199 FGUS71 KRNK 211933 ESFRNK NCC005-009-033-157-169-171-189-193-197-VAC005-009-011-017-019-021- 023-029-031-035-037-045-063-067-071-077-083-089-121-141-143-155- 161-163-173-185-197-515-530-580-590-640-680-690-750-770-775- WVC025-055-063-089-231945- WINTER/SPRING FLOOD POTENTIAL OUTLOOK NATIONAL WEATHER SERVICE BLACKSBURG VA 333 PM EDT THU MAR 21 2013 ...WINTER/SPRING FLOOD OUTLOOK...NUMBER 6...FINAL ...RIVER FLOOD POTENTIAL NEAR NORMAL... THIS IS THE SIXTH AND FINAL IN A SERIES OF ANNUAL WINTER/SPRING FLOOD POTENTIAL STATEMENTS INTENDED TO PROVIDE INSIGHT INTO THE LIKELIHOOD OF RIVER FLOODING (NOT FLASH FLOODING) ACROSS THE BLACKSBURG HYDROLOGIC SERVICE AREA (HSA). THE HSA INCLUDES ALL OR PARTS OF THE JAMES...ROANOKE...UPPER YADKIN...GREENBRIER...NEW ...CLINCH AND HOLSTON RIVER BASINS IN WESTERN VIRGINIA...SOUTHEAST WEST VIRGINIA AND NORTHWEST NORTH CAROLINA. THESE STATEMENTS PROVIDE INFORMATION ON FLOOD THREAT CONDITIONS SUCH AS RECENT PRECIPITATION...SOIL MOISTURE...SNOW COVER AND ITS WATER EQUIVALENT...RIVER ICE CONDITIONS...STREAMFLOW...FUTURE PRECIPITATION AND OTHERS FACTORS. THIS OUTLOOK IS VALID FOR THE PERIOD THROUGH APRIL 4 2013. FOR THE BLACKSBURG HSA THE POTENTIAL FOR FLOODING DURING THE OUTLOOK PERIOD IS CONSIDERED NEAR NORMAL. IN THIS PART OF THE MID-ATLANTIC REGION...IT IS HEAVY RAINFALL THAT IS THE PRIMARY FACTOR LEADING TO RIVER FLOODING. HEAVY RAINFALL CAN RAPIDLY CAUSE RIVER FLOODING AT ANY TIME OF THE YEAR...EVEN WHEN OVERALL RIVER FLOOD POTENTIAL IS CONSIDERED LOW. CURRENT FLOODING... NONE. RECENT PRECIPITATION... A STORM SYSTEM MARCH 18-19 BROUGHT ROUGHLY 0.5 TO 1 INCH OF RAIN ACROSS MOST OF THE HSA AND AN EARLIER STORM MARCH 6-7 BROUGHT 0.5 TO 1.25 INCHES OF RAIN AND SNOW WATER EQUIVALENT. OVERALL MARCH PRECIPITATION TO DATE IS RUNNING CLOSE TO NORMAL ACROSS MOST OF THE HSA. FEBRUARY WAS A FAIRLY DRY MONTH OVERALL WITH AVERAGE PRECIPITATION ACROSS THE PRECIPITATION NETWORK OF 2.07 INCHES OR 70 PERCENT OF THE 30-YEAR NORMAL OF 2.95 INCHES. JANUARY-DECEMBER PRECIPITATION JANUARY WAS EXTREMELY WET ACROSS MOST OF THE BLACKSBURG HSA...WITH AN AVERAGE OF 7.60 INCHES OR 233 PERCENT OF THE JANUARY NORMAL OF 3.26 INCHES. DECEMBER WAS SLIGHTLY DRIER THAN NORMAL WITH AN AVERAGE OF 3.03 INCHES VERSUS THE 30-YEAR NORMAL OF 3.27 INCHES OR 93 PERCENT OF NORMAL. AUTUMN PRECIPITATION AUTUMN PRECIPITATION (SEPTEMBER-NOVEMBER) WAS WELL BELOW NORMAL WITH 7.44 INCHES OR 73 