June 10 to June 16: This week in Denver weather history

We are entering the primetime of Colorado’s severe weather season. Our look back at Denver weather history for this week shows numerous damaging, dangerous and deadly weather events.

From the National Weather Service:

9-10

In 1864…high water from melting snow combined with heavy rains over the upper reaches of the South Platte River forced the river over its banks and caused flooding of low lying areas along the river in the city. The amount of rainfall in the mountains and in the city is unknown.

10

In 1943…a man was killed by lightning while using a surveying instrument at Buckley Field.

In 1969…hail stones 2 to 3 inches in diameter caused extensive damage to buildings and automobiles in an area from northeast of Boulder to Longmont. Two funnel clouds were reported near Castle Rock. A funnel cloud and 1 inch hail stones were reported 10 to 20 miles southeast of Stapleton International Airport. Hail stones to 1 3/4 inches fell 3 miles west of Littleton. Hail to 3/4 inch diameter fell over southeast Denver.

In 1988…thunderstorm winds clocked to 60 mph unroofed a porch and downed a fence at a home near Stapleton International Airport. A small tornado touched down briefly in northeast Aurora. Another small tornado touched down for 3 minutes in southeast Aurora. No damage was reported from either twister.

In 1989…a national weather service observer saw lightning strike 2 storage tanks at 40th and Havana…3/8 mile northeast of Stapleton International Airport. The strike temporarily knocked out some weather observing equipment at the national weather service.

In 1991…a tornado was sighted 2 miles south of Castle Rock. No damage was reported. The funnel cloud associated with the tornado was sighted for 5 minutes by National Weather Service observers at Stapleton International Airport.

In 1994…lightning struck a home in Denver…which started a fire in the attic and caused minor damage.

In 1997…lightning struck a security guard at the castle pines golf course near Castle Rock. He received only minor injuries.

In 1999…severe thunderstorms rolled off the foothills over metro Denver…producing large hail and damaging winds. Hail to 1 inch diameter fell near Evergreen with 1 3/4 inch hail measured west of Golden. Hail to 1 1/2 inches fell in Commerce City with one inch hail in Lakewood…wheat ridge… The city of Denver and at Denver International Airport where thunderstorm winds gusted to 58 mph. As the storms moved east…3/4 inch hail was reported in Aurora…and damaging thunderstorm winds developed between Bennett and Strasburg. Winds gusting as high as 69 mph blew half a metal roof from a shed in a Bennett lumberyard. A small barn was also leveled between Bennett and Strasburg. Winds also gusted to 58 mph near Manilla.

In 2000…a dry microburst produced a wind gust to 58 mph at Jefferson County Airport. Thunderstorm winds gusted to 55 mph at Denver International Airport.

In 2003…hail as large as 1 3/4 inches was measured at centennial airport and near Parker.

In 2005…hail to 7/8 inch in diameter was reported near Parker with 3/4 inch hail measured near Castle Rock.

In 2009…lightning struck an apartment complex…a veterinary hospital in Boulder and caused minor damage. Lightning also struck two oil tanks…one in Boulder and the other at Front Range airport north of Watkins. The oil tanks in both instances were set on fire and suffered extensive damage.

In 2010…a complex of severe thunderstorms hammered portions of eastern Arapahoe…eastern Douglas and western Elbert counties. The hail ranged from 1 inch to 3 inches in diameter. The largest hail was observed near Elizabeth. Areas in and around Aurora…Byers…Parker and Thornton were also impacted by large hail. One weak tornado touched down near prospect valley but did no damage. At Denver International Airport…a peak wind gust to 35 mph was observed from the northwest.

10-11

In 1882…heavy thunderstorm rains on the morning of the 10th caused a rapid rise in Dry Creek…which enters the South Platte River at Fairview in present day south Denver. This…combined with additional heavy rainfall on the 11th caused the South Platte River to overflow. Five people drowned and several houses were destroyed. Total losses in the city and suburbs was estimated at 75 thousand dollars. Total rainfall in central Denver was 2.21 inches over the 2 days.

11

In 1947…a trace of snow fell over downtown Denver. Low temperature of 34 degrees was a record minimum for the date.

In 1962…hail caused extensive crop damage near Hudson northeast of Denver.

