Tuesday, 11:30 a.m.
There's no debating the fact we are now in the transition season, leaving the heat and humidity of summer behind and bracing for the cold, wind and snow of winter to come. As the radiation balance in the Northern Hemisphere becomes more and more negative, it becomes much easier for cold air masses to grow in the high latitudes. It won't be long, now, before the snowcover charts of the Northern Hemisphere show dramatic changes:
With the upcoming shot of cold air now on the doorstep of Montana, it won't be long before the air will be cold enough to support snow in parts of the northern Rockies. In fact, if you believe some of the models literally, then there will be snow on the ground by Friday night in parts of Minnesota and into Ontario! Here's the GFS version:
The European model is even more bold, with snow on the ground in parts of North Dakota and northern Minnesota!
While that may be stretching things a bit, and certainly getting a big jump on the season, it highlights the importance for 'warministas' like myself to make the most of the warmth that will precede this hard-charging cold air outbreak!
Today is the day to do it in Montana and the Dakotas, where sunshine will boost temperatures into the 70s, even the 80s over southeastern Montana and parts of the Dakotas. A few spots may touch 90 degrees in western South Dakota and western Nebraska! Tomorrow, that warmth will prevail across central and southern Minnesota into Wisconsin, south and west into most of Nebraska and Colorado.
Meanwhile, the warmth coming back into the East today is being accompanied by clouds and some rain. There's also a very distinct surge of tropical humidity, with dew points already up to 70 in central Maryland and the southern half of the Delmarva Peninsula. Tomorrow, there will be some breaks of sun, but look at the strong ridge sitting just off the coast:
That all but forces all of that warmth and humidity to drive straight north! When you reduce the rain, start the day with temperatures well into the 60s to near 70 degrees, and then add in some sun, then it should be quite easy to push temperatures past 80 east of the Appalachians and into parts of southern New England.
Even on Thursday, it will remain warm, as the upper-level ridge won't weaken all that much, so with more drying of the atmosphere, a little more sunshine and a decent wind out of the west and southwest, temperatures will again surge to 80 or better.
It'll do the same on Thursday in the Ohio and Tennessee valleys; by Friday, the cold front will be approaching from the west to take out the warmth for good.
The front will slow later Friday and Friday night into Saturday as it tries to move over the mountains, Initially, showers will only skirt the I-95 corridor going into Saturday, and with any appreciable sun, it could still get into the 70s. By Sunday, though, the front will have moved through, and the gig will be up. Look at the projected temperature anomalies for Sunday across the country:
I guess it may be time to put the hammock away, take the air conditioning units out of the windows and find my cold weather cycling gear, buried somewhere in the closet or attic!
Cold and dry weather is the rule across the country right now, but the respite from stormy weather will be brief. A new storm taking shape Friday in the Mississippi Valley will spread more rain, ice and snow over the eastern half of the country going into the weekend.
In the wake of the feature bringing snow through the mid-Atlantic and southern New England today, there will be a nice little period of cold and quiet weather for most of the country until the next storm begins to take shape over the southern Plains and Mississippi Valley late Friday into Friday night.
Winter doesn't officially begin until Dec. 21, but there's plenty of evidence of winter already fully in force around the country. The rest of fall will largely be cold in much of the nation before it tries to moderate later next week.
One fast-moving storm will dump snow, ice and rain over a wide area from Arkansas to southern New England this afternoon and tonight. Another will follow for later in the weekend.
Two separate features will zip across the eastern half of the country by the start of the weekend, generating rain, thunderstorms, ice and snow before it quickly dries out to start the weekend.
Three storms over the next week will dump snow and ice over a large portion of the country, and with frigid arctic air firmly in place around the country, it would appear winter is here to stay.