{"id": "1206882660195565571", "title": "Tropical Cyclone Discussion", "adv_date": "2026-09-02T21:00:00Z", "msg": "517\nWTPZ43 KNHC 022042\nTCDEP3\n \nTropical Storm Marie Discussion Number   7\nNWS National Hurricane Center Miami FL       EP132026\n200 PM MST Wed Sep 02 2026\n \nSince the previous advisory, Marie has experienced bit of a hiccup\nin its convective structure, with warming clouds tops near the\ncenter aside from a recent burst wrapping around west of the\ncenter. The most recent microwave pass from this morning showed a\nbanding type eye attempting to form, though it was struggling to\nclose off on its northwest side. In addition, there was an RCM-3\nSAR pass earlier today with an interesting structure, showing a\nsmall core, but with stronger winds occuring along the outer bands\nof Marie's circulation. This structure hints that it might take\nsome time for the inner-core to fully consolidate. For now, the\n18 UTC TAFB Dvorak satellite estimate was T3.5/55 kt, while the\nobjective intensity estimates range from 53 to 67 kt. Thus, the\ninitial intensity will remain 60 kt this advisory, keeping Marie\njust shy of hurricane intensity.\n \nMarie appears to be a little right of the prior forecast track, but\nis still moving off to the northwest, with the estimated motion at\n310/10 kt. Over the next several days, a narrow mid-level ridge\nlocated to the north and northeast is expected to steer the tropical\ncyclone generally off to the west-northwest, gradually slowing its\nforward motion in the process as the ridge slowly weakens. Beyond 60\nh, there continues to be significant cross-track spread that\ndevelops among the model guidance, related to how much an amplified\nmid-latitude trough, off the western United States coast, erodes\nthis ridge. For this cycle, some of the more reliable track aids,\nECMWF, Google DeepMind (GDMI), HCCA, actually show Marie turning\nback westward in the day 4-5 time frame, as the ridge holds to the\nnorth of the cyclone while the mid-latitude trough moves inland over\nthe western United States. However, there remain a minority of\nsolutions that show a more rightward track if the trough fully\nerodes the ridge steering Marie. The NHC track forecast this cycle\nis slightly right of the prior one for the first 48-60 h, following\nthe latest trends in the GDMI and HCCA aids, but now bends a little\nmore westward in days 4-5, also following trends in these aids.\n \nIntensity-wise, the earlier SAR imagery in addition to a partial\nASCAT-C pass show Marie has a broad wind field with a\nlarger-than-normal radius of maximum wind. This could prevent more\nrapid development over the next couple of days despite the favorable\nenvironmental conditions. Thereafter, while sea-surface\ntemperatures (SSTs), diagnosed by SHIPS guidance between 27-28 C,\nappear favorable, some of these waters were recently churned up by\nthe last tropical cyclone along this track (Iselle last week), and\nthe HAFS-A/B hurricane-regional models suggest the large wind field\nof Marie could upwell some cooler waters underneath. Thus the latest\nNHC intensity forecast shows a somewhat lower intensity than\nearlier, peaking at 80 kt in the day 2-3 time frame. This intensity\nforecast favors the hurricane-regional models over the latest SHIPS\nguidance given the potential for ocean upwelling. Marie should be\ncrossing the 26 C SST isotherm after 72 h, and weakening is expected\nto begin in earnest beyond this time period.\n \n \nFORECAST POSITIONS AND MAX WINDS\n \nINIT  02/2100Z 18.0N 112.5W   60 KT  70 MPH\n 12H  03/0600Z 18.7N 113.5W   70 KT  80 MPH\n 24H  03/1800Z 19.5N 115.0W   75 KT  85 MPH\n 36H  04/0600Z 20.2N 116.5W   80 KT  90 MPH\n 48H  04/1800Z 20.8N 117.8W   80 KT  90 MPH\n 60H  05/0600Z 21.5N 119.1W   80 KT  90 MPH\n 72H  05/1800Z 22.1N 120.3W   75 KT  85 MPH\n 96H  06/1800Z 23.5N 122.5W   60 KT  70 MPH\n120H  07/1800Z 23.7N 125.5W   50 KT  60 MPH\n \n"}