Multiple Strong Cold Fronts; High Pressure and Deer Movement (10/23/17)

The best hunting weather of the season so far is about to make its way into the country this week. Multiple strong cold fronts are expected to move through over the course of the next week or so. The midwest will see the biggest impact from the first front, with the fronts that follow bringing big temperature drops to most of the country east of the Rockies. Many areas will see their first freeze of the season this week all the way down to the southern plains.

In this forecast discussion I want to also talk about something I have been getting questions about lately. And that is how high pressure affects deer hunting. I will discuss this at the bottom after the forecast.

If you’ve been riding the October lull the past couple weeks, activity may finally break open following these fronts to really get the beginning of the rut kicked off. I’ve seen many photos online of mature bucks down that came through already chasing does. If you live in the northern states, you’re pretty much on the rut’s doorstep if not getting into it. Let’s get into the weather.


As I said above the big story this week is two, possibly three strong cold fronts, with one of them already making its way across the country at the time of this writing. The midwest will see the biggest impact from the first front as highs will remain in the 40s for this area through at least Wednesday morning. However, morning lows will be in the 30s and low 40s for many parts of the country by Wednesday morning but the daytime highs for the plains will still get into the 50s, 60s, and 70s through Wednesday afternoon. Here’s a loop of what this will look like according to the NAM model:


Remember that times are shown in the upper right corner, with 12z being 7am CDT and 00z being 7pm CDT. So 00z Thursday is actually 7pm CDT on Wednesday. It’s a weird time convention that’s supposed to help make time consistent across the world for scientists and government entities. If you want to see a chart of Zulu (UTC) time conversions you can find that here.

The front that comes behind this one is going to bring the big multi-day cool down for most parts of the country. At the time of this writing the evening run of the NAM model is still coming in, so we need to look at the most recent run of the GFS model to see this far:


We can see that, according to this model, many areas struggle to get above the low 50s for several days after this front moves through with maybe the exception of parts of the southern plains could possibly get into the low 60s next Sunday. By next Wednesday we can see that some warm air begins to push in from the south again. This happens at well over 200 hours out in the model, which you’ve heard me say before is getting into model fantasy land. Your guess is nearly as good as mine as to what could actually happen at that point. That would be getting into the first of November, which would be unfortunate timing for those hunting hard during the rut. But let’s not get too worried about it just yet because we can’t say for sure. Moral of the story is there are multiple days coming up that should be great hunting temperature-wise. Let’s make the most of it!


The Great Lakes region is currently getting a fair amount of rain from the low pressure system that is moving across the region. This will likely continue into Tuesday and possibly early Wednesday. The east coast will also see some rain over the next few days with the north east getting some fairly substantial rainfall. Below is a map showing total rain accumulation through Thursday:


The rain in the Great Lakes should mostly taper off by Wednesday, with the rain in the northeast moving out on Thursday. Then as the next front moves through it will bring another chance of rain to the Great Lakes and eastern states as it moves through. Below is another map showing expected precipitation totals over the weekend (Fri-Mon):


The second front that moves through should bring at least a slight chance of snow with it to the northern states. It will be plenty cold enough there and there will be precip in the forecast. Tough to say this far out but if I had to guess who might see snow I would say northern Wisconsin and possibly parts of Minnesota, with other northern states maybe getting a dusting.

Pressure Changes and Deer Movement

I’ve been getting a few questions lately about how pressure changes affect deer. While I don’t claim to be an expert on deer, I want to offer my opinion on this subject because it comes up fairly often.

Usually when I hear deer hunters talk about pressure they say something like “we had a cold front push through last night, and the pressure is really high today.” Many hunters talk about high pressure as something separate from other weather factors that influence deer movement. You may think I’m crazy, but I really don’t believe that deer pay any attention to pressure because they don’t have any way of doing so. Deer, with the exception of a gall bladder and a 4-chambered stomach, possess essentially the same organs that we do. They don’t have any organs dedicated to detecting pressure changes, such as an “Organ of Weber” commonly found in fish. With this in mind, I don’t see how there is any way they can actually tell whether or not there is high pressure.

It’s no surprise to me that hunters have long associated high pressure with good deer hunting. In the fall, cold fronts almost always result in increasing pressure behind them. This is because the cold air behind the front is sinking, causing high pressure at the surface. We all know that cold fronts will usually get deer up on their feet (it’s the whole premise of this website’s title), and this is because it drives them to feed.

Knowing all of this, it makes the most sense to me to focus on the big temperature changes when you are looking at the weather for your next hunt, and not so much on the pressure. If you have a cold front moving through, the high pressure will follow.

If it can stay dry, I should have a few days this week that I can get out. Temperatures are going to be great for it.

Good luck.

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