Hurricane Sally weakened overnight to a category 1 hurricane with 85 mph winds, but the slow-moving storm is expected to bring historic flooding to the coasts of Mississippi, Alabama, and the Florida Panhandle on Tuesday through Thursday. A widespread area of 10 – 20 inches of rain is expected, with some pockets of 30 inches, accompanied by coastal storm surge flooding of four to seven feet.
At 2 p.m. EDT Tuesday, September 15, Sally was centered 105 miles south of Mobile, Alabama, headed northwest at 2 mph with top sustained winds of 80 mph and a central pressure of 982 mb. Wind gusts as high as 94 mph were observed late Tuesday morning at the VK 786/Petronius (Chevron) oil rig offshore from Mobile, Alabama (elevation 525 feet). On Monday, the site measured sustained winds of 100 mph, gusting to 117 mph.
Data from the Hurricane Hunters, satellite, and radar showed no significant changes to Sally’s organization over the 18 hours ending at 2 p.m. EDT Tuesday. The hurricane was well-organized, but was having difficulty establishing a complete eyewall in the face of moderately high wind shear of 20 – 25 knots from upper-level winds out of the west. Sally was bringing heavy rains to the Florida Panhandle, Alabama, and Mississippi coasts on Tuesday. Radar-estimated rainfall amounts of 2 – 3 inches had fallen in the Florida Panhandle near Pensacola as of 2 p.m. EDT, with 1 – 2 inches common along the coast of Alabama.
Sally is caught in a region of very weak steering currents, and is expected to move very slowly at less than 5 mph until landfall occurs, which could be any time Tuesday night through Wednesday night. The exact location of Sally’s landfall will not matter that much with respect to its chief threats, which are rainfall and storm surge. A swath of the coast including Mississippi, Alabama, and the extreme western Florida Panhandle will receive the worst of Sally’s rains and storm surge regardless of the exact track of the center. Wind damage, however, will be of greatest concern near and to the right of where Sally’s center moves ashore.
Sally has just about run out of time to build a complete eyewall and embark upon a period of rapid intensification. Increasing wind shear, upwelling of cool waters from below, and interaction with land will all be present between now and landfall to potentially put the brakes on any significant intensification burst that might occur; Sally’s landfall intensity is likely to be between 65 mph and 95 mph.
Regardless of its landfall intensity, the primary damage from Sally is likely to result from the slow-moving storm’s torrential rains. Sally is expected to move at 5 mph or less through Thursday, leading to rainfall measurements in feet rather than in inches.
NOAA’s Weather Prediction Center has placed portions of the Gulf Coast in its “High Risk” category for excessive rainfall. It warned of rainfall rates of up to three inches per hour, and a large corridor of 10 – 20 inches of rain near the coasts of Mississippi, Alabama, and the extreme western Florida Panhandle, with isolated amounts up to 30 inches. There will be a sharp western cutoff to the heaviest rains, as shown in Figure 4, but the exact placement of that cutoff is still uncertain.
It’s not out of the question that an all-time state precipitation record for a tropical cyclone could fall, though these are tough to beat. The current records along Sally’s path are:
Florida: 45.20 inches (Hurricane Easy, 1950)
Mississippi: 32.21 inches (Hurricane Georges, 1998)
Alabama: 37.75 inches (Hurricane Danny, 1997)
Georgia: 27.85 inches (Tropical Storm Alberto, 1994)
Sally’s storm surge is also a major threat, with 4 – 7 feet of surge predicted to the east of where the center moves ashore. Mobile Bay is of particular concern given the high population density along the coast. The surge in the bay is not expected to approach that of Hurricane Katrina of 2005, which brought a storm tide 10.29 above the high tide mark, but flooding may exceed that of Hurricane Nate in October 8, 2017, which brought a storm tide of 5.22 feet.
Tidal range in Mobile, Alabama, is about two feet between low and high tide. The new moon occurs Thursday, and this helped bring one of the higher tides of the month during the 11:37 a.m. CDT Tuesday high tide. Subsequent high tides this week will be progressively lower, bottoming out on Friday about five inches lower than Tuesday’s high tide. High tide Wednesday is at 1:01 p.m. CDT, and at that time Mobile could see its greatest storm tide flooding. Storm tide is the combination of the storm surge and the tide.
