{"id": "1204332584954855427", "title": "Tropical Cyclone Discussion", "adv_date": "2026-08-24T21:00:00Z", "msg": "597\nWTPZ44 KNHC 242032\nTCDEP4\n \nTropical Storm Iselle Discussion Number   6\nNWS National Hurricane Center Miami FL       EP092026\n200 PM PDT Mon Aug 24 2026\n\nIselle's cloud pattern continues to gradually improve in \ngeostationary satellite imagery despite the moderate \nwest-northwesterly shear in the environment.  The cyclone contains a \ncore of deep convection with an impressive trailing curved band \nextending southward on the east side of Iselle.  Some recent \nmicrowave satellite overpasses show a similar structure.  The latest \nsubjective Dvorak classification from TAFB is T3.5/55 kt, and \nobjective satellite intensity estimates range from 55 to 59 kt.  \nBased on the improving structure, the initial intensity is increased \nto 60 kt for this advisory.\n \nThe initial motion estimate is unchanged from the previous advisory, \nnorthwestward, or 310/11 kt.  A mid-level ridge north of Iselle is \nforecast to strengthen, causing Iselle to turn west-northwestward on \nTuesday, and that motion should then continue through the end of the \nweek.  The latest NHC track forecast is quite similar to the \nprevious one, and lies very close to the HFIP Corrected Consensus \n(HCCA) and the Google DeepMind Ensemble Mean (GDMI).\n \nIselle remains over warm waters and within a moist environment. \nHowever, the cyclone is experiencing moderate west-northwesterly \nvertical wind shear.  Water temperatures and moisture will remain \nquite favorable for another 12 to 24 h, but the shear is forecast to \nincrease slightly to about 20 kt in about 12 h.  Given the recently \nimproving structure, the NHC forecast continues to call for the \nsystem to strengthen to a hurricane in 12 h.  The NHC intensity \nforecast is near the high end of the guidance suite for the first 36 \nh of the forecast.  Beyond 24 h, gradually decreasing ocean \ntemperatures and moisture will lead to steady weakening, and the NHC \nintensity forecast lies in the middle of the guidance envelope from \nhour 48 onward. The latest ECMWF and GFS simulated satellite imagery \nsuggest that Iselle could become a remnant low as early as Thursday. \nThe time of when Iselle becomes a post-tropical cyclone has been \nmoved forward to 72 hours.  After that, the models indicate the \nremnant low opening up into a trough between day 4 and 5.\n\n \nFORECAST POSITIONS AND MAX WINDS\n \nINIT  24/2100Z 19.2N 118.0W   60 KT  70 MPH\n 12H  25/0600Z 20.1N 119.4W   65 KT  75 MPH\n 24H  25/1800Z 20.9N 121.3W   60 KT  70 MPH\n 36H  26/0600Z 21.4N 123.2W   55 KT  65 MPH\n 48H  26/1800Z 21.9N 124.9W   45 KT  50 MPH\n 60H  27/0600Z 22.4N 126.8W   35 KT  40 MPH\n 72H  27/1800Z 22.9N 128.9W   30 KT  35 MPH...POST-TROP/REMNT LOW\n 96H  28/1800Z 23.5N 133.3W   25 KT  30 MPH...POST-TROP/REMNT LOW\n120H  29/1800Z...DISSIPATED\n \n"}