PERCENT OF THE LONG-TERM AVERAGE OF 10.44 INCHES. DROUGHT STATUS... ACCORDING THE U.S. DROUGHT MONITOR VALID AS OF MARCH 19 2013 NO DROUGHT OR ABNORMALLY DRY CONDITIONS EXISTED WITHIN THE HSA. PLEASE SEE WWW.DROUGHT.UNL.EDU/DM/MONITOR.HTML FOR DETAILS. SNOW COVER... SNOW COVER IS MOSTLY NON-EXISTENT ALTHOUGH SOME HIGHER ELEVATIONS MAY HAVE PATCHY SNOW. PLEASE SEE WWW.NOHRSC.NWS.NOAA.GOV FOR MORE INFORMATION ON SNOW COVER. RIVER ICE... RIVER ICE IS NON-EXISTENT AT THIS TIME. STREAMFLOW... STREAMFLOWS ARE GENERALLY IN THE NORMAL RANGE FOR THE TIME OF YEAR. FOR MORE DETAILED INFORMATION ON STREAMFLOW CONDITIONS SEE THE USGS WATERWATCH SITE BELOW. HTTP://WATERDATA.USGS.GOV/WATERWATCH SOIL MOISTURE... THE CPC SOIL MOISTURE RANKINGS SHOW NEAR NORMAL CONDITIONS NOW EXIST FOLLOWING THE VERY WET JANUARY AND SUBSEQUENT DRY FEBRUARY. FOR ADDITIONAL INFORMATION FROM CPC: HTTP://WWW.CPC.NCEP.NOAA.GOV THE UNIVERSITY OF WASHINGTON EXPERIMENTAL SOIL MOISTURE ANALYSIS CONFIRMS NEAR NORMAL SOIL CONDITIONS ACROSS THE HSA. THIS DATA CAN BE ACCESSED AT: HTTP://WWW.HYDRO.WASHINGTON.EDU/FORECAST/MONITOR/INDEX.SHTML RESERVOIRS... ALL MAJOR RESERVOIRS SERVING THE HSA REMAIN NEAR GUIDE CURVES AND/OR CONSERVATION POOL LEVELS. FUTURE WEATHER CONDITIONS... TWO STORM SYSTEMS WILL AFFECT PORTIONS OF THE HSA DURING THE LATE WEEK AND UPCOMING WEEKEND WITH THE POSSIBILITY OF LIGHT TO MODERATE PRECIPITATION. PRECIPITATION AMOUNTS OVER THE 5-DAY PERIOD ENDING TUESDAY MARCH 26 AT 1200Z WILL RANGE FROM ABOUT 0.50 INCHES UP TO OVER 1 INCH OF RAIN AND OR SNOW AND MIXED PRECIPITATION. NO FLOODING WOULD RESULT FROM AMOUNTS IN THIS RANGE. ENSEMBLE METEOROLOGICAL AND HYDROLOGICAL FORECASTS FOR THE PERIOD THROUGH NEXT WEEK (MARCH 28) DO NOT SHOW ANY SIGNIFICANT PROBABILITY OF RIVER FLOODING IN ANY OF THE HSA RIVER BASINS. LONGER TERM OUTLOOKS (6-10 AND 8-14 DAY) FROM THE CLIMATE PREDICTION CENTER VALID THROUGH MARCH 30 AND APRIL 2 SUGGEST A VERY HIGH PROBABILITY FOR BELOW NORMAL TEMPERATURES BUT ALSO BELOW NORMAL PRECIPITATION ACROSS MOST OF THE REGION. THE MOST RECENT (MAR 28) MONTHLY OUTLOOK FROM CPC FOR APRIL SHOWS AN ENHANCED PROBABILITY OF ABOVE NORMAL TEMPERATURES AND EQUAL CHANCES FOR ABOVE OR BELOW NORMAL PRECIPITATION IN THE BLACKSBURG HSA. REPEATING THE CURRENT FLOOD POTENTIAL OUTLOOK: NEAR NORMAL. THIS IS THE FINAL WINTER/SPRING OUTLOOK FOR THE 2013 SEASON UNLESS CONDITIONS WARRANT ADDITIONAL OUTLOOK (S). $$ PC