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.

Significant severe weather outbreak possible Saturday

Forecast Discussion: A strong shortwave is currently sweeping across the Four Corners region, which has induced the development of a surface low pressure system over the southeast Colorado/northeast New Mexico border. As the strong shortwave closes off into a mid-level low pressure system, the surface low will move into southwestern Kansas over the next few hours. A frontal boundary is currently stalled out across central Missouri, lower Illinois/Indiana and along the Ohio River in Ohio/Kentucky. A very moist environment exists south of the frontal boundary at and near the surface. As the surface low treks across Kansas tonight and tomorrow morning and into Missouri/Iowa late Saturday afternoon, the stalled front will begin moving northward as a warm front, replacing the dry airmass to its north with moisture-laden air. Throughout the day Saturday, surface dew points will increase across southeast Iowa and over the remainder of Illinois, Indiana, and Ohio.

surface analysis

Isentropic lift occurs when warmer air pushes up and over a colder airmass, which can generate precipitation. Isentropic lift, along with embedded weaker shortwaves, will continue to generate rainfall along and north of the soon-to-be warm front tonight into tomorrow morning across much of the lower Midwest. If you take a look at the Storm Prediction Center’s (SPC) severe weather risk area for Saturday, they have an enhanced and moderate risks extending from far northeast Missouri and southeast Iowa into northern/central Illinois, and northwestern Indiana. Please be aware that conditions in the morning (6-8am CT) may not feel like a severe weather day across the enhanced/moderate risk areas. Since the warm front will have not moved through much of the region at this point, temperatures will be somewhat chilly, especially with the rain falling. However, as the warm front surges northward, low-level moisture (humidity levels) will increase rapidly into the afternoon hours.

severe weather forecast

The surface low will move into western Iowa by mid-afternoon, strengthening further as it moves into the region. The region positioned just east of the surface low, ahead of the cold front, and south of the warm front will have the greatest risk of dangerous severe weather, as outlined in the SPC forecast. Rainy weather in the morning hours should move out quickly enough to allow for sufficient daytime heating at the surface. As the mid-level low approaches from the west, mid-level temperatures will cool, which will increase instability within the atmosphere. Surface-based instability allows air parcels (bubbles of air) near the surface and within the low levels of the atmosphere to begin rising. Surface heating and the addition of moisture makes those low-level air parcels buoyant. By cooling the mid-levels of the atmosphere, this ensures that the rising air parcels will remain warmer than the surrounding environment, allowing them to keep rising. This strong rising motion in the atmosphere on Saturday will result in deep thunderstorms developing across the risk zone, which will cause an increased risk for very large hail.

Tornado Risk: The enhanced and moderate risks also have been issued due to the tornado risk tomorrow. Within the treat zone, winds will flow from the southeast at the surface but will veer to the southwest with increasing height. We call this vertical wind shear. The position of the surface low relative to the mid-level low and shortwave will cause this turning of the winds with height. Given higher instability and vertical wind shear, tornadoes, some of which could be EF-2 or stronger, are expected. In fact, long-track tornadoes are possible. Keep in mind that the tornado risk extends southward into the Mississippi Valley ahead of the cold front as well; however, the tornado probabilities across that region will stay comparatively lower.

Chicago Tornado/Hail Risk: You might notice that the SPC only has Chicago under a slight risk; however, residents should watch the forecast closely tomorrow afternoon into the evening. The 18z NAM model is slower with moisture return across the Chicago area. By 5pm CT, the model projects dew points to only be in the mid to upper 40s. To the contrary, the HRRR model guidance has consistently projected dew points to be in the upper 50s or 60°F around the same time in downtown Chicago and well into the 60s in the western and southern metro. Timing matters a lot. If the low levels moisten sooner in Chicago, this could increase the tornado risk across the city, especially in the western and southern metro. Which model do we pick? That’s a tough question, especially when they’re trying to iron out intricate details. From what I can tell, the NAM model keeps conditions a bit cloudier across northern Illinois into the afternoon and even has storms moving through a little earlier than the HRRR model does. On the other hand, the HRRR has more daytime heating across the area, which would likely allow the warm front to advance northward more quickly. In effect, this would give developing and passing storms a much more unstable environment to work with. Honestly, I wouldn’t be surprised if the SPC bumps up the risk across areas closer to Chicago in their next update.

