A significant winter storm will impact much of the West heading into the weekend, including dangerous, blizzard conditions for the Sierra Nevada.
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An upper-level trough over the northeastern Pacific digging slowly southward and inland over the West Coast will allow for a multi-day influx of moisture from the Pacific/Atmospheric River as colder air spreads southward.
This will bring heavy snowfall to many of the higher elevation mountain ranges across the Pacific Northwest, northern/central California, the northern/central Rockies, and Great Basin, following a general southward trend each day Friday and Saturday.
Snow totals locally as much as 12"+ are forecast through Sunday morning.
In addition, widespread damaging wind gusts of 55+ mph are forecast across much of the region, with even stronger gusts of 75+ mph for higher elevations, leading to the risk of downed trees and power lines.
The most intense combination of snow and wind will come together over the Sierra Nevada, where a powerful blizzard is expected.
Extreme snowfall totals of 5-12 feet (locally even higher) are forecast through the weekend, with high snow rates and winds leading to blowing/drifting snow and whiteout conditions, making travel impossible.
For lower elevations, the system will bring moderate to heavy rainfall to coastal locations, with a mix of light to moderate rain/snow for interior locations, though any accumulations should remain limited.
Some light snow may spread into portions of the northern High Plains Saturday as the system continues east.
The weather system will also usher in cooler, below average temperatures, with highs generally in the 30s and 40s for the Pacific Northwest, northern California, northern Rockies, and Great Basin, with 50s in central California and 60s into southern California.
To the East, lift ahead of a shortwave moving eastward from the Mississippi Valley towards the East Coast as well as Gulf moisture flowing northward over a quasi-stationary boundary draped along the Gulf Coast will bring widespread showers and thunderstorms across much of the Southeast Friday.
Some locally heavy downpours are possible, especially in vicinity of the boundary along the central Gulf Coast and along the Carolina coast.
The boundary is forecast to lift northward along the East Coast as the upper-level shortwave approaches, spreading rain chances into the Mid-Atlantic overnight Friday and New England during the day Saturday, with some locally heavy showers most likely once again for coastal locations in vicinity of the boundary.
Showers and storms will also linger across portions of the coastal Southeast into north Florida and the Florida Panhandle.
Much above average, Spring-like high temperatures are once again expected across much of the Plains and Midwest heading into the Weekend.
The greatest anomalies are forecast for the northern Plains Friday and the central Plains into the Upper Mississippi Valley Saturday where highs will be upwards of 25-35 degrees above normal, reaching into the 60s and 70s.
Elsewhere, highs will be in the 40s and 50s in the Great Lakes.
Highs Saturday will warm into the 60s and 70s for the Middle/Lower Mississippi Valley, with 80s returning to Texas.
The warm temperatures as well as dry conditions and some gustier winds along the central/southern High Plains will bring the risk for wildfires this weekend, with the Storm Prediction Center introducing a Critical Fire Weather outlook (level 2/3) for Saturday.
After a chilly day Friday in the Southeast, with highs generally in the 40s and 50s, temperatures will quickly warm back up to average to slightly above average levels Saturday, with highs in the 60s and low 70s.
Temperatures will also rebound for much of New England, warming from the 20s and 30s Friday into the 40s Saturday.
Conditions will remain near to above average in the Mid-Atlantic, with 40s and 50s expected. ■
A hyperactive weather pattern will bring an expansive low pressure system across mainland U.S., resulting in widespread impactful weather to progress from west to east across the country through the next few days.