EL NIÑO AND CLIMATE CHANGE: (Continued) Monthly Climate Highlights

El Niño Temps & PrecipJanuary 1998

Weather patterns only occasionally deviated from the classic El Niño structure, as Arctic air edged into the northern plains and Pacific storms hit parts of the Pacific Northwest. Frequent storminess continued across the south and east, including a powerful storm that produced flooding in the southeast and one of the worst ice storms on record in parts of New England. In terms of temperatures, arctic air was held at bay, although it occasionally reached the northern plains. Though the temperature fell to -40 F at Jordan, Mont., on the 12th, the only areas of the U.S. where monthly mean temperatures averaged below normal were across portions of Montana and southern California. Monthly mean temperatures were 10 degrees above normal across portions of the Great Basin, northern plains, Ohio Valley, and the Middle Atlantic region.

The persistent storminess lead to record breaking monthly precipitation totals at the following locations: New Orleans, LA (19.28 inches), Mobile, Ala (16.92 inches), Baton Rouge, La. (14.94 inches), Asheville, N.C. (9.96 inches), Roanoke, Va. (7.97 inches), Blacksburg, Va. (7.39 inches), and Burlington, Vt. (5.15 inches). Late in the month, an east coast storm caused beach erosion and dumped record snowfall across the central and southern Appalachians, with Flat Top, W. Va. accumulating 35.0 inches of snow in a 24-hour period on January 27-28. Elsewhere in West Virginia, 24-hour snowfall records were established at Bluefield (21.9 inches) and Beckley (31.0 inches). Storm total snowfall reached 42 inches in Ghent, W. Va. and 40 inches at Beech Mountain, N.C.

During the week of January 5-9, 1998, the eastern U.S. and eastern Canada were severely
affected by a storm system with a very deep southerly flow and abundant moisture. This resulted in flooding rains from the lower Mississippi valley through the southeast and into the northeast, accompanied by several tornadoes, and a severe ice storm in parts of the northeast/New England and into Canada.

The heaviest rains and most severe flooding occurred in the mountains of North Carolina and
northeast Tennessee, where up to 16 inches of rain fell in a two day period in Jackson County, N.C. Estimates indicated over 500 homes either destroyed or with severe damage in North Carolina, and over 200 homes severely damaged or destroyed in Tennessee. Tornado touchdowns produced some damage in Dublin, Ga. and Easley, S.C. Flooding also was a problem in parts of the lower Mississippi valley and upstate New York.

The severe ice storm mainly affected upstate New York, northern New Hampshire and Vermont, much of Maine, and southeast Canada. Some locations received over 3 inches of rain (in the form of freezing rain). Canada reported over 3 million utility customers without power immediately after the storm, while the northeast U.S. reported over 500,000 customers without power. In Maine, four out of five residents lost electrical service at some point during or after the storm, and nearly 3 million feet of power lines were destroyed. Overall damages were well over $2 billion for Canada and over $300 million for the U.S. The last U.S. ice storm to strike with this (or greater) intensity was during February 1994 in the southeast U.S.

February 1998

February was again very warm across most of the continental U.S. aided by the strong El Niño signal. Mean monthly temperatures were as much at 6-16 F above normal across portions of the northern plains. These warm temperatures resulted in many record temperatures including an average temperature of 29.1 F at Sault Ste. Marie, Mich., which was 15.1 F above normal. The only below normal areas in the contiguous U.S. were across portions of the southwest and west coast. Especially impressive was the lack of night-time cold, as temperatures remained above the 20 F mark for the entire month in Topeka, Kan. --the first occurrence since records began 102 years ago. At Madison, Wis., the month's extreme lowest daily temperature was only 11 F, which is equal to their normal daily average February minimum. Unusually cloudy weather continued across a large portion of the eastern half of the country, which acted as a night-time blanket and kept temperatures well above normal. At month's end, the water temperature of Lake Erie at Buffalo was 36 F, the highest on record for the end of the month. The only other seasons that the lake remained unfrozen were 1952-1953 and 1982-1983.

In terms of precipitation, across California and the southwest, four weeks of nearly continuous storminess resulted in widespread flooding, mudslides, and agriculture disruptions. Late in the month a shift in the weather pattern brought some of that storminess out of the southwest and into the northern plains. February precipitation records were set at nearly a dozen locations in the east and at least 19 stations in California. Santa Barbara, Calif., received an incredible monthly total of 21.74 inches, breaking the old record of 17.33 set in 1962 and establishing a record for any month. Records for that location date back to 1867.

