Pilot weather reports, or more simply PIREPs, are critical for aviation safety. Notice below that a TBM9 reported moderate to severe turbulence at FL300 near Norfolk, Virginia as shown on the PIREP layer of the EZWxBrief progressive web app.

This PIREP for moderate to severe turbulence got the attention of the Center Weather Service Unit (CWSU) for the Washington ARTCC that issued the Center Weather Advisory (CWA) for turbulence shown below in the EZWxBrief progressive web app. Notice the CWA text “RPRTD BY TBM9.” This is an excellent example of why making pilot weather reports are so important (urgent or otherwise). It’s likely the turbulence didn’t meet National SIGMET criteria that would normally prompt the Aviation Weather Center (AWC) to issue a SIGMET, so that’s when the CWSU steps in to issue their CWA. CWAs don't need to meet specific criteria in order to be issued. That's why they are considered the "front lines" of aviation weather. They have a short fuse since they are typically valid for no more than two hours from the time they are issued (whereas a SIGMET is valid for four hours).

This area of moderate or greater turbulence did show up nicely as high values of Eddy Dissipation Rate (EDR) in the EZWxBrief progressive web app Airport Wx profile shown below. A value of 33 at FL300 is indicative of moderate to severe turbulence where severe starts at an EDR value of 36 (note that EDR is actually a value from 0 to 1.0, but EZWxBrief multiplies this by 100 to make it easier to consume). This kind of guidance is important since there’s not always a PIREP and CWA (or SIGMET) to warn you about a rough ride. It is often the case that SIGMETs and CWAs live and die by PIREPs.

Looking at the Skew-T from the HRRR at this location about 19 minutes later (16Z) shows a scenario where severe turbulence may be likely at this altitude. Unstable air at 300 mb right below the tropopause along with some moderate speed shear.

So keep those PIREPs coming...even if they are boring. Boring PIREPs are the key for forecasters to draw the correct boundaries. Moreover, you may be in smooth air clipping along happily at 10,000 feet when just two thousand feet above or below you might be rough air. Your boring PIREP of smooth air could help that pilot who is looking for those boring smooth conditions.
Most pilots are weatherwise, but some are otherwise™
Dr. Scott Dennstaedt
Weather Systems Engineer
Founder, EZWxBrief™
CFI & former NWS meteorologist
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