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Tropical Depression Cristobal Forecast Discussion Number 12
2020-06-04 16:45:12| National Hurricane Center (Atlantic)
Issued at 1000 AM CDT Thu Jun 04 2020 920 WTNT43 KNHC 041445 TCDAT3 Tropical Depression Cristobal Discussion Number 12 NWS National Hurricane Center Miami FL AL032020 1000 AM CDT Thu Jun 04 2020 With the center remaining inland, Cristobal has continued to weaken, and the cloud pattern is becoming disorganized. The current intensity is reduced to 30 kt for this advisory, and the warnings for the Bay of Campeche coast of Mexico have been discontinued. Assuming that the center will emerge over the Gulf of Mexico in about 36 hours, re-intensification should begin by tomorrow evening. The environment over the Gulf of Mexico is not expected to be very conducive for intensification, with moderate southwesterly shear and some dry mid-level air. Not surprisingly, the intensity guidance, such as HWRF and LGEM, are not very bullish on strengthening. The official forecast remains a little above the latest intensity model consensus. It should still be noted, however, that there is some uncertainty as to the strength of Cristobal when it reaches the northern Gulf of Mexico coast due to the limitations of forecasting tropical cyclone intensity change. The cyclone continues to move slowly east-southeastward, or 120/3 kt. Over the next day or so, Cristobal is likely to move along a partial cyclonic loop while embedded within a broader gyre. By tomorrow night, the system should have begun moving northward into a weakness in the subtropical ridge. This generally northward motion should continue until the center crosses the northern Gulf coast. There have been no important changes to the NHC track forecast, which is a blend of the simple and corrected dynamical model consensus aids. The global models indicate that Cristobal's wind field will expand as the cyclone deepens over the south-central Gulf of Mexico. Therefore, the size of the NHC wind radii have again been increased primarily over the eastern semicircle at 36-72 hours. Indeed, the models suggest 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 04/1500Z 17.6N 91.0W 30 KT 35 MPH...INLAND 12H 05/0000Z 17.7N 90.5W 30 KT 35 MPH...INLAND 24H 05/1200Z 19.0N 90.2W 30 KT 35 MPH...INLAND 36H 06/0000Z 21.0N 90.3W 35 KT 40 MPH...NEAR THE COAST 48H 06/1200Z 22.9N 90.7W 40 KT 45 MPH...OVER WATER 60H 07/0000Z 24.7N 90.7W 45 KT 50 MPH...OVER WATER 72H 07/1200Z 26.7N 90.6W 50 KT 60 MPH...OVER WATER 96H 08/1200Z 30.8N 91.7W 35 KT 40 MPH...INLAND 120H 09/1200Z 35.0N 91.5W 25 KT 30 MPH...INLAND $$ Forecaster Pasch
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