 Welcome to Longmont Public Media's forecast discussion for Thursday through Saturday, February 20 to 22. I'm Chief Meteorologist John Insworth. I'm going to be taking you through the story of Longmont's weather with just a little more science. Let's start with the moon Saturday night. We have just a little bit of a visible 7% or so. It's a little crescent in the pre-dawn sky rising at 5 a.m. that long before sunrise itself. In about three days it'll be hidden by daylight sky and then returning to the evening to join Venus. So I'll make a nice show in a week or two. So let's start with Wednesday's upslope storm. It wasn't much of a storm. Very light flurries throughout the day. It kind of got a little stronger at night as the cold front came in. Coming into Thursday now we have high pressure system settling down behind this front. You can see the front extending down into Texas and Arizona, southern New Mexico. And the air around the high goes clockwise. And we have sort of a double barreled high here. So it's sort of going in a figure 8 shape. But that means the easterly flows on the south side of these two high pressure centers. And that is the upslope flow and the flow of moisture over the cold air that's creating all this wintery mix. Largely out on the plains up near the foothills and down southeast Colorado. I think I'll load it later on Thursday. You can see the highs have moved down into Kansas and Iowa. And the flow now is down into west Texas and New Mexico much more than Colorado. Everything peters out and begins to clear pretty quickly on Thursday. So what we're going to look at is this cold period now going into the end of the week. We're staying below freezing for a couple days. And the weekend is going to be really warm. Temperatures getting up close to 50 degrees. Even in the beginning of next week we're still in the 40s so we'll get some melting. What's pretty significant here is with the blue dotted line being the freezing line. Tonight we just get down to freezing. So this could be a way to get rid of some of this icy junk left around by the previous few storms. There's a little bit of something here on Sunday. It's going to bring some precipitation in but you can see temperatures are not really cold so it may not be very snowy. Then the bottom drops out Monday with another big front coming in and temperatures stay far below normal. And we have many different model runs and it's called the GFS Ensemble. All different runs of the computer where things vary a little bit. Looking for strong versus weak storm signals. And yeah this is kind of a mess so let's take a look at why. With this little bit of snow ending Thursday we might see right along the front range and that upslope. An inch maybe a couple inches but again it'll be gone pretty quickly on Thursday. So looking all the way back to Wednesday we're going to take a look at this big ridge. We're going to go through a slide sequence of just 500 millibar maps. These maps are the height you have to go into the atmosphere to find 500 millibars which is about half sea level pressure. Where you see these lines bulge northward you have a ridge. You have extra area, high pressure there. So you have to go higher off the sea level surface of the earth to get to 500 millibars. In the red lined troughs it's like the canyon where water or river would flow between mountain ridges. You have the lowest heights and so that you usually get the storminess on the right side of these troughs. That's where everything comes together to lift the atmosphere and if you get atmosphere lifted you can get clouds, moisture and precipitation. So back on Wednesday take a look at this big ridge out west. We're going to keep an eye on it because even though things are going to kind of translate through this pattern that ridge is going to kind of hold strong. And that is what's going to give us that long period of storminess next week. So going to Thursday p.m. there's our ridge kind of bent over. You can still see in the northern branch of the jet stream a piece of that ridge still back over here. There's just this trough cutting through and it's breaking apart from the trough here that was down in the Pacific leaving this little cutoff low. So here's closed circulation. The air is going around the low counterclockwise and when you get a low cutoff from the main jet stream flow it doesn't go very fast. Let's go to Friday. Yep it hasn't moved very far at all. It's a little bit closer to California. Of course the uphill side of this trough is where you'll get your storminess. It's going to be southern California and Arizona parts of Baja and Mexico way down south. And we have a hint of this ridge still holding strong in the southern and northern branches of jet stream. And the branches of jet stream are just this. You can see one big flow coming in across the Pacific. You've got this flow down here kind of