In 1970…stratiform rainfall totaled 3.16 inches at Stapleton International Airport. This was the greatest amount of precipitation ever recorded on a calendar day in June. In addition…it was the greatest amount of precipitation ever measured during any 24-hour period in June. The high temperature climbed to only 51 degrees…which was a record low maximum for the date.

In 1973…large hail from 3/4 to 1 1/2 inches in diameter fell west of Boulder.

In 1977…golf ball size hail was reported just south of Arapahoe County airport…now centennial airport. Lightning struck a home in Lakewood.

In 1988…a 30-year-old man was seriously injured by lightning while mowing his lawn in Denver.

In 1992…lightning started two house fires in the southern Denver suburbs where 3/4 inch hail fell and a funnel cloud was sighted.

In 1999…severe thunderstorms formed over the palmer divide and moved across Douglas…Elbert…and Adams counties. Hail as large as 1 inch in diameter was reported in and near Castle Rock…Sedalia…Franktown…and Aurora. Hail as large as golfballs accumulated several inches deep and caused a large section of a corrugated metal roof of a greenhouse complex to collapse near Franktown. About a third of the roof covering the 30 thousand square foot building collapsed. Thirty-five workers were trapped in the debris…but only 3 were treated for minor injuries. Hail 1 to 2 feet deep blocked the roadways and slowed the arrival of emergency vehicles. Damage to the building was estimated to be around 3 million dollars.

In 2006…a man was struck and killed by lightning as he was returning to his car after leaving the mile high flea market near Henderson. Two others were knocked down…but not injured by the lightning strike. Severe thunderstorms produced large hail across the northern portion of metro Denver. Hail to 1 1/4 inches in diameter was measured in Arvada…with 1 inch diameter hail reported near Fort Lupton. Hail to 7/8 inch in diameter was recorded near Brighton…and hail…3/4 inch in diameter…fell near Keenesburg.

In 2009…large hail pummeled portions of Adams…Arapahoe… Elbert and Douglas counties. Hail up to 1 1/2 inches in diameter was measured near Parker.

In 2010…severe thunderstorms producing very large hail pummeled portions of Front Range foothills and urban corridor. The large hail ranged in size from 1 to 2 1/2 inches…caused extensive damage to home and vehicles. The hardest hit areas included: Brighton… Castle Rock…Greenland…Idledale…Mountain View and Thornton. The combination of heavy rain and hail destroyed 50 thousand acres of cropland in southeast weld County. Flash flooding forced the closure of State Highway 52…east of prospect valley. Several County roads were either flooded or completely washed out. At Denver International Airport…0.69 inches of rainfall was observed.

» Click here to read the rest of June 10 to June 16: This week in Denver weather history

We enjoyed two days with slightly cooler mercury readings but today we once again expect to exceed the 90 degree mark. There will be a slight chance for afternoon and evening thunderstorms but most activity is expected east of us.

We start out the day under mostly sunny skies then will see some clearing in the morning followed by a more clouds in the afternoon and evening. Winds will be light, out of the west this morning, then the northeast in the afternoon.

Temperatures will be heading toward a high in the low 90s, about 10 degrees above normal for the date. After 3:00pm and into the evening we have a slight chance for some thunderstorm activity however, as we said above, most activity will likely not be in our area.

Tonight, partly clear skies will be above with lows dipping to around the 60 degree mark.

A day much like we had yesterday in terms of temperatures. We do expect to see a few more clouds though and perhaps an evening thunderstorm.

We start out under sunny skies then by mid-morning expect to see a few clouds but mostly sunny skies will be with us the balance of the day. Early on we may also see some haze from wildfires in southwestern Wyoming.

Temperatures start out comfortable this morning then begin a climb toward a high in the mid-80s. Most thunderstorm activity will be to our east and southeast but we can’t rule out a small possibility of an isolated, gusty storm in the evening.

Overnight tonight, partly cloudy skies will be above with lows dipping to the mid to upper 50s.

Finally, a little bit of a break from the heat of recent days. Temperatures will still be above normal but far closer to normal than they have been.

The day starts with sunny skies and with a lack of moisture to create clouds, things should remain clear through the day. Temperatures today will top out in the mid-80s, cooler but still above the average high for the date of 81 degrees.

Tonight, skies remain clear with lows dipping to the mid-40s.

We knew the weekend was going to be a scorcher and sure enough, it has been thus far.

