Thunderstorms producing very heavy rain east of Matheson. Several county roads were reportedly flooded.
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Deaths and injuries are direct and indirect together, as the offices filed them. Damage is property and crops in the dollars of the year, not adjusted for inflation, and only where an office estimated it.
The episode as NWS BOU wrote it up.
Thunderstorms producing very heavy rain east of Matheson. Several county roads were reportedly flooded.
The local office's own words before the first event, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.
NWS Denver/Boulder, CO wrote its last area forecast discussion before the first event at May 4, 7:43 PM MST, 53 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DENVER/BOULDER CO 843 PM MDT MON MAY 4 2015 .UPDATE... ISSUED AT 820 PM MDT MON MAY 4 2015 PERSISTENT RAINFALL HAS WARRANTED THE ISSUANCE OF FLASH FLOOD WARNING IN ELBERT COUNTY. RADAR SHOWS THE RAIN TO CONTINUE THERE FOR A COUPLE MORE HOURS ANYWAY. MODELS KEEP SHOWING WIDESPREAD RAIN TO CONTINUE ALL NIGHT OVER MUCH OF THE CWA. WILL MAKE SOME MINOR ADJUSTMENT TO POPS...MAINLY LOWER THEM INT HE FAR NORTHEAST CORNER. && .SHORT TERM...(THIS EVENING THROUGH TUESDAY) ISSUED AT 129 PM MDT MON MAY 4 2015 LIGHTNING HAS BEEN ON THE INCREASE ACROSS THE STATE THIS EARLY AFTERNOON...WITH A FEW STORMS ALONG THE PALMER DIVIDE. STORM MOTION HAS BEEN TOWARDS THE NORTH NORTHEAST...AND RAINFALL RATES THUS FAR OVER THE DIVIDE HAVE BEEN MOSTLY LESS THAN AN INCH AN HOUR. GIVEN THAT...PRECIPITABLE WATER VALUES ARE IN NEAR RECORD TERRITORY FOR EARLY MAY...WITH NAM FORECASTING 0.88 INCHES THIS EVENING. SO WILL HAVE TO WATCH FOR POSSIBLE HEAVY RAIN WITH STORMS...BUT OVERALL THREAT OF SIGNIFICANT FLOODING IS LOW. INITIALLY OVER THE ELEVATED TERRAIN THERE MAY BE SOME SMALL HAIL WITH THESE STORMS. EXPECT CONVECTION TO CONTINUE TO INCREASE THIS EVENING...THEN A TRANSITION TO MOSTLY RAIN SHOWERS LATER THIS EVENING...MIXING WITH STATUS AND FOG OVERNIGHT. LIGHT PRECIPITATION IS EXPECTED TUESDAY EARLY...THEN ANOTHER ROUND WIDESPREAD SHOWERS AND THUNDERSTORMS IN THE AFTERNOON... PROBABLY MORE WIDESPREAD AS THE UPPER LOW APPROACHES FROM THE SOUTHWEST. AGAIN THE MAIN THREAT TUESDAY WILL BE LOCALLY HEAVY RAIN WITH THE STORMS...BUT CANNOT RULE OUT SMALL HAIL AS LIFT ASSOCIATED WITH THE UPPER LOW APPROACHES. .LONG TERM...(TUESDAY NIGHT THROUGH MONDAY) ISSUED AT 129 PM MDT MON MAY 4 2015 A DAMP AND COOL PERIOD WILL PREVAIL THROUGH MUCH OF THE LONG TERM. THE MODELS ARE ALL PRETTY CONSISTENT LIFTING THE LOW OVER COLORADO TUESDAY NIGHT AND WEDNESDAY WITH ATTENDANT QUASIGEOSTROPHIC ASCENT KEEPING THE PRECIPITATION THREAT HIGH. THERE IS A BIT OF LARGE SCALE SUBSIDENCE FORECAST TO MOVE OVERHEAD WEDNESDAY EVENING AND EARLY THURSDAY WHICH WILL PROBABLY RESULT IN LOWER BUT NOT NECESSARILY ZERO POPS DURING THAT TIME FRAME. INCREASING UPSLOPE FLOW AND QG