000 WTNT45 KNHC 200838 TCDAT5 Hurricane Jerry Discussion Number 12 NWS National Hurricane Center Miami FL AL102019 500 AM AST Fri Sep 20 2019 Jerry appears to have stopped strengthening for now. The last reports from the Air Force Hurricane Hunters indicated that the minimum pressure had risen slightly, and the satellite appearance has become a little more ragged during the past several hours. Radar images sent from the aircraft showed a well-defined inner core, but there are no hints of an eye in geostationary satellite images. The initial intensity is held at 90 kt based on the earlier aircraft data. Both the Air Force and NOAA Hurricane Hunters will be investigating Jerry later today, and that data should provide a better assessment of its intensity and structure. Jerry continues to move west-northwestward at a relatively quick pace of 14 kt. This motion is expected to continue for about another 24 hours as the cyclone is steered by a subtropical ridge to its northeast. The ridge is expected to weaken and slide eastward late this weekend in response to an eastward-moving trough over the north Atlantic. This change in the steering pattern should cause Jerry to slow down and gradually turn to the northwest and then the north late this weekend and early next week. A faster north- northeastward motion is anticipated toward the end of the forecast period as another trough approaches the system. The models remain in very good agreement on the hurricane passing well to the north of the northern Leeward Island and Puerto Rico late today and Saturday and possibly moving near Bermuda in a little more than 4 days. The only notable change this cycle is a slower northward motion from days 3 to 5 to be in better agreement with the latest models. The intensity forecast is a bit more challenging. The global models show a relatively favorable upper-level wind pattern over Jerry during the next couple of days, but there is also a significant amount of dry air around the cyclone. Although the shear could increase early next week, some of the models show Jerry deepening, likely due to baroclinic effects due to the nearby trough. There is a very large spread in the intensity guidance ranging from SHIPS and LGEM showing little change in strength to pronounced weakening shown by HMON during the forecast period. The NHC intensity forecast is between those extremes and lies a little above the consensus aids. Key Messages: 1. Although the core of Jerry is expected to move north of the northern Leeward Islands, heavy rainfall and flash floods are possible there today. FORECAST POSITIONS AND MAX WINDS INIT 20/0900Z 18.4N 58.7W 90 KT 105 MPH 12H 20/1800Z 19.1N 60.8W 85 KT 100 MPH 24H 21/0600Z 20.4N 63.3W 80 KT 90 MPH 36H 21/1800Z 21.8N 65.4W 75 KT 85 MPH 48H 22/0600Z 23.2N 67.1W 70 KT 80 MPH 72H 23/0600Z 26.1N 68.4W 65 KT 75 MPH 96H 24/0600Z 29.4N 66.8W 65 KT 75 MPH 120H 25/0600Z 34.6N 63.0W 65 KT 75 MPH $$ Forecaster Cangialosi