Issued at 1100 AM AST Mon Oct 13 2025
000 WTNT42 KNHC 131453 TCDAT2 Tropical Storm Lorenzo Discussion Number 2 NWS National Hurricane Center Miami FL AL122025 1100 AM AST Mon Oct 13 2025 Lorenzo has maintained a large area of convection with cold cloud tops, although the latest GOES-19 1-minute visible satellite images suggest that the low-level center is near the southwestern edge of this convection, which makes sense due to the strong southwesterly wind shear over the cyclone. Overall, Lorenzo's structure hasn't changed much over the past 6 hours. However, a timely recent ASCAT pass shows a large area of 40-45 kt winds mainly in the northeast quadrant, so the initial intensity is increased to 45 kt, which is slightly above the latest objective current satellite intensity estimates from UW-CIMSS. The initial motion estimate is northwestward, or 310 degrees at 14 kt. Lorenzo is near the southwestern periphery of a mid-level high centered near the Cabo Verde Islands. Farther northwest, a mid- to upper-level trough is acting to erode the subtropical ridge. This trough is expected to fracture and shift to the southwest of the system, and Lorenzo should turn northward on Tuesday between this feature and the eroded mid-level ridge centered over the Cabo Verde Islands. Lorenzo is forecast to recurve northeastward on Wednesday as the cyclone comes under the influence of broad-scale mid-latitude westerly flow. If Lorenzo is still alive by Friday, it could approach a weakness in steering flow, with mid- to upper-level ridging possibly centered to the north or northeast of the cyclone, so the track forecast shows a slowdown with a turn to the east in 4-5 days. The track guidance is in good agreement through the 72 hour point, but spread increases significantly after that time. The new NHC track forecast is slightly west of the previous NHC prediction through hour 60, and lies close to the HFIP Corrected Consensus (HCCA) during that time period. At Day 5, the new NHC forecast is south of the previous prediction. Lorenzo continues to experience about 25 kt of southwesterly wind shear, although the shear is forecast to decrease significantly later today, and relatively light shear is anticipated from tonight through Thursday. Ordinarily, this would lead to strengthening given the sufficently warm 27-28 C ocean temperatures, but at the same time, environmental mid-level relatively humidity is also expected to decrease substantially as the storm interacts with the upper-level trough ahead of it. This trough could also still produce some residual mid-level shear undercutting the outflow layer. Most of the intensity guidance is not that enthusiastic about Lorenzo's prospects, but there are a couple of ECMWF ensemble members and a handful of Google DeepMind ensemble members that make Lorenzo a hurricane. The NHC intensity forecast is unchanged from the previous advisory other than the slightly stronger initial intensity, and is near the high end of the intensity guidance suite, showing little change in strength in the short-term, and then gradual intensification afterwards. The NHC intensity forecast is still generally higher than the HCCA, HAFS, and the intensity consensus. There is some possibility that the aforementioned dry air could cause Lorenzo to dissipate before the end of the 5-day period, as suggested by some of the global and hurricane regional models, but the NHC forecast maintains it as a tropical storm. FORECAST POSITIONS AND MAX WINDS INIT 13/1500Z 14.8N 41.2W 45 KT 50 MPH 12H 14/0000Z 15.6N 42.7W 45 KT 50 MPH 24H 14/1200Z 17.2N 44.1W 45 KT 50 MPH 36H 15/0000Z 19.2N 44.9W 45 KT 50 MPH 48H 15/1200Z 21.4N 44.9W 50 KT 60 MPH 60H 16/0000Z 23.9N 43.5W 55 KT 65 MPH 72H 16/1200Z 26.7N 41.2W 60 KT 70 MPH 96H 17/1200Z 31.4N 34.4W 55 KT 65 MPH 120H 18/1200Z 31.8N 29.8W 45 KT 50 MPH $$ Forecaster Hagen
