Tropical Storm Howard forms…
Tropical Storm Howard forms…
Tropical Storm Howard Discussion Number 6
NWS National Hurricane Center Miami FL EP092022
300 PM MDT Sun Aug 07 2022
Since this morning, convection has been attempting to build over the northern semicircle of the cyclone. While the low-level circulation remains partially exposed to the south, the coldest cloud tops below -70 C have rotated cyclonically in the up-shear direction, which could foreshadow an attempt of the mid-level center aligning with the low-level center in the future. Subjective and objective Dvorak intensity estimates this afternoon were a consensus T2.5/35 kt. Consequently, Tropical Depression Nine-E has been upgraded to Tropical Storm Howard with 35 kt winds this advisory.
The storm has continued a general motion to the northwest, estimated at 315/10 kt. The track philosophy has not changed much today, as Howard should continue to move northwestward into a relative weakness in the mid-level ridging. The track guidance this cycle has taken a noticeable shift to the northwest over the first 24-48 hours of the forecast, and the latest NHC track has also been shifted in that direction. Thereafter, Howard is likely to become vertically shallow, and increasingly steered by the low-level flow. The track forecast after 48 hours shows a bend westward in response to this transition, and follows closely with the consensus aids HCCA and TVCE.
The short-term intensity forecast is interesting. While Howard is clearly still feeling some effects of southwesterly vertical wind shear, the deepest convection has pivoted into the northern side of the storm. This could be the first signs that the upper-level trough to the west of Howard is starting to weaken and shift away from the storm. In addition, the raw model output grids of the GFS, ECMWF, and HWRF all suggest some sort of center reformation or relocation under the convection between 12-36 hours. This process may help to align the low and mid-level centers of the storm. This improved structure would also likely result in more intensification than previously shown, and the latest intensity forecast now takes Howard up to 50 kt in 36 hours. After that, the storm will be crossing a sharp sea surface temperature gradient and moving into a more stable environment, ultimately leading to steady weakening and its demise as a tropical cyclone by 96 hours. The latest NHC intensity forecast has a higher peak than before, but is still a tad under the latest HCCA guidance.
FORECAST POSITIONS AND MAX WINDS
INIT 07/2100Z 17.6N 110.7W 35 KT 40 MPH
12H 08/0600Z 19.0N 111.8W 40 KT 45 MPH
24H 08/1800Z 20.6N 113.3W 45 KT 50 MPH
36H 09/0600Z 21.8N 115.0W 50 KT 60 MPH
48H 09/1800Z 22.9N 116.8W 50 KT 60 MPH
60H 10/0600Z 23.8N 118.5W 40 KT 45 MPH
72H 10/1800Z 24.5N 120.1W 35 KT 40 MPH
96H 11/1800Z 25.0N 123.0W 30 KT 35 MPH…POST-TROP/REMNT LOW
120H 12/1800Z 24.5N 126.0W 25 KT 30 MPH…POST-TROP/REMNT LOW
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