Pattern Change Busts in the West, and a Major Blizzard Back East

The big weather news is not currently about winter storms impacting the West. Rather, news headlines are focused on a Nor'easter (blizzard) forecast to slam the Mid-Atlantic and New England states. Given the storm's potentially high impact, I will discuss more details about this event in a moment. 

First, I don't have good news for those expecting a weather pattern change in the West. For weeks, extended range models were generally indicating a retrograding long wave pattern toward the end of January. I hoped a consolidated ridge would amplify further west over the Pacific, allowing for an active storm pattern over the Western states. Unfortunately, it now appears likely the ridge will remain too close to the West Coast, blocking moist Pacific storms. Here's the latest GEFS forecast upper height anomaly average for the first 10 days of February: 

There's broad consensus among the extended models that this pattern will dominate, even moving into the second week of February. Not good at all. Now, there is some westward shift in the major features expected, just not enough. Notice the ridge height anomalies offshore now extending inland to the Great Basin. Lower height anomalies are confined to the north/central part of the country. This pattern often leads to "clipper" systems tracking across the Northern Plains and upper Mid-West regions (minor snowfalls). 

The flow aloft over Utah and interior West, will come from a drier and colder northerly direction. Don't expect much warming here in Utah, but rather seasonable temperatures. A weak upper trough will move through from the north on Wednesday. Coming from an over land trajectory, this system will be moisture starved. Some models show a chance of minor snow accumulations, likely under 1". The NBM (model blend) forecast snow amounts on Wednesday look reasonable:

Not impressed? You shouldn't be. We need a lot more mountain snow if we want to end the season with just average snowpack. If the pattern doesn't improve in the coming weeks, our reservoirs are likely to end up in worse shape this summer than last year. 

Could the pattern become favorable for snow later in February? Short answer: I don't know. Extended range models are demonstrating poor consistency, and signal weak anomalies that don't point to a particular pattern later next month. 

Given the lack of weather in the West, let me discuss the Nor'easter that is forecast to slam parts of the East with blizzard conditions this weekend. Here is the water vapor satellite view of the storm, in the early phase of developing Friday afternoon:

The surface pressure is forecast to drop sharply tonight through midday Saturday, as the system rapidly intensifies. This storm fits the definition of a "bomb cyclone" (sea level pressure falling 24 mb in 24 hours). Some models show a sub 970 mb surface low just to the southeast of Boston, MA Saturday afternoon:

If pressures deepen anywhere near this low, there will be coastal flooding, and high winds coinciding with the heavy snow band shown above (blues/purples). Blizzard conditions are almost certain for near coastal areas of the Mid-Atlantic states to New England. The National Weather Service has blizzard warnings and numerous other hazard statements in effect for the region:

Northeasterly wind gusts will peak in the Mid-Atlantic states late tonight and in New England on Saturday. Here are the expected wind gusts near the peak of the storm's strength on Saturday, 60-70+ mph from Long Island to New England. High winds combined with heavy snow will lead to widespread power outages from New Jersey to Maine.

Snow amounts are forecast to be rather extreme, but not unprecedented. The heaviest snowfall across the region in years, for sure. There will be a tight snowfall gradient from lighter amounts to the highest amounts, possibly exceeding 2 feet. Greatest uncertainty of forecast snow amounts are from near Dover, Delaware to New York City (up to a foot possible). A slight shift in the track of the low could bring higher or much lower snow amounts within that corridor. Highest confidence in snow amounts are from Long Island to the coastal New England states. Here are the potential snow totals through the weekend:

Yes, you're reading that right. Portland, Boston, Providence, New Haven, and Montauk/Hamptons in Long Island could all see 2 feet of snow. Local amounts up to 30 inches are possible, especially at hill top locations like Worcester, MA. Snow of this magnitude has occurred in the past, but amounts over 30 inches are rare. This may not be a record-breaking storm, but certainly memorable (or historic) given the combination of hazards causing damage, travel impacts, and outages.