ALERT Newsletter – May 2010

Published 05/06/2010 | By KV4S

Hi Everyone, The last few weeks finally saw active weather, which produced callouts. I want to thank all who participated in the callouts. From the feedback I’m getting we did well. For those who where unable to respond, don’t be discouraged. Just keep on keeping on & stand by for the next callout. For others, will surely come & things will finally work out where you can get in on the action. A couple of “housekeeping notes” I’ll pass along. We have had a few requests for access to NWSchat lately from non-ALERT members. To have access you must be a paid up Operational ALERT member, which includes being a currently licensed amateur radio operator, who can respond to callouts. If you are reading this and are not a member, I invite you to join. We welcome you and we need you. For more details visit our website given above. Elections are here! If you are a paid up Operational or Supporting Member (which is a member interested in Amateur Radio, Skywarn or Emergency Communications, but doesn’t have a ham license (yet) you may vote in the 2010 – 2011 ALERT leadership elections. Be sure to attend. </strong> Finally, before we proceed, this newsletter needs some articles. My creative juices sometimes run low, and sometimes dry out. Some might argue that they appear to be in a perpetual drought. So if you have any short articles you can submit, please do so. Thanks in advance! ………………………………………………………………………………………………………………….. Free Weather Stations!!! Would you like a free weather station? How about a whole network of them? Well you are in luck; allow me to introduce you to the realm of Automated Weather and Surface Observation systems. These include AWOS, ASOS, AWSS and ATIS stations. Lets look at them one by one. Automated Weather Observing System (AWOS) – AWOS stations are operated by the Federal Aviation Administration, state & local governments and some private agencies. The NWS and Department of Defense play no part in the deployment or operation of these stations. These are the oldest automated weather systems. Automated Surface Observing System (ASOS) – ASOS stations are operated cooperatively by yhe NWS, FAA & DOD. This is a primary climatological observing network. Deployment of the system began in 1991 and was completed in 2004. Automated Weather Sensor System (AWSS) – These units are operated independently by the FAA & are similar to ASOS stations. Automated Terminal Information Service (ATIS) – These are continous broadcasts of recorded airport information, featuring weather & NOTAMS or Notices To Airmen which can include airport facility notices, nearby bird activity (also called BIRDTAMS), temporary obsticles such as cranes, unlit towers, etc. These generally update every hour and are given a phonetic letter designation starting with “alpha” each day. All of these stations use a similar format for reports. “Birmingham Airport Automated Weather Observation. One six five three zulu. Wind 180 degrees at 7 gusting to 20. Visibility 7. Light rain, mist. Sky condition 700 scattered, 1700 broken, 3500 overcast. Temperature 29 Celsius, Dew Point 12 Celsius. Altimeter 29.64. Remarks distant lightning South West through west. Wind variable between 230 and 150.” These reports are very useful in getting an idea of the conditions both now and just upstream of you. I have them programmed in my phone. The local numbers and frequencies being. Alabaster / Shelby County 205-663-5881 134.325 MHz Bessemer / Jefferson County 205-424-3127 118.825 MHz Birmingham / Jefferson County 205-591-6172 119.400 MHz The following link gives you all of the AWOS and ASOS Frequencies and Telephone by city or airport for Alabama and Mississippi. http://www.faa.gov/air_traffic/weather/asos/?state=AL http://www.faa.gov/air_traffic/weather/asos/?state=MS Now there are a few drawbacks to these stations:

The weather given is the weather where the station is located, and does not necessarily agree with the weather where you are. I remember during an SET where K4NWS was giving wind directions during a simulated chemical spill 10 miles away & having some souls complain that what I was reporting was not what they were seeing. Just as the NWS can’t observe weather conditions at ground level 10 miles away, neither can a single weather station. Truth be known, if you have two identical stations within visual range of each other, they may not necessarily give the same readings. Wind currents and eddies, trees, shadows, unknown or unseen elements all of which make up the microclimate of the location will throw curve balls into the readings.

Cloud layer altitudes are interesting to know. But, they are measured using a laser beam ceilometer that shoots a laser beam straight up & measures return “echo”. This bugger is good and accurate, but has tunnel vision. I have seen times it would say “clear” and it was really ringing a doughnut hole in an otherwise overcast sky. This device has a maximum range of 12000 feet. Low Altocumuli can be detected; higher altocumulus levels will be missed.

