How Hot for Next Tuesday?

There's considerable forecast variability for next Tuesday's high temperature as of this Friday evening. Here's a recap based on information available as 6 p.m. Friday.

Wunderground BestForecast: 95

Weather.com: 89

Accuweather.com: 85

Weather.gov: 89

Wcco: 86

Kstp: 85

Kmsp: 87

Kare: 85

Strib: 80

Excessive Heat Watch—Dead on Arrival

It was hard not to notice that the NWS office of the Twin Cities stood tall with the issuance of an Excessive Heat Watch some 60 hours before the time it went into effect. On Monday evening, the NWS advised us that excessive heat levels might be reached during the day on Thursday. It may not have been an unprecedented amount of warning, but it’s not something we don’t see often. One would guess that the issuance of a watch so far in advance would suggest the likelihood of serious heat, but that does not appear to be the case based on the “regular” hot forecast in effect as of this writing (6 p.m. Wednesday)

Something seemed amiss about this watch from the start. When the watch went into effect the only counties within many miles (five states perhaps) of the Twin Cities were Hennepin and Ramsey. This suggested it was a marginal at best. And even while the forecast temps at that point were close to 100, the dew point forecast did not go above 60—hardly oppressive.

We understand that a watch does not always mean a warning will follow. But for the NWS to trumpet the heat watch so many hours in advance suggested a certainty and confidence that didn’t bear out. In the end, the NWS/Twin Cites looks a little silly.

Dubious Heat Advisories

In a season when heat advisories and excessive heat warnings are making regular appearances in Twin Cities forecasting lexicon, we’re starting to wonder whether they serve much purpose or at least question the proper use of them. A comparison of today’s weather with yesterday’s provides a good example.

On Monday, the Twin Cities was under a heat advisory. The temperature reached 98 degrees but the humidity was only moderate, and the heat index never reached advisory levels. And while it doesn’t figure in to the formal mathematical calculation of heat index, a persistent, gusty southwest wind made the heat more tolerable than it might otherwise have been.

In contrast, today’s high temperature reached 94 but the humidity was more oppressive. Toss in light and variable winds and it’s fair to say that most people would think today was more uncomfortable. The NWS did not issue a heat advisory and the heat index technically touched advisory levels (100). On June 27, a formal heat advisory was issued, yet the heat index never reached 100.

With the benefit of hindsight, an advisory (technically) should have been issued for Tuesday rather than Monday. And when you throw in the ill-advised heat advisory on June 27, that’s three days where the issuance/nonissuance of an advisory was wrong. To us, this merely points up the dubious nature of the formality of heat advisories in the first place. Throw in the oddly worded “excessive heat warning” and you’ve got even more confusion.

It’s simply very hot and uncomfortable weather! Nothing more, nothing less. In our minds, the advisories and warnings that occur in winter have far more relevance and significance to our daily lives. If the windchill is a gazillion degrees below zero and you take a long walk without being properly dressed, you’re going to suffer frostbite at a minimum and you could potentially freeze to death. If heavy snow arrives, particularly during rush hour, it’s going to mess with your commute and you might need to plan accordingly. But if the heat index one day is 100 and another day is 98, is that really much of a meaningful difference? And more importantly, is one day more worthy of a heat advisory than the other? We think not.

If you're curious to see official definitions for advisories, warnings, watches and the like for the Twin Cities, click here.

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One Hot Week

A hazy, smoke-enhanced sunset heralded the end of a 99-degree day in St. Paul.

Whether it's labeled with "excessive heat warning," "heat advisory," or merely "stinking hot," it's hot, headline-stealing hot. The only suspense, it would appear, is whether the mercury will hit the century mark this week.