Monday, 11:30 a.m.
Fresh off the long Thanksgiving weekend, I'm looking at a rather weak storm that will bring accumulating snow to parts of the Northeast over the next 36 hours. As storms go, it will be fast-moving, and the upper-level trough is a positively tilted one. In other words, the base of the trough will lag behind the top end of the trough. Visually you can see that here off the NAM 36-hour 500mb forecast for tomorrow evening:
This means the total snow accumulation where it is all snow will at best be a few inches. The air mass ahead of this just isn't all that moist, and it's moving along quickly. Only so much moisture can be handed off from the southern branch to the northern branch feature before it is all pushed aside late tomorrow and tomorrow night. Here's the latest forecast from AccuWeather.com:
Behind this feature, the cold will be slow to exit. The temperature anomaly forecast from the GFS ensembles shows you how chilly it'll likely be Thursday:
In areas where there is still some snow on the ground Wednesday night and it is clear and calm underneath high pressure, temperatures could slip into the teens.
The cold will hang in there through Friday before the last of the reinforcing highs clears the deck. This last one will move into New England Friday and Friday night, keeping it cold there into Saturday while areas back in the Ohio Valley will warm very nicely this weekend.
The rest of the country? Mild, in a word. Not bad at all for the end of November. There's still a general lack of snow cover in much of the nation right now, even though there is plenty just across the border. The most recent snow cover analysis:
The only other weather of note this week will come later in the week as a massive storm in the Gulf of Alaska wobbles closer to the Northwest coast, spreading rain into the northern half of California, as well as portions of Oregon and Washington. It won't be the most prolific of rain events, but it will be mild and wet with relatively high snow levels. They will begin to lower Thursday afternoon and Thursday night as a weak front moves inland. However, the air mass overall in the West will remain mild into and through the weekend.
Over the weekend, with the lack of snow cover on the Plains, it will become quite balmy with many places up into South Dakota and maybe even southeastern Montana reaching the 50s and lower 60s Saturday and Sunday, and 70s perhaps up into parts of southern Kansas. Some of this incredibly mild air will find its way to the East Sunday and Monday, though the departures from normal will not be as large there as they will be on the Plains this weekend into at least the start of next week.
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.