Monthly Long Range Weather Commentary Issued: February 04, 2012 Steven A. Root, CCM, President/CEO sroot@weatherbank.com Severe thunderstorms spawned tornadoes northeast of Birmingham, Alabama on January 23rd, killing two people and injuring over 100 others. Damage was extensive as homes were destroyed, and trees and power lines were downed. By the next day, the National Weather Service confirmed two tornado paths across north central Tuscaloosa County and was working to confirm reports in other regions. The storm also produced tornadoes and dangerous conditions in Arkansas on the 22nd. No deaths were reported in that state. Several powerful storms earlier in the month also affected several states and injured dozens of people, including Texas, North Carolina, Ohio, Tennessee, Indiana, Kentucky, and Mississippi. In total, NOAA's Storm Prediction Center reported 97 preliminary tornado reports across the U.S. for the month, making January 2012 one of the top 10 busiest Januaries, with records dating back to 1950. The average contiguous U.S. temperature in January was 36.3 F, 5.5 F above the 1901 2000 long term average the fourth warmest January on record, and the warmest since 2006. Precipitation, averaged across the nation, was 1.85 inches. This was 0.37 inch below the long term average, with variability between regions. This monthly analysis is based on records dating back to 1895. ABOVE NORMAL temperatures were widespread across the contiguous United States during January. Nine states AZ, KS, MN, MO, NE, ND, OK, SD, and WY had January temperatures ranking among their ten warmest. FL and WA were the only states with temperatures NEAR NORMAL, and no state was COLDER THAN NORMAL.
Many locations across the Northern Plains exceeded all time warm January maximum temperature records during the month, including Minot, North Dakota, which reached 61 F on January 5th. This surpassed the previous record of 59 F for the city, set on January 28th, 1906. In contrast to the contiguous United States being much warmer than average, several towns across Alaska had their coldest average January temperatures on record Nome ( 16.6 F), Bethel ( 17.3 F) McGrath ( 28.5 F), and Bettles ( 35.6 F). Precipitation totals were mixed across the United States during January. The Southern Plains and the Great Lakes were WETTER THAN NORMAL for the month, with Texas having ABOVE NORMAL precipitation for the second month in a row. Texas had not experienced two consecutive months with above average precipitation since January February 2010. BELOW NORMAL precipitation was observed for the Central Plains, where KS had its third driest January, and NE its eighth. The Southeast was also DRIER THAN NORMAL, where Florida had its eighth driest January on record. Many locations along Florida s Atlantic coast, which usually average over 2.5 inches of precipitation during January, had little to no precipitation during the month. Cities across the Northern Plains, Midwest, and Northeast had BELOW NORMAL snowfall during the month a result of warmer and drier than average conditions. According to the Rutgers Global Snow Lab, the average snow extent during January was 1.0 million square miles, which was 329,000 square miles BELOW the 1981 2010 average. This marks the 3rd smallest January snow cover extent in the 46 year period of record. According to the U.S. Drought Monitor, as of January 31st, 2012, about 3.3 percent of the contiguous U.S. was experiencing the worst category of drought, called D4 or exceptional drought, about the same as the beginning of the month. However, the percent area of the U.S. experiencing drought of any severity increased from 31.9 percent at the beginning of January to 37.9 percent at the end of the month. Most of the drought expansion occurred across the Upper Midwest and the western states. The United States Climate Extremes Index (USCEI) and Regional Climate Extremes Index (RCEI) are sensitive to extremes in temperature, rainfall, dry streaks, drought, and tropical cyclones on the national and regional scale, respectively. During January, the USCEI was above average, driven by a large extent in warm maximum temperatures. The percent area of the U.S. experiencing extremes in warm maximum temperatures was 56 percent, which is the second highest value on record. Regionally, the West North Central, South, and West regions ranked 3rd or 4th highest for the extent of warm maximum temperature extremes. The first two months of the winter season, December and January, have been much warmer than average for the contiguous United States. This two month period was the fourth WARMEST on record with a season to date temperature 3.8 degrees F ABOVE NORMAL. Much of the warmth was anchored across the northern and eastern United States. Minnesota was record warm for the period, with a temperature 10.1 degrees F ABOVE NORMAL. A total of twenty two states from Montana to Maine had December 2011 January 2012 temperatures ranking among their ten warmest. Despite a large winter storm which impacted the western U.S. during January, much of the region was DRIER THAN NORMAL. CA had its fourth driest December January period, and MT had its sixth. WETTER THAN NORMAL conditions were observed in a string of states from NM to NY, with TX having its eleventh wettest December January period.
