Current Capabilities in Prediction at the National Weather Service's National Meteorological Center

Abstract

Progress since 1955 in prognosis of synoptic-scale systems at the National Weather Service's National Meteorological Center (NMC) is reviewed. The application of numerical weather prediction (NWP) to the forecasting of specific weather parameters (e.g., temperature, precipitation, wind, etc.) is also discussed and the skill of these specific forecasts is reviewed. The limitations in overall forecasting skill are pointed out. In particular, the skill in prediction of heavy precipitation with current operational NWP models requires the meteorologist at the NMC to continue to play an important role in evaluating and improving the numerical product. Results are shown from experimental precipitation forecasts with finer-mesh models, which are being developed for future use at NMC.

Impact of Satellite Temperature Sounding Data on Weather Forecasts

“…The lower the score, the more skilful the forecast. Twenty years of experience in the use of SI scores at the U.S. National Meteorological Center (NMC) indicates that the practical range between a perfect and worthless forecast at 500 mb is 20-70 (Fawcett, 1977). Table 1 shows the impact of satellite sounding data on numerical forecasts as measured by the reduction in rms geopotential height errors, a positive impact representing a reduction in the error when satellite sounding data are included.…”

“…1 and 2. Figure 1 shows the mean annual SI score of the NMC's 36 h forecasts at 500 mb during the period 1955-76 (from Halem et al, 1978; extension of data presented by Fawcett, 1977). A general trend toward lower SI scores, i.e., improved forecasts, can be seen during the period.…”

“…GISS obtained a positive impact of 1.9 points in SI, representing a reduction from 39.6 to 37.7. Halem et al (1978) imply that GISS's greater positive impact is the result of a better assimilation and analysis Halem et al, 1978; extension of data presented by Fawcett, 1977. ) FIG.…”

letters to the editor1

“…Now that I have the floor, may I urge that attempts be made to evaluate the impact of weather satellites on weather forecasting? NWS reports (Fawcett, 1977;Snellman, 1977;Cook and Smith, 1977;Shuman, 1978), which have revealed little weather forecast improvement over the past 10-15 years, do not mention weather satellites. This is surprising considering that the satellites have been justified largely because they would greatly aid local forecasting.…”

Some Trends in Forecast Skill at the National Severe Storms Forecast Center

“…Since the implementation of numerical weather prediction techniques 20 years ago, a steady increase has been noted in the accuracy of forecasts of synoptic scale systems (Fawcett, 1977;Shuman, 1978). The skill in predicting the 36 h circulation pattern at 500 mb has roughly doubled since the 1950s.…”