A slow-moving front draped across the south-central portion of the CONUS continues to focus much of the active weather over the CONUS, and will continue to do for the next several days.
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Since this morning, scattered showers and thunderstorms have expanded from the Tennessee Valley into portions of the Northeast and New England as an influx of moisture races toward the Eastern Seaboard.
Moderate to locally heavy rainfall is possible with this activity, although no excessive rainfall is anticipated today.
In the meantime, a jet stream arriving from the Eastern Pacific will begin to interact with a moisture laden portion of the front across the Southern Plains.
This interaction will yield a more robust round of heavy rain from the Southern Plains eastward across the Lower Mississippi Valley, and into the Tennessee Valley Wednesday through Thursday morning.
In all, the latest WPC forecast calls for rainfall totals upwards of 2 inches over portions of the Ozarks through Thursday.
This rainfall may lead to isolated instances of flash flooding over portions of Eastern Oklahoma, Missouri, and Arkansas through Thursday morning, where a Slight Risk (level 2/4) of Excessive Rainfall is in effect.
In addition, temperatures will be cold enough to support wintry precipitation across portions of the Central Plains.
The overall pattern supporting the wet weather from the southern Plains into the Northeast will also support much above average temperatures over the next few days over the Central to Southern Plains, and eastward into the East Coast.
After a few record high minimum and maximum temperatures were set yesterday over the Southern Plains, a much more expansive area of potentially record high minimum (and a few daily maximum) temperatures are forecast Wednesday and Thursday across portions of the southern Plains, Lower Mississippi Valley, Tennessee Valley, Mid-Atlantic and Northeast.
Below average temperatures over the next few days are expected west of the Rockies and across the Northern Plains.
The greatest below average temperatures are expected across the Northern Plains where Arctic air will keep temperatures 15-20 degrees below average from eastern Montana, across the Dakotas and into Minnesota Wednesday into Thursday.
However, record cold temperatures are not expected across this region.
This area will also see the threat of periods of accumulating snows over the next two days.
Amounts are not expected to be very heavy, generally in the 1 to 4 inch range.
The heaviest snows over the next few days expected through the Rockies of Colorado, northwest Montana and northern Idaho where totals in excess of a foot are possible.
By Thursday however, another Pacific system arriving along the West Coast will spread low elevation rainfall and high elevation snows to the Pacific Northwest into Central California.
The current WPC Winter Storm Severity index currently indicates minor (level 1/5) to locally moderate (level 2/5) impacts are possible from this wintry weather over the Olympics and Cascades Thursday. ■