Search Results
You are looking at 1 - 10 of 195 items for
- Author or Editor: Lance Bosart x
- Refine by Access: All Content x
Consensus (the average of all forecasts) skill levels in forecasting daily maximum and minimum temperature, precipitation probability across six class intervals, and precipitation amount at the State University of New York at Albany are reviewed for the period 1977–82. Skill is measured relative to a climatological control. Forecasts are made for four consecutive 24 h periods for Albany, N.Y., beginning at 1800 GMT of the current day.
For minimum temperature, the skill levels average 57%, 41%, 26%, and 15%, respectively, for 24, 48, 72, and 96 h in advance. For maximum temperature, a more limited sample yields corresponding skill levels of 84%, 49%, 34%, and 19% for 12, 36, 60, 84 h ahead. Linear regression analysis yields little in the way of a definitive trend, given the smallness of the explained variance. Comparison with other readily available objective and subjective operational guidance establishes the credibility of the consensus forecast.
Consensus (the average of all forecasts) skill levels in forecasting daily maximum and minimum temperature, precipitation probability across six class intervals, and precipitation amount at the State University of New York at Albany are reviewed for the period 1977–82. Skill is measured relative to a climatological control. Forecasts are made for four consecutive 24 h periods for Albany, N.Y., beginning at 1800 GMT of the current day.
For minimum temperature, the skill levels average 57%, 41%, 26%, and 15%, respectively, for 24, 48, 72, and 96 h in advance. For maximum temperature, a more limited sample yields corresponding skill levels of 84%, 49%, 34%, and 19% for 12, 36, 60, 84 h ahead. Linear regression analysis yields little in the way of a definitive trend, given the smallness of the explained variance. Comparison with other readily available objective and subjective operational guidance establishes the credibility of the consensus forecast.
Abstract
A case study is made of the Texas coastal rainstorm of 17–21 September 1979 in which upward of 50 cm of rain inundated the area. The precipitation developed along a weak baroclinic zone left in place by a trough passage at higher latitudes. A cold upper tropospheric vortex over the southwestern United States enabled relatively cooler and drier air to flow southward over the warmer waters of the western Gulf of Mexico. Differential heating and moistening along a Texas coastal front slowly destabilized the atmosphere and set the stage for a convective scale response.
A mesoscale cyclonic circulation formed near the southwestern end of the coastal front and along the western edge of a convective cloud cluster. Embedded within this circulation was a short-lived mesocyclone which achieved tropical storm strength for 12 h. The case is a specific example of a mesoscale circulation in which origin and evolution is controlled by synoptic scale patterns. The mesocale disturbance, once formed, moves northeastward parallel to the coast. It gradually moves into an environment more favorable for quasi-geostrophic intensification as the circulation expands in area.
Abstract
A case study is made of the Texas coastal rainstorm of 17–21 September 1979 in which upward of 50 cm of rain inundated the area. The precipitation developed along a weak baroclinic zone left in place by a trough passage at higher latitudes. A cold upper tropospheric vortex over the southwestern United States enabled relatively cooler and drier air to flow southward over the warmer waters of the western Gulf of Mexico. Differential heating and moistening along a Texas coastal front slowly destabilized the atmosphere and set the stage for a convective scale response.
A mesoscale cyclonic circulation formed near the southwestern end of the coastal front and along the western edge of a convective cloud cluster. Embedded within this circulation was a short-lived mesocyclone which achieved tropical storm strength for 12 h. The case is a specific example of a mesoscale circulation in which origin and evolution is controlled by synoptic scale patterns. The mesocale disturbance, once formed, moves northeastward parallel to the coast. It gradually moves into an environment more favorable for quasi-geostrophic intensification as the circulation expands in area.
Abstract
No abstract available
Abstract
No abstract available
Abstract
Average kinematic vertical motion and relative vorticity profiles are presented for a long-lived midlatitude convective complex. A breakdown into active convective and stratiform precipitation regions shows very good agreement in the vertical motion profiles with published results for tropical convective systems.
Abstract
Average kinematic vertical motion and relative vorticity profiles are presented for a long-lived midlatitude convective complex. A breakdown into active convective and stratiform precipitation regions shows very good agreement in the vertical motion profiles with published results for tropical convective systems.
Abstract
An analysis of skill in predicting daily temperature and precipitation is presented for six years (1969–1975) of forecasts made for the Albany County Airport by students and faculty in the Department of Atmospheric Science of the State University of New York at Albany. The daily consensus forecast (made up by averaging the forecasts of all forecasters) shows no significant secular increase in skill for temperature. An apparent increase in the consensus skill in precipitation forecasting is noted with most of the increase occurring in the spring 1972 semester. Possible reasons for this increase are discussed. The skill (defined as the percentage improvement over a persistence climatological forecast) of the ensemble of forecasters over a persistence climatological control is near 50% for the first day decaying to 10% and near zero by the 3rd and 4th day for precipitation and to just under 10% for temperature by the 4th day. These results are consistent with the results presented by Sanders (1973).
Some relationship is found for skill to be a function of the variability of the daily temperature about the climatological mean. Skill, however, appears to be insensitive to the frequency of days with radiational cooling, a major local forecast problem. likewise skill appears to be independent of daily rainfall amount or frequency. These findings are consistent with those found for Boston by Sanders (1973).
Finally, the trend towards a plateau in skill noted by Sanders (1973) is confirmed for a different location.
Abstract
An analysis of skill in predicting daily temperature and precipitation is presented for six years (1969–1975) of forecasts made for the Albany County Airport by students and faculty in the Department of Atmospheric Science of the State University of New York at Albany. The daily consensus forecast (made up by averaging the forecasts of all forecasters) shows no significant secular increase in skill for temperature. An apparent increase in the consensus skill in precipitation forecasting is noted with most of the increase occurring in the spring 1972 semester. Possible reasons for this increase are discussed. The skill (defined as the percentage improvement over a persistence climatological forecast) of the ensemble of forecasters over a persistence climatological control is near 50% for the first day decaying to 10% and near zero by the 3rd and 4th day for precipitation and to just under 10% for temperature by the 4th day. These results are consistent with the results presented by Sanders (1973).
Some relationship is found for skill to be a function of the variability of the daily temperature about the climatological mean. Skill, however, appears to be insensitive to the frequency of days with radiational cooling, a major local forecast problem. likewise skill appears to be independent of daily rainfall amount or frequency. These findings are consistent with those found for Boston by Sanders (1973).
Finally, the trend towards a plateau in skill noted by Sanders (1973) is confirmed for a different location.
Abstract
Abstract
Abstract
No Abstract available.
Abstract
No Abstract available.
