Influence of the Madden–Julian Oscillation on Summertime Cloud-to-Ground Lightning Activity over the Continental United States

2009 ◽  
Vol 137 (10) ◽  
pp. 3596-3601 ◽  
Author(s):  
John T. Abatzoglou ◽  
Timothy J. Brown
Keyword(s):  
United States ◽  
Great Basin ◽  
Lightning Activity ◽  
Western United States ◽  
Madden Julian Oscillation ◽  
Lightning Strikes ◽  
Northern Rocky Mountains ◽  
Seasonally Dry ◽  
Desert Southwest ◽  
Cloud To Ground Lightning

Abstract Summertime cloud-to-ground lightning strikes are responsible for the majority of wildfire ignitions across vast sections of the seasonally dry western United States. In this study, a strong connection between active phases of the Madden–Julian oscillation (MJO) and regional summertime lightning activity was found across the interior western United States. This intraseasonal mode of lightning activity emanates northward from the desert Southwest across the Great Basin and into the northern Rocky Mountains. The MJO is shown to provide favorable conditions for the northward propagation of widespread lightning activity through the amplification of the upper-level ridge over the western United States and the development of midtropospheric instability. Given the relative predictability of the MJO with long lead times, results allude to the potential for intraseasonal predictability of lightning activity and proactive fire management planning.

scholarly journals Model-Generated Predictions of Dry Thunderstorm Potential

2007 ◽  
Vol 46 (5) ◽  
pp. 605-614 ◽  
Author(s):  
Miriam L. Rorig ◽  
Steven J. McKay ◽  
Sue A. Ferguson ◽  
Paul Werth
Keyword(s):  
United States ◽  
Mesoscale Model ◽  
Western United States ◽  
State University ◽  
Lightning Strikes ◽  
Convective Storms ◽  
Interagency Coordination ◽  
Fifth Generation ◽  
Cloud To Ground Lightning ◽  
Fire Ignitions

Abstract Dry thunderstorms (those that occur without significant rainfall at the ground) are common in the interior western United States. Moisture drawn into the area from the Gulfs of Mexico and California is sufficient to form high-based thunderstorms. Rain often evaporates before reaching the ground, and cloud-to-ground lightning generated by these storms strikes dry fuels. Fire weather forecasters at the National Weather Service and the National Interagency Coordination Center try to anticipate days with widespread dry thunderstorms because they result in multiple fire ignitions, often in remote areas. The probability of the occurrence of dry thunderstorms that produce fire-igniting lightning strikes was found to be greater on days with high instability and a deficit of moisture at low levels of the atmosphere. Based on these upper-air variables, an algorithm was developed to estimate the potential of dry lightning (lightning that strikes the ground with little or no rainfall at the surface) when convective storms are expected. In the current study, this algorithm has been applied throughout the western United States, with modeled meteorological variables rather than the observed soundings that have previously been used, to develop a predictive scheme for estimating the risk of dry thunderstorms. Predictions of the risk of dry thunderstorms were generated from real-time forecasts using the fifth-generation Pennsylvania State University–National Center for Atmospheric Research Mesoscale Model (MM5) for the summers of 2004 and 2005. During that period, 240 large lightning-caused fires were ignited in the model domain. Of those fires, 40% occurred where the probability of dry lightning was predicted to be equal to or greater than 90% and 58% occurred where the probability was 75% or greater.

scholarly journals on the prevention of lighting

1969 ◽  
Vol 50 (7) ◽  
pp. 514-521 ◽  
Author(s):  
C. D. Stow
Keyword(s):  
United States ◽  
Forest Fires ◽  
Western United States ◽  
Agricultural Crops ◽  
Loss Of Life ◽  
The World ◽  
Lightning Discharges ◽  
Cloud To Ground Lightning ◽  
Recreational Resources

The destructive nature of cloud-to-ground lightning strokes is well known. Loss of life and damage to buildings and other man-made structures may to a large extent be prevented by the judicial use of lightning conductors and screens but no comparable protection may be offered to expanses of agricultural crops or forests. According to Fuquay (1967) lightning is the greatest single cause of forest fires in the western United States: during the period 1946–1962, 140,000 such fires occurred causing severe losses of timber, wildlife, watershed, and recreational resources. Comparable losses occur regularly in other parts of the world. The only solution is the suppression or modification of cloud-to-ground lightning discharges. Methods of suppression are described, some of which may turn out to be practical ways of achieving this aim.

scholarly journals Coherence between the Great Salt Lake Level and the Pacific Quasi-Decadal Oscillation

2010 ◽  
Vol 23 (8) ◽  
pp. 2161-2177 ◽  
Author(s):  
Shih-Yu Wang ◽  
Robert R. Gillies ◽  
Jiming Jin ◽  
Lawrence E. Hipps
Keyword(s):  
United States ◽  
Great Basin ◽  
Lake Level ◽  
Salt Lake ◽  
Western United States ◽  
Water Vapor Flux ◽  
Vapor Flux ◽  
The Pacific ◽  
Circulation Patterns ◽  
Precipitation Variation

Abstract The lake level elevation of the Great Salt Lake (GSL), a large closed basin lake in the arid western United States, is characterized by a pronounced quasi-decadal oscillation (QDO). The variation of the GSL elevation is very coherent with the QDO of sea surface temperature anomalies in the tropical central Pacific (also known as the Pacific QDO). However, such coherence denies any direct association between the precipitation in the GSL watershed and the Pacific QDO because, in a given frequency, the precipitation variation always leads the GSL elevation variation. Therefore, the precipitation variation is phase shifted from the Pacific QDO. This study investigates the physical mechanism forming the coherence between the GSL elevation and the Pacific QDO. Pronounced and coherent quasi-decadal signals in precipitation, streamflow, water vapor flux, and drought conditions are found throughout the Great Basin. Recurrent atmospheric circulation patterns develop over the Gulf of Alaska during the warm-to-cool and cool-to-warm transition phases of the Pacific QDO. These circulation patterns modulate the water vapor flux associated with synoptic transient activities over the western United States and, in turn, lead to the QDO in the hydrological cycle of the Great Basin. As the GSL integrates the hydrological responses in the Great Basin, the hydrological QDO is then transferred to the GSL elevation. Because the GSL elevation consistently lags the precipitation by a quarter-phase (about 3 yr in the quasi-decadal time scale), these processes take an average of 6 yr for the GSL elevation to eventually respond to the Pacific QDO. This creates a half-phase delay of the GSL elevation from the Pacific QDO, thereby forming the inverse, yet coherent, relationship between them. Tree-ring reconstructed precipitation records confirm that the quasi-decadal signal in precipitation is a prominent feature in this region.

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