The following graphic shows the upper level storm track, measured at approximately 18,000 feet above sea level, averaged for JANUARY 2012:
No wonder why most of the USA had ABOVE NORMAL temperatures during JANUARY 2012, with the main storm track displaced well north (compared to average), as the following graphic shows: As stated above, the percent area of the U.S. experiencing drought of any severity increased from 31.9 percent at the beginning of January to 37.9 percent at the end of the month, as per:
Our long range forecast model did extremely well last month, more than adequately identifying the exaggerated warmth across the mid continent; precipitation forecasts did well also, isolating drier than normal conditions from NM to the Great Lakes, yet under stating moisture across the Pacific NW. These graphics depict our model forecasts for JANUARY 2012 made at the end of DECEMBER 2011: These graphics depict actual conditions occurring in JANUARY 2012:
The following graphics depict JANUARY 2012 departure from normal temperatures compared to those of JANUARY 2011 (this year to last year; LY to TY ): The following graphics depict JANUARY 2012 departure from normal precipitation compared to JANUARY 2011 (this year to last year; LY to TY ): Regional City and State Here are our regional climatic hub center weather station verifications for JANUARY 2012: MO. TEMPS ( F) MO. PRECIP. (ins.) MO. SNOWFALL (ins.) OBS NOR DFN OBS NOR DFN (%) OBS NOR DFN Honolulu HI 74.5 73.2 1.2 0.51 2.36 22% 0.00 0.00 Seattle WA 40.0 41.6 1.6 6.83 5.24 130% 9.60 0.00 106667% Portland OR 40.8 40.9 0.1 6.82 4.79 142% 0.00 0.00 Spokane Intl WA 30.0 28.7 1.3 1.71 1.84 93% 10.40 3.00 347% Pendleton OR 35.1 34.4 0.8 1.54 1.44 107% 2.70 0.00 30000% Santa Rosa CA 46.7 45.7 1.0 6.97 7.61 92% 0.00 0.00 LA Airport CA 58.9 57.0 1.9 1.19 2.90 41% 0.00 0.00 Redding CA 45.5 45.5 0.1 5.82 6.74 86% 0.00 0.00 Sacramento CA 46.8 46.2 0.6 2.43 3.72 65% 0.00 0.00 Fresno CA 48.7 46.4 2.3 1.38 2.17 64% 0.00 0.00 Winnemucca NV 31.3 29.8 1.5 0.75 0.89 84% 5.20 2.00 260% Tonopah NV 35.0 31.4 3.6 0.18 0.58 31% 0.00 2.00 0% Phoenix AZ 58.6 56.3 2.3 0.00 0.93 0% 0.00 0.00 Albuquerque NM 40.0 36.5 3.5 0.40 0.31 129% 0.50 0.00 5556% Salt Lake City UT 32.3 29.0 3.3 1.79 1.24 144% 6.90 3.00 230% Grand Junction CO 31.1 27.7 3.5 0.37 0.62 60% 1.60 2.00 80% NOR = Normal, and DFN = Departure from Normal
Regional City and State MO. TEMPS ( F) MO. PRECIP. (ins.) MO. SNOWFALL (ins.) OBS NOR DFN OBS NOR DFN (%) OBS NOR DFN Great Falls MT 29.2 25.6 3.6 0.30 0.62 48% 5.40 2.00 270% Casper WY 29.1 24.7 4.3 0.83 0.62 134% 9.10 2.00 455% Denver CO 36.5 30.5 6.1 0.50 0.31 161% 4.60 0.00 51111% Grand Forks ND 17.5 7.3 10.2 0.38 0.62 61% 4.00 3.50 114% Rapid City SD 29.5 24.3 5.1 0.31 0.31 100% 1.60 1.00 160% Omaha NE 30.6 22.8 7.8 0.06 0.77 8% 1.10 2.00 55% Kansas City MO 35.3 29.0 6.3 0.06 1.15 