Forecast Discussions

I'm sure predicting the weather is a tough gig. It's a complex science, even with modern technology to help you out. Long-term predictions, especially, require a combination of experience, meteorological knowledge, and probably a bit of luck. This is where the computer models come into play, and although you won't hear your local forecaster say it, there are computer programs running constant simulations of incoming storm systems, and the simulations don't always agree. This is why I love reading the forecast discussions generated—in my area at least—twice a day by experienced meteorologists at my local NOAA weather headquarters.

Forecast discussions—simple, text-based advisories typed in caps—aren't intended for general public consumption; their cryptic language and terminology aren't easy to decipher by the layperson, and they often contain disheartening truths and expressions of doubt you won't hear on your local nightly newscast. This is what makes them so much fun.

Over time, you begin to realize that, not only do the computer simulations often contradict each other, they sometimes contradict themselves. Run a model once, and the storm system scheduled to arrive in 72 hours will create catastrophic weather conditions. Run the same model again, and now the system is 100 miles north, resulting in an entirely different and far more benign scenario. Sometimes you can almost see the meteorologists watching this chaos on their monitors and pulling out their hair by the fistful. And that doesn't even take into account the disagreement between the three or four different computer programs that might be attempting to make sense of the same storm system at the same time.

Here's an actual example from the recent past. If the local TV weather guy put things this way he'd probably be fired, but wouldn't it be refreshing to hear this kind of straightforward talk for a change?

AFTER A COUPLE OF RUNS WHERE THE GFS40 TOOK THE LOW CENTER MUCH FARTHER SOUTH ACROSS NORTHERN NEW MEXICO...THE 06Z TRACK IS A LITTLE FARTHER NORTH AGAIN...ACROSS THE SOUTHERN COLORADO BORDER...BUT NOT NEARLY AS FAR NORTH AS RUNS 24 HOURS AGO AT THIS TIME...WHICH HAD THE LOW CENTER TRACKING ACROSS WYOMING AS I RECALL. NEEDLESS TO SAY...THE EXACT TRACK REMAINS A MYSTERY. TO CONFUSE THE ISSUE MORE...THE 84HR NAM12 DIGS THE SYSTEM MUCH FARTHER SOUTH AND WEST OF COLORADO...ACROSS SOUTHERN CALIFORNIA AT 18Z SATURDAY COMPARED TO THE GFS40 POSITION OVER SOUTHWEST UTAH AT THE SAME TIME. THE 96HR 00Z ECMWF WOULD TEND TO SUPPORT THE GFS40...WITH ITS LOW POSITION NEAR THE 4 CORNERS REGION AT 00Z SUNDAY. SO...IMPORTANT QUESTIONS REMAIN UNANSWERED...BUT...ALAS...THE FORECAST MUST STILL GO OUT. SO...I`M STILL FAVORING THE GFS40 AT THIS POINT...WHICH BRINGS THE FIRST SURGE OF SHALLOW ARCTIC AIR INTO THE EASTERN PLAINS THURSDAY AFTERNOON AND THE 1ST ROUND OF PRECIPITATION INTO THE REGION ABOUT THE SAME TIME.

It's comical, but at the same time a little bit sad; you have to feel sorry for anyone whose job involves such a high level of doubt and frustration. All you can really do, I imagine, is give it your best shot based on currently available information, and hope for the best. Even when you're right and the storm warning you issued saves lives, your good judgment is quickly forgotten when the next warning results in nothing more than a dusting of snow. It's likely the public won't remember your meteorological good judgment, but every false alarm will be seen as further proof that you have absolutely no idea what you're doing. This is unfortunate, but probably unavoidable; predicting the weather has long been considered a reckless profession by many.

Personally, I don't think meteorologists get enough credit. I imagine it's a little bit like being an air-traffic controller: do your job right, and the only tangible result is another planeload of passengers arriving safely at their destination. Make a mistake, and . . . well, everyone will take note, but not in a positive way. In a similar way, the accurate weather forecast is taken for granted, but make a mistake and the blame pours down (forgive me) like rain.

Anyway, next time someone comments about another inaccurate forecast, you can point them to your local forecast discussion, wherein lies the evidence that things are not always as simple as they seem.