A storm system will be moving through Colorado today and tonight with another one quickly moving in on its heels during the day on Monday into Tuesday afternoon. The western and northern mountains of Colorado and the entire state of Wyoming will be favored with this first system. There will be just a chance for snow on the northeastern plains of Colorado overnight but some snow accumulations will be possible from the Denver area northward with best chances in Larimer County. Travelers going through Wyoming and over the high mountain passes of Colorado will start to experience snow covered and icy roadways later today. The second storm will favor Colorado over Wyoming with Winter Storm Watches already in place for the I-25 corridor for El Paso, Pueblo and Huerfano Counties from Monday afternoon through late Monday night. Travel will become more difficult along the Front Range later Monday through a good portion of Tuesday. This storm quickly clears out Tuesday afternoon and evening with dry weather and sunshine to start the day across the entire state on Wednesday.
Isolated thunderstorms yesterday along the Front Range from the Palmer Divide southward produced thundersnow and graupel. What is graupel you ask? Well, it can be referred to as many things ranging from soft hail, snow pellets, or tapioca snow. The best description is probably snow pellets as they are white like snow and fall softly unlike hail and are typically small in size. The formation and definition from About.com says:
Graupel forms when snow in the atmosphere encounters supercooled water. In a process known as accretion, ice crystals form instantly on the outside of the snow and accumulate until the original snowflake is no longer visible or distinguishable.
The coating of these ice crystals on the outside of the snow is called a rime coating. The size of graupel is typically under 5 millimeters, but some graupel can be the size of a quarter (coin).
To tell the difference between graupel and hail, you simply have to touch a graupel ball. Graupel pellets typically fall apart when touched or when they hit the ground. Hail is formed when layers of ice accumulate and are very hard as a result.
A springlike storm system will move into the Front Range of Colorado today with convective snow showers expected to develop. The cumulus nature of the storm clouds may generate lightning and with temperatures in the 30’s precipitation would likely fall as heavy “wet” snow or “thundersnow”. Best chances for thundersnow today will be in the foothills and areas west of I-25. Thundersnow is not as rare as people think here in Colorado as it occurs numerous times on an annual basis somewhere in the state due to the mountainous terrain and long snow season. Keep your ears open because you typically cannot see the lightning strike due to the low visibility of the falling snow but the thunder can be heard for miles. Sometimes thundersnow can generate snowfall rates as high as 3-5″ per hour but it typically does not last more than 10-15 minutes.
After springlike temperatures in the 60’s today along the Front Range of Colorado a cold front will move through this evening and cool temperatures by 20 degrees tomorrow. Highs on Friday will be in the lower 40’s with a chance for rain and snow. 60 degree temperatures will not be seen again for awhile as the weather pattern continues to be active into early next week with multiple disturbances moving through. A major snow storm may be brewing for early next week but the storm track remains uncertain at this time.
March is typically the Front Range of Colorado’s snowiest month of the year. Some of the biggest snow storms have occurred during the month of March in Denver history with the last one in 2003 which resulted in the most snow ever for the month with 35.2″ in Denver. We will certainly need some snow this month to help make up for the lack of snow for the winter season so far and help alleviate the wild land fire threat which rears its ugly head every spring. The likelihood of above normal snowfall is looking low this year with near normal snowfall expected this month for most locations along the Front Range. Below is the snowiest months in order for the Denver Metro area:
1. March – 11.7″
2. November – 10.7
3. April – 9.1″
4. December – 8.7″
5. January – 7.7″
6. February – 6.3″
7. October – 4.1″
8. September – 2.1″
9. May – 1.3″
10. June – Trace
March being the snowiest month may not surprise many, but April coming in at number 3 should raise some eyebrows. The snow typically does not stick around very long in April but it sure can snow with heavy wet branch breaking snowfall and high water content typical of April storms.
High pressure over the southwest is resulting in above normal temperatures across Colorado today. Across eastern Colorado temperatures warm into the 60s. Normal high temperature in Denver for this date is 50, for Colorado Springs 48, and for Pueblo 54. Mountain areas will see highs in the upper 30s to low 40s for the next several days, also above normal. Across western Colorado, highs in mid to upper 50s, with Grand Junctions normal high for this date of only 43.
Although Colorado is seeing quite mild temperatures, a very cold arctic air mass is just north of the state, with Gillette, Wyoming having a low temperature this morning of 12 degrees. That cold front is expected to stay north of Colorado however, with above normal temperatures continuing through Thursday across the state.
The coastal areas of California including parts of the San Francisco and Monterrey areas experienced some snow Friday night. The snow did not stick at sea level but there were flakes in the air. Minor trace accumulations on elevated surfaces occurred at the higher elevation neighborhoods but melted as it reached the ground surface. This was the first snow for these areas of California since February 5th 1976! Many Bay area residents expected more snow and were let down that they did not get to go sledding but it created quite a stir with local media and residents. As the storm moves southward today there will be snowfall in the Los Angeles foothills down to 1,500′ and possibly bringing record low temperatures to the area overnight. More information about the rare California storm can be found at the Los Angeles Times.
Cold temperatures in the upper teens to low 20s combined with widespread areas of fog resulted in perfect conditions for the formation of rime ice. Rime ice is formed when the droplets of water in fog freeze on objects, as was seen across the Metro Denver area this morning. Visit the gallery to see images of this mornings rime ice, and feel free to send additional images to us, we would love to add more images to the gallery!
A strong cold front moved through the southeastern states yesterday the 24th of February spawning tornadoes in parts of Missouri, Arkansas and Tennessee. Strong winds were reported in a number of states with numerous trees and power lines downed with reported straight line winds of up to 80mph. Hail was reported but the largest stones were 1.5″ in Homer , LA. February is a little early for the severe weather season but it is not uncommon to see some severe storm activity during the month. What may be a little more rare was the large swath of land that was affected with 8 states in total reporting wind tornado or hail damage. Some images from the severe weather can be seen from WSMV TV Nashville at: http://www.wsmv.com/slideshow/weather/26991711/detail.html