bs D6O,5 8 (| WEEKLY WEATHER -, “ia9| AND CROP BULLETIN U.S. DEPARTMENT U.S. DEPARTMENT OF COMMERCE OF AGRICULTURE National Oceanic National Agricultural and Atmospheric Statistics Service Administration, National and World Agricultural Weather Service Outlook Board Washington, D.C. January 15, 1991 TOTAL PRECIPITATION, INCHES JAN 6-2, 1991 HIGHLIGHTS January 6-12, 1991 Contents Two high pressure systems sliding eastward from the northern Plains to New England provided cold air for a Highlights & Total Precipitation Map ...... ' week of wintry precipitation in the East. A steady flow 1990 Weather Review .............. teeen ar es of subtropical air overrunning the entrenched cold Climate Warming in the United States? triggered rain, ice, and snow. The Northwest saw a Temperature Departure & return to mild, moist air flow off the Pacific Ocean, Extreme Minimum Temperature Maps while the Southwest experienced a warming trend. Rivers Average Temperature & Snow Cover Maps : continued to run high in the Ohio Valley, still above National Weather Data far Selected Cities .... flood stage in portions of eastern Illinois, Indiana, National Agricultural Summary & Ohio, and Kentucky. Heavy rain during the week sent USDA Crop Production Report ° rivers above flood stage in parts of South Carolina, State Summaries of Weather and Agriculture .. Georgia, eastern Texas, and Louisiana. Early in the International Weather and Crop Summary & week, a storm lifted northeastward from the Gulf of December Temperature/Precipitaticn Maps .... Mexico, producing heavy rain along the Gulf Coast and Subscription and Mailing Permit Information .. (Continued to back cover) Weekly Weather and Crop Bulletin January 15, 1991 1990 WEATHER REVIEW A mild winter and spring contributed to one of the The warmth confused trees and crops. The warmest years on record (fig. 1 and table 1), unseasonable mildness accelerated vegetative though wet and stormy weather during the spring and development, leaving crops vulnerable to cold summer resulted in good crop yields in the Plains weather. As a result, a series of freezes in late and Midwest. Though this was the wettest year March damaged early blooming fruit trees in the nationally since 1983 (fig. 2), long-term drought East. Temperatures dipping to 24° F or less on persisted in the West and northern Plains. Summer March 28 damaged fruit crops in the mid-Atlantic heat and dryness damaged crops in the Southeast, States, especially in Virginia’s Shenandoah Valley. which had its warmest year of the century. Forecast Virginia peach production fell by more than 80 percent from a year ago, with apple Winter (December 1989 - February 1990) production expected to drop by 35 _ percent. Pennsylvania cherry output fell by more than 50 December 1989 was the coldest December ever percent. measured for much of the eastern third of the country, and was unusually cold in the central In California, low rainfall and snowfall amounts States as well. The historic cold wave which during the November-March rainy season again raised enveloped most of the country from December 22 to concerns about water supplies, as the 1989-90 24 broke nearly 300 daily temperature records. The precipitation totals were below normal for the freeze extensively damaged fruit and vegetables in fourth consecutive year. For California’s central Texas and Florida. coast and central Sierras, this was the driest 4-year period on record. Near the end of 1990, With the new year, however, came a major change in water levels in California’s largest reservoirs weather patterns, and January 1990 became the were some 40 percent below normal. warmest January since at least 1895, when records kept by the National Climatic Data Center (NCDC) Another long-term drought, this one dating back to began. Though temperatures were above normal late 1987, continued to affect North Dakota and across more than 90 percent of the country, the neighboring States in the northern Plains. The northern Plains saw the greatest anomalies. In winter of 1989-90 worsened the moisture deficits, South Dakota, Huron’s mean temperature of 28° F was as North Dakota had the driest winter this century. 