Interested in DIFAX maps and charts Below are frequently asked questions and descriptions of the specific DIFAX maps and charts offered. If you have a question that we didn't answer, let us know!

Q. What are the descriptions of the available DIFAX maps and charts

• U.S. Radar Composite
  
• U.S. Weather Depictions
  

• Significant Weather Forecasts (PROGS)
  
• Significant Weather Forecasts, Flight Level 250 to 600
  

• Constant Pressure Analyses
  
• Winds Aloft
  
• RAFS/NGM Forecast
  
• AVN/MRF (Spectral) Forecasts
  
• LFM Forecasts
  
• Wind and Temperature Progs
  

• Current Surface Weather Analyses
  
• Forecast Weather
  
• Thickness
  

• Temperature-Related Charts-U.S.
  
• Sunshine/Air Stagnation
  
• Precipitation and Snow
  
• Crop Moisture-U.S.
  
• Extended-Long Range Forecasts
  
• Ocean and Marine
  

Radar/Weather Depictions

• U.S. Radar Composite
  Chart depicts shaded areas of precipitation over the continental U.S. Precipitation cells and expected movement is shown. Weather Watch areas. Administrative messages from National Meteorlogical Center.
       Coverage Area: Continental U.S.
• U.S. Weather Depiction
  Useful for flight planning. Shows sky cover, surface fronts, ceilings, visibility. Indicates IFR, MVFR and VFR areas.
       Update time(s): 0209z, 0517z, 0815z, 1123z, 1405z,1720z, 2017z, 2316z
       Coverage Area: Continental U.S. and Southern Canada
  

Significant Weather Depictions

• 12 & 24-hour forecasts
  Weather systems, clouds, precipitation, turbulence, flight rules. Four panel chart. Upper two panels show 12 & 24-Hour prognosis of IFR and severe weather. Also shows freezing levels, ceilings, visibility, and any turbulence. Lower two panels depict 12 & 24-Hour areas of high and low pressure, frontal systems, and shaded areas of expected precipitation.
       Update time(s):0007z, 0551z, 1006z, 1739z
       Coverage Area: Continental U.S., Southern Canada
  
• 36 & 48-hour forecasts
  Weather systems, clouds, precipitation.Two panel chart shows high and low pressure centers, frontal systems, areas of expected precipitation and cloud cover over the U.S. and southern Canada. Both panels include a prognostic discussion of chart prepared by the National Meteorological Center.
       Update time(s): 0720z, 1914z
       Coverage Area: Continental U.S., Southern Canada
  
• Severe weather outlook
  Likelihood of severe thunderstorms over the next 48 hours. Two panel chart depicts areas of potentially severe thunderstorms over the Continental U.S. in the next 48-hours.
       Update time(s): 1030z
       Coverage Area: Continental U.S.
  
• Thunderstorm & severe thunderstorm probabilities
  Likelihood of severe thunderstorms over the next 48 hours. Two panel chart depicts areas of potentially severe thunderstorms over the Continental U.S. in the next 48-hours.
       Update time(s): 1303z
       Coverage Area: Continental U.S.
  
• Snow cover & 6-hour snowfall (available 9/17-4/15)
  Chart depicts total snow depth in inches and the 6 hour snowfall
       Update time(s): 1303z
       Coverage Area: Continental U.S.
  
• Thunderstorm & severe thunderstorm probabilities (MOS)
  Chart depicts 24-hour probabilities of thunderstorms and severe thundertorms over the continental U.S. Also shows chart valid times.
       Update time(s): 0418z
       Coverage Area: Continental U.S.
  
• Forecast surface wind, cloud cover, and flight rules (MOS)
  Four panel chart shows forecast 12-hr, 18-hr, 24-hr and 30-hr surface winds, cloud cover and visibility.
       Update time(s):0415z, 1553z
       Coverage Area: Continental U.S.
  

