Snowy Veteran's Day?
by Kelly Smith, Meteorologist
November 06, 2012 11:14 AM
A potent cold front is poised to move through our region this weekend. Today's KDLT Weather Blog discusses why this storm is still "up in the air."
Just last week Hurricane Sandy was making headlines and introducing the national television audience to the European Weather Forecasting Model. The weather forecasting model which is a household name to Meteorologists received quite a bit of press last week from the national media as it proved to most accurately forecast the track of Hurricane Sandy. Even the Today show took some time to give credit where credit is due .
The KDLT Weather team uses many models including the European model to forecast and the majority of the time the models disagree on a solution. Often times this is the case when a big weather system is forecasted to move into the area. A slight difference of a few hundred miles could mean the difference between feast and famine in the weather department, which is why knowing the differences in the forecast models, becomes important.
One of our long-range models has been showing a significant storm system for Veteran's day weekend since last week, however long range models tend to rely more on "history" rather than actual conditions and this makes long range models fairly inaccurate. As Meteorologists we watch everyday how the models change in order to get an idea of which model will be more accurate. Often times we will merge two or three solutions to come up with our own forecast. This is why many Meteorologists will come up with many different solutions.
As we get closer in time to our "storm" models tend to become more accurate. Short-range models tend to be more "sensitive" to our unique local effects, which allows them to in theory be more accurate. Our in-house futurecast is one of those short range models and does very well in our area however it only goes out around 72-hours in advance.
We are getting closer to the weekend and our weather forecasting models are getting closer to coming up with a more accurate solution for this weekend's storm. There are still many factors that are up in the air, like actual placement and timing of the front but much like Hurricane forecasting the cone of uncertainty will become smaller as we get closer.
Tuesday morning the track between two of our long-range models became closer however, the difference between the two will still lead to two very different scenarios.
The GFS Weather Model takes a more northerly route through much of southeast South Dakota which would likely put a majority of the eastern half of the state in what we call the "dry-slot".
(GFS model valid Saturday morning) The positioning of the low towards our southwest Saturday morning would bring in warm, dry air to much of the eastern half of South Dakota which is commonly called the "dry-slot" because precipitation does not form. The majority of the precipitation would form to the northeast of the low pressure center, keeping the majority of the precip west of South Dakota.
(GFS model valid Saturday evening)By Saturday evening the low pressure would slowly move northeast and separate into two low's: one to our northeast and one in our southeast. At this point the cold front would be situated in northwest Iowa and moisture behind the front would be limited keeping the majority of the rain east of our area.
(GFS Model around midnight Saturday night)By around midnight a line of precipitation will form behind the front but as it will have limited moisture the precipitation which does end up falling will likely be very small and very brief. At this point as well it would be possible to see some change over from rain to a rain/snow mix. The aqua line would likely be close to the rain/snow line.
(GFS Model Sunday Morning)Any snow or rain/snow mix will likely be very brief so snowfall/rain totals will likely be very minimal with this solution.The European model is similar to the GFS in that it takes the system through our area however a more southerly route would result in a far different solution.
(European model Saturday afternoon)In contrast the European model brings a fairly strong split low scenario slightly farther south of the GFS. The Euro would swing a cold front through around the same time as the GFS Saturday night but a slightly southern track would allow better chances for less "dry-slotting".
(European model Sunday evening)Another stark difference is the extent of the low exiting our region. The European quickly moves the low into Canada, which would essentially create a "vacuum" over our area allowing very cold dry Canadian air to surge into our area. While both models show a very significant cold blast, the European would indicate the coldest weather so far this season.The differences between the two model tracks are easily seen when they are tracked together.
By Friday evening the two systems will form off west, with the Euro slightly southwest of the GFS.By Saturday afternoon/evening the European has moved significantly north while the GFS lags behind in northeast Colorado.Saturday afternoon the GFS moves very quickly northeast through south central South Dakota and ending into northern Minnesota while the Euro takes a more easterly track across our southern boundary with Nebraska ending in southwest Minnesota.Both models do have the systems exiting our area very quickly but the more extreme European would allow for more cold Canadian air to move in.At this point it is still safe to say that the chance for rain and a rain/snow mix is pretty good. What we will be watching over the next few days is how these tracks change and from there we will be able to tell how much and what type of precipitation will occur. It is also safe to point out that the cool down Sunday and Monday will be significant with some of the coldest air of the season.Election Day will be a breezy, blustery day but clear skies will make for a pleasant day. The majority of the country will stay dry with the exception of the south and east. This is a great article looking into how the weather can affect the election.The ridge of high pressure will bring a short warm up Wednesday and Thursday with the warmest day of the week on Thursday before our system makes its way into the region. As always, stay tuned to KDLT for updates on the upcoming Veteran's Day storm.