DROUGHT INFORMATION STATEMENT NATIONAL WEATHER SERVICE RIVERTON WY 852 AM MDT SUN JUN 15 2008 ...MUCH ABOVE NORMAL PRECIPITATION IN MAY EASES DROUGHT CONDITIONS ACROSS SOUTHWEST AND WEST CENTRAL WYOMING... SYNOPSIS... THE LATEST U.S. DROUGHT MONITOR FOR WYOMING ISSUED ON JUNE 12 SHOWED THE AREA OF MODERATE /D1/ TO SEVERE /D2/ DROUGHT HAD RETREATED...ESPECIALLY ACROSS FREMONT COUNTY AND THE UPPER GREEN RIVER BASIN. THE AREA CLASSIFIED AS SEVERE DROUGHT WAS CONFINED TO THE NORTHWEST TWO-THIRDS OF SWEETWATER COUNTY AND SOUTHEAST LINCOLN COUNTY. MOST OTHER AREAS IN SOUTHWEST WYOMING WITH THE EXCEPTION OF THE UPPER GREEN RIVER BASIN REMAINED IN MODERATE DROUGHT. NORTH AND CENTRAL WYOMING WERE FREE OF DROUGHT WITH SOUTHERN PARTS OF NATRONA...FREMONT AND TETON COUNTIES AS WELL AS THE UPPER GREEN RIVER BASIN CLASSIFIED AS ABNORMALLY DRY. BASIN-WIDE AVERAGE PRECIPITATION IN MAY WAS 110 TO 210 PERCENT OF NORMAL. AT THE END OF MAY ALL BASINS WITH THE EXCEPTION OF THE UPPER GREEN RIVER BASIN HAD ABOVE AVERAGE SNOWPACK. SUMMARY OF IMPACTS... HYDROLOGIC CONDITIONS HAVE IMPROVED SIGNIFICANTLY FROM ONE YEAR AGO...ESPECIALLY AFTER A MAY WITH OVERALL MUCH ABOVE NORMAL PRECIPITATION IN CONTRAST TO MAY 2007 IN WHICH MOST AREAS RECEIVED BELOW NORMAL PRECIPITATION. THE FOLLOWING TABLE SHOWS THE LATEST AND LAST YEAR PERCENT OF AVERAGE SNOW WATER EQUIVALENT (SWE) AMOUNTS FOR WYOMING BASINS. THE AVERAGE IS BASED ON ALL REPORTING SNOTEL SITES IN THE BASIN AND THE REFERENCE PERIOD FOR AVERAGE COMPARISON IS 1971- 2000. DRAINAGE BASIN 5/26/2008 5/26/2007 SNAKE RIVER 134 15 UPPER YELLOWSTONE 151 36 WIND RIVER 128 20 BIG HORN BASIN 138 38 SHOSHONE 124 23 POWDER-TONGUE 211 48 BELLE FOURCHE MELTED OUT UPPER NORTH PLATTE 124 43 LOWER NORTH PLATTE, SWT 133 37 LITTLE SNAKE RIVER 154 33 UPPER GREEN RIVER 97 18 LOWER GREEN RIVER 126 23 UPPER BEAR RIVER 102 0 WEIGHTED STATE AVERAGE 132 30 FIRE WEATHER IMPACTS. MANY AREAS RECEIVED SIGNIFICANT MOISTURE IN MAY THROUGH EARLY JUNE ALONG WITH COOL CONDITIONS. ALL FIRE WEATHER ZONES WERE IN GREEN-UP OR DELAYED GREEN-UP AT THE HIGHER ELEVATIONS DUE TO COOL CONDITIONS AND DELAYED MELTOFF OF SNOWPACK AND RUNOFF. NO FIRE WEATHER ZONES WERE ASSESSED AS CRITICAL OR FAVORABLE FOR LARGE FIRE GROWTH AS OF JUNE 14. CHECK WITH YOUR COUNTY OFFICIALS FOR THE LATEST BURNING RESTRICTIONS. CLIMATE SUMMARY... OVERALL WYOMING HAD THE 17 WETTEST AND THE 37 COOLEST MAY OVER THE LAST 114 YEARS. SOME AREAS RECEIVED RECORD OR NEAR RECORD PRECIPITATION. LANDER