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

 

 

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

 

Severe weather to strike again in Northeast

The severe weather simply refuses to quite down in the Northeast as we move into what we expect to be our third day of severe weather in 4 days.  The past week has seen New England experience 4 Tornadoes in New Hampshire and Maine, though all were thankfully weak and In mostly uninhabited regions.

Currently, a shortwave trough moving through Ontario is expected to move into Southern Quebec by Monday.  A mid-level disturbance is moving around the bottom of this shortwave and the disturbance will induce height falls at the 500 millibar level through Monday afternoon into Monday night, increasing the overall instability of the region.  A cold front associated with the trough will move through the Great Lakes region into New England with the trailing southern portion extending through the Ohio River Valley back into Arkansas and Oklahoma.

image

Severe Summary

Southwesterly flow ahead of the trough and cold front has been working to moisten the air across Pennsylvania and New York.  This moist air is spreading into the Hudson River Valley and will expand across much of Western and Southern New England through Monday afternoon.  Dew points are expected to climb well into the 60s at the surface with some locations approaching 70 degrees.  There will be an elevated mixed layer between 700 and 500 millibars that should spread east atop this moist air which should allow for cumulonimbus clouds to build to very high heights for this area, especially across Central and Eastern New York, Northeast Pennsylvania and Western areas of New England.

There may be some limiting factors to overall destabilization if some early period convection and cloudiness occurs to limit day time heating, but moderate to high mid to upper-level cape (convective available potential energy) and strong forcing from the cold front is expected to help overcome any deficiencies that may occur from areas of limited heating.  Strengthening deep layer shear is also going to be a factor and the increasing shear conditions over New York and Northern Pennsylvania as well as Western and Central New England should bring higher severe weather risks.

Strengthening westerly winds with height suggest organized storms will be possible, with some splitting of storms occurring.  Damaging winds will be the primary threat though some hail cannot be ruled out.

 

Robert Millette

Staff Meteorologist

Firsthand Weather

 

Southern Plains Storms

As expected this time of the year, it has been hot and oppressive across the Southern Plains this week. Luckily, changes are in store beginning tomorrow (Friday). An approaching upper-level trough will push a cool front into northern Oklahoma late tonight into Friday. This cool front will provide adequate lift to generate scattered thunderstorm activity along and north of I-40 in Oklahoma, southern Kansas, and parts of the Texas Panhandle. Any thunderstorm that develops tomorrow has the chance to become severe. The main threats are damaging winds and large hail.
Slide02
SPC Thunderstorm Forecast (Friday)

Heavy rainfall is possible with the thunderstorm activity on Friday, too, and the rain chances will continue through Sunday. These rain chances will continue throughout the weekend due to a couple upper-level disturbances moving across the area. 1-2″ is possible north of I-40, and for parts of the Texas Panhandle; with isolated higher amounts.
Slide03
NAM Rainfall Forecast Through The Weekend

While most of southern Oklahoma and northern Texas wont see widespread rain chances. A few thunderstorms are possible for these areas; however, the more widespread activity will remain further north. Areas that do not see rainfall/cloud-cover can expect temperatures and humidity levels to remain uncomfortably high.

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.

Summary

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

THE NWS STORM PREDICTION CENTER HAS ISSUED A TORNADO WATCH FOR

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

 

 

 

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…

Summary

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