Heavy rain and storms leads to flash flooding this week in the South

Scattered to numerous storms are in the forecast for parts of the South and Southeast this as a cold front stalls then moves very slowly across the region. The cold front, paired with a few upper-level disturbances, will allow for several rounds of showers and storms across the region, leading to areas of excessive rainfall through mid-week.

The rain potential is concerning due to the slow moving nature of the cold front I) allowing numerous storms to move over the same areas, II) high amounts of atmospheric moisture allowing for heavy rainfall rates, and III) recent heavy rainfall across the region. The aforementioned variables will lead to a risk of flash flooding from Texas, east into Georgia.

Tuesday’s flood risk extends from western Texas, through the Mid-South, into Alabama. Spot areas of flash flooding are possible for these areas. A higher flood risk exists from central Texas, into southern Arkansas, northern and central Louisiana, into central Mississippi. If you live in a low-lying, flood-prone area, make sure you’re aware of your surroundings and stay up-to-date with the latest forecast. Never cross a roadway covered by water.

Tuesday’s flood risk

The flood risk continues on Wednesday but shifts farther south and east. The flood risk will extend from coastal Texas, through central and southern Louisiana, into southern Mississippi, southern Alabama, the Florida Panhandle, and southwestern Georgia.

Wednesday’s flood risk

While the rainfall amounts don’t look overly impressive, due to the rate at which the rain will fall, paired with the saturated grounds, flash flooding will be realized for parts of the region. Widespread rain accumulations of 2-3″ will fall from central Texas, east into Louisiana, southern Arkansas, Mississippi, central and southern Alabama, and southern Georgia. Isolated amounts up to 6″ are possible.

Rainfall forecast Southern Plains

Rainfall forecast Mid-South and Southeast

Rain will begin across the Southern Plains and Mid-South early-Tuesday and continue through Wednesday. The rain threat will shift into the Southeast late-Tuesday and continue into early-Thursday. While the flood risk is lower for the Carolinas, a good soaking is in the forecast with many areas picking up close to 1″.

Tropical Storm Andres develops, plus Atlantic Hurricane Season outlook

Tropical Storm Andres developed in the eastern Pacific Sunday morning. This is the earliest Tropical Storm to develop in recorded history in the eastern Pacific. The system is expected to remain over water and eventually weaken. This is a good reminder that the Atlantic Hurricane Season is right around the corner.

The 2021 Atlantic Hurricane Season begins in just under a month, on June 1st. It is time to begin talking about the tropics and preparing for the upcoming season. Despite the official June start date, May cannot be slept on. In 2020, there were two preseason storms. Arthur developed in the middle of May while Bertha developed during the end of May. Over the past decade (2011-2020), ten preseason storms have developed, which is the most in modern record-keeping.

The frequency of tropical cyclones steadily climbs from May to September 10th. Due to the frequency of tropical activity developing prior to June 1st, the National Hurricane Center will begin issuing tropical outlooks on May 15th. 

The 2021 Atlantic Hurricane Season is forecast to be above average. This coming off the most active hurricane season on record with 30-named storms and 6 hurricanes hitting the United States. One of the most well-known and prestigious outlooks was released several weeks ago. Colorado State University announced its 2021 Atlantic basin seasonal hurricane forecast and is expecting an above average season with 17 named storms, 8 hurricanes and 4 major hurricanes. A major hurricane is classified as a Category 3 or stronger. What is most concerning about the forecast is that experts anticipate an above average probability for major hurricanes making landfall along the U.S. coastline and in the Caribbean. 

One of the main factors favoring an above average season is the absence of El Niño. El Niño tends to create a hostile environment over the tropical Atlantic, disrupting the development and strengthening of tropical cyclones. Without El Niño, this favors an above average Atlantic season. Another factor favoring an above average season is warmer than average sea surface temperatures across the basin, especially near the main development region. Parts of the Atlantic ocean are 0.5-degrees warmer than average. Warm sea surface temperatures aid in the development and strengthening of tropical cyclones, which will help boost the numbers above average this season. 