Trabus Technologies maintains a live storm surge tracker for Sally. As of 2 p.m. EDT Tuesday, the peak surges measured at NOAA tide gauges from Sally were:
4.8 feet at Shell Beach, Louisiana (east-southeast of New Orleans)
3.8 feet at Pilottown, Louisiana (near the mouth of the Mississippi River)
3.2 feet at Waveland, Mississippi
3.2 feet at New Canal Station, Louisiana
2.7 feet at Apalachicola, Florida
A storm surge of approximately 3.5 feet had moved up the Mississippi River to New Orleans as of 1 p.m. EDT Tuesday, and it is predicted to peak at about 4.5 feet on Tuesday afternoon – a height about 10 feet below the tops of the levees.
Hurricane Paulette scored a direct hit on the island of Bermuda on Monday, with the hurricane’s 40-mile-wide eye encompassing virtually the entire island at 5 a.m. EDT. At landfall, Paulette was a category 1 hurricane with 85 mph winds. The hurricane’s winds increased to 90 mph while Bermuda was in the eye; at 9 a.m. EDT, when the rear eyewall was pounding the island, the National Hurricane Center upgraded Paulette to a category 2 hurricane with 100 mph winds. A weather station in Wreck Road, Bermuda, reported a sustained wind of 80 mph and a gust to 107 mph around 10 a.m. EDT Monday.
Paulette knocked out power to 25,000 of the 36,000 customers on Bermuda on Monday morning. By Tuesday morning, power had been restored to all but 6,000 customers, according to The Royal Gazette. No deaths or serious injuries were reported, though roads were blocked by debris and roof damage occurred.
At 11 a.m. EDT Tuesday, Paulette was a category 2 hurricane with 105 mph winds, speeding to the northeast at 29 mph into the open Atlantic. Paulette has a chance to become a major category 3 storm with 115 mph winds on Tuesday night before increased wind shear and cooler waters induce a weakening trend on Wednesday.
Dry air and high wind shear finally destroyed Tropical Depression Rene on Monday afternoon, in the waters several hundred miles to the southeast of Bermuda.
Tropical Storm Teddy, which formed in the central Atlantic on Monday, was headed west-northwest at 13 mph at 11 a.m. EDT Tuesday with top sustained winds of 65 mph.
Teddy is expected to turn to the northwest on Tuesday night, well before reaching the Lesser Antilles Islands. Large swells generated by Tropical Storm Teddy are expected to reach the Lesser Antilles and the northeastern coast of South America on Wednesday. These swells are likely to cause life-threatening surf and rip current conditions.
Conditions for intensification will be very favorable this week, and Teddy is predicted to be a major hurricane by Thursday night. Bermuda and the Canadian Maritime provinces should keep an eye on Teddy, as the storm could potentially affect them next week.
Tropical Storm Vicky formed on Monday in the eastern Atlantic, about 350 miles west-northwest of the Cabo Verde Islands. Prior to formation, the tropical wave that spawned Vicky brought deadly flooding to Praia, capital of the Cabo Verde Islands, where three inches of rain fell on September 12. The floods killed one person and caused substantial damage to infrastructure and agriculture.
At 11 a.m. EDT Tuesday, Vicky was headed west-northwest at 9 mph, with top sustained winds of 50 mph. Vicky will have highly unfavorable conditions for development through Wednesday, with sea surface temperatures near 26 Celsius (79°F) and extremely high wind shear of 45 – 60 knots. Vicky is expected to be a remnant low by Wednesday night and is not a threat to any land areas.
A tropical wave that emerged from the coast of Africa on Monday was designated 98L by the National Hurricane Center. This wave has favorable conditions for development this week, with moderate wind shear of 10 – 20 knots predicted, along with warm ocean temperatures of 27.5 – 28.5 Celsius (82 – 83°F) and a moist atmosphere. The system has modest model support for development, and is predicted to move west to west-northwest at about 10 – 15 mph, reaching the Lesser Antilles Islands around Tuesday, September 22. It is too early to tell if 98L will affect the islands yet.
