Blizzard, Severe Weather on Tap This Week
Feb 27, 2012
Blizzard conditions, severe storms, ice and unseasonable warmth – oh my!
An intensifying low pressure system will move out of the Rocky Mountains and into the northern Plains on Tuesday, bringing with it blizzard conditions, mixed precipitation, and the threat of severe thunderstorms.
Counterclockwise winds around the low pressure system will draw cold air from Canada while warm moisture air surges north from the Gulf of Mexico ahead of the storm. The northern part of the storm will have enough cold air and moisture to produce heavy snow. Winds will increase and the storm will deteriorate into blizzard conditions across the Dakotas and Minnesota by Tuesday night. Snowfall accumulations of a 12” or more are possible across the areas that receive snow. High winds will create blowing and drifting that, at times, will make travel difficult, if not impossible.
Communities south of the snow will see warm air mix into the precipitation, creating mixed precipitation which may fall as sleet or freezing rain. The area of mixed precipitation is expected to develop across Iowa and into southern Minnesota and Wisconsin.
Once south of the mixed precipitation, rain and thunderstorms will occur, likely forming somewhere between Interstates 80 and 70 in the Plains. As of early Monday morning, forecast models are still not in agreement where exactly the severe weather outbreak is possible. However, there is some consistency and confidence that a severe weather outbreak will occur across eastern Oklahoma, northern Texas, and into the Lower Mississippi Valley. The biggest area of uncertainty is Missouri, with some models extending the severe threat north into the Show-Me State.
Thunderstorms are expected to fire sometime during the early morning hours on Tuesday, before sunrise. As the low pressure system moves east, the severe weather threat will increase as moisture and daytime heating increases. Damaging winds and hail appear to be the main threat associated with Tuesday’s outbreak; although several tornadoes are also likely. The severe weather will continue to push east during the overnight hours into parts of Kentucky, Tennessee and northern Alabama and Mississippi. While the storms may lose some punch with the loss of convective heating; wind damage will still be likely with these storms.
|24 hours after the previous map, heavy snow is continuing to fall across parts of the Great Lakes and Northeast while rain fall in the Mid-Atlantic and South. Notice, however, that the severe threat has diminished by this time. Image credit: wunderground.com
On Wednesday, the low pressure system will shift to the east, bringing snow into the Great Lakes region and rain across the south. An area of mixed precipitation is still expected between the snow and rain zones, although the exact track of the storm is still uncertain. Even though the storm is expected to weaken, there is still a chance of blizzard-like conditions across the western shores of the Great Lakes.
By the end of the week, snow is expected to continue east across the Great Lakes and into the Northeast. Here the models diverge; some keeping the snow confined to New York and New England, while others force the snow further south.
Timing for the Eastern US portion of the storm is expected sometime Wednesday night into Thursday. The storm will follow unseasonal highs across the Mid-Atlantic and Northeast with temperatures breaking the 60-degree mark across the Mid-Atlantic and 50’s into southern New England.
As always, be sure to monitor a NOAA weather radio or other local media outlet to rapidly changing weather conditions, watches and warnings. Heed the advice of your local emergency officials and have a plan ready in case of an emergency.