Weather Blog: Sunday PM UPDATE – Severe Weather Possible Overnight Tonight

Weather Blog

NORTHWEST ARKANSAS/RIVER VALLEY, Ark (KNWA/KFTA) –

Sunday, October 10 5:00 PM Update

Updated Severe Weather Outlook

An enhanced risk (level 3/5) has been issued for parts of Oklahoma and western Arkansas. These areas are indicated by the orange polygon. The rest of our area is under a slight risk (level 2/5). This means ingredients are less favorable in these areas compared to the region under the enhanced risk. However, severe storms will still be possible across the entire region during this event. The moderate risk (level 4/5) remains west of our area in Oklahoma.

Day 1 Convective Outlook from the Storm Prediction Center as of 5 P.M. Sunday, October 11, 2021.

All threats will be on the table as storms roll through the region Sunday night. This includes heavy rain leading to localized flash flooding, frequent lightning, damaging straight-line wind gusts, large hail, and a few isolated tornadoes.

Severe weather risk for overnight Sunday, October 10. Updated: 5 P.M. October 10, 2021.

Timing

Storms are starting to develop in western and central Oklahoma before pushing eastward into eastern Oklahoma and Arkansas later tonight. The best chance for storms in far eastern Oklahoma will be right around 11 PM Sunday. Storms will then enter NW Arkansas after midnight and the River Valley a little bit later.

HRRR forecast model as of 5 P.M. CDT October 10, 2021.

The most likely timing for severe weather in our area will be 11 P.M. Sunday – 6 A.M. Monday. Since this is an overnight event, you will need to make sure you have a way to receive weather alerts and they will wake you up! Severe weather is most dangerous at night because most people are asleep.

Expected storm timing for NW Arkansas and the River Valley.

It is recommended you have a MINIMUM of 3 different ways to receive alerts. This can include (but is not limited to) the NWA Weather Authority app, local county emergency alert services (CodeRED in Washington County or Benton County Alert (BC Alert), etc), trusted social media sources, wireless emergency alerts (WEA alerts), local news stations, and NOAA weather radios.

Image provided by National Weather Service Tulsa, OK office

While the event is getting closer, some changes to the forecast are still possible. Keep it here with your Weather Authority for the latest information.

Weather Safety & Education Links

Want to learn more about severe weather and what to do when it is threatening your area? Check out our weather 101 and weather blog links below.

Tornado Content

Severe Thunderstorm Content

Flash Flooding Content

Sunday, October 10 8:20 AM Update

Updated Severe Weather Outlook

An enhanced risk (level 3/5) has been issued for parts of Oklahoma and western Arkansas. These areas are indicated by the orange polygon. The rest of our area is under a slight risk (level 2/5). This means ingredients are less favorable in these areas compared to the region under the enhanced risk. However, severe storms will still be possible across the entire region during this event. The moderate risk (level 4/5) remains west of our area in Oklahoma.

Day 1 Convective Outlook from the Storm Prediction Center as of 8 A.M. Sunday, October 11, 2021.

All threats will be on the table as storms roll through the region Sunday night. This includes heavy rain leading to localized flash flooding, frequent lightning, damaging straight-line wind gusts, large hail, and a few isolated tornadoes.

Timing

Storms will develop first in Oklahoma Sunday afternoon and evening before pushing eastward into Arkansas. The best chance for storms in far eastern Oklahoma will be right before or at midnight Monday morning. Storms will then enter NW Arkansas after midnight and the River Valley a little bit later.

The greatest risk for severe weather will be along the initial line that moves across the region. There will be some residual showers and thunderstorms behind this line for the Monday morning commute in our area, but these will not be severe. So, the most likely timing for severe weather in our area will be midnight -around 5 A.M. CDT Monday. Keep in mind, timing may change slightly as we get closer to the event. Since this is an overnight event, you will need to make sure you have a way to receive weather alerts and they will wake you up! Severe weather is most dangerous at night because most people are asleep.

It is recommended you have a MINIMUM of 3 different ways to receive alerts. This can include (but is not limited to) the NWA Weather Authority app, local county emergency alert services (CodeRED in Washington County or Benton County Alert (BC Alert), etc), trusted social media sources, wireless emergency alerts (WEA alerts), local news stations, and NOAA weather radios.

Image provided by National Weather Service Tulsa, OK office

While the event is getting closer, some changes to the forecast are still possible. Keep it here with your Weather Authority for the latest information.

Weather Safety & Education Links

Want to learn more about severe weather and what to do when it is threatening your area? Check out our weather 101 and weather blog links below.

