National Weather Service |
In This Issue |
Diane Innes Cooper, Publisher |
Remote Backup Capabilities Are Now Available For RFC’s
By Jeff McMurphyPreviously, the plan for an RFC backup system was for the NWS Office of Hydrology (OH) to have the capability to load each individual RFC’s AWIPS system with the specific programs, tools, and data onto the OH AWIPS system. When backup operations were needed, an RFC would contact OH to initiate the loading of that RFC’s system and begin the data acquisition processes. RFC forecasters would then travel to OH in the Washington D.C. area, where they would use OH’s system to generate and transmit forecasts and products. In theory this seemed like a good idea, yet the logistics of maintaining accurate systems for each of the 13 RFC’s was too complicated. Another problem was the associated expenses of lodging and travel costs for the RFC personnel. Hence, this functionality could only be used in situations when the cost could be justified, typically not for the one to two day events which were most common. Thus, in these situations, the NWS WFO’s were on their own to issue river forecasts without the guidance of a hydrologic model.
Recently, desktop PC processing power, storage capabilities, and software availability began to reach a level in which developing a backup system for local use at an RFC became a true possibility. In 2001, ABRFC began developing a backup Linux desktop PC. Linux was chosen because OH and the Forecast System Laboratory (FSL) had already begun the process of porting NWS applications to Linux. In May of 2002, this local desktop system was tested and proven successful for being able to provide ABRFC forecast and guidance products to customers in a timely and transparent manner. (Please refer to “ABRFC Operational Backup Test Is Successful” article in the Fall 2002 publication of “The Gage,“ for more details.)
Since this first test, ABRFC has taken the backup capability to yet another plateau, this time in the laptop PC arena. The ABRFC has created a Linux laptop with the same functionality, yet with much faster processing speeds, nearly 7 times faster, than the current Operational AWIPS system. This system downloads data from the Internet, runs the hydrologic model as well as supporting programs such as NMAP, XNAV, XDAT, FCSTPROG XSETS, P2 and MPE and issues a full suite of operationally critical products and forecasts including RVFs, FFGs, HMDs, and HCMs. The AWIPS D2D Display is not utilized, yet radar reflectivity and satellite images can be displayed via a variety of web sites. The national Flood Outlook Product cannot be produced as ArcView is unavailable for Linux. Product dissemination is accomplished by using ABRFC developed scripts which drop products on a SRH server where they are picked up by a backup office’s LDAD. Products are then moved through the protective firewall from LDAD and into AWIPS via common LDAD/AWIPS ingest software.
The advantage of the laptop portability was utilized during the test conducted on March 11, 2003. The test mimicked a total office-loss scenario and operations were conducted from a hotel room with a high speed internet connection as well as a second voice line for coordination purposes. The system was cold-started and made ready for use in one hour and ten minutes. Cold-start is defined as the system having no model files, no observed data, no files of estimated radar precipitation, no Quantitative Precipitation Forecasts (QPF) files, and not connected to the Internet. Ready-for-Use is defined as: the hydrologic model run, for the entire river forecast system, is complete along with a current set of data and the system is functional and ready for interactive use by forecasters with data ingest and dissemination processes up and running. This cold start is possible because on a regular basis, ABRFC’s operational hydrologic model information as well as other data is uploaded from a desktop version of the Linux backup system which we locally maintain. (Note: A data conversion problem exists for sending files from HP UNIX to Linux. Hence, once we transition to performing routine operations on a Linux platform, we will then be able to use this data rather than maintaining the desktop backup system.) Not only did this laptop PC perform all operational functionality, but it was also able to perform as a “server” in the sense of allowing multiple laptops to remotely login and allowing these “clients” to be used as additional stations from which to forecast.
With the success of this latest test, SRH has provided the funding for the other Southern Region RFC’s, West Gulf River Forecast Center (WGRFC), Southeast River Forecast Center (SERFC), and Lower Mississippi River Forecast Center (LMRFC), to have a laptop Backup PC. Hence, by the time you receive this newsletter, ABRFC will have configured these RFC laptop PC’s for the specialized operations of each RFC and will have trained a member of each of the RFC’s in its use. Final testing and implementation of these backup systems is expected to be accomplished by July 31, 2003. So, in the near future, all Southern Region RFC’s will be able to provide services and products to the WFO’s and public in the events of an AWIPS upgrade, an AWIPS failure, or even in the case of a catastrophic event happening at an RFC’s building facilities.