Today, the high temperature in Denver as measured at Denver International Airport topped out at 95 degrees at 4:00pm. This tied the record high temperature for June 9 last set in 2012.

Here in Thornton we matched that number with a 95 degree high of our own as well.

This was the second record high temperature reading of the past week as on Tuesday we tied the record high for June 5.

More heat is expected on Sunday with highs potentially coming in a couple of degrees warmer than today. We then will see a weak cold front cool things down slightly Monday and Tuesday but then the heat returns for the latter half of the workweek.  See our extended forecast for details.

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Hot and dry will be the key weather words for the three day period. There will be little variation with temperatures far exceeding normal.

For Friday, we’ll see sunny skies this morning and then a few clouds in the afternoon and evening. Winds will be generally light. Temperatures today will top out in the mid-90s, well above the average high for the date of 80 degrees.

Saturday follows suit with a near clone of today’s weather. Expect to see similarly clear skies and unseasonably warm temperatures.

The weekend closes out with should be the hottest day of the period. Sunday will have a few more clouds but those aren’t expected to inhibit temperatures we expect a high around 98 degrees.

The record high temperature for today’s date is 98 degrees, for the 9th 95 degrees and the 10th 99 degrees. It would not be surprising to see one or two of those records fall. Have a great weekend and stay cool!

The heat is on as temperatures climb for Thornton’s Thursday. Ladies and gentlemen, start your air conditioners! Yesterday’s minimal break from the heat is over and today the mercury will once again climb, hitting the mid-90s.

The day starts out under mostly sunny skies and those will be with us through the morning. Then, this afternoon, cloud cover will increase leading to partly clear skies in the mid-afternoon through this evening.

At this time, it looks like we will remain dry with thunderstorm activity confined to areas northeast of us. Temperatures start out comfortable but will be on a steady climb with readings in the mid-90s expected for much of the afternoon.

Tonight, skies will be partly clear with lows in the mid to upper 50s.

The month of May started off cool and damp but that did not last long.  It soon dried out and warmed up leading to one of the warmest Mays on record.

The first three days of the month brought cool temperatures and generous amounts of rain, more than one inch total.  We then followed that up with a warming trend that for a week.

• May 2018 top shots: Monthly photo slideshow

Temperatures then cooled for the 12th and 13th of the month then started their upward trend again. Another, short break from the warmth came along from the 18th to the 20th.

After that, the warm weather returned and the last eleven days of the month all saw above normal mercury readings.

While there were a few days with rain after the wet start, none really amounted to much.

Thornton’s average temperature for the month came in at 60.5 degrees. By comparison, Denver’s long term average temperature for May is 57.1 degrees. Out at the airport where Denver’s official readings are taken, the month’s average temperature was warmer than ours at 61.4 degrees. That made the month the eight warmest May in Denver history.

Thornton saw its warmest temperature reading for the month of 92.4 degrees on the 26th of the month. The lowest reading of 35.4 degrees fell on the 4th.  Denver saw its warmest reading of 94 degrees on the same day we saw our warmest and its coldest of 40 degrees on the 20th.

Denver set a record high temperature on the 10th and tied the record high temperature for the 25th.  Additionally, the Mile High City saw four days with high temperatures at or above the 90 degree mark (Thornton had three). This breaks the record for the number of 90 degree days in May which previously was three days set in 1989 and 1874.

In terms of precipitation, Denver averages 2.12 inches during May.  Thornton fell well short with 1.59 inches in our bucket. The Mile High City fared better, but still below normal, with 1.86 inches.

No snow fell during the month in Thornton or Denver.

Click here to view Thornton’s May 2018 climate report.

Thornton, Colorado’s May 2018 temperature summary. (ThorntonWeather.com)

Thornton, Colorado’s May 2018 precipitation summary. (ThorntonWeather.com)

CLIMATE REPORT
NATIONAL WEATHER SERVICE DENVER/BOULDER CO
942 AM MDT FRI JUN 1 2018

...................................

...THE DENVER CO CLIMATE SUMMARY FOR THE MONTH OF MAY 2018...

