pattern overview 041421
CNN  — 

Winter takes its last breath across most of the US this week, with widespread below-average temperatures and late-season snow in the forecast.

The spring-like temperatures last week are fading this week as a dip in the jet stream moves across the eastern two-thirds of the nation, allowing cooler air to settle in from Canada.

But spring is often known for dramatic changes:

“Volatile, fitting for this time of year is a great way to describe the weather pattern during this timeframe,” said the National Weather Service office in Albany, New York. “After experiencing May-like temperatures on both Tuesday and Wednesday, in a 36-48 hours period, the weather pattern pendulum just like that swings back into winter mode.”

Cool and snowy end to week in Northeast

In the Northeast, temperatures were near to above average midweek, but they will cool by the weekend, with snow in the forecast for the interior.

Albany was forecast to reach 70 degrees for a high temperature Wednesday afternoon, but then plummet to the mid-30s by Friday morning, with a winter storm watch in effect outside of the city.

This is a similar story across much of the Northeast, with the warmer-than-normal temperatures through Wednesday before a cold front moves through late week. This will make for a 20-degree drop in temperatures between Wednesday and Thursday in New York and New England.

The high temperatures will be 10-20 degrees below normal for this time of the year. The Mid-Atlantic should cool down slightly as well, with highs more like 5 degrees below normal, into the 50s and 60s.

With this cold, there is also the chance for snow. A weak area of low pressure located over the central US will track offshore and up the Northeast coast Thursday through Saturday, introducing the risk for snow in the higher elevations of New England and New York state.

snow and rain accumulation northeast 041421

The heaviest of the snow will be Thursday night into Friday across inland locations. There is the chance temperatures do get cold enough for some snow in some coastal locations of New England, but most of the coast will deal with a cool rain.

Much of the Northeast could use the precipitation, with parts of the region at less than 50% of normal precipitation the past 90 days.

In the higher elevations of New England, snowfall could add up to 8 to 12 inches, with lower totals at the mountains’ bases.

In a typical season, Albany’s last measurable snowfall is on April 6, but the record latest is May 18. If snow does accumulate later this week, then the city will have a later-than-normal end to its snow season. Last year, it snowed until April 22, with a storm total of 0.1 inches.

A warmup will likely return, with temperatures slightly above average beginning this weekend. Highs will be back in the 60s for many in the Northeast.

Even colder in the middle of the country

The most significant cold compared to normal this week will be across the central US, where there is the risk for snow.

Widespread high temperatures of 15-25 degrees below average are forecast across the Plains. This could last through at least this upcoming weekend as the colder air moves south.

Since it is spring, this will not be an Arctic outbreak of extreme cold like what Texas experienced in February. Still, some cities could break their daily coldest high temperature records. This includes Austin, Texas – a forecast high of only 65 degrees on Saturday could break the record coldest 66 degrees set in 1947.

Highs will range from the 30s and 40s in the Northern Plains and lower elevations of the central Rocky Mountains this week. In the Southern Plains, temperatures won’t cool down until this weekend. Highs could drop as much as 20-30 degrees between mid-week and the weekend in Texas.

The Southeast will also cool down, with the coldest air compared to normal between Thursday and Saturday. Widespread high temperatures in the 60s and 70s are forecast during this time period.

Friday high temps 041421

This spell of cold temperatures in the Central Plains will mix with precipitation from a low-pressure system forming near the Rocky Mountains late week. Therefore, snow will be possible across much of Colorado, Wyoming and western Nebraska and Kansas.

Widespread snow and wintry mix are forecast, with snowfall of 1 to 5 inches expected in the lower elevations of this part of the US between Wednesday night and Friday night.

In this part of the country, snow is not too unusual this time of the year. North Platte, Nebraska, for example, typically experiences the last measurable snowfall on April 15. In Denver, the last day is usually on April 28, but the city has received snowfall five out of the past 10 years in May.

Next week should remain cool across much of the central US, according to the Climate Prediction Center.

CPC outlook 041421

The center is forecasting a cooler than average East and warmer than average West, except for New England for early week and South Florida staying on the warm side.

Quieter severe weather pattern

The current overall weather pattern is having an impact on severe weather.

A classic setup for severe weather includes a dip in the jet stream across the West, which often triggers low pressure to form in the Plains. This low steers warm temperatures and high humidity into the South. In some cases, the ingredients line up to produce intense thunderstorms and tornadoes.

The weather pattern currently dominating the US is quite the opposite.

There is still the risk for some isolated severe thunderstorms near the Gulf Coast, which is forecast Wednesday and Thursday, according to the Storm Prediction Center, but the threat is not very widespread and nothing like a tornado outbreak.

There were strong storms in southern Louisiana on Tuesday that brought extreme wind, hail and rough seas to the region.

So far this year, the US has 252 reported tornadoes, which is below the year-to-date average of 312. The last time we have had this few by this time of year was 222 tornadoes in 2018, so this mid-April pattern will likely set the US back even more in terms of the number of tornadoes.