Spring Snowmelt Flood Potential Outlook

PROBABILISTIC HYDROLOGIC OUTLOOK
NATIONAL WEATHER SERVICE LA CROSSE WI
930 AM CST THU MAR 1 2012

       ...SECOND SPRING HYDROLOGIC SUMMARY AND OUTLOOK...

THE FOLLOWING INFORMATION IS THE SECOND IN A SERIES OF PLANNED FLOOD
OUTLOOKS PROVIDING FLOOD POTENTIAL AND CLIMATOLOGICAL INFORMATION
FOR THIS COMING SPRING. THIS OUTLOOK CONTAINS INFORMATION WHICH WAS
COLLECTED FROM A NUMBER OF SOURCES...INCLUDING THE UNITED STATES
GEOLOGICAL SURVEY /USGS/...US ARMY CORPS OF ENGINEERS /USACE/...
MIDWEST REGIONAL CLIMATE CENTER /MRCC/...AND THE NATIONAL
OPERATIONAL REMOTE SENSING CENTER /NOHRSC/.

THE OUTLOOK WHICH FOLLOWS BELOW IS A SUMMARY OF THE PAST AND PRESENT
BASIN CONDITIONS FOR PORTIONS OF NORTHEAST IOWA...SOUTHEAST
MINNESOTA...AND SOUTHWEST INTO CENTRAL WISCONSIN.


*** FLOOD POTENTIAL HIGHLIGHTS ***

OVERALL...DESPITE THE RECENT PRECIPITATION...THE FLOOD OUTLOOK FOR
THIS COMING SPRING STILL APPEARS TO BE NEAR OR BELOW NORMAL.

A POTENT WINTER STORM DROPPED A GOOD DEAL OF RAIN AND SNOW ON THE
REGION EARLIER THIS WEEK...WITH BETWEEN 0.75 INCHES AND 1.75 INCHES
OF LIQUID WATER.  WE ALSO HAVE A FEW MORE STORMS WE ARE WATCHING IN
THE NEXT FEW DAYS AND WEEKS. BUT DESPITE THE POTENTIAL FOR THIS
ADDITIONAL PRECIPITATION...THE OVERALL FLOOD OUTLOOK CONTINUES TO
BE FOR A LESS THAN NORMAL RISK FOR ANY FLOODING THIS SPRING DUE TO
SNOWMELT.

HYDROLOGIC CONDITIONS ACROSS MOST OF THE UPPER MISSISSIPPI DRAINAGE
HAVE NOT CHANGED SIGNIFICANTLY SINCE THE LAST OUTLOOK ISSUANCE.
THE DRY CONDITIONS GOING INTO THE WINTER SEASON...COMBINED WITH A
CONTINUED OVERALL BELOW-NORMAL SNOW COVER AND MILD TEMPERATURES...IS
KEEPING THE POTENTIAL FOR ANY SIGNIFICANT RUNOFF TO A MINIMUM.

** HOWEVER...IT IS IMPORTANT TO KEEP IN MIND THAT THERE ARE SEVERAL
MORE WEEKS OF WINTER REMAINING...AND CONDITIONS COULD CHANGE. ALSO...
HEAVY SPRING RAINFALL COULD STILL LEAD TO FLOODING PROBLEMS. **


HERE IS A TABLE OF FLOOD POTENTIAL CATEGORICAL PROBABILITIES AND
DEPARTURES FROM NORMAL...VALID 3/5/2012 - 6/3/2012

                                                           DEP FROM
                         ---------FLOOD STAGES---------     NORMAL
                         MINOR     MODERATE    MAJOR      OF REACHING
  LOCATION               STG  PCT   STG  PCT   STG  PCT   FLOOD STAGE
---------------------------------------------------------------------
BLACK RIVER
 NEILLSVILLE             18  <1%    20  ---    22  ---       18% LESS
 BLACK RVR FALLS         47  44%    51  18%    55   1%       16% LESS
 GALESVILLE              12  50%    13  32%    15  <1%       11% LESS

