Laserfiche WebLink
<br />Two views emerged in regards to initiaIization. One was that past storms could be <br />simulated with a moderate effort. The second was that the initialization was a. significant <br />problem and that more progress could be made by watching for good cases in the: future <br />and then perturbing the conditions to make the storm rain more than it actually did or to <br />move the storm from one location to another. Both views have merit and both should be <br />considered worthwhile. A caution was raised that some of the past storms may not have <br />enough information available for simulations. <br /> <br />The discussion of cloud microphysics had two thrusts. If higher elevations are involved <br />and some of the precipitation could fall as ice, thc..'ll the more sophisticated microphysics <br />versions will be required. If temperatures are warm enough that all precipitation will be <br />rain, then the group had more diversity in their opinions about the need for sophisticated <br />microphysics. The need to understand how the storms change as they occur at different <br />elevations led to more agreement about the need to use advanced cloud microphysics. <br /> <br />The importance of surface vegetation and soil moisture was raised as a concern but no <br />uniformity of opinion was reached. Several paJticipants thought the sensitivity of the <br />models to variations in these parameters should be explored. The main idea is that dry soil <br />could lead to warmer surface temperatures and could lead to larger inflow wind speeds <br />and perhaps a way to give preferential locations for storm development. Everyone was <br />concerned and uncertain how information about soil moisture could be obtained. <br /> <br />Experience in the Black Hills area indicates that 2D and 3D model simulations can bc~ <br />important to understand large storm characteristics. Due to cost and time involved in the <br />simulations, many more 2D simulations can be done for given resources but the 3D is <br />needed to get the most information about stornl structure and the three necessary storm <br />properties of depth, area, and duration. A critical relninder that the Black Hills do not <br />extend above 7,500 feet is always needed. One conclusion is that 2D simulations. may <br />have utility when applied to Colorado's high e11:vation topography. <br /> <br />The capability to verify large storm events is related to the current system of radars, <br />surface and upper air observations, and analysis of these data. The new WSR-88D radars <br />(Cheyenne, WY; Denver, Pueblo, and Grand Junction, CO) have a high probability of <br />capturing most storms and will observe storm area aJld duration well with total <br />precipitation somewhat less accurate due primarily to effects of ice and hail. The radar <br />will also provide observation of wind in the stomlS that can be compared with model <br />simulations. The conclusion of this discussion was that a major effort should be made to <br />capture all data related to future large storms. <br /> <br />The discussion of time and cost were not as definitivl: as the other topics. The discussion <br />centered on ideas put forward by CSU and NCAR. Much of the discussion centc~red on <br />the time and cost to simulate storms from the past. This dealt with the question of <br />initializing the models. Each group agreed that once one of the large storms had been <br />simulated well then others would be easier and quicker. Each group agreed that <br /> <br />22 <br />