A variety of weather hazards will be felt around the Gulf Coast from Florida to Louisiana today, with the situation going downhill as the day progresses as Tropical Storm Cristobal approaches from the south. People in this entire region should be rushing their hurricane action plans to completion.
The National Hurricane Center has issued a Storm Surge Warning for from the mouth of the Mississippi River to Ocean Springs, Mississippi and also for Lake Borgne. A Storm Surge Watch is also in effect from east of Morgan City, Louisiana to the mouth of the Mississippi River. A Storm Surge Warning means there is a danger of life-threatening inundation, from rising water moving inland from the coastline, during the next 36 hours in the indicated locations. A Storm Surge Watch means there is a possibility of life-threatening inundation, from rising water moving inland from the coastline, in the indicated locations during the next 48 hours. The National Hurricane Center warns that “this is a life-threatening situation. Persons located within these areas should take all necessary actions to protect life and property from rising water and the potential for other dangerous conditions. Promptly follow evacuation and other instructions from local officials.”
The National Hurricane Center has also issued a Tropical Storm Warning for Intracoastal City, Louisiana to the Okaloosa/Walton County line in Florida and for Lake Pontchartrain and Lake Maurepas. A Tropical Storm Warning means that tropical storm conditions are expected somewhere within the warning area within the next 36 hours.
As of the latest update from the Miami-based National Hurricane Center, the center of Tropical Storm Cristobal was located near latitude 24.7 North, longitude 90.2 West. Cristobal is
moving toward the north near 12 mph and this general motion is expected to continue for the next day or so, followed by a gradual turn toward the north-northwest. On the forecast track, the center of Cristobal will move northward over the central Gulf of Mexico today and tonight, and will be near the northern Gulf of Mexico coast on Sunday. Cristobal’s center is then forecast to move inland across Louisiana late Sunday through Monday morning, and northward across Arkansas and Missouri Monday afternoon into Tuesday. Maximum sustained winds are near 50 mph with higher gusts. Some slow strengthening is forecast until landfall occurs on the northern Gulf coast. Weakening will begin once Cristobal moves inland late Sunday and Monday. Tropical-storm-force winds currently extend outward up to 240 miles from the center of Cristobal’s circulation while the minimum central pressure estimated from Air Force Hurricane Hunter aircraft observations is 994 mb or 29.36 inches.
Cristobal is a wide storm with wide ranging impacts expected to be felt far away from the storm center and far away from the point of landfall. Storm surge, damaging winds, flooding rains, tornadoes, and rough surf are all expected from Cristobal from Louisiana to Florida and eventually to points north of there.
According to the National Hurricane Center, the combination of a dangerous storm surge and the tide will cause normally dry areas near the coast to be flooded by rising waters moving inland from the shoreline. The water could reach as high as 3-5 feet from the mouth of the Mississippi River to Ocean Springs, Mississippi including Lake Borgne. A storm surge is also expected as far south as Tampa Bay, Florida. The deepest water will occur along the immediate coast in areas of onshore winds and will likely extend along the coast well to the east of the center. Surge-related flooding depends on the relative timing of the surge and the tidal cycle, and can vary greatly over short distances.
Tropical storm force wind conditions are expected within the Tropical Storm Warning area along the northern Gulf Coast beginning late tonight or Sunday morning. Some strong gusts will hit Florida well east of the center of the storm where the heaviest convection currently is.
Cristobal is expected to produce total rainfall accumulations of 4-8″ across the eastern and central Gulf Coast into the Lower Mississippi Valley, with isolated amounts to a foot of rain. Isolated significant river flooding is possible along the central Gulf Coast. Rainfall totals of 2-4″ with some localized amounts up to 6″ are expected across the Mid-Mississippi Valley. This rainfall may lead to flash flooding and widespread flooding on smaller streams across the Lower to Mid-Mississippi Valley. Additional rainfall totals of 1 to 3 inches are expected across the Mexican states of Quintana Roo and Yucatan, bringing isolated storm totals to 25″; this will continue the threat of life-threatening flash floods and mudslides there.
A few tornadoes may occur on Sunday across southern Louisiana, southern Mississippi, southwest Alabama and the western Florida Panhandle. Tornadoes may hit with little to no warning; people in the highest risk area should know where they’d go to protect themselves from the threats of both tornadoes and floods; sometimes heading to a lowest point may not be the safest place due to storm surge or fresh water flooding.
Swells generated by Cristobal will affect portions of the northern and eastern Gulf coast during the next few days. Even after the storm passes, these swells are likely to cause life-threatening surf and rip current conditions. People should avoid swimming in the Gulf of Mexico until water conditions have relaxed over time.
Cristobal is the third named storm of a very active 2020 Atlantic Hurricane Season that only just began on Monday. The season officially runs through November 30, 2020.