Monday, 11:45 a.m.
Low pressure is organizing over the western Gulf of Mexico, and it has already brought some snow through parts of New Mexico and West Texas over the weekend. The moisture is finally pulling away from the Southwest and the southern Rockies, and most of West Texas is now just cloudy and cold. Overnight and this morning there was some snow and ice in central Texas, but that has largely ended. Now the ice is impacting central and northern Arkansas and southernmost Missouri, with patches of snow farther north. Here's the late morning snow/ice/rain radar:
Since I had a chance to write last Thursday, amazingly, little has changed with the storm. Timing remains a Tuesday into the Southeast/Wednesday run the Eastern Seaboard track, with rain the primary form of precipitation anywhere near the track of the storm. The one main change is the track itself, not so much the timing. The track is now clearly going to be across the Southeast to the eastern Carolinas, then more north-northeastward into New Jersey and western New England in the end. The main reason for that is that the northern and southern branch systems will be phasing. Here's what that looks like from the NAM model vantage point tomorrow evening:
There are actually three pieces to this puzzle if you look carefully. The first is working its way across Lake Superior, pulling a cold front through the Great Lakes. The second is the feature rolling across Louisiana, the one drawing the storm out of the Gulf of Mexico into Georgia. However, there's a third piece, one coming down the back side of the upper-level trough out of the northern branch into Missouri.
As storms go, this one will become a prolific precipitation producer. By Thanksgiving morning, several inches of rain may well have been dumped on some areas from the storm. Here's the NAM model projected precipitation totals:
MUCH of that will be rain. But not ALL of it! On the northwest flank of the storm, we are already seeing snow and ice in parts of Missouri and Arkansas, but it's relatively light. There will be heavier snow and ice accumulations, though, from parts of north-central Tennessee into eastern Kentucky, West Virginia, and eastern Ohio into western Pennsylvania and western New York state. Even in many of these areas, it won't likely be entirely snow! There will probably be enough warming aloft for a time to change some of the snow to sleet and freezing rain, if not entirely rain for a time.
Even as the precipitation shield advances northeastward tomorrow and tomorrow night on the front side of the storm, there will be some resistance to the warming in the low levels of the atmosphere that will result in some snow and ice from at least Pennsylvania northward, if not even farther south. Here is the very latest projected snow accumulation forecast:
Obviously the farther north you go, the higher the snow totals ought to be and will be, as the deepening storm is able to wrap greater quantities of water deeper into the cold sector of the storm.
That trailing max tomorrow evening coming into Missouri will cause some back end issues to the storm. I would guess that West Virginia would be the target zone for a last minute dump of snow tomorrow night and early Wednesday, though the latest NAM model hints at it starting farther south. It should then track northeastward across northern Virginia into the Susquehanna Valley, and then eastern New York state. It may add a few inches to the snow totals in a relatively narrow band.
Meanwhile, on the eastern flank of the storm, there will be a gale wind that will transform a cold, icy air mass into a tropical one in a matter of hours, pushing temperatures into the 60s along the Delmarva Peninsula right up into parts of southern and eastern New England. Then, once the storm rolls by, gale force winds will send temperatures plummeting right back down to those icy levels Wednesday night, and could mean a flash freeze on some areas of the mid-Atlantic and parts of New England.
Once the storm exits, it gets cold but quiet once again. Temperatures will be well below normal throughout the South and East Thanksgiving Day:
In fact, with a clean sweep across the South, the air mass will clearly be colder there than this past one was, though in the mid-Atlantic states and New England, it may 'only' be similar to what we are coming out of today!
Two systems will delay the onset of warm weather in the Ohio Valley and the East over the next week or so, but then it should get warm all across the country heading into the Memorial Day weekend.
A turn to much colder air over the Northeast and mid-Atlantic states will set the stage for a rain and snow storm later this weekend before it turns much warmer later next week.
It's warm now, but will turn much colder this weekend, with a storm threat later Saturday into Sunday. Warmth will return by the second half of next week.
Though it is cold now east of the Mississippi, with a couple of opportunities for snow into the weekend, a blast of warmth is due for much of the country east of the Rockies next week.
Warm air will once again surge eastward from the Plains to the East Coast this weekend and early next week. A strong storm next Tuesday and Wednesday will then be followed by colder air later next week.
A storm in Southeast Texas will generate severe thunderstorms this afternoon and tonight, and some wet snow on its western flank as it heads into the Ohio Valley tomorrow.