- Connect your Synoptic token or office proxy. Pick a time window and a variable.
- Select a map value, ranked report, or table value. The details pane shows the exact observation time, sensor, station type, and location.
- Inspect the sensor and surrounding reports. Edit the narrative if needed, then use Copy LSR text.
- Check Checked and, after you actually issue the LSR, LSRd. Copying does not issue or mark a report.
Rolling extremes, not calendar days
12h means observations whose timestamps fall within the last 12 hours ending at the displayed window end. We use Synoptic time-series observations rather than calendar-day statistics. “Current” uses the latest value per variable inside the selected freshness limit. Different variables may have different timestamps. Equal extremes use the latest matching time.
The lowest numbered available sensor is preferred; a reported sensor precedes a derived sensor with the same number. We keep one reporting series per variable rather than combine different sensor heights. The source sensor and sample count appear in the details. A missing reading is never treated as zero. Coverage gaps can hide a true extreme. Times are observation or report timestamps; a delayed report or interval summary may describe an earlier event. Confirm event timing before issuing.
Reading an observation history
Numeric station details include a value axis with units and five time labels. Tap or hover over the chart for the nearest actual report, or use the arrow buttons and keyboard arrow keys to step through readings. The readout includes the full date, time, and displayed time zone. Selected report returns to the maximum, minimum, or latest observation that opened the details. Inspecting the chart does not change that report, its LSR draft, or its review marks.
Dates and time-zone abbreviations below the axis clarify overnight windows and daylight-saving changes. Long gaps are not joined. A hollow visibility point represents a reported bound such as <0.25 mile, rather than an exact distance. One available report shows a point, not an invented trend. Precipitation totals and individual snow reports retain their report-period details.
Geography and metadata
All 37 IWX counties and nearshore zones LMZ043 and LMZ046 use bundled NOAA/NWS polygons. Coordinates are checked against those polygons; marine zones take precedence where county and water boundaries overlap. A station outside the area is discarded. County names come from the boundaries. The nearest place is the closest U.S. Census incorporated-place or CDP reference point, with distance and direction; it is not a street address.
Synoptic’s network registry supplies station types. The ASOS/AWOS network combines both types; we label it ASOS / AWOS unless the provider explicitly identifies a subtype. Unknown metadata stays unknown. Elevation is the station elevation, not sensor height.
Quality control and calculated values
Synoptic basic QC is requested with flagged data removed. This is an automated screen, not manual verification. Available wind-chill and heat-index reports are used first. Missing values may be calculated from temperature and sustained wind, or temperature and humidity, at the same timestamp. Wind gusts are not used to calculate wind chill. Local wind chill is calculated only at or below 50°F with wind above 3 mph; local heat index is shown only for applicable hot conditions at or above 80°F. A calculated value is labeled in the details and narrative.
Present weather
Present weather uses METAR weather text where available, with Synoptic weather-number decoding and condition text as fallbacks. Red: FZRA or heavy snow (+SN). Orange: snow (SN) or unknown precipitation (UP). Yellow: light snow (−SN) or heavy thunderstorms (+TS). The strongest matching category wins in a mixed report. Blowing snow, freezing fog, and vicinity reports are kept distinct from falling snow or freezing rain.
Each station shows its latest weather report inside your selected window, rather than the strongest earlier report. A 12-hour search can still contain an old weather report; inspect its timestamp or select Current. An old report is labeled when it exceeds the Current freshness limit. Missing or zero weather codes do not establish clear conditions; cloud summaries are not used as present weather.
Reported precipitation rate
Precipitation rate is the reported Synoptic precipitation_rate field, converted from an explicitly labeled rate unit to inches per hour. It is not computed by dividing a precipitation total by time. Current shows the latest rate; rolling windows show the largest reported rate. The rate may include precipitation water equivalent and is not a snowfall-depth rate.
Rate requests are separate. Synoptic basic QC remains on, and QC-flagged rates are retained with a visible verification badge, map exclamation mark, and warning in the LSR draft. The published Synoptic range-check table can flag intense rates; a QC flag does not by itself establish invalid data. Sample-level flags, station-only flags, and missing QC status are distinguished in the details. Other weather variables continue to remove QC-flagged observations.
Precipitation totals
Max precipitation ranks the largest available station accumulation for your selected window, in inches. Current uses the previous one hour, independent of the freshness setting for other variables. Synoptic’s Precipitation service selects a representative precipitation variable and handles gauge resets and differing reporting intervals. We never add overlapping hourly, daily, or running gauge totals. This is precipitation water equivalent, not snowfall depth.
