Physical Mechanisms of the 1993 Summer Floods

Mo, Kingtse C.; Nogués-Paegle, Julia; Paegle, Jan

doi:10.1175/1520-0469(1995)052<0879:pmotsf>2.0.co;2

Cited by 80 publications

(73 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This pattern became more firmly established starting around 2 June and persisted until approximately 13 June. Mo et al (1995) noted a very similar persistent 500-hPa height anomaly configuration in 1993 occurring between 26 June and 23 July (Figure 3(b)) that was preceded by transient synoptic systems in the prior weeks. This process established the 1993 event into two distinct flood phases, a transition period during 1-25 June that led to the flood build-up and the major flooding period that occurred between 26 June and 23 July that coincided with the atmospheric circulation shift (Rodenhuis, 1996).…”

mentioning

confidence: 77%

“…Mean daily 200-hPa zonal wind anomaly Mo et al (1995) examined the shift of the jet by examining the time-longitude cross-section of the 200-hPa zonal wind anomaly averaged over the latitude belt from 35°N to 40°N shown in Figure 12(b). The authors found positive anomalies during late spring at the dateline signalling the extension of the Pacific jet.…”

Section: Mean Daily 850-hpa Meridional Wind Anomalymentioning

confidence: 99%

“…soil moisture), mesoscale processes (e.g. diurnal convection), and most importantly large-scale atmospheric circulation variability that produce the most persistent precipitation anomalies across the area (Mo et al, 1995Trenberth and Guillemot, 1996;Liu et al, 1998). Extreme precipitation events are known to be affected by synopticscale atmospheric conditions (Joseph et al, 2000).…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Atmospheric aspects of the 2008 Midwest floods: a repeat of 1993?

Coleman

Budikova

2009

Intl Journal of Climatology

View full text Add to dashboard Cite

This paper identifies and documents the major large-scale atmospheric circulation characteristics that preceded and facilitated the devastating floods across the Midwestern United States along the upper Mississippi, Missouri, and Wabash River basins in the late spring/early summer of 2008. These circulation features were also placed in the context of the 1993 floods that occurred within a similar temporal and spatial domain. This process included investigating the relationship between various atmospheric conditions and the timing of flood-producing rainfall events at monthly and sub-monthly timescales. Unlike in 1993, the 2008 flood event took place 1 month earlier in the year (May), lasted over a much shorter time period, and extended eastwards into Indiana. The comparison confirmed much previous work regarding the factors associated with Midwest flooding during the early warm-season and revealed the possible influence of the state of the North Atlantic Ocean and the North Atlantic oscillation (NAO) on warm-season flooding across the Midwest. Both the 2008 and 1993 events were preceded by an NAO positive phase; the pattern switched phase about 2 months before the onset of the flooding and remained negative for the duration of the floods. While the major atmospheric conditions known to be associated with major flooding across the Midwest were present in 2008 (e.g. a strong Great Plains low-level jet), the level of their development, persistence, and geographic orientation/position was very distinct from those observed in 1993. These conditions were also embedded in different state of the remote hemispheric circulation over the Pacific North American region. Together, these variations contributed to the 2008 Midwest floods that occurred earlier in the warm season, were shorter-lived, and had an impact on a slightly different geographic area.

show abstract

mentioning

confidence: 77%

Section: Mean Daily 850-hpa Meridional Wind Anomalymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Atmospheric aspects of the 2008 Midwest floods: a repeat of 1993?

Coleman

Budikova

2009

Intl Journal of Climatology

View full text Add to dashboard Cite

show abstract

“…For instance, the widespread Great Plains flooding event of 1993 was associated with a prolonged period of strong LLJs (Arritt et al 1997). In contrast, in the drought episode of 1988, the Great Plains LLJs were only about half as strong as those of 1993 (Mo et al 1995). Stensrud (1996) reviewed a number of the previous LLJ studies and also pointed out the important contributions of LLJs to regional climate.…”

Section: Introductionmentioning

confidence: 99%

Low-Level Jets over the Mid-Atlantic States: Warm-Season Climatology and a Case Study

Zhang

Weaver

2006

Journal of Applied Meteorology and Climatology

View full text Add to dashboard Cite

Although considerable research has been conducted to study the characteristics of the low-level jets (LLJs) over the Great Plains states, little is known about the development of LLJs over the Mid-Atlantic states. In this study, the Mid-Atlantic LLJ and its associated characteristics during the warm seasons of 2001 and 2002 are documented with both the wind profiler data and the daily real-time model forecast products. A case study with three model sensitivity simulations is performed to gain insight into the three-dimensional structures and evolution of an LLJ and the mechanisms by which it developed. It is found that the Mid-Atlantic LLJ, ranging from 8 to 23 m s Ϫ1, appeared at an average altitude of 670 m and on 15-25 days of each month. About 90% of the 160 observed LLJ events occurred between 0000 and 0600 LST, and about 60% had southerly to westerly directions. Statistically, the real-time forecasts capture most of the LLJ events with nearly the right timing, intensity, and altitude, although individual forecasts may not correspond to those observed. For a selected southwesterly LLJ case, both the observations and the control simulation exhibit a pronounced diurnal cycle of horizontal winds in the lowest 1.5 km. The simulation shows that the Appalachian Mountains tend to produce a sloping mixed layer with northeasterly thermal winds during the daytime and reversed thermal winds after midnight. With additional thermal contrast effects associated with the Chesapeake Bay and the Atlantic Ocean, the daytime low-level winds vary significantly from the east coast to the mountainous regions. The LLJ after midnight tends to be peaked preferentially around 77.5°W near the middle portion of the sloping terrain, and it decreases eastward as a result of the opposite thermal gradient across the coastline from the mountain-generated thermal gradient. Although the Mid-Atlantic LLJ is much weaker and less extensive than that over the Great Plains states, it has a width of 300-400 km (to its half-peak value) and a length scale of more than 1500 km, following closely the orientation of the Appalachians. Sensitivity simulations show that eliminating the surface heat fluxes produces the most significant impact on the development of the LLJ, then topography and the land-sea contrast, with its area-averaged intensity reduced from 12 m s Ϫ1 to about 6, 9, and 10 m s Ϫ1, respectively.

show abstract

“…Still others have emphasized synoptic scale perturbations such as strong lee troughing east of the Rocky Mountains [Mo et al, 1995].…”

mentioning

confidence: 99%