Anomalous United States Weather Patterns Accompanying Stratospheric Sudden Warming.
Abstract
Key signatures of tropospheric circulation are investigated for months during which major Stratospheric Sudden Warming (SSW) occurred in the period 1955 to 1980. For the contiguous United States, monthly values of cyclone frequency, storm paths, precipitation and surface temperature are determined for 17 January and February months and compared against the years in which no SSW events occurred. Consistent with studies of energetics which show that the troposphere loses energy to the stratosphere during SSW, cyclone frequency is approximately 22% less during SSW. Also, consistent with a modification of planetary-scale waves during SSW, mean storm tracks are altered. Most notably, the Colorado Low disappears during SSW. Precipitation totals reflect the changes in cyclone behavior. The Ohio River Valley is the most anomalously dry region of an abnormally dry United States during SSW. During February, the southwestern states exhibit anomalously high precipitation totals. Surface temperatures are significantly below normal, especially east of the Rocky Mountains. During January, every state shows below normal temperatures except Nevada. The February SSW mean temperatures are warmer than normal from the Rocky Mountains westward and particularly in the Pacific Northwest. For both months, the anomalous cold center of the United States is located in the Ohio River Valley, with surface temperatures averaging 5.5 to 6.5 deg F below normal during SSW. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- May 01, 1985
- Accession Number
- ADA166371
Entities
People
- Donald A. Douglas
Organizations
- Air Force Institute of Technology