CLIMATE NORMAL PERIOD 1981 TO 2010
CLIMATE RECORD PERIOD 1872 TO 2018

WEATHER         OBSERVED          NORMAL  DEPART  LAST YEAR`S
                 VALUE   DATE(S)  VALUE   FROM    VALUE  DATE(S)
                                          NORMAL
................................................................
TEMPERATURE (F)
RECORD
 HIGH              95   05/26/1942
 LOW               19   05/02/2013
                        05/03/1907
HIGHEST            94   05/26                         86  05/06
LOWEST             40   05/20                         32  05/04
                        05/03
                        05/02
AVG. MAXIMUM     75.4              71.5     3.9     69.6
AVG. MINIMUM     47.5              42.7     4.8     42.3
MEAN             61.4              57.1     4.3     55.9
DAYS MAX >= 90      4               0.8     3.2        0
DAYS MAX <= 32      0               0.0     0.0        0
DAYS MIN <= 32      0               1.9    -1.9        1
DAYS MIN <= 0       0               0.0     0.0        0

PRECIPITATION (INCHES)
RECORD
 MAXIMUM         8.57   1876
 MINIMUM         0.06   1974
TOTALS           1.86              2.12   -0.26     3.66
DAILY AVG.       0.06              0.07   -0.01     0.12
DAYS >= .01         8               9.4    -1.4       17
DAYS >= .10         5               4.8     0.2       11
DAYS >= .50         0               1.2    -1.2        2
DAYS >= 1.00        0               0.2    -0.2        1
GREATEST
 24 HR. TOTAL    0.49   05/03 TO 05/03           05/18 TO 05/18

SNOWFALL (INCHES)
TOTALS            0.0               1.1

DEGREE_DAYS
HEATING TOTAL     151               265    -114      281
 SINCE 7/1       5401              5996    -595     5084
COOLING TOTAL      46                21      25        6
 SINCE 1/1         48                22      26        6

FREEZE DATES
RECORD
 EARLIEST     09/08/1962
 LATEST       06/08/2007
EARLIEST                        10/07
LATEST                          05/05
.................................................................

WIND (MPH)
AVERAGE WIND SPEED              9.9
RESULTANT WIND SPEED/DIRECTION   1/116
HIGHEST WIND SPEED/DIRECTION    36/330    DATE  05/30
HIGHEST GUST SPEED/DIRECTION    52/330    DATE  05/30

SKY COVER
POSSIBLE SUNSHINE (PERCENT)   MM
AVERAGE SKY COVER           0.60
NUMBER OF DAYS FAIR            6
NUMBER OF DAYS PC             15
NUMBER OF DAYS CLOUDY         10

AVERAGE RH (PERCENT)     57

WEATHER CONDITIONS. NUMBER OF DAYS WITH
THUNDERSTORMS            11   MIXED PRECIP           3
HEAVY RAIN                2   RAIN                   2
LIGHT RAIN               11   FREEZING RAIN          0
LT FREEZING RAIN          0   HAIL                   3
HEAVY SNOW                0   SNOW                   0
LIGHT SNOW                0   FOG W/VIS <=1/4 MILE   6
FOG                      10   HAZE                   3

-  INDICATES NEGATIVE NUMBERS.
R  INDICATES RECORD WAS SET OR TIED.
MM INDICATES DATA IS MISSING.
T  INDICATES TRACE AMOUNT.

The evening of June 5 had been relatively calm after a record-tying high temperature. Some high-based thunderstorms then began to move through and created gusty winds.  For some residents, those winds turned damaging.

What appears to have been a microburst (or multiple microbursts), brought fences, broke tree branches and for one Thornton family, toppled a 40 year old tree.  Watch the video below for the story from CBS4.

The winds did appear confined to relatively small areas, hitting hard when they did.  At ThorntonWeather.com, we saw some gusty winds (39mph) but nothing that would cause the type of damage seen by others.

The National Weather Service did report a 54mph gust at Denver International Airport and a 66mph gust at Buckley Air National Guard Base.

Did you suffer damage?  If you have pics, we’d love to see them!

Following yesterday’s record-setting warmth, we get a bit of a respite today. Temperatures will cool but still be well above normal and we will have another chance for afternoon thunderstorms.

The day starts under sunny skies but then a few clouds will be around for the morning. By late morning / early afternoon look for cloud cover to increase as the cold front settles in. Around that same time, we will see breezy winds that will hang around till the evening.

Temperatures will warm steadily toward a high in the upper 80s. As for thunderstorms, we see slight chances from 3:00pm through the evening.

Tonight, skies will be partly clear with lows in the mid-50s.