Issued by NWS Sioux Falls, SD
Versions: 1
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000
FGUS73 KFSD 231931
ESFFSD
SDC005-011-027-035-061-067-079-083-087-099-101-111-125-127-135-
MNC033-063-081-083-101-105-117-133-NEC013-014-
IAC021-035-041-059-093-119-141-143-149-167-193-211800-
HYDROLOGIC OUTLOOK
NATIONAL WEATHER SERVICE SIOUX FALLS SD
231 PM CDT THU APR 23 2009
...ADVANCED HYDROLOGIC PREDICTION SERVICES (AHPS) ENABLE THE
NATIONAL WEATHER SERVICE TO PROVIDE LONG-RANGE PROBABILISTIC RIVER
OUTLOOKS...
THIS OUTLOOK IS VALID FROM APR 28 2009 - JUL 27 2009
THE FOLLOWING TABLE GIVES THE CHANCE OF REACHING DIFFERENT
FLOOD LEVELS AT THE GAGES DURING THE VALID PERIOD.
APPROXIMATE CHANCE OF
FLOOD LEVELS (FT) REACHING FLOOD LEVELS
LOCATION MINOR MODRT MAJOR MINOR MODRT MAJOR
-------- ----- ----- ----- ----- ----- -----
JAMES RIVER
HURON SD 11.0 13.0 15.0 > 90% > 90% > 90%
FORESTBURG SD 12.0 14.0 16.0 > 90% > 90% > 90%
MITCHELL SD 17.0 20.0 22.0 > 90% > 90% > 90%
SCOTLAND SD 13.0 14.0 16.0 > 90% > 90% > 90%
FIRESTEEL CREEK
MT VERNON SD 8.0 13.0 15.0 30% < 10% < 10%
W FK VERMILLION RIVER
PARKER SD 9.0 10.0 11.0 < 10% < 10% < 10%
E FK VERMILLION RIVER
PARKER SD 12.0 15.0 16.0 < 10% < 10% < 10%
VERMILLION RIVER
DAVIS SD 11.0 13.0 15.0 15% 10% < 10%
WAKONDA SD 14.0 15.5 17.0 25% 15% 10%
VERMILLION SD 21.0 22.0 30.0 < 10% < 10% < 10%
BIG SIOUX RIVER
BROOKINGS SD 9.0 10.5 12.0 55% 40% 20%
DELL RAPIDS SD 12.0 14.0 15.0 35% 15% 10%
S FALLS 60TH ST 12.0 14.0 16.0 25% 15% < 10%
SF CLIFF AVE 16.0 18.0 31.0 20% 15% < 10%
HAWARDEN IA 15.0 20.0 23.0 50% 20% 10%
AKRON IA 16.0 18.0 20.0 55% 35% 10%
SIOUX CITY IA 99.0 105.0 108.0 < 10% < 10% < 10%
SKUNK CREEK
SIOUX FALLS SD 11.5 15.0 17.0 < 10% < 10% < 10%
SPLIT ROCK CREEK
CORSON SD 8.5 11.0 14.0 15% < 10% < 10%
ROCK RIVER
LUVERNE MN 10.0 12.0 14.0 < 10% < 10% < 10%
ROCK RAPIDS IA 13.0 16.0 19.0 30% 15% < 10%
ROCK VALLEY IA 16.0 17.0 19.0 10% < 10% < 10%
FLOYD RIVER
SHELDON IA 12.0 14.0 16.0 25% 10% < 10%
ALTON IA 12.0 16.0 18.0 45% 20% < 10%
LEMARS IA 20.0 21.0 24.0 10% < 10% < 10%
STRUBLE IA 14.0 15.0 16.0 < 10% < 10% < 10%
MERRILL IA 12.0 14.0 16.0 < 10% < 10% < 10%
JAMES IA 26.0 30.0 34.0 < 10% < 10% < 10%
PERRY CREEK
SIOUX CITY IA 24.0 26.0 28.0 < 10% < 10% < 10%
LITTLE SIOUX RIVER
SPENCER IA 10.0 14.0 16.0 80% 15% 10%
LINN GROVE IA 18.0 19.5 21.0 60% 30% 15%
CHEROKEE IA 17.0 21.0 24.0 35% 15% < 10%
CORRECTIONVILLE 19.0 20.0 21.0 20% 15% 10%
WEST FORK DITCH
HORNICK IA 20.0 22.0 27.0 20% 10% < 10%
REDWOOD RIVER
MARSHALL MN 14.0 15.0 16.5 < 10% < 10% < 10%
DES MOINES RIVER
JACKSON MN 12.0 14.0 16.0 < 10% < 10% < 10%
IN THE TABLE BELOW...THE 90 THROUGH 10 PERCENT COLUMNS INDICATE THE
CHANCE THE RIVER COULD RISE ABOVE THE LISTED STAGE LEVELS IN THE
NEXT 90 DAYS. EXAMPLE: THE JAMES RIVER NEAR SCOTLAND HAS A FLOOD
STAGE OF 13 FEET. THERE IS A 30 PERCENT CHANCE THAT THE RIVER WILL
RISE ABOVE 17.8 FEET IN THE NEXT 90 DAYS.