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ABRFC Evaluates New Short-Term Probabilistic Forecasts
By Bill Lawrence
Figure 1: Example of the Experimental Probabilities Plot of Flow through five days for Carthage, MO. This plot was generated with three inches of QPF forecast to occur in the Second Period, between forecast hour 6 and 12. The plot in purple shows the most likely flow/river stage situation while the plot in aqua indicates the least likely flow/river stage solution.
2003 Water Supply Season
By John SchmidtThis year, a dry winter gave way to a normal spring snowpack in the Arkansas River basin by the middle of March (See Figure 1). This catch-up was thanks to a record-setting blizzard on March 17-19, 2003. Although the bulk of the snow fell north of the Palmer Divide, the one to four feet that fell in the mountains west of Colorado Springs and Pueblo was welcome moisture.
With most of the snow falling east of Salida, CO, snowmelt forecasts on the Arkansas River at Granite and Salida, CO remained about the same. However, snowmelt forecasts for the tributaries of the Arkansas River east of Salida (Grape and Chalk Creeks and Cucharas, Purgatoire and Huerfano Rivers) jumped from 71 to 94 percent-of-average snowmelt volume. Basin-wide, a slightly below-normal snowmelt season was forecast with a peak flow during the first two weeks of June. This forecast remained about the same from April to May.
The timing of the snowmelt is based on an average distribution of runoff over the past 20-50 years and therefore reflects an average daily temperature. The amount of streamflow forecast through the summer reflects a normal amount rainfall, as most of the snowpack is gone. May proved to be anything but average, especially the last two weeks, as temperatures in the Arkansas River Basin ranked "much above normal" (See Figure 2). Additionally, areas above water supply forecast points received below-normal precipitation amounts over the past 90 days (See Figure 3).
This significantly atypical temperature distribution resulted in higher and earlier than expected crest of streamflows at most water supply forecast points in the Arkansas River basin (See Figure 4). In fact, several flood forecasts and river flood warnings were issued for the Arkansas River near Canon City and Pueblo by the ABRFC and the local NWS forecast office in Pueblo, CO during the week of May 27th.
 Figure 1: Accretion and depletion of 2003 Arkansas Basin Snowpack (Courtesy NRCS). The black line denotes the actual accumulation of snowfall for the 2003 winter season. The red line indicates the 30 year average snowfall accumulation during a winter season. Hence, one can clearly see that this past winter was much closer to normal in comparison to the 2002 Season (brown line). |
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 Figure 2: May 2003 Temperature Departure by Climate Zone. Arkansas Basin in Colorado is outlined in bold black, depicting the much above normal temperatures received in May of 2003. (courtesy NCDC) |
 Figure 3: Last 90 days percent-of-normal precipitation, Arkansas River Basin, in Colorado. Normal precipitation in the headwaters of the Arkansas River is typically three to four inches of precipitation. Much of this area has seen only one to two inches of precipitation with isolated areas receiving a half of an inch. |
 Figure 4: Forecast percent chance of exceedance and observed streamflows. This forecast was issued April 1st with weekly water supply estimates. The various colors depict the probability of occurrence based on analysis of historical data. The triangle data points indicate the actual observed volume while the circles data points indicate the volume generated based on native flow calculations. Native Flow is defined as the flow which would have been generated if no human intervention had occurred. |
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Arconyms in this Edition
| ABRFC - Arkansas-Red Basin River Forecast Center AWIPS- Advanced Weather Interactive Processing System FFG - Flash Flood Guidance FCSTPROG - Software Program used to current and previous river forecast to the stage observations FSL - Forecast Systems Lab HCM - Hydrologic Coordination Message HMD - Hydrometeorological Discussion LDAD - Local Data Acquisition and Dissemination System |
LMRFC - Lower Mississippi River Forecast Center MPE - Multi–Sensor Precipitation Estimator (Used to process observed gridded precipitation) NMAP - Office of Hydrology NRCS - Natural Resources Conservation Service OH - Office of Hydrology QPF - Quantitative Precipitation Forecast RFC - River Forecast Center RVF - River Forecast Guidance from an RFC |
SERFC - Southeast River Forecast Center SRH - Southern Region Headquarters USDA - United States Department of Agriculture WFO - National Weather Service Forecast Office WGRFC - West Gulf River Forecast Center XDAT - Software program used to query the hydrologic database XNAV - Multi-Use Software Program used in RFC operations XSETS - Software program used to generate and transmit river forecasts |