Severe thunderstorms produced winds gusts to 104 mph in Miami, 90 mph in Hollywood, and 66 mph in Homestead on the 2nd and 3rd of the month. Over 220,000 Florida Power and Light customers were left without power, as the company said damage to its system was the worst since the "Storm of the Century" in March 1993. Another batch of severe thunderstorms spawned deadly tornadoes across central Florida on February 22-23, killing 42 people.

California Flooding

During the month of February 1998, California was struck by a series of storms due in part to the affects of El Niño. The current estimates indicate over $550 million in damages for the state, with that total expected to climb. The state also reported 17 storm-related deaths for the winter, and 35 counties were declared federal disaster areas. Clear Lake in northern California reached its highest level since 1909, flooding portions of Lakeport, about 90 miles north of San Francisco.

The west coast has dealt with severe flooding for each of the last four winters (including this
year). However, the previous three winters were not significantly influenced by El Niño, thus
showing that (as climatologists have pointed out in prior years) severe flooding can occur on the west coast during non-El Niño years.

Florida Tornadoes

During the late evening of February 22 and early morning of February 23, 1998, a series of
tornadoes ripped across central Florida. At least one of the tornadoes reached an estimated F4 intensity. Forty-two fatalities occurred, over 800 residences were destroyed, another 700 were left uninhabitable, over 3500 were damaged to some extent, and 135,000 utility customers lost power at the height of the storms. Damages from the tornado outbreak exceeded $60 million, and Florida's overall storm damage total since last fall is approximately $500 million. Hardest hit locations in the tornado outbreak were Winter Garden, Altamonte Springs, Sanford, and Campbell. Overall, 54 of Florida's 67 counties were declared federal disaster areas due to storms over the past few months.

March 1998

March's weather featured an impressive cold outbreak (about 150 daily-record lows from March 7-13) followed by a summer-like warm spell (about 200 daily-record highs and more than 20 monthly record highs from March 22-31). The Arctic outbreak produced the coldest weather of the season in many locations across the Central and Southeastern States in an otherwise mild winter. Snow cover protected winter wheat on the central and northern Plains, but in the Southeast, tender vegetation and peach blooms were damaged by three consecutive freezes (March 11-13). March temperatures ranged from 2 to 7 F below normal on the Plains to as much as 5 F above normal in the Great Lakes and Northeastern States. Monthly readings averaged within 2 F of normal in California and the Southwest, although sharply cooler air arrived at month's end, in conjunction with a renewed series of storms.

In California, a month-long stretch without torrential rain--which allowed for recovery from the
February deluge--was replaced by cold, wet conditions toward month's end. Monthly rainfall
totaled more than 200 percent of normal across parts of southern California, the Southwest, and the southern Plains.

An active storm track across the Central and Midwestern States helped to provide abundant
snowfall. Monthly totals of 13.6 inches in Wichita, Kan. and 12.3 inches in Norfolk, Neb.
represented more than 50 percent of their respective season-to-date totals. On southern
California's Mt. Laguna, the snow depth reached 19 inches on March 29. The last two weather systems also produced a wide variety of severe weather, including several tornadoes. On March 20, a total of 15 people were killed in Georgia and North Carolina. Nine days later, two people in Minnesota died in separate tornadoes.

During a 96-hour period early in the month (March 4-8), 4 to 12 inches of rain inundated parts of the Southeast. The downpours, a culmination of a 5-month wet spell, sent rivers to near-record levels in parts of Alabama, Georgia, and western Florida. Meanwhile in Virginia, a continuation of wet conditions through most of the month resulted in record January-March precipitation in locations such as Roanoke (21.17 inches; 232 percent of normal) and Richmond (19.33 inches; 193 percent).

On March 9, streaks of above-normal temperatures ended at 47 days in Moline, IL and 53 days in Milwaukee, WI. Across the Southeast, a 3-day spell of damaging cold commenced on March 11. In the East, the late-month record warmth came just a few days after a significant snowstorm. On March 22, 5.0 inches fell in New York's Central Park, boosting the season-to-date snowfall to 5.5 inches. Nine days later, the Park posted a March-record-tying high of 86 F. On the last 4 days of the month, highs soared to March-record levels in more than 20 locations. Monthly temperatures ranged from 1 to 14 F above normal in Alaska.

Serious drought continued in Hawaii through March. On Oahu, Honolulu experienced their third-driest March (0.03 inches; 1 percent of normal) and January-March (1.01 inches; 13 percent) periods on record. At the major reporting stations, 6-month rainfall ranged from 4.86 inches (28 percent of normal) in Honolulu to 16.68 inches (59 percent) in Lihue. Hilo received 37.47 inches (47 percent of normal) from October to March, but only 6.21 inches (18 percent) since January 1, 1998.

