"Massive Heat Wave" Off to Tepid Start

The 90 Run Has Yet to Begin
A funny thing happened on the way to that streak of 90s ... it hasn't yet begun. Despite universal forecasts of temperatures above 90 today, the temperature reached "only" 87. The highest heat index for the Twin Cities today was a not-off-the-charts 97. It seems questionable at best as to whether an excessive heat warning was really necessary.

The 80-81 degree dew point predicted by the Star Tribune weather columnist also never materialized. While the dew point did reach a tropical 77, it did not approach the record to near-record high dew point predicted in several recent Star Tribune blog posts.

A Forecasting Slump?
Perhaps you've noticed, but the weather gurus haven't been at the top of their game the last three days. The original prediction for heavy rain (to be measured in inches) was for Wednesday night into Thursday. Yet, Thursday saw only .13 inches of rain. The Friday forecast generally (and yes, we're generalizing about the forecasts) called for the chance of a few spotty storms and a high in the upper 80s. However, Friday saw the first bout of torrential rain (more than two inches) and a high of only 77. And as of Friday night, most forecasters called for only a small chance of rain overnight on Friday. In fact, more torrential rain fell in the early a.m. hours of Saturday. It all serves as another reminder that forecasting, particularly amid the chance of convective storms, is a tough task.

Weather.com Seems a Little Nuts
Weather.com is displaying an odd range of forecast temperatures for Sunday. It forecasts 96 for Minnetonka, 101 for St. Paul and 104 for Minneapolis, including the zip code for the Mpls/St. Paul airport. The official weather.com forecast is: Intervals of clouds and sunshine. Record high temperatures expected. Heat index near 120F. High 104F. Winds S at 10 to 20 mph.

Recapping the Original 7-Day Heat Wave Forecast
Here's an updated comparison of heat wave predictions made on Friday night to the actual temperatures reached so far. Note that all predictions for the first two days of the period have been well above actual.

File Under: Things That Don't Seem Logical

Here is a depiction of the latest heat watches and warnings. The red-shaded areas represent Excessive Heat Warnings; the lighter-colored shading represents Excessive Heat Watches. It makes some sense that the always-cooking urban core could be under a warning when surrounding areas are under watches. But what makes less sense to us is why there would be a warning for two counties (one in Minnesota, one in Wisconsin) that are midway between the Twin Cities in Duluth. Is the heat really expected to arrive in such an unusual arc pattern? Or is the thinking that the two counties didn't receive much rain today and thus will heat up faster? Hmm.... Professional meteorologists, what can you tell us?

Read It and Weep - Your Universal Heat Wave Forecast

Interestingly enough, the greatest amount of variability in the 7-day forecast is for today. Blue outline marks forecasts that (sort of) stand out as being cooler than others; red outline marks forecasts that stand out for heat. If you're not desiring a heat wave, you should be rooting for the Intellicast forecast, which "only" forecasts five consecutive days in the 90s.

The following information is based on forecasts collected this Friday morning.

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National Forecasters Outperforming Locals for This Week

Last Friday night, temperature trends varied by forecast outlet in a rather interesting way. Virtually all national forecasters (weather.com, accuweather and intellicast) saw the current week as being cooler than the local prognosticators. The national weather providers envisioned several days in the 70s, whereas the hometown studs maintained temps in the 80s throughout. Given the rather odd dichotomy in temps, we captured the forecast for later review. Our thinking -- our guess, really -- was that the locals would be better at forecasting local weather than the nationals. However, as this week has played out, and given the forecast for Thursday, that's not been the case. If you had your money on Weather.com, you were a winner.