5% 0.30 2.00 15% Oklahoma City OK 42.7 37.8 4.9 2.23 1.39 160% 0.00 0.00 Lubbock TX 44.3 39.3 5.0 0.01 0.62 2% 0.00 0.00 Dallas Ft. Worth TX 50.1 45.6 4.5 6.18 2.21 280% 0.00 0.00 San Antonio TX 56.2 51.8 4.5 3.99 1.69 236% 0.00 0.00 Minneapolis MN 23.7 16.2 7.5 0.36 0.81 44% 4.50 4.00 113% Green Bay WI 25.0 17.5 7.5 1.40 1.15 122% 10.70 5.10 210% Detroit MI 31.0 25.2 5.8 3.59 2.17 165% 9.20 5.50 167% Regional City and State MO. TEMPS ( F) MO. PRECIP. (ins.) MO. SNOWFALL (ins.) OBS NOR DFN OBS NOR DFN (%) OBS NOR DFN Buffalo NY 30.9 25.7 5.2 4.57 3.11 147% 20.80 6.00 347% Burlington VT 24.9 19.4 5.5 2.27 2.14 106% 13.00 9.50 137% Boston MA 34.1 29.5 4.5 4.77 3.41 140% 6.80 2.40 283% Pittsburgh PA 32.9 28.6 4.3 4.04 2.65 152% 15.80 6.00 263% Philadelphia PA 37.9 32.8 5.2 2.59 2.93 88% 2.50 4.30 58% Baltimore MD 38.6 33.3 5.3 2.54 2.99 85% 1.30 3.00 43% Chicago O'Hare IL 30.8 23.8 7.0 1.86 1.86 100% 11.80 5.00 236% Indianapolis IN 33.6 28.2 5.4 3.64 2.60 140% 3.00 5.80 52% Louisville KY 38.9 34.5 4.4 4.75 3.21 148% 1.80 1.30 138% New Orleans LA 60.6 53.2 7.5 1.81 5.63 32% 0.00 0.00 Raleigh Durham NC 45.8 39.8 6.0 1.96 3.39 58% 0.00 0.00 Wilmington NC 50.4 45.4 5.0 1.77 3.72 48% 0.00 0.00 Atlanta GA 49.0 43.1 5.9 5.14 4.36 118% 0.00 0.00 Tallahassee FL 54.5 50.7 3.7 2.85 4.67 61% 0.00 0.00 Orlando FL 60.1 59.5 0.6 0.13 2.30 6% 0.00 0.00 NOR = Normal, and DFN = Departure from Normal
MO. TEMPS ( F) MO. PRECIP. (ins.) MO. SNOWFALL (ins.) DFN OBS NOR DFN OBS NOR (%) OBS NOR DFN Prince George BC 20.1 18.4 1.8 2.17 1.74 125% 6.90 5.20 133% Edmonton AB 16.5 10.4 6.1 0.64 0.76 84% 5.80 4.00 145% Saskatoon SK 14.7 4.2 10.5 0.49 0.59 83% 5.20 1.70 306% Winnipeg MB 13.3 2.7 10.6 1.35 0.71 190% 15.50 4.00 388% Kenora ON 11.5 3.5 7.9 2.89 1.00 289% 37.60 6.00 627% Timmins ON 10.0 2.8 7.3 4.22 2.02 209% 37.30 9.90 377% Muskoka ON 21.3 15.4 5.9 3.84 3.61 106% 19.50 17.40 112% Toronto ON 29.5 22.6 6.9 4.08 2.15 190% 6.20 9.80 63% Ottawa ON 16.5 14.0 2.5 2.90 2.30 126% 14.20 10.20 139% Barrow AK 20.0 13.2 6.7 0.28 0.31 90% 5.40 1.00 540% Nome AK 17.6 5.4 23.0 0.19 0.93 20% 3.70 6.00 62% Fairbanks AK 25.6 7.6 18.0 0.88 0.62 142% 9.90 2.00 495% Anchorage AK 3.6 17.3 13.7 0.91 0.73 125% 14.50 4.00 363% Juneau AK 27.1 28.1 1.0 7.70 5.35 144% 14.70 8.70 169% Regional City and State Regional City and State NOR = Normal, and DFN = Departure from Normal MO. TEMPS ( F) MO. PRECIP. (ins.) MO. SNOWFALL (ins.) OBS NOR DFN OBS NOR DFN (%) OBS NOR DFN Continental US 39.2 35.1 4.1 2.34 2.37 99% 3.73 1.87 199% So. Canada 17.1 10.4 6.6 2.51 1.65 152% 16.47 7.58 217% Alaska 6.5 6.0 12.5 1.99 1.59 125% 9.64 4.34 222% Equally Weighted Inputs of All Regional Cities Weak La Niña conditions emerged in early August 2011, and grew to weak/moderate strength during northern autumn 2011. As of mid January 2012, SST anomalies remain in weak to moderate La Niña territory