wxgeek's weather-Warm, Then Breezy, Then Cold and Snowy

Enjoy the warm weather while it lasts, change is coming. Upper ridge that was centered over CA early this week will be passing over CO today, hence the unseasonably warm weather today. High temps 15-20 degrees above average most locations in the state today. As upper ridge passes, we will become more under the influence of a deep upper trough that will move down along the West Coast later this week. Thus, slightly cooler temps, a few more clouds and increasing southwest winds aloft on tap for Thursday. Winds aloft will mix down to higher elevations of the mountains and foothills to create breezy southwest winds of 10-25 mph Thursday. Conditions will be close to red flag conditions during the day. Winds will increase further on Friday, with southwest winds of 25-50 mph possible Friday morning into Friday night. RH values will be close to Red Flag criteria, so fire danger will be high to critical on Friday. Winds could also cause power outages and downed trees. Strong winds should abate after cold front passes early Saturday morning.

Upper trough begins to move east on Friday, and models consistent with a split of the energy. Northern branch will create a good early season snowstorm/near blizzard over portions of MT, WY and ID on Friday. Models are now putting a little more energy into the southern branch, which will cause the system to move into CO a little slower. Some precip will move into western CO, west of Vail Pass, Thursday night with snow level 8000-9000 ft. Primary cold front will move into western CO late Friday and move into eastern CO by early Saturday morning. The new development on the models is a surface low forming over southeast CO on Saturday, which will aid in some upslope flow in eastern CO Saturday. The mountains west of the Divide will get the brunt of this system, but now looks like precip will be likely Saturday into Sunday for areas east of the Divide as well. Precip will develop over the foothills early Saturday morning and spread east into the Plains by mid Saturday morning. Snow level initially 6000-7000 ft Saturday morning, but will lower to Plains level by Saturday evening. Periods of snow may continue into Sunday afternoon. Still does not look like a big snow producer for areas east of the Divide, but we should see some light accumulations between Saturday morning and Sunday evening. Currently looks like 6-12 inches for mountain areas west of the Divide, 1-4 inches for the foothills, and 1/2-2 inches for the Urban Corridor and Plains. Precip will likely be a mix of rain and snow for the Urban Corridor and Plains Saturday turning to all snow by Saturday late afternoon/evening. The big change will be temps. After the front passes, high temps only expected in the upper 20's to low 30's Saturday for foothill areas, and mid to upper 30's for the Plains. Lows in the teens Saturday night, with high temps Sunday in the low to mid 20's foothill areas, and upper 20's to low 30's Plains. Precip should end by Sunday evening, with clearing skies and warmer temps to start next week. Roads could be slick at times Saturday into Sunday afternoon.

Next chance for precip according to long range models is Wednesday/Thursday next week, but not looking terribly significant at this point. As our weekend system moves east, models are indicating a chance for a late season severe weather outbreak Sunday and Monday from the Great Lakes south into TX and the lower Mississippi Valley. Severe thunderstorms with the possibility of strong tornadoes looks possible for this region Sunday and Monday. Fall severe weather events are not that uncommon, as you still have the ingredients like Spring with cold air from the north clashing with warm moist air from the Gulf.

Noreaster is battering the mid Atlantic coast today, with rain, sleet and snow accompanied by strong northeast winds impacting MD, NJ, DE, NY and CT. Rain/snow line is appx 50-100 miles inland, but could move back to the coast later today and tonight. Surface low currently off the NJ coast will move slowly north to Cape Cod on Thursday, pushing the precip mostly into New England Thursday. Storm will exit the U.S. areas Friday.
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