LOCATION FS(FT) 90% 80% 70% 60% 50% 40% 30% 20% 10%
----------- ---- --- --- --- --- --- --- --- --- ---
JAMES RIVER
HURON 11.0 17.5 17.5 17.5 17.5 17.5 17.5 17.9 18.8 19.8
FORESTBURG 12.0 16.2 16.2 16.2 16.2 16.2 16.3 16.5 17.2 18.8
MITCHELL 17.0 22.4 22.4 22.4 22.4 22.5 22.6 23.0 23.6 25.1
SCOTLAND 13.0 17.1 17.1 17.1 17.1 17.1 17.3 17.8 18.3 19.4
FIRESTEEL CREEK
MOUNT VERNON 8.0 3.0 3.0 3.0 3.1 4.2 6.5 7.8 9.1 11.6
WEST FORK VERMILLION RIVER
PARKER 9.0 1.2 1.2 1.2 1.2 1.5 1.8 2.5 3.3 4.4
EAST FORK VERMILLION RIVER
PARKER 12.0 4.3 4.3 4.3 4.3 4.7 5.9 6.9 8.3 11.4
VERMILLION RIVER
DAVIS 11.0 3.2 3.2 3.5 4.2 5.3 6.1 7.9 10.1 12.6
WAKONDA 14.0 4.8 4.8 4.9 5.4 6.6 8.7 12.1 14.6 17.0
VERMILLION 21.0 5.2 5.2 5.2 5.6 7.1 8.7 12.7 14.3 19.9
BIG SIOUX RIVER
BROOKINGS 9.0 5.5 6.6 7.4 8.2 9.5 10.6 11.3 11.9 12.6
DELL RAPIDS 12.0 6.7 7.2 8.1 8.8 10.1 11.3 12.4 13.4 14.9
60TH STREET 12.0 6.6 7.1 7.7 8.3 9.3 10.3 11.5 12.8 15.3
NORTH CLIFF 16.0 8.8 9.2 9.7 10.5 11.5 12.8 14.4 16.6 22.1
HAWARDEN 15.0 9.4 11.6 13.0 13.7 15.2 16.3 18.3 20.1 22.6
AKRON 16.0 10.9 12.8 14.2 14.9 16.4 17.5 19.2 20.8 22.7
SIOUX CITY 99.0 86.4 87.0 87.4 88.2 89.2 90.1 91.7 93.5 96.7
SKUNK CREEK
SIOUX FALLS 11.5 4.5 4.9 5.3 5.8 6.2 6.5 7.1 7.4 8.9
SPLIT ROCK CREEK
CORSON 8.5 2.6 3.9 4.3 4.9 5.2 5.7 6.4 7.3 9.9
ROCK RIVER
LUVERNE 10.0 3.6 4.2 4.4 4.5 4.7 4.9 5.6 6.1 8.1
ROCK RAPIDS 13.0 9.0 10.0 10.4 11.3 11.6 12.0 12.8 14.9 18.4
ROCK VALLEY 16.0 6.5 7.6 8.3 9.1 9.5 10.1 10.5 12.9 16.4
FLOYD RIVER
SHELDON 12.0 6.2 7.2 7.4 7.9 8.5 9.3 10.5 12.5 14.2
ALTON 12.0 7.9 9.1 9.7 10.4 11.3 13.0 14.5 15.6 17.0
LE MARS 20.0 12.4 13.0 13.6 14.0 15.2 16.4 17.4 19.4 20.3
MERRILL 20.0 1.7 2.4 2.7 3.2 4.0 5.0 6.2 7.6 9.1
JAMES 26.0 11.2 11.8 12.1 12.6 13.3 14.2 15.5 16.8 18.2
WEST BRANCH FLOYD RIVER
STRUBLE 14.0 4.5 5.5 5.9 6.8 7.3 7.5 8.3 9.5 12.7
PERRY CREEK
SIOUX CITY 24.0 7.7 8.2 8.4 8.6 8.8 9.2 9.4 10.6 13.9
LITTLE SIOUX RIVER
SPENCER 10.0 7.7 10.0 10.7 11.3 12.1 12.7 13.0 13.5 15.9
LINN GROVE 18.0 16.8 17.3 17.8 18.0 18.6 19.1 19.4 19.8 22.5
CHEROKEE 17.0 8.5 10.8 11.7 13.6 15.5 16.5 17.5 18.6 22.6
CORRECTIONVILLE 19.0 7.6 8.4 9.1 10.7 12.7 14.3 15.6 18.1 21.3
WEST FORK DITCH
HORNICK 20.0 9.0 10.0 11.4 12.6 13.9 15.4 17.6 19.8 21.6
REDWOOD RIVER
MARSHALL 14.0 8.2 8.3 8.7 9.1 9.3 10.4 11.6 12.2 13.4
DES MOINES RIVER
JACKSON 12.0 4.3 5.4 6.1 6.7 8.1 9.5 9.9 10.5 12.2
THE NUMBERS CONTAINED IN THIS LONG-RANGE PROBABILISTIC OUTLOOK
REPRESENT NATURAL FLOWS. THAT IS...FLOWS UNAFFECTED BY MAN-MADE
STRUCTURES IN THE BASIN SUCH AS DIVERSION DAMS AND RESERVOIRS.
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...SNOW COVER...AND SOIL MOISTURE...AND THE 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 SERVICES (AHPS).
LONG-RANGE PROBABILISTIC OUTLOOKS WILL BE ISSUED TOWARD THE END OF
THE MONTH THROUGHOUT THE YEAR. THE NEXT SCHEDULED OUTLOOK FOR THESE
SITES WILL BE ISSUED TOWARD THE END OF MAY 2009.
VISIT OUR WEB SITE AT WWW.WEATHER.GOV/FSD FOR MORE WEATHER AND RIVER
INFORMATION INCLUDING GRAPHS OF PROBABILISTIC RIVER OUTLOOKS.
$$
MG
