Picking up from yesterday’s blog post about La Nina and the probability of colder than normal weather and above normal snowfall persisting into the spring, it is interesting to note that parts of California had unusually heavy precipitation earlier this winter (not much lately though). Heavy winter precipitation is more common in southern California when there is an El Nino pattern in the Pacific Ocean. In fact, at one point, some climatologists sounded alarm that anthropogenic global warming (AGW) could lead to more devastating storms for California because the El Nino pattern was expected to occur more often and become stronger. This expectation followed the record strong El Nino of 1998. Since then, El Nino’s have not been too strong. More climatologists are now worried about drought conditions instead of excessive storminess.
Still, the heavy storms from earlier this winter, prove that troublesome weather can occur whether El Nino, La Nina, or niether is occurring. In an effort to prepare as effectively as possible a team of researchers have created a computer model to predict the worst possible stormthat could hit California. They have dubbed it the “ARKStorm scenario”. This type of long-lived super storm could produce up to 10 feet of rain in higher elevations and would likely occur once every 100 to 200 years. It doesn’t take a genius to figure out that 10 feet of rain would be devastating to urbanized areas of California. Seeing that the state is bankrupt, I am a little worried that they will not be able to adequately prepare for the next “ARKStorm”.
In order to more accurately forecast such an impending storm, NASA is employing the robotic global hawk airplane to study “rivers in the sky” that transport water vapor from the tropical Pacific toward the west coast. These “rivers” of moist air have had other names in the past such as the “Pineapple Express” – a term referring to the moisture’s origin around Hawaii.
Reading about these studies got me to wondering how big storms could could become in Wisconsin (in regards to rain and snow). We can find some answers in the record books. Here you can find historical precipitation extremes for Wisconsin. I am surprised that the greatest snowfall for one storm is 31 inches and the greatest 24 hour snowfall is only 26 inches. These are certainly huge amounts of snow, however, the way my grandparents talked about winters from last century, you would think that the records would be measured in feet not inches. Based on my knowledge of weather systems and noting the increase in atmospheric moisture in recent years, I think we could reach 40 inches in a single storm. The key would be thundersnow. If a band of thundersnow formed within the larger storm system and remained stationary for 2 or 3 hours, the snow would really pile up. Rates of snowfall in thundersnow can reach 4 inches or more per hour.
No thundersnow in our forecast for the next few days. Instead, it looks like mild weather for the weekend and much of next week. High temps should top 30 on Saturday and remain in the 30s through at least Thursday. Enjoy the warm-up.
Have a pleasant weekend! Meteorologist Justin Loew.
This post was written by jloew on February 11, 2011