Water, tropical, coastal and winter
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The water, tropical, coastal and winter categories, what a tropical cyclone asks of a spotter over two days, and the one rule about lightning that surprises people.
In this lesson you will
- List the reportable water categories and explain why offices publish so few numeric thresholds.
- Describe reportable tropical cyclone observations.
- State the coastal and winter categories relevant to this forecast area.
- State the rule for reporting lightning.
Your office asks about the hazards it gets
The categories below are the ones that appear on most offices' lists, but the weight on each is entirely local. A coastal office whose area includes bays, sounds and open water out to sixty nautical miles wants marine observations and surge depths. A High Plains office wants blizzard visibilities. An office over a burn scar wants debris flows. The same course, four different priorities.
| Where you are | What your office leans on you for |
|---|---|
| Gulf and Atlantic coast | Surge and inundation depth, marine observations, tropical rainfall totals, waterspouts |
| Southern Plains | Hail size above all, plus tornado and dust |
| Upper Midwest and Northeast | Snow and ice accumulation, ice storm loading, river and snowmelt flooding |
| Interior West and Southwest | Burn-scar debris flows, monsoon flash flooding, blowing dust, wind |
| Appalachians and steep terrain | Rapid-response stream flooding, landslides, ice |
| Anywhere urban | Street and poor-drainage flooding, which is under-reported almost everywhere |
Not an official taxonomy, and the boundaries are soft. The point is that the list your office publishes reflects what actually happens there, so the rare category on your page is the one worth reading twice.
Whatever is unusual where you live is the thing local spotters have least practice reporting, and it is often the thing the office most needs an observation of, because the surrounding network is not built for it either. Sleet in Alabama and a tornado in Oregon are the same problem. Read the category on your office's list that you have never used.
Water, quoted in full
Flooding: Report any flooding of roads, homes, or businesses.
Heavy Rain: Rainfall reports are always welcome, including rainfall
totals. Rain totals of more than 1 inch in an hour are also helpful.NWS Mobile/Pensacola, "Submit a Storm Report", read 11 September 2026. One office's water criteria, quoted in full because how little they say is the point.
No depth. No duration. No rainfall figure other than that one, and most offices are no more specific. "Any flooding of roads, homes, or businesses" is the whole criterion, and the one inch per hour sits under a different heading, describes rainfall rather than flooding, and is offered as helpful rather than required. Course material that fuses the two into a single national flood threshold has invented it. Module 6 lesson 5 goes through this in detail.
What to actually say is module 6 lesson 5 as well, and it comes down to four things: where the water is rather than where you are, how deep against a named reference like a curb or a tire, flowing or standing, and rising, steady or falling.
Tropical
A tropical cyclone is the one situation where a spotter may be observing for two days rather than twenty minutes, and where the most valuable observations are the plainest ones.
- Wind and damage, continuously rather than once. The peak is often not when you expect it, and the second half of a landfall arrives from the opposite direction.
- Surge and inundation depth, against fixed references. How far inland the water reached and where it stopped is a measurement somebody can survey against later.
- Rainfall totals, and the times you read them, since a storm-total figure without a window is hard to use.
- Pressure, if you have a calibrated barometer. Rarely available and disproportionately valuable when it is.
- Tornadoes. Tropical cyclones produce them, often well away from the center and on more than one day, and they are usually brief and rain-wrapped. Do not stop watching for rotation because it is a hurricane.
You will see total tornado counts attached to named storms. They are aggregated across many forecast areas and several days, and the count for any one area is often not published at all. Do not quote a number for your own county from a storm-wide total, and be aware that the preliminary and certified counts for a tropical system frequently disagree for months. Lesson 1 covered why.
Coastal
Coastal flooding and storm surge are separate categories in the record from rainfall flooding, and module 6 lesson 1 gives the definitions. For reporting, the useful distinction is the source of the water: rain that could not drain, or sea that came inland. Say which you believe it is, say why, and say if it is both, because where a coast is low and flat the two arrive together more often than not.
On some stretches of US coastline rip currents kill more people in a year than flooding, tornadoes, lightning and tropical systems combined. They are nonetheless a forecast and safety matter, not a spotter report item: there is no event to observe and time-stamp in the way this module means. Know the beach forecast and the flag system. Do not file rip currents as storm reports.
Winter, which does happen
Winter Weather: Any reports of snow, sleet, or freezing rain. Please
include accumulation information and reports of road conditions.NWS Mobile/Pensacola, "Submit a Storm Report", read 11 September 2026.
Rare here, and that is exactly the problem: rare events are reported by people who have never reported one. Three things carry most of the value. Which type it is, and freezing rain and sleet are genuinely different and behave differently on a road. How much, measured on something flat and open rather than on grass or a car hood. And what the roads are doing, which is the part emergency management acts on within the hour.
Lightning, and the rule that surprises people
Lightning is reportable when it causes damage or injury, and not otherwise. A tree split, a house fire started, a transformer destroyed, somebody hurt. Not "a lot of lightning", not close strikes, not an impressive display. The detection networks already see every flash; what they cannot see is what it hit.
Check yourself
Which of these is a reportable observation to the local forecast office?
- A lightning strike that set a house roof on fire
- Frequent cloud-to-ground lightning, roughly one strike a second
- A red flag flying at the beach for a high rip current risk
- A forecast of four inches of rain overnight
- Half an inch of rain in an hour
Hint
One category is reportable only by its consequences, and two of these are not observations at all.
Answer
A lightning strike that set a house roof on fire
Lightning is reported when it causes damage or injury. Flash rate is already measured by the detection networks. A beach flag is a forecast product rather than an observation, a forecast is not a report of anything that happened, and half an inch in an hour is below the one inch the office singles out as helpful, though rainfall totals are always welcome.
Sources
- NWS Mobile/Pensacola, "Submit a Storm Report"
- NWS Instruction 10-1605, Storm Data preparation (current edition 26 July 2021)
- NWS Weather Spotter's Field Guide
- NWS Mobile/Pensacola, about our office and county warning area
- NWS Mobile/Pensacola, measuring winter precipitation