Tropical Cyclone Discussion
Issued by NWS
Issued by NWS
846 WTNT45 KNHC 090250 TCDAT5 Tropical Storm Jerry Discussion Number 7 NWS National Hurricane Center Miami FL AL102025 1100 PM AST Wed Oct 08 2025 A very large and cold convective burst has formed near and to the east of Jerry this evening, with cloud top temperatures below -80 C and plenty of ongoing lightning near the overshooting tops. During this period, an Air Force Reserve reconnaissance mission has been sampling the storm, and found a peak 850 mb flight level wind of 66 kt on their northeast outbound leg of the storm. In addition, there was a dropsonde launched in the inner max wind band near the center, which had a 500 m mean boundary layer wind of 71 kt and a surface wind gust of 55 kt. Using a 0.8 reduction factor to the layer mean wind supports the current intensity of 55 kt, which also matched the T3.5/55 kt Dvorak estimate provided by TAFB. Jerry continues to move quickly to the west-northwest, although the convective burst may have slowed down its motion a tad, estimated at 290/18 kt. The forecast track reasoning remains the same this evening, with a subtropical ridge well-established to the northeast of the storm, and Jerry will likely be steered around this feature, turning to the northwest in 24 hours, and then north by 48 hours. On the forecast track, this takes Jerry about 80-100 n mi to the northeast of the northern Leeward islands by late tomorrow. There remain a few hurricane-regional model outliers to the west (HMON, HAFS-A), but these models appear to be struggling to depict the cyclone within their inner-nests. The overall track guidance envelope has remained pretty steady state this evening, and the NHC forecast track is very close to the prior advisory, blending the reliable HCCA and GDMI aids. By early next week, the track guidance has made a more notable shift south as Jerry recurves around the subtropical ridge, and the track forecast was nudged further south and east in the 120 h period. While this track puts Jerry safely southeast of Bermuda, it`s a good idea to continue monitoring future forecasts since model scenarios can change, and NHC track forecasts at day 4 have an average error of 130 n mi. Despite the large convective burst, Jerry still remains under moderate to strong northwesterly shear, currently estimated at around 25 kt per GFS and ECMWF-based SHIPS. However, Jerry has been putting up a good fight thus far and its wind field has intensified despite the continued unfavorable conditions, likely because of other more favorable factors like sea-surface temperatures and an unstable environment. The intensity guidance this evening presents a challenge. The 18 UTC GFS, and the hurricane-regional models based on the GFS, all show very little change in strength and even dissipate Jerry in the 72-96 h time frame. However, a glance at the short-term model forecast shows the GFS is struggling to correctly depict the convective structure of Jerry. To make matters more confusing, the last several ECMWF runs now show a much stronger Jerry in the 48-96 h time frame, with the 18 UTC run showing a strengthening hurricane with pressure below 960 mb. Ultimately, I`m going to split the difference between these two extreme solutions, showing Jerry slowly intensifying over the next 24-36 h, then showing a little more intensification after as the shear decreases to 15-20 kt in 36 h after the tropical cyclone passes north of the Leeward Islands. Needless to say this is a low confidence intensity forecast, and overall the NHC forecast is on the high side of the guidance envelope. KEY MESSAGES: 1. Jerry could bring tropical storm conditions to portions of the northern Leeward Islands late Thursday and Thursday night. 2. Heavy rainfall will impact portions of the Leeward Islands, British Virgin Islands, and U.S. Virgin Islands from Thursday into Saturday morning, which could result in flash flooding, particularly in areas of steep terrain. FORECAST POSITIONS AND MAX WINDS INIT 09/0300Z 15.2N 56.1W 55 KT 65 MPH 12H 09/1200Z 16.4N 58.3W 60 KT 70 MPH 24H 10/0000Z 18.0N 60.6W 60 KT 70 MPH 36H 10/1200Z 20.1N 62.2W 65 KT 75 MPH 48H 11/0000Z 22.5N 62.8W 70 KT 80 MPH 60H 11/1200Z 25.0N 62.8W 75 KT 85 MPH 72H 12/0000Z 27.4N 62.3W 75 KT 85 MPH 96H 13/0000Z 31.2N 60.5W 75 KT 85 MPH 120H 14/0000Z 32.3N 56.0W 75 KT 85 MPH $$ Forecaster Papin