Now that we’re less than 7 days from Christmas, our Southern Snow app will provide you a super-localized forecast on the upcoming snow potential this Christmas week. Our written forecast discussions, such as this one, should provide a nice ‘heads up’ that may or may not be currently reflected in the daily forecasts. You sort of get the best of both worlds if you have the app.
A strong shortwave will enter the Pacific Northwest on Tuesday and sweep across the Rockies on Tuesday and Wednesday. This system will add to existing snow cover across the Cascades, the northern Sierra Nevada region and most of the Rockies, ensuring a White Christmas.
Snow cover from last week’s nor’easter will begin rapidly melting on Christmas Eve and Christmas Day. However, areas that picked up feet of snow across the Mid-Atlantic and Northeast will still have snow cover from the event, even at lower elevations.
The upper Midwest and the Great Lakes region will have several opportunities for snow in the coming days. A weaker system will pass through the area early this week, and a stronger storm system will set the stages for lake-effect snow on the backend on Christmas Eve and Day.
The same mid-week system has the potential to bring noteworthy snow accumulations to areas along and west of the Appalachians, along with western areas of New York.
One could make the argument that some areas included in the possible probabilities category should eventually get bumped up to moderate chances. I concur. As one shortwave swings across the Midwest and Great Lakes mid-week, another wave will dig southeastward into the Plains and mid/lower Mississippi Valley. As a result, a second surface low could develop farther south early Christmas Day, bringing snow chances as far south as eastern Tennessee and the northern Gulf coast states.
The air mass behind the advancing strong cold front will be very dry, so there remains much uncertainty on moisture availability. Nonetheless, snow-to-rain ratios will be high behind the front, so even a little moisture and lift would do the trick. Climatologically, these setups have a relatively high probability of being a bust for snow, especially farther south. However, if I see that short-range guidance supports higher totals, I’ll probably need to bump up probabilities to a moderate for some.
Before coming eastward, the same wave will have the potential to produce accumulations east of the Rockies across Colorado, Wyoming, and into parts of the Northern/Central Plains before Christmas Day. It’s quite likely some of those areas will get pushed into moderate probabilities in a subsequent update by Firsthand Weather.
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We made a post the other day asking our followers when they had experienced their last White Christmas. Quite a few said never. A few others said back in 2010. Since many of our readers live in the Southeast, those responses weren’t all that surprising. Climatologically, having snow on the ground at some point on Christmas Day in the Southeast is exceptionally rare. Though, not impossible. . .
In the coming days, we’re going to discuss those years that the Southeast had a White Christmas. They may be few and far between, but there’s value in revisiting the conditions and overall pattern that brought those rare snowy Christmases.
In this article, we will take a peek at how the pattern will likely evolve from now through Christmas Day. The overall pattern will remain quite progressive. Meaning, most regions of the U.S. will not remain under the influence of troughing or ridging for more than a few days at a time, if that. Unfortunately, such a setup favors lots of swings in temperatures.
For the first time in a while, temperatures MAY actually feel like Christmas on Christmas Day in the Southeast (give or take a day). Most model guidance agrees that a longwave trough will develop across the eastern half of the U.S., as ridging amplifies across western Canada and eastern Alaska. This pattern configuration favors anomalous warmth along the West Coast and into the Southwest. An anomalously cold air mass will sweep across most locations along and east of the Rockies. Even Florida could get in on this chilly air mass!
Most reading this post are already wondering, will there be any precipitation to go along with that brief shot of cold air in the Southeast? Maybe. The models indicate that a shortwave could become detached from the main flow and close off into a mid-level low as it approaches southern California and Baja California sometime next week. It would eventually get swept eastward by the southern stream. But features like these can meander for a while or even retrograde westward before getting reabsorbed back into the main flow. If the cold air intrusion is a strong as modeled, there could be about a two-day window, probably a day or two after Christmas, that any passing southern stream system could produce wintry weather for parts of the Southeast.
Taking a look at projected 500mb geopotential height anomalies from the latest European model, it already has the longwave trough lifting northeastward by the 26th. At the same time, the closed low quickly moves eastward across Texas/northern Mexico. Residual cold air may hang around for a day or two tops, thanks to a departing surface high. This closed low, or any southern stream feature for that matter, would need to encroach upon the Mid-South and Southeast just as the long-wave trough begins lifting out.
If I were a betting man, I wouldn’t put anything down on a White Christmas happening across the Southeast at this time. Yes, there could be a very brief window for some action right after Christmas Day, but that window appears to be short. I’d certainly recommend not getting too hung up on model guidance in the coming days. Large inconsistencies may exist in how models handle any closed low that develops. But hey, a small chance is always something to watch!
