A hazardous weather weekend is shaping up across much of the Lower 48 states, with a potentially historic late May snowstorm cranking up across the Rockies and a heat wave hitting the East Coast.
Why it matters: More than 100 million Americans are experiencing dangerous weather conditions this weekend, as a cold front slams Colorado and southern Wyoming with heavy snow and a potentially record breaking heat wave surges toward the Northeast.
The big picture: A powerful cold front and its associated low-pressure area drove southeastward across the Rockies Friday, bringing heavy snow to parts of Wyoming and Colorado.
- Colorado Springs recorded over 9 inches of snow as of Saturday morning, while multiple towns west of Denver had over 10 inches on Friday night, according to the National Weather Service (NWS).
- The town of Black Hawk, Colorado, reported 11 inches of snow as of Friday evening.
- The highest snowfall amounts recorded Saturday were in the mountains and foothills west of Denver and Boulder, with up to two feet reported around the Floyd Hill area, according to NWS Boulder.
- More than 93,000 customers were without power in Colorado as of Saturday afternoon, according to the tracking service poweroutage.us.
- Multiple reporting locations in Wyoming's portion of the Medicine Bow-Routt National Forests recorded more than a foot of snow on Friday.
The heavy snow is the result of winds pushing cold, moist air up and over the higher terrain, in a phenomenon known as upsloping.
- Importantly, a forecast consensus has come together for more snowfall than previously expected in the urban corridor between Denver and Boulder, Colorado, with about six to eight inches or more possible in these areas, depending on snowfall rates and the exact surface temperature.
- Sharply higher amounts will pile up in the foothills, though, and records for late May could be threatened or broken in some locations. Parts of Boulder, for example, could see a foot of snowfall before the event wraps up on Saturday afternoon
Threat level: The heavy snow falling on trees that already have their leaves could yield widespread tree damage and lasting power outages in the Denver and Boulder areas, and in some cases power may not be restored for days, according to the NWS.
- The agency is warning residents not to park their cars near a tree, since it might topple onto the vehicle.
⚠️Winter Storm Impacts and Preparedness⚠️— NWS Boulder (@NWSBoulder) May 20, 2022
With the heavy wet snow expected to accumulate, significant tree damage will be possible along with scattered power outages. Difficult travel for Front Range Mountains & Foothills starting today, Palmer Divide late this aft/eve. #COwx pic.twitter.com/JOAAllxlag
- To the south of the snowstorm, dry and windy conditions are bringing yet another day of concerning fire weather conditions to parts of Utah, New Mexico and western Texas on Saturday.
- Numerous wildfires are already burning throughout this region, including the Calf Canyon-Hermits Peak Fire, the largest in New Mexico's history. Other fires are burning in southern Colorado and west Texas.
Meanwhile... Across the eastern part of the country, an unusually hot weekend is in store as a heat dome that had been parked over Texas shifts eastward. Widespread record-breaking temperatures are expected across the Mid-Atlantic, Carolinas, and Ohio and Tennessee Valleys through Sunday.
- Much of the Northeast is under a heat advisory until 8 p.m. EDT on Saturday, with heat index values of 95 to 99 degrees expected for parts of New York, northwestern Connecticut and southeastern Vermont.
- High temperatures will climb to the upper 90s° in Washington, D.C., Saturday, potentially breaking the previous record of 95°F set in 1934. As of Saturday morning, temperatures were already in the low 80s.
- More than 100 million people will experience temperatures that are 20 to 30 degrees above average for this time of year.
- It is possible that some monthly high-temperature records will fall, especially in the Northeast.
[Weekend Heat] In case you haven't heard, it will be HOT this weekend. Please take extra caution if you have plans outside today such as wearing loose-fitting light clothing, exercising during the early morning or late evening hours, and staying hydrated!#mawx #riwx #ctwx pic.twitter.com/W0DvYRImtA— NWS Boston (@NWSBoston) May 21, 2022
For most people in the East, the heat wave will be the hottest weather they will have experienced since August 2021. The first heat wave of the season can be particularly dangerous, with higher risks of heat-related illness since people are not yet accustomed to such high temperatures.
- "The abrupt beginning of hot temperatures early in the season after a relatively cool spring brings an increased risk of heat illnesses unless proper precautions are taken for those working or recreating outdoors," the NWS said in a special weather statement.
- "Since many outdoor events are planned this weekend in the region, be aware of the heat, and take extra precautions if you work or spend time outside this weekend. Reschedule strenuous activities to early morning or evening."
- Human-caused climate change is making heat waves around the world more intense and more likely to occur and may be expanding their seasonal timing earlier in the spring and later into the fall.
Editor's note: This story has been updated with new details throughout.