Monthly Long Range Weather Commentary Issued: APRIL 18, 2017 Steven A. Root, CCM, Chief Analytics Officer, Sr. VP, sroot@weatherbank.com MARCH 2017 Climate Highlights The Month in Review The average contiguous U.S. temperature during March was 46.2 F, 4.7 F above the 20th century average, and ranked as the ninth warmest on record. Most of the West, Great Plains and parts of the Midwest and Southeast were warmer than average. Thirteen states were much warmer than average, with Colorado and New Mexico being record warm. The Colorado statewide average temperature was 42.5 F, 8.8 F above average, while the New Mexico temperature was 51.4 F, 7.9 F above average. Near-to below-average temperatures were observed across the Great Lakes and from the Mid-Atlantic to New England. The coldest temperatures, relative to average, were observed across New England. Following the record warm February in the Northeast, some locations had March temperatures that were colder than February an unusual, but not unprecedented occurrence. The Alaska statewide average temperature was 4.1 F, 6.7 F below average. This was the 12th coldest March in the 93- year record for the state and coldest since 2007. This ended Alaska's stretch of 17 consecutive months, beginning in October 2015, of an above-average statewide temperature.
The contiguous U.S. average maximum (daytime) temperature during March was 57.8 F, 4.8 F above the 20th century average, the 11th warmest on record. Above-average maximum temperatures were observed across most of the West, Great Plains, and the Southeast. New Mexico had a record warm maximum temperature for March. Below-average maximum temperatures were observed in the Northwest and the Northeast. The contiguous U.S. average minimum (nighttime) temperature during March was 34.5 F, 4.5 F above the 20th century average, the eighth warmest on record. Above-average minimum temperatures were observed for most locations across the country, with the exception of the East Coast. Much-above-average minimum temperatures were observed in the West and Great Plains where Colorado, Idaho, Utah, and Wyoming had record warm nights. Below-average minimum temperatures were observed in the Northeast. During March there were 5,494 record warm daily high (2,690) and low (2,804) temperature records, which is more than three times the 1,779 record cold daily high (1,168) and low (611) temperature records. Based on NOAA's Residential Energy Demand Temperature Index (REDTI), the contiguous U.S. temperature-related energy demand during March was 27 percent below average and the 24th lowest value in the 123-year period of record. The March precipitation total was 2.56 inches, 0.05 inch above the 20th century average, and ranked near the middle of the 123-year period of record. Locations from the Northwest through the Northern Rockies, Central Plains and Midwest were wetter than average, with Idaho, Oregon and Washington having much-above-average precipitation. The above-average precipitation in the Plains and Midwest was accompanied by severe weather outbreaks including damaging tornadoes. Abundant snowfall earlier in the season from California to the Central Rockies, combined with above-average March precipitation across the Northwest and Northern Rockies, resulted in above-average snowpack at most mountain locations on April 1st. Below-average precipitation was observed in parts of the Southwest, Northern Plains and along the East Coast. Florida and Georgia had much-below-average precipitation during March. Alaska had its fifth driest March on record with 1.16 inches of precipitation, 1.00 inch below average. Record dryness was observed across the southern parts of the state. According to an analysis of NOAA data by the Rutgers Global Snow Lab, the March contiguous U.S. snow cover extent was 660,000 square miles, 81,000 square miles below the 1981-2010 average and the 19th smallest in the 51-year period of record. Above-average snow cover was observed across parts of the Northeast, Mid-west, and Northwest. Below-average snow cover was observed in parts of the Great Basin and the Great Plains. According to the March 28 U.S. Drought Monitor report, 14.2 percent of the contiguous U.S. was in drought, up 0.1 percent compared to the end of February. Drought improved across some areas of the West, Mid-South, and Northeast. Drought conditions expanded on Hawaii's Big Island. Drought conditions also developed and intensified across parts of the Central and Southern Plains and Southeast, where warm, windy and relatively dry conditions increased wildfire danger, with 2 million acres burning during the month. This was nearly seven times the 2000-2010 average and more than 600,000 acres above the previous record set in 2006.
Climate Highlights Year to Date (JAN - MAR) The year-to-date contiguous U.S. average temperature was 40.3 F, 5.1 F above average. This was the second warmest January-March on record, behind the record of 41.4 F set in 2012. Above-average temperatures spanned the nation with only the Northwest being colder than average. Thirty-eight states were much warmer than average during January-March with six states Louisiana, Mississippi, New Mexico, Oklahoma, South Carolina, and Texas record warm. The contiguous U.S. average maximum (daytime) temperature during January-March was 50.9 F, 4.8 F above the 20th century average, the third warmest on record. Only during the January-March periods in 2000 and 2012 were maximum temperatures warmer. Above-average maximum temperatures were observed for most locations from the Rockies to East Coast. Georgia, Oklahoma, and South Carolina had record warm maximum temperatures for the first quarter of 2017. Below-average maximum temperatures were observed in the Northwest. The contiguous U.S. average minimum (nighttime) temperature during January-March was 29.7 F, 5.5 F above the 20th century average, the second only to 2012. Above-average minimum temperatures were observed for most locations across the country, with the exception of the Northwest. Seven states in the Southern Rockies, Southern Plains and Lower-Mississippi Valley had record warm minimum temperatures. Based on REDTI, the contiguous U.S. temperature-related energy demand during January-March was 80 percent below average and the second lowest value in the 123-year period of record. The year-to-date contiguous U.S. precipitation total was 8.09 inches, 1.10 inches above average. This ranked as the 10th wettest January-March on record and wettest since 1998.