HAD THE WETTEST MAY ON RECORD SINCE 1892... DOWNTOWN RIVERTON HAD THE SECOND WETTEST MAY ON RECORD SINCE 1907... AND CASPER HAD THE FIFTH WETTEST MAY SINCE 1948. MOST AREAS THAT REMAINED IN MODERATE OR SEVERE DROUGHT DID NOT FARE QUITE AS WELL ESPECIALLY IN AREAS THAT REMAIN IN SEVERE DROUGHT ACROSS SWEETWATER COUNTY WHICH RECEIVED NEAR OR BELOW NORMAL PRECIPITATION FOR MAY. BELOW ARE THE TOTAL PRECIPITATION AMOUNTS FROM SELECTED LOCATIONS ACROSS WEST AND CENTRAL WYOMING FOR MAY 2008... LOCATION MAY PRECIPITATION % AVERAGE -------- --------------------- --------- CASPER (AIRPORT) 4.26 179 LANDER (AIRPORT) 6.13 (RECORD WETTEST) 258 RIVERTON (AIRPORT) 4.81 253 ROCK SPRINGS (AIRPORT)* 1.42 104 AFTON* 3.84 175 BIG PINEY* 1.56 154 BITTER CREEK 4NE* 1.20 98 BUFFALO 6.21 255 CODY 4.58 234 DUBOIS 3.40 194 FARSON 5N* 1.60 113 FOSSIL BUTTE NAT MON* 1.31 75 GREEN RIVER* 0.65 54 GREYBULL 2.27 159 JACKSON 1.75 79 KAYCEE 6.25 244 KEMMERER* 0.71 60 LABARGE* 1.33 87 LAKE YELLOWSTONE 4.26 207 LOVELL 2.58 213 MOOSE 1.91 95 OLD FAITHFUL 4.12 169 PINEDALE 3.04 176 POWELL FIELD STATION 2.56 180 RIVERTON DOWNTOWN 4.75 267 THERMOPOLIS 5.01 244 WORLAND 2.67 165 YELLOWSTONE PARK (MAMMOTH) 2.47 123 *LOCATION IN SEVERE OR MODERATE DROUGHT PRECIPITATION/TEMPERATURE OUTLOOKS... THE OUTLOOK FOR THE METEOROLOGICAL SUMMER OR JUNE...JULY AND AUGUST SHOWS A 40 PERCENT CHANCE OF ABOVE NORMAL TEMPERATURES ACROSS MOST OF WEST AND CENTRAL WYOMING WITH A 50 PERCENT CHANCE OF ABOVE NORMAL TEMPERATURES OVER THE SOUTHWEST CORNER. THE PRECIPITATION OUTLOOK FOR THIS PERIOD SHOWS A 40 PERCENT CHANCE OF DRIER THAN NORMAL CONDITIONS OVER ROUGHLY THE NORTH HALF OF WYOMING WITH A SLIGHT CHANCE OF BELOW NORMAL PRECIPITATION ACROSS THE SOUTH. LA NINA CONDITIONS CONTINUED TO WEAKEN DURING MAY. A MAJORITY OF MODELS INDICATE A TRANSITION TO ENSO NEUTRAL CONDITIONS DURING THE REST OF JUNE AND JULY THOUGH THERE IS STILL CONSIDERABLE UNCERTAINTY IN REGARDS TO THIS TRANSITION. THE U.S. SEASONAL DROUGHT OUTLOOK ISSUED ON JUNE 5 SHOWED THAT MODERATE TO SEVERE DROUGHT CONDITIONS IN SOUTHWEST WYOMING WERE EXPECTED TO SHOW SOME IMPROVEMENT...THOUGH DROUGHT CONDITIONS WERE LIKELY TO PERSIST THROUGH AUGUST 2008. HYDROLOGIC SUMMARY AND OUTLOOK... EXCEPT FOR THE UPPER AND LOWER GREEN BASINS...ABOVE NORMAL WATER SUPPLY NUMBERS CONTINUE TO BE EXPECTED FOR THE REST OF JUNE AND INTO JULY FOR THE MAJORITY OF THE LARGE WATERSHEDS IN WYOMING. RECORD AND/OR NEAR RECORD MAY PRECIPITATION ACROSS THE STATE HAS