Wednesday 11:55 A.M.
This was supposed to be the day we'd be bracing for a big snow storm in the East! Instead, the only storm is hundreds of miles off the East Coast, is weak, and will have no impact on the weather. Period. Most places away from the impact of the Great Lakes are basking in sunshine, and while it is cold and somewhat windy, the weather as a rule is hardly stormy!
How cold is it? Highs today across much of the mid-Atlantic and Northeast are comparable to the highs seen at the end of December, so we're clearly 6 to 8 weeks ahead of schedule. Feast your eyes on the early morning lows:
As fast as the cold air has swept in over the past couple of days, get ready to watch it steadily exit as we into the weekend. Why? A progressive jet stream flow, that's why! In other words, systems are moving along pretty fast, so the upper level trough that moved into the East yesterday to drove the front both off the Gulf Coast and the East Coast is already moving away from the Eastern Seaboard this afternoon:
Much milder air is moving back out onto the Plains today, and it will spread eastward across the Mississippi Valley tomorrow, and then into the Lakes on Friday, and also help to bring the afternoon highs back up to normal or a little beyond on Friday from the Ohio Valley to the mid-Atlantic states and Northeast.
Most of the country is now very quiet, thanks the sprawling area of high pressure over the lower Mississippi Valley and Tennessee Valley at this hour. This thing is big and strong, which means there area a lot of isobars wrapped around it pretty tightly. And that means cold winds ahead of the high will be traded in for not-so-cold winds on the northwest and western side of the same high. The sun angle is low and its just not up all that long, so the strong inversion present around the high takes longer to break. But break it will, as the next storm will take a couple of days to really gel and bring more and more moisture to bear.
And that storm will come in two pieces, If you look at the upper levels, specifically at the jet stream level, you'll find two features of relevance. Look at the latest, 12z November 13 GFS model forecast for Friday morning:
The first disturbance is rolling through the Northwest toward the central Rockies. As systems go, this one won't be very potent. Oh, there will be some fitful bursts of rain and snow, but not a lot more. The second one is, at that time, scooting into northwestern British Columbia. That one will have a much great impact on the Northwest Friday and Friday night into Saturday with rain, snow, wind, and lowering snow levels.
By the time we reach late Saturday, that disturbance will have crossed the Northwest, and will be driving toward the Great Basin. If we look at the GFS model surface forecast for Saturday evening, you should also be able to pick out the next surge of arctic air coming out of Northwest Canada:
Low pressure will form over the eastern Rockies and western Plains late Saturday, and that low pressure area will head for the Midwest. In response to all of these thing, the flow over the Plains and points downstream will become west-southwesterly, or even southwesterly aloft, and that will help push the warmth out ahead of it.
The air mass won't just be warmer, but it will also be more humid as well. That's not to say we'll be dealing with showers all day ahead of the advancing cold front, but it will get wet, and, at the very least it will get a lot cloudier with time as the flow around the surface high will pull warmth and moisture up from the Gulf Coast Mexico.
Sunday, temperatures should easily reach the 60s into the Ohio Valley, and parts of the lower Lakes as well. And it will get just as mild in much of the East, boosting temperatures just about as far above normal in the means as they are below it today! What a swing in just a few short days!
Enjoy that turnaround in the eastern half of the country. Behind that front? Another blast of cold air will follow. Winter is but weeks away.
Yesterday I was on the road, giving a weather talk to Mrs. Kreger's 6th grade class at Liberty Elementary School in southern Tioga County. It was a treat to travel up and see the students and give them a quick little lesson on how the atmosphere works, why it works, and how I piece together all sorts of information to make forecasts every day for places all across the country:
Thanks to Mrs. Kreger for reaching out to me and inviting me up, and a shout out to the students who were so attentive! Perhaps one of them may step into my role some day down the road!
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