Expect a 35–45 kt southerly low-level jet near 1,500–2,000 ft AGL 08–14Z along the I-35 corridor from ICT to DSM, with pockets of light rime icing in stratocu where tops sit near -4 to -9 C. If you’ve got early departures or training approaches, double-check TAF trends, G-AIRMETs, and HRRR/RAP updates and consider altitudes that keep you either below the shear layer or above the cloud tops; I’ll post a quick update if the guidance shifts closer to 06Z.
approaches, double-check TAF trends, G-AIRMETs, and HRRR/RAP updates and consider altitudes that keep you either below the shear layer or I had a 12Z training hop out of OJC with a 40 kt LLJ at 1,800’ and tops around -6 C; we briefed an immediate climb to 5k to get above the shear, but kept a plan to level at 2k if the tops looked chunky to avoid picking up rime — HRRR nailed the timing but was off by about 500 ft on the core height, ugh. Small caveat: if you’re non-FIKI along ICT–DSM, a 30–45 min delay after 13Z has saved me twice as mixing eased the LLWS and the stratocu thinned.
I’ve run into this too — one small tweak that paid off was writing the expected outcome before touching the settings.
Quick example: had a 09Z departure out of TOP with a 40 kt LLJ around 1,800 AGL — stayed under it near 1,200 for about 10 miles, then climbed through the stratocu fast and only picked up a light rime trace at about -6°C for a minute. If you’re in that ICT–DSM I‑35 band “08–14Z,” sanity‑check a RAP/HRRR skew‑T via https://rucsoundings.noaa.gov; tops ran 500–800 ft higher than TAFs hinted, which drives me nuts. One caveat: right after sunrise the mixing knocked the shear down fast, so a 30–45 min delay made it a non‑issue for us.
On predawn hops I’ve had smoother results turning pitot heat on early and climbing through the shear at Vy+5 to minimize time in the cold band — then leveling above the layer if tops are shallow. If bases sit too low for that, I’ll stay under the push for a few miles and time the climb using aviationweather.gov/sounding.
But i’ve had good luck on predawn training approaches carrying Vref+5 on final and avoiding a downwind that drags you back into the inversion; if I see any rime, I’ll level in the warmest slice and let it shed before continuing, terrain/airspace permitting. Quick ‘tops check’ with https://rucsoundings.noaa.gov usually matches RAP, and if winds aloft back more than expected I’ll just stay underneath and keep it short, @l_baxter900.