92nd American Meteorological Society Annual Meeting (January 22-26, 2012)

Monday, 23 January 2012
First-Time Mobile Doppler Radar Observations of Heavy Rain-Producing Thunderstorms in Northwest New Mexico
Hall E (New Orleans Convention Center )
Jennifer Palucki, NOAA/NWSFO, Albuquerque, NM; and K. Jones and S. Vasiloff

A mobile Doppler radar was deployed near Durango, Colorado during the Southwest Colorado Radar Project in August 2010 to collect data on monsoonal thunderstorms and the resultant flash flooding in the Four Corners region. This area suffers from poor radar coverage by the National Weather Service radar network. Existing WSR-88D's can only observe upper portions of thunderstorms in the Four Corners region due to their location. The radar gap leaves forecasters with much uncertainty concerning rainfall rates, surface circulations, and other near-ground phenomena.

Led by researchers from the National Severe Storms Laboratory, the 2010 Southwest Colorado Radar Project sought to improve radar coverage during the month of August a typically active period in the heart of monsoon. There were several goals of the project, including demonstrating how local weather radar could improve rainfall estimation and increase the detection of potentially deadly flash floods. This data was provided in near real-time to the National Weather Service in Albuquerque after being blended with other regional radars in NSSL's National Mosaic and QPE system to aid in flash flood warning decisions.

Quantitative precipitation estimates collected during the afternoon of August 4th proved how valuable a Four Corners radar would be. One-hour precipitation estimates using the mobile radar data ending at 430 pm local time were near 1.5 inches over the Stone Lake RAWS site in northwest New Mexico. The site measured 1.49 inches of precipitation in this one hour time frame. Precipitation estimates using only WSR-88D data were approximately half that of the mobile radar data, estimating nearly 0.80 inches. The footprint of wetting rain differs depending on the radars in use. The displacement of the rain estimates can be attributed to the distance from the Albuquerque radar and the mobile radar to the RAWS site, as well as partial beam blocking due to terrain.

On the evening of August 1st, a night when the mobile Doppler was not operating, significant flash flooding afflicted the Farmington, New Mexico area. WSR-88D precipitation estimates suggested only up to one half inch of rain had fallen with slightly higher amounts north of the city, whereas spotters were reporting over 2 inches of rain, most of which had fallen in a 30 minute timeframe. The addition of a Four Corners radar, and subsequent higher resolution quantitative precipitation estimates, would have alluded to the gravity of the situation, and led to better decision support services during the event.

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