Earlier this year, the northern and western Gulf of Mexico water temperatures were running below average due to the Arctic outbreak in February. Those temperatures have slowly recovered throughout March and April and are not expected to mitigate the numbers this season.

The 2021 forecast from CSU is slightly higher than their forecast last year. Their 2020 forecast predicted 16 storms, 8 hurricanes and 4 major hurricanes. The 2021 forecast from CSU will be revised at the beginning of June. Go ahead and begin preparing for hurricane season now. Create your hurricane kit and make sure your insurance is up-to-date.

Colorful rocket launch this evening for the eastern lower-48

Expect a colorful display Saturday evening as NASA is scheduled to launch a rocket from the agency’s Wallops Flight Facility in Virginia for a special space experiment. This launch will be visible for a good chunk of the East Coast.

The NASA launch was originally scheduled for 8:02 p.m. Saturday, May 8th; however, due to weather, the launch has continually been postponed. This is the 4th attempt at launch. The new launch time is today (Tuesday) at 8:05 p.m. NASA indicates there is just under an hour window for the launch, so a launch just a tad later than 8:05 p.m. may occur. A map provided by NASA suggests the rocket may be visible for a good chunk of the East Coast as well as most areas east of the Mississippi River.

The launch will be visible within 10-seconds of the launch for the Mid-Atlantic, with the Carolinas and Northeast seeing the launch within 30-seconds of the launch, and areas farther west seeing the launch within 60-seconds of the launch time.

Want to view the launch? Good news, no special equipment is required. You will not need a telescope or binoculars. All you need is Mother Nature to allow for clear skies in your area. Unfortunately, weather appears to be an issue again this evening for the launch, but we shall see!

Strong tornadoes possible across the South this week

Another shot for severe thunderstorms and tornadoes, including some strong tornadoes, possible for the South on Thursday. A Level 4 risk of severe thunderstorms is in place Thursday for a good chunk of the South, including Jackson, MS; Memphis, TN; Birmingham, AL; and Nashville, TN.

The severe threat will start west of the Mississippi River early in the day and spread east throughout the afternoon and evening hours. It is possible parts of the Level 4 risk area may be upgraded to a Level 5.

Keep checking back for updates!

Live Blog: Tornado Outbreak Continuous Coverage

Severe Weather Outlook 1

This live blog provides a one-stop shop for our users to get the latest forecasts during the current tornado outbreak. In addition to descriptive graphics, we will also share footage as this event unfolds, along with periodic forecast discussions.

Update: Wednesday, March 17, 2021 at 6:08pm ET (5:08pm CT)
Update: Wednesday, March 17, 2021 at 6:04pm ET (5:04pm CT)

A dangerous tornado is currently passing across I-65, north of Birmingham, between Gardendale and Morris.

Update: Wednesday, March 17, 2021 at 5:04pm ET (4:04pm CT)

As of 3:58pm CT, a confirmed tornado was located near Bull City, moving northeast at 30 mph. This tornado-producing storm will soon begin in infringe on northwestern portions of the Birmingham metro region.

Confirmed tornado heading northeastward toward northwestern portions of the Birmingham, Alabama metro.
Update: Wednesday, March 17, 2021 at 4:43pm ET (3:43pm CT)

That blue dot on the right image indicates that debris is being lofted into the atmosphere by a strong tornado. This is the tornado that was near Brookwood, Alabama around 3:31 pm CT. It’s moving northeast at 20 mph. Radar imagery shared by chief meteorologist Marc Weinberg.

Update: Wednesday, March 17, 2021 at 4:33pm ET (3:33pm CT)

Extensive tornado damage over chicken houses in Wayne County, Mississippi from earlier this afternoon. Photo shared by Brian Emfinger (@brianemfinger on Twitter)

Update: Wednesday, March 17, 2021 at 4:12pm ET (3:12pm CT)

A confirmed and strong tornado remains on the ground with a storm that is now east of downtown Tuscaloosa, Alabama. The tornado is now just north of I-20, moving northeastward toward Brookwood.