in the central and eastern equatorial Pacific. For December the SST anomaly in the NINO3.4 region was 1.04 C, indicative of weak to moderate La Niña conditions, and for the October December season the anomaly was 1.02 C. The most recent weekly SST anomaly in the NINO3.4 region is 1.0 C, indicating weak to moderate La Niña conditions in the tropical Pacific; this is about the same as the 1.04 C level observed in December. The current La Niña SSTs have continued to be below average, and subsurface temperatures across the equatorial Pacific imply a strong likelihood of maintaining at weak to moderate La Niña conditions in the short term, with a good chance for continuing at approximately the current weak to moderate strength for another month or more before beginning to weaken in late February and March. As of mid January, most of the dynamical and statistical models predict La Niña conditions for the JAN MAR season, with weakening beginning toward the end of that period and continuing into the subsequent seasons in early 2012.
For the JAN MAR season, 92% of the models indicate La Niña conditions, and 8% indicate neutral conditions. For FEB APR, these figures become 77% and 23%, respectively. At lead times of 4 or more months into the future, statistical and dynamical models that incorporate information about the ocean's observed subsurface thermal structure generally exhibit higher predictive skill than those that do not. Among models that do use subsurface temperature information, 70% predict ENSO neutral SSTs for the MAY JUL 2012 season, 25% predict La Niña conditions, and 5% predict El Niño conditions. Caution is advised in interpreting the distribution of model predictions as the actual probabilities. At longer leads, the skill of the models degrades, and skill uncertainty must be convolved with the uncertainties from initial conditions and differing model physics, leading to more climatological probabilities in the long lead ENSO Outlook than might be suggested by the suite of models. Furthermore, the expected skill of one model versus another has not been established using uniform validation procedures, which may cause a difference in the true probability distribution from that taken verbatim from the raw model predictions. Predicted ENSO Values and all (multiple) NWS Model Variance
WeatherBank Forecast In late January, I reviewed all years for seeking matching analogs, and found three groups which I pooled, as follows:
Notice: PRIMARY Team '53, '58, '80, '83, '95, '02, '06; and SECONDARY TEAM '65, '72, '92, '98 then After comparing ALL YEARS with those JAN's best matching JAN 2012, these years: Had a GOOD MATCH: '53, '95, '98, 02, '06 These had a FAIR MATCH: '58, '65, '83, '92 And these had an OKAY/POOR MATCH: '72, '80; As a result, I installed the PRIMARY Team ('53, '80, '83, '95, '02, '06) with equal weights.
