Strong Tornadoes Likely Across South

Strong tornadoes are likely today into tonight for parts of the South extending northward into Tennessee and southern parts of Kentucky. This will be the first severe thunderstorm and tornado outbreak of the year, which is why the Storm Prediction Center has issued its first moderate risk of the year (see Fig. 1). The moderate risk extends from south-central Tennessee into northern & central Mississippi and northwestern Alabama. Surrounding the moderate risk is an enhanced risk which extends from southern Kentucky southward into northeastern Louisiana.

Fig. 1: Thunderstorm outlook for Saturday (from the SPC)

A strong, negatively tilted shortwave trough is advancing eastward this morning from the Southern Plains. With this trough is a strong jet aloft. Ahead of the trough and jet, across the South, 60 & 70 degree dewpoints have already surged northward due to a strong surface low that is deepening in the Plains (this low is responsible for the blizzard conditions from the Texas Panhandle into Iowa). This will set the stage for very intense, rotating updrafts this afternoon. At this hour (this morning), intense thunderstorms have already developed across western Arkansas extending southward into northwestern Louisiana and eastern Texas. These storms will race eastward into the Mississippi Delta by this afternoon. At that point, all the atmospheric conditions will be primed for strong tornadoes. Along with strong tornadoes (see Fig. 2), large hail (see Fig. 3) and damaging winds (see Fig. 4) are possible. Other hazards are lightning and flash flooding.

Fig. 2: Tornado probabilities for Saturday (from SPC)
Fig. 3: Hail probabilities for Saturday (from SPC)
Fig. 4: Damaging wind probabilities for Saturday (from SPC)

Here is a snapshot of what the radar may look like early this afternoon (see Fig. 5) and by early evening (see Fig. 6). Notice the primary broken line of thunderstorms along with the isolated storms ahead of this line. It is possible tornadoes may exist in the line of thunderstorms with discreet supercells (producing tornadoes) out ahead of the main line.

Fig. 5: Simulated radar early Saturday afternoon
Fig. 6: Simulated radar early Saturday evening

Make sure you are weather-alert today & tonight. Have a plan in place in case a warning is issued for your area!

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


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

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.


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.


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.


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


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, 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.


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.


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.




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.



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 for Southeast, fires continue

Severe Weather will come with rain as drought conditions are still going strong despite the recent rains.  It cannot be emphasized enough that the fires that saw 3 lives end in Tennessee can still continue over the coming days.    Arson investigations have been opened in some of these fires as investigators begin to determine how the fires started but fire conditions will not take long to return to areas once the rains pass so please remain vigilant in your daily activities when fire is involved.  To all of our readers and their neighbors in these regions,  stay safe and plan ahead.   As seen in Gaitlinburg, these fires can come very quickly.  Prepare in advance and be ready to leave at a moments notice with multiple escape routes as options.


Rain will continue in the southeast tonight into Wednesday from Extreme Eastern Texas over the South Florida along the gulf up north through Arkansas into the Ohio Valley and Great Lakes regions.  Additional precipitation is possible in New England with freezing rain advisories issued for the higher and more northern elevations.  Severe Weather, including Flash Floods and Tornadoes are possible tonight and will be addressed in this post.

A slowly weakening low pressure system across the northern plains and Upper Midwest will continue to bring potentially heavy snow to the Dakotas into this evening, before snow begins to gradually taper off overnight. Scattered snow and some rain showers will still be possible across the northern plains and Upper Midwest into Wednesday.

Farther east, widespread rain and even some thunderstorms are expected tonight and Wednesday from the lower Mississippi valley to the Northeast. Some areas of heavy rain are possible across portions of the lower Mississippi and Tennessee valleys through tonight as some significant rains have already fallen in the area.


The showers and thunderstorms will reach the East Coast on Wednesday, with thunderstorms possible from the Southeast to the southern Mid-Atlantic region. By late in the day, snow is expected to develop across northern Maine as the precipitation spreads into colder air already in place. Snow may be heavy
at times Wednesday night into Thursday.