Significant Weather Forecasts

• Clouds, weather systems, precipitation, turbulence
  Chart shows Flight Level 25,000-60,000 ft. cloud cover; wind speed and direction; frontal systems; and any significant weather; including turbulence, hail and icing. Altitude is shown in hundreds of feet.
       Update time(s): 0114z, 0857z, 1315z, 2028z
       Coverage Area: North & Central America and Surrounding Areas
  
• Clouds, weather systems, precipitation, turbulence
  Chart shows Flight Level 25,000-60,000 ft. cloud cover; wind speed and direction; frontal systems; and any significant weather; including turbulence, hail and icing. Altitude is shown in hundreds of feet.
       Update time(s): 0154z, 0851z, 1328z, 1955z
       Coverage Area: Eastern Asia and the Pacific
  
• Clouds, weather systems, precipitation, turbulence
  Chart shows Flight Level 25,000-60,000 ft. cloud cover; wind speed and direction; frontal systems; and any significant weather; including turbulence, hail and icing. Altitude is shown in hundreds of feet.
       Update time(s): 0854z, 1333z, 2044z
       Coverage Area: Europe, Africa, Atlantic
  
• Clouds, weather systems, precipitation, turbulence
  Chart shows Flight Level 25,000-60,000 ft. cloud cover; wind speed and direction; frontal systems; and any significant weather; including turbulence, hail and icing. Altitude is shown in hundreds of feet.
       Update time(s): 0119z, 0712z, 1520z, 1917z
       Coverage Area: North America, Europe, Africa, Atlantic
  
• Forecast clouds, weather systems, precipitation, turbulence
  Chart shows Flight Level 25,000-60,000 ft. cloud cover; wind speed and direction; frontal systems; and any significant weather; including turbulence, hail and icing. Altitude is shown in hundreds of feet.
       Update time(s): 0119z, 1320z, 6z, 18z
       Coverage Area: North America, Europe, Africa, Atlantic
  
• Clouds, weather systems, turbulence
  Chart shows Flight Level 25,000-60,000 ft. cloud cover; wind speed and direction; frontal systems; and any significant weather; including turbulence, hail and icing. Altitude is shown in hundreds of feet.
       Update time(s):0141z, 1352z, 1939z
       Coverage Area: Alaska and the Pacific
  
• Significant Weather Forecast Flight Level 0 to 400 millibar
  Hand analyzed chart shows Flight Level surface-40,000 ft. cloud cover; wind speed and direction; frontal systems; and any significant weather; including turbulence, hail and icing. Altitude is shown in hundreds of feet.
       Update time(s): 0203z, 1423z
       Coverage Area: North Atlantic & Europe
  

Upper Air Maps and Charts

• 850 millibar analysis heights and temperatures with winds
  Chart shows centers of high and low heights, wind speed and direction, temperatures for specific locations, 850 mb heights and tendencies.
       Update time(s): 0243z, 1433z
       Coverage Area: North America
  
• 700 millibar analysis heights and temperatures with winds
  Chart shows centers of high and low heights, wind speed and direction, temperatures for specific locations, 700 mb heights and tendencies.
       Update time(s): 0248z, 1436z
       Coverage Area: North America
  
• 500 millibar analysis heights and temperatures with winds
  Chart shows centers of high and low heights, wind speed and direction, temperatures for specific locations, 500 mb heights and tendencies.
       Update time(s): 0251z, 1439z
       Coverage Area: North America
  
• 500 millibar analysis
  Chart shows the height of the 500 mb surface and temperatures at 500 mb over the Northern Hemisphere.
       Update time(s): 0603z, 1840z
       Coverage Area: Northern Hemisphere
  
• 500 millibar analysis height changes for North America
  Chart shows forecast 500 mb height changes.
       Update time(s): 0225z, 1420z
       Coverage Area: North America
• 300 millibar height analysis
  Chart shows the height of the 300 mb surface and isotachs of wind speed at 300mb. Shaded areas indicate wind speeds above 70 knots.
       Update time(s): 1847z
       Coverage Area: Northern Hemisphere
  
• 300 millibar analysis heights and temperatures with winds
  Chart shows temperature, wind speed and direction, centers of high and low heights, 300mb heights and tendencies. Shaded areas indicate wind speeds above 70 knots.
       Update time(s): 0311z, 1443z
       Coverage Area: Continental U.S. and Canada
  
• 250 millibar analysis heights and temperatures with winds
  Chart shows temperature, wind speed and direction, centers of high and low heights, 250mb heights and tendencies. Shaded areas indicate wind speeds above 70 knots.
       Update time(s): 0235z, 1453z
       Coverage Area: Continental U.S. and Canada
  