17° F above normal, making this the warmest January Spring and summer storms relieved topsoil dryness since at least 1881. and contributed to reasonable crop yields, but did little to relieve overall dryness. In early The unusual mildness persisted into February, the November, 1990, “subsoil" moisture was reported 15th warmest on record nationwide, and the third short in North Dakota, South Dakota, Montana, and warmest in the Southeast. Nebraska. Spring (March - May) A third area of long-term drought was southeastern Florida, where winter rainfall was one-half of With March the 10th warmest March since 1895, the normal, worsening a drought that began in first three months of the year became the second September, 1988. Water restrictions were imposed warmest such period on record. A notable heat wave in 32 counties. Periods of heavy rains in April, affected the eastern half of the country during May, and later in the year did bring relief. March 12-15, when at least 250 temperature records were equaled or broken, including a summer-like 89° This was a wet and stormy spring across much of the F in Washington, DC. country, with May the outstanding month. Figure 1 U.S. NATIONAL TEMPERATURE ANNUAL, 1895-1990 Fm 3 12.4 12.1 11.8 ceaaaAes ih, ia 11.5 — ai | i 11.2 10.9 10.6 10.3 OeSi eEe 10.0 co © On 10S 7945" fSz25° - 1935 1945 1955 1965 1975 1985 YEAR National Climatic Data Center, NOAA FIG. 1 STRAIGHT HORIZOLNUNTESA ALRE : MAXIMUM VALUE (TOP) —TERM A’V ERAGE (MIDDLE), MINIMUM VALUE (BOTTOM) THE SMOOTH CURVE IS A 9-POINT BINOMIAL FILTER January 15, 1991 Weekly Weather and Crop Bulletin 3 Nationally, this was the second wettest May in the Abundant rains, often accompanied by severe past 30 years. Severe flooding occurred in much of weather, continued to affect heartland areas into the area between the Texas Gulf Coast and Lake August. Nevertheless, farmers eventually got their Michigan due to bouts of heavy rains from mid-April crpps in the ground. Since the fear of an early to mid-May. More than 90 counties in Texas, frost never materialized, and with plenty of Arkansas, and Louisiana were declared federal or growing moisture in the ground, most midwestern State disaster areas. Losses from flooding along farmers realized good crop yields, with national the Arkansas, Trinity, and Red Rivers exceeded $1 corn yields (118.5 bu/ac) close to a record. billion. There were several outstanding heat waves in 1990, High winds, hail, and tornadoes accompanied the but the most notable gripped the southern Plains numerous outbreaks of thunderstorms this spring. and Southwest during June, setting a number of In May alone, preliminary counts showed there were all-time records. On June 24, Lubbock, TX, reached 259 tornadoes. The count for June showed an 110° F, the warmest ever recorded. The next day, 16 incredible 412 tornadoes, which brought’ the cities set daily maximum temperature marks, with year-to-date total to 935, the most for any Phoenix, AZ, setting its all-time high of 120° F. January-June period. On June 2 alone, over 100 That record stood for one day, as the reading on twisters, mostly in Indiana and Illinois, killed 18 June 26 hit 122° F. people and injured hundreds. Heat and dryness promoted numerous outbreaks of The unrelenting rains of spring significantly fires in late June. Six fire fighters lost their delayed summer crop planting in the Midwest, though lives battling a 28,000 acre wildfire in Arizona’s the moisture eradicated remnants of the 1988 Tonto National Forest. In Santa Barbara, CA, a drought still affecting the western corn belt. As fire destroyed 500 buildings as it scorched over of May 27, only 26 percent of the U.S. soybean crop 4000 acres. Additionally, Alaska suffered its had been planted. This compared with an average of third worst fire season, with over 3 million acres 60 percent. . charred, as warm, dry weather persisted during June-August. Summer (June - August) Though most of the South, particularly the lower Heavy rains also flooded the Midwest in June, with Mississippi Valley, was persistently wet through the deadliest occurrence on the night of June 14 at the first half of the year, hot and dry summer days Shadyside, OH, when 3-5 inches of rain in a 3-hour brought drought to much of the region by the end of period resulted in 26 deaths. August. The dryness, which covered coastal Georgia and South Carolina in the spring, spread westward TABLE 1. TOP TEN YEARS WITH LARGE through Alabama to Mississippi by late August. PARTS OF THE CONTIGUOUS U.S. With the Southeast having its seventh driest summer EXPERIENCING WARMER THAN since 1895, crops and pastures shriveled. Peanut, NORMAL ANNUAL TEMPERATURES. corn, and soybean production fell sharply. YEAR Autumn (September - November) 98.8826 Several storm systems, including the remnants of 96.8537 tropical storms Marco and Klaus, deluged the 95.6946 eastern United States in October, leaving the 94.4312 drought little more than a memory. Totals of 8 to 93.1858 20 inches drenched the ground from Pennsylvania 92.6219 southward through eastern Georgia. 