Tuesday, June 14, 2011

1"+ Rains Overnight? (Flash Flood Warning far southwestern MN)

"Thunder-Wear Alert." The latest NAM model prints out close to an inch and a quarter of rain between now and Wednesday morning as a slow-moving frontal boundary pushes across the state. The risk of severe storms is small (too much cool/stable air in place) but I could see some localized flooding problems, as much as 1.5-2" in a few towns by midday tomorrow.


Doppler at 2:55 pm. Radar shows a smear of showers and heavier thunderstorms pushing across southwestern and south central Minnesota - rain arrives by late afternoon or evening, continues (heavy at times) into the early morning hours Wednesday.

Flash Flood Warning. The local Chanhassen office of the NWS has issued a Flash Flood warning for extreme southwestern Minnesota - very slow moving storms have dumped out several inches of rain on saturated soil. Some flooding of streets, basements and streams is likely into Tuesday night. Here are the details:

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE SIOUX FALLS SD
301 PM CDT TUE JUN 14 2011

THE NATIONAL WEATHER SERVICE IN SIOUX FALLS HAS ISSUED A

* FLASH FLOOD WARNING FOR...
  JACKSON COUNTY IN SOUTHWEST MINNESOTA
  NOBLES COUNTY IN SOUTHWEST MINNESOTA
  NORTHEASTERN LYON COUNTY IN NORTHWEST IOWA
  NORTHERN DICKINSON COUNTY IN NORTHWEST IOWA
  NORTHERN OSCEOLA COUNTY IN NORTHWEST IOWA
  SOUTHERN MURRAY COUNTY IN SOUTHWEST MINNESOTA

* UNTIL 600 PM CDT

* AT 250 PM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED
  THUNDERSTORMS WITH VERY HEAVY RAINFALL ACROSS THE WARNED AREA. ONE
  TO TWO INCHES OF RAIN HAVE ALREADY FALLEN IN THE WARNED AREA. AN
  ADDITIONAL ONE TO TWO INCHES OF RAINFALL IS EXPECTED THROUGH 5 PM
  CDT.

* RUNOFF FROM THIS EXCESSIVE RAINFALL WILL CAUSE FLASH FLOODING TO
  OCCUR. SOME LOCATIONS THAT WILL EXPERIENCE FLOODING INCLUDE...
  JACKSON...SPIRIT LAKE...WORTHINGTON...ADRIAN...ARNOLDS PARK...
  BERGEN...BREWSTER...ELLSWORTH...FULDA...GEORGE...HARRIS...HERON
  LAKE...LAKE PARK...LAKEFIELD...LISMORE...LITTLE ROCK...OCHEYEDAN...
  OKOBOJI...ORLEANS...ROUND LAKE...RUSHMORE...SIBLEY...SUPERIOR...
  WAHPETON...WEST OKOBOJI AND WILMONT.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

EXCESSIVE RUNOFF FROM HEAVY RAINFALL WILL CAUSE FLOODING OF SMALL
CREEKS AND STREAMS...HIGHWAYS AND UNDERPASSES. ADDITIONALLY...COUNTRY
ROADS AND FARMLANDS ALONG THE BANKS OF CREEKS...STREAMS AND OTHER LOW
LYING AREAS ARE SUBJECT TO FLOODING.

EXCESSIVE RUNOFF FROM HEAVY RAINFALL WILL CAUSE FLOODING OF SMALL
CREEKS AND STREAMS...COUNTRY ROADS...AS WELL AS FARMLAND ALONG THE
BANKS OF CREEKS AND STREAMS.

DO NOT DRIVE YOUR VEHICLE INTO AREAS WHERE THE WATER COVERS THE
ROADWAY. THE WATER DEPTH MAY BE TOO GREAT TO ALLOW YOUR CAR TO CROSS
SAFELY.

Gulley-Gushing Rains? The 12z NAM model prints out 1.27" of rain by breakfast on Wednesday - plan on a slow, puddle-infested AM commute tomorrow.

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