Four Things We Are Watching This Week: Wintry North, Warm West, Storms Return, Wet Pacific Northwest

Lightning Fact or Myth?

April can be a month of lots of weather changes and depending on where you live, the first full week of April may not feel like spring, but more like winter or even summer.

This week will feature a low pressure system that will bring cold temperatures and some snow to portions of the Upper Midwest and Northeast. This same system will also bring another round of rain, with a few thunderstorms, from the Plains to the Southeast. Meanwhile, wet weather will start the week in the Pacific Northwest but most of the West will enjoy above-average temperatures.

Below we go into more detail on each area that we are watching this week.

1) More Like Winter

After a warm March for much of the Midwest and Northeast, April is starting off quite the opposite. Below-average temperatures were first experienced this weekend and will continue for much of the week ahead. 

(MORE: April to Begin With Cold Temperatures)

High temperatures will be up to 25 degrees below average at times and low temperatures will also be colder than average, especially midweek in the Northeast when a few daily record low temperatures are possible.

Highs will top out in the 30s and 40s for much of the Midwest and Northeast this week, with a few 20s near the Canadian border. At times during the week, temperatures may reach the 50s in parts of the Ohio Valley and toward the East Coast. 

Morning low temperatures will be quite chilly through midweek, with many locations seeing lows in the teens and 20s. Temperatures may dip into the single digits from the Upper Peninsula of Michigan into the interior Northeast.

(FORECAST: Chicago | Detroit | Burlington, Vermont | New York)

In addition to the chilly temperatures, snow is also possible. Winter Storm Ursula will bring snow into the Great Lakes and portions of the Northeast through Monday.

The next low pressure system will bring the chance for snow or a mix of rain and snow from the northern Plains into the Upper Midwest and Great Lakes Tuesday into Wednesday. The chance for wintry precipitation will then push east from the Great Lakes into northern Pennsylvania, Upstate New York and portions of the interior Northeast and New England during the second half of the week.

As this system moves off the East Coast, the cold front may linger and another area of low pressure could develop off the Northeast coast or inland from the coast. This could enhance snowfall and rainfall, as well as bring an increase in wind, to the region late week. 

2) Warm West

It may feel more like late spring or early summer for many in the West this upcoming week, due to a ridge of high pressure. Strong high pressure is expected to build along the West coast early in the week and then slide eastward, allowing an offshore flow to develop which will result in very warm temperatures, including along the coast.

High temperatures will be up to 30 degrees warmer than you would normally expect for early April. High temperatures will climb into the 70s and 80s for much of the region by midweek, with 50s and 60s in the higher elevations. In southern Arizona and southeastern California temperatures will reach the 90s, with Phoenix topping out in the mid 90s.

(MORE: April Temperature Outlook)

Many locations will see the warmest temperatures so far this season and a few record highs are possible as well. 

The highest temperature recorded in San Francisco this year has been 77 degrees and temperatures may soar into the lower 80s Wednesday. Las Vegas may also see the warmest conditions so far this season, as their highest temperature has been 87 degrees.

A few cities that could set new daily record highs (current record is in parenthesis): 

• Sacramento: Tuesday (85 degrees) and Wednesday (90 degrees)
• Medford, Oregon: Wednesday (83 degrees) and Thursday (83 degrees)
• Portland, Oregon: Wednesday (78 degrees), Thursday (79 degrees) and Friday (74 degrees)
• Seattle: Friday (71 degrees)
• Boise, Idaho: Thursday (79 degrees) and Friday (82 degrees)

Changes, however, are expected late in the week, as an area of low pressure moves into southern California. This will bring cooler temperatures, along with the chance of showers to the Southwest to end the week.

3) Early Week Rain

Before the warmer temperatures arrive in the Pacific Northwest, a cold front will push through the region into Monday, bringing the chance for rain.

Rain is expected to spread across Washington, Oregon and possibly far northern California into early Monday. A rumble of thunder is even possible.

Snow is also expected in the Cascades and behind the cold front snow levels will drop to around 3500 feet. A winter weather advisory has been issued for portions of the Cascades for Monday with up to 10 inches expected.

Showers may linger in western Washington and northwestern Oregon into Monday night due to onshore flow.  

(FORECAST: Seattle | Portland | Missoula, Montana)

Rain and some higher elevation snow will also extend into Idaho, Montana and Wyoming Monday into Tuesday.

Generally light rainfall amounts are expected across the region through early week, with most areas seeing less than an inch of rain.

(MAPS: Weekly Planner)

A few showers are also possible in western Washington on Tuesday, as a warm front moves through the area. Mainly dry conditions are expected Wednesday through Friday across the Pacific Northwest, as high pressure is expected to dominate the region.

4) Thunderstorms and Wet Weather Return

The low pressure system that will bring the chance for snow to portions of the Upper Midwest and Northeast, will also bring the chance for showers and thunderstorms farther south. The good news is severe thunderstorms are not a major threat, though there may be a few.

Rain and thunderstorms will begin to develop late Tuesday in portions of the Midwest, mid-Mississippi Valley and possibly the central Plains. An isolated severe thunderstorm is possible in northeastern Kansas, northwestern Missouri, southeastern Nebraksa and southwestern Iowa.

(FORECAST: Tulsa | Indianapolis | Atlanta)

On Wednesday, the chance for rain and thunderstorms slides east stretching from the Ohio Valley into portions of the South. An isolated severe thunderstorm is also possible from southern Illinois, western Kentucky and southeastern Missouri into southeastern Arkansas and northwestern Mississippi. 

(MORE: More Than a Dozen Tornadoes Hit the South)

The chance for showers and thunderstorms will reach the Southeast and Mid-Atlantic Wednesday night and continue into Thursday. This system will then push off the East Coast by Friday.

Widespread heavy rainfall is not expected with this system, but heavy rain is possible in any thunderstorms that develop.

Check back with weather.com for the latest forecast and updates.

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