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Tropical Storm Cristobal Forecast Discussion Number 7
2020-06-03 10:47:22| National Hurricane Center (Atlantic)
Issued at 400 AM CDT Wed Jun 03 2020 000 WTNT43 KNHC 030847 TCDAT3 Tropical Storm Cristobal Discussion Number 7 NWS National Hurricane Center Miami FL AL032020 400 AM CDT Wed Jun 03 2020 Cristobal has continued to get better organized this morning with the development of a small CDO feature over the low-level center, with cloud tops of -82C to -86C developing very near the center. Radar data from Sabancuy, Mexico, also has shown an improvement in the central convective features, along with an increase in convective banding on the west side of the circulation, which previously had been devoid of any significant convection. Reports from nearby Mexican observations indicate that winds of 47-48 kt exist west of the center, which supports an intensity of 50 kt. The same observations support a minimum pressure of 994 mb. The aforementioned surface observation data and radar imagery indicate that Cristobal is now moving southeastward or 140/03 kt. There could be some erratic motion this morning due to land interaction with the inner-core wind field, but the general motion should remain southeastward toward the coast of Mexico. By this afternoon, a turn toward the east is expected, driving the cyclone inland over southeastern Mexico where it could meander for the next day or two. By 48 hours, the global and regional models are in good agreement on the development of a long fetch of southerly flow on the east side of Cristobal between the cyclone's center and a ridge over the Bahamas and Hispaniola, which will act to lift the tropical storm slowly northward toward the south-central Gulf of Mexico. By 72 hours and beyond, mid-latitude ridging amplifies over the southeastern U.S. and the Bahamas, which will increase the southerly steering flow, causing Cristobal to accelerate northward on day 4 over the central Gulf, followed by a turn toward the north-northwest on day 5 near the south-central U.S. Gulf coast. The models are in very good agreement on this overall developing scenario, with only timing differences on when and how fast the cyclone will lift out away from Mexico. The new NHC track forecast is similar to the previous advisory track, and closely follows a blend of the consensus models TVCN and NOAA-HCCA. Some additional slight strengthening remains possible this morning before Cristobal moves inland over southeastern Mexico. Weakening is likely this afternoon and tonight while the circulation after landfall. The intensity forecast leans heavily on just how far inland Cristobal moves. For now, the cyclone is expected to remain relatively close to the warm Gulf waters, which should temper the rate of weakening typically experienced by inland tropical cyclones. But if Cristobal moves as far inland as Guatemala like the ECMWF and GFS models are forecasting, the cyclone would be considerably weaker and the wind field more expansive on days 3-5. The official intensity forecast is basically the same as the previous advisory, and closely follows the intensity consensus models IVCN and HCCA. Key Messages: 1. Damaging and deadly flooding has already occurred 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. 2. Tropical storm conditions will continue along the coast of Mexico where a tropical storm warning is in effect. 3. Cristobal is forecast to begin moving northward across the Gulf of Mexico on Friday, and there is a risk of storm surge, rainfall, and wind impacts this weekend along portions of the U.S. Gulf Coast from Texas to the Florida Panhandle. While it is too soon to determine the exact location, timing, and magnitude of these impacts, interests in these areas should monitor the progress of Cristobal and ensure they have their hurricane plan in place. FORECAST POSITIONS AND MAX WINDS INIT 03/0900Z 18.9N 92.0W 50 KT 60 MPH 12H 03/1800Z 18.5N 91.8W 45 KT 50 MPH...INLAND 24H 04/0600Z 18.3N 91.5W 35 KT 40 MPH...INLAND 36H 04/1800Z 18.5N 91.1W 30 KT 35 MPH...INLAND 48H 05/0600Z 19.3N 91.0W 30 KT 35 MPH...OVER WATER 60H 05/1800Z 20.5N 90.9W 35 KT 40 MPH 72H 06/0600Z 22.2N 90.9W 40 KT 45 MPH 96H 07/0600Z 26.3N 90.5W 50 KT 60 MPH 120H 08/0600Z 29.8N 91.6W 55 KT 65 MPH...INLAND $$ Forecaster Stewart
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