Strong low pressure seen here moving into Canada has dragged a cold front south draped down into the Carolinas.  This weakening front brought the region last nights rain.  A second cold front associated with this low is now moving through Illinois down into Texas.  This front, along with a developing warm front moving north from the gulf are what will set the stage for tonight’s Severe Weather risk

Severe Weather Returns

severe weather

Day 1 Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
MODERATE 13,427 585,227 Tupelo, MS…Starkville, MS…Greenwood, MS…Grenada, MS…Oxford, MS…
ENHANCED 42,707 2,601,397 Baton Rouge, LA…Jackson, MS…Monroe, LA…Greenville, MS…Florence, AL…
SLIGHT 113,393 11,559,771 Nashville, TN…New Orleans, LA…Birmingham, AL…Mobile, AL…Huntsville, AL…
MARGINAL 49,543 6,567,755 Memphis, TN…Lexington-Fayette, KY…Montgomery, AL…Knoxville, TN…Beaumont, TX…

The storm prediction center has upgraded a small region in Northern Mississippi to a moderate risk while large portions of the south east remain in an enhanced or slight risk area.  The  risk for Tornadoes is large tonight and Tornado watches have already been issued for several counties.


Day 1 Tornado Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
SIG SEVERE 56,076 3,179,960 Baton Rouge, LA…Jackson, MS…Monroe, LA…Greenville, MS…Tupelo, MS…
15 % 13,456 588,577 Tupelo, MS…Starkville, MS…Greenwood, MS…Grenada, MS…Oxford, MS…
10 % 42,678 2,598,047 Baton Rouge, LA…Jackson, MS…Monroe, LA…Greenville, MS…Florence, AL…
5 % 70,735 7,846,202 Nashville, TN…New Orleans, LA…Birmingham, AL…Huntsville, AL…Metairie, LA…
2 % 43,513 4,379,865 Chattanooga, TN…Clarksville, TN…Beaumont, TX…Gulfport, MS…Lake Charles, LA…

The risk for significant tornadoes exists from Baton Rouge and Monroe Louisiana north towards Florence Alabama and just south of Nashville Tennessee, however, tornadoes can be expected from Beaumont Texas right up into Central Kentucky.

Current Tornado Watches

tor-watch-1 tor-watch-2

These watches extend from near Alexandria Louisiana to almost Jackson Tennessee and include Monroe Louisiana and Jackson and Tupelo Mississippi.  Memphis Tennessee remains just north east of the watch area but Tornadoes can occur outside the watch boxes so vigilance must be maintained.

The latest radar imagery show several strong and locally severe storms ongoing across the Lower Mississippi Valley area.  Advection will continue to occur across the Central Gulf Coast States and move into the Tennessee Valley as an upper level system approaches.  The Severe Weather and Tornado risk will spread northward with time.

firsthand Weather expects that Tornado Watches will continue to be expanded northeastward into further into Tennessee as scattered supercells in Mississippi move in that direction this evening.  Northeast Alabama and Tennessee should begin to see the impacts of these storms this evening into the overnight.  The environment is becoming more favorable for rotating storms as the evening goes on, especially in Northeast Mississippi.  Large hail and damaging winds will also be a risk tonight.



Robert Millette

Firsthand Weather



Hermine continues to slam the East Coast

Hermine, still a tropical storm, is moving toward the northeast near 22 mph, and this general motion is expected to continue with some decrease in forward speed through Saturday night. A gradual turn toward the north is expected on Sunday.  On the forecast track, the center of Hermine will continue to move across eastern North Carolina during the next several hours and emerge over the Atlantic later today.  Maximum sustained winds remain near 60 mph with higher gusts.  Strengthening is forecast after the center moves over water, and Hermine could be near hurricane intensity by Sunday.  Tropical storm force winds extend outward up to 185 miles mainly to the south and east of the center.   The estimated minimum central pressure is 997 mb.Hermine



A Tropical Storm Warning is in effect for…

Surf City, North Carolina to Sandy Hook, New Jersey, including Pamlico and Albemarle Sounds, Chesapeake Bay from Drum Point southward, the Tidal Potomac from Cobb Island eastward and  Delaware Bay

A Tropical Storm Watch is in effect for…

North of Sandy Hook, New Jersey to west of Watch Hill, Rhode Island, including Long Island.


