Just as the title says, this is going to be a tricky forecast. I am referring to the upcoming winter storm.Models are not in agreement for a lot of ingredients with the storm. I am feeling pretty confident with the timing of the storm. I think it will begin to impact the KFVS viewing area starting Monday afternoon. The storm will then spread east/northeast paralleling the Ohio River. The storm should be out of the area by Tuesday late-morning.I posed a few questions yesterday morning that needed to be answered so we can forecast the storm. - Track of the storm?
Answer: There is not complete agreement as to the track of the storm in all of the models. The majority of the models seem to be shifting the storm a little further south. This means we should be able to draw in plenty of cold air. In fact, if this holds true, snow will be an issue further south than originally thought. This means there could be an accumulating snow from northeast Arkansas through the Missouri bootheel in to western Kentucky.
There is one outlier. The NAM keeps the storm on more of a northerly track. If this were to pan out we would see more rain and the rain could slide further north. - Temperature profile in the atmosphere?
Answer: For the northern half of the KFVS viewing area (southeast Missouri, southern Illinois, western Kentucky, and northwest) all precipitation should fall as snow. The southern half is a little more tricky because of the answer to question 1. If the storm tracks further south then snow would be a problem for southern counties. - Will dry air be in place?
Answer: It will be dry but not as dry as the storm from two weeks ago. As of 11:00am CT, dew points are in the upper teens to lower 20's. Winds will be out of the northeast/east today. That means we will draw in air from southern Indiana and central Kentucky. Their dew points are in the upper teens. So there will be some dry air to overcome initially, but it should "eat" our snow like it did last time.
Now for the big question. How much? Extremely tricky especially since the models continue to flop back and forth as to how much liquid there will be to work with. For example, last night's 0z run of the NAM model put down around 0.6" of liquid for Cape Girardeau. This morning's run is showing 0.25". Potentially, that is a huge difference. That is the difference between at a minimum 4" of snow.Here is what this morning's NAM run is showing for snow accumulation.
To contrast the above numbers with the NAM I decided to take a look at a couple of other models that most don't look at. The Canadian weather agency's model and the United Kingdom's model.
0z Canadian run:Liquid:- Cape Girardeau: 0.59"
- Farmington: 0.51"
- Harrisburg: 0.43"
Snow: - Cape Girardeau: 5.9"
- Farmington: 5.5"
- Harrisburg: 4.2"
12z Canadian Run:Liquid: - Cape Girardeau: 0.55"
- Farmington: 0.59"
- Harrisburg: 0.39"
Snow: - Cape Girardeau: 5.3"
- Farmington: 5.9"
- Harrisburg: 3.5"
0z UKMET Run:Liquid: - Cape Girardeau: 0.11"
- Farmington: 0.17"
- Harrisburg: 0.08"
Snow: - Cape Girardeau: 1.2"
- Farmington: 3.1"
- Harrisbug: 0.8"
This gives you an idea as to how models are all over the place right now. So confidence in any given amount is not very great at this time. It still appears to me that a 4"-8" snow is possible. Where exactly? Still too tough to call. It will depend on where the rain/snow line sets up. The heaviest snow should occur just to the north of the rain/snow line.Here is a look at what the forecasters with the Hydrometeorological Prediction Center are thinking. This is a probabilities forecast.
I will try to update later today, but to be honest my attention is going to be on the Super Bowl airing on KFVS12. In case you haven't been following my blog, I am originally from Indiana and I am a HUGE Indianapolis Colts fan. Needless to say, I have interest in this evening's game.
A quick update tonight...New data coming in from the 0z runs and it still looks like our storm for Monday/Tuesday is on track. As is usually the case with winter storms, we will see the rain/snow line sitting over parts of western Kentucky and southeast Missouri. North of that line there could be some heavy snow. I don't think it is out of the realm of possibilities that we could see a 4"-8" snow from this storm.One trend to take notice of... The models seem to be slowing the storm down. Not too big of a surprise as every storm this winter has been that way. As of right now it looks like moisture will start to hit the ground starting early Monday afternoon.