NAM model dew points
HRRR model dew points

Please continue to monitor the situation closely throughout the day tomorrow. These forecasts are never perfect, which means that you should expect some forecast modifications tonight and tomorrow morning.  

Two-Day Severe Weather Event Including A Tornado Risk

Saturday-Early Sunday Morning: A strong shortwave system currently located over the Four Corners region has contributed to the development of a surface low pressure system over Mexico. As the shortwave advances eastward, the surface low will move northeastward across Texas tomorrow. By mid-afternoon, the low should be east of Dallas, TX, and by the evening, the system will begin moving across Louisiana/Arkansas. Widespread moderate rainfall will accompany this low across western Texas and across most of Oklahoma, but the primary concern for a potentially significant severe weather event is farther east into eastern Texas, northern Louisiana, southern Arkansas, and west-central Mississippi. Later into Saturday evening and early Sunday morning, the severe weather threat should continue across central-eastern Mississippi.

Aside from the light to moderate rainfall moving across northeast Louisiana and west-central Mississippi this evening, conditions across much of the Mid-South are quite pleasant. A frontal boundary associated with the previous storm system that dumped high snowfall amounts across the Plains and Upper Midwest is currently draped across the lower Mid-South. Since the frontal boundary never really had the opportunity to move well off the Gulf Coast, it won’t take much time for the low-level atmosphere to moisten as the surface low advances eastward over Texas. Dew points are only in the 40s and 50s across eastern Texas, northern Louisiana, and southern Arkansas this evening, but southerly/southeasterly winds will help bring dew points back into the upper 60s and 70s by tomorrow afternoon. Sufficient low-level moisture is a necessary ingredient for severe weather to occur.

Projected dew points on Saturday afternoon

Sometimes, morning thunderstorms and rainfall can help limit a severe weather risk if the atmosphere does not have adequate time to recover and become unstable. However, this should not be an issue tomorrow. Most of the widespread rainfall will remain mainly west of the Midsouth, and if morning activity develops across the region, it should remain scattered enough that plenty of daytime heating will still occur. Since the mid-level environmental temperatures will be quite cold (something that will actually contribute to more instability), temperatures around 70°F should be sufficient for moderate instability.

Projected radar for Saturday afternoon

Given sufficient instability and favorable wind shear profiles, a tornado risk exists across eastern Texas, northern Louisiana, southern Arkansas, and west-central Mississippi. Some tornadoes could be strong. Additionally, large hail and damaging winds will cause issues. The Storm Prediction Center has included a moderate and enhanced risk across those areas. If you are the risk zone, please plan accordingly, and ensure that you have a place to take shelter if a tornado hits your hometown.

Saturday severe weather outlook from the SPC

Sunday-Sunday Evening: The surface low will continue advancing northeastward on Sunday and eventually move across the Ohio Valley. Given this track, a broad and elongated severe weather risk will exist across a large part of the Southeast and extend into the lower Ohio Valley. The Storm Prediction Center has placed an enhanced severe weather risk from Alabama and Georgia northward into southern Ohio. A squall line will eventually develop and move eastward later Sunday or early Monday morning just ahead of an advancing cold front. Though the squall line will primarily pose a damaging wind risk with isolated tornadoes, the bigger tornado threat will exist ahead of the squall line during the day on Sunday, where thunderstorms could be more discrete. Comparatively, the tornado threat may not be as high as on Saturday; however, sufficient instability and wind shear should favor the development of tornadoes across parts of the slight and enhanced regions on Sunday. I will provide a follow-up update for the Southeast tomorrow evening. After monitoring how everything evolves tomorrow and tomorrow night, I expect I will have to make some modifications on the magnitude of the Sunday tornado risk. As suggested above, please have a plan in place.