Tropical storm conditions will continue to spread northward within the warning area along the Atlantic coast through Sunday.  Tropical storm conditions are possible in the watch area by
late Sunday or Sunday night.   The combination of a storm surge and the tide will cause normally dry areas near the coast to be flooded by rising waters moving inland from the shoreline.  There is a danger of life-threatening inundation during the next 24 hours in the Hampton Roads area as a storm surge of 3-5 feet comes ashore.  Persons within this area should take all necessary
actions to protect life and property from rising water.  There is also the possibility of life-threatening inundation during the next 48 hours at most coastal locations between the North Carolina/Virginia border and Bridgeport, Connecticut as storm tides of 2-4 feet come ashore.  These tides will combine with expected rainfall accumulations of 4-7 inches from Southeastern Virginia and Atlantic Coastal Maryland and may contribute to additional flooding.

Storm surge Hampton Roads storm surge New york Philly New England

Hermine is beginning to undergo an extra tropical transition, but once back over open waters, may redevelop her tropical characteristics and should approach Hurricane Strength off the Delmarva while south of New England.   Areas north of Virginia under a Tropical Storm Warning or Watch should prepare for conditions to worsen throughout the weekend, as should coastal areas of Massachusetts and Rhode Island.

Severe weather risk for the Upper Midwest

Severe weather is currently active over the Northern Plains with a tornado watch and multiple severe thunderstorm watches active this evening.


A potent shortwave trough is moving across the Northern Plains this afternoon and is expected to move towards the Upper Mississippi Valley by Friday.  Currently, the greatest threat for severe weather exists from the  Black Hill region of the Dakotas East and Southeast across the Mid-Missouri Valley.  Strong and damaging wind gusts, very large hail and a few tornadoes are expected.   Multiple Mesoscale Convective systems from these severe storms will continue to progress further East from the Midwest down to the Carolinas  and Georgia.

severe outlook

Day 1 Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
MODERATE 35,708 282,582 Mitchell, SD…Pierre, SD…Yankton, SD…Vermillion, SD…
ENHANCED 90,604 4,130,773 Nashville, TN…Des Moines, IA…Sioux Falls, SD…Clarksville, TN…Sioux City, IA…
SLIGHT 214,768 10,921,413 Omaha, NE…Lexington-Fayette, KY…Lincoln, NE…Savannah, GA…Cedar Rapids, IA…
MARGINAL 372,120 43,514,822 Columbus, OH…Memphis, TN…Charlotte, NC…Kansas City, MO…Cleveland, OH…

Tornado Watch Active

tornado outlook


Northern Nebraska, Western South Dakota and Far Northeast Wyoming until 10 PM CDT.


A few more tornadoes are likely with a couple of intense tornadoes possible.  Currently, there is an active Tornado Warning for a tornado on the ground in cherry County Nebraska.  Widespread Large hail and isolated very large hail to 3.5 inches in diameter likely and widespread damaging winds likely with isolated gusts to 80 MPH possible.

Intense thunderstorms, including Supercells and Supercell clusters have formed over the watch area and are moving towards the Eastern portion of the watch area.  South of this watch area, the Tornado risk is much smaller and a Severe Thunderstorm Watch is in effect until 10 PM CDT.  Squall line development is expected from the storms further north in the Tornado watch area.  This squall line will move into Central and Southern Nebraska and move toward the Southeastern and Eastern portions of this watch area.

tornado outlook

Further North,   a line of storms from Montana has moved into the Dakotas.  The severe thunderstorm watch for this area is slowly being cancelled from west to East but remains in effect for the Western Dakotas until 9 PM CDT.


Severe Thunderstorm Watches are in effect for a small portion of Central Tennessee, this watch should be cancelled shortly.


