After 20 years of living in Colorado, you know that March weather in the Rockies means anything from blizzards to warm, spring-like days. Unfortunately the weather is closer to the first extreme for your planned trip tonight, a 1:30 flight from your home in Denver (BJC) to Provo, Utah (PVU), to visit your son in college. Your Cessna 421 is a capable airplane, with two turbocharged engines, pressurization, full deice boots, and a glass cockpit. Looks like you might need all that gear today.
You are fully IFR qualified and proficient, and the plan is for an IFR flight today. Departure is scheduled for 2330Z, which means you’ll be arriving just before sunset in the Salt Lake City area. Read the weather forecast below, then tell us if you would go or cancel. Remember – there’s no right or wrong answer here. The goal is to practice your decision-making skills and share your thinking with other pilots.
A look at the Maps page in ForeFlight shows a rainbow of colors, with rain, snow and mixed precipitation north of Denver, another patch of rain over western Colorado, and more rain to the north of your destination.
The surface analysis shows a low parked over Colorado and another one in eastern Nevada.
The satellite image shows solid clouds all along your route of flight, with the thickest parts in the middle. It does look like the clouds break up as you get towards Salt Lake City.
So far you have an idea of current conditions. What about the future? Unfortunately, the forecast doesn’t show much of an improvement, as a look at the first prog chart shows:
The next one shows the low moving slowly off to the northeast, but leaving plenty of rain and snow behind:
The biggest concern today is proabably in-flight icing. While your 421 is approved for flight into known icing (FIKI), no airplane can linger in serious icing for long. The easiest way to evaluate the threat is to use ForeFlight’s icing layers. It looks like you’ll be mostly-ice free for takeoff and landing, since the 8,000 ft. icing chart is mostly clear:
By 14,000 feet there is definitely some ice to tangle with, although mostly light.
Same story at 20,000 feet, with icing in the middle of your flight. Again, it’s mostly light:
The good news is that you can get on top by 22,000 feet today. That’s definitely doable in your 421, which you regularly fly in the low to mid-twenties.
Winter and mountains often mean turbulence too, so a quick look at the turbulence forecast is in order. Those charts show the expected bumps down low, especially over the Front Range, but they persist up to 18,000 feet.
How about once you’re out of the ice (hopefully) at 22,000 feet – is it any better? A little:
So far you’ve looked at forecast products; now it’s time to see what pilots are saying. There are plenty of icing PIREPs out there, including this one between 13,000 and 9,000 feet near your destination.
Here’s another one that shows light rime and moderate turbulence at 13,000 feet near Denver.
Another one near Denver shows light icing from 14,000 to 16,000.
South of your route there’s a report of moderate ice at 15,000:
The scariest PIREP is well south of your route, but shows severe icing at 13,000 feet.
Given all the weather and the potential for icing, a look at the skew-T diagrams is a good idea today. First up is Denver, which shows a bit of a temperature inversion and seemingly endless clouds. The winds are steady out of the west:
And here’s the diagram for Salt Lake City:
Now it’s down to the METARs and TAFs. Finally there’s some good news. Conditions at your departure are good VFR with light winds, and it’s forecast to stay that way for a while:
Your destination is also reporting good VFR weather and calm winds, although the forecast isn’t quite so good:
En route weather is much more varied. 20V, closer to Denver, is windy but VFR, while 4V0 and VEL are IFR:
It’s time to decide whether you’re going flying today or not. It’s certainly an IFR day, with rain, snow, icing and probably some turbulence – not an easy flight. On the other hand, you are an experienced IFR pilot with a high performance airplane and it looks like you can get on top of the ice today.
Add a comment below and tell us what you would do. Then tell us why you reached that conclusion.