[Posted Jul 23, 2024]
How was that title? I’ve been practicing for AccuWeather-level post titles and I’m pretty sure this title was worthy of that title. Okay, too many titles. Since this is probably going to be my longest post yet, I’m going to divide it up into four sections, plus an introduction and a conclusion; so I’m basically making an essay.
Our heat wave is coming to an end with some cool temperatures and a little precipitation. Here’s the forecast:
PART 1 – What is causing the temperature drop?
To see the beginning of this cooldown, we have to look at now. Opening good ol’ trusty Windy.com, we can see the rarely-seen-here work of the northern equatorial jet stream. The current layout is so hard to explain I’m just going to enter in an edited screenshot to help me and you out.
A. The two jet streams break apart around central Siberia.
B. The isolines are hard to see, but there is an “indent primarily upper-level low” there. That low is pushing the equatorial jet stream to the east, instead of just straight northeast.
C. The equatorial jet stream zooms back to the west, and then heads north to connect with the main jet stream before going back south to the Great Lakes, making a heat dome over areas of Yukon, Northwest Territories, Alberta, and Saskatchewan.
Our cooldown happens when the upper-level low heads over to Alberta, and then once it’s over the mountains, it transitions into a more lower-level low, and becomes very strong. It will break off from the equatorial jet stream around Thursday night, transforming it into a solitary low. The pressure then will be around 990 hPa. It will move off once we start the weekend, so we will see the end of the cold wave around Saturday or Sunday.
PART 2 – What is the temperature forecast?
It’s table time!
| EC | AW | TWN | Forecast | |
| Tuesday day | 30 | 31 | 30 | 30 or 31 |
| Tuesday night | 17 | 16 | 18 | Near 17 |
| Wednesday day | 21 | 26 | 26 | Mid 20s, maybe low 20s |
| Wednesday night | 17 | 16 | 17 | 16 or 17 |
| Thursday day | 19 | 21 | 22 | Near 20 |
| Thursday night | 12 | 13 | 13 | 13 |
| Friday day | 19 | 20 | 21 | Near 20 |
| Friday night | 15 | 13 | 15 | