NWS Short Range Nationwide Forecast Discussion Valid 12Z Tue Oct 17 2023 - 12Z Thu Oct 19 2023

Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 400 AM EDT Tue Oct 17 2023

Valid 12Z Tue Oct 17 2023 - 12Z Thu Oct 19 2023

An Alberta clipper will bring very gusty winds and a round of rain across the northern Plains later today and Wednesday, spreading into the Great Lakes Wednesday night and early Thursday...

A warming trend is in store for the eastern half of the country as an expansive cool airmass moderates...

Warm and dry air across much of the western U.S. will spread into the Plains but rainy conditions remain over the Pacific Northwest...

The weather pattern that has been sustaining an expansive area of cool air mass across the eastern half of the country the past few days is forecast to slowly break down during the next couple of days as an Alberta clipper tracks into the northern Plains.  Below normal temperatures that have been felt across the central to eastern U.S. will gradually moderate as a high pressure ridge slides eastward to reach the East Coast later on Wednesday, allowing a reservoir of warm air over much of the western U.S. to reach into the Great Plains.  The warming process will be the slowest across the South where the associated cold upper trough will be the last to break down.  Scattered showers will once again be found from interior New England to the lower Great Lakes and down across the Ohio Valley this morning with plenty of cloudiness.  A slow clearing and warming trend is expected through the next couple of days as this cool weather pattern breaks down further.

While much of the interior western U.S. has been dry, moisture associated with a cold front ahead of an upper trough will bring windy and rainy conditions across the Pacific Northwest and down into northwestern California today.  This latest round of rain is forecast to end later today from Oregon southward.  Farther north though, rainy weather is expected to continue across the Olympic Peninsula for at least a couple more days with the arrival of a warm front from the next Pacific system.  Meanwhile, a piece of the lead upper trough is penetrating farther inland, with a round of rain and high-elevation wet snow moving across Idaho and Montana this morning.  By tonight into early Wednesday, an Alberta clipper is forecast to slide southeastward into the far northern Plains where a round of mostly light rain can be expected.  Strong winds including maximum gusts up to 60 mph are possible later today across parts of the northern High Plains.  This has prompted High Wind Warnings to be issued for parts of northern and central Montana.  On Wednesday, the clipper is forecast to head east toward the upper Midwest, spreading rain into the Great Lakes and down into the mid-Mississippi Valley by Wednesday night and early Thursday.  Meanwhile, southerly flow developing ahead of the Alberta clipper and a lee trough near the foothills of the Rockies will allow warm air to start filtering into the High Plains today, resulting in afternoon high temperatures well into the 80s in the afternoon as dry conditions continue.  Meanwhile, above normal temperatures will continue over the Desert Southwest where high temperatures could top the century mark for the next few days.