| Show Notes from WeatherBrains 848: Joint Class | Chance Hayes, Warning Coordination Meteorologist from NWS Wichita joined us and gave a great lesson on how to be a weather spotter! We also had a discussion about the April 15 tornado emergency in Arkansas! KAIT-8 Meteorologist Ryan Vaughan talked about how things unfolded with the storms that night. We also began a needed discussion on tornado emergencies: What are they? When are they issued? And more! ▪ Increasing QLCS tornadoes in the Plains (15:05)
▪ Should there be more stringent guidelines or certifications for storm spotters? (24:00)
▪ Anatomy of supercells (47:30)
▪ Misperceptions with tornado alley (1:15:00)
▪ The Astronomy Outlook with Tony Rice (01:17:18)
▪ This Week in Tornado History With Jen (01:19:32)
▪ National Weather Round-Up
▪ E-Mail Segment (No segment this week)
| ▪ | Increasing QLCS tornadoes in the Plains (15:05) | | ▪ | Should there be more stringent guidelines or certifications for storm spotters? (24:00) | | ▪ | Anatomy of supercells (47:30) | | ▪ | Misperceptions with tornado alley (1:15:00) | | ▪ | The Astronomy Outlook with Tony Rice (01:17:18) | | ▪ | This Week in Tornado History With Jen (01:19:32) | | ▪ | National Weather Round-Up | | ▪ | E-Mail Segment (No segment this week) | Check out the show here or on your favorite podcast app! | | Coming Up on Episode 849 Monday, April 25, 2022 at 8pm ET / 7pm CT | We continue the discussion on tornado emergencies and the entire warning process! | | From the WeatherBrains Archives | | This Week's Brainy Article from James Aydelott | After Episode 846 about the March 30th Springdale Tornado, friend of the show James Aydelott sent us some of his thoughts on the event. He has put together some great explanations of some of the radar data in this week's article. If you missed our show with Dan Skoff and Mike Susko of KNWA-TV, check it out here! And here is James' Guest Article Entitled: I hate QLCS tornadoes. Hate with the burning fury of a thousand suns. | 1) That was some NASTY Non-Uniform Beam filling (NUBF) in the dual pol products. Non-Uniform Beam Filling occurs when a mixture of precip types occurs in the radar signal. It shows up as spokes of low correlation coefficient along the radar azimuth. The radar location (KSRX, Fort Smith radar) is in the worst spot to have that spoke of NUBF data be an issue with a north to south storms directly north of the radar. There are several high reflectivity cores that develop or are ongoing in the line which are causing the NUBM. |  Non-Uniform Beam Filling Spokes | | One of these cores, depicted in the reflectivity data shown, had some rotation in it too as it reoriented NW/SE, just a few miles northeast of the tornadic circulation. The tornado itself appears to have formed just southwest of that NW/SE core, w/ the rotation increasing rapidly during the 09:01:07 volume scan from KSRX (Fort Smith radar). To further complicate things: just as the Tornado Debris Signature (TDS) is in the "unloading the debris" phase as the tornado lifts and the storm unloads the lofted debris (spreading out of the TDS), another core just north of Fort Smith throws another spoke of NUBF right through the TDS!!! |  NUBF spoke through the TDS! | | 2) The Tornado Debris Signature (TDS) appears on the KSRX 0.5° (lowest) elevation CC data at 09:08:01 product time. [verify as a valid TDS by noticing the TDS is in the same spot as the center of rotation (seen on velocity data) and where reflectivity >30dbz], right on I-540. Storm survey says start time was 09:04z, so that checks out. |  KSRX radar view 4:08:01 volume start time. Upper left: Reflectivity, Upper Right: Storm Relative Velocity, Lower left: Correlation Coefficient, Lower right: Normalized Rotation. | | 3) KSRX (Fort Smith radar) is in a terrible location for detecting rear-inflow jet (RIJ) which is often perpendicular to the line. Doppler velocities only read the true maximum values when wind moves directly toward or away from the radar. But, even from KINX (Tulsa) radar, perfectly aligned to view a perpendicular rear inflow jet, I don't see much evidence of a localized RIJ surge in higher tilts either, and KINX should've been oriented perfectly for RIJ detection. | 4) Maddeningly, the magnitude of the rotation decreases on KSRX 0.5° (lowest) elevation storm relative velocity as the tornado touches down!!! |  Time series of Storm Relative Velocity data from KSRX (storm motion used: 227° 33kts) | | 5) At 09:14:30 (vertical slice image of dual pol data – correlation coefficient), the debris was being lofted to around 15,000 feet. (Entremont & Lamb, 2015 paper shows that's high end for QLCS tornadoes, and even when supercell-spawned tornadoes, debris loft to that height correlates well for EF2 or EF3 strength. |  Left: Vertical slice of CC, showing debris loft, Right: KSRX 0.5° elevation Correlation Coefficient | | Clues, in chronological order. 