NZUS90 KGRB 021745 WRKGRB WIC125-085-041-037-075-069-067-083-073-115-125-078-029-141-097- 135-087-061-009-137-139-015-071-DDHHMM- PROBABILISTIC HYDROLOGIC OUTLOOK NATIONAL WEATHER SERVICE GREEN BAY WI 1130 AM CST THU MAR 02 2017 ...Spring Flood and Water Resource Outlook 1... This flood outlook is for the NWS Green Bay service area. It covers the time period from February 18th to May 20th. This includes the following rivers...Yellow...Wisconsin...Wolf...Little Wolf...Fox...Waupaca and Oconto. ...Forecast... For the rest of February. Above normal and at times well above normal temperatures are expected. Temperatures from February 17th to February 22st will climb to 15 to 20 degrees above normal...reaching 50 degrees over parts of the area at times. There is chance for rain showers Monday night into Tuesday and again late next week. The outlook for March indicates near normal temperatures and precipitation. For the period from March to May suggests normal to slightly above normal temperatures and precipitation. ...Ground Conditions... Due to an early snowfall and above normal temperatures...frost depths varied but were less than normal ranging from 8 to 20 inches. A robust January thaw reduced much of the snowpack...ranging from 0 to 5 inches over Northeast Wisconsin...5 to 10 inches over Central Wisconsin...and 10 to 20 inches over North Central Wisconsin with the highest amounts over the snow belt region of Vilas County. Snow water content of that snow was less than 0.50 inch over Northeast Wisconsin...around an inch over Central Wisconsin...and 1 to 2.5 inches over North Central Wisconsin. ...Current Streamflow conditions... Above normal precipitation over North Central Wisconsin in 2016 which included late fall...combined with runoff from the robust January thaw have produced above normal river levels for the headwaters of the main stem rivers. This includes the Wisconsin...Wolf and Menominee rivers. ...Flood summary and potential threats... Forecast conditions this weekend and into the first half of next week point to a significant snowmelt. Conditions which support a fast snowmelt include warm temperatures, wind, sunshine, increasing dewpoints and overnight low temperatures above freezing. Ice Jams during river break will still be possible. Flooding affects from remaining snowfall along with any potential heavy spring rains will again lead to small stream and river rises. Assuming conditions listed above...there is a 25 to nearly 50 percent chance of minor flooding again this spring for part of the Wolf river from Shiocton to Lake Poygan...Yellow River in Wood County and the Menominee River. --------------------------------------------------------- IN TABLE 1 BELOW...THE CURRENT (CS) AND HISTORICAL (HS) OR NORMAL PROBABILITIES OF EXCEEDING MINOR...MODERATE...AND MAJOR FLOOD STAGES ARE LISTED FOR THE VALID TIME PERIOD. CS VALUES INDICATE THE PROBABILITY OF REACHING A FLOOD CATEGORY BASED ON CURRENT CONDITIONS. HS VALUES INDICATE THE PROBABILITY OF REACHING A FLOOD CATEGORY BASED ON HISTORICAL OR NORMAL CONDITIONS. WHEN THE VALUE OF CS IS MORE THAN HS...THE PROBABILITY OF EXCEEDING THAT LEVEL IS HIGHER THAN NORMAL. WHEN THE VALUE OF CS IS LESS THAN HS...THE PROBABILITY OF EXCEEDING THAT LEVEL IS LOWER THAN NORMAL. ...TABLE 1--PROBABILITIES FOR MINOR...MODERATE AND MAJOR FLOODING... VALID PERIOD: 03/05/2017 - 06/03/2017 : CURRENT AND HISTORICAL : CHANCES OF EXCEEDING : FLOOD CATEGORIES : AS A PERCENTAGE (%) CATEGORICAL : FLOOD STAGES (FT) : MINOR MODERATE MAJOR LOCATION MINOR MOD MAJOR : CS HS CS HS CS HS -------- ----- ----- ----- : --- --- --- --- --- --- :WISCONSIN RIVER MERRILL 11.0 13.5 15.0 : 7 17 <5 5 <5 <5 ROTHSCHILD 25.0 27.0 28.0 : 6 16 <5 7 <5 <5 WISCONSIN RAPIDS 12.0 