The National Weather Service has issued Red Flag Warnings due to low humidity and gusty winds in areas of Colorado, Montana, and North Dakota for Sunday. Most of the warnings expire Wednesday evening.
In southwest Colorado similar conditions could persist into Monday .
(Red Flag Warnings can be modified throughout the day as NWS offices around the country update and revise their weather forecasts.)
x
x
Why do the warnings abruptly stop at state/country borders?
Kiki, it’s a good question. Red Flag Warnings are designated for pre-defined Fire Weather Zones. Most states have dozens of them and usually the Zones do not cross state lines. Sometimes different National Weather System offices are responsible for forecasts on each side of a state border. And, the criteria or thresholds to qualify for a RFW may be different across the state border. Some forecasters could be more aware of fire danger, or maybe it simply did not occur to them to designate a RFW. A couple of years ago RFWs rarely appeared in Utah for some reason even when they were surrounded by them, but that has changed a bit in the last year or so.
But having said that, it is confusing when the weather forecast is confined along straight imaginary state lines. It makes it look rather arbitrary and untrustworthy, even though there could be several reasons (good or bad) why these straight lines appear in a graphical weather forecast.
Regarding country borders, the U.S. and Canadian forecasters do not make forecasts across the border, and there is apparently no system or protocol for importing forecasts across the border so they will appear in a buffer zone on each country’s maps. In addition, the two countries use fire weather forecasting systems that are very different.