<<

Code Code Code mph knots ABBREVIATION cH High Cloud Description cM Middle Cloud Description cL Low Cloud Description Nh N COVERAGE ff Cu of fair with little vertical development Filaments of Ci, or “mares tails,” scattered Thin As (most of cloud layer semi-transparent) No Calm Calm Symbolic and not increasing and seemingly flattened 0 St or Fs = Stratus or 1 1 1 Fractostratus Cu of considerable development, generally Dense Ci and patches or twisted sheaves, Thick As, greater part sufficiently dense to Less than one-tenth 1 - 2 1 - 2 usually not increasing, sometimes like remains towering with or without other Cu or Sc bases or one-tenth Ci = Cirrus hide sun (or moon), or Ns 1 2 of Cb; or towers or tufts 2 2 all at the same level Two-tenths or Cb with tops lacking clear cut outlines but 3 - 8 3 - 7 Dense Ci, often -shaped, derived from Thin Ac, mostly semi-transparent; cloud elements three tenths ff Cs = Cirrus distinctly not cirriform or anvil-shaped, or associated with Cb not changing much and at a single level 2 H 3 3 3 with or without Cu, Sc or St C Four-tenths 9 - 14 8 - 12 Cc = Cirrocumulus Ci, often hook-shaped,gradually spreading Thin Ac in patches; cloud elements continually Sc formed by the spreading out of Cu; Cu 3 dd 4 over the sky and usually thickening as a whole 4 changing and/or occurring at more than one level 4 often present also T T CM Five-tenths Ac = Altocumulus Ci and Cs, often in converging bands, or Cs alone; 15 - 20 13 - 17 PPP Thin Ac in bands or in a layer gradually spreading generally overspreading and growing denser; the Sc not formed by the spreading out of Cu 4 over the sky and usually thickening as a whole 5 continuous layer not reaching 45 degrees 5 5 As = Altostratus Six-tenths 21 - 25 18 - 22 Ci and Cs, often in converging bands, or Cs alone; 5 + Ac formed by the spreading out of Cu V V ww pp a generally overspreading and growing denser; the St or Fs or both but no Fs of bad weather Seven-tenths or - Sc = Stratocumulus 6 continuous layer exceeding 45 degrees altitude 6 6 26 - 31 23 - 27 6 eight-tenths N Double-layered Ac, or a thick layer of Ac, not Veil of Cs convering the entire sky Fs and/or Fc of bad weather; stratocumulus Ns = Nimbostratus increasing; or Ac with As and/or Ns under deck () Nine-tenths or 32 - 37 28 - 32 h t 7 7 7 7 overcast with openings Td Td CL N WR Cu and Sc (not formed by spreading out of Cu) Cu or Fc = Cumulus Cs not increasing and not covering entire sky Ac in the form of Cu-shaped tufts or Ac with turrets with bases at different levels Completely overcast or Fractocumulus 8 8 8 8 38 - 43 33 - 37 h RR Cb having a clearly fibrous (cirriform) top, Cc alone or Cc with some Ci or Cs, but the Ac of a chaotic sky, usually at different levels; Cb = Cumulonimbus often anvil-shaped, with or without Cu, Cc being the main cirriform cloud patches of dense Ci are usually present also Sky Obscured 44 - 49 38 - 42 9 9 9 Sc, St or scud 9 Code PAST 50 - 54 43 - 47 Weather Symbol Chart W WEATHER Sample Station Model Plot 0 1 2 3 4 5 6 7 8 9 Clear or few clouds 55 - 60 48 - 52 WW PRESENT WEATHER 0 Partly cloudy (scattered) or 61 - 66 53 - 57 variable sky HIGH CLOUD TYPE: cirrus (anvil-shaped) 00 Widespread in suspension Dust or sand raised by , Dust or sand storm within 1 Cloud development NOT State of sky on the whole Clouds generally forming or Well developed dust Clouds generally dissolving or reduced by smoke in the air, NOT raised by wind, sight of or at station during TOTAL SKY COVER: 6/8ths observed or NOT observable unchanged during past hour developing during past hour at of observation devil(s) within past hour becoming less developed during at time of observation past hour Cloudy (broken) during past hour past hour MIDDLE CLOUD TYPE: Altocumulus or overcast 67 - 71 58 - 62 2 : 75 F with tufts (castellanus) Sandstorm or : 1010.4 mb duststorm, or