Issued at 200 AM PDT Sun Sep 20 2026
000 WTPZ41 KNHC 200848 TCDEP1 Tropical Storm Odalys Discussion Number 1 NWS National Hurricane Center Miami FL EP162026 200 AM PDT Sun Sep 20 2026 Satellite imagery indicates that the convective organization of Odalys has improved over the past several hours. Deep convection continues to develop within a band wrapping around the western and southern semicircles, with a recent burst of convection expanding over or near the circulation center. The latest subjective Dvorak intensity estimate from TAFB is T2.5/35 kt. Given these data and the improved satellite presentation, advisories are being initiated on newly formed Tropical Storm Odalys, with an initial intensity of 35 kt. The initial motion is estimated to be northwestward, or 305/7 kt. This general motion is expected to continue during the next day or two as a low- to mid-level subtropical ridge remains positioned to the north. Thereafter, Odalys is forecast to slow considerably and turn sharply eastward by Tuesday, then east-northeastward through the latter part of the week in response to a developing weakness in the ridge as an upper-level trough deepens over the western United States. Although the track guidance remains in decent agreement through the first half of the week, increasing cross-track spread develops thereafter. This appears to be due, at least in part, to differences in how the models handle the evolution of the upper-level trough over the western United States and the potential influence of another developing tropical cyclone tracking west-northwestward offshore of southwestern Mexico. These factors lead to lower confidence in the track forecast during the latter portion of the forecast period. The NHC track forecast closely follows the HCCA and GDMI aids through around day 4, then reflects more of a blend of the two thereafter as the spread increases. Environmental conditions appear favorable for gradual strengthening during the next couple of days, with warm sea surface temperatures and plenty of deep moisture expected along the forecast track. However, modest north-northeasterly vertical wind shear may temper the rate of intensification during the next 24 h. Thereafter, the rate of strengthening could increase as the shear relaxes and Odalys remains in a favorable environment. The NHC forecast has the system becoming a hurricane by Monday, with some additional strengthening possible through Tuesday. Thereafter, progressively drier mid-level air, along with increasing vertical wind shear anticipated later in the forecast period, should induce a steady weakening trend. There is additional uncertainty in the intensity forecast due to the potential influence of another tropical cyclone evolving well to the east, which could affect its intensity depending on the eventual tracks and proximity of the two systems late in the week. The NHC intensity forecast lies near the middle to upper end of the guidance envelope through much of the period. FORECAST POSITIONS AND MAX WINDS INIT 20/0900Z 11.4N 124.5W 35 KT 40 MPH 12H 20/1800Z 12.0N 125.6W 45 KT 50 MPH 24H 21/0600Z 13.3N 127.1W 55 KT 65 MPH 36H 21/1800Z 14.4N 128.3W 65 KT 75 MPH 48H 22/0600Z 15.0N 128.9W 70 KT 80 MPH 60H 22/1800Z 15.2N 128.7W 70 KT 80 MPH 72H 23/0600Z 15.3N 128.0W 65 KT 75 MPH 96H 24/0600Z 15.6N 126.5W 65 KT 75 MPH 120H 25/0600Z 16.7N 124.8W 65 KT 75 MPH $$ Forecaster Gibbs
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