Thursday Severe Risk

severe outlook

Day 2 Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
ENHANCED 120,618 9,748,278 Minneapolis, MN…Des Moines, IA…Cedar Rapids, IA…Springfield, IL…Peoria, IL…
SLIGHT 206,214 34,063,611 Chicago, IL…Indianapolis, IN…Milwaukee, WI…Omaha, NE…St. Louis, MO…
MARGINAL 347,083 42,004,487 Detroit, MI…Columbus, OH…Charlotte, NC…Nashville, TN…Kansas City, MO…

A complex setup is set for Thursday with multiple rounds of convection expected across a large region.  Clusters of severe thunderstorms will be likely within a Mesoscale Convective System over Iowa and  Southern Minnesota.  Downstream of this area, dew points  in the 70s will combine with daytime heating to form a moderately to strongly unstable air mass through the day. This set up should yield multiple clusters of intensifying storms from the late morning into the afternoon across parts of the Midwest.

In the wake of the morning activity, low level moisture should return on the Southwesterly flow underneath the elevated mixed layer.  Moderate to extreme mid-level cape could help generate another mesoscale convective system Thursday evening in the Iowa, Missouri, Illinois border area.

Farther north, strong mid-level winds associated with the trough will overspread Minnesota where strong instability already exists.  While instability does decrease the further north you go, scattered to widespread storms should form mid-afternoon to early evening.  Deep shear will be sufficient for organized strong clusters and embedded supercells.  Large hail and strong winds will be the primary risks.

Robert Millette

Staff Meteorologist

Firsthand Weather




Major severe risk across Ohio Valley

A moderate severe risk will bring widespread Damaging Wind gusts in excess of 70 miles per hour along with tornadoes and isolated large hail are expected this afternoon and evening from Northeast Iowa into extreme Southern Wisconsin, Northern Illinois, Southwest Michigan, North and Central Indiana and Western Ohio.  The wind damage threat will affect the Upper Ohio Valley Late this evening into the Central Appalachian Mountains during the overnight period. 

severe risk

Day 1 Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
MODERATE 50,489 17,159,246 Chicago, IL…Fort Wayne, IN…Aurora, IL…Dayton, OH…Rockford, IL…
ENHANCED 75,211 14,071,627 Indianapolis, IN…Columbus, OH…Pittsburgh, PA…Toledo, OH…Cincinnati, OH…
SLIGHT 114,349 25,466,262 Detroit, MI…Baltimore, MD…Milwaukee, WI…Washington, DC…Cleveland, OH…
MARGINAL 242,590 39,815,217 Philadelphia, PA…Charlotte, NC…Nashville, TN…Virginia Beach, VA…Minneapolis, MN…

A belt of stronger westerly winds will persist across the northern tier states including the Great Lakes and Ohio Valley.  There is a shortwave trough embedded within the stronger winds aloft.  This trough will move from Northern North Dakota to the Upper Great Lakes by this evening.  This trough, along with a surface low over Nebraska.  A warm front extends from this low through Southern Iowa and Southern Iowa into Southern Indiana.  This warm front will move north into Northern Illinois today as the low moves into Eastern Iowa this afternoon. 

Strong storms from this morning, which had prompted several Severe Thunderstorms this morning, shifted southeastward along the convectively enhanced warm front.  This movement was in response to a strong southwesterly low level jet stream.  As the Warm front moves north, moist low level air will bring dew points into the 70s from the Mid-Mississippi Valley to the Ohio Valley.  Storms will develop in the vicinity of and north of this warm front with supercells being the primary initial mode of storm.  Very Large Hail will be likely with the initial storms. 


Day 1 Hail Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
SIG SEVERE 25,480 10,316,848 Chicago, IL…Aurora, IL…Rockford, IL…Naperville, IL…Joliet, IL…
30 % 12,213 4,222,164 Aurora, IL…Rockford, IL…Naperville, IL…Joliet, IL…Elgin, IL…
15 % 90,996 18,409,308 Chicago, IL…Indianapolis, IN…Minneapolis, MN…St. Paul, MN…Fort Wayne, IN…
5 % 191,529 34,507,995 Detroit, MI…Columbus, OH…Milwaukee, WI…Cleveland, OH…Raleigh, NC…


