Search Results
You are looking at 1 - 7 of 7 items for
- Author or Editor: Leonard W. Snellman x
- Refine by Access: All Content x
Changes in the hemispheric zonal wind-profile were used at the USAF South Ruislip Weather Central in England as one forecast tool to help in constructing prognostic charts for 48 hours and occasionally for 96 hours. The successes and failures of this technique during the period February to October 1952 are discussed. Suggestions for the improvement of its use on a daily basis are put forth.
Changes in the hemispheric zonal wind-profile were used at the USAF South Ruislip Weather Central in England as one forecast tool to help in constructing prognostic charts for 48 hours and occasionally for 96 hours. The successes and failures of this technique during the period February to October 1952 are discussed. Suggestions for the improvement of its use on a daily basis are put forth.
Meteorological support for the record-breaking, nine-day, nonstop, non-refueled flight around the world by Dick Rutan and Jeana Yeager in the Voyager aircraft 14–23 December 1986 is described. The strict meteorological criteria demanded by the flight restrictions of the unique Voyager aircraft and the facilities and meteorological tools used are discussed. A detailed description of the weather encountered during the world flight and the meteorological reasoning involved during selection of critical flight tracks are given. Satellite pictures and operational weather charts are used in an attempt to retain the authenticity of the meteorological background of this historic flight.
Meteorological support for the record-breaking, nine-day, nonstop, non-refueled flight around the world by Dick Rutan and Jeana Yeager in the Voyager aircraft 14–23 December 1986 is described. The strict meteorological criteria demanded by the flight restrictions of the unique Voyager aircraft and the facilities and meteorological tools used are discussed. A detailed description of the weather encountered during the world flight and the meteorological reasoning involved during selection of critical flight tracks are given. Satellite pictures and operational weather charts are used in an attempt to retain the authenticity of the meteorological background of this historic flight.
The impact of increasing automation of meteorological guidance on manual preparation of operational weather forecasts is discussed. There appears to be some evidence that forecasters are abdicating their meteorological input into the final forecast as automated guidance increases in quantity and quality. Results of a National Weather Service Western Region program to stimulate more forecaster input into the final forecast are given. Suggestions are made regarding “interactive” forecasting using on-station computers in the upcoming Automation of Field Operations and Services (AFOS) era.
The impact of increasing automation of meteorological guidance on manual preparation of operational weather forecasts is discussed. There appears to be some evidence that forecasters are abdicating their meteorological input into the final forecast as automated guidance increases in quantity and quality. Results of a National Weather Service Western Region program to stimulate more forecaster input into the final forecast are given. Suggestions are made regarding “interactive” forecasting using on-station computers in the upcoming Automation of Field Operations and Services (AFOS) era.
A “mean-wind” technique is presented for estimating (for a constant-pressure level) the position and strength of the core of maximum winds between two rawinsonde stations located four to nine latitude degrees apart. An example of the application of the method is given, and shortcomings of the method are described. To test the method, 37 computations were made. The resulting core speeds and positions are compared with Project “Jet-Stream” flight winds and “Whooper” reconnaissance winds. The mean speed-error of the 37 computations is −3.5 kn and the RMS error is 17 kn. It is concluded that the “mean-wind” technique is operationally feasible and that its employment in conjunction with other analysis techniques now in use will contribute to analysis in the jet-stream region.
A “mean-wind” technique is presented for estimating (for a constant-pressure level) the position and strength of the core of maximum winds between two rawinsonde stations located four to nine latitude degrees apart. An example of the application of the method is given, and shortcomings of the method are described. To test the method, 37 computations were made. The resulting core speeds and positions are compared with Project “Jet-Stream” flight winds and “Whooper” reconnaissance winds. The mean speed-error of the 37 computations is −3.5 kn and the RMS error is 17 kn. It is concluded that the “mean-wind” technique is operationally feasible and that its employment in conjunction with other analysis techniques now in use will contribute to analysis in the jet-stream region.
Abstract
The physical reason for quasi-geostrophic vertical motion is reviewed. Various techniques for estimating synoptic-scale vertical motion are examined, and their utility (or lack thereof) is illustrated by a case study. The Q-vector approach appears to provide the best means of calculating vertical motions numerically. The vertical motion can be estimated by eye with reasonable accuracy by examining the advection of vorticity by the thermal wind or by examining the relative wind and the isobar field on an isentropic chart. The traditional form of the omega equation is not well suited for practical calculation.
Abstract
The physical reason for quasi-geostrophic vertical motion is reviewed. Various techniques for estimating synoptic-scale vertical motion are examined, and their utility (or lack thereof) is illustrated by a case study. The Q-vector approach appears to provide the best means of calculating vertical motions numerically. The vertical motion can be estimated by eye with reasonable accuracy by examining the advection of vorticity by the thermal wind or by examining the relative wind and the isobar field on an isentropic chart. The traditional form of the omega equation is not well suited for practical calculation.
Abstract
No abstract available
Abstract
No abstract available