08:40:54 KSRX volume start time. Take a look at echo tops. The highest ET was the part of the line segment which produced the tornado. This is a differentiater makes me really focus on this part of the line. It points to this segment as having the most vigorous updraft. |  KSRX, Left: Reflectivity, Right: Echo Tops | | 08:59:30 KSRX product time on the 0.5° (lowest) elevation. Normalized rotation (NROT) spiked to 1.5. This is the circulation the tornado developed from. |  KSRX Normalized rotation | | 09:01:24 KSRX product time 0.5° (lowest) elevation. An area of increased Spectrum Width appears near Underwood Park with an area of increased rotation (seen on NROT data). Right on the west edge of a NUBF spoke. The other areas of NROT>1.0 were in the NUBF spoke of bad data. I've seen spectrum width increases with QLCS tornadoes before, usually co-located with the rotation which produces the tornado. It's not a sure fire thing, but it's a clue. (into the radar geek weeds here: Spectrum Width is Doppler data that measures the consistency of velocity phase shifts from radar pulse to radar pulse, think of it as a reliability check-something chaotic is happening in this spot, causing that higher spectrum width, I'm not smart enough to know what.) |  KSRX, Upper left: reflectivity, Upper Right: Spectrum Width, Lower Left: correlation coefficient, Lower Right: Normalized rotation | | The 0-3km shear was >40 on forecast soundings on the Oklahoma side of the state line, and the environmental winds were really strong, and that's always alarming to me in these deep convection scenarios. Weak winds and weak shear rarely spin up significant tornadoes. Overall, this was a tough one. The non uniform beam filling spokes are a giant distraction. There was no obvious localized rear-inflow jet evident on radar feeding west to east into the QLCS from KINX (Tulsa radar) or KSRX (Fort Smith radar) looking at velocity data. The hodographs and surface wind were strongly supportive of QLCS tornadoes. Lastly, there was a sharp reflectivity gradient on the leading edge of the convection, implying fairly unmodified unstable surface air was feeding the storm segment's updraft. | | Astronomy Outlook from Tony Rice | The Lyrid meteor shower peaks this week as the Earth passes through debris left behind by comet 1861 G1 Thatcher. The best time to see meteors is around midnight local time, Friday April 22 into Saturday April 23, before moonrise around 2 am. Under dark rural skies you may see 15-20 meteors per hour, half that under suburban skies. Occasional outbursts of activity, an increase in the number of visible meteors, occur. This happened in 1803, 1922, and last happened in 1982, so researchers aren't hopeful that another outburst might occur again until the 2040's. Predicting when an outburst might occur is difficult. Each year, Earth might pass through a different trail left behind by comet Thatcher. But the gravitational pull of the planets pull on this debris throughout the year in ways that are hard to predict. Researchers think that outburst might be the result of trails merging, if just temporarily. While this is not expected this year, the Lyrids are worth taking a look at, if just because you don't have to get up before dawn and can enjoy the night sky under mild spring skies. | | This Week In Weather History - Courtesy of Bill Murray | April 21
1927: Much of the Mississippi River Delta was underwater as the Great Mississippi River flood of 1927 was well underway. | April 22
1883: Very poorly documented tornado outbreak across Mississippi on the 22nd and Georgia on the 23rd killed at least 109 people. Several long track killer tornadoes occurred. | April 23
1927: Flood waters in the Mississippi Delta region of Mississippi covered an area 50 miles wide and 100 miles long to a depth or up to 20 feet! | April 24
1999: Humorous storm report from Grants AR transmitted by NWS: THUNDERING SO LOUD...PICTURES FELL OFF WALL IN SHERIFF'S OFFICE. HEAVY RAIN ALSO. | April 25
1910: Birmingham AL recorded its latest snow ever. An inch of snow was reported in Lamar County, which killed the young cron crop. | April 26
1991: Famous Andover KS tornado tracked 70 mile path, killing 17 people and destroying part of McConnell AFB. | April 27
1942: The town of war boomtown of Pryor, OK was nearly destroyed by an especially violent tornado that struck at 4:45 p.m. Central War Time. 52 people died in the disaster, making it the fifth deadliest tornado in the history of the Sooner state. | | Upcoming Guest WeatherBrains | May 2...Ryan Hall Y'all May 9...Eric Sorenson May 16...History of the Monthly Weather Review May 23...Dennis Feltgen Retirement Party | | | |
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