There is a significant risk of Tornadoes with these storms, especially across Northeastern Iowa, Southern Wisconsin and Northern Illinois west of Chicago.  But the risk extends across the Ohio Valley into the Appalachians into the overnight hours. 

tornado outlook

Day 1 Tornado Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
SIG SEVERE 24,082 6,403,348 Aurora, IL…Rockford, IL…Naperville, IL…Joliet, IL…Elgin, IL…
10 % 41,673 13,277,336 Chicago, IL…Aurora, IL…Rockford, IL…Naperville, IL…Joliet, IL…
5 % 71,076 14,627,057 Indianapolis, IN…Columbus, OH…Milwaukee, WI…Toledo, OH…Cincinnati, OH…
2 % 105,218 19,386,926 Detroit, MI…Cleveland, OH…Pittsburgh, PA…Lexington-Fayette, KY…Akron, OH…


Storms will grow upscale into a fast moving mesoscale convective system and Derecho.  The primary threat across the Ohio Valley into the Southern Great Lakes will be strong and damaging straight line winds.  Conditions appear favorable for a swath of significant damaging winds during the late afternoon and early evening. 

severe watch

Day 1 Wind Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
SIG SEVERE 82,916 22,731,124 Chicago, IL…Indianapolis, IN…Columbus, OH…Cincinnati, OH…Fort Wayne, IN…
45 % 51,341 17,323,133 Chicago, IL…Columbus, OH…Fort Wayne, IN…Aurora, IL…Dayton, OH…
30 % 75,230 13,798,843 Indianapolis, IN…Pittsburgh, PA…Toledo, OH…Cincinnati, OH…Akron, OH…
15 % 114,507 25,961,856 Detroit, MI…Baltimore, MD…Milwaukee, WI…Washington, DC…Cleveland, OH…
5 % 241,275 39,436,728 Philadelphia, PA…Charlotte, NC…Nashville, TN…Virginia Beach, VA…Minneapolis, MN…

Robert Millette

Staff Meteorologist

Firsthand Weather

Severe Weather Update

Severe thunderstorms are expected this afternoon with the primary risk over Texas.

severe outlook

Day 1 Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
ENHANCED 20,860 199,864 Del Rio, TX…Uvalde, TX…Pleasanton, TX…Hondo, TX…
SLIGHT 39,819 3,629,577 San Antonio, TX…Laredo, TX…Mission, TX…Pharr, TX…Edinburg, TX…
MARGINAL 109,236 25,822,516 Houston, TX…Jacksonville, FL…Austin, TX…New Orleans, LA…Tampa, FL…


Clusters of strong to severe thunderstorms with large hail to locally very large hail,and locally damaging winds in excess of 60 miles per hour are expected across Southwest and South Central Texas.  There is potential for a few Tornadoes in this area.

tornado outlook

Day 1 Tornado Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
5 % 21,049 202,528 Del Rio, TX..Eagle Pass, TX..Uvalde, TX…Hondo, TX…
2 % 84,937 19,833,286 San Antonio, TX..Jacksonville, FL..New Orleans, LA..Tampa, FL…Laredo, TX…

Currently, A severe thunderstorm watch has been issued from just eats of Marfa down to Hondo and just west of Cotulla.  This watch includes Midland, Del Rio, San  Angelo and Junction Texas.

severe watch

This watch is in effect until 10  PM Central Daylight time.  Additional watches are possible East and Southeast of the current watch box.  Hail up to 2.5 inches in diameter and winds up to 70 mph are possible in this region as additional storms form when coverage increases later this afternoon.

Severe Weather Analysis


A few storms are forming over the Lower Pecos Valley and they should strengthen this afternoon along a slow moving cold front.  The air mass within this area and the Concho Valley is moderately unstable at this time with substantial wind shear.  The risk will spread downstream later this evening towards the Edwards Plateau.

The surface ridge over the Southern Plains exhibits maturing thunderstorms on the latest visible satellite imagery across Big Bend and Northern Mexico.  Strong boundary layer heating is noted in this region.  Convective temperatures will be breached later this evening West of the Rio Grande and supercell activity is expected to move east into Texas.

Robert Millette

Staff Meteorologist

Firsthand Weather