{"id": "1216793074074386439", "title": "Tropical Cyclone Discussion", "adv_date": "2026-10-07T21:00:00Z", "msg": "190\nWTNT44 KNHC 072049\nTCDAT4\n \nTropical Storm Isaias Discussion Number   5\nNWS National Hurricane Center Miami FL       AL092026\n400 PM CDT Wed Oct 07 2026\n \nSatellite and aircraft data show that Isaias continues to \nstrengthen.  GOES-19 imagery indicates that a central dense overcast \nhas formed, and the system has become more symmetric than this \nmorning.  The peak NOAA Hurricane Hunter aircraft 700-mb winds \nwere 61 kt, with the pressure dropping to 994 mb.  The initial \nintensity is set to 55 kt as a reflection of this data.\n \nIsaias is basically on track, moving east-northeast at 7 kt. There \nis no change to the synoptic reasoning as a deepening trough along \nthe northwestern Gulf Coast and a strengthening Atlantic subtropical \nridge should cause the system to move faster to the northeast \ntomorrow and northward on Friday.  As long as the cyclone remains \nintact, it makes physical sense that the system will move on the \nfaster and eastward side of the guidance due to the stronger shear \nIsaias should encounter near landfall.  Thus, the new forecast is \nadjusted slightly to the east, closer to the AI-based and \ncorrected-consensus models.\n \nNOAA radar data (P3-TDR) show that the system is experiencing some \nsouthwesterly shear, with tilt analyses displaying the mid-level \ncirculation displaced 5-10 n mi to the northeast of the low-level \ncenter.  This structure seems sufficient for further intensification \ngiven a continuation of similar low or moderate shear and very warm \nSSTs in a very humid environment.  Models are fairly consistent \nabout the shear increasing on Friday, but almost all guidance still \nshows a category 1 or 2 hurricane at landfall.  While the regional \nhurricane models have generally come down on the peak intensity this \ncycle, it is unknown whether this is the start of a real trend, and \nwe would prefer to see more than one guidance cycle before making \nany adjustments.  The new forecast is close to the previous one, \nnear the high side of the model suite.\n \nKey Messages:\n \n1. Isaias is expected to strengthen and be a strong hurricane when \nit approaches 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 is in effect from \nThe Mouth of the Mississippi River to Yankeetown, Florida. Residents \nin the watch area should follow advice given by local officials and \nevacuate 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 southern \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 through Thursday.\n \n \nFORECAST POSITIONS AND MAX WINDS\n \nINIT  07/2100Z 22.7N  92.9W   55 KT  65 MPH\n 12H  08/0600Z 23.1N  91.8W   70 KT  80 MPH\n 24H  08/1800Z 24.1N  90.1W   80 KT  90 MPH\n 36H  09/0600Z 25.8N  88.7W   90 KT 105 MPH\n 48H  09/1800Z 28.1N  87.6W   95 KT 110 MPH\n 60H  10/0600Z 31.0N  87.3W   60 KT  70 MPH...INLAND\n 72H  10/1800Z 34.0N  87.5W   30 KT  35 MPH...POST-TROP/INLAND\n 96H  11/1800Z 37.5N  84.5W   15 KT  15 MPH...POST-TROP/INLAND\n120H  12/1800Z...DISSIPATED\n \n"}