April 1998

Under the influence of a very strong southern branch of a split jet stream, below-normal
temperatures prevailed from California into the Southeast. Monthly departures ranged from -2 to -5 F from California to the central and southern Plains. Meanwhile, readings averaged 2 to 7 F above normal across the Nation's northern tier. Because of the unusual warmth, some fruit trees across the Great Lakes and Northeastern States were already in bloom when more typical weather--resulting in several freezes--returned toward month's end.

The jet stream's active southern branch produced unsettled weather across California and the Southwest. Farther east, several April rainfall records were broken across the Ohio Valley and into the Southeast. At month's end, many rivers--including the middle Mississippi and lower Ohio Rivers--remained very high. In contrast, the procession of storms failed to dampen the South Central United States. The dry spell, which stretched to 6 weeks by the end of April, also affected the immediate Gulf Coast and most of Florida, although a late-month storm boosted topsoil moisture from eastern Texas to Florida.

Deadly tornado outbreaks struck on April 1, 8-9, and 16, claiming 45 lives across five
Southeastern States. The last time more people died in April tornadoes was 1979. On the
evening of April 8, an F5 (winds in excess of 260 mph) cut a 21-mile swath across Jefferson
County, Ala., killing 31 people. Through the first 4 months of 1998, the nation's tornado toll
reached 103, the highest calendar-year total since 1984, when 122 died.

During the first half of the month, several storms dumped significant snow from the Southwest to the central High Plains. In the Northeast, however, there was no April snowfall in Rochester, N.Y. for the first time since 1952. Meanwhile, record warmth developed across the Northwest. The last day of the month featured an April-record high of 90 F in Portland, Ore. Nearly all of Alaska wrapped up a third consecutive month with above-normal temperatures. Monthly departures ranged from 0 to +14 F. Drought continued throughout most of Hawaii, although significant improvement occurred in windward (east-facing) areas.

May 1998

The biggest weather story of the month was the tornadoes and severe thunderstorms which
pummeled the northern Great Plains eastward across the Great Lakes states to upstate New York and New England from Saturday evening May 30th through Sunday May 31st. At 8:44pm May 30th a strong tornado, tentatively classified as an F4 on the Fujita damage scale, struck Spencer, South Dakota killing 6 persons, injuring 150 and literally destroying up to 90 percent of the town. As the storm system swept eastward during Sunday, 9 additional deaths occurred in Wisconsin, Michigan, Massachusetts and Pennsylvania due to tornadoes and severe thunderstorms. More than 34 tornadoes (preliminary estimate) occurred on Sunday across the northeastern states. Dozens of people were injured and 15 homes were destroyed in Mechanicville, New York. Winds gusted to 107 mph in Dodge County, Wisconsin, 92 mph near Grand Rapids, Michigan, and 70 to 80 mph around Minneapolis, St. Paul, Minnesota.

About the same time in the Pacific Northwest, heavy rains hit central Oregon from Thursday, May 28th through the weekend. The heaviest rains occurred in Crook, Deschutes, Wheeler, and Jefferson Counties with 7 inches near Prineville. Many small streams and rivers overflowed, resulting in the Governor declaring a state of emergency in Crook county. Fifty homes were damaged in Prineville and 400 were evacuated as water spilled over the Ochoco Dam.

The other major weather event was the fires that developed in Mexico and Central America and the resulting smoke plume which blanketed Texas and effected portions of the central part of the nation. By May 15th, 10,000 fires covering more than 6000 acres of Mexico and Central America generated enough smoke and particulate matter to trigger a health alert from the Texas Natural Resource Conservation Commission. The health alert remained in effect through May 25th.

Other significant events included heavy rains of up to 5 inches over the Midwest on May 2nd and 3rd sent roads under 4 to 5 feet of water in portions of Illinois, Indiana, Michigan, Ohio, and West Virginia. On May 7th, tornadoes struck South Carolina and North Carolina. One person was killed in Edgefield, South Carolina, crushed in their mobile home. Forty-five thousand persons were without power in Winston Salem, North Carolina, while 200 people were sent to shelters in Lincoln County, Georgia as a tornado struck near Lincolnton.

For the month of May, 10 persons were killed by tornadoes alone, not counting severe
thunderstorm deaths. For the first five months of this year, 120 persons have been killed by
tornadoes, compared to the long term average of 61.

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