Third IOP of HMT-West 2008 Has BegunPosted: December 31, 2007 |
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The second intensive operating period (IOP #2) of HMT-West 2008 is complete, including up to 3 inches of liquid equivalent and over 1 foot of snow in the HMT Sierra Mountain sites, as well as rain totals in excess of 3 inches in the coastal mountains. The HMT-developed water vapor flux tool is shown in the figure for the coastal couplet of Bodega Bay (BBY) & Cazadero (CZD). This figure highlights the close correlation between the downstream mountain rainfall at Cazadero and the horizontal water vapor transport ("IWV flux") derived from simultaneous wind profiler and GPS-met water vapor data at Bodega Bay. It also highlights that the onset and cessation of precipitation corresponded well with the time period in which the integrated water vapor exceeded 2 cm, a key threshold for precipitation. You can learn more about the water vapor flux tool in the conference reprint. This figure also highlights another product developed in the HMT – the snow level product. The elevation which forms the boundary between rain and snow is a critical parameter that is factored into stream flow predictions, and can even dictate as to whether or not a flood warning should be issued. More information on this concept can be found in the research paper. |
HMT-developed water vapor flux tool for the coastal couplet of Bodega Bay (BBY) & Cazadero (CZD).
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Deployment of HMT-West 2008Posted: December 3, 2007 |
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On December 3, 2007, the NOAA Earth System Research Laboratory (ESRL) will begin field operations for the 2008 Western Hydrometeorological Testbed (HMT-West 2008). HMT-West is located in the Sierra Mountains east of Sacramento, CA. One of the most significant enhancements to HMT-West 2008 instrumentation, compared to previous seasons, is the addition of several new precipitation and soil moisture measurement sites at high elevation, providing the most comprehensive coverage of the American River Basin to date. A new site for the ESRL scanning, polarimetric, Döppler radar at Blue Canyon will provide polarimetric coverage of the entire basin of the North Fork of the American River for the first time. Polarimetric radars can provide more accurate quantitative precipitation estimates. State-of-the-art forecasting techniques, new tools to distribute information to the operational offices, and efforts to synthesize and integrate information (such as QPE), complete these efforts. 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 will be underway through mid-March, 2008, is beginning its third full year, with at least one more year planned in the West. NOAA’s Weather and Water Mission includes goals for improving the predictability of floods to better protect the public from losses of life and property. HMT is a concept designed to accelerate and enhance the testing and infusion of new technologies, models, and scientific results from the research community into daily forecasting operations of the National Weather Service, including NCEP, WFOs and River Forecast Centers. |
HMT-West 2008 Basin Scale Map
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Analysis of How CALJET/PACJET Information Was Used by NWS ForecastersPosted: August 3, 2007 |
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Marty Ralph, of the Earth System Research Laboratory, Physical Sciences Division, has co-authored with Rebecca Morss, of the National Center for Atmospheric Research, an article published in the June issue of the Journal of Weather and Forecasting, entitled "Use of Information by National Weather Service Forecasters and Emergency Managers during CALJET and PACJET-2001." The article presents results from a study of how information from the California Land-falling Jets (CALJET) and Pacific Land-falling Jets (PACJET) field experiments has been utilized in real time by National Weather Service (NWS) forecasters and forecast users. Case studies of critical forecasting periods were traced from data ingestion and processing, to forecast generation, communication, and use. The study also illustrates the important role forecasters play in interpreting and applying both technical and informal information in order to best address users’ real-time needs. Winter storms in western North America can often be severe enough to create hazards that potentially lead to loss of life or property. From 1997-2003, CALJET and PACJET studied land-falling winter storms along the Pacific coast providing data that supplemented the NWS operational network. The results of this analysis show that information obtained from CALJET and PACJET helped improve the quality of forecasts and aided decision-makers. CALJET and PACJET are examples the successful transfer of NOAA research to operations and support NOAA’s mission goal of serving society’s need for weather and water information. These studies were the precursory field experiments for what has now become the NOAA Hydrometeorology Testbed (HMT) program. |
Schematic illustrating how NWS forecasters’ use of observations and numerical model output varies with forecast leadtime.
Because the manner in which forecasters weigh different information depends on the situation, leadtimes on the x-axis are
approximate. The warning and watch timescales are also approximate, representing typical leadtimes for potentially hazardous
weather associated with landfalling West Coast winter storms.
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NOAA Partnering with KPIX TV Station, San Francisco, CA to Share Radar DataPosted: March 13, 2007 |
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NOAA has partnered with KPIX-TV (CBS-5) to pave new ground. KPIX, the San Francisco area CBS television owned and operated station, has installed the first private weather radar in the region. This radar fills a critical gap in the NOAA NEXRAD coverage in this region. The "gap" exists because of the complex terrain in this area which obstructs radar beams, the location of existing operational radars and the minimum scanning elevation allowed on the operational radars. The weather that affects this region comes in low off the Pacific Ocean, literally under the radar. Because of it's location and it's ability to scan at low elevation angles, the KPIX radar can "see" the incoming weather. This augments the region's NEXRAD network and gives the National Weather Service (NWS) forecasters in the Monterey office a big advantage. An HMT pilot study helped to demonstrate the need for gap-filling radars in this region. A key objective of HMT is to provide objective, science-based recommendations for implementing improvements to observational and other tools that will improve predictions. These developments surrounding the KPIX radar constitute another first: this can be considered the first research to operations success story for a major observational facility from the HMT, a fitting outcome from the HMT Pilot Study. |
The first 0-degree elevation reflectivity data from the KPIX radar on Feb. 22, 2007. The San Francisco
Bay is in the center of the image.
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New Upslope Water Vapor Flux Observation ProductPosted: February 13, 2007 |
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NOAA/ESRL is now computing the bulk upslope water vapor flux for four of its meteorological observing stations in coastal California, including some associated with the Hydrometeorological Testbed (HMT), the Coastal Ocean Storms Program, and the Debris Flow Project. While still experimental, the product is based on four winters of analysis. This bulk upslope water vapor flux parameter, which combines information on storm forcing (winds in the controlling layer) and fuel (water vapor), is well correlated with rainfall rates in the nearby, downwind mountains. Therefore, it might be a useful aid for predicting and assessing precipitation amounts in those mountains. The flux data are graphically displayed in real-time with hourly updates. The new product is available for Bodega Bay (BBY), Point Piedras Blancas (PPB), Goleta (GLB), and Saticoy (STC). Just click on the appropriate site dot on the California map. This product is patterned after the study of Neiman et al. (2002), which found strong correlations between the strength of the upslope component of boundary layer wind (measured by wind profilers) at coastline sites and the rain rates measured by gauges downwind in the nearby coastal mountains. In the new product, profiler’s wind measurements are combined with precipitable water vapor measurements from GPS-Met instruments to obtain a bulk water vapor flux parameter. This parameter is even more strongly correlated with the downwind mountain rainfall than was the case for upslope wind alone, according to ongoing analysis of four winters of data from northern California. More information can be found on the HMT-West 2007 web page.
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Hourly conditions at the NOAA/ESRL meteorological monitoring site at Bodega Bay, CA
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