• 250 millibar analysis heights, winds, and PIREPS for the Pacific
  Chart shows 250 mb that includes wind and temperature data from Aircraft, satellite and radiosonde. Also PIREPS reports listing any turbulence, icing, cloud cover, etc., over 55N-20S, 40W-110W area.
       Update time(s): 0617z, 1852z
       Coverage Area: Pacific Ocean
  
• 250 millibar analysis heights, winds, and PIREPS for the Americas
  Chart shows 250 mb heights, wind speed and direction, centers of high and low pressure, and PIREPS reports listing any turbulence, icing, cloud cover, etc., over an area from 50N-20S, 40W-110W area.
       Update time(s): 0621z, 2052z
       Coverage Area: U.S. & Central America
  
• 200 millibar analysis heights, winds, and Pibals for U.S./Canada
  Chart shows 200 mb heights, wind speed and direction, temperatures, and height changes over the past 12 hours. The shaded areas indicate winds over 70 knots.
       Update time(s): 0353z, 1447z
       Coverage Area: Continental U.S. & Canada
  
• 200 millibar analysis heights, winds, and Pibals for Americas/Atlantic
  Chart shows 200 mb streamlines and isotachs over 50N-20S, 10E-120W area.
       Update time(s): 1034z, 1633z
       Coverage Area: 50N-20S, 10E-120W
  

Winds Aloft

• Trajectory Forecasts (prog)
  Four panel chart shows 24 hr. forecast surface dew point trajectories, 850 mb temperature trajectories, 700 mb dew point trajectories and 12 hr. 700 mb net vertical displacement/K index.
       Update time(s): 0420z
       Coverage Area: Continental U.S.
  
• Observed winds aloft
  Four panel chart shows observed winds aloft for second standard level above surface at 10,000ft, 14,000ft, 24,000ft and 34,000ft. Upper levels also show temperature observations.
       Update time(s): 0222z, 1414z
       Coverage Area: Continental U.S.
  
• Forecast winds aloft
  Eight panel chart shows LFM 12-hour forecast winds aloft. Also shows temperatures at 6,000ft, 9,000ft, 12,000ft, 18,000ft, 24,000 ft, 30,000ft, 34,000ft, and 39,000ft.
       Update time(s): 0336z, 1541z
       Coverage Area: Continental U.S.
  
• Low level circulation and mixing ratio U.S. and Central America
  Chart shows lower mean circulation in the 1000-600 mb layer with mean mixing ratio.
       Update time(s): 0348z, 2233z
       Coverage Area: U. S. and Central America
  

RAFS/NGM Forecast

• 850 millibar heights and temperatures
  Four panel chart shows 12-hr, 24-hr, 36-hr and 48-hr forecast 850 mb heights, centers of high and low heights and temperatures over North America.
       Update time(s): 0608z, 1818z
       Coverage Area: North America
  
• 12-hour forecast
  Boundary layer winds and relative humidity. Chart shows forecast wind speed and direction and relative humidity values over the Continental U.S.
       Update time(s): 0547z, 1812z
       Coverage Area: Continental U.S.
  
• 24-hour forecast
  Boundary layer winds and relative humidity. Same as Chart above, except forecast period.
       Update time(s): 0614z, 1824z
       Coverage Area: Continental U.S.
  
• 36-hour forecast
  Boundary layer winds and relative humidity. Same as Chart above, except forecast period.
       Update time(s): 0627z, 1834z
       Coverage Area: Continental U.S.
  
• 48-hour forecast
  Boundary layer winds and relative humidity. Same as Chart above, except forecast period.
       Update time(s): 0630z, 1837z
       Coverage Area: Continental U.S.
  