13.5 14.5 : <5 5 <5 <5 <5 <5 :YELLOW RIVER BABCOCK 12.0 15.9 16.6 : 38 71 <5 13 <5 8 :OCONTO RIVER OCONTO 9.0 12.0 14.0 : 14 16 <5 <5 <5 <5 :UPPER WOLF RIVER LANGLADE 11.5 12.5 14.0 : <5 <5 <5 <5 <5 <5 :WOLF RIVER SHIOCTON 12.0 13.5 15.0 : 25 35 6 10 <5 <5 NEW LONDON 9.0 10.5 11.1 : 45 48 <5 5 <5 <5 :LITTLE WOLF RIVER ROYALTON 5.0 8.0 10.0 : 31 41 <5 <5 <5 <5 :WAUPACA RIVER WAUPACA 6.0 7.5 9.0 : <5 5 <5 <5 <5 <5 :FOX RIVER APPLETON 8.4 9.0 10.5 : <5 <5 <5 <5 <5 <5 :MENOMINEE RIVER FLORENCE 9.0 11.0 13.0 : 26 31 8 10 <5 <5 NIAGARA 13.0 15.0 16.0 : 20 28 7 7 <5 <5 VULCAN 15.0 17.0 19.0 : 14 25 <5 6 <5 <5 MCALLISTER 15.0 18.0 19.0 : 48 55 7 9 <5 <5 LEGEND CS = CONDITIONAL SIMULATION (CURRENT OUTLOOK) HS = HISTORICAL SIMULATION FT = FEET IN TABLE 2 BELOW...THE 95 THROUGH 5 PERCENT COLUMNS INDICATE THE PROBABILITY OF EXCEEDING THE LISTED STAGE LEVELS (FT) FOR THE VALID TIME PERIOD. ...TABLE 2--EXCEEDANCE PROBABILITIES... CHANCE OF EXCEEDING STAGES AT SPECIFIC LOCATIONS VALID PERIOD: 03/05/2017 - 06/03/2017 LOCATION 95% 90% 75% 50% 25% 10% 5% -------- ------ ------ ------ ------ ------ ------ ------ :WISCONSIN RIVER MERRILL 7.5 7.9 8.3 8.9 9.8 10.3 11.8 ROTHSCHILD 18.3 19.1 19.8 21.3 22.4 23.7 25.4 WISCONSIN RAPIDS 5.5 5.7 6.0 7.3 8.1 9.9 10.3 :YELLOW RIVER BABCOCK 5.9 7.0 8.2 10.9 13.3 15.2 15.6 :OCONTO RIVER OCONTO 6.8 6.8 7.3 7.7 8.5 9.5 10.4 :UPPER WOLF RIVER LANGLADE 9.1 9.2 9.5 9.7 10.0 10.4 10.5 :WOLF RIVER SHIOCTON 9.7 9.9 10.6 11.5 12.0 13.0 13.7 NEW LONDON 7.7 8.0 8.4 8.9 9.4 9.9 10.1 :LITTLE WOLF RIVER ROYALTON 3.2 3.3 3.7 4.3 5.1 5.8 6.8 :WAUPACA RIVER WAUPACA 2.6 2.7 3.1 3.5 4.1 4.5 4.9 :FOX RIVER APPLETON 6.9 6.9 6.9 7.3 7.7 7.9 7.9 :MENOMINEE RIVER FLORENCE 6.1 6.6 7.3 8.0 9.1 10.6 11.1 NIAGARA 9.3 10.1 10.7 11.6 12.8 14.7 15.3 VULCAN 9.7 10.5 11.3 12.4 13.9 15.8 16.9 MCALLISTER 12.8 13.3 14.3 14.9 16.1 17.3 18.9 IN TABLE 3 BELOW...THE 95 THROUGH 5 PERCENT COLUMNS INDICATE THE PROBABILITY OF FALLING BELOW THE LISTED STAGE LEVELS (FT) FOR THE VALID TIME PERIOD. ...TABLE 3--NONEXCEEDANCE PROBABILITIES... CHANCE OF FALLING BELOW STAGES AT SPECIFIC LOCATIONS VALID PERIOD: 03/05/2017 - 06/03/2017 LOCATION 95% 90% 75% 50% 25% 10% 5% -------- ------ ------ ------ ------ ------ ------ ------ :WISCONSIN RIVER MERRILL 5.3 5.3 5.3 4.9 4.7 4.6 4.6 ROTHSCHILD 14.2 14.1 14.1 13.7 13.5 13.3 12.6 WISCONSIN RAPIDS 3.6 3.5 3.5 3.2 3.1 1.4 1.3 :YELLOW RIVER BABCOCK 2.2 2.1 2.0 1.9 1.9 1.9 1.9 :OCONTO RIVER OCONTO 5.4 5.3 5.1 5.0 4.8 4.7 4.7 :UPPER WOLF RIVER LANGLADE 8.1 8.1 8.0 7.9 7.8 7.8 7.8 :WOLF RIVER SHIOCTON 6.8 6.6 5.8 4.7 4.0 3.6 3.5 NEW LONDON 4.3 4.1 3.5 3.0 2.5 2.2 2.2 :LITTLE WOLF RIVER ROYALTON 1.5 1.5 1.4 1.3 1.3 1.2 1.2 :WAUPACA RIVER WAUPACA 1.7 1.7 1.6 1.6 1.5 1.5 1.5 :FOX RIVER APPLETON 5.7 5.6 5.4 5.2 5.0 4.9 4.9 :MENOMINEE RIVER FLORENCE 3.6 3.6 3.6 3.5 3.4 3.4 3.4 NIAGARA 5.9 5.9 5.8 5.7 5.5 5.5 5.5 VULCAN 5.9 5.9 5.8 5.7 5.5 5.5 5.5 MCALLISTER 9.7 9.7 9.6 9.4 9.3 9.2 9.2 THESE LONG-RANGE PROBABILISTIC OUTLOOKS CONTAIN FORECAST VALUES THAT ARE CALCULATED USING MULTIPLE SEASON SCENARIOS FROM 30 OR MORE YEARS OF CLIMATOLOGICAL DATA...INCLUDING CURRENT CONDITIONS OF THE RIVER...SOIL MOISTURE...SNOW COVER...AND 30 TO 90 DAY LONG-RANGE OUTLOOKS OF TEMPERATURE AND PRECIPITATION. BY PROVIDING A RANGE OF PROBABILITIES...THE LEVEL OF RISK ASSOCIATED WITH LONG-RANGE PLANNING DECISIONS CAN BE DETERMINED. THESE PROBABILISTIC FORECASTS ARE PART OF THE NATIONAL WEATHER SERVICE'S ADVANCED HYDROLOGIC PREDICTION SERVICE. Visit our web site weather.gov/grb for more weather and water information. Additional web sites and information. Latest snowpact from NOHRCS www.nohrsc.noaa.gov/nsa Current streamflows. waterdata.usgs.gov/wi/nwis/rt Long term forecast information. www.cpc.noaa.gov $$