Effective April 13, 2017, the experimental Graphical Forecasts for Aviation (GFA) produced by the NWS Aviation Weather Center (AWC) will transition to operational status. As you may have heard, the GFA was created in response to a formal request by the FAA to discontinue production of the textual Area Forecasts (FA). According to the NWS headquarters in Silver Spring, Maryland, “the requirements for the underlying meteorological information in the FA have not changed. The FAA recognizes that, given modern advances within the NWS, the legacy text FA is no longer the best source of en route flight planning weather information.”
The new graphical forecasts are designed to provide meteorological information equivalent to the textual FA. The GFA product includes observations and forecasts for the continental United States that provide data critical for aviation safety. The data is overlaid on high-resolution base maps that you can test drive here. This means that all of the forecasts will terminate at the U.S. border. FAs for Hawaii, Alaska, the Caribbean, and the Gulf of Mexico will not be affected at this time.
For the time being, the legacy FA will continue to be generated in parallel with the GFA. The GFA is automated whereas the legacy FA is issued by forecasters at the AWC. At some point in the future, forecasters at the AWC will discontinue issuing this textual forecast. And don't be surprised if the two forecasts contradict one another – let's look at an example:
Below is the GFA valid at 23Z (issued at 2102Z) for cloud coverage along with tops and bases for the Northeast. Notice that it forecasts just high cirrus over a majority of Maine.
The GFA cloud forecast shows cloud coverage (color contours) as well as bases and tops.
However, the legacy FA for this area shown below suggests a totally different forecast. This area forecast was amended by the FA forecaster for the eastern region at 1935Z. This forecast (highlighted below) suggests that after 21Z NW Maine is expected to have overcast clouds with bases at 2,000 – 3000 feet MSL. And NERN Maine is expected to have overcast cloud bases of 1,500 feet MSL. The forecaster also issued an AIRMET for IFR conditions covering most of the northeastern U.S.
000 FAUS41 KKCI 141935 AAA FA1W BOSC FA 141935 AMD SYNOPSIS AND VFR CLDS/WX SYNOPSIS VALID UNTIL 151200 CLDS/WX VALID UNTIL 150600...OTLK VALID 150600-151200 ME NH VT MA RI CT NY LO NJ PA OH LE WV MD DC DE VA AND CSTL WTRS . SEE AIRMET SIERRA FOR IFR CONDS AND MTN OBSCN. TS IMPLY SEV OR GTR TURB SEV ICE LLWS AND IFR CONDS. NON MSL HGTS DENOTED BY AGL OR CIG. . SYNOPSIS...SEE MIA FA FOR SYNOPSIS. . ME NH VT NW ME/NRN-SW NH/VT...OVC020-030 TOP FL250. VIS 3SM -SN BR. 21Z OVC020-030. VIS 3SM -SN BLSN. WND N 20G30KT. OTLK...IFR CIG SN BLSN WND. NERN ME...OVC030 TOP FL250. VIS 3-5SM -SN. 21Z OVC015. VIS 3SM -SN BR. 03Z OVC015. VIS 3SM -SN BLSN. WND NELY G25KT. OTLK...IFR CIG SN BLSN WND.
Notice the Synopsis section simply says “SEE MIA FA FOR SYNOPSIS.” Most pilots were probably not taught that the FA has a 3,000 character limit. So, with a raging Nor'easter occurring in the Northeast, they didn't have enough characters available for the Boston FA to provide a complete synopsis. In that case, the forecaster opted to place the Boston synopsis in the Miami FA.
For the potential of clouds in Maine, the legacy FA proved to be much more accurate than the new GFA. Most of Maine was experiencing IFR conditions as denoted by AIRMET Sierra shown here.
At this point in time, the AWC is not providing public access to some of the underlying data you may see on the webpage mentioned above. We are busy at ForeFlight trying to determine how to best incorporate these forecasts from the GFA once they become available. So stay tuned.