Sunday severe weather outlook from the SPC
Tornado sheltering guidelines recommended by FEMA

-Meteorologist Matthew Holliday

Tropical Update: Harvey and Hurricane Safety

Hurricane Harvey, now 115 miles southeast of Corpus Christi Texas, has seen the maximum sustained winds increase to 110 this morning, just shy of major hurricane status. The minimum central pressure has dropped 947 Millibars. Harvey is expected to become a major hurricane today with winds increasing further to 120 mph. As of this 11 AM EDT, the following watches and warnings are in effect.

A Hurricane Warning is in effect from Port Mansfield to Sargent Texas. Hurricane conditions will be occurring in these areas within the next 12-24 hours.

A Tropical Storm Warning is in effect from south of Port Mansfield to the Mouth of the Rio Grande River and from North of Sargent to High Island Texas

A Tropical Storm Watch is in effect for South of the mouth of the Rio Grande to Boca de Catan Mexico

A Storm Surge Warning is in effect from Port Mansfield to High Island Texas. A Storm Surge Warning means there is a danger of life-threatening inundation from rising water moving inland from the coastline in the indicated locations. 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.

A Storm Surge Watch is in effect from south of Port Mansfield to the Mouth of the Rio Grande. A Storm Surge watch means there is a possibility of life-threatening inundation from rising water moving inland. Persons located within these areas should take all necessary actions to protect life and property and be on the look out for rising seas.

Forecast Information

Harvey

Hurricane Harvey continues to increase in strength this morning and is now approaching major hurricane status. Harvey is expected to be a category 3 storm when he moves ashore in Texas. Sustained winds are expected to be between 120 and 130 miles per hour with higher gusts. Harvey will be bringing life-threatening storm surge, rainfall, and wind hazards to portions of the Texas coast. Preparations to protect life and property should be completed this morning, as tropical storm force winds will first arrive in the hurricane and storm surge warning areas later today.

Life-threatening storm surge flooding could reach heights of 6 to 12 feet above ground level at the coast between the north entrance of the Padre Island National Seashore and Sargent. Devastating and life-threatening flooding is expected across the middle and upper Texas coast from heavy rainfall of 15 to 25 inches, with isolated amounts as high as 35 inches, from today through next
Wednesday.

Harvey will hug the coast after he moves inland, which could help prevent the quick weakening associated with land falling hurricanes. While Harvey will still weaken, it may be a slower process and he could maintain Tropical Storm strength longer than usual. Harvey is forecast to impact this area for several days.

Hurricane Harvey Hazards

Storm Surge and Storm Tide

Storm Surge and large waves are the greatest threats to life and property along the coast. A storm surge is an abnormal rise of water generated by a storm’s winds. Many will remember the surge from Hurrican Ike is 2008. Storm Surge with Harvey is expected to be as high as 12 feet in some locations (was 20 feet in Ike). Please check your local media sources for the exact surge totals expected for your area. Surge related flooding will be dependent on the exact timing and the tide and can vary greatly over short distances. Large waves will also be a factor at the coast. Based on the tide charts, Harvey should hit as tides are moving out and close to low tide, but onshore winds are possible during several tidal cycles.

Tornadoes

Hurricanes frequently produce tornadoes, usually in the embedded thunderstorms in the rain bands now beginning to hit the Texas coast line. They can also be associated with the eye wall. Tornadoes produced by these systems are usually weak and short lived, but they can be a threat to where they hit. A Tornado watch is expected to be posted for coastal areas of Texas and Louisiana later today.

Winds

It goes without saying that winds are a major issue with Hurricanes. Sustained winds with Harvey are expected to reach up to 120 mph with gusts reaching as high as 150 mph with some locally higher gusts. Harvey is forecast to be a major Hurricane at landfall.

Rainfall

Forecasts for Harvey have indicated significant rainfall is possible, with some models showing over 30 inches of rain. This will be a very long duration event and flooding and flash flooding will bea major issue for many areas.