CEDAR RIVER
 LANSING                 18   1%    20  <1%    22  ---    NEAR NORMAL
 AUSTIN WWTP             15  <1%    18  ---    20  ---    NEAR NORMAL
 CHARLES CITY            12   4%    15   1%    18  ---        9% LESS

TURTLE CREEK
 AUSTIN                10.5   9%    12   6%    14   1%        8% LESS

KICKAPOO RIVER
 LA FARGE                12   1%    13  ---    14  ---    NEAR NORMAL
 VIOLA                   14  23%    17  <1%    20  ---        6% LESS
 READSTOWN               11  26%    14  <1%    17  ---        8% LESS
 SOLDIERS GROVE          13  14%    16   1%    19  <1%    NEAR NORMAL
 GAYS MILLS              13  41%    15   3%    17   1%    NEAR NORMAL
 STEUBEN                 12  29%    13  13%    15   1%    NEAR NORMAL

MISSISSIPPI RIVER
 LAKE CITY               16   6%    18  <1%    20  ---       21% LESS
 WABASHA                 12  16%    14   3%    16  <1%       40% LESS
 ALMA DAM 4              16  <1%    17  ---    18  ---       25% LESS
 MINNESOTA CITY DAM 5   660   6%   662   3%   665  <1%       26% LESS
 WINONA DAM 5A          656   6%   659  <1%   661  ---       25% LESS
 WINONA                  13  11%    15   6%    18  <1%       31% LESS
 TREMPEALEAU DAM 6      647   9%   649   3%   651  <1%       26% LESS
 LA CRESCENT DAM 7      641   9%   643   1%   645  ---       25% LESS
 LA CROSSE               12   9%    13   3%  15.5  <1%       30% LESS
 GENOA DAM 8            631  11%   634   1%   636  ---       38% LESS
 LANSING                 17   3%    19  <1%    20  ---       10% LESS
 LYNXVILLE DAM 9        625   8%   628   1%   631  ---       23% LESS
 MCGREGOR                16  19%    20   6%    23  <1%       32% LESS
 GUTTENBERG DAM 10       15  16%    18   1%    21  ---       31% LESS

ROOT RIVER
 HOUSTON                 15   1%    17  <1%    18  ---       11% LESS

SOUTH BRANCH BARABOO RIVER
 HILLSBORO               13  24%    14   8%    16  <1%    NEAR NORMAL

SOUTH BRANCH ROOT RIVER
 LANESBORO               12   1%    16  <1%    18  ---       13% LESS

TREMPEALEAU RIVER
 DODGE                    9  36%    11  <1%    12  ---        6% LESS

TURKEY RIVER
 ELKADER                 12  11%    16   8%    20   4%       31% LESS
 GARBER                  17  19%    20  11%    23   6%       11% LESS

UPPER IOWA RIVER
 DECORAH                 12   1%    13  ---    14  ---       15% LESS
 DORCHESTER HWY 76       14  14%    17   4%    19   3%       22% LESS

WISCONSIN RIVER
 MUSCODA                  9  14%    10   6%    11  <1%       11% LESS

SOUTH FORK ZUMBRO RIVER
 ROCHESTER 37TH ST       14   3%    18  ---    20  ---    NEAR NORMAL

ZUMBRO RIVER
 ZUMBRO FALLS            18   4%    24  ---    26  ---    NEAR NORMAL

STG = STAGE (FEET)
PCT = PERCENT
--- = DISTRIBUTION COMPLETELY BELOW THIS STAGE
DEP = DEPARTURE


...CLIMATE INFORMATION...

DURING THE AUTUMN OF 2011...VERY LITTLE PRECIPITATION FELL ACROSS
THE TRI-STATE AREA. PRECIPITATION DEFICITS RANGED FROM 2 TO 6
INCHES. THIS RESULTED IN A MODERATE /D1/ TO SEVERE /D2/ DROUGHT
DEVELOPING ACROSS MINNESOTA...AND NORTHERN AND WESTERN IOWA.
ABNORMALLY DRY /D0/ CONDITIONS DEVELOPED ACROSS NORTHERN WISCONSIN.

