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246 

RWUS32 KFSD 230947

FFSFSD

IAZ001-002-012-MNZ071-072-080-081-089-090-097-098-SDZ040-055-056-061-

062-065>071-231030-



URBAN AND SMALL STREAM FLOOD ADVISORY

NATIONAL WEATHER SERVICE SIOUX FALLS SD

447 AM CDT MON JUL 23 2001



THE NATIONAL WEATHER SERVICE IN SIOUX FALLS...HAS ISSUED AN URBAN 

AND SMALL STREAM FLOOD ADVISORY...EFFECTIVE UNTIL 800 AM CDT MONDAY 

MORNING FOR PEOPLE IN THE FOLLOWING COUNTIES



IN SOUTHEAST SOUTH DAKOTA

     CLAY...UNION...MINNEHAHA...YANKTON...HUTCHINSON...BON HOMME...

     LINCOLN...MCCOOK AND TURNER



IN SOUTHWEST MINNESOTA

     JACKSON...LYON...COTTONWOOD...PIPESTONE...ROCK...MURRAY...NOBLES

     AND LINCOLN



IN NORTHWEST IOWA

     LYON...OSCEOLA AND SIOUX



IN EAST CENTRAL SOUTH DAKOTA

     BROOKINGS...MOODY AND LAKE



SURFACE REPORTS AND NATIONAL WEATHER SERVICE DOPPLER RADAR... 

INDICATES WIDESPREAD RAINFALL OF OVER 1.5 INCHES EARLY THIS 

MORNING...WITH MORE RAIN LIKELY ON THE WAY INTO THE EARLY MORNING 

COMMUTE. SOME LOCALIZED RAINFALL ESTIMATIONS AND REPORTS ARE 

STARTING TO EXCEED 2 INCHES...AND THESE STORMS ARE CAPABLE OF 

RAINFALL RATES OF 2 INCHES PER HOUR. IN ADDITION...SOME LOCATIONS 

HAVE RECEIVED SUBSTANTIAL RAINFALL THE PAST COUPLE OF DAYS ALREADY.



A SLOW MOVING SURFACE BOUNDARY IS PARTIALLY RESPONSIBLE FOR THIS 

RAINFALL. THIS BOUNDARY IS FORECAST TO MOVE DEEPER INTO NORTHWEST 

IOWA AND SOUTHWEST MINNESOTA AS THE MORNING PROGRESSES. UNTIL THAT 

TIME...THERE ARE INDICATIONS THAT RAIN WILL CONTINUE TO DEVELOP 

ALONG AND AHEAD OF THIS BOUNDARY...AND AREA NATIONAL WEATHER SERVICE 

RADARS ARE SHOWING REDEVELOPMENT AT THIS TIME. THE RAIN THAT HAS 

ALREADY FALLEN WILL ALSO CONTINUE TO RUNOFF FOR THE NEXT COUPLE OF 

HOURS...CAUSING SOME GRAVEL BEDS TO WASH OUT IN LOW LYING AREAS OF 

UNPAVED ROADS. STREET FLOODING MAY ALSO BE A PROBLEM FOR THE 

MORNING COMMUTE. 



STAY TUNED TO THE LATEST INFORMATION BY LISTENING TO NOAA WEATHER 

RADIO OR A LOCAL NEWS SOURCE...AND BE ALERT FOR WATER OVER ANY ROADS.

THE SITUATION SHOULD IMPROVE BY 8 AM...ONCE THE SURFACE FRONT HAS 

BEGUN TO PUSH FURTHER EASTWARD. LOCATIONS EAST OF THIS ADVISORY 

SHOULD BE ALERT FOR ANY FUTURE STATEMENTS OR WARNINGS CONCERNING 

FLOODING POTENTIAL.

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