June 5 (UPI) — After Cristobal regained tropical storm status on Friday, the storm continued to strengthen over warm waters of the Gulf of Mexico on Saturday.
The storm has its sights set on the Gulf coast of the United States, where tropical storm and storm surge warnings are in effect.
On Saturday morning, the storm was packing 50-mph sustained winds and was traveling north at 12 mph, with the center of circulation located around 365 miles south of the mouth of the Mississippi River, according to the National Hurricane Center. Most of this past week, Cristobal was a tropical depression crawling across southern Mexico and unloading feet of rain in the process.
The worst conditions are skewed to the eastern side of the storm due to winds high in the atmosphere over the Gulf of Mexico. A plume of tropical moisture associated with Cristobal was fueling showers along portions of the Gulf coast, including along Interstate 10 corridor in the Florida Panhandle, on Saturday morning.
AccuWeather forecasters expect the system to strengthen further over the warm waters of the Gulf of Mexico before striking the central Gulf Coast late Sunday into early Monday. The central Louisiana coastline is the most likely point of landfall.
Ahead of the storm, Louisiana Gov. John Bel Edwards requested President Donald Trump declare a pre-landfall emergency for the state effective Friday.
“We are confident that there will be widespread, heavy rainfall and coastal flooding,” Edwards said in a press release. “I anticipate the need for emergency protective measures, evacuations and sheltering for the high-risk areas … At this time, due to the dangers presented by the COVID-19 pandemic, sheltering activities will need to include non-congregated settings.”
“We are forecasting Cristobal to make landfall over the central coast of Louisiana late Sunday or Sunday evening,” Dan Kottlowski, AccuWeather’s top hurricane expert, said.
Since the system is sprawling in size, and it’s likely to increase in size as it continues to travel over the Gulf of Mexico, impacts from this feature are expected to precede the arrival of the storm’s center by 36 hours to 48 hours, meaning places along the U.S. Gulf Coast could begin experiencing Cristobal’s outer bands well before the storm makes landfall.
Bands of rain from Cristobal were already moving into portions of Florida early Saturday morning, with rain expected to overspread most of the central and northern Gulf Coast throughout the day on Saturday.
At this time, AccuWeather forecasters say Cristobal is likely to make landfall in the United States as a tropical storm.
“A combination of increased vertical wind shear and dry air wrapping around the southern and eastern periphery of the storm’s center will restrict just how strong the storm becomes,” Kottlowski said, adding that the risk of Cristobal strengthening to a hurricane prior to landfall will be greatly limited by these two factors.
Wind shear is the increase in wind speed with height in the atmosphere. Low wind shear can aid in tropical storm development and strengthening, but strong wind shear can cause a tropical system to weaken or limit its development.
“However, Cristobal could have maximum-sustained winds just under hurricane force with hurricane-force-wind gusts as it makes landfall,” Kottlowski noted.
Sustained winds of 50 mph to 60 mph are forecast with an AccuWeather Local StormMax of 85 mph near and to the east of where the storm makes comes ashore. However, large spiral bands from the storm can bring strong gusts well away from the center.
Whether or not the storm makes landfall as a tropical storm or a Category 1 hurricane may matter little in terms of impact. A Category 1 hurricane has maximum-sustained winds of 74 mph to 95 mph. A tropical storm can produce maximum-sustained winds of up to 73 mph.
“We do not expect the slow movement of Barry from last year and the 24 inches of rain it delivered along the central Gulf Coast,” Kottlowski said, referring to a short-lived hurricane that struck the Gulf Coast in July 2019 and triggered widespread flooding.
Cristobal has already picked up speed while pulling away from Mexico, and should continue to move along at a decent pace through the weekend.
Even with Cristobal’s quicker pace when compared to Barry, the amount of rainfall projected with the storm can be enough to cause serious flooding problems along and east of the storm track. A general 6 inches to 12 inches of rainfall is projected with an AccuWeather Local StormMax of 16 inches.
Flooding could occur even in areas that have experienced a rainfall deficit for the year so far. Portions of the central Gulf Coast are currently experiencing moderate to severe drought. Mobile, Alabama, has picked up 21.11 inches of rainfall since the start of 2020, about 7 inches below normal for the year to date or 76 percent of normal.
