Data Format (ENGLISH) Field length of each data element listed in parentheses. Data output files have field numbers preceeding each year's data to identify the elements selected. Field Element Values Definition 1 Station ID 00000 - Station Number (WBAN) (5) 99999 (1) ASOS Flag blank An "A" in this field indicates or A that the observations are from an ASOS station @@@ 2 Time (4) Year 1990 - Year of observation 1995 (2) Month 01-12 Month of observation (2) Day 01-31 Day of month (2) Hour 01-24 Hour of day in local standard time @@@ 3 GRAD 0000 - Global radiation. Hourly values (4) 1415 are one-minute samples summed over the hour and divided by 60 to obtain the mean hourly value ending on the hour indicated in Local Standard Time (LST). 9999 indicates missing. (Nearest tenth watt per meter squared). 4 DRAD 0000 - Direct radiation. Hourly values (4) 1415 are one-minute samples summed over the hour and divided by 60 to obtain the mean hourly value ending on the hour indicated in Local Standard Time (LST). 9999 indicates missing. (Nearest tenth watt per meter squared). @@@ 5 Total Sky Cover 00 - 10 Amount of sky dome (in tenths) (2) covered by clouds. 99 = missing. 6 Opaque Sky Cover 00 - 10 Amount of sky dome (in tenths) (2) covered by clouds that prevent observing the sky or higher cloud layers. 99 = missing data. 7 Dry Bulb -94.0 Dry bulb temperature in degrees (5) Temperature to 140.0 Fahrenheit. 999.9 = missing data. (1) Dry Bulb Temperature blank An "I" in this field indicates Interpolation Flag or I that the dry bulb temperature was linearly interpolated. 8 Dew Point -94.0 Dew point temperature in degrees (5) Temperature to 140.0 Fahrenheit. 999.9 = missing data. @@@ 9 Relative Humidity 000 - Relative humidity in percent. (3) 100 999 = missing data. 10 Station 2067 - Station atmospheric pressure in (4) Pressure 3248 hundredths of inches. 9999 = missing data. (1) Station Pressure blank An "I" in this field indicates Interpolation Flag or I that the station pressure was linearly interpolated. 11 Wind Direction 000 - Wind direction in degrees. (3) 360 (N = 360, E = 90, S = 180, W = 270) 999 = missing data. 12 Wind Speed 0.0 - Wind speed in miles per hour. (4) 99.0 99.9 = missing data. @@@ 13 Visibility 0.0 - Horizontal visibility in (6) 777.7 miles. 777.7 = unlimited visibility. 9999.9 = missing data. 14 Ceiling Height 00000 - Ceiling height in feet. (5) 99900 77777 = unlimited ceiling height. 88888 = cirroform. 99999 = missing data. 15 Present Weather See Present weather conditions (8) Table denoted by left justified pairs Below of digits. See present weather table below. @@@ 16 ASOS CLOUD LAYER 1 See Sky condition and height (5) Table for first layer. Data-value = Below XXYYY. XX = code for sky condition. YYY = The layer height (hundreds of feet). 99999 = missing data. See Sky Condition table below. 17 ASOS CLOUD LAYER 2 See Sky condition and height for (5) Table second layer. Data-value = XXYYY. Below XX = code for sky condition. YYY = The layer height (hundreds of feet). 99999 = missing data. See Sky Condition table below. @@@ 18 ASOS CLOUD LAYER 3 See Sky condition and height for (5) Table third layer. Data-value = XXYYY. Below XX = code for sky condition. YYY = The layer height (hundreds of feet). 99999 = missing data. See Sky Condition table below. 19 Hourly Precipitation 0 - 999 Rainfall in hundredths of inches (3) for the past hour. (1) Hourly Precipitation blank, A, See 'Data Format--Hourly Flag D, or M Precipitation' section below. 20 Snow Depth 000 - Snow depth in inches on the (3) 100 day indicated. 999 = missing data. @@@ Sky Conditions Table Position Element Values Remarks 1 Sky Condition 00 clear or less than .1 coverage (2) 02 scattered .1 to .5 coverage 04 broken .6 to .9 coverage 06 overcast 1.0 coverage 07 obstruction 1.0 coverage 09 unknown @@@ Present Weather Codes (PWTH) Present weather codes are two characters in length. The leftmost character indicates the general class of present weather while the rightmost character is a qualifier. The two digit codes are stored left justified into the eight digits of the DATA-VALUE portion. If there is no occurrence of present weather the valid DATA-Value will always be 99999999. PWTH DATA-VALUE code descriptions CODE FOR PWTH RANGE 00 00 ********** No Occurrence where: 00 = No present weather occurred @@@ CODE FOR PWTH RANGE 10 TO 19 1X ********** Thunderstorm, Tornado, Squall where: X = 0 thunderstorm - lightning and thunder. wind gust < 50 knots - hail < .75 in. = 1 heavy or severe thunderstorm, frequent intense lightning and thunder. Wind gust 50 knots or greater - hail .75 in.or greater. = 2 report of tornado or water spout = 3 light squall (through May 1951 only) = 4 moderate squall - Beginning in June 1951, only this code (14) is recorded. = 5 heavy squall (through May 1951 only) = 6 water spout (began Jan 1984) = 7 funnel cloud (began Jan 1984) = 8 tornado (began Jan 1984) = 9 unknown @@@ Code 13 and 15 are recorded beginning in January 1949 and ending in May 1951. Prior to 1949 rain squalls are distinguished from snow squalls and recorded in separate general classes of present weather. A squall is a sudden increase of wind speed by at least 16 knots, reaching 22 knots or more and lasting for at least one minute. CODE FOR PWTH RANGE 20 TO 29 2X ********* Rain, Rain Showers, Freezing Rain where: X = 0 light rain = 1 moderate rain = 2 heavy rain = 3 light rain showers = 4 moderate rain showers = 5 heavy rain showers = 6 light freezing rain = 7 moderate freezing rain = 8 heavy freezing rain = 9 unknown @@@ Light = Trace (< .005 in.) to .10 inches per hour Moderate = .11 to .30 inches per hour Heavy = > .30 inches per hour CODE FOR PWTH RANGE 30 TO 39 3X ********* Rain Squalls, Drizzle, Freezing Drizzle where: X = 0 light rain squalls (through 1948 only) = 1 moderate rain squalls (through 1948 only) = 2 heavy rain squalls (through 1948 only) = 3 light drizzle = 4 moderate drizzle = 5 heavy drizzle = 6 light freezing drizzle = 7 moderate freezing drizzle = 8 heavy freezing drizzle = 9 unknown @@@ When drizzle or freezing drizzle occurs with other weather phenomena: Light = Trace (< .005 in.) to .01 inches per hour Moderate = > .01 to .02 inches per hour Heavy = > .02 inches per hour When drizzle or freezing drizzle occurs alone: Light = Visibility 5/8 mile or greater Moderate = Visibility 5/16 - 1/2 mile Heavy = Visibility 1/4 mile or less @@@ CODE FOR PWTH RANGE 40 TO 49 4X ********* Snow, Snow Pellets, Ice Crystals where: X = 0 light snow = 1 moderate snow = 2 heavy snow = 3 light snow pellets = 4 moderate snow pellets = 5 heavy snow pellets = 6 light ice crystals = 7 moderate ice crystals = 8 heavy ice crystals = 9 unknown Beginning April 1963 any occurrence of ice crystals is recorded as a 47. Prior to this date intensities were reported. @@@ CODE FOR PWTH 50 TO 59 5X ********* Snow Showers, Snow Squalls, Snow Grains where: X = 0 light snow showers = 1 moderate snow showers = 2 heavy snow showers = 3 light snow squall (through 1948 only) = 4 moderate snow squall (through 1948 only) = 5 heavy snow squall (through 1948 only) = 6 light snow grains = 7 moderate snow grains = 8 heavy snow grains = 9 unknown @@@ CODE FOR PWTH RANGE 60 TO 69 6X ********* Sleet, Sleet Showers, Hail where: X = 0 light ice pellet showers = 1 moderate ice pellet showers = 2 heavy ice pellet showers = 3 light hail = 4 moderate hail = 5 heavy hail = 6 light small hail = 7 moderate small hail = 8 heavy small hail = 9 unknown Prior to April 1970 ice pellets were coded as sleet. Beginning April 1970 sleet and small hail were redefined as ice pellets and are coded as 60, 61 or 62. Beginning Sep 1956 intensities of hail were no longer reported and all occurrences were recorded as a 64. @@@ CODE FOR PWTH RANGE 70 TO 79 7X ********* Fog, Blowing Dust, Blowing Sand where: X = 0 fog = 1 ice fog = 2 ground fog = 3 blowing dust = 4 blowing sand = 5 heavy fog = 6 glaze (begin 1984) = 7 heavy ice fog (begin 1984) = 8 heavy ground fog (begin 1984) = 9 unknown These values recorded only when visibility less than 7 miles. @@@ CODE FOR PWTH RANGE 80 TO 89 8X ******** Smoke, Haze, Smoke and Haze, Blowing Snow, Blowing Spray, Dust where: X = 0 smoke = 1 haze = 2 smoke and haze = 3 dust = 4 blowing snow = 5 blowing spray = 6 dust storm (begin 1984) = 7 volcanic ash (begin Aug.1992) = 8 not used = 9 unknown These values recorded only when visibility less than 7 miles. @@@ CODE FOR PWTH RANGE 90 TO 92 AND 99 9X ********* Ice Pellets where: X = 0 light ice pellets = 1 moderate ice pellets = 2 heavy ice pellets = 9 unknown @@@ Hourly Precipitation Codes The actual precipitation data value: The data value portion is a three-digit integer. Units are inches and hundredths. Range = 000-999. Hourly Precipitation Flag: A Accumulated period and amount. An accumulated period indicates that the precipitation amount is correct, but the exact beginning and ending times are only known to the extent that the precipi- tation occurred sometime within the accumulation period. Begin accumulation data value will always be 999. D Deleted Flag. Beginning and ending of a deleted period. A deleted value indicates that the original data were received, but were unreadable or clearly recognized as noise. @@@ M Missing Flag. A missing flag indicates that the data were not received. b Blank. No Flag needed. Examples: The precipitation accumulation from 1st month day 02 to 2nd month day 04: Month Day Hour Value 01 02 05 030b 10 999A Accumulation begins 02 01 01 999A Accumulation continues 04 14 390A Accumulation ends @@@ Accumulated precipitation for 1 month only: Month Day Hour Value 01 02 10 999A Accumulation begins 31 24 320A Accumulation ends Required precipitation charts or forms were never received at NCDC: Month Day Hour Value 01 01 01 999M Missing data 31 01 999M 02 01 01 999M 28 01 999M @@@ STATIONS WITH NO HOURLY PRECIPITATION DATA: 24283 Arcata, CA 14940 Mason City, IA 27502 Barrow, AK 94725 Massena, NY 26615 Bethel, AK 24025 Pierre, SD 26533 Bettles, AK 23184 Prescott, AZ 93129 Cedar City, UT 23153 Tonopah, NV 14991 Eau Claire, WI 14850 Traverse City, MI 25507 Homer, AK 26442 Valdez, AK 26616 Kotzebue, AK 93738 Washington-Dulles Arpt., VA 93987 Lufkin, TX 14778 Williamsport, PA STATIONS WITH NO SNOW DATA: 24283 Arcata, CA 24149 Lewiston, ID