Now the Birmingham Airport ATIS which is manually done with a real person reading the observation, unlike in years past when they would give a complete observation, will just say “ceiling better than five thousand five”. Apparently not giving much of a rip as to giving more detail as they might run the risk of missing the Simpsons by taking the time to so. These are not the NWS folk doing this, by the way. I don’t want to get fired. Just label this as Mark’s gripe #572.

Weird observations can come in. Once, way back in the late 70’s the automated system at the Birmingham airport kept saying the temperature was 129 degrees. They finally sent someone out to see why and found a semi sitting there unloading and the exhaust plume of the truck cooking the thermometer.

The heathen communists apparently having won, the temperatures readings are now given in Celsius, instead of Fahrenheit, like the Good Lord intended. So keep a conversion chart handy.

Another resource I find useful or interesting, me being a weatherholic, is the HIWAS or Hazardous In-flight Weather Advisory Service. This is a continuous broadcast of a summary of hazardous weather information including AIRMETS, SIGMETS & PIREPS. AIRMETs – Airmen’s Meteorological Information – which is a description of the occurrences or expected occurrences of en route weather phenomena which may affect the safety of flight operations. SIGMETs – Significant Meteorological Information – which is an advisory containing weather information concerning the safety of all aircraft These may be Convective SIGMET’s or Non-Convective SIGMET’s. Non-convective SIGMET’s are issued when there is severe or greater turbulance over a 3,000 square-mile area, or severe or greater icing over a 3,000 square-mile area or blind flying conditions over a 3,000 square-mile area due to dust, sand or volcanic ash. Convective SIGMET’s are issued for thunderstorm activity over the Continental U.S, aka CONUS. These are issued for an area of thunderstorms affecting an area of 3,000 square-miles or greater, a line of thunderstorms at least 60 nautical miles long, and/or severe or embedded thunderstorms affecting any area that are expected to last 30 minutes or longer. Thunderstorm line length, width, storm height, wind speed, projected hail size, direction of travel and forward velocity are given. A SIGMET forecast is valid for up to four hours and are are assigned an alpha numeric designator from November through Yankee, excluding S and T. Last but not least PIREPS or Pilot Reports of actual significant weather conditions encountered inflight. This information is available on 114.400 MHz, transmitted by the “Vulcan” Visual Omnirange Station or VOR. You have to be just Northwest of Birmingham to pick it up, or on a high elevation. I’ve looked, but not yet found the text product that they read from an online source. There also is a weather station on 162.550 MHz that’s pretty good. I think it’s run by some guy named Noah. ……………………………………………………………………………………………………………………………. Mark’s Almanac May is the fifth month & third month of the Roman calendar. Since ancient times the first day of the month, “May Day” has been a time of celebration. In Rome it honored Flora, the goddess of flowers. It isn’t celebrated as much as it once was in the United States, but I, being older than dirt, remember Maypoles, festivals & such. On May the fifth Mexican’s celebrate Cinco De Mayo, the Celebration of Mayonnaise. Or perhaps celebrating Mexico’s 1862 victory over Napoleon III’s forces at Puebla. Take your pick. Rainfall decreases in May as the Bermuda High strengthens & begins rerouting storm systems northward. The door opens to the Gulf of Mexico & Gulf moisture spreads northward over the continent. The center of maximum tornadic activity also shifts northward over the Nation’s Heartland. May is the peak tornado month, with a 42% increase over April’s amount. For 2010 as of May 3, nationwide there have been 298 tornadoes reported. Alabama is fifth in the nation in tornado touchdowns. Current standings being:
Mississippi 49
Arkansas 33 Texas 32 Missouri 26 Alabama 24 Eastern Pacific hurricane season begins May 15, and although the North Atlantic hurricane season has not arrived, occasionally a tropical system will form in the Gulf of Mexico. In 110 years there have been 14 named storms. May’s Full Moon is “Flower Moon” in Native American folklore. ………………………………………………………………………………………. This month’s meeting will be on May 11 at 7PM at the National Weather Service Forecast office at the Shelby County Airport. I hope to see you there! Mark / WD4NYL President ALERT www.freewebs.com/weatherlynx/
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Posted in ALERT Newsletter