In its 2 p.m. EDT Tuesday Tropical Weather Outlook, the National Hurricane Center gave 98L two-day and five-day odds of development of 50% and 70%, respectively. The next name on the Atlantic list of storms is Wilfred, which is the last name on the list.
The National Hurricane Center on Tuesday was monitoring an area of interest over the southwestern Gulf of Mexico, which was producing a few disorganized showers and thunderstorms. Some slow development is possible while this system meanders over the Gulf of Mexico this week. Dry air and high wind shear of 20 – 25 knots are likely to keep this system from developing, but this disturbance did have greater model support for development from Tuesday morning’s cycle of model runs than on previous days. In its 2 p.m. EDT Tuesday Tropical Weather Outlook, the National Hurricane Center gave the disturbance two-day and five-day odds of development of 10% and 20%, respectively.
A non-tropical low-pressure system was located on Tuesday afternoon over the far northeastern Atlantic, several hundred miles northeast of the Azores. This low was designated 99L by the National Hurricane Center and is forecast to move south-southeast during the week, approaching Portugal on Saturday.
This low has marginal conditions for development into a subtropical cyclone, with high wind shear of 20 – 40 knots predicted this week, along with cold ocean temperatures of 19 – 22 Celsius (66 – 72°F). In its 2 p.m. EDT Tuesday Tropical Weather Outlook, the National Hurricane Center gave 99L two-day and five-day odds of development of 10% and 20%, respectively.
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Thank you for the update, Jeff Masters. I really appreciate the writing ability it takes to put all of the information into a well-written form that’s easy to comprehend.
You don’t get to make the same comment more than once. We heard you the first time.
Hurricane Sally has been a northeast heavy laden storm as the NHC and experts predicted. While not annular, Sally has taken on a large eye that has annular characteristics. Allowed Hurricane Sally to fight off the dry air, and may allow it to remain a similar strength till landfall. D-max could lower pressures tonight a little, if the eye were to clear, a final burst of intensity before lanfall is still possible.
Flash flood warnings from Panama City, Florida, to the Mississippi border right now. Many of the areas under flash flooding now expected to get twice the amount they’re already gotten. Landfall early morning or tomorrow afternoon will make a huge difference in how bad the flooding gets. http://radar.weather.gov/lite/N0R/MOB_loop.gif?7a98b2f24410c616dcb75735a0b3280a
To downvote vital information by the legion of trolls here is dangerous and I hope YCC gets this under control and fast.
Thanks for the new article, Doc – especially with the stunning photo of Sally’s cloud layers at the entrance!
Thank you Dr. Masters for giving me more of a heads-up on Invest 98L. I have been living with my wife in Caguas, Puerto Rico for a little over two years, about to move back with her to the Miami area, and am keeping an eye on what is coming this way. We moved here about nine months after Hurricane Maria and at that time street lights at certain major intersections were still not functioning. Even on the highway you relied on your headlights. To this day you can still see certain trees that had their hair chopped off. As a high school teacher, I remember one of my students here saying that they just didn’t take it seriously because the previous storms had diverted before hitting land. As the storm took place in September, their entire school year was seriously affected. My neighbor downstairs described tossing out water in buckets for hours through the night to prevent his home from being overwhelmed with water. People have described it like a bomb passed through here. When they woke up in the morning, all the trees were bare, a scene of devastation. You recall the significant loss of life here. The psychological effect on the people I cannot fathom; only those who passed through it can understand. I admire these people for what they endured. Thank God they have gradually rebuilt and–despite the earthquakes and tremors of the last year which added to their trauma–no storm of the magnitude of Maria has returned. This summer’s first storm was impactful, but it didn’t pack the punch that Hurricane Maria did.