• 0 to 36 -hour Lifted Index
  4-Layer Lifted Index. Four panel chart shows current and NGM forecast 12-hr, 24-hr and 36-hr maximum/minimum lifted indexes.
       Update time(s): 0526Z, 1733Z
       Coverage Area: North America
  
• Initial 500 millibar heights/vorticity, 700 millibar heights/mean humidity, pressure/thickness, 850 millibar heights/temperature
  Four panel chart. First panel shows forecast 500mb heights/vorticity locations. Second panel shows forecast 1000-500mb thicknesses and surface pressure patterns. Third panel shows 700mb heights and relative humidity. Fourth panel shows 850 mb initial conditions.
       Update time(s): 0443z, 1647z
       Coverage Area: North America
  
• 12-hour 500 millibar heights/vorticity, 700 millibar heights/mean humidity, pressure/thickness, precipitation/vertical velocity
  NGM (Nested Grid Model) Forecast Model. The top left panel show the heights and vorticity at 500 mb. The top right panel shows the MSL pressure and 1000-500 mb thickness. The lower left panel shows the 700 mb height and relative humidity. The lower right panel shows the total precipitation and 700 mb vertical velocity.
       Update time(s): 0450z, 1700z
       Coverage Area: North America
  
• 24-hour 500 millibar heights/vorticity, 700 millibar heights/mean humidity, pressure/thickness, precipitation/vertical velocity
  NGM (Nested Grid Model) Forecast Model. The top left panel show the heights and vorticity at 500 mb. The top right panel shows the MSL pressure and 1000-500 mb thickness. The lower left panel shows the 700 mb height and relative humidity. The lower right panel shows the total precipitation and 700 mb vertical velocity.
       Update time(s): 0503z, 1706z
       Coverage Area: North America
  
• 36-hour 500 millibar heights/vorticity, 700 millibar heights/mean humidity, pressure/thickness, precipitation/vertical velocity
  NGM (Nested Grid Model) Forecast Model. The top left panel show the heights and vorticity at 500 mb. The top right panel shows the MSL pressure and 1000-500 mb thickness. The lower left panel shows the 700 mb height and relative humidity. The lower right panel shows the total precipitation and 700 mb vertical velocity.
       Update time(s): 0510z, 1713z
       Coverage Area: North America
  
• 48-hour 500 millibar heights/vorticity, 700 millibar heights/mean humidity, pressure/thickness, precipitation/vertical velocity
  NGM (Nested Grid Model) Forecast Model. The top left panel show the heights and vorticity at 500 mb. The top right panel shows the MSL pressure and 1000-500 mb thickness. The lower left panel shows the 700 mb height and relative humidity. The lower right panel shows the total precipitation and 700 mb vertical velocity.
       Update time(s): 0520z, 1723z
       Coverage Area: North America
  

AVN/MRF (Spectral) Forecasts

• Initial to 36-hour 500 millibar heights/vorticity
  Chart shows AVN model forecast 500mb heights and vorticity over North America.
       Update time(s): 0633z, 2022z
       Coverage Area: North America
  
• 36-hour 500 millibar heights/wind speeds
  Chart shows MRF forecast of 500mb heights and isotachs over North America and surroundiing areas.
       Update time(s): 0746z, 2152z
       Coverage Area: North America
  
• 48-hour 500 millibar heights/vorticity
  Chart shows MRF forecast 500mb heights and vorticity over North America.
       Update time(s): 0750z, 2033z
       Coverage Area: North America
  
• 72-hour 500 millibar heights
  Chart shows forecast MRF 500mb heights over North America and polar regions.
       Update time(s): 0951z, 2206z
       Coverage Area: North America
  
• 84-hour 500 millibar heights
  Chart shows MRF forecast 500mb heights over Northern Hemisphere.
       Update time(s): 1053z
       Coverage Area: Northern Hemisphere
  
• 60-hour 500 millibar heights/vorticity, 700 millibar heights/mean humidity, pressure/thickness, 850 millibar heights/temperature
  Four panel chart.First panel shows forecast 500mb heights and vorticity. Second panel shows forecast MSL pressure and 1,000-500mb thickness. Third panel shows forecast 700mb heights and relative humidity, and fourth panel shows forecast 850mb heights and temperatures.
       Update time(s): 0944z, 2346z
       Coverage Area: North America
  
• 24-hour thickness, 700 millibar heights/wind speeds
  2 panel chart with 24 hour MRF forecast 850 mb heights/850-500 thickness; 700 mb heights/wind speeds
       Update time(s): 0014z
       Coverage Area: North America
  
• 36-hour 300 millibar heights/wind speeds
  Chart shows MRF forecast of 300mb heights and isotachs over North America and surrounding areas.
       Update time(s): 010z, 0925z
       Coverage Area: North America
  
• 12 to 48-hour humidity, vertical velocity
  Four panel chart shows 12, 24, 36 & 48 hour MRF forecasts of relative humidity and vertical velocities over North America.
       Update time(s): 0810z, 2209z
       Coverage Area: North America
  

LFM Forecasts

• Initial to 36-hour 500 millibar heights/vorticity
  Four panel chart showing progression of heights/vorticity at 500 mb, beginning with actual observed heights through the next 36 hours over North America.
       Update time(s):0329z
       Coverage Area: North America
  

• Flight Level 340
  Chart shows 24-hour forecast temperatures, wind speed and direction at 34,000 feet over entire geographic region.
       Update time(s): 0036z,0836z, 1211z, 1925z
       Coverage Area: North America, Europe & Atlantic Areas
  
• Flight Level 340
  Chart shows 24-hour forecast temperatures, wind speed and direction at 34,000 feet over entire geographic region.
       Update time(s): 0046z, 0649z, 1236z, 1903z
       Coverage Area: Northern North America, Pacific & Asia
  
• Flight Level 340 Chart shows 24-hour forecast temperatures, wind speed and direction at 34,000 feet over entire geographic region.
       Update time(s): 0041z, 0703z, 1220z, 1909z
       Coverage Area: Australia and the Pacific
  
• Flight Level 340
  Chart shows 24-hour forecast temperatures, wind speed and direction at 34,000 feet over entire geographic region.
       Update time(s): 0825z, 1225z, 1931z, 2303z
       Coverage Area: U.S., South & Central America
  
• Flight Level 450
  Chart shows 24-hour forecast temperatures, wind speed and direction at 45,000 feet over entire geographic region.
       Update time(s): 0052z, 0644z, 1250z, 2108z
       Coverage Area: Australia and the Pacific
  
• Flight Level 450
  Chart shows 24-hour forecast temperatures, wind speed and direction at 45,000 feet over entire geographic region.      Update time(s): 0143z, 0841z, 1150, 2009z
       Coverage Area: U.S., South & Central America
  
• Flight Level 450
  Chart shows 24-hour forecast temperatures, wind speed and direction at 45,000 feet over entire geographic region.
       Update time(s): 0639z, 1137z, 2103z, 2239z
       Coverage Area: Asia, Europe, Oceans, and Northern North America
  
• Flight Level 240
  Chart shows 24-hour forecast temperatures, wind speed and direction at 24,000 feet over entire geographic region.
       Update time(s): 0805z, 1142z, 2039z, 2251z
       Coverage Area: North America, Europe & Atlantic
  

Surface/Low Level Weather Maps and Charts

• U.S. Surface Analysis
  Chart shows surface high and low pressure centers and frontal systems. Each reporting station shows wind direction and speed, cloud cover, visibility, temperature, dew point, precipitation type and amounts, and barometric pressure.
       Update time(s): 0437z, 1041z, 1640z, 2239z
       Coverage Area: Continental U.S.
  
• North America and nearby areas
  Chart shows surface high and low pressure centers and frontal systems. Each reporting station shows wind direction and speed, cloud cover, visibility, temperature, dew point, precipitation type and amounts, and barometric pressure.
       Update time(s): 0132z, 0738z, 1336z, 1943z
       Coverage Area: North America & Surrounding Areas
  
• Atlantic Tropical Analysis
  Chart shows surface high and low pressure centers and frontal systems. Each reporting station shows wind direction and speed, cloud cover, visibility, temperature, dew point, precipitation type and amounts, and barometric pressure.
       Update time(s): 1015z
       Coverage Area: Atlantic Basin
  
• Tropical Eastern Hemisphere
  Chart shows high and low pressure centers and stream lines; satellite winds are shown from low cloud motions. Each reporting station shows wind direction and speed, cloud cover, temperature, dew point, precipitation amounts, and barometric pressure, pressure tendencies and changes in pressure.
       Update time(s): 0104z, 0934z
       Coverage Area: Tropical Eastern Hemisphere
  
• Tropical Western Hemisphere
  Chart shows high and low pressure centers and stream lines; satellite winds are shown from low cloud motions. Each reporting station shows wind direction and speed, cloud cover, temperature, dew point, precipitation amounts, and barometric pressure, pressure tendencies and changes in pressure.
       Update time(s): 0538z, 2135z
       Coverage Area: Tropical Western Hemisphere
  