Make sure you download our new mobile app that’s dedicated to providing you with detailed snow forecasts. Firsthand Weather recently launched a new mobile app called Southern Snow for iOS devices, which gives you a snow forecast for anywhere in the U.S! If snow starts showing up in the forecast, Southern Snow will let you know.
Have you ever wanted a mobile app solely dedicated to providing you with detailed snow forecasts? Well, your wish has been granted! Firsthand Weather recently launched a new mobile app called Southern Snow for iOS devices, which gives you a snow forecast at your fingertips!
Detailed weekly forecasts, including expected highs and lows
Winter weather alerts from the National Weather Service
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Snow forecasts for nearby ski resorts
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Seasonal forecasts, including our winter forecast
To celebrate the release of our new app, we’re releasing a White Christmas forecast for the entire U.S. on Saturday, December 19, 2020 at 2pm ET. When you download Southern Snow, you’ll get an alert as soon as the forecast drops!
This week’s storm system of interest has now moved away from the West Coast and begun to dig into the Four Corners region. The vigorous shortwave will continue amplifying across the Southern Plains on Tuesday. By Wednesday, it’ll begin lifting east northeastward across the Mid-South, Mississippi Valley, and Tennessee Valley. Later Wednesday, the wave will push into the Ohio Valley, the Mid-Atlantic, and New England, bringing a powerful winter storm along the East Coast from Wednesday into Thursday.
After dropping snow across the Rockies, precipitation will develop along and ahead of the shortwave across the central and southern Plains on Tuesday. The wave will trigger the development of a surface low along the Gulf coast on Wednesday, as a large swath of precipitation overspreads the Southeast, Tennessee Valley, Ohio Valley, and Mid-Atlantic. Precipitation will then begin to overspread southeastern New England by Wednesday evening, continuing into Thursday. Rain and possible storm development in the warm sector of the system will aid in the amplification of a downstream ridge. The strength of this ridge will determine how closely the surface low rides along the Mid-Atlantic and southeastern New England coast after departing North Carolina and Virginia.
Forecast Model Discussion
The operational, along with many of its ensemble members, have continued to show a more southern track of the surface low, primarily due to a weaker downstream ridge. In such a scenario, the axis of heaviest snowfall rates and accumulations would occur from around D.C. (and northern Virginia) to Philly to Long Island to Cape Cod. Areas just northwest of this line would still get noteworthy but lower amounts. The GFS-parallel, a version of the GFS still in its testing phase, has consistently been the northern outlier. This solution would largely be a miss for D.C., Philly, New York City, Long Island, and Cape Cod, but copious amounts of snow would fall northwest of this line, including over Boston.
The European model, along with the shorter-range 12km NAM, has the surface low trekking quite close to the Mid-Atlantic after moving just offshore. Both models keep the low far enough off the southeastern New England coast for the heaviest snow accumulations to still fall over Philly, NYC, Long Island, and Cape Cod.
Most model guidance indicates that downstream ridging mid-week will be flattened by the current storm system exiting New England today. However, this ridge should be more amplified than what models suggest. For that reason, I gave the GFS-parallel and the shorter-range RGEM model (not discussed above) more weight in the snow accumulation forecast below. If there’s not a northward shift in most model guidance by tomorrow afternoon, I’ll adjust my forecast to align more closely with the operational GFS, European, and other short-range guidance.
Matthew’s Snowfall Accumulation Forecast for Select Cities
Please consider downloading Firsthand Weather’s new & FREE app: SOUTHERN SNOW (Link). This app will notify you when there are winter weather alerts in your area. Also get updates on the latest snowfall accumulations from your local National Weather Service, along with detailed forecast discussions from Firsthand Weather.
A wintry blast will visit the Southern Plains this weekend, causing significant travel impacts. The storm system will dump a heavy swath of snow across parts of the Southern Plains late-Saturday into Sunday. This comes just days after a heavy snow event in northwestern Oklahoma where over one foot of snow fell. Significant accumulations are possible for Oklahoma City, Amarillo, and Tulsa.
A shortwave trough will “swing” into the Southern Plains late-Saturday. This will set the stage for precipitation development. With cold air wrapping into the system, snow is the predominant precipitation type. Initially, precipitation may fall as light rain, but wet bulbing and colder air wrapping into the system will allow a quick transition to snow across the Texas Panhandle, southern Kansas, and northern & central Oklahoma. Snow may eventually fall in southern Oklahoma and possibly the Red River Counties of northern Texas on Sunday. Snow will also sneak east into northern Arkansas on Sunday.
