Tuesday, July 12, 2011

Summer in the City: All Forecasters Predict Major Heat Wave

Start getting ready to hear the heat wave classics on the radio ... according to virtually all weather forecasters in the Twin Cities, a major heat wave is expected to arrive by the end of the week. For Sunday, no forecaster is going lower than 95. At this point, KSTP is most bullish on a persistent heat wave, forecasting a high of 98 next Tuesday. As of Tuesday evening, here's how both the local and national weather outlets saw the steamy forecast (Strib forecast is as of Tuesday morning):


Update: As of Wednesday night, here's how forecasters saw the upcoming heat wave (Saturday through Wednesday). Note that KSTP, as it often seems to be, forecasts the highest temperatures, with an average heat wave temperature of 97.4 for the five-day period.


19 comments:

  1. This will absolutely happen. And the dew points will be very high too. Expect heat advisories/warnings to be issued with this heat wave, no question.

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  2. very interesting indeed....I just took a look at the Euro 0z run (7pm Tues) and calculated the heat index each 6 hours....if that solution is correct expect heat index readings of above 90° for 120 hours straight. It starts on Sat and goes thru Fri morning. The GFS is not as bullish although heat index's should be around 110 sunday thru Tues and 100 on wed, it's not as bullish with the high temps during the day, they should top out in the low 90's instead of the Euro's upper 90's, thus the GFS lowers the heat index into the 80's each night. Either way next week will be nasty.

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  3. Yuck. Yuck yuck yuck. I'm going to need to take out a loan to pay my July electric bill.

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  4. The Question is, when will it end? This wave could go beyond the forcasting range of all the forecasters.

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  5. If the Euro is correct it should break on Fri morning the 12 0z run showed temps at 1pm at 82 with dew point at 58 or so

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  6. Given that forecasting is far less accurate, can we really be sure that this heat will last as long as many thing it will? Climatologically, it seems we just don't get that many long streaks of 90+ in these parts.

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  7. On that note, when was our last stretch of more than 5 days above 90?

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  8. Bill you are correct, just showing what the Eruo and GFS says what may happen, if you want to escape the heat the north shore would be a option, but not a good one as thunder is possible up there almost every day next week....so no where to go.

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  9. Yuck is right couldn't agree more AB,to answer your question July 2005 was the last time we had a heat wave of 90+ of at least 5 days,in fact it lasted 9 days. And for the record the longest heat wave recorded at MSP was July 5-18,1936,that's right 14 grueling days above 90(happy I wasn't alive for that) .I guess my wife's saying of Minnesota only having two seasons(winter and summer)is coming true this year with our extra long winter and now the dog days of summer

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  10. Ok now for the good news. It appears as if all the models are starting to come around to the Euro's way of thinking (the euro has been showing this for about 3 days). It looks like we will get a good soaking before the heat takes hold. This the latest model output I can find for precip.

    Nam 1.87"
    SREF 1.26
    Euro about 1.75
    GEM betweein 1.75 and 2.00

    so where is the GFS? sitting on the side lines at .65

    Flood watch is for sure warranted, some area's may pick up more than what is forecast depending on where the stronger T-storms set up at.

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  11. Why would a lot of rain before a heat wave sets in be good news? All that will do is exacerbate the boundary layer humidity (which will already be high enough due to envirotranspiration as crops are approaching maturity). So this "good" rain will end up pumping a bunch of moisture into the boundary, trapped under the high/capping inversion and sending heat indices even higher!

    Forecasting when the heat will "break" is difficult when you're looking 5-8 days out. One of those nights could see a big MCS come crashing through and really take a bite out of the heat. The GFS is clearly showing that this heat wave will peak Sun-Tue, with widespread max heat indices of 105-115 (isolated areas up to 125). Decreasing temperatures (but still hot) through probably the following weekend, but with the intensity of the high decreasing and the baroclinc zone sinking southward the threat for thunderstorms/MCSs will be increasing by Thu/Fri/Sat.

    NOAA/HPC provides peak heat index forecasts as well as probabilities, nice tool to look at.

    http://www.hpc.ncep.noaa.gov/heat_index.shtml

    Peak HI for MSP during the heat wave (according to HPC) is right near 110 Sun-Tue.

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  12. @P

    with as much sand as we have up here and the ridiculously strict watering restrictions, my lawn may survive with minimal watering, at least I hope so

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  13. 14 6z gfs now shows a apparent temp approaching 118 on Tues.

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  14. randy; model data is not a forecast, model output "cut and paste" is NOT forecasting. airport picked up 0.13". brutal dude.

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  15. local mets blow another one(.13 inches of rain)when everyone of them called for 1-2inches,if this was winter can you say bust. Now on to the heatwave coming(which sucks) with all these hot temps and dew points being thrown around as high as 80 degrees and heat indexes as high as 115,I went to see some records and see if our upcoming heatwave can break some records.Highest dew point reading ever recorded at MSP WAS 81(7/30/1999)and highest heat index for the state of MN(125-Pipestone)see what happens!

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  16. The 'overnight rain' forecasted by the NWS and MR. Barlow last night is getting going at about now,not exactly overnight since it's almost 9am,but better late then never I guess,storms looking bit ominous

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  17. @Anon from 9:01 pm

    Did I say any thing about forecasting??? looks to me that I was just showing what the model out put saw. If you want to call that "cut and paste" so be it, that was exactly the meaning behind that post, sorry if I offended you. And further more I did not put a time frame on it, I just said before the heat kicked in.

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  18. @Randy

    That is what Paul Douglas does habitually on his blog. Maybe that is alright for a blog, but why show all these different model outputs? To show the forecast envelope you're given and provide yourself some cover for if/when your forecast heads south? His job should be to interpret all those data and distill them into a single forecast for his readers. If he wants to provide an error range, then he should just do that (which honestly would be a great service for forecasts - give people not just a single value but a range of forecast temperatures with emphasis on your mid-point).

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  19. who would have thought, I had 4.4" here in a 24 hr period ending at 830am on 7/16, no one saw that much

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