A Plethora of Winter Storm Potentials to Monitor

Ice storm potential next week

Synopsis

A longwave trough with quite a broad base will remain almost stationary across the northern half of the U.S. this upcoming week into at least next week. A ridge will persist just off the West Coast, while a block sits over western Greenland. Another ridge will remain positioned over the southeastern quadrant of the U.S. This ridge will initially keep temperatures well above average across the Southeast; however, northern troughing will prohibit the ridge from amplifying unabated. A baroclinic zone will become established across the Southern Plains, Mid-South, Missouri Valley, Tennessee Valley, Southeast, Ohio Valley, and Mid-Atlantic. This setup will bring several opportunities for snow, ice, and rain across the mentioned regions over the next two weeks.

We discussed around a week ago how longwave troughing can suppress the storm track too far southward to bring any meaningful wintry precipitation. Instead, conditions are generally very dry and cold. If you recall, model guidance had a lobe of the tropospheric polar vortex digging as far south as the Tennessee Valley for early this week. Instead, we got a flatter trough with some Southeast ridging. In most guidance now, we’re stuck with a long-lasting broad-based trough that likely won’t keep the southern stream storm track suppressed.

Temperature outlook february 14-18, 2021
Probability of above/below average temperatures over February 14-18, 2021

Cross polar flow extending from Siberia over into western Canada has allowed Arctic air to pool over western Canada. That brutally cold airmass has already begun spilling into the upper Plains and Midwest. But essentially, we now have the available cold air to tap as numerous storm systems parade from the Southwest/Southern Plains in an east or northeastward direction. One major drawback to the expected pattern configuration is that ice (sleet/freezing rain) could become the more predominant frozen precipitation-type across the Southern Plains, Mid-South, Southeast, and even into the lower Ohio Valley and Mid-Atlantic. With broad troughing centered across the central U.S. and a Southeast ridge to the east, southwesterly flow will transport warm air above the surface. However, Canadian high pressure will wrap around very cold air at the surface. This will produce atmospheric profiles that support sleet/freezing rain versus snow.  

Systems We’re Currently Watching

We have a slew of systems we’re currently watching that will bring impacts in the foreseeable future. We’re going to post articles and social media updates on each system individually, but we will introduce those threats here.

February 10-12, 2021 (Wed.-Fri.): Shortwaves embedded in mostly westerly flow will bring widespread precipitation across the Southern Plains, Mid-South, Missouri Valley, Southeast, Tennessee, along and south of the Ohio River, and the Mid-Atlantic. Canadian high pressure has continued to advect cold air at the surface across northern portions of where precipitation will develop. We expect a prolonged period of sleet/freezing rain to fall across northern Texas, central/eastern Oklahoma, northern/central Arkansas, lower Missouri, western Tennessee, upper Mississippi, and Kentucky. North of the Ohio River and areas across much of the Mid-Atlantic will experience mostly snow, although lower and central parts of the Virginias may get a mixture of snow/ice. For areas south, expect rain.

February 13-14, 2021 (Weekend): Forecast model guidance indicates HIGH uncertainty for this potential event. The outcome of this potential winter storm depends on the interaction of three features: a shortwave entering lower California late week, a shortwave entering the Pacific Northwest around the same time, and a lobe of the tropospheric polar vortex spinning over the northern Plains/Midwest. The European model continues to indicate that the California wave gets suppressed so far south that it passes across the Gulf of Mexico. This feature would bring rainy conditions to Florida and areas along and relatively close to the Gulf coast over much of the weekend. On the other hand, the GFS often has the California wave phasing with the Pacific Northwest wave somewhere over the central U.S. This scenario would result in the phased systems eventually taking on a northeastward trajectory. This scenario would potentially bring a significant winter storm to the central/southern Plains, the Mid-South, the Missouri Valley, the lower Midwest, the Ohio Valley, the lower Great Lakes, and Northeast over the weekend. I will admit that this is a tough forecast, and at the moment, I need additional time to study this event.

February 15-17, 2021 (Mon.-Wed.): A strong shortwave will enter the western U.S. later in the weekend and dig southeastward into the Four Corners region. As the wave continues eastward, the tropospheric polar vortex lobe will move eastward across the Great Lakes and Northeast. These two features will create a region of confluent flow across the Ohio Valley and Mid-Atlantic/New England, which will support Canadian high pressure moving eastward into the Northeast. This high will likely result in cold air damming as far south as the Carolinas and Georgia. A surface low will likely develop along the Gulf coast in response to the shortwave approaching the region. Cold air will already be in place across the Southern Plains, Mid-South, and much of Tennessee to support wintry precipitation. With cold air damming in place, the Carolinas, northern Georgia, and northeastern Alabama need to closely monitor the potential for an ice storm next week. This system could potentially bring an impactful winter storms to parts of the Ohio Valley, Mid-Atlantic, and (maybe) the Northeast. We have about a week to get into specifics. I advise against making any changes to current plans until confidence increases over the next two to three days.

2 storm chances for East Coast

The Southern Storm is the big story with winter weather expected to impact from Texas to the Eastern Seaboard, leaving the first storm expected to form off the coast of the Carolina’s pretty much no attention attention.

