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Do You Know When A SPECI Will Be Issued For Rapidly Changing Weather?

Did you know a SPECI weather report can be issued for rapidly improving OR deteriorating conditions? A SPECI caused this airplane to perform a missed-approach. Here's what you should know before your next flight...

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METARs Are Routine, SPECIs Are Not

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.

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. Fortunately, METARs and SPECIs are coded using the same format.

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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:

FAA

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 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.


Boldmethod

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 catch your attention. Due to the nature of rapidly changing conditions, you should take extra time to analyze weather trends at your destination and nearby airports. It's one of the first indicators leading to diversion planning if conditions are deteriorating rapidly.

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.

Swayne Martin

Swayne is an editor at Boldmethod, certified flight instructor, and an Embraer 145 First Officer for a regional airline. He graduated as an aviation major from the University of North Dakota in 2018, holds a PIC Type Rating for Cessna Citation Jets (CE-525), and is a former pilot for Mokulele Airlines. He's the author of articles, quizzes and lists on Boldmethod every week. You can reach Swayne at swayne@boldmethod.com, and follow his flying adventures on his YouTube Channel.

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