SEMINAR SERIES and COLLOQUIA

In 2012, an observing-systems component was added to the activities of the annual NOAA/Hazardous Weather Testbed Spring Forecasting Experiment (SFE). One of the systems tested is a low-cost radiosonde system from InterMet Systems, which is being used more in research applications as an alternative to the reliable, but costly, Vaisala RS92 system. The collection of soundings in pre-convective and near-storm environments will be an important component of upcoming field projects and money could be saved by using an InterMet system. However, little is known about how the soundings from the InterMet radiosondes compare to the Vaisala soundings. The first part of this talk will cover an intercomparison of these two sounding systems performed last spring in the HWT/SFE and show that the InterMet radiosonde profiles compare very favorably to the Vaisala profiles.

The second part of this talk covers an evaluation of forecasts over two spring seasons from five convection-allowing configurations of the WRF-ARW model that vary only by the turbulence parameterization scheme, including three "local" schemes (MYJ, QNSE, MYNN) and two schemes that include "non-local" mixing (YSU and ACM2). CAPS ran these forecasts as part of the suite of convection-allowing model forecasts provided for HWT/SFE activities in 2011 and 2012. The forecasts are compared to radiosonde observations upstream from deep convection to gain a better understanding of the thermodynamic characteristics of these schemes in this regime. The results show that the MYNN scheme alleviates the typical cool (warm), moist (dry) bias of local (non-local) schemes in afternoon/evening convective boundary layers upstream from convection, but other aspects of the forecasts are not improved, and are even degraded, with the use of MYNN.

Convective Storms & NWP Seminar Series website

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