Hurricane Safety

Evacuations

Many areas in Texas have had evacuation orders given, for those who are evacuating, you will need to determine a safe evacuation route inland. While evacuating, you’ll want to monitor the latest information to ensure that you will be evacuating to a location that is not also under a risk. Public services in these areas will already be strained and adding many evacuees will only cause more strain for everyone. Learning the location of official shelters will be helpful both in the event that you evacuate as well as for those who do not evacuate. Areas that are not under evacuation orders should also have shelters for the residents who end up in trouble due to hurricane hazards. Tornadoes, lightning, power outages, and property damage due to falling trees can force residents from their homes, even if a mass evacuation isn’t needed. The good news is that a quick check of traffic in this region doesn’t show any, so many heeded these orders in advance.

When evacuating, put together a go-bag. Include a disaster supply kit, including a flashlight, batteries, cash, first aid supplies, medications, and copies of your critical information if you need to evacuate. Snacks and stuff to drink will also be good for longer evacuations, especially with children. While you may stop for gas, many others are also evacuating with you so its possible that many supplies will be sold out along your route. If you haven’t already, fill up your gas tank in your local area, gas supplies may also be strained along your route. Cell phones should be charged before you leave. Have one member of your family turn their phone off while travelling together. This will ensure that if one phone does run out of battery, you will have another phone to turn on and use. All family members should have all numbers for your phones and know to call multiple numbers if they can’t get a hold of you.

You should also inform someone of your plans. If you fail to arrive at your destination due to a car accident, your contact can alert the authorities. Having them know the route you planned to take is essential in locating you.

Stay tuned to local news outlets as you travel. Conditions may change and areas you were heading to that were going to be safe may not be anymore. Harvey is brining a large area of rain to Texas and the location you were heading for may end up under a flood warning when it wasn’t before. Always ensure that the safety of your location is the top priority.

Staying at home

For those of you who are not leaving home, I would first implore you to heed local evacuations if you are under them. Evacuation orders are given for a reason. If you are under those orders it is absolutely not safe where you are. While I do realize that some properties remain even in massively damaged areas, you only put yourself and those who would need to rescue you in the event of an emergency in danger by taking that gamble. It is never just your survival on the line.

If you have not been ordered to evacuate, there are several things you should plan for. First, as I mentioned above, have a plan to be able to evacuate to a local shelter if your house if one of the unfortunate locations that falls victim to one of the more local hurricane hazards. Lighting occurs frequently within a hurricane and can strike even in areas where hurricane conditions are not occurring. You should also have a plan for any pets you may have. Not all shelters accept pets so ensure the one you may go to does.

What to bring to the shelter

You will need to make sure that you have everything you need at the shelter. While the shelter will have supplies, they don’t usually carry specific medications or your specific brand of baby food. Ensure that you have a first aid kit with all the medications taken by your family. If you are running low, see if your local pharmacy can give you more. Baby food and diapers will be needed. Your baby should be prepared for a multiple day stay at the shelter. Bring things to do as well. Books, games for children, headphones and a source of music (we all know some of you still have a Walkman) will all be desired. The shelter is not exactly a fun place to be. Bring your toiletries and blankets. The shelter will have some but we all prefer our own. Flashlights and batteries are good to have in case the power goes out at the shelter as well. Also ensure you bring identification, cash and credit cards as well as copies of your essential documentation like proof of insurance.

Protecting your home

Be aware that Hurricane winds can cause trees and branches to fall, so before a hurricane trim or remove damaged trees and limbs to keep you and your property safe.
Secure loose rain gutters and downspouts and clear any clogged areas or debris to prevent water damage to your property. When it comes to repairing your rain gutters, it’s as easy as checking out sites such as https://www.aluminiumwarehouse.co.uk/, finding the right materials and replacing your damaged/old gutters. This will help protect your property, which is what you need to consider, especially after weather conditions like thunderstorms and heavy rain. This can also help keep them lighter and not fall under the weight of all the rain. Reduce property damage by retrofitting to secure and reinforce the roof, windows and doors, including the garage doors. Plywood over windows or close storm shutters if your house has them, this can protect them from wind and debris. If you are construction inclined, hurricane clips can be installed in your attic to help secure your roof to the house. You may also want to get in touch with a home improvement service similar to Mastershield Atl that may be able to provide support for homeowners who are looking for a way to protect their roof from water damage. While it is certainly too late to hire a contractor to do this for Harvey, other storms will come along and this can be done for future storms. You can also brace your garage door and doors that lead outside with planks to keep it from blowing in. You should also close all interior doors to compartmentalize the house. This way, if a window does break in one area, the remaining areas will have protection against the elements coming in. Purchasing a portable generator or installing a generator for use during power outages is also a good idea. Remember to keep generators and other alternate power/heat sources outside, at least 20 feet away from windows and doors and protected from moisture. You should never try to power the house wiring by plugging a generator into a wall outlet. If power does go out, use a flashlight. Candles are a fire hazard.

