Wednesday, 11:30 a.m.
We're now officially four weeks removed from winter, but we are still struggling to escape the clutches of the winter season. The week opened with a dumping of heavy snow on Colorado. Yesterday, the snow was simply farther north, centered on Wyoming and western South Dakota. Today, it's breaking out anew over Colorado. While this storm may not be as prolific of a snow maker as the storm Monday in Denver, it's still going to be plenty cold enough for at least several inches by the time the storm pull out and away from the Rockies and across the central Plains later tonight and early tomorrow.
Not only will it snow, but it will be windy and exceptionally cold by April standards. Winds will be clocked upwards of 40 miles an hour this afternoon and tonight over eastern Colorado into Nebraska and Kansas, with temperatures generally in the 20s at the height of the snowfall. That means a snow that can be moved about fairly easily, so a few counties in Colorado are under a blizzard warning, too!
North of the storm, the large high over northwestern Ontario that is keeping areas from northern New England to the northern Rockies colder than normal will split in two, with the larger piece heading into Quebec tonight, while a small chunk drops into the northern Rockies behind the departing storm. Here's the projected surface weather map for tomorrow morning from the 12z NAM model:
And here's the latest snowfall projection through late tonight:
Quite the prolific storm for so late in the season!
On a quick side note, not all is necessarily bad with this late season snow. For one thing, it's flat out much-needed moisture for an area suffering through a multi-year drought. At the very least, it will be very helpful in the short term to supply moisture for crops and plants, though any turnaround in the pattern could quickly reverse the short-term benefits. With lower-than-normal temperatures, the evaporation rates are simply slowed across the general area, which means this moisture won't just vanish in a couple of days.
Farther east, the problem will be heavy rain and strong to severe thunderstorms. Look at the severe thunderstorm outlook for the rest of today and tonight from the Storm Prediction Center:
Dew points are near or over 70 all the way up into central and eastern Oklahoma at this hour, more or less rocket fuel for the development of thunderstorms this afternoon and tonight. As the storm develops late this afternoon and tonight, it will shove that warm, humid air back to the north into Missouri and Illinois, resulting in strong thunderstorms with the threat of hail, damaging winds, isolated tornadoes and, of course, heavy, heavy rain.
As the storm deepens and rolls up into Wisconsin tomorrow afternoon, it will drive strong thunderstorms across the Mississippi Valley into the western Ohio Valley and western Tennessee Valley in the afternoon, sweeping eastward across both areas and the Deep South tomorrow night and early Friday.
The storm will cross the Great Lakes tomorrow night and Friday morning and begin to weaken. Oh, there will still be some snow on the northwest flank of the storm, and there will still be some showers and thunderstorms marching over the Appalachians into the East later Friday and Friday night, but the overall intensity of the rains and their embedded thunderstorms will be weakening over time.
Lost in all of this is the fact that a few places are seeing record heat, like in Florida yesterday, with a few places over 90 on Tuesday. Winter. Spring. Summer. All on the U.S. weather map, making it a land of weather extremes.
A pattern of extremes is once again unfolding across the country over the next week, with two shots of cool air interspersed with intense heat.
Despite the heat over the central and southern Rockies this week, an amplified pattern means cool air will dominate in much of the country for the rest of July.
Heat will resurface over the eastern Rockies and Plains this weekend and early next week, but the warming in the East will be much slower.
In the wake of the deep upper-level trough over the Great Lakes to the Tennessee Valley, a strong upper-level ridge is poised to blossom over the Rockies, one that will bring on the heat this weekend into the start of next week.
Beyond the big chill now engulfing the Plains, it will turn warmer and more humid in the East back into the Ohio Valley. The heat will be turned up in the northern and eastern Rockies and northern Plains into the Midwest this weekend into early next week.
The West is very hot, while it is turning much cooler in the Plains and Mississippi Valley. Before the cooler air reaches the South and East, there will be a lot of showers and thunderstorms, including severe weather and flooding.