• Pacific Ocean and nearby areas
  Chart shows high and low pressure centers and frontal systems. Each reporting station shows wind direction and speed, cloud cover, visibility, temperature, dew point, precipitation type and amounts, and barometric pressure.
       Update time(s): 0301z, 0909z, 1510z, 2125z
       Coverage Area: Pacific Ocean & Surrounding Areas
  
• Atlantic Ocean and nearby areas
  Chart shows high and low pressure centers and frontal systems. Each reporting station shows wind direction and speed, cloud cover, visibility, temperature, dew point, precipitation type and amounts, and barometric pressure.
       Update time(s): 0315z, 0917z, 1520z, 2144z
       Coverage Area: Atlantic Ocean & Surrounding Areas
  

Forecast Weather

• 24-hour MRF Surface/Thickness prog
  Chart shows forecast high and low pressure centers, and 1000-500mb thickness over North America.
       Update time(s): 0732z, 2118z
       Coverage Area: North America
  
• 36-hour MRF Surface/Thickness prog
  Chart shows forecast high and low pressure centers, and 1000-500mb thickness over North America.
       Update time(s): 0735z, 2056z
       Coverage Area: North America
  
• 48-hour MRF Surface/Thickness prog
  Chart shows forecast high and low pressure centers, and 1000-500mb thickness over North America.
       Update time(s): 0753z, 2115z
       Coverage Area: North America
  
• Surface prog for Days 3, 4, 5, & 108-hour 1000/500 millibar thickness/surface prog
  Four panel chart:Charts show forecast high and low pressure centers, surface frontal systems and isobars for Days 3, 4 and 5. Last panel depicts forecast 500 mb heights and departures from normal readings.
       Update time(s): 2003z
       Coverage Area: North America & Polar Regions
  

Thickness

• 1000-500 millibar Thickness Analysis
  Chart shows high and low pressure centers, and surface frontal systems. Also shows 1000-500 mb thickness in decameters over North America.
       Update time(s): 0535z, 1729z
       Coverage Area: North America
  
• 12-hour 1000-500 millibar Thickness/Surface prog
  Chart shows forecast high and low pressure centers, and frontal systems. Also shows 1000-500 mb thickness in decameters over North America.
       Update time(s): 0657z, 1844z
       Coverage Area: North America
  
• 24/36-hour 1000-500 millibar Thickness/Surface prog
  Chart shows forecast high and low pressure centers, frontal systems. Also shows 1000-500 mb thickness in decameters over the northern Pacific.
       Update time(s): 0728z, 2121z
       Coverage Area: Northern Pacific Areas
  
• 48-hour 1000-500 millibar Thickness/Surface prog
  Chart shows forecast high and low pressure centers, frontal systems. Also shows 1000-500 mb thickness in decameters.
       Update time(s): 1003z, 2236z
       Coverage Area: U.S., Atlantic, Europe
  
• 72 to 120 hour 1000/500 millibar thickness/surface prog
  Four panel chart shows forecast high and low pressure centers, frontal systems. Also shows 1000-500 mb thickness in decameters.
       Update time(s): 1205z
       Coverage Area: North America
  

Miscellaneous Maps and Charts

• Observed Minimum Temperatures
  Chart shows observed minimum temperatures for 12 hours ending at 12z.
       Update time(s): 1306z
       Coverage Area: Continental U.S. & Southern Canada
  
• Observed Maximum Temperatures
  Chart shows observed maximum temperatures for 12 hours ending at 0z.
       Update time(s): 0206z
       Coverage Area: Continental U.S. & Southern Canada
  
• Maximum/Minimum Temperatures prog
  Four panel chart shows 24 hour and 48 hour forecast minimum temperatures. Also shows 36 hour and 60 hour forecast maximum temperatures.
       Update time(s): 0403z
       Coverage Area: Continental U.S.
  

• Sunshine/Solar Energy prog
  Four panel chart: Upper two panels show 24-hour and 48-hour forecast sunshine; hours are plotted, percentages expressed with contours. Lower two panels show 24-hour and 48-hour forecast; solar energy plotted at 10 x Kwh/m2; Kmh/m2 expressed with contours.
       Update time(s): 0411z
       Coverage Area: Continental U.S.
  
