- 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 Reviewed and, after you actually issue the LSR, LSR issued. 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.
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.
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.
Review log and copy
Checks are stored on this browser, keyed to the source, station, metric, sensor, timestamp, and unrounded value. A new extreme gets a new check. Example and real reports have separate identities. Use Review log to export or import a JSON log. Checks are not shared among office computers. The copied text is an LSR narrative draft, not a complete coded product and not a transmission to AWIPS.
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.