Why Storm Force 31 Forecast is Colder than Others
As was expected in the Fall and discussed during the Winter Outlook, this winter has been colder than normal with an increased chance of seeing snow/ice in the southern U.S. and especially the Tennessee Valley. Friday’s most recent bout with wintery weather is likely not the last as February is setting up to be another cold and active month.
The next few days will be rather quiet with high pressure building into the Southeast. With the fresh snow pack along the I-40 corridor and a northerly breeze flowing across it, morning temperatures will be on the cold side. A few areas, especially through southern-middle Tennessee into extreme northern Alabama will likely see some low temperatures into the teens while further south they will be in the low 20s. During the afternoon’s (Sunday/Monday) we will see quite a bit of sunshine.
An “Alberta Clipper” will help to deliver some reinforcing Arctic air to the north of the Valley, Monday through Wednesday. With the “Clipper”, a band of accumulating snow is anticipated along and north of the I-80 corridor from Nebraska to Pennsylvania. Snowfall is not expected to be extreme but there will likely be a wide swath of 2” to 4”. This will help to provide an almost continuous snow cover from just south of the Ohio River northward to Canada, nearly the entire northeastern quadrant of the U.S.! This is important because snow cover helps to aid in cold air maintaining itself as it slides south out of the Arctic region.
As the “Clipper” moves through the Valley on Tuesday morning, a few sprinkles are anticipated. Temperatures at the time will be in the 30s. Some locations may be near freezing so some patchy slick may occur. This IS NOT anticipated to be a storm of any major consequence for the Southeast and the Tennessee Valley! The “Clipper” will move off the Mid-Atlantic coast by Wednesday morning with a cold front clearing the entire Southeast, even the south tip of Florida. Some reinforcing Arctic cold will slide into the Southeast; however, it is not anticipated to be sharp shot of cold but it will allow temperatures in the mornings to fall back below freezing as far south as the Tennessee river towards the end of the week.
Attention will then turn to the Southwestern U.S. where another storm system will move ashore associated with the subtropical jetstream. This system will spread more rains and mountain snows to the western U.S. from Canada into the desert Southwest on Tuesday and Wednesday. This upper level energy will begin to aid in the development of a surface storm system northeastern “Old” Mexico by Thursday morning. In its advance, a southerly flow will set up and produce a solid fetch of Gulf moisture that will encompass much of the Gulf coast from Texas to Florida by Thursday morning.
From this point forward, there are several solutions being shown by weather modeling data. I have decided to follow more closely a model known as the “European” model or ECMWF versus the American long range model, Global Forecasting System (GFS) or the Canadian model. Why? Over time I have learned to have more confidence in the ECMWF as a long range model, being consistently more accurate. In addition, it did a pretty good job with regards to the forecast several days out with the Friday weather event. So as I continue and mention location and timing of systems for late this week note it is nearly the solution being indicated by the current ECMWF. Other forecasts you will likely see the next few days will likely be based more closely on the GFS and for that reason the Storm Force 31 7-day forecast will likely be a bit different.
The surface low that is forecast to develop over “Old” Mexico is forecast to track to the northeast Thursday into Friday across the Gulf of Mexico and moving to a location south of New Orleans by Friday morning. At the same time an Arctic high pressure will be sliding east out of the Ohio Valley into the Mid-Atlantic. A wedge of Arctic air is likely to get caught up against the eastern face of the Appalachians from North Carolina into northern Georgia. Will the cold air remain in place over the Tennessee Valley? That will have to be watched as we get closer to the event. Because widespread rain is likely to overspread the entire Southeast by Friday morning. In fact, the northern edge of the precipitation shield may make it as far north as the Ohio River by sunrise Friday. It would appear that conditions would most likely be favorable for “Rain” as the precipitation type even as far north as the Ohio River. However, at the surface, I do believe temperatures will be at or below freezing for a period for the eastern facing Appalachians due to a scenario we call in meteorology as “Cold Air Damming”.
As was expected in the Fall and discussed during the Winter Outlook, this winter has been colder than normal with an increased chance of seeing snow/ice in the southern U.S. and especially the Tennessee Valley. Friday’s most recent bout with wintery weather is likely not the last as February is setting up to be another cold and active month.
The next few days will be rather quiet with high pressure building into the Southeast. With the fresh snow pack along the I-40 corridor and a northerly breeze flowing across it, morning temperatures will be on the cold side. A few areas, especially through southern-middle Tennessee into extreme northern Alabama will likely see some low temperatures into the teens while further south they will be in the low 20s. During the afternoon’s (Sunday/Monday) we will see quite a bit of sunshine.
