Perhaps more than any other day of the year, the Fourth of July is when Americans most rely on the weather forecast.
Earlier this week, Washingtonians looked to their favorite weather predictors for the forecast. My go to is the "Capital Weather Gang," the official site for The Washington Post, and a blog whose team of meteorologists provide the forecast for WAMU 88.5 and have earned a loyal following and a lot of respect.
On Tuesday, they wrote.
The July 4 outlook looks nicer with mostly sunny skies, low humidity and highs in the comfortable low to middle 80s. Confidence: Low-Medium
I’m a weather geek, so each day I also sit down and checked out the local TV stations. Mid week, everyone, including CWG, was saying, low to mid 80s with a chance of thunderstorms. For those of you not familiar with summers here, that’s almost a generic forecast. Most folks don’t cancel their plans. The storms are hit and miss and events like the Nationals games usually get in with no or small delays.
Yesterday afternoon, the forecast for Monday changed dramatically. The Capital Weather Gang wrote:
The Independence Day forecast has taken an ominous turn, and showers and storms are increasingly likely, especially during the afternoon and/or evening.
In its extended forecast discussion, the National Weather Service is now highlighting a “heavy rainfall threat” from the central Appalachians to the Mid-Atlantic on July 4. The GFS model… drenches the region with 1 to 2 inches of rain.
In light of what some might call a predication fiasco, it’s tempting to hammer the forecasters. Personally, I’m not going that route. In fact, we should point out that weather forecasting, never an easy thing, has come a long way. Using massive data not available during our father’s and mother’s time, the meteorologists do a good job with forecasting. For example, here in Washington, the Capital Weather Gang pretty much nailed the last handful of snow storms.
Even with all that computing power, radar and satellites, meteorologists agree that weather forecasts beyond three to five days are unreliable. That’s why CWG footnote their forecasts with confidence levels - low, medium, high.
Of course, that doesn’t mean they and other weather blogs have refrained from posting about what’s possible beyond five days and making a seven day forecast. Weather geeks love the models, the charts and the discussions and many times the forecasts hold up. Summer is generally easier, while springtime can cause premature balding.
In contrast to the practice of seven day forecasts, the local weather meteorologists have generally refrained from looking beyond five days, at least when they show the graphic. That integrity wall, however, is about to fall. NBC4 rolled out their “exclusive” ten day forecast this week, and you can bet your paycheck the other stations will follow.
We live in a fast paced world, so this particular watershed moment in the forecasting timeline will hardly be noticed. And maybe it isn’t a big deal.
But planner, beware. The weather can be a strange beast. Keep those grains of salt handy…