Tornado Content

Severe Thunderstorm Content

Flash Flooding Content


Saturday, October 9 8:30 PM Update

Severe storms are expected across Northwest Arkansas and the River Valley overnight Sunday into Monday morning. Here is a look at the latest forecast information

Severe Weather Risk

An enhanced risk (level 3/5) has been issued for parts of Oklahoma, including sections of western Sequoyah and Le Flore counties. Western Arkansas and the rest of eastern Oklahoma are under a slight risk (2/5) for severe storms.

Day 2 Convective Outlook from the Storm Prediction Center. Updated: 7:45 PM CDT October 9, 2021.

All threats will be on the table as storms roll through the region Sunday night. This includes heavy rain leading to localized flash flooding, frequent lightning, damaging straight-line wind gusts, large hail, and a few isolated tornadoes.

Individual severe weather threats from the Storm Prediction Center for overnight Sunday, October 10. Updated: 7:45 PM CDT October 9, 2021.

Timing

Storms will develop first in Oklahoma Sunday afternoon and evening before pushing eastward into Arkansas. The best chance for storms in far eastern Oklahoma will be right before or at midnight Monday morning. Storms will then enter NW Arkansas after midnight and the River Valley a little bit later.

The greatest risk for severe weather will be along the initial line that moves across the region. There will be some residual showers and thunderstorms behind this line for the Monday morning commute in our area, but these will not be severe. So, the most likely timing for severe weather in our area will be midnight -around 4 A.M. CDT Monday. Keep in mind, timing may change slightly as we get closer to the event. Since this is an overnight event, you will need to make sure you have a way to receive weather alerts and they will wake you up! Severe weather is most dangerous at night because most people are asleep.

GRAF model displaying radar and satellite for Sunday, October 10, and Monday, October 11. Update: 8 PM October 9, 2021.

It is recommended you have a MINIMUM of 3 different ways to receive alerts. This can include (but is not limited to) the NWA Weather Authority app, local county emergency alert services (CodeRED in Washington County or Benton County Alert (BC Alert), etc), trusted social media sources, wireless emergency alerts (WEA alerts), local news stations, and NOAA weather radios.

While the event is getting closer, some changes to the forecast are still possible. Keep it here with your Weather Authority for the latest information.

Weather Safety & Education Links

Want to learn more about severe weather and what to do when it is threatening your area? Check out our weather 101 and weather blog links below.

Tornado Content

Severe Thunderstorm Content

Flash Flooding Content


Friday Evening Update

A very strong weather system for this time of the year looks to impact our area for the start of the workweek. Thunderstorms arrive sometime after midnight Sunday through the Monday morning rush hour. Here’s what you need to know to prepare for this system.

After a near-record hot and breezy weekend, a cold front will move into the region Monday morning driven by a developing surface low that tracks from west Texas to eastern Kansas. Thunderstorms will be likely and with the severe weather ingredients in place, some of these storms will likely pack a punch. The storms are expected to develop initially over central Oklahoma by late Sunday evening then move into western Arkansas well after midnight and possibly around sunrise Monday.

Expected surface map across the area Monday morning. Updated: October 8 at 4:30 P.M. CDT

Here is what the latest European (ECMWF) and American (GFS) model is forecasting by Monday morning. You will notice the GFS is slightly quicker with the system, which is a known bias for the GFS being too fast with systems moving through.

Low pressure at the surface will be located near Wichita, moving toward Kansas City early Monday morning. With the low tracking to our northwest, strong southerly winds will pull moisture from the Gulf of Mexico into our region. Scattered to numerous showers and thunderstorms will become likely ahead of the front late Sunday night, with the mainline of severe storms moving in probably well after midnight.

Here is a look at the Jet Stream pattern produced by the same models:

The Jet Stream forecast by the same European model indicates what we call a “Negatively-Tilted Trough” moving across western Kansas. A negative tilt indicates an angle from northwest to southeast. This type of jet stream pattern creates a lot of instability and lift for thunderstorms, really agitating the atmosphere ahead of the trough. Notice the GFS shows a similar setup, but once again is slightly faster.

Above is the Day 3 Severe Thunderstorm Outlook for Sunday late afternoon into Monday morning from the Storm Prediction Center. Most of us are now included in a slight risk for severe thunderstorms, but Fort Smith and southwest of there are included in a level three enhanced risk. The most intense storms will be located where they first develop over central Oklahoma.

As the storms move east, it looks like they will become a line of storms as they arrive into western Arkansas. A line of storms favors strong and gusty thunderstorm wind. That forecast could certainly change over the next couple of days so check back in over the weekend for later updates.

Timing of the storm system’s arrival is still expected in the early morning hours of Monday and possibly during the morning rush hour.

We are still a few days out and obviously, this forecast will run through some changes. But we don’t want ANYONE to be surprised by the stormy start to your work week after such a warm and uneventful weekend. Keep it here with your Weather Authority for the latest information.

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