Widespread snow accumulations of 3-6″ are likely for the Texas Panhandle, southern Kansas, and northern & central Oklahoma. There may be “banding” of snow, which may lead to heavier accumulations. The science is too inexact to predict where these bands may setup this far in advance, but this banding could lead to areas of 8-10″ snow accumulations. Lighter snow accumulations are expected farther south for southern Oklahoma and possibly the Red River Counties of northern Texas.
Due to the heavy snow accumulations expected, winter weather alerts have been hoisted for the region. Winter Weather Advisories are in place for the Texas Panhandle, southern Kansas, and parts of central & northern Oklahoma. A Winter Storm Watch is in place for northwestern Oklahoma where a Winter Storm Warning will likely be needed. It is possible these winter weather alerts will get extended east into northeastern Oklahoma and northwestern Arkansas on Saturday.
As a nasty, cold rain falls, have you ever pondered what would’ve happen if all of that rain had been snow? As a snow-lover born and raised in the Southeast, it’s hard not to get a little frustrated when one or two minor yet significant ingredients don’t come together at the right time to bring a few inches of snow. We snow lovers usually upset those who dislike snow by talking about how much we want snow. It’s not like we can help that we like snow. When snow accumulates in the South outside of the mountains, it usually melts within a day or two anyway. Wow, I’m saying the word snow a lot, aren’t I?
Let’s talk about why a number of you will be disappointed by what happens late this weekend into early next week. A shortwave will continue pushing across the southern and central Plains today. This feature has induced the development of a surface low, now sitting on the Kansas/Missouri border. It will continue on a northeastward trajectory toward the Great Lakes region into early to mid-weekend. As a result, a cold front will push down to the Gulf coast from Texas to the Florida panhandle. This front will bring colder temperatures by mid to late weekend to most of the South, outside of areas at/near the Southeast coast and Florida.
A secondary shortwave will move into the Pacific Northwest today. Early to mid-weekend, the wave will trek southeastward across the Rockies, into the Four Corners region, and then eastward into the Southern Plains. As with the first shortwave, a surface low will develop. This feature, however, will move across the lower Plains and then across the Gulf coast states late Sunday into Monday. And, here’s the thing. This low will move into the Southeast behind the cold front. This sort of setup favors winter storms impacting parts of the Mid-South, Southeast, and Tennessee. Yet in this case, snow will fall across the Cascades, much of the Rockies, the Southern Plains, and even into parts of the Mid-Atlantic, but NOT across the Southeast and most of Tennessee.
Why Some Will Get Snow When Others Won’t
The problem is the lack of cold air. Though the cold front will have already pushed through much of the Southeast, there won’t be enough time for sufficiently cold air to spill into the region. Earlier in the week, the European model had a couple of runs that indicated a winter storm would occur, but at the time, it depicted a stronger system. In this case, the low would’ve advected sufficiently cold air as far south as Tennessee, northern Mississippi and Alabama, far northern Georgia, and central North Carolina. Given the projected surface low track, Atlanta would’ve likely missed out anyway, but places like Memphis, TN; Nashville, TN; Chattanooga, TN; Huntsville, AL; Birmingham, AL would’ve had a significant winter event. Oh well!! Instead, get ready for more rain over the weekend.
Comments on 2020-21 Winter Forecast
Throughout much of this winter, the coldest air will have a tendency to remain locked away in western/central Canada and Alaska, oftentimes only spilling into northern parts of the U.S. (check out our winter forecast for specifics). Despite this fact, much of Tennessee and the northern third of the Southeast should have a few decent chances to get wintry weather this season. However, the rest of the Southeast likely won’t fare as well. The currently active pattern across the Southeast likely won’t persist much past December, and a tendency for above average temperatures will lower those snow/ice probabilities further.
Christopher will post an article later today on potential snowfall accumulations for this Sunday and Monday across the Southern Plains and Mid-Atlantic.
Curious to know how much snow you will receive? Download Firsthand Weather’s new & FREE app: SOUTHERN SNOW (Link). This app has you covered this winter and will let you know how much snow is in your forecast and notify you of any winter weather alerts for your area!
Firsthand Weather’s duo of long-range meteorologists, Matthew Holliday and Christopher Nunley, have released 2020-2021 Winter Outlook for this upcoming season. The dynamic duo has been analyzing global phenomena’s and weather patterns, along with diving into seasonal models, to get a good handle on what old man winter will toss to the lower-48. One of the main driving influencers of this upcoming season is La Nina. La Nina is a phenomenon where the surface water over the equatorial Pacific Ocean area cooler than average. This phenomenon can have significant impacts on weather patterns across the lower-48 and around the globe, with the most noticeable impacts during the cool season (winter). The current La Nina has strengthened and is forecast to deliver similar conditions as expected during a La Nina, but there are some meaningful differences, which will be driven by the Pacific Decadal Oscillation and North Pacific Mode.
