HMT-West 2007 Underway – A Promising New Experimental Product is Tested


February 12, 2007

Basin scale HMT-West 2007 map The NOAA Earth System Research Laboratory (ESRL) is currently computing bulk upslope water vapor flux along the California coastline with a new real-time product developed for the Hydrometeorological Testbed (HMT) Program. This experimental product was based on four winters of analysis and combines information on storm forcing (boundary layer winds aloft) measured by wind profiling radars and fuel (water vapor) measured by GPS-Met receivers, and is well correlated with rainfall rates in the nearby, downwind mountains. The product, which graphically displays the data and is updated hourly, could potentially become a useful aid for predicting and assessing precipitation amounts in the mountains of this area; and is already showing promising results during a large storm that has recently hit the area.

Background:
HMT is a NOAA demonstration program designed to aid flood forecasting by accelerating the infusion of new technologies, forecast models, and scientific results from the research community into daily operations of the National Weather Service, including Weather Forecast Offices, River Forecast Centers and the National Centers for Environmental Prediction.

HMT-West, which is currently underway through late March 2007, is in its second full year, with at least two more years planned. This year is focused on collecting more observations at the higher altitudes of the basin, where snowfall is more common. Several research-grade observing instruments from ESRL and the National Severe Storms Laboratory (NSSL) have been deployed to the region. Additional observing systems include raindrop and snowflake disdrometers, various precipitation gauges, soil moisture/temperature sensors, stream level loggers, standard surface meteorological stations, and a radiosonde system. The measured parameters are vital ingredients for accurate predictions of runoff and flooding that are too sparsely available, too distant, or entirely absent for most watersheds. The USGS is also collecting rainwater samples for chemical analysis. New high-resolution weather prediction models from ESRL are also being tested in the project and compared with exiting models used by the NWS.

Significance:
The upslope water vapor flux product could become a useful forecasting tool that could help mitigate societal impacts from wildfires, flooding, and debris flows (mud slides). This research supports NOAA's mission goal of serving society's need for weather and water information.

Contact: Timothy Schneider More Information: