Tuesday, 11:00 A.M.
Welcome to 2013! Have you made your New Year's resolutions yet? Let's see, lose weight, eat better, get in shape, save more money, get out of debt -- I bet at least one of those things is on your list, no? They will undoubtedly top the list of most Americans as we wade into the chilly waters of January.
Speaking of chilly, it is every bit that across the Lakes and Midwest into the northern Plains this morning. Here's a look at the early morning lows:
It's really the first time this winter we've seen this much cold this far south in the nation, and it will have some interesting implications in the pattern for the rest of the week. Still, in the end, this will only be a brief period of cold before much of the nation from the Rockies on east turns much warmer this weekend and especially next week.
The cold will come in a series of waves as we drain the arctic of that vast reservoir of cold that had been in Alaska and northwestern Canada for a significant portion of November and December. The first thrust of arctic air is aimed largely at New England. Look at the latest NAM 850-mb forecast for tomorrow morning:
Whatever warming or recovery there is tomorrow across the Midwest, and into the Ohio Valley, mid-Atlantic and Northeast on Thursday, will be trimmed back or, at the very least, stalled Thursday into Friday by another piece of arctic air coming through the pattern in the wake of a weak storm and attendant cold front. Here's what the NAM surface map looks like Thursday afternoon:
If you look at that map carefully enough, it's not like the southern and central Plains and lower and mid-Mississippi Valley will turn dramatically warmer. A 1036-mb high over eastern Colorado and Kansas will set up a strong temperature inversion, one that with a lack of wind will be hard to break with the low sun angles prevalent at this time of the year.
There will be a couple more waves of low pressure that will progress from west to east across the northern half of the country late this week through the weekend. However, instead of seeing it turn colder behind each system, by the weekend, there won't be a lot of cold air left. Look at the projected temperature anomalies for Monday:
The key to the pattern going forward will be the pressures across Canada. Instead of seeing strong high pressure coming through Alaska and the Northwest Territories into the Prairie Provinces, the pressures will be much, much lower. And when the pressure is low across Canada, that leads to a lot of south to southwest or west winds, a wind that downslopes off the Canadian Rockies. Such a wind warms and dries upon descent, and leads to a push of much warmer air. We're already seeing that across Alberta into parts of Saskatchewan, with temperatures in the 30s in many places now.
It will take a while for that surface high over the plains to fade and allow for stronger winds to stir up the atmosphere this weekend, but in time it will erase the cold, and the result will be a warm-up next week that will extend from the Rockies to the East. The projected GFS ensemble 7-day means for next week:
Because of the snowcover in place from the Ohio Valley to the Northeast, that warm-up will initially be pretty slow, but it should gain some steam as the week wears in. Given the chill of the next several days, you might well consider it an early January thaw.
Much of the country from the Plains to the East Coast will have several more days of very cool weather. Meanwhile, Odile is threatening Arizona and New Mexico with flooding rains later this week.
A strong storm in Quebec combined with a very large high near Montana will result in sweeping changes across the Ohio Valley into the mid-Atlantic and Northeast in the next 24 hours.
The latest surge of heat and humidity into the Midwest will spread to the East tomorrow but be trimmed back to the South later this weekend by the passage of a cold front.
Summer's heat and humidity will still have a period of time to sizzle the rest of the week into the start of the weekend, but a fall-like air mass will invade the northern Plains and Midwest this weekend.
Even though fall is but three weeks away, summer heat and humidity will have a full run this week from the Plains to the East Coast.
The steamy weather from the Mississippi Valley to the East Coast today will be trimmed only slightly behind a cold front tomorrow into Wednesday. It will heat up again late this week.