Keeping food and water safe

The most important thing when it comes to food is to buy nonperishable goods and to store water. You do not need to buy multiple gallons of water for activities like brushing your teeth. Simply refill an old milk or water bottle with tap water and use it. You can do the same thing for bath water, pre-filling your tub is also recommended. Tap water storage can be done with any container from large pots used for cooking to old bottles and even any large plastic container. Always remember to keep using the tap water until it goes out, you don’t want to needlessly use up your supply and not be able to replenish it. For any cold food you do have, turn your refrigerator and freezer to their maximum cold settings and open them as little as possible. This will help keep things cold. Try to use up any chilled foods first so that keeping things cold becomes unnecessary and have a supply of ice on hand to keep things cold longer. While you can buy ice at the store, you can also just use ice cubes. Simply dump your tray into a plastic bag and refill the trays. Dump new ice cubes as they form and keep refilling the trays. You will be able to continue this process for as long as you have power or tap water. This also creates an emergency water supply should you run out of water. Simply melt the ice. You can also use rain water if you have a safe way to get a bucket outside to collect some. You should always try to keep a lid on your water supply. This will keep dust and bugs out of it.

After the Storm

It will be tempting to go outside after the storm has passed or during the calm period in the eye. This should be avoided. The eye is only temporary and hurricane conditions can start very quickly. After the storm, there will be a lot of damage in the region. Floods could still be occurring and the water could be contaminated. You also can’t see what’s in the water. Animals and hazards in the water could be potentially dangerous to your health. The water could even be electrically charged from downed power lines.

We here at Firsthand will do our utmost to keep you up to date with the latest information. Our thoughts go out to those in the areas affected by Harvey. Stay safe everyone.

Robert Millette

Incident Meteorologist

Braintree Emergency Management Agency

Severe weather moves from the Plains towards the Mid-Atlantic

Severe weather is a risk over the next couple of days from the Plains and Gulf Coast regions into the Appalachians towards the Mid-Atlantic.  While there is a low risk for tornadoes, there are significant risks for widespread damaging winds and  large hail.

A stationary front has been the focus for strong to severe thunderstorms over the Plains in recent days bringing over 900 reports of severe hail and wind from Texas to Wisconsin.  This front is interacting with a strong, fast moving cold front that will create the lift needed for a large area of showers and thunderstorms.  Some of these storms could be intense this morning as remnants of a Mesoscale convective system died out overnight across the Plains persists.  The severe weather moves on into the Appalachians by Sunday, and on to the Mid-Atlantic up into New England for Monday.

Saturday

The cold front, along with a strengthening low pressure system, will continue to progress southeastward from Central Iowa into Central Kansas.  The air ahead of this front remains warm and unstable with plenty of moisture.

Storms are likely to begin over Iowa and northern Kansas before spreading East from Michigan down into Missouri.  These thunderstorms are expected to form into linear squall lines over time due to weak low level shear yielding outflow dominant storms.    Any storms should begin to weaken after nightfall as they move east, where lapse rates will be lower.

Sunday

Scattered thunderstorms, with a primary risk of damaging winds, are expected from the Great Lakes into Northeast Texas.  The low pressure from Saturday will move from the Great Lakes into Canada but the cold front will remain across the Ohio Valley into the Southern Plains.

From the Great Lakes down through Tennessee, early remnants from overnight storms should clear with a moisture rich warm air-mass in place to meet the weakening cold front.  The ongoing wind regime should allow for strong multi-cluster cells to form.  Hail may also fall but will only be locally severe.

