Friday, 11:30 a.m.
Rain pelted Southern California yesterday, with 1.56 inches in San Diego. Since then, the storm has brought a couple of showers and even a thunderstorm through the Phoenix area, and there have been a couple of showers around Albuquerque already today, with more to come this afternoon. Overnight tonight, low pressure will slowly pull away from the Rockies and out across Kansas, as the 12z NAM forecast is implying on its forecast for 6z:
As the storm moves into Iowa tomorrow, there may be just enough cold air in its way over parts of Wisconsin and Minnesota to foster the precipitation ending up as snow, if it doesn't start that way. And while this won't even come close to being a blizzard, several inches of wet snow seem likely, with a portions of extreme northeastern Nebraska, southeastern South Dakota and southwestern Minnesota in line to get up to 6 inches of the white stuff when all is said and done. The vast majority of snow amounts, though, will come in under 3 inches.
We're not done with the storm at this point. The low center Sunday afternoon will drift into the Upper Lakes, but the west-southwest flow aloft will push a lot of moisture into New York and New England, where the air will be pretty cold tomorrow into Sunday morning. That's thanks to a fast-moving low darting into the Maritime Provinces tonight, pulling a weak but noticeable arctic front through the Northeast behind it.
Eventually the primary low will fade as a secondary area of low pressure forms south of New England Sunday night:
This will lead to a secondary area of decent snows across portions of Vermont, New Hampshire and Maine, with localized amounts between 6 and 10 inches through Monday before the secondary low zips out to sea and takes the precipitation with it.
Right on the heels of this system will come another, one that will run into a relatively mild air mass in the mid-Atlantic states and into southern New England. The models are literally all over the place with this next feature, both in terms of speed and intensity, not to mention track. The most realistic view of it is to have a wave of low pressure develop over the lower Mississippi Valley Sunday night, a feature that would then track toward the mid-Atlantic Monday night and Tuesday. That's arguably a little faster than we'd been thinking, and it may mean the air just can't get cold enough to snow with the storm in much of the Northeast, unless you're in the mountains of northern New England, or in the wrap around behind the storm form the Appalachians to the eastern Lakes. It certainly looks to be an all-rain event for most of the I-95 corridor from Boston southwestward.
Slow changes mean more wet weather across parts of the southern tier of states through the weekend, while a faster jet stream will bring more swift changes to the northern tier states.
Odile will bring flooding rains to parts of Arizona and New Mexico over the next three days, but most of the rest of the country will rather quiet weather.
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.