An “Alberta Clipper” will help to deliver some reinforcing Arctic air to the north of the Valley, Monday through Wednesday. With the “Clipper”, a band of accumulating snow is anticipated along and north of the I-80 corridor from Nebraska to Pennsylvania. Snowfall is not expected to be extreme but there will likely be a wide swath of 2” to 4”. This will help to provide an almost continuous snow cover from just south of the Ohio River northward to Canada, nearly the entire northeastern quadrant of the U.S.! This is important because snow cover helps to aid in cold air maintaining itself as it slides south out of the Arctic region.
As the “Clipper” moves through the Valley on Tuesday morning, a few sprinkles are anticipated. Temperatures at the time will be in the 30s. Some locations may be near freezing so some patchy slick may occur. This IS NOT anticipated to be a storm of any major consequence for the Southeast and the Tennessee Valley! The “Clipper” will move off the Mid-Atlantic coast by Wednesday morning with a cold front clearing the entire Southeast, even the south tip of Florida. Some reinforcing Arctic cold will slide into the Southeast; however, it is not anticipated to be sharp shot of cold but it will allow temperatures in the mornings to fall back below freezing as far south as the Tennessee river towards the end of the week.
Attention will then turn to the Southwestern U.S. where another storm system will move ashore associated with the subtropical jetstream. This system will spread more rains and mountain snows to the western U.S. from Canada into the desert Southwest on Tuesday and Wednesday. This upper level energy will begin to aid in the development of a surface storm system northeastern “Old” Mexico by Thursday morning. In its advance, a southerly flow will set up and produce a solid fetch of Gulf moisture that will encompass much of the Gulf coast from Texas to Florida by Thursday morning.
From this point forward, there are several solutions being shown by weather modeling data. I have decided to follow more closely a model known as the “European” model or ECMWF versus the American long range model, Global Forecasting System (GFS) or the Canadian model. Why? Over time I have learned to have more confidence in the ECMWF as a long range model, being consistently more accurate. In addition, it did a pretty good job with regards to the forecast several days out with the Friday weather event. So as I continue and mention location and timing of systems for late this week note it is nearly the solution being indicated by the current ECMWF. Other forecasts you will likely see the next few days will likely be based more closely on the GFS and for that reason the Storm Force 31 7-day forecast will likely be a bit different.
The surface low that is forecast to develop over “Old” Mexico is forecast to track to the northeast Thursday into Friday across the Gulf of Mexico and moving to a location south of New Orleans by Friday morning. At the same time an Arctic high pressure will be sliding east out of the Ohio Valley into the Mid-Atlantic. A wedge of Arctic air is likely to get caught up against the eastern face of the Appalachians from North Carolina into northern Georgia. Will the cold air remain in place over the Tennessee Valley? That will have to be watched as we get closer to the event. Because widespread rain is likely to overspread the entire Southeast by Friday morning. In fact, the northern edge of the precipitation shield may make it as far north as the Ohio River by sunrise Friday. It would appear that conditions would most likely be favorable for “Rain” as the precipitation type even as far north as the Ohio River. However, at the surface, I do believe temperatures will be at or below freezing for a period for the eastern facing Appalachians due to a scenario we call in meteorology as “Cold Air Damming”.
ECMWF forecast for Friday morning, Notice Low south of New Orleans
By Saturday morning the low is forecast to continue to track northeast and be located near Norfolk, Virginia. In addition, a second piece of upper level energy is forecast to drop southeast out of Canada and merge with the system. This track and additional energy would take abundant rainfall up along the East Coast of the U.S. with snow likely into the Ohio Valley and as far west as possibly the Mississippi Valley and as far south as the Tennessee Valley.
As a result, this will be another storm system to monitor this week. Could the Tennessee Valley and others in the Mid-South see another round of ice/snow setting up the potential for two events in just a week? Yes, possibly. Obviously, the old adage must be restated, “It is still several days out and a lot can change. The track and strength of the storm system will greatly determine where and if any wintry precipitation occurs.” Based on recent trends and indicators I have been monitoring, I do believe this is good potential solution but only time will tell us for sure.
Now, quickly, what do the other models say. Well, both the Canadian and the GFS show a Gulf system moving northeast out of the Gulf of Mexico. The operational GFS is a bit faster and further east with the system over time while its Ensemble is a bit slower, further south and then further west and is in between the operational GFS and ECMWF.
GFS Image for Friday AM, Notice Low is Over NE Florida
Well, that is enough for now. Stay tuned through the week for the latest forecast.
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