Strong tornado moving in Tuscaloosa County, Alabama
Update: Wednesday, March 17, 2021 at 3:54pm ET (2:54pm CT)

A confirmed large and extremely dangerous tornado is 7 miles south of Tuscaloosa, Alabama as of 2:45pm CT. The storm is moving northeast at 30 mph. The National Weather Service has designated this as a particularly dangerous situation.

Radar over Tuscaloosa, Alabama as of 2:50pm CT
Strong velocity couplet on Radar southeast of Tuscaloosa as of 2:53pm CT
Update: Wednesday, March 17, 2021 at 3:40pm ET (2:40pm CT)

Clusters of supercells continue to head northeastward across the outlined region. Though surface temperatures may be slightly lower relative to areas nearby, vertical wind shear is very favorable for strong, potentially long-track tornadoes.

Latest region favorable for strong tornadoes in the near future.
Update: Wednesday, March 17, 2021 at 2:30pm ET (1:30pm CT)
tornado watch for western mississippi, southeastern Arkansas, and northern and northeast Louisiana until 7pm CT.
PDS tornado watch for much of western MS and across parts of northern/northeastern LA and southeastern AR until 7pm CT
Update: Wednesday, March 17, 2021 at 2:22pm ET (1:22pm CT)

The SPC has outlined a region across south-central Mississippi that has rapidly become favorable for the development of strong tornadoes.

Update: Wednesday, March 17, 2021 at 2:16pm ET (1:16pm CT)

From earlier in Wayne County, MS. . .

Update: Wednesday, March 17, 2021 at 1:43pm ET (12:43pm CT)

Another PDS tornado will shortly be issued across parts of western Mississippi, southeastern Arkansas, and northeastern/eastern Louisiana.

Outlined region expected to go under PDS tornado watch shortly.
Update: Wednesday, March 17, 2021 at 1:33pm ET (12:33pm CT)

Analogs indicate strong tornado potentially ongoing in Mississippi currently.

Update: Wednesday, March 17, 2021 at 1:27pm ET (12:27pm CT)

A confirmed tornado has already been detected 10 miles south of Goodwater, Mississippi and will cross over the Mississippi/Alabama state line. The Storm Prediction Center has outlined a region that could face impacts from a strong tornado within the next 1-2 hours or less.

Strong tornado threat exists across parts of the MS/AL border
Update: Wednesday, March 17, 2021 at 12:47pm ET (11:47pm CT)

A PDS tornado watch has now gone live across parts of Mississippi and Alabama until 7pm CT. We will make a better graphic in a bit.

A PDS tornado watch has gone live across parts of Mississippi and Alabama until 7pm CT.
Update: Wednesday, March 17, 2021 at 12:40pm ET (11:40pm CT)

Parts of Mississippi and Alabama now sit under a rare 45% tornado risk. These high probabilities have only been used a handful of times in the past. This means that there’s a 45% chance that a tornado will hit within 25 miles of a given point within the outlined region.

The probability that a tornado will hit within 25 miles of a given point in the outlined regions.
Update: Wednesday, March 17, 2021 at 12:20pm ET (11:20pm CT)

The Storm Prediction will issue a PDS (particularly dangerous situation) tornado watch shortly across parts of Mississippi and Alabama. Breaks in cloud coverage, along with strong, low-level transport of moist air from the Gulf of Mexico, have quickly allowed for the atmosphere to become unstable. Temperatures have already surged well into the 70s to near 80 across central and southern Mississippi.

PDS tornado watch coming shortly for outlined region
Breaks in cloud coverage have allowed for quick destabilization.
Update: Wednesday, March 17, 2021 at 12:00pm ET (11:00pm CT)
Severe weather outlook for Wednesday, March 17.
Severe weather outlook for Thursday, March 18.