drifting 72 - 77 63 - 67 WEATHER: heard 75 or blowing 104 10 3 but no PRESSURE CHANGE: - .8 mb More or less continuous shallow Precipitation within sight, Precipitation within sight, Patches of shallow at station, visible, no thunder Precipitation within sight, but Thunder heard, but no (s) within sight during (s) within sight at station fog fog at station, NOT deeper than reaching the , but distant reaching the ground, near to NOT deeper than 6 feet on heard NOT reaching the ground precipitation at the station past hour during past hour Fog, or smoke 6 feet on land from station but NOT at station 78 - 83 68 - 72 or thick dust haze 3 -8 4 PRESSURE TENDENCY: VISIBILITY: 3 statute miles rising then falling 84 - 89 73 - 77 67 : 5 POINT: 67 F from the southeast 20 Drizzle (NOT and NOT (NOT freezing and NOT or Showers of snow, or of rain Showers of , or of hail (with or without Snow (NOT falling as showers) Rain and snow (NOT falling as (NOT falling as showers) during Showers of rain during past hour, Fog during past hour, but falling as showers) during past falling as showers) during past during past hour, but NOT at showers) during past hour, but and snow, during past hour, and rain, during past hour, precipitation) during past hour, .01 past hour, but NOT at time but NOT at time of observation NOT at time of observation 78 - 82 hour, but NOT at time of hour, but NOT at time of time of observation NOT at time of observation but NOT at time of observation but NOT at time of observation but NOT at time of observation Rain 90 - 94 observation observation of observation LOW CLOUD TYPE: cumulonimbus : 6 20 knots Snow, or , or 113 - 117 98 - 102 6-HOUR PRECIPITATION: .01 inches 7 pellets () 30 Severe or sand Slight or moderate dust storm or Slight or moderate dust storm or Slight or moderate dust storm Severe dust storm or sand Heavy drifting snow, Severe dust storm or sand storm, Slight or moderate drifting Heavy drifting snow, Slight or moderate drifting sand storm, has decreased sand storm, no appreciable or sand storm, has increased storm, has decreased during storm, no appreciable change generally high (s) has increased during past hour snow, generally low generally low snow, generally high 118 - 123 103 - 107 during the past hour change during past hour during past hour past hour during past hour 8 Thunderstorm, with or without 9 precipitation Explanation of Weather Symbols 40 Adapted from U.S. Weather Bureau, , World Meteorlogical Organization Fog, sky NOT discernible, no Fog, sky discernible, has Fog, sky NOT discernible, Fog at distance at time of Fog, sky discernible, has Fog, sky NOT discernable, Fog, sky discernible, no Fog, depositing rime, sky Fog, depositing rime, kky Fog in patches appreciable change during begun or become thicker has begun or become observation, but NOT at station become thinner during past hour has become thinner during appreciable change during discernible NOT dicernible PRESSURE Total amount of Predominate clouds of type in CLtable. during past hour N . CL during past hour past hour past hour past hour thicker during past hour Code a TENDENCY True direction from which the wind is Rising then falling dd blowing along arrow shaft toward CM Predominate clouds of type in CM table. 50 0 the station. intemittent drizzle (NOT Continuous drizzle (NOT Intermittent drizzle (NOT Continuous drizzle (NOT Intermittent drizzle (NOT Continuous drizzle (NOT Rising then steady; Drizzle and rain, slight Drizzle and rain, moderate or heavy freezing) slight at time of freezing) slight at time of freezing) moderate at time freezing), moderate at time freezing), heavy at time of freeing), thick at time of Slight freezing drizzle Moderate or thick freezing drizzle or rising, then rising Wind speed in knots shown as feathers observatiion observation of observation of observation observation observation Predominate clouds of type in CH table. 1 more slowly ff on shaft of the wind direction arrow. CH

Rising steadily, or unsteadily 60 2 V V Visbility in miles and fractions. T T Air temperature in whole degrees. intemittent rain (NOT freezing) Continuous rain (NOT freezing) Intermittent rain (NOT freezing) Continuous rain (NOT freezing), Intermittent rain (NOT freezing), Continuous rain (NOT freeing), Falling or steady, then Slight freezing rain Moderate or heavy freezing rain Rain or drizzle and snow, slight Rain or drizzle and snow, moderate slight at time of observatiion slight at time of observation moderate at time of observation moderate at time of observation heavy at time of observation heavy at time of observation rising; or rising, then or heavy Present weather coded in figures found rising more quickly Characteristic of barograph as shown 3 in the “ww” table. Figures in blocks 00, ww a in the Pressure Tendency block. Steady, same as 01, 02, and 03 are not plotted. 3 hours ago 4 Past weather uses the symbols found in Pressure change in the 3 hours preceeding 70 Falling, then rising, Isolated starlike snow W pp Intermittent fall of snowfalkes, Continuous fall of , Intermittent fall of snowflakes, Continuous fall of snowflakes, Intermittent fall of snowflakes, Continuous fall of snowflakes, Granular snow (with or without (sleet, U.S. definition) the “W” block. Ice needles (with or without fog) (with or without fog) same or lower than the observation (28 = 2.8 millibars). sllight at time of observation slight at time of observation moderate at time of observation moderate at time of observation heavy at time of observation heavy at time of observation fog 3 hours ago Barometric pressure plotted in tens, 5 Amount of precipitation coded in inches Falling, then steady; or PPP units, and tenths of millibars. RR falling, then falling (189 = 1018.9 & 989 = 998.9 milibars) to the nearest hundredth. 80 6 more slowly Moderate or heavy shower(s) Slight shower(s) of hail, with Moderate or heavy rain Moderate or heavy shower(s) Moderate or heavy snow Slight shower(s) of soft or small Slight showers(s) of rain Slight snow shower(s) of soft or small hail with or or without rain or rain and snow Falling steadily, or Temperature of in whole Time precipitation began or ended. Code Slight rain showers(s) Violent rain shower(s) shower(s) shower(s) and snow mixed of rain and snow mized hail with or without rain, or rain without rain, or rain and mixed, not associated with unsteadily TT Rt and snow mixed degrees. not shown. snow mixed thunder 7 Steady or rising, then falling; or falling, Code for fraction of sky covered by low Symbols as used in USA. then falling more quickly Nh Moderate or heavy snow, or rain 8 or middle clouds. plotted in degrees , wind in knots, 90 Slight snow or rain and snow Moderate or heavy showers of Moderate or heavy rain at time of mixed or hail at time of and snow mixed or hail at time Slight or moderate thunderstorm, Heavy thunderstorm, without hail, Thunderstorm combined with Slight or moderate thunderstorm, Heavy thunderstorm with hail at visibility in miles, and pressure in millibars. hail, with or without rain or rain observation,;thunderstorm during observation: thunderstorm of observation, thunderstorm without hail, but with rain and/or but with rain and/or snow at time dust or sand storm at time Unused Slight rain at time of observation; with hail at time of observation time of observation and snow mixed, not associated thunderstorm during past hour, past hour, but NOT at time of during past hour, but NOT at during past hour, but NOT at snow at the time of observation of observation of observation Copyright 2013, Weather Briefing, L.C. www.weatherbriefing.com with thunder but NOT at time of observation observation time of observatiion time of observation 9