Friday, July 02, 2010

The Skies Above

Finally, I get a chance to surface for air, having gone to ground while I put time in my shop where I designed and constructed a new multi band HF antenna for my pickup. I had a set of design parameters that I wished to incorporate in to this new multi-band HF antenna, and with the completed antenna now being put through a range of tests, I am pleased with how the antenna has performed to date.
Lately, I have been out on the plains of eastern Alberta as the watch begins with the thunderstorm season now upon us, and as warm air begins to spread across the plains of southern Alberta. This warm air along with a cold front provides fuel for thunderstorms to form up in the late afternoon with the most severe thunderstorms, possibly producing tornadoes that are generally produced by isolated supercells which form along the dry line of a front.
While out on the 564 north and east of Strathmore, I watched as several systems further east formed up, and with my VHF radio set to the frequency of 145.290mhz for the Foothills-Repeater-System, my VHF radio went in to full alarm status and automatically switched to 162.400mhz upon detection of the 1050Hz tone, issued for ten seconds immediately before the warning message started to be broadcast. The first severe-weather-warning that I received was for the County of Wheatland, that included the towns of Standard, Rosebud, Rockyford, and Drumheller. As I drove eastward, I watched the skies ahead of me as a cell was forming nicely with a very well formed anvil on the top at approximately 40,000 feet. I finally caught up to this thunderstorm north of Standard and just to the south of Rosebud.

With the mature stage of the thunderstorm now reached, the warmed air having risen until it reached existing air which was warmer, and the air not able to rise any further had capped out at the tropopause. The air had been forced to spread out, giving the storm the characteristic anvil shape that you probably have witnessed when observing a summer thunderstorm. Now with cumulonimbus incus formed, the water droplets within this cloud began to freeze and became ice particles. I could see white streaks as these water droplets began falling as hail on the fields in the surrounding area of highway 564 and highway 840, and I soon began to experience heavy rain mixed with pea-sized hail. The system was being driven northward towards Rosebud with winds gusting near 80kph as indicated on the display of my roof mounted anemometer. Fortunately this storm weakened quickly and soon left me behind as it worked its way north and east towards the Drumheller Valley and the Hand Hills beyond.

As the skies cleared out behind the storm, I turned for home as I wanted to make a modification to my multiband antenna, having noticed a small hiccup with the tuning sleeve while tuning from 80 meters through to 17 meters. On the way back to Calgary I checked in on the APSN (Alberta Public service net) that is held daily, with Hams across Alberta, Saskatchewan, and BC checking in. I arrived home in good time with the sun just setting on the western horizon and the skies having cleared out nicely. Before long you can expect to find me out and about once more in search of afternoon thunderstorms.

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