Further south, storms will be more isolated from the Texoma region into Arkansas.  Lift in this region will be weaker but the cold front will be a focus point for thunderstorms due to an elevated mixed layer and moist low level conditions.  These will form a very unstable boundary layer that could see the convective available potential energy (CAPE) approach 4000 Joules per kilogram.

In Mississippi and Alabama, scattered thunderstorms will develop during the daytime heating period.  Seasonably warm and moist air will become more unstable under conditions that have very little convective inhibition.  Strong to severe cells that do form will likely have marginally severe hail and localized damaging winds.

All southern storms should begin to weaken during the evening hours as daytime heating fades.

Starting off the work week, the Northeast and Mid-Atlantic are looking at pending severe weather as the cold front pushes east into more warm moist air Monday afternoon into the overnight hours effecting all the major metropolitan areas.

Rob

 

 

Moderate Risk for severe weather across the Plains

Severe weather is expected from the Red River Valley through the Ozarks and into the Tennessee valley.  Large to giant hail, widespread severe wind gusts and Tornadoes are anticipated.

A mid-level trough is moving into the northern Plains and will continue to advance eastward.  The trough should reach the upper Mississippi and Missouri Valleys by tonight.  This trough will bring several smaller disturbances across the Plains and mid to upper Mississippi Valley today.

In the western portions of the risk area, from Central and Eastern Oklahoma as well as northern Texas, there will be strong capping in place.  That cap will prevent storms from forming earlier in the day but as lifting forces increase throughout the afternoon, some storms will form and develop rapidly due to favorable profiles.   The overall risk is lower from the Red River Valley up into Northeastern Oklahoma due to this cap, which will allow the cold front to form a line of storms, but any supercells that form before the passage of the front has the potential to be dangerous.  Strong tornadoes and giant hail are risks in these supercells, though the risk becomes more limited the further south you go into Texas.

Further north and east, The potential exists for a swath of damaging wind gusts to occur from eastern Kansas to the mid Mississippi Valley this afternoon and evening.  There are some questions about the development of storms along an outflow boundary this morning from the current storms taking place.  Additional storms this morning would help limit the risk in this area, but capping over the area is expected to keep the number of early morning storms low and keep the risk higher this evening.  Do not be surprised if the Storm Prediction Center puts out an area of high risk later on this morning if only small amounts of convection form and a better location for the deep convection is ascertained.

This convection will all begin to take a linear form as the cold front continues to push east and a convective complex is possible along the cold and warm front that’s will be in the region.  This will approach the Mississippi Valley this evening and into tonight.

 

Rob

Severe Weather from the Plains to the Great Lakes

The severe weather season has gotten off to an active start this year.  After a couple of quiet days, we once again have a risk for some severe storms from Oklahoma up into the Mid Missouri Valley and Upper Mississippi Valley.  Large hail and damaging winds will be the primary threats with very large and damaging hail possible from southern Kansas to Southwestern Oklahoma.  A tornado or 2 can also not be ruled out.  These storms should initiate later this afternoon into this evening and will be widely spaced.  Clusters of development should form in places but see several dozen miles in distance to the next cluster of storms.

Severe Risk

severe

Hail Risk

The biggest risk today is hail, with the largest risk over the Plains.  A strong cap on storms there will make any updrafts that do occur very strong.

Upper Mississippi Valley and Missouri Valley

Widely Scattered Storms will occur late this afternoon on both sides of the warm front that extends from Eastern Nebraska to Southern Wisconsin.  Thunderstorms should also form as the cold front moves into the region down to the Missouri Valley.  Conditions are marginal for supercell development but weak flow will allow those storms to quickly form squall lines of storm clusters.

 

Central and Southern Plains

Any risk further south is much more conditional and local than the river valleys.  The dryline is weak this morning and though it will sharpen, the strong cap will provide plenty of inhibition to storm formation.   Any storm that does form will have a strong updraft capable of producing very large and damaging hail.  Given the isolated nature expected of these storms, the significant risk for hail area covers this region.

