Weather Extremes to Fade After This Weekend
April 26, 2012; 10:32 AM
Thursday, 11:50 a.m.
As has been the case for a couple of months now, we're in another period of extreme weather. A more descriptive term would be 'highly amplified'. Just look at the afternoon 500 mb forecast, and you can get an idea of why:
Underneath that strong upper-level ridge over the Plains, it has been very toasty! For instance, look at the high temperatures from Wednesday:
Despite it being Texas, it's early even for them to be over 100! Many of these highs weren't just records for the date, but record highs for the month of April! It was 91 all the way in Omaha, Neb., and 90 in Des Moines, Iowa! this kind of heat will be fading this weekend as cooler air presses in from the north, and by Sunday, only the lower Mississippi Valley over to Georgia will be more than a handful of degrees above average for late April.
In contrast, on the other side of a front it struggled to get to 60 in Chicago, a level they won' t reach again until early next week. That's well below the average high of about 63 or 64 degrees right now, and that's only the western edge of the true chill. Early in the week we saw nearly 2 feet of snow atop Laurel Summit in Pennsylvania, setting the stage for what has been a cool week throughout the eastern Lakes and much of the Northeast.
That cool is trying to get erased today, only for another strong cold front to come blasting through the region later this afternoon and tonight. Tomorrow will be much below normal once again throughout New England and New York down into at least northern Virginia, and that will extend westward over the Appalachians into the Ohio Valley and Midwest.
Then another disturbance coming out of the Rockies will cause rain to break out in the Dakotas tonight. That area of rain, with embedded thunder on its southern side, will head steadily to the east and southeast tomorrow into Saturday, spreading rain into the Ohio Valley, then into the mid-Atlantic states later Saturday and Saturday night. The sad part is that it may not be all rain once again. The air north of the track of the storm will be quite chilly, cold enough to support snow, especially in the higher terrain of central Pennsylvania. It may stick to the roads very well, but snow is snow, and to be seeing two separate snow events in five days in late April is a rare feat indeed!
Before that moisture even gets into the mid-Atlantic, it will be clear and very cold with a hard freeze tomorrow night across much of the interior Northeast, including northern Pennsylvania and New York state. And it may not even be the coldest night in the pattern! Yes, once the storm exits, high pressure will approach from the Midwest, leading to a clear, calm, very cold night Sunday night:
This time around, the freeze may extend into West Virginia, even northern parts of Virginia!
And if that's not enough, there's an area of showers and thunderstorms worth at least a peek in the Caribbean:
Computer forecasts have been all over this thing all week long, now, and while they don't really develop it, they do spit out a lot of precipitation. The thing going for it is the early-season warmth of the water. The strike against it, and it's a big one, is the upper-level shearing winds from the southwest that are just too strong to allow for development. Nevertheless, we are little more than a month away from the official start of the Atlantic hurricane season. Check out our 2012 Hurricane season outlook online:
http://www.accuweather.com/en/weather-news/accuweather-2012-atlantic-hurricane-forecast/64215
Next week, though, the troughs and ridges will flatten out, and the prospects for warmer weather returning to the East look promising as the week progresses.
The views expressed are those of the author and not necessarily those of AccuWeather, Inc. or AccuWeather.com