The following content was provided by meteorologist Gail Martell of MartellCropProjections.com:
Intense Cold Wave in Midwest
Intense cold in the American Midwest, drought in California and unseasonable warmth in Europe are due to high amplitude waves in the jet stream.
A bitter cold wave is under way this morning in the United States producing temperatures of -11 F in southern Illinois and Indiana and -25 F in Minnesota and North Dakota. A deep trough in the jet stream is responsible for the bitter cold. Wind chills of -30 to -35 F have forced school and business closings across the Upper Midwest with the coldest temperatures since 1988, according to the National Climatic Data Center.
Six to eight inches of snow preceded the cold wave developing in a wide swath of the Midwest from eastern Missouri across northern Illinois into Indiana . At Chicago's O'Hare International Airport some 1,200 of flights have already been canceled.
Midwest temperatures are expected to moderate later this week increasing by 30 degrees from the present cold. Maximum temperatures Thursday, January 9, would range from teens F in North Dakota to low-mid 30s F in a swath from Kansas through Indiana. Warming temperatures would ease heating oil and natural gas consumption.
Precipitation has been very heavy in the Eastern United States this winter to date. Recurring strong storms, mostly rain, have developed along an unstable frontal boundary, where polar air masses have clashed with mild humid air from the Gulf of Mexico. Up to 150-200% of normal precipitation has developed in the Southeast and Ohio Valley in the past month, causing recurring floods. Still another storm is predicted this week following a similar path from Texas northeastward into the Mid South, central Illinois and Indiana.
Winter weather conditions have been extremely dry in the Western United States. California precipitation in 2013 was a record low in Central valley which is having a very negative impact on agriculture. In the hills near San Jose, the Almaden reservoir serving Silicon Valley is only 3.2% full.
High Amplitude Waves in Jet Stream
A persistent cold trough in the jet stream over the central United States contrasts with a warm ridge along the West Coast. Northeast United States also has experienced a mostly warm winter to date, due to a warm ridge of high pressure aloft, though at times, cold polar air has intruded.
High amplitude waves in the jet stream extend halfway around the world. A cold trough of low pressure in the northeast Atlantic Ocean, offshore from Europe, has prevailed for at least a month. Ahead of the cold trough, a warm ridge of high pressure has built up. This has produced unseasonable mild conditions in Europe. Maximum temperatures this week in northern France are predicted to rise into the mid 50s F, perhaps encouraging slow growth in winter wheat. Wheat grows when the daily average temperature exceeds 41 F.
Unseasonable warmth extends into Ukraine and European Russia where one of the mild winters in years has unfolded. Though temperatures are well above normal, 5-9 F above average, it is still not cold enough to stimulate wheat growth. For example, Ukraine maximum temperatures have reached the mid 30s F in recent days and upper 20s F at night.