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#875675 (Received by flhurricane at: 5:01 AM 23.Sep.2016) TCDAT3 TROPICAL STORM LISA DISCUSSION NUMBER 15 NWS NATIONAL HURRICANE CENTER MIAMI FL AL132016 500 AM AST FRI SEP 23 2016 The center of Lisa has become fully exposed due to strong shear, like so many Atlantic tropical cyclones in 2016. Some convection remains, although well away from the center, in the northern semicircle. The initial wind speed is reduced to 35 kt, which is on the high side of the latest Dvorak estimates. Very strong shear should cause further weakening, along with marginal SSTS and increasingly dry air aloft. Deep convection will likely be struggling in that environment within 24 hours, and the new forecast has Lisa becoming a remnant low in 36 hours. Most of the global models now show Lisa decaying to a trough in 3 to 4 days before it gets absorbed by a cold front, but either way it should be a weak system by then. Lisa continues moving northwestward at about 8 kt. A track toward the west-northwest or northwest is expected for the next couple of days while the system moves around the subtropical ridge. Afterward the post-tropical cyclone should turn northward as it gets caught up in southerly flow ahead of Karl. The guidance has shifted westward on this cycle, possibly due to a weaker Lisa being steered more by the low-level subtropical ridge. Thus, the official forecast is moved westward as well, near or just west of the model consensus. FORECAST POSITIONS AND MAX WINDS INIT 23/0900Z 21.8N 35.7W 35 KT 40 MPH 12H 23/1800Z 22.7N 36.8W 30 KT 35 MPH 24H 24/0600Z 23.6N 38.3W 30 KT 35 MPH 36H 24/1800Z 24.6N 40.1W 25 KT 30 MPH...POST-TROP/REMNT LOW 48H 25/0600Z 26.1N 41.7W 25 KT 30 MPH...POST-TROP/REMNT LOW 72H 26/0600Z 30.5N 42.0W 25 KT 30 MPH...POST-TROP/REMNT LOW 96H 27/0600Z...DISSIPATED $$ Forecaster Blake |