For Nebraska and Southern areas of south Dakota, storms will not be prolific rain producers.  While rain could fall heavily in storms, moisture is in very short supply for this region.  The cold front could still help support a few clusters of storms though and large hail is the primary risk.

 

Rob

Severe weather shifts east into the River Valleys

An upper low currently crossing eastern Kansas is forecast to accelerate eastward across Missouri and into the Midwest by tonight.  This system, along with a shortwave trough moving into the Gulf of Mexico will quickly shift a cold front across the southeast.  This front is expected to be span from the Ohio Valley down to the Florida panhandle by Friday morning.

Current Conditions

 

Currently, the last of the Tornado Watches has expired.   Strong to severe thunderstorms continue to shift east through Louisiana and Mississippi with a few strong storms up in Illinois.  The storms in Illinois should weaken this morning,  but the southern storms across the gulf states will remain locally severe.

Cloud cover from the current storms will help limit some of the day time heating this afternoon.  The Storm prediction center had a moderate risk area in the forecast yesterday.   This has been downgraded to enhanced this morning.  Do not be surprised if a smaller area of moderate risk re-appears this afternoon as the location of the most destabilization becomes obvious.   The entire area should see at least some instability along and ahead of the cold front, which should be along the Mississippi River by Midday. This front will shift east and provide the mechanism by which storms will form.

Severe Risk

New storm development is expected my early to mid afternoon.  Rotation should be limited with height, but speed shear should generate enough rotation to make tornadoes a risk for a large area as rotating supercells and small bow echoes become possible, particularly over the lower Ohio Valley.

Expect hail and strong winds to remain a risk from this afternoon into the overnight hours near the Appalachians.  The risk will shift even further east into the D.C. area by Friday.  The system should be much weaker with a lower risk for severe weather at that time.  The northeast will even be experiencing snow Friday into the weekend.

Severe weather risk continues for the next few days

After yesterday’s severe weather across parts of Oklahoma and Texas, storms have spread to the east.  Severe Thunderstorm watches are in effect across several states from now until tonight.

Severe Risk

A trough across Missouri this morning moved eastward to the middle Ohio River Valley and will arrive by late tonight. A belt of 40-50 kt west-southwesterly mid level winds will continue to overspread an increasingly moist warm sector. A cold front has moved across the Ozarks and Ark-La-Tex region and continues east through Kentucky and Tennessee down to the Gulf Coast.  Organized convection across far northeast Arkansas far southeast Missouri from late this morning has spread east-northeastward and increased in coverage and intensity into Tennessee and Kentucky. This activity will pose a damaging wind and severe hail risk, although a tornado cannot be ruled out.

Farther south, more discrete storms have developed within the warm sector this afternoon across additional portions of Tennessee, northern Mississippi and northwest Alabama.  A supercell-favorable wind profile and steep mid-level lapse rates will support large hail potential. A few tornadoes also appear possible,  particularly into early evening across middle portions of Tennessee and northern Mississippi and northwest Alabama.   In this corridor, a modest westerly component of the mid-level winds  and modestly strong low-level shear coincide.

Severe

Tornado Risk

Hail Risk

Wind Risk

Current Watches

A Convective line stretching from near Huntingburg Indiana southward across central Kentucky and middle Tennessee and into northwest Alabama is expected to continue moving eastward over the next few hours. The downstream airmass is generally cooler and has less overall instability. However, the line is well-organized and the bulk shear
is expected to remain relatively constant for the next several hours. Near-severe gusts have been measured at several sites as the line moved through. The ongoing severe threat will persist for the next few hours.  A threat is possible downstream in eastern Kentucky, Tennessee and far northwest Georgia and a watch has been issued for this region.  Additionally, the cluster of storms ahead of the line in eastern Kentucky pose an isolated hail and damaging wind threat.

Current warnings

 

 

Robert Millette

 

Tornado Outbreak expected in Southeast

A significant Tornado outbreak and Severe Thunderstorm outbreak is expected across many areas in the Southeast, from Florida back into Alabama up through Georgia, South Carolina and parts of North Carolina.    The biggest risk is from northern Florida into Southern Georgia with smaller risks as far west as Eastern Mississippi up into Southern Virginia.