DURING THE WINTER OF 2011-12...PRECIPITATION WAS SLIGHTLY ABOVE
NORMAL. HOWEVER WITH WELL ABOVE-NORMAL TEMPERATURES /5 TO 8
DEGREES/...MUCH OF THE PRECIPITATION FELL IN THE FORM OF RAIN
INSTEAD OF SNOW...AND MUCH OF THE SNOW THAT DID FALL MELTED DUE TO
THE WARMTH.  THROUGH MARCH 1ST...SEASONAL SNOWFALL TOTALS HAVE
RANGED FROM 15 TO 25 INCHES ACROSS SOUTHEAST MINNESOTA...NORTHEAST
IOWA...AND SOUTHWEST AND CENTRAL WISCONSIN...AND FROM 25 TO
40 INCHES ACROSS NORTH-CENTRAL WISCONSIN. NORMAL SNOWFALL IS AROUND
30 INCHES IN THE SOUTH...TO AROUND 40 INCHES IN THE NORTH.

THIS CONTINUED OVERALL DRY WEATHER HAS RESULTED IN FLOW CONDITIONS
WHICH ARE BELOW HISTORICAL NORMALS...ESPECIALLY IN THE MINNESOTA
AND WISCONSIN TRIBUTARIES ABOVE LA CROSSE WI. IN FACT...IN THOSE
AREAS...TH POTENTIAL EXISTS FOR LOW FLOW CONDITIONS TO DEVELOP
THIS SUMMER.

LOOKING AHEAD TO MARCH...TEMPERATURES ARE EXPECTED TO REMAIN
ABOVE-NORMAL...AND PRECIPITATION IS EXPECTED TO BE NEAR TO
ABOVE-NORMAL.

FROST DEPTH REMAINS BETWEEN 8 AND 15 INCHES ACROSS THE REGION. THE
PERIODS OF WARMER WEATHER HAVE NOT BEEN ENOUGH TO WARM THE SOILS
UP APPRECIABLY QUITE YET.  BUT THAT WILL CHANGE IN THE COMING WEEKS.

WITH THE EXCEPTION OF THE TREMPEALEAU /2 TO 6 INCHES/ AND BLACK
/2 TO TO 17 INCHES/ RIVER BASINS...THERE IS VERY LITTLE SNOW DEPTH
ACROSS THE REGION.

LIQUID WATER CONTENT OF THE SNOW COVER IS CURRENTLY LESS THAN AN
INCH AND A HALF ACROSS THE ENTIRE AREA.  SNOW WATER EQUIVALENT
AMOUNTS ARE HIGHER OVER NORTHERN WISCONSIN...GENERALLY 2 TO 4
INCHES...BUT THAT MELT WATER WILL BE COMING DOWN ONLY THE BLACK AND
WISCONSIN RIVERS.


...FLOOD POTENTIAL...

DESPITE THE RECENT PRECIPITATION...THE LIKELIHOOD OF ANY SIGNIFICANT
SPRING FLOODING FROM SNOWMELT RUNOFF REMAINS NEAR TO BELOW AVERAGE
AT THIS TIME.

HYDROLOGIC CONDITIONS ACROSS MOST OF THE UPPER MISSISSIPPI DRAINAGE
HAVE NOT CHANGED SIGNIFICANTLY SINCE THE LAST OUTLOOK ISSUANCE.
THE DRY CONDITIONS GOING INTO THE WINTER SEASON...COMBINED WITH A
CONTINUED BELOW-NORMAL SNOW COVER AND MILD TEMPERATURES...IS KEEPING
THE POTENTIAL FOR ANY SIGNIFICANT RUNOFF TO A MINIMUM.

