Issued at 400 AM EST Tue Nov 05 2024
000 WTNT43 KNHC 050854 TCDAT3 Tropical Storm Rafael Discussion Number 7 NWS National Hurricane Center Miami FL AL182024 400 AM EST Tue Nov 05 2024 Satellite imagery shows that Rafael is becoming better organized, with convective banding features becoming more prominent, especially over the eastern semicircle of the circulation. Central convection is still a bit limited at this time, with a rather small Central Dense Overcast. An earlier Air Force Hurricane Hunter mission indicated falling central pressure, with maximum winds approaching 50 kt. The current intensity is set at that value, which is slightly above the subjective Dvorak estimates, based on the increasing organization of the system. Another Air Force Hurricane Hunter aircraft will investigate Rafael a little later this morning which should provide a good estimate on the strength of the tropical cyclone. Rafael is moving northwestward, with an initial motion estimate of about 325/11 kt. The tropical cyclone should continue this general motion for the next couple of days, crossing western Cuba and moving into the southeastern Gulf of Mexico. The track guidance is in fairly good agreement for the first 48 hours of the period. Thereafter, the model tracks diverge with an increasing spread between the GFS and ECMWF solutions with time. The ECMWF simulation shows a much stronger mid-level ridge over the southeastern U.S., resulting in Rafael moving into the western Gulf in the latter part of the period. In contrast, the GFS model indicates that ridge will break down in 3-4 days, allowing the system to turn northward. The official forecast lies roughly between these two possibilities and is fairly close to the model consensus. This is just slightly west of the previous NHC track. Given the model spread, there is a less confidence than usual in the 4-5 day forecast. The storm is currently situated in an atmospheric and oceanic environment that is quite conducive for strengthening, with high oceanic heat content, low vertical wind shear, and high low- to mid-tropospheric humidity. The various Rapid Intensification (RI) indices from our model guidance show a significant chance of RI during the next day or so, so the shorter-term official intensity forecast might be a bit conservative. After Rafael moves into the Gulf of Mexico, however, drier air and stronger vertical wind shear should halt the strengthening process. The official intensity forecast is on the high side of the guidance for the 3-5 day forecast, and is similar to the previous NHC prediction. Key Messages: 1. Rafael is forecast to be near hurricane intensity when it passes near or over the Cayman Islands by tonight where damaging hurricane-force winds, a dangerous storm surge, and destructive waves are expected. Rafael should reach western Cuba and the Isle of Youth on Wednesday. A hurricane warning is in effect for this region, where a dangerous storm surge and destructive waves are also expected. 2. Tropical storm conditions are expected in Jamaica through early this afternoon. Tropical storm conditions are possible in the Lower and Middle Florida Keys beginning late Wednesday or Wednesday night. 3. It is too soon to determine what, if any, impacts Rafael could bring to portions of the northern Gulf Coast. Residents in this area should regularly monitor updates to the forecast. 4. Rafael will bring areas of heavy rain across portions of the Western Caribbean through early Thursday, including the islands of Jamaica and the Caymans, along with southern and western portions of Cuba. Flash flooding and mudslides are possible along the higher terrain in Jamaica and Cuba. Heavy rainfall will spread north into Florida and adjacent areas of the Southeast United States mid to late week. FORECAST POSITIONS AND MAX WINDS INIT 05/0900Z 17.0N 78.0W 50 KT 60 MPH 12H 05/1800Z 18.4N 79.2W 60 KT 70 MPH 24H 06/0600Z 20.3N 80.8W 70 KT 80 MPH 36H 06/1800Z 22.2N 82.5W 80 KT 90 MPH 48H 07/0600Z 23.9N 84.0W 80 KT 90 MPH 60H 07/1800Z 25.0N 85.3W 80 KT 90 MPH 72H 08/0600Z 25.8N 86.5W 75 KT 85 MPH 96H 09/0600Z 26.8N 89.0W 60 KT 70 MPH 120H 10/0600Z 27.8N 90.6W 45 KT 50 MPH $$ Forecaster Pasch