The Arctic Outbreak of 4-8 January 2014 by Richard H. Grumm National Weather Service State College, PA 16803 1. INTRODUCTION An artic outbreak affected much of eastern North American to include the eastern United States from 4-8 January 2014. The cold peaked on 6 January 2014 providing the coldest 24 hour period over the United States in the 21 st Century to date. Relative to previous 20 th Century events, this event was relatively tame and will likely rank near the 40 th coldest day. It trails behind events such as the Christmas Arctic outbreak of December 1983 and the December 1989 outbreak. The most recent comparable, though colder arctic outbreaks occurred in January 1994 and 1996 respectively. The low temperatures observed in January 2014 did not come close to reaching the -70F reading at Rogers Pass, Montana on 20 January 1954 or the Pennsylvania State record of - 42F set at Smethport, PA on 5 January 1904. The cold outbreak affected schools with reports of school closings due to wind chills, set or tied low temperature records, and caused delays at airports from the Dakotas to the East Coast (AP 2014). The cold affected NFL playoff games and lead to rapid ice formation on the Great Lakes which hampered shipping in Lake Erie. The outbreak brought the term polar vortex into the mainstream media. Many locations set new daily low temperature records for the date some of which went back 20 to 126 years 1. This paper will document the pattern and compare it to several previous record events in the eastern United States. In central Pennsylvania the cold episode of record was February 1899. 2. Methods and Data The large scale pattern was reconstructed using the 00-hour forecast of the NCEP Global Forecast System (GFS) as first guess at the verifying pattern. The standardized anomalies were computed in Hart and Grumm (2001). All data were displayed using GrADS (Doty and Kinter 1995). The standardized anomalies and the probability distribution functions are based on the reanalysis climate (R-Climate). Though not shown here, they could be produced from internal model system climatologies (M-Climate). 1 AP report Minneapolis hit -20 tying the record set back in 1888 and New York City tied broke a record set in 1986.
The traditional standardized anomalies were produced from the GFS 00-hour forecast using Climate Forecast System based means and standard deviations. The climatology spans a 30 year period. 3. PATTERN The large scale pattern at 500 hpa (Fig. 1) over the United States in 24-hour increments from 0000 UTC 3 to 8 January 2014 show the polar vortex over southwestern Canada at 0000 UTC 5 January, a trough extending south of these feature was over Minnesota on 6 January which then moved into the Great Lakes by 7 January before lifting back into Canada on the 8 th. The cold air at 850 hpa (Fig. 2) entered the northern Plains on 5 January and the -30C isotherm; often associated with the crème de la crème of arctic air 2 ; was visible across northern Minnesota and North Dakota. As the arctic air moved into the Midwest the standardized anomalies fell to -3σ below normal. Ahead of the arctic air there was a brief surge of warm air over the eastern United States (Fig. 2b-c) and the 850 hpa temperature anomalies peaked at over +2σ above normal in New England. As the arctic air moved over the eastern United States, a -30C contour was observed in the CFSR data as far east as western Pennsylvania (Fig. 2e). The air mass began to lift to the northeast and it warmed considerably over the eastern United States by 0000 UTC 8 January 2013. At the surface (Fig. 3) an area of high pressure with +2 to +3σ pressure anomalies was present in the arctic air and a strong cyclone developed in the southern Plains (Fig. 3a) and moved up the arctic front, across the Great Lakes and into northeastern Canada (Fig. 3b-f). The impact of the 48 to 60 hour period of extreme cold caused rapid formation of ice on rivers and produced ice on the Great Lakes. Lake Erie (Fig. 4); a relatively shallow lake; developed a significant ice cover which was visible by satellite by 8 January and the 17150 UTC 9 January visible satellite image clearly showed the extensive ice cover over Lake Erie s and portions of southern Huron, and Saginaw Bay, Michigan. A list of the top 10 coldest dates in central Pennsylvania is provided in Table 1. Table 2 provides a list of several of the colder periods based on COOP data. These data are used to reconstruct several cold outbreaks from the past in the following section. 4. PAST EVENTS The most recent eastern United States arctic episode occurred in January 1996 and January 1994. The 850 hpa temperatures and anomalies during the January 1994 event are shown in Figure 5. Like many historic arctic outbreaks, this event was accompanied by -30 to -36C air at 850 hpa. The core of the cold air passed west and then south of the Great Lakes with -3s 850 hpa 2 Term and value used in the Albany MAP.
