# How long is a winds and temperatures aloft forecast valid for?

How long is a winds and temperatures aloft forecast valid for and how often is it published?

Also, is there anywhere which says the times of publication and valid through times for all of the aviation weather charts? My google fu isn't helping.

Advisory circular 00-45 "Aviation Weather Services" documents the winds and temperature aloft (FB) product on page 7-39. Table 7-11 lists the standard forecast periods for these products.

From this table you can see that the 6-hour forecasts are usable from the time they are issued until 3 hours after the valid time. The 12 hour forecasts are usable from -3 to +6 hours of the valid time and 24 hour forecasts are usable from -6 to +6 hours of the valid time. The products are issued 4 times daily.

While these are standard times, you should consult the specific information available in the product header that has this information. For example:

DATA BASED ON 010000Z
VALID 010600Z FOR USE 0500-0900Z. TEMPS NEG ABV 24000
FT 3000 6000 9000 12000 18000 24000 30000 34000 39000
MKC 9900 1709+06 2018+00 2130-06 2242-18 2361-30 247242 258848 550252


This says the product is valid at 06Z and for use from 05Z to 09Z and the data is based upon the 00Z forecast model run.

According to NOAA: (https://www.aviationweather.gov/products/nws/info)

Sample winds aloft text message:

DATA BASED ON 010000Z VALID 010600Z FOR USE 0500-0900Z. TEMPS NEG ABV 24000 FT 3000 6000 9000 12000 18000 24000 30000 34000 39000 MKC 2426 2726-09 2826-14 2930-21 2744-32 2751-41 275550 276050 276547

The portion that indicates valid times:

VALID 010600Z FOR USE 0500-0900Z.

The valid time of the forecast is the first day of the month at 0600 UTC. The forecast winds and temperature are to be used between 0500 and 0900 UTC.

The frequency of publication is described explicitly here: (https://en.wikipedia.org/wiki/Winds_aloft)

This forecast is now made four times a day based on 0000Z, 0600Z, 1200Z, and 1800Z

Every forecast has a valid time, and in fact valid times are different for the same type of forecast in different locales , for example TAFs are valid for either 4 or 6 hours.

My answer, therefore, is that the valid time for ANY forecast is whatever the forecast itself says.

There is also an UPPER WIND AND TEMPERATURE product issued by WAFC London. These are issued in 3-hr increments and valid -/+ 1.5 hrs. So a 1200Z chart would be valid 1030Z - 1330Z. In raw form they usually have a product code associated with them. Example: PWBE85.