All Weather News

Snow, Bitter Cold, With More to Come!

22 Dec 2008, 9:59 am
WRF/NAM 2 Meter Temperature Animation
WRF/NAM 2 Meter Temperature Animation
Today's Outlook
Today's Outlook
Christmas Eve Mess
Christmas Eve Mess
Denise LaPorte's Dog Riley Gives His Thoughts on Winter
Denise LaPorte's Dog Riley Gives His Thoughts on Winter - Chicago Tribune

Christmas Lights Under The Snow Credit: Digmunster - KOMONEWS
Christmas Lights Under The Snow Credit: Digmunster - KOMONEWS
Travel was interrupted throughout many regions of the nation over the weekend from the Pacific Northwest to America’s Heartland as planes, trains, and automobiles were dealt heavy blows of snow and bitter cold, that will unfortunately continue for a bit longer.

To give an overview of temperatures through the first part of Christmas morning, we have our WRF/NAM 2 Meter Surface Temperature Animation that can be viewed full size by either clicking here, or the graphic at top left (feel free to link to, or use the image on your site as long as it remains unaltered).

The animation represents this morning’s 06z run, and at initialization clearly depicts the massive jolt of arctic air trapped in the nation’s midsection this morning. I can attest to this fact, as this morning as I went out for my morning latte and bagel, the outdoor temperature sensor on my Lincoln said “2°F,” and it definitely did not want to start. It was the scenario where the car barely turns over once, and you ask yourself: “Is a latte really worth this?” Then of course, you keep the key turned and eventually the car turns over if you’re lucky. Fortunately for me it did, and after my latte my typing speed has increased by about 40wpm =)

Watch the animation closely as the 0°F temperatures and below (purple colors) slowly stream out of the Midwest to be replaced by above freezing (note the small red TOI {temperature of interest} line that indicates the freezing mark 32°F) temperatures. Fortunately the subzero temperatures will mostly exit the country to be replaced by something a little more bearable, other than the highest elevations of the Rockies and the extreme northern Tier.

The reason warmer air will advect into the midwest is a surface low that will slowly build and move in the general direction of the Great Lakes. As usual the exact path is somewhat difficult to discern, but at this point models tend to agree that the center of the low will pass close to Chicago Proper.

When this type of setup occurs at this time of year, it brings a mixture of precipitation types, with snow on the northern edge, mixed freezing rain / sleet in the middle of a dividing line with liquid precipitation on the southern edge. In the graphic at left I have generalized the areas of projected precipitation associated with the surface low as a strong influx of gulf moisture will stream into the midwest. One key with this setup will be the marriage of surface temperatures with those aloft, as it is likely that a wide area of freezing rain and sleet will occur, however if temperatures should continue to rise as the low pushes further north, freezing rain and sleet should migrate over to all liquid precipitation.

The Pacific Northwest will continue to be bombarded through Wednesday as a nice split flow setup invades the region. Today areas all across the Rockies an upper trough will continue to lower heights as moisture rides the Pacific Train into the region spurring very heavy orographic snow along all of the mountainous terrain from the central Rockies through the Pacific Northwest, where as usual the Cascades will receive at least a foot of snow, along with the Sierras and San Juan Mountains and Colorado Rockies.

The Key for the Pacific Northwest is what is to come… again =) Most of tomorrow will be fairly quiet, however a nice split flow regime will invade on Tuesday evening through Wednesday, where snows will begin across northern California and into the Sierras, but by Wednesday the split flow will give way to an intensified trough allowing for an absurd amount of Pacific moisture to invade the region with once again well over a foot of snow for the Cascades, and a chance of snow for Seattle.

Please be sure to view our Advisory and Radar Centers for the latest updates and developments.

As always stay tuned to your favorite weather outlet, stay informed, and stay safe!



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