 

This weak system is expected to slide up the coast and bring some rain to Eastern North Carolina with light snow from areas of Nebraska into Kentucky to Delaware and New Jersey ahead of the Southern Storm.  Matt has posted a handy map of the Winter Weather Advisories that are currently in place as this weak system moves across the country toward the coast.   This system will combine with the low shown above and slowly intensify as it moves to the Southeast of New England.  This system will bring snow into Southeastern New England with light accumulations during the early morning hours of Friday into Friday afternoon.    Early activity will likely be in the form of snow showers which may limit to coverage area of overall snowfall but the biggest problem to accumulating snow will be the warmth of the ground.   Any snow that does manage to stick will have a difficult time remaining in place for long, with the one thing that may save some areas from an instant melt being the cold temperatures on the way following this system.

Southern Storm

For the main event, which have been covered well by Chris and Matt for the Southern areas that’s will be impacted, the Southern storm looks like it’ll be wide right for many of our readers.  As seen in the previous articles, the system forms in the South and slides off the coast of the Carolina’s, leaving the heavier snow totals expected for that region.  the uncertainty in the speed and exact track of this system is causing some forecast issues, but aside from some lake effect snows  caused by the general flow pattern in the Great Lakes region, this second system looks to leave readers across most of Kentucky, West Virginia, Western and Central Pennsylvania back towards Ohio high and dry.

Southern Storm

The above model data is for 1 PM Saturday.   It shows the storm after it has left Georgia and areas further west and does not indicate that it will not snow there at all.  Just that it will not be snowing there at this particular point in time.

Watching the strength and track

The key question to the track of this system will be the strength of the lows and the energy brought into the pattern.  A strong set up will include more of the Eastern portions of the U.S while a weaker pattern will deprive even New England of any snowfall.  Despite the impressive moisture associated with this system, guidance is now really strengthening these lows very much.   For anyone along the Mid-Atlantic and Northeast, please read the articles Matt and Chris put out about the south to stay informed about this system.   The information they have will be invaluable for track this system up the coast over time.   I’ll be around to keep you up to dat on all the latest for this system and its impacts for this region.   So keep an eye on both facebook and the website for further details.

 

Robert Millette

Firsthand Weather

Southern Plains and Mid-South Winter Storm

We have yet another tricky winter storm forecast on the table for tomorrow going into early next week. This active pattern is about as locked in as it gets, and although there are signs that we may try to snap out of it sometime in March, we still have at least 7 to 10 days with this cold and active pattern, maybe more. It’s a lot of work forecasting these individual storms, and as much as I love it, a small break would be nice. 🙂 Anyway, let’s jump right into it.

I wrote on Facebook earlier about how these active patterns can bring surprise winter events. While it won’t be a surprise for the Southern Plains, I really wouldn’t be shocked if regions farther east got wintry precipitation also earlier next week. The Rockies are currently getting the kind of snowfall they haven’t seen all winter, and the precipitation will eventually spread and develop into the Southern Plains tomorrow into Monday.

Southern Plains and Mid-South Winter Storm:

A strong Canadian high pressure system is going to be pushing south into the United States tomorrow and will be wrapping around very cold air with it. The first round of precipitation will move into the Southern Plains tomorrow, bringing wintry precipitation into the western half of Kansas, the panhandles of Oklahoma and Texas and eventually spread eastward into parts of Oklahoma, Arkansas, and maybe northern parts of Mississippi and Alabama (maybe including Birmingham) on Sunday night into Monday. I’m thinking that regions from Dallas southward should just have rain tomorrow, but then things get very interesting early Monday morning into the afternoon.

More precipitation will be developing on Monday, and regions from a large part of Oklahoma into Arkansas and southward into Texas and northern and central Louisiana will be dealing will a snowy and icy mess. This includes Dallas, Austin, and maybe even as far south an San Antonio. This will be a widespread event that will make traveling impossible for some areas, especially where sleet and freezing rain fall. The wintry precipitation could spread into parts of Mississippi and Alabama once again.

The NAM has snowy and icy conditions developing across the Southern Plains early on Monday, eventually spreading eastward into the Mid-South later in the day. (I’ll keep an eye on that region over North Carolina, just in case something comes up.)

dallas winter weather

Winter Storm Surprise For The Southeast?

I’m going to include this because I know how these kind of active and cold patterns are. Forecast models just don’t handle these types of setups well, meaning a surprise or two can happen. Now please understand that this is NOT the winter storm threat that I am monitoring for late this upcoming week into the weekend.

As high pressure begins to move south and eastward early this week, another cold air damming scenario could set up east of the Appalachians. Many surprise winter events have occurred as a result of this, and again, forecast models often miss these. IF (take special note of this condition) moisture spreads far enough north anywhere from Tuesday into Wednesday, then there COULD be an unexpected winter storm across states like Georgia, South Carolina, and North Carolina. The unpredictability of the weather means there are various hazards that many people could across which could cause accidents and injuries, especially if the proper precautions aren’t put in place to prevent accidents. If you find yourself a victim of an accident that wasn’t caused by you, it might be worth looking into someone like these Smyrna, GA personal injury attorneys who might be able to help your case.

You can see where the NAM develops snow and icy weather over parts of the Southeast. I’m watching that VERY closely.

southeast winter storm

Right now, forecast models suppress the moisture farther south after it works its way eastward from the Southern Plains and mid-South. With how things have gone so far this winter, I wouldn’t be surprised if moisture tries to come farther north due to low pressure system tracking farther north. I’m just throwing this potential out there and want you to be aware that this is a possibility that could catch many off guard. I just have a difficult time seeing that system going that far south, but it may. I just need to keep a close watch on it.

Robert Hanson from Olney, MD shared this photo today! He said that was about 9 inches of snow.

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