Significant Changes to Aviation Portion of Area Forecast Discussion (AFD)

Effective April 26th, 2010:

 

Guidelines for the Enhanced Aviation AFD


This format will be used all days and not just the days of Enhanced Aviation Services.

This format change includes features requested by our users.

I. Main Body of Text, Synopsis
  

     A. Keep relatively short and concise. Focus on aviation weather

          impacts general to the area. Avoid technical jargon, things like

          “isentropic lift”, “850mb frontogenesis”, discussions of “elevated

           convection”, ”Theta-E Advection”. Use language that a weather savy

           aviation-related decision maker would understand, dispatchers,

           TMU/Tracon staff, GA pilots. The target audience is not scientists.

           The Public AFD is the place to flex your scientific muscles.

     B. Updated with the 00Z, 06Z, 09, 12Z TAF issuance. Update other times

          as necessary if it becomes unrepresentative of anticipated conditions.


II. ORD-centric section

       A. Terminal specific breakout. Details of wx impacts on ORD. Deterministic in nature.

       B. Confidence statement. Offer alternative possibilities especially if there is low

            confidence situations, but would have high impact if it occurs. This portion should

            be more probabilistic in nature. However, this is not for things like “there is a 30%

            chance of 2500 ft ceilings” or a “60% chance of visibility reduced to 2 sm”. Rather  a

            statement of whether your confidence in the forecast situation is high, medium or low.

       C. Updated with each mandatory 2 hour TAF issuance (or 3-hour issuance on weekends).

            Update other times as necessary with amendments.

III. MDW-centric section

         A. Terminal specific breakout. Details of wx impacts on MDW. Deterministic in nature.

         B. Confidence statement. Offer alternative possibilities especially if there is low

              confidence situations, but would have high impact if it occurs. This portion should

              be more probabilistic in nature. However, this is not for things like “there is a 30%

              chance of 2500 ft ceilings” or a “60% chance of visibility reduced to 2 sm”. Rather a

              statement of whether your confidence in the forecast situation is high, medium or low.

         C. Updated with each mandatory 2 hour TAF issuance (or 3-hour issuance on weekends).

              Update other times as necessary with amendments.

IV. Extended Outlook for Days 2 through 5

          A. Very Brief

          B. Updated with the 18Z TAF issuance AFD, but may be updated as necessary if

               anticipated conditions become unrepresentative of current thinking.

          C. General, but more tailored to the ORD/MDW TAFs.



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