AMS Severe Local Storms STAC

We're continuing to highlight our student committee members! Meet Bobby Saba:

We're highlighting the student members of our committee! Up this week is Kristen Axon:

Congratulations to Richard Thompson on receiving the 2025 AMS SLS STAC award! Rich is the Director of Forecast Operations at the Storm Prediction Center in Norman, OK. He received the award for conducting exceptional applied research to advance severe thunderstorm and tornado forecasting.

Current membership of the SLS committee. We'll be highlighting the work of our student members over the coming weeks!

Houser: very high-res simulated tornado paths affected by terrain, not by land cover; adding idealized or realistic terrain results in stronger tornadoes at some point in life cycle; roughness modulates height of max winds #AMS21Meso

Berman: overshooting top area is most closely related to environmental shear (via updraft core area), while overshooting top depth is mostly determined by upper troposphere/lower stratosphere static stability #AMS21Meso

Fu: simulations addressing complications to RKW framework when low-level jets interact with cold pools; faster LLJ and lower LLJ altitude associated with stronger convective systems #AMS21Meso

Starting off with more storms this morning at #AMS21Meso 🧵

Rasmussen: both pseudo-global warming and downscaling approaches find decreased weak convection and increased strong convection in a future climate, associated with larger CAPE and larger CIN over central and eastern CONUS

Faletti: EnKF WoFS-TORUS analyses of 2022 Morton, TX tornadic supercell; accurate representation of complex supercell evolution, including cyclic low-level mesocyclones; tradeoffs for reflectivity assimilation #AMS21Meso

De Bruin: UAS + mesonet + radar analysis of supercell left flanks during TORUS. Both density current and convergent boundary structures found; vortex sheets located just behind surges and strongest at sfc; horizontal w gradients at boundaries contribute to streamwise vorticity #AMS21Meso

Davis: observed cold pool structures, including wind perturbations, vary with convective intensity/organization; cold pool motions closely correlated with predicted density current motions #AMS21Meso

#AMS21Meso storm topics this afternoon 🧵

Mullendore: Lower entrainment in observed updrafts for high shear, high LCLs, high ECAPE, low midlevel RH, and low MUCAPE; first such analysis for midlatitude continental storms

Back at it with storms this morning at #AMS21Meso 🧵

Lane: Stratiform orientation and system tilt in Australian linear convection determined by MUCAPE and deeper layers of shear, rather than 0-3-km shear or possible cold pool strength

Schwartz: results from medium-range MPAS convection-allowing ensembles; benefits of CAM resolution greater in weakly forced regimes (like spring 2023) vs. strongly forced (like spring 2024) #21Meso

Garcia: synoptic patterns of tor/nontor RM supercells via self-organizing maps of midlevel height fields; high-amplitude troughs = higher tornado probability, and faster jets = higher conditional % significant tornadoes #21Meso

More storms topics from the #21Meso afternoon sessions... 🧵

Marinescu: among fields important for convective storms, CAPE, near-surface winds, and mid-tropospheric moisture are most variable, and temperature and upper-level winds are least variable

Britt: QLCS tornado prediction in WoFS with QTor product: 0-3-km line-normal shear, 0-1-km line-parallel shear, and a factor representing local tortuosity of the QLCS #21Meso

McDaniel: applying a U-net to radar data for QLCS tornado prediction; using probability-matched means to assess input skill; evaluating single- vs. dual-pol inputs #21Meso

Brown: three-ingredients method for QLCS tornado forecasting should reduce its line-normal shear threshold and account for low-level line-parallel shear; regimes of cyclonic-only vs. mixed cyclonic/anticyclonic mesovortices by shear types #21Meso

Peters: squall lines less efficient at converting buoyancy to upward acceleration than isolated updrafts; increasing updraft tilt makes them even less efficient; peak intensity/minimum dilution when cold pool/shear balance is near 1 #21Meso

Yang: n=2 gravity waves ahead of simulated MCSs initiate new convection downstream, with feedback effect on intensity #21Meso

Wade: derecho vs. non-derecho MCS environments in the US; deeper layers of shear, like 1-9-km AGL, appear most useful #21Meso

Plenty of severe storms topics this week at the 21st Conference on Mesoscale Processes in Boise 🧵

#31SLS is underway in Ballroom D/E with an opening session on perception and risk associated with severe weather!

Students: #SLS31 is your conference! In addition to everything else going on, check out these student-oriented activities! Come get some ice cream after you settle in, network at a Student and Early-Career Reception, and hang out at a student coffee break. We look forward to seeing you there!

Calling all students and early careers at #SLS31! Before the big Icebreaker Reception at 7p on Monday evening, come network at a Student/Early-Career Reception starting at 6p! Appetizers, cash bar, and great conversations will be available.

🎬 🎬 Want to watch some amazing storm videos at #SLS31? Come check out Video Night on Thursday evening (7:30–10p) in Salon DE!

Resuming our #31SLS special conference event highlights - we are happy to share that AMS Coriolis has organized a Queer Gatherings coffee for Monday, Oct 21 at 4:15 PM ET! 🏳️‍🌈 Feel free to DM @chasinjason.bsky.social with any questions!

Friendly reminder to please consider applying for the SLS STAC! Applications are due by THIS FRIDAY, October 18th. Please check out some tips for writing your statement of interest here: docs.google.com/document/d/1...

We are HYPED for the #31SLS Women's Dinner!