About the same took place farther east at Altus and Ozark (both in Franklin County), and some poultry houses were roughed up near Branch (Franklin County). A few trees/power lines were blown downed, and power poles were snapped. Farther south, more storms were bearing down on western sections of the state, and arrived in Fort Smith (Sebastian County) between 130 am and 200 am CDT. North/east of the city, at least three weak tornadoes (all rated EF1) were spawned. Trees and power lines were downed all over the city, and power was knocked out to more than 200,000 utility customers. The northernmost storms pounded Tulsa, OK with up to 100 mph gusts by 1230 am CDT on the 18th. After a brief lull, storms redeveloped in southern/eastern sections of the state in the afternoon.Īs the event began, there were two large clusters of storms in Oklahoma. The system triggered a round of strong to severe thunderstorms from the southern Plains into Arkansas during the predawn hours. Since hail can cause the rainfall estimates to be higher than what is actually occurring, steps are taken to prevent these high dBZ values from being converted to rainfall.In the video: Satellite showed a storm system (swirling clouds) tracking from Kansas into Missouri on. Hail is a good reflector of energy and will return very high dBZ values. These values are estimates of the rainfall per hour, updated each volume scan, with rainfall accumulated over time. Depending on the type of weather occurring and the area of the U.S., forecasters use a set of rainrates which are associated to the dBZ values. The higher the dBZ, the stronger the rainrate. Typically, light rain is occurring when the dBZ value reaches 20. The scale of dBZ values is also related to the intensity of rainfall. The value of the dBZ depends upon the mode the radar is in at the time the image was created. Notice the color on each scale remains the same in both operational modes, only the values change. The other scale (near left) represents dBZ values when the radar is in precipitation mode (dBZ values from 5 to 75). One scale (far left) represents dBZ values when the radar is in clear air mode (dBZ values from -28 to +28). Each reflectivity image you see includes one of two color scales. The dBZ values increase as the strength of the signal returned to the radar increases. So, a more convenient number for calculations and comparison, a decibel (or logarithmic) scale (dBZ), is used. Reflectivity (designated by the letter Z) covers a wide range of signals (from very weak to very strong). "Reflectivity" is the amount of transmitted power returned to the radar receiver. The colors are the different echo intensities (reflectivity) measured in dBZ (decibels of Z) during each elevation scan.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |