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| #1003538 (Received by flhurricane at: 4:45 PM 04.Jun.2020) TCDAT3 Tropical Depression Cristobal Discussion Number 13 NWS National Hurricane Center Miami FL AL032020 400 PM CDT Thu Jun 04 2020 The cyclone`s cloud pattern is quite disorganized, with little deep convection near the center. The current intensity estimate is 30 kt, although this may be generous. Since the center should remain over land into Friday morning, some additional weakening could occur during the next 12-24 hours. A re-intensification trend is expected to commence in 36 hours, assuming that the center moves back into the Gulf of Mexico by then. As noted earlier, the atmospheric environment over the Gulf is not particularly conducive for strengthening, with moderate southwesterly shear and some mid-level dry air. There are a number of arc clouds noted in satellite images over the Gulf at this time, which is indicative of drier air at mid-levels. As in the earlier advisories, the NHC intensity forecast is higher than the model consensus. Due to the limitations in tropical cyclone intensity prediction, there is some uncertainty in the strength of Cristobal when it reaches the northern Gulf coast. The system is turning to the left as it executes a partial cyclonic loop within a broad gyre. Beginning tomorrow night, Cristobal should head northward over the Gulf into a weakness in the subtropical ridge. There has not been much change in the official track forecast, which follows the simple and corrected dynamical model consensus. The ECMWF model does show a little more shift to the left in 3-4 days which is also reflected in the NHC track. This should not be considered as a significant change, however, especially for a broad cyclone such as this one. The global models indicate that Cristobal`s wind field will expand as the cyclone moves over the Gulf of Mexico, and this is reflected in the official wind radii forecast. This suggests that when the storm reaches the northern Gulf coast, the worst conditions may occur at a large distance from the center. Key Messages: 1. Damaging and deadly flooding has already been occurring in portions of Mexico and Central America. Cristobal is expected to produce additional extreme rainfall amounts through the end of the week. The heaviest additional rainfall is expected over far southern Mexico and portions of the Yucatan Peninsula, while also extending along the Pacific coast from Chiapas to Guatemala and El Salvador. This rainfall could cause widespread life-threatening flash floods and mudslides. Refer to products from your local weather office for more information. 2. Cristobal is forecast to re-emerge over the southern Gulf of Mexico on Friday and move northward over the central and northern Gulf of Mexico over the weekend. There is a risk of tropical storm force winds this weekend from Louisiana to the western Florida Panhandle and a risk of dangerous storm surge from Louisiana to the Florida Big Bend. These hazards, along with heavy rainfall, will arrive well in advance of and extend well east of Cristobals center. Tropical storm and storm surge watches could be issued tonight or Friday. FORECAST POSITIONS AND MAX WINDS INIT 04/2100Z 17.5N 90.8W 30 KT 35 MPH 12H 05/0600Z 18.4N 90.3W 25 KT 30 MPH...INLAND 24H 05/1800Z 20.1N 90.2W 25 KT 30 MPH...INLAND 36H 06/0600Z 21.9N 90.5W 35 KT 40 MPH...OVER WATER 48H 06/1800Z 23.8N 90.8W 40 KT 45 MPH...OVER WATER 60H 07/0600Z 25.6N 90.7W 45 KT 50 MPH...OVER WATER 72H 07/1800Z 27.5N 90.9W 50 KT 60 MPH...OVER WATER 96H 08/1800Z 31.0N 92.8W 35 KT 40 MPH...INLAND 120H 09/1800Z 34.0N 92.5W 25 KT 30 MPH...INLAND $$ Forecaster Pasch |