• Sunshine prog
  Two panel chart showing 36-hour and 60-hour forecast sunshine. Hours are plotted, percentages expressed with contours.
       Update time(s): 1547z
       Coverage Area: Continental U.S.
  

• Snow Cover Analysis (Available winter season)
       Update time(s): 1217z
       Coverage Area:
  
• Observed 24-hour precipitation
  Observed 24-hour precipitation ending at 12z. Precipitation shown to the nearest 0.01 inches. T equals trace.
       Update time(s): 1309z
       Coverage Area: Continental U.S.
  
• 18, 30, 42, & 54-hour precipitation prog
  Four panel chart shows probability and type of precipitation at the midpoints of those time      Update time(s): 0407z, 1549z
       Coverage Area: Continental U.S.
  
• Quantitative precipitation/excess rain/heavy snow prog 24-hour
  Four panel chart. Chart 1 shows prognosis of quantitative precip from 06z-12z. Chart 2 shows prognosis from 12z-18z. Chart 3 & 4 show forecast excessive rain and heavy snow over the continental U.S.
       Update time(s): 1203z
       Coverage Area: Continental U.S.
  
• Quantitative precipitation/excess rain/heavy snow prog 48-hour
  Same as Chart above, except for forecast period.
       Update time(s): 1451z
       Coverage Area: Continental U.S.
  
• Heavy rain/snow prog
  Heavy Rain / Snow Prognosis. Four panel chart showing forecasted precipitation amounts for selected time periods. Bottom panel depicts areas which have the potential for heavy rain or snow to occur over the period indicated.
       Update time(s): 0233z, 0726z, 1203z, 1344z, 1451z, 1941z
       Coverage Area: Continental U.S.
  
• Quantitative precipitation/excess rain/heavy snow prog 6-hour
  Same as 2 charts above, except for forecast period.
       Update time(s): 0233z
       Coverage Area: Continental U.S.
  
• Quantitative precipitation/excess rain/heavy snow prog 12-hour
  Quantitative Precipitation/Excessive Rain/Heavy Snow prog (beginning 00z). Same as chart above, except for forecast period.
       Update time(s): 0726z
       Coverage Area: Continental U.S.
  

• Crop Moisure Index (available Tues.)
  Chart depicts week-to-week abnormal dryness/wetness affecting agriculture during the warm season.
       Update time(s): 2322z Tuesdays
       Coverage Area: Continental U.S.
  
• Crop Moisure Index by Division (available Tues.) Chart depicts abnormal dryness/wetness affecting agriculture by state agricultural divisions.
       Update time(s): 2324z Tuesdays
       Coverage Area: Continental U.S.
  

• 3-5 Day Forecast Daily temperature/precipitation anomalies
  Top charts show 24 hour predicted precipitation anomalies. The lower charts show predicted departure of temperatures from the normal for the period.
       Update time(s): 2046z
       Coverage Area: Continental U.S.
  
• 5 Day Forecast Mean temperature/precipitation anomalies
  Top chart show the forecast 5 day mean minimum temperature anomaly. The center chart show the forecast 5 day mean maximum temperature anomaly. The bottom chart shows the forecast 5 day total precipitation.
       Update time(s): 2113z
       Coverage Area: Continental U.S.
  
• 30 day and 90 day outlooks (issued the middle of each month)
  These are the standard monthly 30 and 90 day weather outlooks issued by the NWS. They are issued once a month -- generally within a few days of the 15th. The 0.5 indicates they have a half month lead time before the forecast begins. The information is presented as percentages above 33% chance of the event taking place -- above, near or below normal -- with insufficient data, use climatology across the remainder of the nation.
       Update time(s): 2256z 15th of each month
       Coverage Area: Continental U.S.
  
• Seasonal Outlooks 1.5 and 2.5 month lead time
  These are seasonal (30 and 90 day) weather outlooks issued by the NWS that are issued in advance. The table below indicates the amount of lead time for the 30 and 90 day outlooks. The number at the beginning of the description indicates the lead time before the forecast begins (1.5 would be 1.5 months, 12.5 would be a year and half a month). The information is presented as percentages above 33% chance of the event taking place -- above, near or below normal -- with insufficient data, use climatology across the remainder of the nation.
       Update time(s): 2353z Tuesday, Thursday & Sunday
       Coverage Area: Continental U.S.
  
• Seasonal Outlooks 3.5 and 4.5 month lead time
  Same as above, except for lead time.
  
• Seasonal Outlooks 5.5 and 6.5 month lead time
  Same as above, except for lead time.
  
• Seasonal Outlooks 7.5 and 8.5 month lead time
  Same as above, except for lead time.
  
• Seasonal Outlooks 9.5 and 10.5 month lead time
  Same as above, except for lead time.
  
• Seasonal Outlooks 11.5 and 12.5 month lead time
  Same as above, except for lead time.
  

Ocean and Marine

• 12 & 24-hour Wave direction/Period prog
  Two panel chart depicts wave directions and primary wave periods plotted in seconds for both 12-hr and 24-hr forecast periods.
       Update time(s): 1109z, Forecast Period: 12 & 24 hour
       Coverage Area: Atlantic and Pacific Oceans
  
• 12 & 24-hour Wind/Wave height prog
  The height of the waves in the eastern and central Pacific and Gulf of Mexico along with the period of time between waves or the frequency of waves.
       Update time(s): 1115z, Forecast Period: 48 & 72 hour
       Coverage Area: Atlantic and Pacific Oceans
  
• 48 & 72-hour Wave direction/Period prog
  Two panel chart depicts wind direction and significant wave heights plotted in feet for both 48-hr and 72-hr forecast periods.
       Update time(s): 1104z, Forecast Period: 12 & 24 hour
       Coverage Area: Atlantic and Pacific Oceans
  
• 48 & 72-hour Wind/Wave height prog
  Two panel chart depicts wind direction and significant wave heights, plotted in feet for 48-hr and 72-hr forecast periods.
       Update time(s):1106z, Forecast Periods: 48 & 72 hour
       Coverage Area: Atlantic and Pacific Oceans
  
• Gulf of Mexico 12 & 48-hour Wave Height/Direction prog
  Five panel chart depicts wave heights and wind directions for 12-hr and 48-hr forecast periods.
       Update time(s):0423z, 1605z, Forecast period: 12 & 48 hour
       Coverage Area: Gulf of Mexico
  
• Atoll Wind Analysis
  Chart depicts a streamline analysis of surface winds in the Tropical Atlantic.
       Update time(s): 0342z, 1504z
       Coverage Area: Tropical Atlantic Ocean
  
• 5 Day Mean 500 millibar Heights, 6-10 Day Temperature Anomalies, 6-10 day Total Precipitation
       Update time(s): 2100z Monday, Wednesday & Friday
       Coverage Area: North America, specifically United States
  

What is Greenwich Mean (z) Time

For example, if local Eastern Standard Time is 6:00pm, convert this to 1800 on the 24-hour clock, then add 5 hours = 2300GMT for 2300z Time. If local Mountain Daylight Savings Time is 1:00pm, convert this to 1300 on a 24-hour clock, then add 6 hours = 1900GMT or 1900z.

1. Go to Page Setup under the File menu. Make sure that you select the appropriate orientation (this will most often be landscape, or the second "horizontal" icon.
2. Enter an appropriate reduce percentage. This percentage will vary depending the image. (Some experimentation may be necessary the first time you print a specific map.)

1. Choose File/Print from the browser menu.
2. Choose "Properties" to see your printer setup.
3. Find a section called "Scaling" and change the percentage from 100 to about 50%. Because of the differing sized of our DIFAX charts, you may have to fine tune the scaling depending on which map you are trying to print. Most charts are best printed at a scale between 40 and 60%.
4. Make sure that the "Orientation" section is set to the correct value for the orientation of your DIFAX chart.
5. Hit "OK" twice.

1. When the DIFAX chart is displayed in your browser window, choose File/Save from the browser menu.
2. Pick a directory to save to, type a filename to save to (example: printme.gif), and hit "Save."
3. The DIFAX chart is now stored on your PC and you can open it with your Image Viewer to print. For specific instructions on how to print your DIFAX chart from your Image Viewer please refer to the Image Viewer's Help section.

© 1999 AccuWeather, Inc.
For the use of subscriber exclusively, redistribution prohibited.