The powerful windstorms that swept across the US last week was captured by several different satellites. This type of storm, called a derecho, moved from Illinois to the Mid-Atlantic states on June 29, and the movie from NOAA’s GOES-13 satellite shows the storms’ sudden expansion and speed. The storms left a more than 1,000-km (700-mile) trail of destruction across the Midwest and mid-Atlantic, cutting power to millions and killing thirteen people.
A derecho (pronounced “deh-REY-cho”) is not your average, ordinary local summer thunderstorm. These are widespread, long-lived but rare wind storms that are usually associated with a band of rapidly moving showers or thunderstorms. Damage from a derecho is usually in one direction along a relatively straight track. By definition an event is classified a derecho if the wind damage swath extends more than 400 km (240 miles) and includes wind gusts of at least 93 km/h (58 mph) or greater along most of its length.
These storms occur in the United States during the late spring and summer, with more than three quarters occurring between April and August.
The movie begins on June 28 at 15:15 UTC (11:15 a.m. EDT) and ends on June 30, 2012 at 16:01 UTC (12:01 p.m. EDT). In the animation, the derecho’s clouds appear as a line in the upper Midwest on June 29 at 14:32. By 16:02 UTC, they appear as a rounded area south of Lake Michigan. By 21:32, the area of the derecho’s clouds were near Lake Erie and over Ohio expanding as the system track southeast. By 06:30 UTC, the size appears to have almost doubled as the derecho moves over West Virginia, Maryland, Pennsylvania and Virginia. At 02:32 UTC on June 30 (10:32 p.m. EDT), the Derecho was over the mid-Atlantic bringing a 160 km (100 mile) line of severe storms and wind gusts as high as 144 km/h (90 mph) to the region.
“It is interesting how the process is a self-sustaining process that is fed by a combination of atmospheric factors that all have to be in place at the same time,” said Joe Witte, a meteorologist in Climate Change Communication at George Mason University, Va. and a consultant to NASA. “That is why they are relatively rare: not all the elements line up that often.”
[Its hard not to see the ionic surge of strength added to the normal precipitation front that gives this critter its forward speed and wind strength]
Richard Holle says:
July 3, 2012 at 5:02 pm
Part of the reason for the bow front storms (Derechos) is due to solar wind inductions into the earths magnetic field, and corresponding ion charge potentials between the poles and the equator due to homopolar generator effects. The more energetic the interactions between the suns production in spots and CMEs, (that put out short term surges in magnetic and ion flux,) the more is the effected storm strength and production. When the sun is active the shifts in polarity of the solar wind keep the storms active and spread out, when the magnetic field strength of the earth weakens and becomes stable for periods of time longer than about two weeks, then the polar to equatorial air mass interaction slows down giving rise to larger mid-latitude bands of clean dry air with low ion count. Blocking highs that occur in these areas produce droughts due to there is little precipitable water vapor, and no flux of ions into or out of the area to cause rainfall.
These spots develop low concentrations of ions due to the neutralizing effects of passing fronts, Further poleward you will find Negative ions abound (accounting for the acidic Ph of rain), and closer to the equator positive ions driven off of the ocean surface by wave action nebulization.
When the magnetic fields of the sun and the earth weaken the areas of neutral charged air masses increase in the mid-latitudes, forming into cutoff blocking highs, when surges of ions arrive from the CMEs and solar flares they produce a cascade of free electrons which sweep down on top of the existing Mobile Polar Highs, and show up as intense events due to the ion induced wind power added to the normal temperature gradient across fronts, by these huge surges in free electrons push into the mid-latitudes.
http://www.haarp.alaska.edu/cgi-bin/magnetometer/gak-mag.cgi (graphs of electromagnetic activity of the interactions of the sunspots and CME’s upon the earths atmosphere) you can clearly see the shock impulses these past three days of CME arrival, at the same time the Drecheos were running across the charge boundary as the free electrons came cascading down from the North pole, as long as the graphs show rapid intense fluctuation the higher rate of precipitation results.
So the reason we are having summer droughts, and a lingering dry area in the Texas to South East of USA (for the past couple of years) is due to the decreasing strength of solar magnetic fields, resultant solar wind speed stability, and the probable weakening of the earths “permanent” fields. Thus lowering the ion content in the mid-latitudes allowing these events to occur. Drought until solar induced disruptions cause rapid discharges producing the Derechos along the periphery of the ion null, low aerosol content, zone of dry air in the blocking high pattern.
The maps shown on my site are for the normal average lunar declinational cyclic patterns and surges in ion inductions from solar activity show up as “out of the usual” or I totally miss their presence in my “forecasts for this cycle and I learn what is solar caused and what is not, how the interaction comes down. I learn more about how the electromagnetic interactions between the sun and the planets actually works quantitatively, as well as the length of timing durations to expect.
I built the web site as a learning tool to understand the entire system and its interactions. When I can derive algorithms to adjust the lunar declinational patterns by the expected solar activity, then I will be able to build an active weather forecasting method or model that works much better.