Tropical Storm Gonzalo Forecast Discussion
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303 WTNT42 KNHC 250246 TCDAT2 Tropical Storm Gonzalo Discussion Number 1 NWS National Hurricane Center Miami FL AL072026 200 AM CVT Fri Sep 25 2026 Satellite imagery indicates that the area of low pressure (Invest AL90) has developed a closed, albeit slightly elongated, low-level circulation this morning along with organized deep convection. This convection is currently displaced mainly over the eastern and southern semicircles of the circulation due to moderate westerly vertical wind shear. Recent scatterometer data show maximum winds near 40 kt in the northeastern quadrant, and TAFB provided a subjective Dvorak satellite intensity estimate of T2.5/35 kt. Based on these data, advisories are being initiated on Tropical Storm Gonzalo with an initial intensity of 40 kt. A Tropical Storm Warning has been issued for all the Cabo Verde Islands. The initial motion is somewhat uncertain given the recent formation of the center, but the best estimate is 330/7 kt. Gonzalo is expected to move north-northwestward during the next couple of days, steered by the flow of a deep mid-level trough over the eastern Atlantic. As this trough lifts northeastward later in the forecast period, the cyclone will be left behind in a very weak steering environment, causing it to drift slowly over the eastern Atlantic. On the forecast track, the center will pass near or over portions of the Cabo Verde Islands today and tonight. Track guidance is in fairly good agreement in the short term, though cross- and along-track differences emerge beyond day 2. The official NHC track forecast lies near the HCCA corrected consensus and the TVCN simple consensus aids. Gonzalo is currently located within a marginally conducive environment that could allow for some slight strengthening, characterized by sea surface temperatures near 27-28C and mid-level relative humidity values around 60 percent. In about 24 hours, vertical wind shear is forecast to increase to moderate-to-strong levels. This increase in shear, combined with cooling SSTs and a progressively drier mid-level environment, will cause a gradual weakening trend. The NHC intensity forecast lies near the HCCA corrected consensus aid. Global model simulated infrared satellite imagery depicts Gonzalo losing organized deep convection in about 3 days, and the forecast shows the system becoming a post-tropical remnant low at that time, and remaining a remnant low through the remainder of the forecast period. Key Messages: 1. Tropical storm conditions are expected to spread across portions of the Cabo Verde Islands, where a Tropical Storm Warning is in effect, later today and will continue through tonight. 2. Heavy rains from Gonzalo could affect the eastern islands of Cabo Verde and the western coast of Africa between Guinea-Bissau to Senegal today through Saturday. Areas of flash flooding will be possible along the western coast of Africa with some isolated flash flood concerns for the eastern islands of Cabo Verde. FORECAST POSITIONS AND MAX WINDS INIT 25/0300Z 13.2N 22.1W 40 KT 45 MPH 12H 25/1200Z 14.2N 22.6W 45 KT 50 MPH 24H 26/0000Z 15.6N 23.2W 45 KT 50 MPH 36H 26/1200Z 17.2N 23.5W 40 KT 45 MPH 48H 27/0000Z 18.7N 23.9W 35 KT 40 MPH 60H 27/1200Z 19.8N 24.2W 30 KT 35 MPH 72H 28/0000Z 20.2N 24.4W 25 KT 30 MPH...POST-TROP/REMNT LOW 96H 29/0000Z 20.9N 24.9W 20 KT 25 MPH...POST-TROP/REMNT LOW 120H 30/0000Z 21.7N 26.4W 20 KT 25 MPH...POST-TROP/REMNT LOW $$ Forecaster Kelly