90.2976 86.3666 There were 14 named tropical storms and hurricanes 85.9921 this year in the North Atlantic, but only one 85.2692 (Marco) came ashore with winds of tropical storm Figure 2 U.S. NATIONAL MEAN PRECIPITATION INDEX ANNUAL, 1895-1990 INDEX PRECIPITATION 1895 1905 1915 1925 1935 1945 1955 1965 1975 1985 YEAR National Climatic Data Center, NOAA 4 Weekly Weather and Crop Bulletin January 15, 1991 strength. In terms of number of storms, this was Mississippi Valley, and dry in the West (figs. 3 the most active season since 1969. and 4). Dayton and Cleveland had their wettest year ever, with over 50 inches of rain. Regionally On the west coast, frequent frontal incursions (fig. 5), the Central region had its wettest year dropped enough rain and snow to produce two major since at least 1895, when NCDC statistics begin bouts of flooding in western Washington State (table 2). Three States--Illinois, Indiana, and during November. By the end of Thanksgiving Ohio--had the wettest year on record (table 3). weekend, every county west of the Cascade divide The Northeast measured its third wettest year. The reported flood problems, with 3000 people evacuated annual total in Pittsfield, MA, of 68.08 inches from their homes. . Unfortunately, the rain did not beat the old record by 15 inches. The West had its fall farther south where it was needed. Both 10th driest year. Florida endured its fourth October and November rainfall was unusually light driest. in southern California, raising fears the drought there could extend into a fifth year. The annual temperature departure map (fig. 6) shows that only a tiny part of the Northwest had below December 1990 normal temperatures. Since records began, this is the first time that more than 98 percent of the A frigid arctic air mass drove southward from country has been above normal (table 1). Six western Canada on December 18. Biting cold states along the eastern seaboard (table 4) had dominated central and western portions of the their warmest year ever. United States until the end of the year. Record cold in southern California from December 21 to 25 Preliminary data indicate 1115 tornadoes raked severely damaged citrus and vegetable crops. across the countryside this year, a new record Persistent rains along the eastern boundary of the (Zig. This compares with a mean of 757. cold air led to widespread flooding in the However, the year 1973 is a close second at 1102 Tennessee and Ohio Valleys, where a number of tornadoes and may nudge 1990 from first place when cities reported their wettest December ever. final data are received. Florida basked in record warmth much of the month. Douglas Le Comte Summary Managing Editor The year will go down in the record books as unusually wet in the Midwest, Northeast, and lower Figure 3 TOTAL PRECIPITATION, INCHES ANNUAL 1990 Cohen. 903148 NOAA/USDA_JOINT AGRICULTURAL WEATHER FACILITY Based on preliminary reports January 15, 1991 Weekly Weather and Crop Bulletin oO WW a4 O LJ we fe < o lJ oO Le r4 oO 104= < af ou x uJ Oo eeo O — Ke < be LoeO) o & Weekly Weather and Crop Bulletin January 15, 1991 Figure5 U.S. REGIONS 125° 120° 15° 110° 105° i nt Prag © . ; ae i : = 7% he og< 2, per al ; ‘ MEST NORTH CENTRAL~ iS PG ee ate ii EAST NORTH CENTRAL — a Ret Ri igen ppraspeey oe i ep e q'Q y SOUTH Cs “ National Climatic Data Center TABLE 2. TEMPERATURE AND PRECIPITATION RANKINGS FOR JAN-DEC 1990, BASED ON THE PERIOD 1895-1990. 1 = DRIEST/COLDEST, 96 = WETTEST/HOTTEST. PRECIPITATION TEMPERATURE 94 93 EAST NORTH CENTRAL 88 91 CENTRAL 96 89 SOUTHEAST 33 96 WEST NORTH CENTRAL 21 88 SOUTH 83 82 SOUTHWEST 65 78 NORTHWEST 57 83 WEST 10 ci ' NATIONAL 85 90 January 15, 1991 = $ > g s oS TO O 8 a @ = TABLE 3. PRECIPITATION RANKINGS FOR JAN-DEC 1990, BASED ON THE PERIOD 1895 TO 1990. 