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Joe’s Weather Blog: October In July! (THU-7/10)

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Well the rain skirted by the KC area…we have clouds this AM but the sun will be out later in full force and things are going to heat up quite a bit into the beginning of the weekend.

Forecast:

Rest of today…becoming sunny and a bit warmer with highs approaching 85°.

Tonight: Partly cloudy with perhaps some scattered storms possible but we should be OK for the evening (at least), higher chances may be more towards north-central MO and NE MO. Lows in the 60s.

Tomorrow: Hot and more humid with highs near 90°

Discussion:

I’ve written extensively this week about the coming shot of unusual cool weather for July in the middle of the next week and I’ve talked about the potential of record low temperatures for several days…that is all very much still on the table as previous blogs have mentioned.

I thought today I’d talk about this coming October-ish airmass in more historical context. For the vast majority of the people out there, when we refer to record lows…we always talk about what is going on at the surface. Fair enough…

You know me however, I always strive to dig deeper and talk about things with a eye towards the bigger picture…so today I went digging through years of upper air balloon soundings to find the chilliest airmasses in July above the surface to put next weeks cool airmass into more perspective. In other words I wanted to see how the airmass that is forecasted to come next week compares aloft (at 5000′ or so) to previous cold outbreaks in July utilizing the balloon launches at the NWS in Topeka (our closest upper air sounding station).

Here is what I’ve come up with…

Right now the forecast off the EURO model for next weeks peak of the cool airmass is for temperatures at about 5000′ (or the 850 millibar level in the atmosphere) to be around a +8°C. This would be within 1°C of the coldest temperatures ever recorded by a balloon observation at the NWS in Topeka in the month of July. The coldest ever record in July is a +7° back on 7/13/1990. So then I looked at our morning lows around that time frame…on the 13th it was 58° on the 14th it was 54° and on the 15th it was 56°. I have no idea what the dewpoints were like or whether or not clouds played a role in the temperatures on those mornings or not….

The next coldest was 1972 (still a +7° at 5000′ or thereabouts) on 7//5. That morning we dropped to 52° at the surface here in the KC area. Then came 1971 from the 29th-31st (with a +7°-+9C at 5000′) and we dropped to 59°/52°/56°. Other cold shots with a +8°C at 5000′ (our EURO forecast at this point) were in 1970, 1967. In all cases lows were at least in the mid 50s (if not lower).

So at this point, by looking at the history of what has happened before to make a higher confidence forecast of what can happen in the coming future (next week) one can reasonably forecast lows of 52-57° for a couple of mornings…again those would be near or record breaking lows for those individual mornings at the surface. Many meteorologists just look at models and take what they spit out verbatim…this is a chronic issue with some of the “new kids” on the block. Some, not all though, to be fair. Some of my colleagues and I talk about this a lot. They just don’t get that involved with this stuff in school like they should now-a-days. The models are getting vastly better but sometimes with historical things it’s helpful to see what’s happened in past to forecast the future…but I digress.

The bottom line is IF this coming airmass has a 5000′ temperature of lower than +7C or about 44.6°F at that level…it will be the coldest JULY airmass in this area in our weather history of balloon launches.

Some additional perspective back on the surface…now with the coldest July HIGH temperatures in KC weather history going back to the 1880s or so.

ScreenHunter_07 Jul. 09 09.36

What about the coldest July LOW temperatures…here is that data as well. Then benchmark is 51° set back on 7/5/1997. Last week we dropped to 53° (5000′ temperature was a +11°).

ScreenHunter_08 Jul. 09 09.36

 

Would I be surprised if we get down into the 40s one of those days next week..no. It’ll be tough though because the nights are short during this time of the year. N MO dropped into the 40s last week in spots…then again with all the development by the airport over the last 10-25 years it also makes it tougher to get low temperatures to crater as much now as it did in the past.

One note…some of the other extremes for this type of coming airmass for next week were again back in the early 70s. 1) remember those winters (nasty) and also those surface low temperatures were for downtown KC. KCI wasn’t the official station yet for KC until November of 1972 I think. Interesting side-note I think.

Tomorrow I may blog about those colder July airmasses and see IF I can find some connections to the following winter…we’ll see about that. I do what happened in July of 2009 and then the following winter though…and for those that hate winter…you can stop reading now.

Joe

 

 

 

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5 comments

  • Patrick Trudel (@sedsinkc)

    This is a great blog for weather history enthusiasts like myself. Your data re historical July 850 mb balloon data is pure weather gold. Re your list of coldest July high temperatures, it helps to keep in mind that many of the chilliest days in July are associated with rainfall. While the coldest high on record for July is 64, the coldest high on record for July on a day with no measurable rainfall is 68 on July 2, 1924. I assume it’s too early to know whether next week’s cool spell will be completely dry, or if the air aloft will be so cold that it generates some convective showers during the daytime?

    • Joe Lauria

      The high res EURO does take our 850 temps down to a +7° which if true would place this in the Top 3 or 4…and we’re talking about 1/10ths of degrees as a difference. My thought would be dry after TUE…unless there is some weird vort max that drops that I can’t see at this point. ^JL

  • Farmgirl

    I am not surprised at this “cool” snap for August. Since we have had mutliple cold air bursts or blasts in winter, this just seems to be the norm for this years weather pattern. I hoping we do not have another long cold duration like last winter as it was brutal…my heat pump automatically shut down due to dropping to 5 degress which it is programmed to do. I will take this cool burst of air to give livestock a break from the humidity.

  • Jeff

    I was camping in 1971 or 1972 in July and it was cold. We had taken summer clothes and at that point weather forecasting was not as good as today. We did not even know or did the weather people that it was coming.

  • Amae

    July 4-5 1972 we lived in rural area….Franklin county. Our daughters 1st BD was July 5. We were outside setting off fireworks the night of Jluy 4. We had COATS on ! We were living in an old farmhouse that had a very small living room with a propane gas stove for heat. My husband had taken the stove out to the shed weeks before to make more room in the living room (we had 3 children). And on July 4-5 we had to really pile on the blankets to keep warm. It was for sure a dramatic cool-down for July.

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