NWS UPDATE: Thunderstorms Tonight - Severe Weather Threat

From: National Weather Service, Fort Worth
Date: Saturday, 21 October 2017 10:22 CDT

Bottom Line

Thunderstorms are expected to develop along and ahead of a cold front late this evening and move across North Texas through the overnight hours. Some severe weather can be expected including damaging winds and possibly a few tornadoes.

Overview

A strong storm system and associated cold front is approaching the region and will move through North Texas late tonight. Today...North Texas will remain strongly capped and thunderstorm development is generally not expected. The atmosphere is unstable and we will monitor for any breaks in the cap. More widespread thunderstorms should develop this evening well west of the area near the intersection of the cold front and dryline in the vicinity of the Wichita Falls area. This should occur around 7 pm. Thunderstorms will increase in coverage and spread south through the nighttime hours with a well defined squall line in progress in the 10pm to Midnight timeframe. Thunderstorms will continue to move across North Texas through the overnight hours, clearing the area early Sunday morning. Severe weather will be possible through the overnight hours. Damaging winds are the main threat with squall lines, however, there will be a threat for embedded tornadoes within the line of storms. These tornadoes are usually fast moving and difficult to see. In addition, they usually develop rather quickly with little advanced warning. Any storms that develop ahead of the main line of storms would be capable of producing large hail as well. Heavy rainfall is expected with the main line of storms, but the entire system is expected to move quickly. Localized flash flooding would be the main threat.

Areas of Concern/Timing
The whole area has a risk of severe weather, but the greatest chances exist north of the I-20 corridor (inside the red dashed line)

Approximate Radar Presentation between 7-9 pm

Slide1

Approximate Radar Presentation around Midnight

Slide4

Approximate Radar Presentation around 4 am

Slide8

Threats/Hazardous Weather Types

Threats

Expected Timing

Timing

Forecast Confidence

Confidence

Alternate Possibilities

What we are certain of:

  • A cold front will move through the region tonight bringing showers and thunderstorms.
  • Some severe weather is expected.
  • The highest risk of severe weather will be north of I-20 where the best combination of wind shear and instability will exist.
  • The main window for severe weather will be Saturday evening into the overnight hours.

What we are less certain of:

  • Coverage of thunderstorms ahead of main squall line. These would have a higher potential to become severe.
  • The heavy rain potential. While heavy rain is possible with these storms, it is falling on dry soils which may mitigate any flash flood risk.

FAQ

Is rain guaranteed?
Most will see rain, but it's not guaranteed for locations farther south and west toward Central Texas.

Is severe weather guaranteed?
Yes there will be at least a few severe weather reports in our 46 county area of responsibility.

How big will the hail be?
Hail up to golf ball size is possible.

Will there be tornadoes?
Isolated tornadoes are possible, especially with any cells that develop out ahead of the main line of storms on the front. Tornadoes will also be possible within the main line of storms.

When will the next email update be sent?
This is the last email for this event.

If you have any questions, please feel free to contact us through the usual means
Twitter: @NWSFortWorth
Facebook: NWSDallasFortWorth

Logo

Resources

National Weather Service Fort Worth Homepage

Hourly Forecasts (Click your location)

National Weather Service Enhanced Decision Support Page (Experimental)

National Weather Service Fort Worth Hazard Pages

--
Jason Dunn - Meteorologist
National Weather Service
Fort Worth, TX