1 = DRIEST, 96 = WETTEST. | d a s s e b e n s a d e ANNUAL DEPARTURE OF AUG TEMP FROM NORMAL (° F) Weekly Weather and Crop Bulletin January 15, 1991 TABLE 4. TEMPERATURE RANKINGS FOR JAN-DEC 1990, BASED ON THE PERIOD 1895 TO 1990. 1 = COLDEST, 96 = WARMEST. STATE RANK STATE RANK STATE RANK STATE RANK 4Sha 4R4R BRB ARRSGSG SRSSRD tg» Figure 7 TOTAL NUMBER OF TORNADOES, U.S. ANNUAL TOTAL, 1953-1990 is 1000— 800- 600- 400 200+ at 11 BAARLR ABBRRAASBEVTB EA™ 4 aAaens 4 HOP et eT eee Fe eo ee er So ee # 1958 1963 1968 1973 1978 1983 YEAR National Climatic Data Center, January 15, 1991 Weekly Weather and Crop Bulletin CLIMATE WARMING IN THE UNITED STATES? The latest temperature statistics for the United Figure 1 Annual Mean Temperatures States suggest that this country may be seeing some ree Tr signs of the warming trend observed in many other a) Wray ay on parts of the world. Preliminary data from the a ie National Climatic Data Center (NCDC) reveal that s the national average temperature of 53.9° F in 1990 made this .the seventh warmest year since these records began in 1895 (see fig. 1, page 2). For tmhoer e ftihrasnt 9t8i mep ericne ntN CDCo f rtehceo rdcso,u ntrtye mpaevreartaugreeds aboovveer Haea rte ivv a normal. In addition, the average temperature for Northern Hemisphere the past 5 years was comparable to the previous —-} + 4 4 warmest 5-year period, which occurred in the 1930's Many cities along the eastern seaboard reported the warmest year on record in 1990, including Miami, Atlanta, Raleigh, Norfolk, Washington (where records go back to 1872), Baltimore (where records date back to 1870), Atlantic City, and Hartford. Regionally, the Southeast had the warmest year on Southern Hemisphere record, while the Northeast had its fourth warmest. 4+ 4 T4 Globally, preliminary data from several sources indicate 1990 was either the warmest year ever measured (fig. 1) or one of the warmest, continuing the marked upward trend that began in the 1970’s Northern Hemisphere temperatures, paced by especially widespread warmth in March, easily Surpassed previous record years. Southern waif Hemisphere readings were not records but were well Global above long-term means. fn = 4 1860 1880 1900 1920 1940 1960 1980 2000 Before conclusions are drawn about climate change and global warming, some cautionary notes are in P.D. JONES, CLIMATIC RESEARCH UNIT UNIVERSITY OF EAST ANGLIA order. The accuracy of long temperature time NORWICH, UK series, especially for large areas that include the oceans, remains a subject of debate. The extent of 1990 VALUES BASED ON PRELIMINARY DATA the warming caused by "greenhouse gases," urban effects, or other factors also is not clear. The record -for 1990 also shows possible benefits Additionally, the U.S. temperature record shows from a warmer global climate. Thanks, in part, to another runup in temperatures in the 1920’s and a mild winter and spring as well as good growing- early 1930’s prior to the rapid escalation of season rainfall, crop production achieved new greenhouse gas concentrations in the atmosphere. records in Canada and India and approached a record One wonders if anyone can be certain that in the Soviet Union. Add in good yields in the temperatures in coming years will not begin to United States and you have the best year ever for decrease as they did for more than 30 years after global crop production. Other factors besides 1934, the country’s warmest year. weather have contributed to a rising trend in crop production. It is still noteworthy, however, that Nevertheless, an argument against global greenhouse in this year of record warmth the latest U.S. warming has been its lack of confirmation in the Department of Agriculture forecast (1990/91) for continental United States which, because of a dense world grain production of 1.765 billion tons network of stations, should have one of the most exceeds the previous record set in 1986/87 by 5 accurate time series of temperatures. Now, with percent. unusually warm years in 1986, 1987, 1988, and 1990, even skeptical observers can see signs of an erratic trend toward higher temperatures since the late 1970’s. Douglas Le Comte = ® x > = ® £ D — 5 O 2 Q fea) 2 2 ae £ January 15, 1991 DEPARTURE OF AVERAGE TEMPERATURE FROM NORMAL (°F) ' ! Rages ty yom Y 4 . A A ~ 6 4-4 R . g X W , ASS ~ SNI N ISNSON Y G WWWO a M O “ NYN s W .X Q SHADED AREAS ABOVE NORMAL NOAACUSDA AGRICULTURAL WEATHER FACILITY Based on preliminraeproyrt s EXTREME MINIMUM TEMPERATURE (°F) JAN 6-12, 1991