Above-average precipitation spanned most of the West into the Great Plains and Great Lakes. Seven Western states, in addition to Michigan, had year-to-date precipitation totals that were much above average. Below-average precipitation was observed for the Mid- and Lower-Mississippi River Valley and along the Southeast Coast. In the first three months of 2017 there have been five weather and climate disaster events with losses exceeding one billion each across the United States. These events included a flooding event, a freeze event, and three severe storm events collectively causing 37 fatalities. The number of billion-dollar events for January-March (5) is the largest number of first-quarter events in the 1980-present period of record and doubles the average number of events for January- March over the last 5 years (2.4 events). The U.S. Climate Extremes Index (USCEI) for the year-to-date was the highest value on record at more than double the average. On the national scale, extremes in warm daytime and nighttime temperatures, one-day precipitation totals, days with precipitation, and the spatial extent of drought were much above average. The USCEI is an index that tracks extremes (falling in the upper or lower 10 percent of the record) in temperature, precipitation and drought across the contiguous United States. Regionally, the CEI was much above average in the Ohio Valley, Southeast, and Southwest. A record high CEI value for the first quarter of 2017 was observed in the Upper Midwest and South. In each of these regions, the spatial extent of extremely warm maximum and minimum temperatures was above average. In the Upper Midwest, the spatial extent of wet conditions was the second highest on record. In the South, one-day precipitation extremes were record high.
Climate Highlights Cold Season (OCT - MAR) The contiguous U.S. average temperature for the cold season was 43.3 F, 4.2 F above average. This was the second warmest October-March on record, only marginally cooler than the record warm cold season that occurred just last year. Above-average temperatures spanned the nation with only the Northwest being colder than average. Forty-three states were much warmer than average during October-March with 12 states across the southern tier, from the Rockies to Florida, being record warm. The contiguous U.S. average maximum (daytime) temperature during October-March was 54.1 F, 4.0 F above the 20th century average, the third warmest on record. Only during the October-March periods in 2000 and 2012 were maximum temperatures warmer. Above-average maximum temperatures were observed for most locations from the Rockies to East Coast, in addition to the Southwest. Twelve states from the Southern Rockies to Florida had a record warm maximum temperature for the cold season. The contiguous U.S. average minimum (nighttime) temperature during October-March was 32.4 F, 4.5 F above the 20th century average, the second only to 2015-16. Above-average minimum temperatures were observed for most locations across the country, with the exception of the Northwest. Eight states in the Southern Rockies, Southern Plains and Lower-Mississippi Valley had record warm minimum temperatures. Based on REDTI, the contiguous U.S. temperature-related energy demand during the cold season was 85 percent below average and the second lowest value in the 122-year period of record. The cold season contiguous U.S. precipitation total was 15.04 inches, 1.34 inches above average. This ranked as the 22nd wettest October-March on record. Above-average precipitation spanned most of the West into the Northern Plains and Great Lakes. Seven Western states had year-to-date precipitation totals that were much above average. Wyoming had its wettest cold season on record with 10.13 inches of precipitation, 3.61 inches above average. This bested 9.92 inches in 1898-99.
Below-average precipitation was observed the Southeast, Mid-Atlantic, and parts of the Midwest. Delaware, Florida, and Maryland had cold-season precipitation totals that were much below average. The U.S. Climate Extremes Index (USCEI) for the cold season was the second highest value on record at nearly 2.5 times the average. On the national scale, extremes in warm daytime and nighttime temperatures, one-day precipitation totals, and the spatial extent of wet conditions were much above average. Regionally, the CEI was much above average for all regions except the Northern Rockies and Plains and the Northeast. Extremes in warm maximum and minimum temperatures contributed to the above-average CEI in the Northeast, Upper Midwest, Ohio Valley, Southeast, South, Southwest, and West. In the Northeast extremes in days with precipitation was above average. In the Upper Midwest, extremes in the spatial extent of we conditions was above average. In the South, extremes in one-day precipitation totals were above average while in the West days with precipitation were above average.
