By Bill Kappel
Near record monthly precipitation occurred during May with total precipitation exceeding 5 inches for all of us and some areas receiving nearly 10 inches. This was the wettest May since 2015. Unlike that year, almost everything fell as rainfall this month, with just a little snow on the Palmer Divide. This was a different story up in the mountains and shows how important just a few hundred feet of elevation difference can be this time of the year between snow and rain.
All the moisture and clouds kept high temperatures relatively cool. Conversely, the excess moisture kept overnight low temperatures relatively mild. This meant overall temperatures were normal for the month. Another interesting aspect of the weather during May was that several days had a good amount of smoke in the air. This wasn’t from any fires in Colorado, but instead was drawn into the region from the numerous fires burning well to our north in Alberta, Canada. This was the result of a very unusual pattern where a strong ridge of high pressure was present in the Pacific Northwest, with a strong low pressure over the Rockies and upper Midwest and another high pressure over the eastern U.S. This blocked the flow and allowed the smoke to get pulled in low over the Rockies and brought into the Front Range of Colorado.
Weather was quiet and relatively dry during two periods, the first week of the month and the last week of the month. Between these two periods most days received rainfall, sometimes heavy. Most days saw the typical late spring weather pattern with quiet weather in the morning, then building into cumulus clouds by late morning and early afternoon. These would then continue to build into thunderstorms that moved generally west to east and produce an hour or so of rainfall. This type of storm pattern results in variable rainfall accumulation amounts depending on whether a given storm moved over your neighborhood or not.
The strongest storm of the month moved through the region from the 9th through the 12th. This storm moved on the West Coast then into our region and strengthened significantly, producing widespread heavy rain and heavy snow in the higher elevations. Ahead of this storm, southwesterly winds produced our warmest temperatures of the month, with upper 70s on the afternoon of the 9th. The next morning, we woke up to low clouds and a very moist air mass. Then the initial thunderstorms associated with this system formed early in the afternoon. This included severe storms and a few tornadoes just to our north and east. The next round of thunderstorms developed around 4 p.m. that afternoon and produced heavy rain and hail.
As this storm continued to intensify, it stalled out to our south and transitioned from a convective event to produce clouds and steady rainfall. Cooler air also moved in, dropping snow levels. Heavy rainfall continued that evening and into the 11th. Temperatures dropped just enough on the morning of the 11th to produce some measurable snow between 8-10 a.m. over the higher elevations of the Palmer Divide. Snow levels then rose just enough to keep us in rain the rest of the day while at the same time producing heavy snow along the Rampart Range and into Teller County.
The storm continued to produce rainfall and cool temperatures through the next morning. By the time the storm was done, we had received 4-8 inches of rainfall, which produced some flooding in low-lying areas and along I-25. The other unusual aspect of this storm was the nearly continuous rainfall for almost the entire period.
A look ahead
By June we can usually say goodbye to our chance of snowfall but hello to frequent afternoon and evening thunderstorms. Most of the time we can expect warm, sunny days with afternoon and evening thunderstorms.
May 2023 Weather Statistics
Average High: 65.0° (-0.7°)
100-year return frequency value max 75.7° min 57.9°
Average Low: 39.4° (+0.5°)
100-year return frequency value max 43.2° min 32.5°
Highest Temperature: 77°F on the 9th
Lowest Temperature: 31°F on the 1st, 6th
Monthly Precipitation: 5.91” (+3.27” 200% above normal)
100-year return frequency value max 6.94” min 0.15”
Monthly Snowfall: 0.5” (-5.2” 91% below normal)
Season to Date Snow: 71.6” (-50.8” 42% below normal) (the snow season is from July 1 to June 30)
Season to Date Precip: 10.38” (+1.54” 15% above normal) (the precip season is from July 1 to June 30)
Heating Degree Days: 398 (+80)
Cooling Degree Days: 0
Bill Kappel is a meteorologist and Tri-Lakes resident. He can be reached at billkappel@ocn.me.
Other Weather articles
- June Weather Wrap (1/23/2025)
- November Weather Wrap (12/5/2024)
- October Weather Wrap (11/2/2024)
- September Weather Wrap (10/5/2024)
- August Weather Wrap (9/7/2024)
- July Weather Wrap (8/3/2024)
- June Weather Wrap (7/6/2024)
- May Weather Wrap (6/1/2024)
- April Weather Wrap (5/4/2024)
- March Weather Wrap (4/6/2024)