Curious to know how much snow you will receive? Download Firsthand Weather’s new & FREE app: SOUTHERN SNOW (Link). This app has you covered this winter and will let you know how much snow is in your forecast and notify you of any winter weather alerts for your area!
Take a peek at the detailed region-by-region breakdown:
Northeast and Mid-Atlantic
The winter will begin with intermittent periods of cold across the Northeast and upper Mid-Atlantic, in part driven by mid-latitude cyclones cutting northeastward toward the Great Lakes region. However, these brief periods of anomalous cold with often be followed by periods of above average temperatures. Numerous rounds of precipitation in December will keep rainfall totals around average to above average levels across most of New England. Areas across the Mid-Atlantic will begin having below-average precipitation. Snow amounts across most of the Northeast and Mid-Atlantic will not be all that impressive early on, due to an unfavorable storm track and general lack of cold air.
Moving into January and February, the coldest air will remain mostly confined to the Northern Plains, Upper Midwest, and sometimes the Great Lakes. However, cold air will spill into the Northeast often enough that temperatures should average out to around typical winter values. On the other hand, most of the Mid-Atlantic will likely experience mild conditions more often than not, with dry conditions especially prominent in January. Western parts of the Mid-Atlantic, including West Virginia and far western Pennsylvania, may be the exception to the rule in terms of precipitation. Inland New England will have the best shot at snow and/or ice. February should bring an uptick in potential winter events across inland parts of the Mid-Atlantic and the Northeast. Big swings in temperatures will likely persist across at least the lower half of the Mid-Atlantic.
We don’t expect this winter to bring quite the blowtorch warmth that characterized the last one; however, the 2020-21 winter likely won’t rival the cold 2010-11 La Nina winter or the extreme cold experienced in 2013-14 and during parts of 2014-15.
Upper Midwest and Great Lakes region
Though December will bring wild swings in temperatures, the Upper Midwest and Great Lakes region will likely experience prolonged periods of below average temperatures in January and February. Both regions will face impacts from an active southern stream storm track, which will run from the Great Plains northeastward toward the Midwest/Great Lakes. Thus, expect periods of rain and/or snow to become quite common across the area. As a result, precipitation totals through the winter should run at least slightly above average across both regions. Snowfall totals will generally run average to above average. Due to the lack of consistent cold in December, the lake-effect snow threat may persist considerably longer into the winter than one would usually expect.
Though we don’t expect this winter to bring unusually warm conditions to either region like the last winter did, keep in mind that it may take a few weeks before the brutally cold air comes to stay.
Winter will not play around for the Northern Plains. Expect brutal cold with several Arctic air intrusions. A good amount of snow is in the forecast for all of the region but the sweet spot may be for the eastern-half of the region, near the Western Great Lakes. This area has a shot to see a very active pattern with numerous opportunities for snow. At times, milder air will sneak north allowing for rain & storms, but cold air will quickly move in, changing the rain over to heavy snow. Get the snowblowers ready!
Ohio Valley and Kentucky
This region will experience an active winter right out of the gate, which will continue through most of the season. Southern stream storm systems will have a tendency to track through the Ohio Valley, often bringing rounds of rain and/or snow/ice. Temperatures will have good odds of running above average south of the Ohio River through at least January, with the coldest air likely not arriving until February. The far northern Ohio Valley may be the only ones to pull off temperatures closer to average when all is said and done. Icy weather could become a concern with some passing storm systems, and even with warmer conditions overall, it’s inevitable that sufficient cold will be available at times to bring enhanced snow chances. We expect that precipitation will run above average most of the winter.
Southeast, Tennessee, and Florida
Though not as consistently warm as the last, we expect that at least the lower half of the Southeast, much of the Carolinas, and Florida will have above average temperatures through much of the winter. Furthermore, we anticipate below average precipitation across the lower Southeast and Florida, which will increase the risk of expanding drought conditions in 2021. Despite the expected warmth and mostly dry weather, we placed much of the Carolinas in the light blue zone to emphasize icing concerns later in the winter. Severe thunderstorms could become problematic over the lower Gulf coast states at times this winter.
