One of the most valuable tools for planning a crosscountry or checking to see weather conditions are Pilot Reports or PIREP. The importance of PIREP’s is that their information doesn’t come from meteorologists or weather observers, the information comes from the pilots. PIREP’s are useful for checking actual conditions versus forecast conditions, or checking to see the severity of icing or turbulence. There are two types of PIREP’s: Urgent (UUA) and Routine (UA). The criteria for urgent PIREP’s are as follows:

• Tornado, Waterspout, or a Funnel Cloud
• Hail
• Severe or Extreme Turbulence
• Severe Icing
• Low Level Wind Shear with 10 knots or greater in airspeed changes
• Volcanic Ash
• Any other potentially hazardous phenomenon.

The format for PIREP’s is pretty straight forward. There are five items in any PIREP that are neccessary :

• Urgent (UUA) or Routine (UA)
• /OV  - Location in relation to NAVAID, airport, or latitude and longitude.
• /TM – Time (reported in Zulu)
• /FL – Flight Level or altitude (MSL)
• /TP – Aircraft Type

After the necessary information has been collected, any of the following information can be reported:

• /SK – Sky Cover
• /WX – Weather conditions or flight visiblity
• /IC – Icing
• /TA – Outside Air Temperature (in Celsius)
• /TB – Turbulence
• /WV – Wind Velocity (Direction is also reported)
• /RM – Remarks

Below is an example of a PIREP:

BFL UA /OV EHF090015 /TM 0028 /FL085 /TP COL4 /SK OVC-TOP040 /WV 30024KT /TB NEG /RM WV ESTIMATED

To read this, you just start reading left to right. This PIREP was closest to the airport BFL (Meadows Field Airport) and is a routine report (UA). The exact location of the PIREP was 15 miles off of the 090° radial of the EHF VOR (EHF 090015). Time was 0028 Zulu, and altitude was 8,500 feet. The airplane was a Cessna 400 (COL4). The PIREP reports that the sky condition (/SK) was overcast with tops of 4,000 feet MSL (OVC-TOP040). Wind was 300° at 24 knots (WV 30024KT). No turbulence is present (/TB NEG). Remarks (/RM), wind velocity/direction estimated.

Here is another example of a PIREP:

MAE UA /OV PXN /TM 0604 /FL140 /TP E120 /TA M05 /IC LGT-MOD RIME /RM 30 NM RADIUS

This PIREP reads as follows: Closest airport is MAE (Madera Municipal Airport), over the PXN VOR at 0604 Zulu. Aircraft was an Embraer 120 flying at 14,000 feet. The outside temperature is negative 5°C. Light to moderate rime icing is occuring. Remarks, conditions existing in 30 nautical mile radius.

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Resources: For more detailed information, check out the FAA published book: Aviation Weather Services. This book contains all the information about every weather service available for pilots. This book is a valuable resource when it comes to studying for checkrides or trying to decipher the more uncommon weather products. Click on the book below to find out more.