Non-Convective Severe Wind Composite

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Thursday, 8 January 2015: 4:30 PM
232A-C (Phoenix Convention Center - West and North Buildings)
Timothy Villaran, AWS, Davis-Monthan AFB, AZ

Non-convective severe winds are a damaging and life threatening phenomenon. The Department of Defense optimizes operations and saves money when high wind events are forecasted accurately; timely severe wind alerts safeguard personnel and assets. Forecasting winds remaining below mission thresholds allow commanders to maximize training in addition to the proper allocation of resources for their day to day operations. Synoptically, there many forcing mechanisms behind non-convective high wind events. When the major parameters related to high wind events are extracted and overlaid on a chart, called the non-convective severe wind composite, forecasters can quickly identify when multiple thresholds identifying a high wind event are being exceeded. The non-convective severe wind composite is built using a single deterministic model to extract the following parameters: level closest to the surface where model 50kts winds are met or exceeded; low-level instability to identify regions where high winds aloft could mix down; downward vertical velocity for identification of winds aloft which could be pushed to the surface; high surface pressure gradient areas which meet 50kt thresholds; areas of an increasing pressure gradient highlighting the potential for increased gradient winds; areas of frontogenesis which will aid in timing the onset of a surface boundary; and cold air advection which can force winds aloft down to the surface and can also be used in combination with frontogenesis areas to highlight a cold front. Using the model derived composite, the forecaster can identify the factors causing the wind event and compare it to observed data to make the final decision on whether a high wind event will occur. After fully implementing the use of the wind composite into the forecast process at the 25th Operational Weather Squadron, forecasting of non-convective severe wind warnings increased 14 percent from the previous five year's average for Western United States Department of Defense locations.