 Elida is very close to reaching hurricane strength. A 1218 UTC SSMIS microwave pass revealed a nearly enclosed eyewall that was somewhat eroded on the west side, possibly due to a bit of north-northwesterly shear (as shown by the SHIPS diagnostics). Subjective Dvorak estimates from TAFB and SAB are T3.5/55 kt, while the objective guidance from UW-CIMSS is about 5-10 kt higher. Because of the gradually improving structure in microwave imagery, the initial intensity is set at 60 kt, which is a blend of the intensity estimates. Located along the southern periphery of a mid-level ridge which extends from the south-central U.S. southwestward into the Pacific, Elida is moving west-northwestward at 300/13 kt. Confidence in the track forecast remains high since this ridge will be the main driving force for the next 2-3 days, keeping Elida on a west-northwestward but gradually slowing trajectory. In about 3 days, a weaker Elida will turn westward and slow down even further due to lighter low-level steering winds. The spread in the guidance does increase beyond 60 hours, particularly with the GFS showing a significant poleward motion, but this unlikely scenario appears to be due to the model tracker deviating from the path of the surface circulation. The new NHC track forecast is nudged only slightly north of the previous forecast, mainly due to a continuation of Elida's recent trajectory. This new forecast is a blend of the previous forecast and the NOAA-HCCA and TVDG consensus approaches. The SHIPS model suggests that whatever shear is still affecting Elida should die down within the next 12 hours, and the storm has about 24 hours left over waters warmer than 26 degrees Celsius. These conditions should allow for continued strengthening over the next day or so, with rapid intensification still a possibility. For that reason, the NHC intensity forecast is just above nearly all of the guidance at 24 hours. After 24 hours, gradual weakening should commence as Elida moves over cooler waters, and the rate of weakening is likely to accelerate by day 3 once southwesterly shear increases. Elida is expected to become a remnant low by day 4 and dissipate by day 5, in accordance with the solutions shown by the global models. FORECAST POSITIONS AND MAX WINDS INIT 10/1500Z 18.9N 109.8W 60 KT 70 MPH 12H 11/0000Z 19.7N 111.9W 70 KT 80 MPH 24H 11/1200Z 20.5N 114.5W 80 KT 90 MPH 36H 12/0000Z 21.3N 117.0W 75 KT 85 MPH 48H 12/1200Z 22.0N 119.3W 65 KT 75 MPH 60H 13/0000Z 22.5N 121.3W 50 KT 60 MPH 72H 13/1200Z 22.7N 122.8W 40 KT 45 MPH 96H 14/1200Z 22.5N 125.5W 25 KT 30 MPH...POST-TROP/REMNT LOW 120H 15/1200Z...DISSIPATED $$ Forecaster Berg
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