Strong, violent tornadoes likely for parts of the South

A dangerous severe weather outbreak will unfold across parts of the country over the next three days. This severe weather outbreak will lead to strong, violent tornadoes, large hail and damaging winds.

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The severe threat will slowly shift east from Tuesday through Thursday.

Tuesday severe thunderstorm outlook
Wednesday severe thunderstorm outlook
Thursday severe thunderstorm outlook

Significant severe weather, strong tornadoes possible across the Mid-South and Dixie Alley Wednesday

Wednesday is shaping up to be the first significant severe weather and high-impact tornado threat for Dixie Alley and the Mid-South. A potent upper level storm system will approach the region, allowing a surface low to develop and intensify, pulling in deep moisture and warm air into the region.

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Upper-level storm system Wednesday afternoon
Surface dew points Wednesday afternoon
Temperatures Wednesday afternoon

With the increased moist and warm airmass at the surface, and colder air moving over the region with the approaching upper-level storm system, the Convective Available Potential Energy (CAPE) will be high in the Mid-South and Dixie Alley. The higher the CAPE values, the more unstable the atmosphere; thus, producing stronger updrafts, leading to more severe weather possibilities.

CAPE Wednesday afternoon (high values are in the gray/green and yellow/orange shaded area)

The approaching upper-level storm system will provide favorable wind speeds and directions across the region. Winds will change directions and speed with height, which provides a favorable environment for severe thunderstorms and tornadoes. This is known as directional and speed shear. Directional shear is wind direction changing with height while speed shear is the change in wind speeds with height.

Strong vertical wind shear is crucial for the development and longevity of severe thunderstorms, and wind shear looks favorable for severe thunderstorms late-Wednesday. From 500 mb (around 18,700 feet) down to 925 mb (around 2,500 feet), the winds change direction and speed, which suggests severe thunderstorms and tornadoes are possible with other favorable atmospheric parameters.

500 mb (around 18,700 feet) winds Wednesday afternoon
925 mb (around 2,500 feet) winds Wednesday afternoon

The aforementioned setup indicates not only significant severe weather is possible but tornadoes are also possible late-Wednesday. When looking at such a setup, it is important to look dive into the history and look at similar weather patterns in the past and investigate what they have produced. This is known as analogs.

Looking at the analogs, they indicate similar atmospheric events in the past have led to strong, long-track tornadoes across the region, so this event needs to be monitored closely! It should be noted: this is still far out so the specifics cannot be identified at this point but that will be ironed out over the coming days.

Severe weather analog
Long-track tornado analog
Significant tornado analog

This is supported by the significant tornado parameter values Wednesday afternoon across the region. The significant tornado parameter is a complex composite index, consisting of multiple ingredients. It factors in 0-6 km bulk wind difference (6BWD), 0-1 km storm-relative helicity (SRH1), surface parcel CAPE (sbCAPE), and surface parcel LCL height (sbLCL). To put this in laymen terms, it’s a great tool to identify where strong tornadoes may occur. High significant tornado parameter values are forecast to be present, which suggest tornadoes, some strong or violent, are a possibility across parts of western Tennessee, Mississippi, and western Alabama.

Significant tornado parameter Wednesday afternoon

While there are considerable questions surrounding this event, it appears thunderstorms will develop early-Wednesday west of the Mississippi River in Arkansas and Louisiana. These storms will move east through Wednesday afternoon into Wednesday evening for areas east of the Mississippi River, including Tennessee, Mississippi, Alabama, and eventually Georgia, and the Florida Panhandle.

Due to the severe potential, the Storm Prediction Center has highlighted the Mid-South and Mid-Mississippi Valley for severe weather Wednesday. A Level 3 risk for severe weather is in place Wednesday for the red shaded area. This includes southwestern Tennessee, eastern Arkansas, northeastern Louisiana, Mississippi, and Alabama. A Level 2 and Level 1 risk surrounds the Level 3 risk in the orange and yellow shaded areas.

Wednesday thunderstorm outlook

Now is the time to prepare! Do not panic but have a plan in place in case a Tornado Watch or Tornado Warning is issued for your area. Make sure you have a few reliable sources to receive weather information from as this event approaches.