Thus our forecast for FEBRUARY and beyond for TEMPERATURE is:
Thus our forecast for FEBRUARY and beyond for PRECIPITATION is:
FEBRUARY 2012 Monthly Temperature Departures FEBRUARY 2012 Monthly Precipitation Departures MARCH 2012 Monthly Temperature Departures MARCH 2012 Monthly Precipitation Departures APRIL 2012 Monthly Temperature Departures APRIL 2012 Monthly Precipitation Departures
WeatherBank s Winter Forecast Forecast Monthly Numerical Ratings for WINTER 2011-2012 (out of 62 past winters from 1950-51): Forecast Made Oct. 2, 2011: o Winter 2011-2012 Full USA: 236,781 HDDs; 57 th Coldest; o Winter 2011-2012 GCS: 67,767 HDDs; 56 th Coldest; (GCS = Gas Consuming States) Forecast Made Oct. 31, 2011: o Winter 2011-2012 Full USA: 251,773 HDDs; 42 nd Coldest; o Winter 2011-2012 GCS: 74,756 HDDs; 33 rd Coldest; (GCS = Gas Consuming States) Forecast Made Dec. 11, 2011: o Winter 2011-2012 Full USA: 240,908 HDDs; 57 TH Coldest; o Winter 2011-2012 GCS: 67,162 HDDs; 60 TH Coldest; (GCS = Gas Consuming States) Forecast Made Jan. 03, 2012: o Winter 2011-2012 Full USA: 238,039 HDDs; 57 TH Coldest; o Winter 2011-2012 GCS: 69,310 HDDs; 56 TH Coldest; (GCS = Gas Consuming States) Forecast Made Feb. 1, 2012: o Winter 2011-2012 Full USA: 233,868 HDDs; 59 TH Coldest; o Winter 2011-2012 GCS: 66,716 HDDs; 58 TH Coldest; (GCS = Gas Consuming States) Winter 2010-2011: 256,166 HDDs; Winter 2009-2010: 245,800 HDDs; Winter 2008-2009: 257,204 HDDs; Winter 2007-2008: 253,625 HDDs; Winter 2006-2007: 246,650 HDDs; 5-Year Winter Average: 251,889 HDDs 10-Year Winter Average: 247,137 HDDs WARMEST WINTER since 1950-1951: 1999-00 225,753 HDDs COLDEST WINTER since 1950-1951: 1978-79 282,056 HDDs
Background Methodology for the WeatherBank LROM Using observed calendar day MAX and MIN temperatures at major cities across North America, WeatherBank generates daily Heating Degree Days (HDDs) and Daily Cooling Degree Days (CDDs). By comparing observations of HDDs in winter and CDDs during summer, one may obtain a real time description of how warm or cold the current season is. Basically, the hotter a location is in summer, or colder in winter, the more degree days that location earns. By adding all degree days from all locations, one can obtain a relative description of the current season. By comparing the current season to the degree days totals for past seasons, one obtains a ranking of the current season. WeatherBank's Long Range Outlook Model (LROM) fundamentally assumes that future weather patterns will be similar to a highly correlating, past weather pattern that was determine by trend mapping. All similar weather trends of the past are compared to the current weather trend, then analyzed using a variety of tests. Global inputs such as MEI, average upper level flow patterns, etc., are also used. Correlation coefficients for each input years are generated, and used to define the relative strength of each year and how that trend could be used in the forecast process. Since mid August 2007, strong correlations have remained between the equally weighted (same calendar 13 week period called current, to the same 13 week period of all past years; no lag applied) time periods of the past.