WHILE THESE CONDITIONS DO NOT TRANSLATE INTO A SIGNIFICANT FLOOD RISK
ON THE MAINSTEM MISSISSIPPI DUE TO SNOWMELT RUNOFF AT THIS TIME...AS
ALWAYS...THE POTENTIAL FOR FLOODING FROM SPRING RAINFALL REMAINS...
ESPECIALLY ON THE TRIBUTARY STREAMS...AND ESPECIALLY THE BLACK AND
TREMPEALEAU RIVER BASINS...WHICH RECEIVED THE MOST SNOWFALL A FEW
DAYS AGO.

** IT IS IMPORTANT TO KEEP IN MIND THAT THERE ARE SEVERAL MORE WEEKS
OF WINTER REMAINING...AND CONDITIONS COULD CHANGE. **

THE OUTLOOK TABLE BELOW WILL SHOW THE PROBABILITY FOR FLOODING AT
SEVERAL LOCATIONS AROUND THE REGION.


...ADVANCED HYDROLOGIC PREDICTION SERVICE PROBABILISTIC OUTLOOKS...

THIS OUTLOOK PROVIDES LONG-RANGE PROBABILISTIC RIVER OUTLOOKS FOR
RIVER BASINS IN PARTS OF SOUTHEAST MINNESOTA...NORTHEAST IOWA...
AND SOUTHWEST WISCONSIN.

A BRIEF EXPLANATION OF THE METHODOLOGY USED IN CREATING THESE
FORECASTS IS GIVEN AT THE END OF THIS OUTLOOK.

IN THE TABLE BELOW FOR HIGH WATER...THE 90 THROUGH 10 PERCENT
COLUMNS INDICATE THE CHANCE THE RIVER COULD RISE ABOVE THE LISTED
STAGE LEVELS IN THE NEXT 90 DAYS.  FOR EXAMPLE...THE BLACK RIVER AT
GALESVILLE HAS A FLOOD STAGE OF 12 FEET. IN THE NEXT 90 DAYS THERE
IS A 10 PERCENT CHANCE OF THE STAGE REACHING 13.9 FEET.


CHANCE OF EXCEEDING STAGES AT SPECIFIC LOCATIONS
VALID  3/5/2012 - 6/3/2012

LOCATION FS(FT)   90%   80%   70%   60%   50%   40%   30%   20%   10%

BLACK RIVER
NEILLSVILLE  18   8.9   9.4   9.8  10.1  11.2  12.4  12.7  13.4  14.4
BLK RVR FLS  47  43.6  44.1  44.6  45.1  46.6  47.9  49.0  49.9  52.5
GALESVILLE   12   9.8  10.4  10.8  11.1  12.1  12.5  13.2  13.5  13.9

CEDAR RIVER
LANSING      18  11.4  12.1  12.8  13.4  13.6  14.2  14.5  15.0  15.5
AUSTIN       15   4.9   5.4   6.1   6.5   7.0   7.5   8.0   8.9   9.7
CHARLES CTY  12   3.8   4.7   5.0   5.4   6.3   6.7   7.2   8.3  10.4

TURTLE CREEK
AUSTIN       10   4.4   5.1   5.8   6.7   6.9   7.4   8.2   8.7  10.8

KICKAPOO RIVER
LA FARGE     12   5.2   5.6   6.1   6.3   6.7   7.1   7.6   8.7   9.6
VIOLA        14  11.2  11.6  12.0  12.1  12.6  12.9  13.4  14.2  15.1
READSTOWN    11   7.2   7.8   8.4   8.8   9.8  10.4  10.9  11.5  12.4
SLDRS GROVE  13   9.5  10.1  10.6  11.0  11.6  12.2  12.3  12.9  14.0
GAYS MILLS   13  10.1  10.8  11.5  11.9  12.6  13.1  13.2  13.5  14.4
STEUBEN      12   9.7  10.3  11.1  11.2  11.6  11.7  12.0  12.2  13.1