It is also a good time to refresh your memory on tornado terminology. A tornado watch means conditions are favorable for tornadoes to form. A tornado warning means a tornado has been indicated or spotted. A tornado emergency means a severe threat to human life and catastrophic damage to property is likely.

Tornado terminology

Historic winter storm to impact Rockies and Plains

A historic winter storm will cripple parts of the Rockies and Plains over the weekend. Some areas will experience feet of snow, which will create significant travel impacts, allow for power outages, as well as damage to trees. A few areas that will see the biggest impacts are Colorado, Wyoming, and parts of Nebraska.

A potent upper-level system is moving over the Southwest. This system will move northeast into the Rockies over the weekend, followed by the Plains early next week. Deep moisture is feeding north ahead of the system, which will contribute to the heavy snow as the moisture is forced up the Front Range of the Rockies.

Current Winter Weather Alerts

A plethora of winter weather alerts have been issued across Colorado, Wyoming, and parts of Nebraska. A blizzard warning is in effect for southeastern Wyoming and the northern Nebraska Panhandle where heavy snow and strong winds will lead to white out conditions. A winter storm warning has been issued for central Colorado, southern & central Wyoming, the southern Nebraska Panhandle, and South Dakota where heavy snow will fall. A winter storm watch has been issued for parts of northwestern Nebraska and southwestern South Dakota for heavy snow potential.

Current winter weather alerts

Snow Accumulations and Impacts

Heavy snow and strong winds are likely for the Front Range of the Rockies and the Plains, leading to whiteout conditions. 1 to 2 feet of snow will fall along the I-25 corridor in the region. The 1 foot totals will extend into the western Plains. Parts of the Front Range may see 3 to 4 feet of snow. Heavy snow accumulations of a foot will extend south into the northern mountains of New Mexico. Denver, Cheyenne, Fort Collins, and Boulder will see significant accumulations.

Colorado and New Mexico snow forecast
Wyoming snow forecast
Nebraska and South Dakota snow forecast

Timing

The winter storm is currently over the Southwest and will begin impacting all of the Four Corners states overnight Friday into Saturday. The snow will also begin impacting slight impacts from the system in the Plains and Front Range of the Rockies overnight Friday.

Bigger impacts will arrive for the Front Range of the Rockies and the Plains Saturday through Sunday. Heavy snow and wind will stick around through the entire weekend, continuing into early-Monday morning before shutting down.

Saturday morning radar
Saturday afternoon radar
Sunday morning radar

Multiple rounds of severe weather to impact central parts of the country over the next several days

Multiple round of severe thunderstorms will impact central parts of the lower-48 late this week through the weekend. Damaging winds, large hail, and isolated tornadoes are all possible with the intense thunderstorms.

A favorable spring-like pattern has setup across the lower-48, which will allow for multiple rounds of thunderstorms over the coming days. Deep gulf moisture has surged north into the Plains. This warm, moist air mass will help feed storms that develop across the region. Several “triggers” for storms will approach the region as the upper-levels of the atmosphere are ripe for thunderstorm initiation.

A potent storm system is out over the West Coast with a strong heat ridge over southeastern parts of the lower-48. This will allow areas of lift, which lead to thunderstorm development, to move out of southwestern parts of the country into the Plains. Each area of lift will lead to thunderstorm development each afternoon.

Thursday

Severe thunderstorms are possible Thursday. A Level 1 risk for severe thunderstorms exists from the Ohio Valley, southwest into northern Oklahoma. The main hazards are gusty winds and hail, but an isolated tornado cannot be completely ruled out. This risk area includes Oklahoma City, Tulsa, Louisville, Cincinnati, and Columbus.

