Published: June 11,2017
The central and eastern U.S. will start this week with a taste of summer, but it will feel more like winter in parts of the West.
This pattern will not last long. By late week or next weekend, the Midwest and Northeast will begin to see temperatures moderate, and a warm-up is in store for the West.
In addition to the temperature changes, severe thunderstorms may impact portions of the Plains and upper Midwest this week, and wet and stormy conditions will prevail across parts of the South.
1) Heat Wave in Midwest, NortheastAn upper-level ridge of high pressure, or northward bulge of the jet stream, will build across the central and eastern U.S. early this week. This will allow a more southerly flow to develop, bringing hot and humid conditions into much of the Midwest and Northeast.
Daily record-high temperatures are also expected in the East early this week.
(MORE: Heat Wave to Spread Record Highs)
The result will be several days of temperatures in the 90s and dew points in the 60s, making it feel humid and even hotter than the reading on the thermometer. Highs will be 10 to 25 degrees warmer than average into midweek in the Midwest and Northeast. The most persistent heat will be in the Midwest.
Low temperatures will also be above average, with lows only dipping into the 70s for many locations.
(MAPS: 10-Day Forecast)
Another cold front will push into the Plains midweek, also allowing temperatures to moderate. This cold front will slowly push eastward late week and will bring cooler conditions to the Midwest by next weekend.
2) Severe Thunderstorms May DevelopA stationary front brought severe thunderstorms on Sunday from South Dakota and Nebraska northeastward into northern Michigan.
Monday and Tuesday, a strong area of low pressure is expected to move into the Plains. Ahead of this system, the warm temperatures and humid conditions will be in place.
Strong winds in the upper levels of the atmosphere, combined with ample moisture and the eastward tracking cold front, will result in enough instability to likely produce severe thunderstorms.
(MORE: Severe Thunderstorms Threaten Plains, Upper Midwest into Midweek)
Severe Thunderstorm Setup
Damaging wind gusts, large hail and a few tornadoes are concerns early this week with any severe thunderstorms that fire up.
(MORE: Tornado Central)
A few strong to severe thunderstorms are also possible mid-to-late week as this system pushes eastward, but the details are uncertain at this time.
3) Heating Up Again in Parts of the WestThe week will begin with a strong upper-level trough, or southward dip in the jet stream, over the Northwest. The result will be rain and higher-elevation snow, along with chilly conditions for mid-June.
(MORE: June Snow Early This Week)
High temperatures will be 10 to 25 degrees colder than average early this week across the West. Highs will only top out in the 50s and 60s for much of the Pacific Northwest and Great Basin, with 70s and 80s from Southern California into Las Vegas.
This Week's Forecast
The result will be a return to drier conditions throughout the West, with the possible exception of western Washington and northwestern Oregon.
(MAPS: Weekly Planner)
In addition, temperatures will rise through mid-to-late week. Above-average temperatures are expected from California into the Great Basin and Southwest by Friday, and this increase in temperature is expected to prevail into next weekend.
Highs will soar into the triple digits for the Desert Southwest, with 80s in much of the interior West. This pattern may result in a significant heat wave in parts of California and the Southwest.
4) Wet, Stormy Week in the SouthHigh pressure brought mainly dry conditions across the South through the weekend, with the exception of Florida and the northern Gulf Coast which saw a few scattered showers and thunderstorms.
This area of high pressure will begin to weaken early this week as it slides eastward. A southerly flow will prevail across the region and tropical moisture will increase, resulting in a return to wet weather.
By midweek, a cold front will push into the southern Plains, bringing a few thunderstorms there, as well. This boundary may stall and could bring repeated rounds of rain to portions of the region.
The risk of showers and storms will also persist into late week for much of the South in areas east of the Mississippi River.
(MORE: Why Pop-Up Summer Thunderstorms are Hard to Predict)
There will be plenty of moisture in the region, which may enhance rainfall and bring the risk of flash flooding. The good news is that, although a wet pattern is expected, we are not anticipating the heavy rainfall that occurred in Florida last week.
The cloud cover and thunderstorms will help to keep temperatures near to slightly below average across the region through this week.
MORE: Florida Storms and Flooding, Early June 2017 (PHOTOS)
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