• Graphical cloud tops (CLD TOPS)  • Graphical lightning strikes (LTNG)  • Graphical storm cell movement (CELL MOV)  • NEXRAD radar coverage (information displayed with  the NEXRAD data)  • SIGMETs/AIRMETs (SIG/AIR)  • Surface analysis to include city forecasts (SFC)  • County warnings (COUNTY)  • Freezing levels (FRZ LVL)  • Hurricane track (CYCLONE)  • Temporary flight restrictions (TFR)  • Request to deviate off course by stating the number  of miles and the direction of the requested deviation.  • Request a new route to avoid the affected area.  • Request a change of altitude.  • Request radar vectors around the affected areas.  Pilots must be familiar with any EFD or MFD used and the  data link weather products available on the display.  The information displayed using a data link weather link is  near real time but should not be thought of as instantaneous,  up-to-date information. Each type of weather display is  stamped with the age information on the MFD. The time is  referenced from Zulu when the information was assembled at  the ground station. The age should not be assumed to be the  time when the FIS received the information from the data link.  The controller’s primary function is to provide safe separation  between aircraft. Any additional service, such as weather  avoidance assistance, can only be provided to the extent  that it does not detract from the primary function. It’s also  worth noting that the separation workload is generally greater  than normal when weather disrupts the usual flow of traffic.  ATC radar limitations and frequency congestion may also  be a factor in limiting the controller’s capability to provide  additional service.  Two types of weather are displayed on the screen: “current”  weather and forecast data. Current information is displayed  by an age while the forecast data has a data stamp in the form  of “__ / __ __ : __.”  [Figure 13-16]  The NEXRAD system is comprised of a series of 159 Weather  Surveillance Radar–1988 Doppler (WSR-88D) sites situated  throughout the United States, as well as selected overseas  sites. The NEXRAD system is a joint venture between the  United States Department of Commerce (DOC), the United  States DOD, as well as the United States Department of  Transportation (DOT). The individual agencies that have  control over the system are the NWS, Air Force Weather  Agency (AFWA) and the FAA.  [Figure 13-17]  Many aircraft manufacturers now include data link weather  services with new electronic flight display (EFD) systems.  EFDs give a pilot access to many of the data link weather  services available.  Products available to a pilot on the display pictured in  Figure 13-15  are listed as follows. The letters in parentheses  indicate the soft key to press in order to access the data.  NEXRAD data for up to a 2,000 mile range can be displayed.  It is important to realize that the radar image is not real time  and can be up to 5 minutes old. The NTSB has reported on 2  fatal accidents where in-cockpit NEXRAD mosaic imagery  was available to pilots operating near quickly-developing and  fast-moving convective weather. In one of these accidents,  the images were from 6 to 8 minutes old. In some cases,  NEXRAD data can age significantly by the time the mosaic  image is created. In some extreme latency cases, the actual  • Graphical NEXRAD data (NEXRAD)  • Graphical METAR data (METAR)  • Textual METAR data  • Textual terminal aerodrome forecasts (TAF)  • City forecast data  • Graphical wind data (WIND)  • Graphical echo tops (ECHO T,,,OPS)  13-18  Weather Products Age and Expiration  The Next Generation Weather Radar System  (NEXRAD)  Electronic Flight Displays (EFD) /Multi- Function Display (MFD) Weather  Weather Avoidance Assistance  any associated with lesser rates of precipitation. Turbulence  should be expected to occur near convective activity, even  in clear air. Thunderstorms are a form of convective activity  that imply severe or greater turbulence. Operation within  20 miles of thunderstorms should be approached with great  caution, as the severity of turbulence can be much greater than  the precipitation intensity might indicate.  To the extent possible, controllers will issue pertinent  information on weather and assist pilots in avoiding such  areas when requested. Pilots should respond to a weather  advisory by either acknowledging the advisory or by  acknowledging the advisory and requesting an alternative  course of action as follows: 