temperature anomalies. A contributing factor to the low temperatures associated with this event in the Mid-Atlantic region was a deep snow cover which was not present during the 2014 event. The core of the December 1983 arctic outbreak was associated with -30 to -36C air at 850 hpa (Fig. 6). The largest thermal anomalies pushed farther west and south relative to the events of 2014 and 1994 with a larger pocket of -30C air and -4s temperature anomalies focused over the Mid-Mississippi Valley (Fig. 6c). January 1982 actually had 2 successive arctic outbreaks including 9-11 January (Fig. 7) and 15-18 January 1982 (Fig. 8). The 15-18 January 1982 arctic outbreak had a -42C contour enter the northern Plains (Fig. 8a) and northern New England (Fig. 8d). Over time a -32C contour came over the southern Great Lakes. The earlier outbreak produced a rare -5σ 850 hpa temperature anomaly over southern Illinois at 1200 UTC 10 January where 850 hpa temperatures of 34C covered most of southern Illinois. Two historic events occurred during the cold period January 1982 including the 14 January 1982 Air Florida aircraft crashing into the icy Potomac River due to icing and the frigid AFC Championship game in Cincinnati, Ohio on 10 January 1982. Several other memorable arctic outbreaks include December 1989, which peaked around Christmas in the eastern United States (Fig. 9). Though not shown, the 850 hpa temperature anomalies were -6s below normal along the Gulf Coast at 0000 UTC 24 December 1989 and a rare snow was observed in the southeastern United States on 24 December 1989. Another remarkable aspect of December 1989 was that it was one of the coldest Decembers in the eastern United States but after that arctic outbreak around Christmas, the pattern changed and most of the eastern United States experienced warmer than normal conditions for the remainder of the winter. There was a brief arctic outbreak in the eastern United States on 24-25 December 1980 (Fig. 10) which too was accompanied by -30C air at 850 hpa. The coldest day in State College as 10 February 1899, The 20 th Century Re-analysis data was used to reconstruct the conditions during this cold episode. The 850 hpa temperatures during this event indicated that the between -26 and -28C air moved over the region (Fig. 11) and that this air mass to was accompanied by the polar vortex (Fig. 12). Several record low temperatures were set in February 1899 at State College and the all-time low of -20F for the site was set on 10 February. The 850 hpa temperatures may not be representative due to the sparse data used to reconstruct the vertical structure of the atmosphere. The conditions in 1936 show the same pool of cold air (Fig. 13), though lacking a -30C contour and a deep 500 hpa low (Fig. 14).
5. SUMMARY The first significant arctic outbreak of the 21 st Century affected much of the eastern United States from 4-8 January 2014. For the first time in over a decade 850 hpa temperatures of -30C spread over portions of the eastern United States plunging surface temperatures to near or below previous record lows for the date. Many locations in the core of the arctic air struggled to get to zero Fahrenheit. The cold caused massive closing of schools, froze rivers and streams, and caused rapid formation and expansion of ice on portions the Great Lakes. The pattern which produced the cold included a deep polar vortex which moved into eastern North America and sub -30C air at 850 hpa, marker used to track some of the colder arctic air masses in North America. Intrusions of -30C are relatively rare and intrusions of the even rarer -40C are extremely rare. This event clearly saw a deep penetration of -30C air into the eastern United States. Several 20 th Century arctic outbreaks were presented. Nearly all which were observed since 1979 were associated with -30C or lower 850 hpa temperatures. Events of this nature have dropped off considerably since the mid-1990s and the arctic outbreak of 1994 was one of the last significant outbreaks in recent memory. The outbreak of December 1983 was one of the more significant outbreaks in recent history. The 20 th Century re-analysis data was used to examine some other historical cold outbreaks. These events too were associated with -26 to -28C air at 850 hpa and a deep 500 hpa cyclone or polar vortex. The 1899 and 1934 (Table 1) cold outbreaks are unique in that these are record low temperatures observed in February. Most of the coldest 50 record lows are typically set in late December through January. Several years with record lows in the top 20 were set in February to include 1899, 1934, 1912, 1905, 1979, 1917, 1918, and 1936. The largest outlier was 18 March 1900 when a low of -9F was recorded. The 20 th Century re-analysis data should be used with caution. There was no upper air network until after World War II and satellite observations lagged by another 3 decades. The more modern data sets have more robust data. There may have been some -30C air at 850 hpa in these pre-1948 cases that cannot be reconstructed. Setting record low temperatures at the surface is a complex issue relate to more than the polar vortex and the temperatures at 850 hpa. Snow cover, wind, and antecedent conditions can and do play a significant role in low temperatures and record low temperatures during the winter. For example, the second coldest low temperature in State College occurred in January 1994. In addition to the extremely cold air mass and ideal pattern, a deep snow cover was present and a deep snow cover was present to the north and west. Snow cover and light winds can produce ideal conditions for radiational cooling. This simplistic study did not investigate or try to isolate events were radiational cooling and cover may have contributed to the record low temperatures.