Farther north, the southern stream storm track could bring a slew of storm systems across much of Tennessee and potentially as far south as northern Mississippi, northern Alabama and northern Georgia in January and February. These areas could be the exception to the dry winter, where we anticipate that precipitation amounts could run average to above average. At times, sufficiently cold air could allow parts of Tennessee to get decent shots of snow/ice the latter two-thirds of winter. Northern parts of the Gulf coast states will remain a bit of a wildcard through most of the winter in terms of snow/ice chances.
The odds of snow/ice across Tennessee and northern parts of the Southeast will be higher than last winter, but elsewhere, those probabilities will be about the same.
The Mid-South will be milder & drier, overall. However, there will be quite a bit of variance at times as Mother Nature battles with warm air followed by big cold shots. While a lesser extend of old man winter’s blow is expected, there are times the northern & southern jet streams come together to produce thunderstorms, followed by a chance ice & snow near the I-20 corridor. These big temperatures swings will allow for the opportunity to see a couple notable severe thunderstorm events for parts of Arkansas, Louisiana, and Mississippi.
The Southern Plains will be a region of disparity. The northern-half of the region will experience old man winter at his finest while the southern-half of the region experiences a less-harsh version of old man winter. The northern-half of the region can expect big swings in temperatures; from mild to freezing cold. With the battle of these air masses, a few impactful winter storms can be expected with the opportunity for ice & snow. Farther south, temperatures will be a touch milder with drier conditions. This area won’t be immune to winter. Still expect to see some pesky cold air masses ooze south with a chance for one or two winter storms. Western Texas & western Oklahoma have a good shot to see these winter storms. I-20 & I-40 should see some wintry problems later in the season. With the battle between winter and milder conditions, don’t be surprised to see a couple severe thunderstorm events for Texas and Oklahoma as you approach the I-35 corridor.
Pacific & Inland Northwest and Northern Rockies
This region will experience the harshest of what winter has to offer. The Pacific Northwest will experience frequent low pressures moving ashore bringing rain & snow. These low pressures will take advantage of a stout subtropical moisture feed, at times, which will allow for heavy precipitation. Keep an eye out for flooding and landslides. The I-5 corridor will experience the wettest conditions from Portland to Seattle with shots for snow at times. The heaviest snow will fall in the Cascades & Olympics. Farther east into the Inland Northwest and Northern Rockies, the active pattern will continue with numerous shots of frigid cold air. This will lead to above average snow and below average temperatures.
Southwest and Southern Rockies
This region will be the inverse of areas farther north. The Desert Southwest can expect fairly dry conditions with below average rain & snow. This does not mean it will be warm and dry all winter. At times, pesky upper-lows will crash into California and move across the Southwest. This will bring periodic chances of rain and high elevation snow. Along with the periodic shots of precipitation, cold air will sneak into the region at times. But, overall, winter will take a vacation in this part of the county. Farther north & east into the Southern Rockies, there will be lots of battles between winter and a warmer & drier pattern. The Southern Rockies will get a fair share of significant winter storms and shots of bitterly cold air.
Wintry weather will impact parts of western Texas this weekend, which may cause a few travel issues for parts of I-10 & I-20. A potent upper-level low will move out of northern Mexico into western Texas on Saturday. This upper-level low will generate strong lift, leading to the development of precipitation. This precipitation will fall in the form of snow across western Texas due to the cold air mass in place.
Moisture is minimal with this system, which will limit the snow potential; however, enough moisture is in the atmosphere to allow for a few inches of snow. The heaviest snow will fall in the Big Bend of Texas where up to 4″ may fall. The best timing for snow will be early-Saturday morning continuing into the early-afternoon hours.
Snow may impact travel, thus, a Winter Weather Advisory is in place for this region. Parts of I-10 & I-20 will be impacted by the snow. If you have any travel plans along these Interstates, prepare for icy conditions.
A high-impact winter storm is in the process of developing across the Southern Plains. This winter storm will deliver some of the heaviest snow of the season to this part of the country.
The snow will begin Tuesday night across parts of Colorado and New Mexico, and quickly shift southeast into Kansas, Oklahoma, and the Texas Panhandle by Wednesday morning. The snow will initially be mixed with rain, but temperatures will quickly cool, allow for all snow.
The snow will shift east into parts of Missouri and Arkansas late-Wednesday into Thursday. It is possible a few flurries may mix in with the rain late in the day across northern Texas.
Some hefty accumulations are possible, thus, a Winter Storm Warning and Winter Weather Advisory is in place for parts of the Texas Panhandle, southwestern Kansas, and northwestern Oklahoma. It is possible these winter weather products get extended farther south and east on Wednesday.