Friday, 11:55 A.M.
Summer unofficially gets underway this weekend with the Memorial Day holiday. Many are taking advantage of the time to make it a four-day weekend, and the weather will play a pivotal role in any plans or activities over the next few days. For some, the weekend will be nearly a washout. In other areas, the weather will nearly perfect from start to finish, while in other locations, parts of the weekend will be good, while some other parts are not so nice.
Starting west and coming east, the Northwest will see a couple of cold fronts slice through the area. The first of these will pass through with a few scattered showers and a couple of thunderstorms this afternoon into tonight before working into Montana tomorrow. After a nice day tomorrow in the region, clouds will increase again Sunday ahead of front number two, one that will bring showers into western Washington and northwestern Oregon later in the day and at night. Most of those showers will be few and far between on Memorial Day in the region, but it will turn a little cooler.
To the south, where after a heat wave the week before, California has been much cooler this week with the upper-level low rolling slowly into and across the state. As it wobbles off to the east this weekend, the region will steadily warm, and by Sunday and Monday, it will be heating up once again. Look at the projected temperature anomalies for the holiday itself:
You'll note the cooler-than-normal forecasts for the southern Rockies and southern Plains. That's directly tied to the slow-moving upper-level low. As it inches to the east, there will be plenty of clouds along with showers and some thunderstorms from central and western Texas back into New Mexico. Look at the projected 84-hour total precipitation from the 12z NAM model:
It should be noted that much of this rain is going to fall over an area that is extremely dry, so even though it might 'ruin' outdoor plans in these areas, I suspect most are willing to take the rain while they can get it.
Over the top of all this wet weather will be just a few showers and thunderstorms from the northern Rockies into the northern Plains. With the source region for the air mass in this area no longer cold, the air behind any front isn't cold. Therefore, ahead of any front, it will be warmer than normal, thus the warm forecast for the holiday weekend.
Pop-up thunderstorms will be the rule in Florida and up into the Southeast Sunday and especially Monday. Going into the weekend, the upper-level ridge will be too strong to allow that to happen. Otherwise, it will be pretty toasty, and this may be the one area of the country where it will truly feel like summer weather has moved in.
In contrast, the Northeast will struggle to get warm. With an upper-level low anchored over southeastern Canada and the northwestern Atlantic, cool air will hold its ground through tomorrow and into Sunday across New England. Along with the cool air will come plenty of clouds and showers, further helping to keep day time highs well below normal. Here's the GFS ensemble 500mb heights and anomalies forecast for Sunday evening:
That leaves the Ohio Valley and the mid-Atlantic states, where it will get progressively warmer this weekend. And, for the most part, it will be dry, and the weather will be ideal for outdoor plans. If I have to pick a weekend-long 'vacation' spot, it might be somewhere from Richmond to Columbus - lots of sunshine, warm afternoons, low humidity, and no rain. Just about perfect for anything you'd want to do outside!
A storm heading for the Midwest this afternoon and tonight, while generating snow in parts of the Midwest, will push warm air ahead of it, with little cold air behind it reaching the East.
A snow storm affecting the central Plains and Midwest into the Great Lakes this afternoon into tomorrow night will be followed by the first of two arctic outbreaks around the country before Thanksgiving.
Winter is six weeks away, and there will be a couple of signs this week of the approaching season as a storm develops on the western Plains and heads through the Great Lakes.
A warm pattern is setting up for much of the nation next week.
Tropical moisture associated with the one-time Hurricane Patricia will bring heavy rains to many areas east of the Mississippi Valley between now and Wednesday night.
Patricia, the strongest hurricane on record in the eastern Pacific, will make landfall this evening in Mexico. It will spread torrential rains into East Texas, and impact the weather all the way to the Northeast next week.