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'!'H 92f\ Water Year 1999 (October 1998 - June 1999) 0, Status reoort. October 1998 throu2h June 1999. In our next issue of "Colorado Climate" we will provide a complete wrap up of th,e .1999 water year. For now, we'll just touch on a few highlights and give a status of where we stand. The words "La Nina" were as common in 1999 as "EI . Nino" had been the year before. Tropical sea surface temperatures dropped quickly during the summer of 1998, and as the autumn began, long"range forecasters were anticipating a dry winter for the southern Rockies and wet weather for the Pacific Northwest with a return of arlie air masses over the Northern Plains (these had been largely absent the previous winter). Temneratures. 1999 has been a warm water year so far. October and December.were slightly above average, while November, January, February and March were all much warmer than average statewide. In fact, 10 out of 12 months, beginning with May 1998 were warmer than the 1961-1990 average for most of the state. This trend ended in April, and each of the past three months have been a bit cooler than average. 10. 1999 WATER YEAR (L 8- _ _n"'_._nn.~n... ~J : : ::::::'h'::::::h__...__...__ __ ........h.mn__n.........hhm ~ 2--" '" I.:: :::::::::::::::::::::::::::::::::::.. .hm.:::::::::::::::::::::::::: -4'. Oct NU\I Dee. Jan Feb Mar Apr May JU{l jul' Aug Sep . 1___ Wtttlrllv.leys -- EaItem~ -+- FootNII -"'0-_'" Precioitation. The 1999 water year got off to a wet and snowy start with a lDl\iorstorm in early October, and three more weeks of stormy weather in late October and early . November. Skiers were excited, and the forecast for a dry winter in southern Colorado appeared to be a bust. The patterns quickly shifted, however, and from mid Novem- ber to th,e end of December, snows were nearly non- existent anywhere in Colorado. The situation improved in January, as frequent snows fell in the Northern and Central Mountains, but February and March were again very dry over most of the state. Despite a tremendous start, statewide snowpack dropped to 89"10 of average by April I and was headed downward. Projections for a warm and dry spring made wllter officials even more edgy. Then, on April 21, one of Colorado's wettest two week periods in recent history began. By May 4, a state- wide average of nearly four inches of precipitation fell in the form of cold rains and wet snows. Precipitation was i especially heavy along the Front Range - see special feature on the spring floods ofl999. June rainAill was spotty, but the effect of the heavy spring precipillltion in combination with the moisture that fell last fell,left Colorado with above average' precipitation for tile first 9 months of the 1999 water year everywhere but a.small portion of the northern mountains and few spots on the northeastern plains. Nine-month totaIsexceeded 150% of average for nearly all of southeastern Colorado and much of the Front Range. COLORADO Oc1'98 - Jun 99 precipillltion as a percent of average. Special Feature: The Spring of 1999 - A Closer Lookat Heavy Rains in April ? ~) After a wet and stormy start, the winter of 1999seltIed down to be dry and remarkably miid. A week otarctic cold just before Christmas caught our. attention lllid deadened our car batteries. Many feared we were in for a long, cold winter after having almost no extreme cold the previous winter. (Actually, Colorado haSn't had a colder than average winter since 1993 - and that wasn't that bad. Are we overdue or what?) Butthe cold left as quickly as it arrived January, February and March were so warm (second warmest on record in some areas, second only to the extremely mild winter of 1954 which preceded one of Colorado's most extreme spring and summer droughts) that what snow did faIl melted quickly. Even in th,e mountains, drivers became .accustomed to bare paVement. '$ From November 12,1998 to ApriI14,J999, Denver temperatures climbed above 50 on two. thirds of thll days and precipillltion totaled barely two. inches. From November 12 through March 31, only 14.4" of snowfall was recorded in Durango with a water content of 2.09". 75 ~ ' ,;. <