ASCENT ASSOCIATED WITH ANOTHER UPPER LEVEL LOW WILL RETURN LATER THURSDAY AND CONTINUE THROUGH AT LEAST LATE SATURDAY AND PERHAPS INTO SUNDAY. THIS WILL RAMP UP THE PRECIPITATION THREAT AGAIN FOR LATER IN THE WEEK...PERHAPS LEADING TO A SUBSTANTIAL RAIN/SNOW EVENT BY THE WEEKEND...DEPENDING AS USUAL...ON THE EXACT TRACK OF THE CYCLONE. SUBSIDENCE...DRYING AND WARMING LOOK TO BE IN STORE FOR EARLY NEXT WEEK AS THIS SECOND FEATURE MOVES INTO THE GREAT PLAINS. ALL IN ALL IT LOOKS LIKE THE SEVERE WEATHER THREAT SHOULD REMAIN RATHER LOW THROUGH MOST OF THIS TIME FRAME BASED ON FORECAST CAPE VALUES ALTHOUGH THE THREAT OF THUNDERSTORMS WILL BE AROUND... ESPECIALLY DURING THE AFTERNOON AND EVENING HOURS. FORECAST PRECIPITABLE WATER VALUES ARE HIGH ENOUGH TO ALLOW FOR SOME DECENT QPF...ESPECIALLY IN HEAVIER SHOWERS AND THUNDERSTORMS. BURN SCARS IN THE FOOTHILLS COULD HAVE SOME ISSUES IF A STRONGER CONVECTIVE CELL WERE TO PASS BY. && .AVIATION...(FOR THE TAFS THROUGH 06Z TUESDAY EVENING) ISSUED AT 820 PM MDT MON MAY 4 2015 LOW CLOUDS AND LIGHT TO MODERATE RAINFALL WILL BE A GOOD BET ALL NIGHT. CEILINGS SHOULD NOT GET ABOVE BKN035 ALL NIGHT AND VISIBILITIES WILL RANGE FROM 3SM-P6SM WITH THE RAIN AND MAYBE SOME FOG NOW AND AGAIN. && .HYDROLOGY... ISSUED AT 840 PM MDT MON MAY 4 2015 AS MENTIONED ABOVE...THE MAIN PROBLEM AREA HAS TURNED OUT TO BE ELBERT COUNTY WITH SOME TRAINING OF CELLS...BUT MOSTLY ALMOST STATIONARY CELLS. THE RAINFALL BEGAN IN THE EASTERN HALF OF THE COUNTY AROUND 2 PM MDT AND HASEN'T REALLY STOPPED SINCE. WE HAVE BEEN UNABLE TO FIND ANY REAL MEASUREMENTS AS OF YET AND THE RADAR ESTIMATES HAVE BEEN CONTAMINATED BY PLENTY OF SMALL HAIL. THE WARNING IS OUT UNTIL 10 PM MDT AND WE MAY NEED TO EXTEND IT. && .BOU WATCHES/WARNINGS/ADVISORIES... NONE. && UPDATE...RJK SHORT TERM...RTG LONG TERM...ET AVIATION...RJK HYDROLOGY...RJK
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE DENVER/BOULDER CO 1002 AM MDT MON MAY 4 2015 COZ030>051-051615- JACKSON COUNTY BELOW 9000 FEET- WEST JACKSON AND WEST GRAND COUNTIES ABOVE 9000 FEET- GRAND AND SUMMIT COUNTIES BELOW 9000 FEET- SOUTH AND EAST JACKSON/LARIMER/NORTH AND NORTHEAST GRAND/ NORTHWEST BOULDER COUNTIES ABOVE 9000 FEET- SOUTH AND SOUTHEAST GRAND/WEST CENTRAL AND SOUTHWEST BOULDER/ GILPIN/CLEAR CREEK/SUMMIT/NORTH AND WEST PARK COUNTIES ABOVE 9000 FEET-LARIMER AND BOULDER COUNTIES BETWEEN 6000 AND 9000 FEET- JEFFERSON AND WEST DOUGLAS COUNTIES ABOVE 6000 FEET/GILPIN/CLEAR CREEK/NORTHEAST PARK COUNTIES BELOW 9000 FEET- CENTRAL AND SOUTHEAST PARK COUNTY- LARIMER COUNTY BELOW 6000 FEET/NORTHWEST WELD COUNTY- BOULDER AND JEFFERSON COUNTIES BELOW 6000 FEET/WEST BROOMFIELD COUNTY- NORTH DOUGLAS COUNTY BELOW 6000 FEET/DENVER/WEST ADAMS AND ARAPAHOE COUNTIES/EAST BROOMFIELD COUNTY- ELBERT/CENTRAL AND EAST DOUGLAS COUNTIES ABOVE 6000 FEET- NORTHEAST WELD COUNTY-CENTRAL AND SOUTH WELD COUNTY-MORGAN COUNTY- CENTRAL AND EAST ADAMS