{"id": "1216723365572313095", "title": "Tropical Cyclone Discussion", "adv_date": "2026-10-07T15:00:00Z", "msg": "025\nWTNT44 KNHC 071454\nTCDAT4\n \nTropical Storm Isaias Discussion Number   4\nNWS National Hurricane Center Miami FL       AL092026\n1000 AM CDT Wed Oct 07 2026\n \nIsaias has gotten better organized during the past several hours \nwith a large area of deep convection near and northeast of the \ncenter.   Recent Air Force Hurricane Hunter data indicate that the \ncenter is re-forming a bit to the north of the previous advisory \nnearer to the mid-level center, with an estimated pressure of \n1000 mb derived from dropsonde data.  The initial wind speed is set \nto 40 kt in consideration of increase in satellite organization and \nthe 4-mb dropsonde pressure fall, close to the UW-CIMSS SATCON \nvalues and many of the other objective estimates.\n \nThe storm is moving east-northeast at 7 kt.  The motion should\ngradually bend northward and increase during the next few \ndays as a trough along the northwestern Gulf coast amplifies and the\nsubtropical ridge east of Florida builds westward.  This pattern \nshould cause a fast-moving Isaias to approach the northern Gulf \ncoast by Friday afternoon.  Model guidance continues to be \nsomewhat split, with the AI-based models generally on the right \nside of the model envelope, and the physics based models on the \nleft side.   The new NHC forecast is nudged a bit eastward, but \nisn't as far east as the latest HFIP Corrected Consensus Approach \n(HCCA) or Google DeepMind ensemble mean (GDMI).  It is worth noting \nthat many of the stronger solutions tend to be on the eastern half \nof the guidance and faster, which necessitates a variety of watches \nat this time.  \n\nWith the center re-formation, the low- and mid-level centers appear \nto be coming into better alignment.  This structural change could \nfacilitate rapid intensification during the next day or two given \nlight-to-moderate shear along the forecast track, near-record SSTs \nfor this time of the year and a very moist environment.  Near \nlandfall, increasing shear could cause some weakening, but it isn't \ncertain how fast the winds will diminish.  Regardless, Isaias \nshould be growing in size as it approaches the northern Gulf coast \ndue to a trough interaction.  The latest guidance is very close to \nthe last NHC intensity forecast, so little changes were made, and \nthe NHC prediction is just below the corrected-consensus HCCA.\n \nKey Messages:\n\n1. Isaias is expected to strengthen into a strong hurricane before \napproaching the northern Gulf Coast on Friday. There is an \nincreasing risk of life-threatening storm surge along portions of \nthe northern Gulf coast, and a Storm Surge Watch has been issued \nfrom The Mouth of the Mississippi River to Yankeetown Florida.  \nResidents in the watch area should follow advice given by local \nofficials and evacuate if told to do so.\n\n2. The risk of damaging hurricane force-winds is increasing over \nportions of the Florida Panhandle, southern Alabama, and \nMississippi.  A Hurricane Watch has been issued from Bay St. Louis, \nMississippi, to Indian Pass, Florida.  Residents in these areas \nshould prepare for the possibility of long-duration power outages. \n\n3. Isaias will bring areas of heavy rainfall to the central U.S. \nGulf coast and much of the Southeast Friday into the weekend. Flash \nand urban flooding, along with isolated river flooding, will be \npossible.\n\n4. Isaias could bring gusty winds and areas of heavy rain to the \nwestern portion of the Yucatan Peninsula over the next day or so.\n\n \nFORECAST POSITIONS AND MAX WINDS\n \nINIT  07/1500Z 22.4N  93.6W   40 KT  45 MPH\n 12H  08/0000Z 22.7N  92.4W   50 KT  60 MPH\n 24H  08/1200Z 23.4N  90.8W   65 KT  75 MPH\n 36H  09/0000Z 24.6N  89.2W   80 KT  90 MPH\n 48H  09/1200Z 26.6N  88.1W   95 KT 110 MPH\n 60H  10/0000Z 29.2N  87.5W   90 KT 105 MPH\n 72H  10/1200Z 32.2N  87.6W   45 KT  50 MPH...INLAND\n 96H  11/1200Z 38.0N  87.5W   20 KT  25 MPH...POST-TROP/INLAND\n120H  12/1200Z...DISSIPATED\n \n"}