{
  "source": {
    "kind": "Measured and described",
    "title": "U.S. Department of Agriculture, Weather Bureau, Weather Map, 14 May 1892, 8 A.M.",
    "url": "https://library.oarcloud.noaa.gov/docs.lib/htdocs/rescue/dwm/1892/18920514.pdf",
    "page": 1,
    "sha256": "6a94d2d852078c5bbe089e32a14b47e4beb9e24d90aecd9e872f8930d7856ea6",
    "catalogue_url": "https://library.noaa.gov/weather-climate/daily-weather-maps",
    "rights": "Federal Weather Bureau publication, public domain; NWS reuse policy https://www.weather.gov/disclaimer",
    "read_date": "2026-09-18"
  },
  "time": {
    "date": "1892-05-14",
    "printed_hour": "8 A.M.",
    "legend_verbatim": "Observations taken at 8 A.M. and 8 P.M. 75th Meridian Time.",
    "utc": "1892-05-14T13:00:00Z",
    "note": "75th-meridian time is UTC-5, the Eastern Standard Time convention used here."
  },
  "station": {
    "printed_name": "Block Island, R. I.",
    "nearest_status": "Nearest station identified on the opened morning map; not an exhaustive claim about surviving archives",
    "approximate_distance_km": 35,
    "distance_receipt": "solar.json",
    "historical_instrument_coordinates": null,
    "coordinate_reason": "1892 instrument location not verified; approximate distance uses later NOAA Block Island coordinates as a geographic proxy"
  },
  "row_verbatim_cells": {
    "Pressure. Readings in inches.": "30.44",
    "Pressure. Change in 12 hours.": "+ 8",
    "Temperature. Of air, degrees Fahrenheit.": "44",
    "Temperature. Change in 24 hours.": "− 4",
    "Temperature. Minimum.": "42",
    "Wind-velocity, in miles per hour.": "8",
    "Rainfall, past 24 hours, inches.": "0"
  },
  "used_values": {
    "air_temperature_f": 44,
    "wind_speed_mph": 8,
    "rainfall_preceding_24h_in": 0,
    "minimum_temperature_f": 42,
    "pressure_inhg": 30.44,
    "pressure_change_12h_inhg": 0.08
  },
  "mapped_description": {
    "sky": "Cloudless",
    "basis": "In the unmodified 8x page-1 clip, the symbol left of the faint Block Is label and northwest of HIGH has an open ring, like Nantucket. Boston has a bar across its ring. Comparison with the legend identifies the open ring as Cloudless.",
    "confidence": "Open ring confirmed at 8x against neighboring stations and the legend; a descriptive category, not a cloud measurement.",
    "wind_direction": null,
    "wind_direction_reason": "Not established: the barbed end cannot securely be identified as head or fletching from the legend. No direction inferred; the printed 8 mph remains.",
    "high_pressure_label_verbatim": "HIGH",
    "high_pressure_label_location": "Southeast of Block Island, marking the high-pressure centre off that coast on this map.",
    "symbol_receipt": {
      "url": "/data/perry-stonington-1892/map-wind-detail.png",
      "source_page": 1,
      "render_scale": 8,
      "clip_fraction_of_page": [
        0.745,
        0.345,
        0.825,
        0.43
      ],
      "clip_points": [
        1055.0987927246094,
        389.90521179199214,
        1168.3979919433593,
        485.9688146972656
      ],
      "caption": "Block Island symbol and the coastal HIGH label, unmodified 8x rendering; no wind direction claimed."
    },
    "comparison_receipt": "/data/perry-stonington-1892/map-northeast.png",
    "legend_receipt": "/data/perry-stonington-1892/map-symbol-legend.png",
    "correction": "The first build and first repair misidentified the station in the source crops. Their symbol readings are withdrawn; the table transcription is unchanged."
  },
  "regional_text_verbatim": "The clearing condition has moved from West Virginia to the north Atlantic coast. A ridge of high pressure stretches from this clearing condition to Manitoba.",
  "limits": [
    "No Stonington observation at 5 a.m. located.",
    "The map is three hours later if the title uses Eastern Standard Time, or about three hours twelve minutes later if it uses Stonington local mean time.",
    "Zero in a 24-hour rainfall column does not establish dry conditions at Stonington at 5 a.m.",
    "Neither the regional description nor the station symbol describes the painting."
  ],
  "column_interpretations": {
    "minimum_temperature_f": {
      "heading_verbatim": "Temperature. Minimum.",
      "cell_verbatim": "42",
      "unit": "degrees Fahrenheit, as identified by the temperature group",
      "qualification": "Minimum reported on the 8 a.m. map; the heading does not explicitly state its observation interval. Page wording does not assert an exact overnight interval."
    },
    "pressure_inhg": {
      "heading_verbatim": "Pressure. Readings in inches.",
      "cell_verbatim": "30.44",
      "unit": "inches of mercury",
      "reduction": "Map legend specifies reduction to sea level and 32°F."
    },
    "pressure_change_12h_inhg": {
      "heading_verbatim": "Pressure. Change in 12 hours.",
      "cell_verbatim": "+ 8",
      "unit": "hundredths of an inch of mercury in the printed change column",
      "conversion": "8 / 100 = +0.08 inch",
      "unit_verification": "The 13 May 8 p.m. map prints 30.36 inches at Block Island; the 14 May 8 a.m. map prints 30.44. Their 12-hour difference is +0.08 inch, confirming the scale of the printed +8. The change heading itself does not spell out hundredths."
    }
  },
  "pressure_previous_observation": {
    "title": "Weather Map, 13 May 1892, 8 P.M.",
    "url": "https://library.oarcloud.noaa.gov/docs.lib/htdocs/rescue/dwm/1892/18920513.pdf",
    "page": 2,
    "sha256": "4437b12d268903836f07e3207494dc855ac175dfde6ca7229220bf10d25ff489",
    "station": "Block Island, R. I.",
    "heading_verbatim": "Pressure. Readings in inches.",
    "cell_verbatim": "30.36",
    "time": "1892-05-14T01:00:00Z",
    "role": "Independent check of the morning map pressure-change scale; not substituted for a 5 a.m. observation."
  }
}