Friday

A higher risk for severe thunderstorms arrives Friday afternoon as the storm system over the West Coast moves east into the Desert Southwest. A Level 2 risk extends from central Oklahoma down into northwestern Texas and the Texas Panhandle. A Level 1 risk surrounds the Level 2 risk. All modes of severe weather are possible. This includes tornadoes, hail, and wind. Oklahoma City, Tulsa, Amarillo, Wichita Falls, Lubbock, and Tulsa are included in the risk area.

Saturday

The severe risk increases over the weekend as the storm system moves toward the Plains. This will elevate the severe risk on Saturday with a Level 2 extending from western Texas, north into south-central Kansas. Tornadoes, hail, and wind are possible late-Saturday. The risk area includes Wichita Falls, Oklahoma City, Tulsa, and the western-half of the Dallas-Fort Worth Metroplex.

Sunday

The storm system moves into the Plains on Sunday, shifting the severe threat farther south and east. It is likely severe storms will continue overnight into Sunday morning just east of I-35, slightly weakening, before regaining strength Sunday afternoon, east of I-45. There is a Level 2 risk for eastern Texas, eastern Oklahoma, northern Louisiana, Arkansas, southern Missouri, and far western Mississippi. The main hazard is wind but an isolated tornado and hail cannot be ruled out. The risk area includes Little Rock, Shreveport, Tulsa, and the eastern-half of the Dallas-Fort Worth Metroplex.

It does appear a severe threat will shift east into Dixie Alley and the Tennessee Valley to start the work week but the details are still being ironed out.

Several days of severe weather expected from the Southern Plains to Mid-South

March 1st was the first day of meteorological spring, and now spring-like thunderstorms are in the forecast over the next several days. Severe thunderstorms will begin over the Southern Plains and slowly spread east into the Mid-South.

The severe thunderstorm event will be triggered by the jet stream plunging south over the western-half of the lower-48. This dip in the jet stream will create a nice uptick in moisture across the western lower-48, including parts of California and the Four Corners states (YAY!). What comes down, must go up! A seesaw will take place. As the jet stream dips over the western lower-48, the jet stream will surge north over eastern parts of the country, which will lead to well above average temperatures.

This pattern will set the stage for severe thunderstorms from the Southern Plains into the Mid-South as gulf moisture and warmth feeds north, east of the Rockies, along with strong winds and colder temperatures slowly spreading east in the upper-levels of the atmosphere.

Severe thunderstorm forecast

Wednesday

The first threat for severe thunderstorms begins Wednesday across the Southern Plains. The main area to see thunderstorms will occur from western Missouri, southwest into central and eastern Kansas, down into central Oklahoma. The main hazards are gusty winds and hail.

Wednesday thunderstorm outlook

Thursday

The severe thunderstorm threat continues Thursday, slightly shifting south. The main area to see thunderstorms will occur from southern Missouri, southwest into southern Kansas, down into central and western Oklahoma as well as western Texas. The main hazards are gusty winds and hail.

Thursday thunderstorm outlook

Friday, Saturday, Sunday

A more impactful severe weather threat begins Friday, continuing through the weekend as the dip in the jet stream out west begins to move east. This will allow the hail and wind threat to continue along with an uptick in the chance for tornadoes.

The enhanced severe threat will begin Friday across far southern Kansas, northern and western Oklahoma, extending down into northwestern Texas.

The severe thunderstorm risk area expands on Saturday from southern Kansas, all of Oklahoma, down through northern and central Texas.

By Sunday, the severe threat slowly shifts east into the Mid-South. Eastern Kansas, southern and central Missouri, eastern Oklahoma, eastern Texas, Arkansas, northern and central Louisiana, far western Tennessee, and far northwestern Mississippi will all be under the gun for severe thunderstorms.

All modes of severe thunderstorms are possible Friday, Saturday, and Sunday.

Friday thunderstorm outlook
Saturday thunderstorm outlook
Sunday thunderstorm outlook

As the dip in the jet stream advances east early next week, the associated cold front will seep into the Ohio Valley and Southeast. The thunderstorm threat will shift east, too, but there are too many uncertainties at this point for a severe hazard to be outlined.

Keep checking back for updates!