An active and anomalous weather pattern will continue to impact the Nation over the next few days, with several potential hazards spanning from severe weather to potentially dangerous heat.
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Starting in the north-central U.S., a surface boundary currently lifting north as a warm front this afternoon and is likely to spawn numerous thunderstorms capable of producing damaging wind gusts, large hail, and tornadoes from eastern South Dakota and northwest Iowa toward southern/central Minnesota and northwest Wisconsin.
These thunderstorms will also have the potential to contain heavy rainfall rates and lead to instances of flash flooding.
An area of low pressure is forecast to develop along this quasi-stationary boundary on Thursday over the central High Plains and ahead of an approaching upper-level trough ejecting out of the Intermountain West.
While rapidly strengthening, the area of low pressure is forecast to move northward into the Northern Plains and spread areas of showers and thunderstorms.
Once again, the potential for severe thunderstorms will exist from the northern/central Plains towards the Upper Midwest as a strong cold front swings eastward.
The Storm Prediction Center has issued an Enhanced Risk (level 3/5) of severe weather on Thursday across parts of Minnesota, southeast North Dakota, eastern South Dakota, northwest Iowa, and eastern Nebraska.
Additionally, heavy rain over already saturated soils is possible across eastern Montana, North Dakota, and northern Minnesota on Thursday.
As a result, instances of flash flooding are possible which has prompted a Slight Risk (level 2/4) of excessive rainfall to be issued for this region.
By Friday, the main low pressure center is expected to enter south-central Canada as the attached cold front pushes into the Midwest and southern Plains.
The severe weather threat on Friday is forecast to diminish slightly and extend along the cold front.
Ahead of the approaching western U.S. upper-level trough, an anomalous ridge set up over the Great Lakes and northern New England will lead to widespread above average temperatures.
Highs 20+ degrees above average are forecast on Thursday and Friday across the Great Lakes, Interior Northeast, and northern New England, which equates to temperatures into the 80s.
Highs into the 90s will reach as far north as Iowa on Thursday, which combined with heat indices approaching 100 degrees, has prompted Heat Advisories to be issued across parts of the Midwest.
Meanwhile, much of the southern Plains will continue to experience summer-like warmth and highs into the mid-to-upper 90s.
Dozens of daily high temperature records will potentially fall on Thursday throughout 16 states spanning from Texas to Maine.
The anomalous early-season heat is anticipated to relax slightly on Friday (outside of northern New England) as the cold front and associated thunderstorm activity enters further into the Midwest and central/southern Plains.
As the previously mentioned storm system strengthens over the central High Plains, gusty winds and low relative humidity will make for dangerous fire weather conditions over the Southwest.
The Critical Fire Weather risk also extends into the southern Rockies this evening and central/southern High Plains on Thursday.
Red Flag Warnings and High Wind Warnings have also been issued.
Elsewhere, a retrograding low pressure system and associated moisture from the western Atlantic is forecast to begin entering the Southeast by late Thursday.
Areas of showers and isolated thunderstorms will lead to unsettled weather along the East Coast from southern New England to northeast Florida.
Rain is also expected to enter the Northwest as a frontal system swings into the region on Thursday, with locally heavy rainfall possible along coastal regions of Washington and Oregon.
Snow is likely in the higher elevations of the Cascades before spreading into the northern Rockies Friday morning. ■