David Schultz: Current Research

David M. Schultz: Research Interests

CURRENT RESEARCH INTERESTS

FRONTS: My M.S. thesis was on occluded fronts. With the honor of speaking at the Fred Sanders Symposium in January 2004, I was given the opportunity to revisit many issues of frontal structure and dynamics that have always interested me. A few of these topics are discussed below.
- Fred Sanders' Contributions to Synoptic Meteorology: Perspectives on His Cold-Frontal Research: The manuscript that started my renewed interest in cold fronts. [PDF, text only; no figures]
- A Review of Cold Fronts with Prefrontal Troughs: [PDF, text only; no figures]
- Cold Fronts with and without Prefrontal Troughs in the Central United States
- Airstream Boundaries versus Fronts: What does the nature of the large-scale flow (confluence/diffluence) have to say about the airstreams (colloquially known as conveyor belts) within extratropical cyclones?
SCALE INTERACTIONS: My Ph.D. thesis explored the interaction between the synoptic scale and the mesoscale in forming different cyclone/frontal conceptual models. (I've since collaborated with Heini Wernli and Fuqing Zhang on modeling these structures in baroclinic channel models.) Since coming to NSSL in 1996, I have tried to apply my knowledge of synoptic and mesoscale processes to understanding the convective scale.
- Synoptic Regulation of the 3 May 1999 Tornado Outbreak: Paul Roebber, Romu Romero, and I used high-resolution mesoscale numerical model forecasts as guidance in convective-initiation and convective-mode forecasting during the 3 May 1999 tornado outbreak in Oklahoma
- Intraseasonal Variability of the North American Monsoon over Arizona: Pam Heinselman received her Ph.D. while working with me on how to forecast convection during the monsoon season. Not surprisingly, the synoptic-scale environment says alot about where convection will form.
- A Climatology of Cold-Season Bow Echoes: Pat Burke earned his M.S. thesis looking at the synoptic and storm-scale conditions that favor cold-season bow echoes.

THE INTERMOUNTAIN PRECIPITATION EXPERIMENT (IPEX): An investigation of the structure, evolution, dynamics, microphysics, and precipitation associated with orographic precipitation and lake-effect snowbands in the Wasatch Mountains and Salt Lake Valley, Utah. My research has been focused on IPEX IOP 4 on 14 February 2000. The cold front associated with this storm produced a tornadic bow echo in southern Idaho, as well as strong winds in northern Utah. We found that evaporation/sublimation of the falling precipitation in the dry subcloud layer (characteristic of the Great Basin) was important in controlling the distribution of precipitation in the lowlands versus the mountains (Schultz and Trapp 2003). The evaporation of precipitation in the subcloud layer was also responsible for giving the cold front an unusual forward-tilting structure. Future research will investigate the evolution of this weather system from landfall from over the Pacific Ocean, through the complex terrain of the Sierra Nevada and Great Basin, to northern Utah.
IMPROVEMENTS TO OPERATIONAL FORECASTING: One of the goals of synoptic-dynamic meteorology is to perform research that leads to better weather forecasts. NSSL is co-located with the National Weather Service/Storm Prediction Center, which forecasts severe winter and convective weather across the United States. Some of my research projects have involved collaborations with forecasters in the National Weather Service.
- The Future of Operational Numerical Weather Prediction: This essay examines the role of both high-resolution and ensemble modeling systems in operational forecasting. Written with Paul Roebber, Brian Colle, and David Stensrud.
- Conditional Symmetric Instability: Not all forecasting diagnostics are necessarily useful. This is my article on this abused and misunderstood concept for understanding and forecasting heavy precipitation. Written with Phil Schumacher of the NWS Sioux Falls Forecast Office.
- Moisture Flux Convergence: Like conditional symmetric instability, I believe that moisture flux convergence has been misused as a diagnostic. This misuse is especially relevant when applied to forecasting convective initiation. Pete Banacos of the Storm Prediction Center and I explored the history of moisture flux convergence and why it is not appropriate for forecasting convective initiation.
- Spatial Bias Errors in Operational Forecast Models: Forecasters talk about model bias errors all the time in their forecast discussions. Do they know what the spatial bias errors really look like? This work is a collaboration with Kim Elmore and Mike Baldwin. [PDF]
- Snow Forecasting: There are many difficulties with trying to forecast snow depth accurately. One is snow density. The other is snow microphysics. This work is collaboration with Paul Roebber, Sara Bruening, John Cortinas, Eric Ware, and Harold Brooks.

PREVIOUS RESEARCH INTERESTS

Cyclone/Frontal Conceptual Models: My Ph.D. thesis research. How to use the large-scale flow (confluence/diffluence) as an indicator of what type of cyclone/frontal structure (Shapiro--Keyser/Norwegian) might result.
Superstorm of March 1993: Diagnosing the failure of numerical model forecasts of a spectacular cyclogenesis over the Gulf of Mexico.
A climatology of drizzle in the United States and Canada: with Addison Sears-Collins of the University of Virginia.
Reexamining the cold conveyor belt: The circulation through extratropical cyclones is not what you might have thought it was.
Cold Surges: Observational and numerical modeling research on North and Central American cold surges and tehuantepecers (wind storms in the Gulf of Tehuantepec, Mexico).
Weekend Precipitation: Does it really rain more on weekends? Check out the map to see if your location experiences more than its share of rainy weekends! (Published in the Annals of Improbable Research.)
Western US Fronts and Cyclones: How do fronts and cyclones pass over the Rocky Mountains and reform in their lee?
Upper-Level Frontal Conceptual Models: Examination of the Shapiro (1982) conceptual model of upper-level frontogenesis for different flow regimes.
Inertial Instability: Russ Schumacher and I have performed a climatology of inertial instability and examined the possible relationship between inertial instability and severe storms.
Henry's Rule: What processes are occurring when a mobile shortwave trough displaces a stationary cutoff cyclone over the Southwest U.S.? Follow this work in progress.
Mobile Trough Genesis: Fred Sanders and I consider the synoptic environments and thermal-advection patterns associated with a climatology of 186 mobile trough births. Can features that are inherently baroclinic be generated by barotropic processes?
Lightning in Winter Storms: Under what conditions do lightning and snow occur simultaneously?
January Thaw: What is the nature of a climatological warm period during late January across the Northeast United States?
Flash Floods and Potential Vorticity: Do mid- and upper-tropospheric potential vorticity anomalies precede flash floods? Our research suggests, "Yes, in some cases." But this work poses many more unanswered questions.

David Schultz's homepage.

Comments or Questions Last updated 23 November 2004. DMS.
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