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Briefing for Weather Forecast for KOKC (Oklahoma City, OK) on Wednesday , April 16 th 2014. Rachel Antone METR 104 Tuesday, April 15 th , 2014. 0. Overview of Current Weather Conditions. visible and infrared satellite images a composite surface weather map
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Briefing for Weather Forecast for KOKC(Oklahoma City, OK)on Wednesday, April 16th 2014 Rachel Antone METR 104 Tuesday, April 15th, 2014
0. Overview of Current Weather Conditions • visible and infrared satellite images • a composite surface weather map • a composite map of conditions aloft • a jet stream map
Forecast Discussion • 18z wind speed and direction: One tactic is to consult the NWS point forecast, which provides wind speed forecasts between 6 am and 6 pm and between 6 pm and 6 am local time. Although, the weakness of this tactic is that the forecast isn’t specific enough for the particular 18z time that we are trying to find the wind speed for. Also the NWS wind speed forecasts in miles per hour so you have to convert into nautical miles or knots, which is 15% larger unit of speed than a mile per hour. To convert miles per hour to knots, you have to divide the speed in miles per hour by 1.15. That's equivalent to reducing the number by about 13%. But the strength is how it gives a more precise location of where the forecast is being taken. • NWS 20 to 30 miles per hour. 25/1.15= 21.73 Second tactic is to use the NWS computer model forecast for winds near the earth's surface. Computer models divide the atmosphere into many discrete "cells" and calculate single, forecast values of temperature, pressure, water vapor content, wind speed, wind direction, etc. in each cell. The cells are 25 miles across that they fail to capture much of the terrain, ground cover, etc. so it isn’t as precise detail to which they will have an effect on local weather conditions; although Oklahoma area isn’t as varied so it won’t be much of a difference. Also the computer model is more precise in time, not just an overview over a period of 12 hours like the NWS. Lastly, The computer model's surface wind forecast shows winds at the center of each regularly spaced cell. So its weakness although precise in time, the area to cover is large making it not as precise for location. NWS computer model about 25 knots • Wind speed is “correct” within plus or minus 5 knots at Iowa State
7. What will the wind speed and direction beat 18Z tomorrow? Links:Latest NWS Point Forecast: Wednesday April 16th: Mostly sunny, with a high near 68. Windy, with a south wind 20 to 30 mph, with gusts as high as 41 mph.
7. What will the wind speed and direction beat 18Z tomorrow? (NAM) forecast of winds andtemperatures at 18Z tomorrow (southern Plains region)
Latest computer model (NAM) forecast of winds and temperaturesat 18Z tomorrow (central Oklahoma region)
Forecast: 24 knots, south wind Forecast Verification: correct if plus or minus 5 knots at Iowa state for wind at 18z and correct if within one octant on either side of the observed wind direction at 18Z NWS weather history 16 12:52 S 32 G 4110.00 Partly Cloudy and Windy SCT 250 SCT300 6427 654625%NANA29.921012.8