Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 254 PM EST Fri Nov 08 2024 Valid 00Z Sat Nov 09 2024 - 00Z Mon Nov 11 2024 ...Historic winter storm to bring more heavy snow and blizzard conditions to portions of Colorado, New Mexico, and the Oklahoma and Texas Panhandle through tonight... ...Showers and thunderstorms will bring the threat of flash flooding to the southern Plains through tonight, and into the Lower Mississippi Valley and Mid-South for Saturday and Saturday night... ...Above average temperatures continue for much of the country this weekend... ...Atmospheric river to arrive across the Pacific Northwest on Sunday with heavy coastal rains and high elevation snowfall... A historic winter storm with very heavy snowfall will continue to impact the southern Rockies and portions of the immediate southern High Plains going through tonight, including areas of Colorado, New Mexico and small parts of the Oklahoma and Texas Panhandle region. Going through tonight, areas of eastern Colorado will see the heaviest additional snowfall totals with locally over a foot of new snow expected. This will be supported by snowfall rates that will occasionally fall at 1 to 2 inches/hour. Strong and gusty winds accompanying the snow will also continue to promote blizzard conditions and especially over northeast New Mexico where Blizzard Warnings remain in effect. As a result, travel will continue to be very difficult to impossible, and especially with numerous road closures already locally in place. The very slow-moving area of low pressure responsible for this historic, multi-day winter storm will begin to advance northeast out across the central Plains this weekend, and this will allow for the snow to begin tapering off on Saturday. Meanwhile to the east, on the warm side of the system, the influx of Gulf of Mexico moisture and increased instability will to lead to widespread showers and thunderstorms producing very heavy rain over the next couple of days. This will cover much of the southern Plains region going through tonight along and ahead of an eastward moving cold front. A Slight Risk of excessive rainfall (level 2/4) covers much of Oklahoma down through northern and central Texas where areas of heavy rain over locally saturated ground may lead to scattered instances of flash flooding. As the storm system ejects farther out over the Plains, the excessive rainfall threat will shift off to the east and move into the Lower Mississippi Valley and Mid-South going through Saturday and Saturday night. The same cold front will focus a north to south axis of heavy showers and thunderstorms across this region, and with some areas still moist from heavy rains earlier in the week, the additional rainfall may result in scattered instances of flash flooding. As a result, a Slight Risk of excessive rainfall (level 2/4) covers this region as well. Some of these rains are forecast to linger into Sunday as the cold front continues to press eastward, but areas farther east across the Tennessee Valley that see moderate to heavy rain will greatly benefit from these rains given the extremely dry weather that has been in place over the last month. Temperature-wise, most of the country will continue to see above average temperatures going into the weekend. Many areas of the northern Plains and Midwest south down through the Mid-South and Gulf Coast states will still be seeing high temperatures on Saturday and Sunday that will be 10 to 15 degrees above normal for this time of the year. This will include high temperatures well into the 70s and 80s across the South where there may be a few record high temperatures recorded. Mild conditions will be in place along the East Coast, with some exception to the interior of the Mid-Atlantic and the southern Appalachians where the arrival of clouds and rain by Sunday will keep temperatures cooler and closer to normal. The aforementioned southern Rockies and High Plains area where the ongoing winter storm is focused should see high temperatures as much as 10 to 20 degrees below average on Saturday, with some moderation expected on Sunday. By Sunday, a new storm system is forecast to impact the Pacific Northwest and this will bring atmospheric river conditions to the region. This influx of Pacific moisture will bring heavy rains to the coastal ranges of Washington and Oregon, and some higher elevation snowfall for the Cascades. The heaviest rains should be focused over the Olympic Peninsula where a few inches of rain will be possible. Orrison Graphics available at https://www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php