{"id": "1214385992362491911", "title": "Tropical Cyclone Discussion", "adv_date": "2026-09-29T09:00:00Z", "msg": "346\nWTPZ43 KNHC 290846\nTCDEP3\n \nTropical Storm Rachel Discussion Number   9\nNWS National Hurricane Center Miami FL       EP182026\n300 AM CST Tue Sep 29 2026\n\nRachel has been exhibiting a pattern of bursting very deep \nconvection over the past several hours with cloud tops as cold as \n-90 deg C.  However, the deep convective area has a rather \nshapeless appearance on satellite imagery, and is lacking \nconvective banding features.  The storm continues to experience \nsome north-northeasterly vertical wind shear.  Observations from a \nNOAA Hurricane Hunter Tail Doppler radar research mission indicate \nthat the system is becoming more vertically aligned.  Nonetheless, \nsince the system's satellite signature indicates arrested \ndevelopment, the advisory intensity is held at 50 kt which is a \nlittle above the latest Dvorak estimate from TAFB.\n\nBlending center position estimates from the NOAA aircraft along \nwith geostationary and microwave satellite-base center fixes, the \nmotion estimate is 300/10 kt which is about the same as before.  \nRachel should move along the southwestern side of a mid-level ridge \nwith a more northwestward motion being induced by a 500 mb cutoff \nlow over the southwestern United States during the next few days.  \nBy late week, the trough is forecast to lift out and the ridge \nshould become reestablished to the north, with Rachel expected to \nresume a west-northwestward motion by around 72 hours.  The \nofficial track forecast is slightly south of the one from the \nprevious advisory but on the northern side of the track guidance \nenvelope.\n\nRachel should be moving through a favorable atmospheric \nthermodynamic environment and over generally warm sea surface \ntemperatures during the next several days.  Assuming that the \nvertical wind shear does not become too prohibitive, strengthening \nis forecast.  There is a possibility that the system's \nintensification could be slightly inhibited by some cooler waters \ndue to the wake of Hurricane Polo.  The official intensity forecast \nis close to the simple intensity model consensus, but the corrected \nconsensus guidance is somewhat higher, as noted in the previous \nadvisory discussion.\n\n \nKey Messages:\n \n1. Although the core of Rachel is forecast to remain offshore of\nMexico, tropical-storm-force winds are expected along a portion of\nthe coast of southwestern Mexico in the Tropical Storm Warning area\ntoday.  Tropical storm conditions are possible in the watch area \ntonight or on Wednesday.\n \n2. Outer bands from Rachel will bring locally heavy rainfall to \nportions of coastal southwest Mexico through Thursday. This rainfall \nmay produce areas of flooding and mudslides, especially in regions \nof steep terrain.\n \n3. Large waves could produce life-threatening surf and rip current\nconditions along portions of the southwestern coast of Mexico during\nthe next several days.\n \n \nFORECAST POSITIONS AND MAX WINDS\n \nINIT  29/0900Z 14.7N 104.3W   50 KT  60 MPH\n 12H  29/1800Z 15.7N 105.4W   55 KT  65 MPH\n 24H  30/0600Z 17.1N 106.8W   65 KT  75 MPH\n 36H  30/1800Z 18.4N 108.1W   75 KT  85 MPH\n 48H  01/0600Z 19.3N 109.1W   80 KT  90 MPH\n 60H  01/1800Z 19.8N 109.7W   85 KT 100 MPH\n 72H  02/0600Z 20.2N 110.3W   85 KT 100 MPH\n 96H  03/0600Z 20.7N 111.6W   85 KT 100 MPH\n120H  04/0600Z 21.1N 113.5W   85 KT 100 MPH\n \n"}