000 WTPZ44 KNHC 172032 TCDEP4 Tropical Storm Madeline Discussion Number 1 NWS National Hurricane Center Miami FL EP142022 300 PM MDT Sat Sep 17 2022 A low pressure system located several hundred miles southwest of the southwest coast of Mexico has very slowly become better organized during the past several days. This system has developed and maintained a well-defined center today, and while it is still strongly sheared, the convective organization now appears to be sufficient to classify it as a tropical cyclone. This is supported in part by Dvorak classifications of 2.0 and 2.5 from TAFB and SAB, respectively. The initial intensity is based primarily on scatterometer data from around 18Z that showed peak winds near 40 kt to the southeast of the cyclone's center. Madeline is currently drifting slowly northward, but a faster northward motion is forecast to begin this evening. A broad mid-level ridge extending from over the Atlantic should be the primary steering feature for the next 24 h or so, until another ridge centered over Texas begins to build on Sunday. That should cause Madeline to turn westward and remain on a westward heading through at least the middle of next week. All of the normally-reliable track guidance agrees with this general scenario, but there is a large amount of uncertainty regarding exactly how fast Madeline will make its turn. While all of the track guidance keeps the tropical storm well offshore of Mexico, this uncertainty will have a big impact on the intensity forecast since Madeline is forecast to turn westward very near the 26 degree isotherm. A relatively southerly track will allow Madeline to strengthen, particularly in the 72-120 h portion of the forecast period when the wind shear may lessen substantially. On the other hand, a northern track could cause Madeline to become a remnant low within the next few days. The NHC intensity forecast is near the multi-model consensus and shows a middle ground scenario where Madeline moves through an environment that would allow it to remain a tropical cyclone but not substantially strengthen. Given the uncertainty in the track guidance and the sensitivity of the intensity to the exact track, the NHC forecast is not very high confidence at this time. FORECAST POSITIONS AND MAX WINDS INIT 17/2100Z 15.9N 106.9W 40 KT 45 MPH 12H 18/0600Z 17.0N 107.0W 45 KT 50 MPH 24H 18/1800Z 18.4N 107.8W 45 KT 50 MPH 36H 19/0600Z 19.5N 108.9W 50 KT 60 MPH 48H 19/1800Z 20.2N 110.2W 50 KT 60 MPH 60H 20/0600Z 20.4N 111.3W 45 KT 50 MPH 72H 20/1800Z 20.5N 112.6W 40 KT 45 MPH 96H 21/1800Z 20.5N 115.0W 40 KT 45 MPH 120H 22/1800Z 20.5N 118.0W 45 KT 50 MPH $$ Forecaster D. Zelinsky