The details, station table, CSV, and LSR draft preserve the actual first and last report times. Those times may differ from the requested window when reports are infrequent or missing. A station total does not guarantee complete coverage of the window. Missing totals stay missing; valid reported zero totals remain zero. A failure of the precipitation service is shown explicitly and does not hide other successful observations.
Snow reports
24h snowfall means a reported 24-hour accumulation, with its report timestamp inside your selected window. It is not a total for a 6h or 12h selection. Snow depth is snow on the ground, not new snowfall. The Snow reports tab also lists “since 7 AM local” and reports without a supplied period. We never sum overlapping snow reports or infer snowfall from a depth change. Unknown-duration reports require period confirmation before use.
Shared Checked and LSRd overviews
Checking Checked saves the exact observation to the Checked tab. Checking LSRd records that staff already issued the report through their normal workflow. Neither copying text nor checking a box issues a product. These statuses are independent.
Each status stays for 36 hours from its first selection, then disappears. Page refreshes and repeated active checks do not extend the clock. The two tabs retain the original value, station metadata, observation time, narrative draft, optional staff initials, mark time, and expiration, even after the live observation window changes. Remove a mark from its tab to clear only that status.
With the office connection, the lists use the shared database and refresh every 30 seconds while this page is visible. Staff need the same production office site and a valid office sign-in; no separate individual login is added. Initials are optional self-entered labels. If shared storage is missing or unavailable, the app reports the failure and does not pretend a browser-only check was shared.
Standalone HTML, direct-token sessions, and examples use clearly labeled browser-only lists. The old Review log is preserved as a browser archive. Export/import there affects that archive, not the shared lists. Use Export CSV on Checked or LSRd to save the active list.
Unit recovery and blank counties
The app converts explicitly labeled measurements to Fahrenheit, mph, miles, and inches. If a unit is missing or unsupported, affected stations receive one standard metric-unit retry. Valid, simultaneous temperature and sustained-wind or humidity inputs can restore a wind chill or heat index. The Loaded datasets view separates values recovered with labels, calculated indices, reports outside the formula range, and values still excluded. Only unresolved readings generate a unit warning; the app never guesses Fahrenheit.
More variables and station colors
View more variables expands Fahrenheit temperature extremes, maximum sustained wind speed, minimum visibility in miles, and snow depth. The selected observation window applies to all of them; Current shows the latest eligible reading. Sustained wind and gusts remain separate. Visibility codes are not interpreted as distance readings.
The Stations view has a threshold legend. Labels turn yellow, orange, or red according to your selected thresholds; the strongest matching color wins at the displayed precision. Marine rules apply inside the assigned marine zones or to marine observing platforms / networks. Land visibility is yellow above 0.25 through 1 mile, orange at exactly 0.25 mile, and red below 0.25 mile. A less-than-quarter report stays labeled <0.25 and uses red. Marine visibility thresholds are unchanged. Snow amounts and precipitation totals have no threshold highlight; reported precipitation rates use 2 / 2.5 / 3 in/hr for yellow / orange / red.
The station map keeps locations without the selected variable visible: gray dots have other dashboard readings; hollow dots have metadata only. Select a dot to see available readings. The county and dataset tables separate stations listed, stations with any dashboard readings, and stations with the selected variable. A blank gust report does not mean there are no weather stations in that county. With a review filter selected, stations without a selected observation are hidden because there is no observation to review.
Sources and coverage
The Sources tab lists supported network groups and shows the exact networks returned inside IWX after connection. A station can be listed in the inventory without reporting the selected variable. A network name by itself does not prove that a gauge is a buoy rather than a coastal station, or an ASOS rather than an AWOS. We preserve provider metadata and mark mixed types explicitly. The feed requests all networks without restricting station discovery to particular variables. This includes precipitation-only stations and unfamiliar local networks. Every returned network appears in the inventory and filters, even if no station has usable readings for the selected variable. Any accessible Tempest stations are included with WeatherFlow in the main feed.
Office sign-in
On this Cloudflare site, enter the office access key once to stay signed in on the same browser for 24 hours. Reopening automatically loads live observations. The expiry runs from sign-in and is not extended by refreshing. Sign out clears remembered access. Browser cookies must be allowed; clearing cookies or ending a private browsing session may sign you out sooner. Your office key and Synoptic token are never saved in local storage.
Hosting and access
The HTML needs no PHP or build step to run. The Cloudflare Pages upload includes the secure office API. Account and token permissions still determine which observations Synoptic returns. Requests are sent one at a time to accommodate NOAA accounts with a concurrency limit of one. Your CMS must allow JavaScript and its data requests.
Source documentation
Boundary and Census reference data retrieved October 22, 2026 (ET). Static boundaries should be refreshed when NWS responsibilities change.