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Univ. of Utah: "1998 Workshop: Weather Prediction in the Intermountain West"

Final Report

1. Project objectives and accomplishments

The primary objective of this COMET Partners Project was to host the 1998 Workshop on Weather Prediction in the Intermountain West. This year's workshop was organized to discuss issues related to operational meteorology over the Intermountain West with an emphasis on winter storms and winter-season quantitative precipitation forecasting (QPF). The workshop was held on 30 October 1998 at the University of Utah and was attended by approximately 100 people including NWS personnel from the Billings, Boise, Elko, Great Falls, Las Vegas, Oxnard, Missoula, Pendleton, Pocatello, Reno, and Salt Lake City forecast offices. Several invited speakers gave talks specifically addressing the western US QPF problem including Larry Dunn (SLCFO), Cliff Mass (University of Washington), Geoff Dimego (NCEP), and Brett McDonald (COMET/NCEP). A workshop program is included in section 3 and summarizes the talks and poster sessions that were presented.

A special meeting of Western Region SOOs was held on the afternoon prior to the workshop to have focused discussion of major scientific issues facing meteorologists in the Intermountain West and to more clearly define future cooperative research programs for the NOAA Cooperative Institute for Regional Prediction. This special meeting, along with the workshop, identified the following objectives for advancing weather prediction over the Intermountain West:

I. Improve analysis over complex terrain.

There are many scientific and technical issues that need to be resolved to produce good analyses in complex terrain. Issues such as what resolution is sufficient, how to properly interpret data from varying elevations to a grid, quality control, and integrating radar data, need to be systematically examined. The NWS can directly benefit from this effort, since the current 10 km AWIPS LAPS analysis does not work well and western region FOs will need a viable alternative.

II. Improve understanding of synoptic and mesoscale weather systems over the western United States.

Very little work has been done in the Intermountain West to develop meteorological conceptual models that the forecasters can use. Specific areas where research is needed include

A. Cyclone interaction with complex terrain
B. Local circulations over the Intermountain West
C. Heavy orographic snow forecasting

III. Improve model forecast in complex terrain.

There was much discussion about the role of mesoscale models (local or NCEP) and how to best proceed to improve and use model forecasts in the west. There were many issues and suggestions, but currently no group seems to be examining the issue systematically. This is a very complex topic, but some of the issues raised were: resolution versus ensemble, Eta versus sigma coordinates, at what point does increased resolution produce smaller gains, which parameterizations schemes work better in complex terrain. The model goals should be driven by the service problems identified in number II above.

2. Benefits and Problems Encountered

a. University perspective

We believe this has been the most successful workshop of the five that the University of Utah has hosted. The focused nature of the workshop (winter weather), the meeting with SOOs on the preceding day, and the building of discussion time into the workshop schedule, allowed us to maximize feedback from the operational community and define future research goals.

b. NWS perspective

The overall quality of presentations was higher this year than in previous years. A number of NWS individuals remarked that every presentation was very good and worthwhile. The longer time given to some of the invited talks worked out well, with a greater opportunity to cover a topic in depth than is typically the case in short oral presentations. Without question, this was an excellent workshop.

3. Workshop Program

8:00-8:30 Registration

8:30-8:45 Opening Remarks
Jim Steenburgh, University of Utah
Tom Potter, Director, NOAA CIRP
Andy Edman, NWS Western Region Headquarters

8:45-9:15 Operational Forecast Issues

8:45-9:15 Invited Talk: Present day status of wintertime QPF prediction over the Intermountain West. Larry Dunn, NWSFO Salt Lake City, UT.

9:15-9:30 SPC winter weather mesoscale discussions. Kurt Van Speybroeck and Greg Carbin, NWS/NCEP Storm Prediction Center.

9:30-9:45 Mountain weather and avalanches. Bruce Tremper, Utah Avalanche Forecast Center.

9:45-10:05 Discussion/Poster Introductions

10:05-10:30 Break

10:30-12:15 Numerical Weather Prediction

10:30-11:00 Invited Talk: High resolution mesoscale modeling over the Pacific Northwest. Cliff Mass, University of Washington.

11:00-11:30 Invited Talk: An update on modeling activities at NCEP. Geoff DiMego, NCEP.

11:30-12:00 Invited Talk: QPF verification in the western United States. Brett McDonald, COMET/NWS, and John Horel, University of Utah and NOAA Cooperative Institute for Regional Prediction.

12:00-12:15 Discussion

12:15-1:00 Lunch

1:00-2:45 Observing Systems

1:15-1:30 WSR-88D snow prediction in the west. Steve Vasiloff, NOAA National Severe Storms Laboratory.

1:30-1:45 Quantitative precipitation estimation by the Reno WSR-88D: The 1997 New Year's Flood. David Kingsmill and Arlen Huggins, Desert Research Institute Atmospheric Science Center

1:45-2:00 Derived digital satellite data use in western region forecast offices. Kevin Schrab, NWS Western Region Headquarters.

2:00-2:15 The Utah Mesonet. Mike Splitt and John Horel, University of Utah and NOAA Cooperative Institute for Regional Prediction.

2:15-2:30 Application of an analysis/forecast system in the complex terrain of NW Utah. Steve Lazarus, Carol Ciliberti, and John Horel, University of Utah and NOAA Cooperative Institute for Regional Prediction.

2:30-2:45 Discussion

2:45-3:15 Break

3:00-4:30: Structure and analysis of winter storms

3:15-3:30 Invited Talk: Forecasting lee cyclogenesis. David Schultz and Charles Doswell, NOAA National Severe Storms Laboratory.

3:30-3:45 Arctic outbreaks west of the continental divide in the MesoEta model. Tim Barker, NWSFO Missoula, MT.

3:45-4:00 A composite study examining five heavy snowfall patterns for south central Montana. Jonathan Van Ausdall and Thomas Humphry, NWSFO Billings, MT.

4:00-4:15 Numerical investigation of the 25 October 1997 blowdown event over the Colorado Park Range using RAMS. Michael Meyers, NWSFO Grand Junction, CO, John Snook, NOAA Forecast Systems Laboratory, Doug Wesley, UCAR/COMET, and Greg Poulos, Colorado Research Associates.

4:15-4:30 The effects of vertical motion and microphysical processes on precipitation type during a western Nevada snow storm. Thomas Cylke, NWSFO Reno, NV.

4:30-5:00 Closing Discussion