Monday, 11:55 A.M.
All in a five-day span. We have the extreme cold now. The super storm will develop off the Southeast coast tomorrow, and then it will deepen explosively tomorrow night into Wednesday as it charges from east of Hatteras by Cape Cod, then toward Nova Scotia. But by week's end, the storm will be gone, the cold will be exiting, and much milder air will prevail from the middle and lower Mississippi Valley to the East Coast. Just your typical spring week!
The cold is leaving its mark over the eastern half of the nation right now. The past two mornings have reached 26 below and 25 below, respectively, in International Falls, Minn. The amazing part about this morning's low was that it was four degrees ABOVE the record of 29 below, set in 1974! Otherwise, it would have been the coldest for so late in the season. If they can somehow drop to 22 below the next two nights, that would then become a new mark for the coldest so late in the season for them.
Meanwhile, around the edges of the cold we find a corridor of moisture over the northern Gulf of Mexico stretching into northern Florida. This area of clouds, rain, and even some thunderstorms is largely off the Gulf Coast, heading due east, and by late tonight, low pressure will be organizing off the northeast coast of Florida. If you look at the 12z March 24 NAM 700 mb forecast for tomorrow morning, you can pick out the two main features we're going to be dealing with as this storm develops. The first is a relatively weak upper level trough darting across the Southeast, getting the storm to initially develop:
Trailing this is a much stronger upper-level trough slicing across the Great Lakes into the Ohio Valley, and it will be tied to another arctic cold front. As the trough moves through the Midwest this afternoon and tonight, it will wring what little moisture there is in the atmosphere out of it, generating a little snow. The same is true late tonight and tomorrow from the Great Lakes and Ohio Valley to the Appalachians, with most places outside of the mountains and away from the Lakes struggling to get more than an inch of snow.
But as we approach the end of the day tomorrow, that trough will approach the East Coast, and the arctic air associated with it will be like a shot of adrenaline to the offshore storm, causing it to deepen rapidly tomorrow night. That will help to squeeze the atmosphere a little harder so that portions of the Carolinas and Virginia up into Maryland, Delaware, southern and eastern Pennsylvania and New Jersey can pick up a little snow. Again, it won't be a lot, and much of it will melt on road surfaces.
The place that remains most vulnerable to getting hit with a lot of snow is southern and especially eastern New England, and that may include the east end of Long Island. Cape Cod and Downeast Maine are likely to bear the full fury of the storm, with gale force wind and heavy snow. There is still the potential of a foot or more of snow, with massive snowdrifts thanks to winds blowing at 40 to 50 mph and higher with and behind the storm in these areas. In addition, extensive beach erosion and coastal flooding will occur, and power outages are likely. This is what the European model is portraying Wednesday afternoon:
That's about a 950 mb low, equal to a Category 3 or 4 hurricane! What a wild storm this will end up being. Now, if the storm tracks even 50 miles farther west, then much heavier snows will also spread farther west across New England. Let's hope that doesn't happen.
Behind the storm, the blast of arctic air pouring through the Midwest tonight and tomorrow will drill all the way to the Gulf Coast and the Southeast tomorrow night and Wednesday, with frost possible right to the I-10 corridor.
Look at the 500mb height anomalies with this beast Wednesday morning:
By Friday morning, just 48 hours later, that trough is long gone:
It's that dramatic of a change, and as the trough races out to the northeast, it will take the last of the bitter arctic air with it. There are some differences amongst the models with regard to the timing of the next storm cutting across then central Plains and into the Midwest and then Upper Great Lakes, but they all agree that it will pull in a much milder air mass from the central and southern Plains across the Mississippi Valley and points downstream. And that means a milder day with April showers, rather than January snows!
It will not be with too much sadness most of us will say 'good-bye' to the cold and snowy weather pattern. There will still be some bouts with chilly air next month, and probably some snow, most likely relegated to the northern tier states and the higher elevations of the Northeast. But I think we can finally say that after Wednesday and Thursday, the back of winter will FINALLY be broken!
The heat and humidity will be erased from much of the East later this week, but warmth will spread from the Plains eastward over the weekend. The tropics could still play an important role in the weather along the Eastern Seaboard this weekend.
A dominant ridge will keep it hot from the Ohio Valley to the East into next week, while the disturbance north of Cuba is slow to develop as it approaches the southeastern Gulf of Mexico.
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.