The lack of arctic air in recent years likely has made people unaccustomed to it. There is an acclimation process associated with dealing with cold and extreme cold. If arctic outbreaks continue to become less common, our ability to cope with them will only diminish. Arctic outbreaks have become less frequent as shown in the Tables 1 & 2. The relationship to global warming was not addressed here. However, research and climate simulations suggest that periodic outbreaks of cold will persist through most of the 21 st Century (KodrA et al 2011). 6. Acknowledgements The Albany map for observations and discussions on the storm, storm potential, and snow to liquid issues related to the storm. Greg Carbin, John LaCorte and Charles Ross for climate records and dates. 7. References Doty, B. E., and J. L. Kinter III, 1995: Geophysical data and visualization using GrADS. Visualization Techniques Space and Atmospheric Sciences, E. P. Szuszczewicz and Bredekamp, Eds., NASA, 209 219. Compo, G.P., J.S. Whitaker, P.D. Sardeshmukh, N. Matsui, R.J. Allan, X. Yin, B.E. Gleason, R.S. Vose, G. Rutledge, P. Bessemoulin, S. Brannimann, M. Brunet, R.I. Crouthamel, A.N. Grant, P.Y. Groisman, P.D. Jones, M. Kruk, A.C. Kruger, G.J. Marshall, M. Maugeri, H.Y. Mok,. Nordli, T.F. Ross, R.M. Trigo, X.L. Wang, S.D. Woodruff, and S.J. Worley, 2011: The Twentieth Century Reanalysis Project. Quarterly J. Roy. Meteorol. Soc., 137, 1-28. Compo, G.P., J.S. Whitaker, and P.D. Sardeshmukh, 2006: Feasibility of a 100 year reanalysis using only surface pressure data. Bull. Amer. Met. Soc., 87, 175-190. Grumm, R.H. and R. Hart. 2001: Standardized Anomalies Applied to Significant Cold Season Weather Events: Preliminary Findings. Wea. and Fore., 16,736 754. Hart, R. E., and R. H. Grumm, 2001: Using normalized climatological anomalies to rank synoptic scale events objectively. Mon. Wea. Rev., 129, 2426 2442. Kocin, P. J., and L. W. Uccellini, 2004: Northeast Snowstorms, Volume I: Overview. Meteor. Monogr., Vol. 32, No. 54, Amer. Meteor. Soc., 1-296. Kocin, P. J., and L. W. Uccellini, 1990: Snowstorms along the northeastern Coast of the United States: 1955 to 1985. Meteor. Monogr., No. 44, Amer. Meteor. Soc., 280p.
Kodra, E, K. Steinhueuser, and A.R. Ganguly: 2011: Persisting cold extremes under 21 st Century warming scenarios. Geo. Res. Letters,38,8. Stuart,N.A and R.H. Grumm 2006: Using Wind Anomalies to Forecast East Coast Winter Storms. Wea. and Forecasting, 21,952-968.
http://eyewall.met.psu.edu/rich/cases/06jan2014/patterns/us-hgtprs50000z08jan2014.png Figure 1. Return to text.
Figure 2. As in Figure 1 except for 850 hpa temperatures and anomalies in 12-hour increments from a) 1200 UTC 5 January through f) 0000 UTC 8 January 2014. Return to text.
Figure 3. As in Figure 2 except for CFSR mean sea-level pressure and pressure anomalies. Return to text.
Figure 4. GOES visual image valid at 1715 UTC 9 January 2014 showing ice over Lake Erie, near shore ice in southeastern lake Huron, and ice in Saginaw Bay, Michigan. The yellow arrows show these three areas. Clouds were present over the center of Lake Huron and the shore ice was identified using loops of imagery. Inset show MODIS ice view in southern Pennsylvania along the Susquehanna river. Return to text.
Figure 5. As in Figure 3 except for 850 hpa temperatures from 1200 UTC 14 through 0000 UTC 17 January 1994. Return to text.
Figure 6. As in Figure 5 except for 850 hpa temperatures from 12 23 December to 0000 UTC 26 December 1983. Return to text.
Figure 7. As in Figure 6 except for the successive 24 hour periods of 1200 UTC 8 to 13 January 1982. Return to text.
Figure 8. As in Figure 6 except for the 6 hour periods of 1200 UTC 16 January through 18 January 1982. Return to text.
Figure 9. As in Figure 6 except for the 25 hour periods of 1200 UTC 24 December through 1200 UTC 29 December 1989. Return to text.
Figure 10. As in Figure 6 except for the 24 hour periods of 1200 UTC 24 through 29 December 1980. Return to text.
Figure 11. The 20 th Century reanalysis data showing 850 hpa temperatures (C ) and temperature anomalies in 12 hour increments from a) 0000 UTC 7 February 1899 through i) 0000 UTC 11 February 1899. Return to text.
Figure 12. As in Figure 11 except for the 500 hpa heights and height anomalies. Return to text.
Figure 13. As in Figure 11 except for the period of 0000 UTC 22 through 26 January 1936. Return to text.
Figure 14. As in Figure 13 except for 500 hpa heights. Return to text.
Rank Temperature Date 1-20 2/10/1899 2-18 1/20/1994 3-17 1/21/1985 4-17 1/18/1982 5-17 2/9/1934 6-17 1/14/1912 7-16 1/25/1963 8-16 2/11/1899 9-15 1/22/1985 10-15 1/24/1963 11-15 1/14/1914 12-15 1/5/1904 13-14 1/23/1936 Table 1. List of the coldest low temperatures in State College based on COOP site data. Return to text. Date 23-25 December 1983 22-24 December 1989 18-20 January 1996 9-10 January 1984 31 December 1973-1 January 1974 8-11 February 1899 11-12 January 1994 Table 2. List of some of the coldest periods in the eastern United States based on COOP data. Return to text.