MAINTAINED AND EVEN INCREASED THE FORECASTED SNOWMELT STREAMFLOW VOLUMES FOR THE NEXT TWO MONTHS ACROSS THE MAJORITY OF BASINS IN WYOMING. COOLER THAN NORMAL TEMPERATURES ACROSS WYOMING IN MAY AND EARLY JUNE HAS MAINTAINED AND/OR INCREASED THE ALREADY ABOVE NORMAL SNOW WATER EQUIVALENTS (SWE) OR "WATER" MEASUREMENTS IN THE SNOWPACK ABOVE 9000 FEET. BASIN-WIDE AVERAGE PRECIPITATION FOR MAY WAS 110 TO 210 PERCENT OF NORMAL. FOR THE WATER YEAR 2008...MANY BASINS IN WYOMING WERE REGISTERING 85 TO 120 PERCENT OF NORMAL PRECIPITATION. THE NORMAL TO ABOVE NORMAL PRECIPITATION NUMBERS ACROSS THE STATE HAS GREATLY HELPED INCREASE THE FORECASTED STREAMFLOW VOLUMES IN WYOMING. STREAMFLOW VOLUMES FOR JUNE AND JULY ALONG THE WIND AND BIG HORN RIVER DRAINAGES ARE EXPECTED TO INCREASE TO 105 TO 120 PERCENT OF NORMAL. THE INFLOWS INTO BOYSEN RESERVOIR ARE FORECAST TO BE 105 PERCENT OF NORMAL WITH AN ADDITIONAL 540,000 ACRE-FEET OF WATER EXPECTED TO FLOW INTO BOYSEN RESERVOIR DURING THE REST OF JUNE AND INTO JULY. THE UPPER GREEN AND LOWER GREEN WATERSHED SUPPLY FORECASTS CONTINUE TO POINT TO BELOW AVERAGE SNOWMELT STREAMFLOW VOLUMES WITH ONLY 70 TO 85 PERCENT OF NORMAL STREAMFLOWS EXPECTED THROUGH JULY. NEXT ISSUANCE DATE... THIS PRODUCT WILL BE UPDATED ON TUESDAY JULY 15, 2008 OR SOONER IF NECESSARY IN RESPONSE TO SIGNIFICANT CHANGES IN CONDITIONS. RELATED WEB SITES... LOCAL DROUGHT INFORMATION.
http://www.crh.noaa.gov/riw/hydro/drought.php
WYOMING DROUGHT STATEMENT WITH GRAPHICS.
http://www.crh.noaa.gov/images/riw/hydro/drought_info.pdf NATIONAL RESOURCES CONSERVATION SERVICE SNOW SURVEY
http://www.wrds.uwyo.edu/wrds/nrcs/nrcs.html NATIONAL INTEGRATED DROUGHT INFORMATION CENTER.
http://www.drought.gov NOAA DROUGHT INFORMATION CENTER.
http://www.drought.noaa.gov CLIMATE PREDICTION CENTER
http://www.cpc.noaa.gov/index.php ACKNOWLEDGEMENTS... THE DROUGHT MONITOR IS A MULTI-AGENCY EFFORT INVOLVING THE NATIONAL WEATHER SERVICE AND THE NATIONAL CLIMATIC DATA CENTER...THE USDA...STATE AND REGIONAL CENTER CLIMATOLOGISTS AND THE NATIONAL DROUGHT MITIGATION CENTER. INFORMATION FOR THIS STATEMENT HAS BEEN GATHERED FROM NWS AND FAA OBSERVATION SITES...STATE COOPERATIVE EXTENSION SERVICES...USDA...COE AND USGS. QUESTION AND COMMENTS... IF YOU HAVE ANY QUESTIONS OR COMMENTS ABOUT THIS DROUGHT INFORMATION STATEMENT...PLEASE CONTACT... ARTHUR MEUNIER CLIMATE/DROUGHT FOCAL POINT NATIONAL WEATHER SERVICE RIVERTON, WY 82501 TELEPHONE 307-857-3898 EMAIL: Arthur.Meunier@noaa.gov