Climate Highlights Soil Moisture Conditions
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Climate Highlights Severe Weather Analysis All Event Distribution March Tornado Event Distribution March
Wind Event Distribution March Hail Event Distribution March
Long Range Analog Analysis
Trend Adjustments Made by S.A. Root --- APR 10, 2017 The current period reviewed was JAN 15 th APR 8 th resulting in these two observations: Looking back at the past 30, 60, 90 and 120-days, we have:
REVIEW of S ROOT s LATE FEB TEMP ANALOGS: 1952, 1999, 2006x4, 2009, and 2012x4: 1952 and 2009 were off trend, yet 1999, 2006 and especially 2012 were quite good and captured the warm trend well REVIEW of SOURCE-2 (PP) TEMP ANALOGS (as of 4/10): 1963x2, 1965, 1991, 2002x3, 2006x2, and 2009:
S ROOT APRIL 10 th NEW ANALOGS for Consideration for Inputs to Analog Trend Mapping:
Here is the statistical correlation, using daily average temperature for regional hub cities, JAN 15 APR 08, 2017 versus all prior years, same period: Now focusing in on the main storm track, the 500 mb flow, averaged from JAN 15 th APR 8 th (left), FEB 15 th APR 8 th (right) and FEB 15 th APR 8 th (bottom), we see a consistent HIGH center over the midcontinent trailing south and west across southern California, and this feature seems to be intensifying:
Here is the Balance of the Month for April which is made up of part OBSERVED data through the 9 th, and predicted data using our high-resolution UFDB model for the 10 th 30 th, followed by May 2017, which is built using nearly 100% of the UFDB model (our analog inputs begin with the 46 th day from today ): Isolating only those past trends where the mid-continent warmth anomaly remained (supported by the 500mb pattern aloft continuing), I have these past analog years:
It is rather interesting to note, that a common feature with 4 of 6 of the above years (and also a number of other analog years failing to make this final cut), is the COOLER than NORMAL west coast/great Basin region After confirming calibrations, I have elected using 1952, 1986, 1999, 2000 x 3, 2006, and 2012 x 3, which result in the following outlooks (first, the calibrations for APRIL and MAY again which use 100% UFDB): APR 2017
MAY 2017 JUN 2017
JUL 2017
AUG 2017 SEP 2017
OCT 2017
EUROPEAN MODEL OUTPUTS: MAY, JUN, JUL 17 JUN, JUL, AUG 17 JUL, AUG, SEP 17
AUG, SEP, OCT 17 NOAA CFS V2 MODEL OUTPUTS - TEMPERATURE and PRECIPITATION:
NOAA OFFICIAL SEASONAL FORECASTS - TEMPERATURE and PRECIPITATION:
AccuWeather s 2016-17 Winter Forecast Monthly HDDs for WINTER 2016-2017 (out of 66 past winters from 1950, GCS = Gas Consuming States): Forecast Made: Oct. 26, 2016: o Winter 2016-2017 Full USA: 242,086 HDDs; 56 th Coldest; o Winter 2016-2017 GCS: 71,098 HDDs; 52 nd Coldest; Forecast Made: Nov. 17, 2016: o Winter 2016-2017 Full USA: 239,191 HDDs; 60 th Coldest; o Winter 2016-2017 GCS: 70,619 HDDs; 56 th Coldest; Forecast Made: Dec. 30, 2016: o Winter 2016-2017 Full USA: 241,470 HDDs; 58 th Coldest; o Winter 2016-2017 GCS: 68,628 HDDs; 59 th Coldest; Forecast Made: Jan. 23, 2017: o Winter 2016-2017 Full USA: 235,356 HDDs; 62 nd Coldest; o Winter 2016-2017 GCS: 67,047 HDDs; 62 nd Coldest; Forecast Made: Feb. 20, 2017: o Winter 2016-2017 Full USA: 229,897 HDDs; 64 th Coldest; o Winter 2016-2017 GCS: 63,427 HDDs; 65 th Coldest; Forecast Made: Mar. 11, 2017: o Winter 2016-2017 Full USA: 226,001 HDDs; 65 th Coldest; o Winter 2016-2017 GCS: 61,837 HDDs; 66 th Coldest; o Final Update: April 15, 2017: o Winter 2016-2017 Full USA: 221,303 HDDs; 65 th Coldest; o Winter 2016-2017 GCS: 60,314 HDDs; 67 th Coldest; o Winter 2015-2016: Winter 2014-2015: Winter 2013-2014: Winter 2012-2013: Winter 2011-2012: Winter 2010-2011: Winter 2009-2010: Winter 2008-2009: Past 5-Winter Average: Past 10-Winter Average: 219,156 HDDs; 66 th Coldest; 244,883 HDDs; 51 ST Coldest; 271,148 HDDs; 8 TH Coldest; 246,808 HDDs; 50 th Coldest; 217,673 HDDs; 67 th Coldest (1 st Warmest); 257,068 HDDs; 38 th Coldest; 247,077 HDDs; 48 th Coldest; 257,958 HDDs; 32 nd Coldest; 240,859 HDDs 247,312 HDDs COLDEST WINTER since 1950-51: 1978-1979; 283,488 HDDs WARMEST WINTER since 1950-51: 2011-2012; 218,673 HDDs