{"id": "1218421777789812739", "title": "Tropical Cyclone Discussion", "adv_date": "2026-10-13T15:00:00Z", "msg": "602\nWTPZ41 KNHC 131453\nTCDEP1\n \nTropical Depression Twenty-One-E Discussion Number   1\nNWS National Hurricane Center Miami FL       EP212026\n900 AM CST Tue Oct 13 2026\n \nSatellite images show that the area of low pressure located to the \nsouth of southern Mexico has become better organized over the past \n24 hours.  Large areas of banded deep convection are seen to the \nnorth and the east of the low-level center.  An OSCAT pass from 0630 \nUTC this morning showed a closed circulation, but it was a bit short \nof being considered well-defined at that time since the data still \nshowed a broad and somewhat elongated area of weak winds within \nabout 75 n mi of the center.  However, the convective organization \nand curved banding has increased since that time, and the \ncirculation appears to have tightened up a bit over the past several \nhours.  The subjective Dvorak estimate from TAFB is T2.0/30 kt, and \nit is estimated that a tropical depression has formed with an \ninitial intensity of 30 kt.\n\nThe initial motion of Tropical Depression Twenty-One-E is estimated \nto be northwestward, or 305/9 kt.  A west-northwestward to \nnorthwestward motion should continue over the next 36 hours while a \nmid-level ridge persists over the northwestern Gulf of America.  \nThereafter, a turn to the northwest or north-northwest is likely as \nthe ridge weakens.  A decrease in forward speed is also expected \nafter day 2 as the cyclone gets caught in weaker steering currents \nin between the weak ridge to its north and Hurricane Simon to its \nnorthwest.  Spread in the track forecast is larger than normal from \nday 3 to 5, and some of this uncertainty is likely also due to \nuncertainty in Simon's track.  A cold front moving southward from \nTexas into Mexico toward the end of the forecast period could help \ndraw Simon closer to the coastline of Mexico, if the front is potent \nenough.  Regardless, Tropical Depression 21-E could potentially be \nvery close to the coast of Mexico as a hurricane over the weekend, \nand several Google DeepMind Ensemble members show the cyclone making \nlandfall in southwestern or west-central Mexico.  The NHC forecast \nclosely follows the HFIP Corrected Consensus Approach (HCCA), and \nisn't too far off from the Google DeepMind Ensemble Mean.  \nConfidence in the track forecast is low, especially beyond day 3.\n\nThe cyclone is forecast to traverse extremely favorable oceanic and \natmospheric conditions for at least the next 3 to 4 days.  The NHC \nintensity forecast shows steady strengthening over the next 24 hours \nas the cyclone works to develop a convective core.  After that time, \nrapid intensification is forecast during the 24 to 72 h time window. \nThe DTOPS in the ECMWF-based SHIPS guidance is forecasting a 74 \npercent chance of a 65-kt increase over the next 72 h.  The NHC \nintensity forecast is even more aggressive and shows 85 knots of \nstrengthening over the next 72 h.  The NHC forecast is slightly \nbelow the HCCA and GDMI in the short term, but very near the HCCA \nand GDMI beyond Day 2.  The HAFS-A and HAFS-B models strengthen the \ncyclone to a category 4, and 36 of the 50 Google DeepMind members \nmake it a category 4 or stronger, so the NHC forecast will \naggressively show this system reaching category 4 strength at days 3 \nand 4.  Beyond day 4, the possibility of increasing vertical wind \nshear and land interaction could induce some weakening, and most of \nthe guidance shows the system losing some intensity after day 4.  \nConfidence in the intensity forecast is above average.  We are \nfairly confident it will become a strong hurricane due to the \nfavorable environmental conditions and model guidance.\n\n \nFORECAST POSITIONS AND MAX WINDS\n \nINIT  13/1500Z  9.8N  96.5W   30 KT  35 MPH\n 12H  14/0000Z 10.5N  97.6W   40 KT  45 MPH\n 24H  14/1200Z 11.3N  99.3W   50 KT  60 MPH\n 36H  15/0000Z 12.0N 100.5W   65 KT  75 MPH\n 48H  15/1200Z 12.8N 101.4W   80 KT  90 MPH\n 60H  16/0000Z 13.7N 101.9W  100 KT 115 MPH\n 72H  16/1200Z 14.5N 102.2W  115 KT 130 MPH\n 96H  17/1200Z 16.5N 103.5W  120 KT 140 MPH\n120H  18/1200Z 18.6N 105.3W  105 KT 120 MPH\n \n"}