MISSISSIPPI RIVER
LAKE CITY    16   8.5  10.0  10.7  11.4  11.8  12.2  12.7  13.5  15.6
WABASHA      12   8.4   9.3   9.7  10.2  10.5  11.0  11.4  11.8  13.2
ALMA         16   6.2   7.2   7.8   8.4   8.7   9.1   9.6  10.4  12.5
DAM 5        MM 652.6 653.6 654.3 654.9 655.4 655.9 656.5 657.4 659.8
DAM 5A       MM 647.5 649.2 649.8 650.4 650.9 651.4 652.0 653.0 655.6
WINONA       13   6.6   7.6   8.3   8.9   9.4  10.0  10.5  11.4  14.1
TREMPEALEAU  MM 641.3 642.3 642.8 643.3 643.7 644.1 644.6 645.3 647.3
LA CRESCENT  MM 634.4 635.4 636.1 636.6 637.3 637.9 638.3 638.9 641.2
LA CROSSE    12   6.4   7.0   7.6   8.2   9.0   9.7  10.0  10.5  12.4
GENOA        MM 625.0 626.2 626.9 627.5 628.4 629.0 629.4 629.9 632.0
LANSING      17   8.6   9.0   9.5  10.0  10.6  10.9  11.4  11.7  14.4
LYNXVILLE    MM 617.0 618.3 619.0 619.7 620.4 620.8 621.4 621.8 624.7
MCGREGOR     16  10.5  11.8  12.2  13.2  14.0  14.5  14.8  16.0  17.7
GUTTENBERG   15   9.6  10.9  11.4  12.2  12.8  13.3  13.6  14.4  15.6

ROOT RIVER
HOUSTON      15   4.9   5.6   6.4   6.7   7.1   7.9   8.4   9.6  12.5

SOUTH BRANCH BARABOO RIVER
HILLSBORO    13   6.4   7.4   8.8  11.1  11.9  12.2  12.8  13.2  13.8

SOUTH BRANCH ROOT RIVER
LANESBORO    12   3.4   3.6   4.1   4.3   4.6   4.8   5.4   6.4   8.3

TREMPEALEAU RIVER
DODGE         9   7.7   8.2   8.4   8.6   8.8   9.0   9.1   9.4  10.0

TURKEY RIVER
ELKADER      12   7.7   8.0   8.5   9.2   9.6  10.3  10.9  11.7  14.0
GARBER       17   9.5  10.5  11.0  11.7  12.5  13.5  14.7  17.0  20.5

UPPER IOWA RIVER
DECORAH      12   3.6   3.8   3.9   4.1   4.2   4.4   4.6   5.0   5.9
DORCHESTER   14   9.2   9.7  10.1  10.5  10.9  11.4  11.8  13.0  14.7

WISCONSIN RIVER
MUSCODA       9   5.2   5.9   6.4   6.6   7.1   7.6   8.2   8.9   9.9

ZUMBRO RIVER
ZUMBRO FLS   18   7.6   7.8   8.1   8.9   9.3   9.9  10.5  11.6  13.5

SOUTH FORK ZUMBRO RIVER
ROCHESTER    14   4.0   4.6   4.8   5.0   5.4   5.9   6.4   7.3   7.9


THIS LONG-RANGE PROBABILISTIC OUTLOOK CONTAINS 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 THE COMPLETE
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.

THESE LONG-RANGE PROBABILISTIC OUTLOOKS ARE NORMALLY ISSUED NEAR THE
MIDDLE OF EACH MONTH THROUGHOUT THE YEAR. HOWEVER DURING THE
SPRING...THESE OUTLOOKS ARE INCLUDED WITH ADDITIONAL FLOOD POTENTIAL
INFORMATION.

ALL OF THIS INFORMATION IS ALSO AVAILABLE IN GRAPHICAL FORMAT
ON THE LA CROSSE NWS INTERNET HOMEPAGE AT

HTTP://WWW.WEATHER.GOV/LACROSSE (LOWER CASE).

ADDITIONAL INFORMATION IS ALSO AVAILABLE ON THE NORTH CENTRAL RIVER
FORECAST CENTER WEBSITE AT

HTTP://WWW.CRH.NOAA.GOV/NCRFC

THE NEXT HYDROLOGIC OUTLOOK WILL BE ISSUED ON MARCH 22ND.

$$

WELVAERT/BOYNE


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