joining stuff from the South Pacific up over southern states rejoining off in the Atlantic. The northern branches up here through Canada north of the Great Lakes and across. Let's go to Saturday. Here's our ridge still holding strong up in Alaska in western Canada. There's a hint of a northern even more northern extent of the ridge. We have a bit of a ridge behind this cutoff flow. And ahead of the cutoff flow is this main central ridge in the middle of the nation. We're caught in the middle with a little bit of up. Downstream of the trough lift giving us maybe that little bit of showeriness on Saturday. Saturday night. So going into Sunday finding that little cutoff flow is translated up into the Kansas and Nebraska areas. And it's starting to kind of join in with the jet stream. But this is a weird fractured pattern. You can see our ridge is still trying to hold here in a very contorted fashion. There's a shortwave cutting into the Pacific Northwest. We have our low departing going across the southern plains. A little bit of a ridge on the southeast. And then this big ridge coming into the Pacific. And everything snaps on Monday. This is a really recent entry to my slide set. So I didn't get to draw the lines on it. But now we've reestablished a big ridge in the west with northwest flow coming down across Colorado. You've seen the earlier briefings whenever you have northwest flow. You're usually a little cooler than normal because the heights are lower in the center part of the nation. You're getting a flow from the north. So you've got cold air as your source. And little ripples coming through can kick off the snowstorm or rain showers at any time. And that's the background to why it looks so nishmashy next week with cold temperatures. And many chances of at least small shots of snow or rain. So looking back again, there's our Saturday night Sunday chance of showers. And here's the northwest flow reestablished and the cold air in place. How much snow might we get over the next 10 days? So the GFS is still not impressed even with all this activity going on. Yeah, it's about one to two inches across Lawn Mott. Maybe two to four inches right around Boulder. The northern Rockies don't get much in this, but the southern Rockies do. We have some areas down here in the San Diego Crystal Mountains. I should have practiced that before going on air here. But a foot to foot in half of snow and some snow favorite locations. Yeah, this is more of a southern track. You saw how far south that cut off low travels. And that's where the activity will be as soon as Arizona and the Mexico and southern Colorado. So simplifying it all, we're cold Thursday and the ridge moves in on Friday, Saturday and into Sunday, giving us some pretty mild conditions. A little shortwave cuts through giving us a little chance of snow on Sunday. The Northwest flow starts bringing cold air for the beginning and middle of next week. And we have nighttime temperatures dropping down to the single digits with snow possible any day, Monday night to Tuesday and Wednesday night. Before we go, let's take a look at what the snow pack looks like for Colorado. Right now we are at 114 percent normal for this point in the year. The big thick red line is the median snowfall is kind of the average road you expect through the season. October is on the far left. April is peak snow for Colorado and then things start warming up and melting. And by the time we get to the end of June, it's usually gone. So we are right here on the end of this dark blue line. And very similar to the lighter blue line, which was the water year 2019. So just last year. So very, very similar. Last year we had a lot of light season heavy snow come in that remains to be seen, whether that will reestablish itself. Looking regions and watersheds across Colorado. We are in the South Platte up here. Northeast Colorado is at 132 percent. Northwestern regions are about 120 percent above normal. And then looking down the Southwest, it's been normal even when we looked at the drought conditions. It's kind of dry down there. We're just at 100 or just below 100 percent. That's not bad. I mean, you're really close to normal. 97 percent. I don't know if your average vegetation patch on the mountainside would know the difference between 97 percent normal and 100 percent. So we're doing really well as far as snow goes. And I know skiers are in heaven. So for frequent updates and even discussion on watches and warnings and future videos, I'll be posted at the Longmont Observer at longmontobserver.org. Also a great source for local news. So stay connected to your community here. And told to like and subscribe. So if you're watching on YouTube, go down there and like and subscribe so you know when we put the next video out. So for Longmont Public Media for covering February 2022, this has been Chief Meteorologist John Insworth. Keep looking out.