As the storm strengthens into Sunday, winds will increase throughout the Gulf of Mexico, but especially in shoreline areas from Louisiana eastward to the Florida Panhandle and along the west coast of the Florida Peninsula.
“The increasing winds will lead to an increase in coastal flooding with a building storm surge, well ahead of the center, beginning on Saturday,” Kottlowski said.
AccuWeather is expecting a storm surge of 3 feet to 6 feet near and just east of where the center strikes along the upper Gulf coast of the United States.
“Evacuation orders are generally issued by government officials where the storm surge is forecast to reach 3 feet or higher,” Kottlowski said. “So we expect some evacuations with this, but it is a matter of where the NHC forecasts that level of storm surge.”
Because of Cristobal’s large size, rip currents will increase in strength and number along much of the U.S. Gulf coast this weekend.
“Tropical-storm-force winds could extend outward to 200 miles from the center of the storm, especially on the eastern and northern sides and be reached by Sunday morning from coastal areas of the western part of the Florida Panhandle through the Louisiana coast,” Kottlowski said.
“Residents along the upper and eastern Gulf coast will need to take action to prepare for the arrival of tropical-storm-force winds and building storm surge from Cristobal by Sunday morning,” he added.
The combination of heavy rain and winds that cause a storm surge might be enough to lead to some flooding in New Orleans. The city’s levee system has been significantly upgraded since the Hurricane Katrina disaster in 2005, but storm water pumps failed to handle a torrential downpour that brought 7 inches of rain in 6 hours in July 2019 and led to flooding in the city. Depending on exactly where the bands of heavy rain set up and linger, street flooding in the city is anticipated from Cristobal.
As Cristobal approaches the upper Gulf coast, areas near and to the east of the storm center may be at risk for tornadoes and waterspouts to develop. Cristobal’s big span and dry air that will sweep up from the southwest could be enough to cause rotating thunderstorms to ignite, with the potential for tornadoes to touch down, from late Sunday through Monday. The severe thunderstorms would tend to develop in the spiral bands that extend outward from the storm.
For ultimate safety, small craft along the Gulf coast should remain in port this weekend. Petroleum interests may need to take precautionary measures. Some of the rigs in the region have already been shut down due to the ongoing glut of fuel.
In contrast, due in part to the lopsided nature of the storm and the further flow of dry air into the storm this weekend, rainfall will trail off dramatically west of the storm track. Impact on areas near and southwest of Houston may be limited to breezy conditions with surging temperatures and rip currents on the beaches.
Beyond this weekend, Cristobal is forecast to move inland over the lower Mississippi Valley next week. An area of heavy rain with localized flooding is possible as the storm moves northward and evolves into a tropical rainstorm.
Problems from Cristobal could even continue as far away as the Upper Midwest in terms of flooding rain, strong wind gusts and severe thunderstorms as the tropical storm transitions further into more of a continental storm.
Any flooding could also have an effect on rice crop in the Mississippi Delta, especially since the crop has just emerged. About 65 percent of the total U.S. rice crop is grown in this region, with 40 percent of the U.S. crop grown in Arkansas alone.
Hurricane season just began on Monday, and already the Atlantic has set a new record. Cristobal became the earliest third tropical storm on record when it was named on June 2. The storm beat the previous record which stood from 2016 when Colin formed on June 5.
Cristobal was preceded by Arthur and Bertha, which both formed prior to the official start of the season on June 1. And even more threats could soon arise. AccuWeather meteorologists began monitoring another area of showers and thunderstorms in the Atlantic for tropical development late in the week.
“An area of low pressure could form along a frontal boundary within a region of marginally warm water and could turn into a short-lived subtropical or tropical storm system during Tuesday and Wednesday of next week a few hundred miles to the southeast and east of Bermuda,” Kottlowski said. A subtropical storm is a system that has both tropical and non-tropical characteristics.
AccuWeather is forecasting a busy tropical season in the Atlantic with 14 to 20 tropical storms, including seven to 11 which could strengthen further into hurricanes. Four to six major hurricanes — Category 3 or higher — are predicted.