An Aviation Selected Special Weather Report (SPECI) is an unscheduled report taken when there is a significant change in the weather during the period between the hourly reports. SPECIs contain all data elements found in a METAR, plus additional plain language information which elaborates on data in the body of the report.
To make things consistent, METARs and SPECIs are coded using the same format.
How Are SPECIs Different Than METARs?
Aviation Routine Weather Reports (METARs) and Aviation Selected Special Weather Reports (SPECIs) report the current weather conditions at an airport. METARs are reported once per hour, and are the most common type of observation. Each METAR includes the airport identifier, time of observation, wind, visibility, runway visual range, present weather phenomena, sky conditions, temperature, dew point, and altimeter setting. Click here to learn how to read METARs, SPECIs, and more.
SPECI Issuance Criteria
There are 12 categories for why a SPECI may be issued, with several sub-groups. You don't necessarily need to know each by heart, but understanding the general trend is important. SPECIs can indicate improving or degrading weather trends, so take a look at nearby airports or previous reports to compare the changes.
Here's a table from the FAA explaining exactly when a SPECI will be issued, instead of a regularly scheduled METAR:
Whenever SPECI criteria are met at the time of the routine METAR, a METAR is issued.
Report: SPECI Report Causes Missed Approach
A SPECI can also be a good way to tell that a towered airport is now operating under IFR. You might've noticed in the chart above that there are thresholds for SPECIs being issued for weather crossing the 1,000-foot ceiling threshold or 3 miles of visibility.
The following NASA ASRS Report was filed by an air traffic controller working with an IFR aircraft approaching the Chicago Executive Airport:
The Chicago Executive Airport (PWK) has an instrument approach to only one runway (RWY 16). So, when the winds are favoring runway 34, aircraft are asked to cancel their IFR prior to circling because of our proximity to ORD airport... That makes it much easier for us to fit multiple IFR aircraft into the airport without a need to protect the circling area around the airport. When I began working the Local Control position, winds were gusting out of the northeast at over 20 knots and aircraft were canceling IFR and circling to runway 34 with a ceiling of BKN011. (MVFR conditions)
A SPECI was then issued indicating 01014G22KT 10SM BKN009. A pilot approaching PWK was instructed to circle west for left traffic for runway 34. Standard IFR separation was about to be lost between this airplane and another preceding aircraft on the approach, and the second aircraft requested to cancel IFR. Due to the airport now operating under IFR, I couldn't allow the aircraft to fly VFR and enter the protected circling area for the preceding aircraft. Initially, there was some confusion about whether the first aircraft was operating under VFR or IFR. I issued missed approach instructions to the second aircraft due to the degrading conditions and loss of separation.
A SPECI Was Issued At Your Destination. What Now?
Seeing a SPECI could be a sign of improving conditions at your destination or a sign that you're about to fly into challenging weather.
Regardless, anytime you see "SPECI," it should grab your attention. Due to the nature of rapidly changing conditions, you should spend time analyzing weather trends at your destination and nearby airports. It's one of the first indications that you may need to divert.
How often have you noticed SPECI reports during your cross-country flights? Tell us about your experience in the comments below.
Want to learn more about METARs, SPECIs, and other weather reports and forecasts? Sign up for our Aviation Weather online course here.
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