Given such values, the National Weather Service will often issue a Wind Chill Advisory so that people can adequately prepare for the elements. This apparent temperature is the Wind Chill Index, and it can be dangerous as values approach 0 degrees. ![]() On a 30 degree afternoon, if there is a 20 mph sustained wind, it feels like 17 degrees to exposed skin. ![]() Have you noticed that it feels colder on a winter day when the wind is blowing? This is not your imagination. Given a temperature, the wind chill index will decrease as the wind strengthens. In the table: The wind chill index is determined by combining the temperature and wind speed. If the edge of the bowl extends all the way into the clouds, and no warm layer exists, then melting would not occur and here comes the snow! This is a typical ice (freezing rain or sleet) scenario. If temperatures are above freezing over the bowl, and there is precipitation falling, there will likely be melting followed by refreezing. Think of it as an upside down bowl of subfreezing conditions, and we are toward the southern edge of the bowl. When cold air dives southward from Canada, it is usually shallow by the time it reaches us. Readings were below freezing near the ground (below 1000 feet), and this led to an ice storm.įorecasting precipitation types in Arkansas is challenging. On that day, temperatures aloft (between 10 feet) were in the 40s, and this melted snowflakes. Sleet and freezing rain are found somewhere in-between, which was the case on. Clouds and precipitation often result, with snow where cold air is deepest, and rain where it is shallow. In the pictures: In Arkansas, it is not uncommon for subfreezing conditions to arrive from the north, and then warm/moist air tries to build into the state from the Gulf Coast before the cold air retreats. Winter Precipitation Types | Example of an Icy Episode () Tree damage was extensive, and at least 30,000 power poles were downed or snapped. More than 300,000 utility customers lost power. The last time it snowed (more than a trace) in the city on Christmas was 1926! In late January, 2009, one to two inches of freezing rain (and locally more) accrued on trees and power lines in roughly the northern two rows of counties. At Little Rock (Pulaski County), 10.3 inches of snow piled up. On Christmas in 2012, much of the region was buried under a thick blanket of heavy snow, with accumulations over a foot in some areas. Major winter events have affected Arkansas in recent years. If cold air arrives, and sticks around as moisture increases, that is when big snow or ice storms often unfold. Most winters in Arkansas feature temperatures that fluctuate (sometimes wildly) and periodic rounds of precipitation. Highway 167 to the south of Cave City (Sharp County), there was ice on the lines and some snow on the ground on. Since early 2012, La Niña has largely been infrequent and weak. There was also record flooding along the Black and lower White Rivers.ĭuring several of these historic events, La Niña was strong (water temperatures were more than 1.5☌ below normal). In April and May, an astonishing 67 (of the yearly total of 75) tornadoes were counted. Finally, one to two feet of snow buried the Ozark Mountains in February of 2011. Another devastating ice storm hit the north in January of 2009. This was a record long track in the state. In February of 2008, a tornado tracked 122 miles through seven counties in the north and west. In December of 2000, two crippling ice storms occurred, and remain one of the largest natural disasters in state history. With La Niña in control, the largest tornado outbreak in Arkansas took place in January of 1999. Interestingly, the most recent huge episodes of snow, ice, and severe thunderstorms occurred when La Niña conditions were dominant, or when water temperatures near the equator in the Pacific Ocean were colder than normal. In the coming months, the pendulum will swing toward La Niña, which favors warmer and drier conditions across much of the southern United States this winter. If warming occurs, then it's El Niño. Both variables have a say in how the weather behaves across the country, especially when they become dominant. If the water cools, we trend toward La Niña. One of the most reliable long-range predictors deals with monitoring water temperatures along the equator in the Pacific Ocean. The graphics are courtesy of the Climate Prediction Center and the International Research Institute for Climate and Society/Columbia University. A moderate La Niña (cooler than normal water by around 1.0☌ along the equator in the Pacific Ocean) increases the chances of extreme weather in Arkansas, including severe thunderstorms and tornadoes. In the pictures: Confidence is highest in a warmer and drier than normal winter (December, 2022 through February, 2023) across much of the southern United States. Temperature Outlook | Precipitation Outlook
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |