U.S. Weather Bureau reference card: Key to Aviation Weather Reports and Forecasts (rev. May 1970)
Document date May 1970
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Id: Cooper-Part-83:003-004
Subject: Cooper Files: Cooper-Part-83:003-004 Document: U.S. Weather Bureau reference card: Key to Aviation Weather Reports and Forecasts (rev. May 1970) Id: Cooper-Part-83:003-004 Page: https://cooper.theunsolved.net/documents/Cooper-Part-83%3A003-004 What is wrong (title, date, type, which pages belong together, copies)? What does the scan show?
A person reads every report. Corrections are made by hand, to the data — titles, dates, names, which pages belong together — never to the scans, and they can take a while to appear.
FBI 164-81, Vault Part 83 pp. 3–4 (DB Cooper-35324–35325), Report, dated May 1970 — cooper.theunsolved.net/documents/Cooper-Part-83%3A003-004
LOCATION IDENTIFIER AND TYPE OF REPORT* | SKY AND CEILING | VISIBILITY WEATHER AND OBSTRUCTION TO VISION | SEA-LEVEL PRESSURE | TEMPERATURE AND DEW POINT | WIND | ALTIMETER SETTING | RUNWAY VISUAL RANGE | CODED PIREPS MKC | 150M250 | 1R-K | 132 | /58/56 | /1807 | /993/ | R04LVR20V40 | /055
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SKY Sky cover symbols are in ascending order. Figures preceding symbols are heights in hundreds of feet above station. Sky cover symbols are: ○ Clear: Less than 0.1 sky cover ⊙ Scattered: 0.1 to less than 0.6 sky cover ◉ Broken: 0.6 to 0.9 sky cover ⊕ Overcast: More than 0.9 cover — Thin (When prefixed to the above symbols) -X Partly obscured: 0.1 to less than 1.0 sky hidden by precipitation or obstruction to vision (bases at surface) X Obscured: 1.0 sky hidden by precipitation or obstruction to vision (bases at surface)
CEILING Letter preceding height of layer identifies ceiling layer and indicates how ceiling height was obtained. Thus A Aircraft B Balloon (ceiling, pilot or raob) E Estimated M Measured R Radar W Indefinite "V" Immediately following numerical value indicates a variable ceiling height
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VISIBILITY Reported in Statute Miles and Fractions. (V=Variable) WEATHER AND OBSTRUCTION TO VISION SYMBOLS A Hail IC Ice Crystals RW Rain Showers BD Blowing Dust IF Ice Fog S Snow BN Blowing Sand IP Ice Pellets SG Snow Grains BS Blowing Snow IPW Ice Pellet SP Snow Pellets Showers SW Snow Showers D Dust T Thunderstorm F Fog K Smoke T+ Severe Thunderstorm GF Ground Fog L Drizzle ZL Freezing Drizzle H Haze R Rain ZR Freezing Rain
Precipitation intensities are indicated thus: -- Very Light; -Light; (no sign) Moderate; + Heavy WIND Direction in tens of degrees from true north, speed in knots. 0000 indicates calm. G indicates gusty. Peak speed follows G or Q when gusts or squalls are reported. The contraction WSHFT followed by local time group in remarks indicates windshift and its time of occurrence. (Knots X 1.15=statute mi/hr.) EXAMPLES: 3627 360 Degrees, 27 Knots; 3627G40 360 Degrees, 27 Knots. Peak speed in gust 40 knots. ALTIMETER SETTING The first figure of the actual altimeter setting is always omitted from the report.
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RUNWAY VISUAL RANGE (RVR) RVR is reported from some stations. Extreme values for 10 minutes prior to observation are given in hundreds of feet. Runway identification precedes RVR report.
CODED PIREPS Pilot reports of clouds not visible from ground are coded with MSL height data preceding and/or following sky cover symbol to indicate cloud bases and/or tops respectively.
DECODED REPORT Kansas City: Record observation, 1500 feet scattered, measured ceiling 2500 feet overcast, visibility 1 mile, light rain, smoke, sea level pressure 1013.2 millibars, temperature 58°F, dewpoint 56°F, wind 180°, 7 knots, altimeter setting 29.93 inches, runway 04 left, visual range 2000 ft. variable to 4000. Pilot reports top of overcast 5500 feet (MSL).
DB Cooper-35324
*TYPE OF REPORT The omission of type-of-report data identifies a scheduled record observation for the hour specified in the sequence heading; the time of an out-of-sequence, special observation is given at "S" followed by a time group (24-hour clock GMT) e.g., PIT S 0715 -XM10... A special indicates a significant change in one or more elements. Local reports are identified by "LCL" and a time group. Locals are transmitted on local teletypewriter circuits only.
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U.S. DEPARTMENT OF COMMERCE • ENVIRONMENTAL SCIENCE SERVICES ADMINISTRATION • WEATHER BUREAU • Washington, D.C. • Revised MAY 1970
KEY TO AVIATION WEATHER FORECASTS........
TERMINAL FORECASTS contain information for specific airports on ceiling, cloud heights, cloud amounts, visibility, weather condition and surface wind. They are written in a form similar to the AVIATION WEATHER REPORT.
CEILING: Identified by the letter "C" CLOUD HEIGHTS: In hundreds of feet above the station (ground) CLOUD LAYERS: Stated in ascending order of height VISIBILITY: In statute miles, but omitted if over 8 miles SURFACE WIND: In tens of degrees and knots; omitted when less than 10
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SIGMET or AIRMET warns airmen in flight of potentially hazardous weather such as squall lines, thunderstorms, fog, icing, and turbulence. SIGMET concerns severe and extreme conditions of importance to all aircraft. AIRMET concerns less severe conditions which may be hazardous to some aircraft or to relatively inexperienced pilots. Both are broadcast by FAA on NAVAID voice channels.
WINDS AND TEMPERATURES ALOFT (FD) FORECASTS are computer prepared forecasts of wind direction (nearest 10° true N) and speed (knots) for selected flight levels. Temperatures are forecast for all levels shown except that no forecasts are issued for the 3000 ft. level or other levels within 2500 feet of a station's elevation.
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EXAMPLE OF TERMINAL FORECASTS
C15⊕ Ceiling 1500', broken clouds O11/2GF Clear, visibility one and one-half miles, ground fog
.CSX1/4S+ Sky obscured, vertical visibility 500 ft. visibility one-fourth mile, heavy snow 200⊕C70⊕6K 3230G Scattered clouds at 2000', ceiling 7000' overcast. Visibility 6 miles, smoke, surface wind 320 degrees 30 knots, gusty
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EXAMPLES OF WINDS AND TEMPERATURES ALOFT (FD) FORECASTS:
FD WBC 121745 BASED ON 121200Z DATA VALID 1300OZ FOR USE 1800-0300Z. TEMPS NEG ABV 24000
FT 3000 6000 9000 12000 18000 24000 30000 34000 39000
BOS 3127 3425-07 3420-11 3421-16 3516-27 3512-38 311649 292451 283451 JFK 3926 3327-08 3324-12 3322-16 3120-27 2923-38 284248 285150 285749
At 60000 feet ASL over JFK wind from 330° at 27 knots and temperature minus 8° C.
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AREA FORECASTS are 12-hour forecasts plus 12-hour OUTLOOKS (18-hour outlook in FA valid at 1300Z) of cloud, weather and frontal conditions for an area the size of several states. Heights of cloud tops, icing, and turbulence are ABOVE SEA LEVEL (ASL); ceiling heights, ABOVE GROUND LEVEL (AGL); bases of cloud layers are ASL unless indicated. Area forecasts are amended by SIGMETs or AIRMETs.
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PILOTS . . . report in-flight weather to nearest FSS DB Cooper-35325
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U.S. DEPARTMENT OF COMMERCE • ENVIRONMENTAL SCIENCE SERVICES ADMINISTRATION • WEATHER BUREAU • Washington, D.C. • Revised MAY 1970
GPO : 1970 O - 404-111 For Sale by the Superintendent of Documents, U.S. Government Printing Office, Washington, D.C., 20402 Price 5 cents; $2.50 per 100