Tornado Outbreak forecast

Significant Severe Tornadoes expected

Tornado Outbreak
Day 1 Tornado Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
SIG SEVERE 95,336 13,200,743 Columbia, SC…Charleston, SC…

St. Petersburg, FL…Orlando, FL…

Savannah, GA…Gainsville, FL

30 % 52,311 4,824,800 Jacksonville, FL…Tallahassee, FL…

Savannah, GA…Gainesville, FL…

Albany, GA…

15 % 44,337 9,370,344 Tampa, FL…St. Petersburg, FL…

Columbia, SC…Clearwater, FL…

Charleston, SC…

10 % 42,022 5,926,863 Orlando, FL…Columbus, GA…

Fayetteville, NC…Wilmington, NC…

Lakeland, FL…

5 % 81,803 21,852,295 Charlotte, NC…Atlanta, GA…

Miami, FL…Raleigh, NC…

Greensboro, NC…

2 % 48,102 6,722,417 Virginia Beach, VA…Norfolk, VA…

Birmingham, AL…Chesapeake, VA…

Winston-Salem, NC…

High Risk issued for Severe Weather

Categorical Day1 1300Z Outlook
Day 1 Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
HIGH 52,325 4,828,034 Jacksonville, FL…Tallahassee, FL…

Savannah, GA…Gainesville, FL…

Albany, GA…

MODERATE 44,236 9,345,964 Tampa, FL…St. Petersburg, FL…

Columbia, SC…Clearwater, FL…

Charleston, SC…

ENHANCED 54,540 8,455,690 Orlando, FL…Columbus, GA…

Cape Coral, FL…Fayetteville, NC…

Port St. Lucie, FL…

SLIGHT 68,779 19,272,935 Charlotte, NC…Atlanta, GA…

Miami, FL…Raleigh, NC…

Greensboro, NC…

MARGINAL 58,080 13,692,306  

Virginia Beach, VA….

Norfolk, VA…

 

 

 

 

 

 

 

 

 

A strengthening mid and upper level trough currently over Texas and Oklahoma will shift eastward into Mississippi and Alabama by this afternoon with a cold front surging east from Louisiana and Mississippi.    This storm will deepen and move north-northeastward across Alabama and Georgia.  Dewpoints ahead of this cold front are already in the 65 to 70 degree range with very buoyant air present.  The net result of these factors will be the potential for a significant tornado outbreak today.

Severe Weather is currently taking place across parts of Alabama, Georgia and Florida and a Tornado Watch is in effect until 10 AM EST.  Cluster of severe storms remain from the overnight hours and the storm environment remains favorable for supercell development.  A few tornadoes are likely and they could be intense.  Damaging winds and Large hail are also possible with these storms.

Additional watches should be expected during the day today.

While the current storms across Georgia are present, the main risk does not occur until later this morning, when thunderstorm activity will begin again over Southern Alabama and the Florida panhandle.  These storms will the spread east-northeast across Florida and Georgia through the day.  Long tracked, strong tornadoes will be possible in fast moving supercells, in addition to damaging winds and large to very large hail.  The severe risk will spread northeastward into the Carolinas this evening as the system moves toward the Southern Appalachians.  Tornadic supercells could continue to occur in south Carolina and Southern North Carolina during the overnight hours.

Further South, the cold front will reach the remainder of Florida later this evening and overnight and bring the risk of severe thunderstorms and a few tornadoes.

Any and all preparations for this event should be concluded by early this afternoon.   This will be a very dangerous situation for many people.   Please be prepared and ready at a moments notice.   We here at Firsthand Weather will do our best to be with you every step of the way this afternoon but keep your weather radios handy and pay attention to your local news broadcasts for updates on warnings that occur.    Facebook likes to prevent you from seeing our page if we post a lot of posts, as we likely will this afternoon.   To see what we are writing, you will need to go directly to our facebook pages and website, please do not count on your newsfeed to give you our information.

 

Robert Millette