24 Hour Rainfall Estimates. This is just since late last night, based on MPX Doppler radar estimates. Some 4-5" amounts fell from Marshall and Redwood Falls to Gaylord, with 2 to 3.5" over much of the south metro, where extensive flooding is taking place as torrential rain falls on waterlogged soils, resulting in immediate run-off into streets, streams and rivers. More widespread flooding is likely today across southern and central Minnesota.
MSP International Airport has picked up 3.47" rain from this latest volley of storms.
Training Storms. The outflow boundary (minature rain and hail-cooled front) from last night's MCS system is igniting a conga-line of additional T-storms; a few more waves of heavy rain will come through the metro by midday. About 2.3 to 2.4" has already fallen at MSP International since midnight - another 1-3" of rain can't be ruled out. NWS Doppler radar at 9:10 AM.
1). Today is the wettest day of 2014, to date. Old record is 2.44" rain in 1954.
2). We've set a new record for the wettest start to any year since 1871, approaching 23" at MSP.
3). The 3 wettest days at MSP have all occurred within the last month.
Flash Flooding To Continue. Here's the latest update from NOAA regarding a serious - and growing - flood risk across the southern third of Minnesota, including the Twin Cities:
MESOSCALE PRECIPITATION DISCUSSION 0140 NWS WEATHER PREDICTION CENTER COLLEGE PARK MD 926 AM EDT THU JUN 19 2014 AREAS AFFECTED...SOUTHERN MN/NORTHERN IA/SOUTHWEST WI CONCERNING...HEAVY RAINFALL...FLASH FLOODING LIKELY VALID 191326Z - 191926Z SUMMARY...FLASH FLOODING WILL BECOME INCREASINGLY LIKELY ACROSS THE MOST SUSCEPTIBLE AREAS AS CONVECTION ACCOMPANIED BY HIGH RAINFALL RATES EXPANDS. DISCUSSION...CURRENT ANALYSIS AND OBSERVATIONAL TRENDS INDICATE GREATER COVERAGE AND PERSISTENCE OF CONVECTION OCCURRING NORTH OF A STATIONARY FRONT DRAPED ACROSS CENTRAL IOWA...FFG VALUES CONTINUE TO LOWER IN RESPONSE TO ANTECEDENT AND ONGOING RAINFALL. THESE TRENDS ARE ON CONTRAST THE MAJORITY OF HIGH RESOLUTION NUMERICAL GUIDANCE THAT SUGGESTS CONVECTION SHOULD BE WANING. HELPING TO SUSTAIN CONVECTION IS ENHANCED STORM RELATIVE CONVERGENCE AND ASCENT CREATED BY THE NORTHEASTERLY FLOW NORTH OF THE FRONT AND MODERATE SOUTHWESTERLY FLOW ASCENDING THE SLOPING FRONT. CONVECTION IS ALSO EXPANDING WITHIN THE WARM SECTOR SOUTH OF THE FRONT INCLUDING MUCH OF SOUTHWEST IOWA...SUPPORTED BY NEARLY SATURATED SURFACE TO 700 MB MOISTURE ADVECTION AND NEARLY ZERO CIN WHICH IS EVIDENT BY RADAR TRENDS AND THE 12Z KTOP RAOB...AND DEPICTED AT THE SURFACE AS A WAVE OF LOW PRESSURE OVER SOUTHEAST NEBRASKA. FINALLY...THERE IS CONSIDERABLE DISPARITY BETWEEN WSR-88D AND DUAL POL RAINFALL ESTIMATES...WITH THE DUAL POL ESTIMATES AS MUCH AS 50 TO 100 PERCENT HIGHER. GAGE OBSERVATIONS ARE TOO SPARSE AT THE MOMENT TO DETERMINE WHICH ESTIMATES ARE MORE CORRECT. ASSUMING THAT BOTH TECHNIQUES ARE SOMEWHAT CORRECT...COARSE ESTIMATES OF HOURLY RAINFALL RATES OF 0.5 TO 1.5 ARE LIKELY TO CONTINUE...WHICH ARE LIKELY TO EXACERBATE EXISTING FLOODING PROBLEMS.