AND ARAPAHOE COUNTIES- NORTH AND NORTHEAST ELBERT COUNTY BELOW 6000 FEET/NORTH LINCOLN COUNTY- SOUTHEAST ELBERT COUNTY BELOW 6000 FEET/SOUTH LINCOLN COUNTY- LOGAN COUNTY-WASHINGTON COUNTY-SEDGWICK COUNTY-PHILLIPS COUNTY- 1002 AM MDT MON MAY 4 2015 THIS HAZARDOUS WEATHER OUTLOOK IS FOR NORTHEAST AND NORTH CENTRAL COLORADO. .DAY ONE...TODAY AND TONIGHT COOL AND MOIST UPSLOPE FLOW IS IN PLACE TODAY...AND SOME SHOWERS CONTINUE THIS MORNING TO DRIFT NORTH WITH SOUTHERLY FLOW ALOFT. WE EXPECT THUNDERSTORMS TO ERUPT ACROSS THE MOUNTAINS AROUND MIDDAY...THEN SPREAD ACROSS THE PALMER DIVIDE...URBAN CORRIDOR AND FOOTHILLS THIS AFTERNOON. NEAR RECORD PRECIPITABLE WATER VALUES WILL ALLOW FOR LOCALLY HEAVY RAINFALL FROM THE SHOWERS AND STORMS...ESPECIALLY LATE AFTERNOON INTO THE EVENING. SNOW LEVELS WILL BE AROUND 10 THOUSAND FEET WITH A FEW INCHES OF WET SNOW POSSIBLE THROUGH TONIGHT. .DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY WIDESPREAD SHOWERS AND A FEW THUNDERSTORMS WITH LOCALLY HEAVY RAINFALL WILL REMAIN IN THE FORECAST ON TUESDAY. AT THIS TIME...THE MAIN THREAT FOR LOCALLY HEAVY RAINFALL WILL OCCUR FROM THE FOOTHILLS AND I-25 CORRIDOR EASTWARD ACROSS THE PLAINS LATE TUESDAY MORNING THROUGH THE AFTERNOON HOURS. THE HEAVY RAIN THREAT WILL DECREASE TUESDAY EVENING AS AN UPPER LEVEL DISTURBANCE MOVES NORTHEAST OF THE STATE. AT THIS TIME...IT APPEARS THAT MAINLY BURN SCARS WOULD BE MORE SUSCEPTIBLE TO ANY POTENTIAL FLOODING ISSUES. WHILE THE OVERALL THREAT OF SEVERE WEATHER WILL BE LIMITED BY MARGINAL INSTABILITY IN THE ATMOSPHERE...A BRIEF TORNADO WOULD BE POSSIBLE TUESDAY AS WIND SHEAR INCREASES. IN THE HIGHER MOUNTAINS...THE SNOW LEVEL IS EXPECTED TO LOWER INTO THE 9500-10500 FOOT RANGE TUESDAY NIGHT INTO WEDNESDAY MORNING. THE MORE SIGNIFICANT SNOW TOTALS SHOULD STILL BE LIMITED TO THE HIGHER MOUNTAIN PEAKS ABOVE 11 THOUSAND TO 12 THOUSAND FEET...WHERE SEVERAL INCHES TO OVER A FOOT OF SNOW WILL BE POSSIBLE THROUGH WEDNESDAY. UNSETTLED WEATHER WILL REMAIN IN THE FORECAST THROUGH NEXT WEEKEND WITH A CHANCE OF SHOWERS AND STORMS NEARLY EACH AND EVERY DAY. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION WILL NOT BE NEEDED TODAY OR TONIGHT.
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE DENVER CO
855 PM MDT MON MAY 04 2015
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0845 PM HEAVY RAIN 9 WSW LIMON 39.20N 103.83W
05/04/2015 E1.50 INCH ELBERT CO TRAINED SPOTTER
ESTIMATED 1.5 INCHES IN ROUGHLY 2 HOURS.
&&
KBOWENThe Pueblo radar (KPUX), 87 km away, was scanning. The volume nearest the first event began at 03:34 UTC.
1 flash flood. Local standard time, as filed.
Heavy rainfall washed out several county roads.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Colorado in 2015Every state in 2015This day in weather historyWarnings in Colorado, May 2015
NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-09-24. Each event’s entry at NCEI: 581783.