A nice mid to late fall weekend but with an inland frost/light freeze early Sunday & again early Monday. We'll experience the coldest nighttime temps. since Feb. in many places. Still no significant rain through the upcoming week with only a few sprinkles or very light showers Tue. night.
Earth Gauge: Thanksgiving Travel
According to AAA, more than 43 million Americans will journey 50 miles or more from home over the Thanksgiving holiday weekend – and 90 percent will travel by car. Increased traveling distance and unpredictable weather can result in hazardous driving conditions at this time of year. Here, get tips for safe and efficient travel, whether your destination is near or far.
Stay Safe on the Roads
· Get a check-up. Check tire pressure when tires are cold and adjust as necessary (don't forget the spare!), replace worn or broken wiper blades, add freeze-resistant windshield wiper fluid if needed, and check battery connections and cables. If your car battery is more than three years old, you may want a professional to test it.
· Build an emergency kit. Make sure your car is equipped with a scraper, flashlight, blankets, cell phones, booster cables and emergency flares or cones. Have water and non-perishable food like energy or granola bars on hand, too.
· Slow down. Allow yourself at least eight to ten seconds of stopping time – even longer if driving on ice.
· Stop before you talk. If you need to use your cell phone, pull into a parking area or to the side of the road before making the call.
· Be ready for rain. During periods of heavy rain, reduce your speed and put on your car’s hazard lights so that other drivers can see you more easily. If it is difficult to see through heavy rain, pull over and wait for the storm to pass.
· Carpool. The average distance traveled over Thanksgiving is 588 miles. If you have friends and family nearby that are going to the same place, travel together to save gas and reduce the number of cars on the road.
· Go easy on the gas pedal. Accelerate gradually to get better gas mileage.
· Don’t idle. If you stop to eat or stretch your legs, turn the car completely off. Idling for two minutes uses the same amount of gas used to drive one mile!
· Pack lightly. Extra weight in the car or trunk decreases fuel efficiency.
(Sources: AAA. "2012 AAA Thanksgiving Holiday Travel Forecast", "Five Things AAA Says Drivers Should Do Before Thanksgiving Road Trips."; Research and Innovative Technology Administration. “U.S. Holiday Travel.”; Iowa DOT. “Safe-driving tips for the holidays.” Environmental Protection Agency. “Tips to Save Gas and Improve Mileage.”; Green Your. “Avoid Car Idling.”)
Climate Fact: 17th Century Climate in the Northeast
In Brief: Cooler temperatures, fewer hurricanes and an expansion of red spruce across the Northeast region characterized the climate the Pilgrims encountered when they landed 400 years ago.
Back in the 17th century when the Pilgrims landed, average temperatures in the Northeast United States were as much as 3.5 degrees Fahrenheit cooler than today. This was dramatic compared to the cooling most of the rest of the Earth experienced during the Little Ice Age (LIA), which ran from 1400 CE until about 1800 CE. The average temperature of the Northern Hemisphere during the LIA, for example, was about one degree Fahrenheit cooler than today. The precise mechanisms behind the LIA cooling are not completely understood, with volcanic activity, changes in solar activity and long-term variations in ocean heat distributions all likely playing some role. Some clear features of this period that would have affected the Northeast in the 1620s include:
· Winds of the North Atlantic: The strength of the westerly winds blowing across the North Atlantic reflect the degree of winter storminess and inversely the degree to which cold Arctic air masses can invade midlatitude regions like the Northeast (see useful climate analogy: The Arctic Oscillation and Your Refrigerator Door). During the LIA, these winds were likely weaker overall compared to today and Arctic air masses invaded the Northeast more frequently. Cyclonic winter storms that are spawned by the temperature and moisture differences between the Gulf Stream and North Atlantic waters were likely less common yet more intense when they did happen.
· Ocean Stratification and Decreased Hurricane Activity: Hurricane records from a lake near Boston suggest that while up to eight extreme hurricanes (Categories 3 or higher on Saffir-Simpson scale) struck during the 12th and 16th centuries, only about two or three extreme hurricanes struck during the 17th century. The cooler North Atlantic ocean SSTs during this period coupled with what were likely predominant El Niño conditions in the tropical Pacific Ocean worked together to reduce hurricane activity in the North Atlantic. In contrast, the warm North Atlantic ocean and La Niña conditions in the tropical Pacific during the Medieval Warm Period (MWP) from 1000-1300 probably meant more North Atlantic hurricanes during that time. Related to both the North Atlantic winds and the North Atlantic sea surface temperatures is the strength of the basin’s northward movement of warm water and returning southward movement of cool water, the Atlantic Meridional Overturning Circulation (AMOC). The strength of the AMOC is also affected by the shift between El Niño/La Niña conditions in the tropical Pacific.
· Forest Structure and Vegetation: The Northeast that the Pilgrims encountered 400 years ago featured now gone expanses of towering, old-growth forests with the fruitful American Chestnut being the dominant tree. The Northeast in the 1620s was a mixture of large tracts of this old-growth forest, lands being used by Native Americans to grow crops and also a fair amount of younger forests growing on lands that had been left vacant as newly introduced Eurasian viruses decimated Native American populations during the 1500s. Across the landscape, as temperatures were cooling following the MWP, the conifer species red spruce began to move south from New England and from higher elevations to lower elevations elsewhere in the Northeast. They replaced trees that do better with warmer temperatures such as yellow birch, sugar maple and American beech. Since 1900, as temperatures have warmed, red spruce has become less common in the region.
(Sources: Houle, D et al. “Compositional vegetation changes and increased red spruce abundance during the Little Ice Age in a sugar maple forest of north-eastern North America.” Plant Ecology 213 (2012): 1027-1035 and Sorrell, P et al. “Persistent non-solar forcing of Holocene storm dynamics in coastal sedimentary archives.” Nature Geoscience. Published Online 11 November 2012. Accessed Online 19 November 2012: and Darby, DA et al. “1,500-year cycle in the Arctic Oscillation identified in Holocene Arctic sea-ice drift.” Nature Geoscience. Published Online 11 November 2012. Accessed Online 19 November 2012: and Power, MJ et al. “Climatic control of the biomass-burning decline in the Americas after AD 1500.” The Holocene (2012): 1-11 and Trouet, V et al. “North Atlantic storminess and Atlantic Meridional Overturning Circulation during the last Millennium: Reconciling contradictory proxy records of NAO variability.” Global and Planetary Change 84-85 (2012): 48-55 and Nott, J. “Tropical cyclones, global climate change and the role of Quaternary studies.” Journal of Quaternary Science 26 (2011): 468-473 and Woodruff, JD et al. “Tropical cyclone activity and western North Atlantic stratification over the last millennium: a comparative review with viable connections.” Journal of Quaternary Science 27 (2012): 337-343 and Oswald, WW and Foster, DR. “A record of late-Holocene environmental change from southern New England, USA.” Quaternary Research 76 (2011): 314-381 and Li, YX et al. “Sensitive moisture response to Holocene millennial-scale climate variations in the Mid-Atlantic region, USA.” The Holocene 17 (2007): 3-8 and Olsen, J et al. “Variability of the North Atlantic Oscillation over the past 5,200 years.” Nature Geoscience. Published Online 23 September 2012. Accessed Online 19 November 2012 and Houle, D et al. “Ice Bridges on the St. Lawrence River as an Index of Winter Severity from 1620 to 1910.” Journal of Climate 20 (2007): 757-764 and Besonen, MR et al. “A 1,000-year, annually-resolved record of hurricane activity from Boston, Massachusetts.” Geophysical Research Letters 35 (2008): L14705.)
Have a great & safe weekend!