I just discovered this website last night after a Google search, and am very impressed by the beautiful and detailed graphics, such as projections on rainfall, wind speed and the potential pathways of the storms. For a while I have been visiting the National Hurricane Center site regularly, but I appreciate the articles and greater level of detail here. The picture up top of Hurricane Sally is remarkable, and the comment section is also pretty interesting. A website such as yours engages people to be better prepared.
As a former resident of Connecticut who has walked through your campus it is nice to connect with your university. I look forward to returning to this site! May God bless you and the other participants here, as well as the people in the pathway of these storms.
Are you Ok with all those fires in your area?
Things look bad and we are getting lots of reports of devastation. Hope you are OK in your zone.
Just a bunch of filthy air, PM 2.5 is 108-127 either side of me. Mask up and go about your business. At least I can stay inside till I run low on food….
Okay folks after another overly hyped storm Sally everything is done for the year as I’ve been saying for 2 weeks from Paulette everything goes out to sea and follows Paul at
This is a Cat 4 stupid comment. All-time rainfall records might be in reach for a storm that was always predicted to be more a rain-maker than a wind-maker which, oh yeah, hasn’t even made landfall yet – and it’s already “overly hyped”? It’s pretty dangerous to be out right now for a wide swath of coast and it might not even make landfall for another freaking DAY.
And then you have the rest of the year. Last year we had TEN storms after this point. There will be at least two more positive MJO periods before the season starts truly winding down. If you want to make a bet on no more storms, I’ll take your money.
Thank you so much for the informative update and projections of the storm Sally, I do so hope that there is time for all preparations to be completed and that the storm weakens before landfall to the extent that its does not cause too much damage.
Just to make things even bit more interesting, in addition to there being 6 storms in the Atlantic Basin with either names or numbers, there is probably about Thursday going to be a “Medicane” to the south of Italy, which will move over to threaten Greece. This will bring winds of about 100 MPH plus and lots of damage.
I will keep my eye on the situation as people in the Med area are not as aware as you in the USA of the potential damage that these types of storms can bring.
I am still drawing breath and waiting for the odd shower on Friday, they tell me.
Apart from that things are very steady here in Spain and there is a lot of this virus thing about, over 30,000 deaths here now and well over 500,000 cases. Nothing bothering me at the moment and I am just treading water until the phase of life, whatever it should be comes along.
I find it interesting that there has not been much said about evacuation orders related to Hurricane Sally. New Orleans issued an evacuation order for “areas outside the levee system” on Sunday, but today they’re saying city services will be back to normal as of tomorrow. Some areas in Florida’s Panhandle have suggested voluntary evacuations. I assume there are other areas that are mandating or recommending evacuations, but I’m sure not seeing much about that on the internet today.
Thank you…but I think it is still September 15th. Time is flying by not quite so fast that it is already October 15th.
Thank You Dr. Masters for the excellent Update on Sally and the rest of the Atlantic Tropics; this season, and current period, is remarkable and historic. Not going to help (in terms of more storms) that we are hitting the La Nina threshold as well (portion of BOM advisory from today below) with another MJO pulse headed into the Atlantic downstream (around October)
Key indicators of the El Niño–Southern Oscillation are at or approaching La Niña thresholds. This includes further cooling in the central tropical Pacific Ocean over the past fortnight to levels just shy of the La Niña thresholds, while the Southern Oscillation Index (SOI) has been at La Niña values since late August. All climate models surveyed by the Bureau indicate further cooling is likely, and that La Niña thresholds are likely to be met in October and will continue until at least the end of the year.
Jacksonville NWS forecast discussion says:
“The cold front will press through northeast FL Friday night. This willbring a northeasterly wind surge this weekend. This surge maintainsitself over our coastal counties into early next week. Some ofthe guidance is suggesting potential for heavy rainfall alongportions of the northeast Florida coastline this weekend and earlynext week potentially developing a significant flood threat tothe coastal counties of SE GA and NE FL while drier airmass worksinto the interior sections of region. Will need to monitor thisclosely in later guidance through the week.”
I live about 50 miles south of Jacksonville, so I’ll keep an eye on this. The nice part of the forecast is that highs early next week might be only 80 to 85. Sweet!
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