Forecast focus continues to be on Sunday night through Tuesday morning. This is when the next winter storm will impact southeast Missouri, southern Illinois, western Kentucky, northwest Tennessee, northeast Arkansas, and Indiana.Computer models are developing a surface low pressure area over the southwest United States tonight. This low will move east through New Mexico --> southwest Texas --> Dallas --> northern Louisiana. After northern Louisiana, it begins to split the storm. One moving northeast. The other staying south along the gulf coast. Generally, this is a pretty good track for heavy snow for southeast Missouri and southern Illinois. However, the models are trending a little further north that could take the heaviest band just north of the KFVS viewing area. A more northerly track would also mean slightly warmer air being brought in to play.Lets look at the data from the models. I always have to remind people reading the blog that the following information is data straight from the models. The below numbers are NOT the forecast. Often times the forecast will differ from one specific model.Here is an overall look at NOAA's global forecast model (GFS):
The graphic shows accumulated snowfall through Tuesday evening. The GFS has handled things pretty well this winter with the exception being the winter storm to hit Indiana yesterday.Here is a closer view of what the GFS is suggesting:
You note the grey box above. I believe that is a "burp" in the rendering of the graphic and is just missing data in that area.Lets now move on to one of the other models run by NOAA. The NAM:
Something interesting to notice in this run of the NAM. It puts a heavy bulls-eye of snow over north central Arkansas. This doesn't look out of question to me as that would be the area where the surface low would be most concentrated before "splitting".Here is a closer in view of the NAM model for the KFVS viewing area:
You can see in the NAM that it is taking more of a northerly track with the storm. This is noticeable due to the lack of snow over Tennessee and western Kentucky.Specific locations.... Again, these numbers come straight from the computer models. These are not the forecast.- Cape Girardeau, Missouri: NAM = 5.5" GFS = 3.4"
- Farmington, Missouri: NAM = 4.8" GFS = 6.0"
- Paducah, Kentucky: NAM = 4.6" GFS = 3.4"
- St. Louis: NAM = 5.2" GFS = 6.2"
- Indianapolis*: NAM = 3.5" GFS = 9.0"
*The storm would impact Indianapolis late Monday through Wednesday.There are still several questions in place as for the amount of snow we will get.- Track of the storm?
- Temperature profile in the atmosphere?
- Will dry air be in place?
The final question in the three above is an interesting one. The big storm in the KFVS viewing area had dry air in place to begin with. Dew points were in the single digits. As I type, dew points are in the middle 20's. So we should be in better shape (if you want snow) to start with as opposed to the last go around.Stay tuned...
Temperatures are still relatively warm in southeast Missouri, southern Illinois, western Kentucky, and northwest Tennessee.Below is a look at surface observations around the Midwest at 4pm CT.
For us to start talking about an accumulating snow we are going to need to get our temperatures down. So far today, temperatures have been slow to cool. In fact, temperatures through the central and southern part of the KFVS viewing area has remained stationary all day.A Winter Weather Advisory continues for the counties listed on the previous post through Saturday morning.At this point, I'm not too bullish on the snow potential around the area. All models indicate that we should be all snow at this point. I just stepped outside and there were a few rain drops still falling.Temperatures should begin to fall off later tonight. As they do so, it will be easier to work some of the snow down to the surface. There is a better chance for snow the farther north you go.
The National Weather Service in Paducah, Kentucky has expanded the Winter Weather Advisory to cover some of their counties in southeast Missouri and southern Illinois.
The Winter Weather Advisory will be in effect from noon until 3:00am CT Saturday. In the advisory they talk about a change over from the rain to snow later this afternoon, also mentioned a couple of blog posts ago. Snowfall amounts could be 1"-3".
How much snow will be greatly dependent on surface temperatures. As of 10am CT, temperatures across southeast Missouri and southern Illinois are in the middle to upper 30's. (Farmington 36° | Cape Girardeau 39° | Carbondale 39° | Harrisburg 37°) Temperatures on the backside of the storm have dropped to freezing. (Sedalia, Missouria 32°)
For the Indiana folks.... Snow forecast for Friday through Saturday is looking a bit more difficult. New data coming in is wetter than other data was showing 12 hours ago.Here is a breakdown of how much liquid there is to work with across central Indiana from four different models.- NOAA's global forecast model: 0.43" (morning data)
- United Kingdom's forecast model: 0.67" (new data)
- NOAA's regional forecast model: 1.00" (new data)
- Canadian Meteorological Agency's forecast model: 0.82" (new data)
In a general sense you can look at a 10:1 snow to rain ratio. During the Friday/Saturday storm there will be times when it will be coming down at a 8:1 ratio and other times when it could be as high as a 12:1 ratio.Which model is correct at this point? It is hard to tell. (I am glad I am not on-air in Indy having to forecast this one.) I am thinking that the snowfall numbers I mentioned earlier need to be adjusted up some.It appears that for central Indiana tomorrow morning will start out with a freezing rain/sleet mix (ice should be no more than 0.1" and more likely less than 0.05"). Then a change over to snow. Some of the heaviest snow could fall during lunch hour (11am-2pm ET). Snow will likely continue through the evening and in to Saturday morning.Overall, the heaviest snow should be in east-central Indiana. Perhaps the heavy snow band setting up NW of Indianapolis from Lafayette to south of Kokomo to Anderson and over to Dayton. That band can easily shift north/south depending on the track of the storm.
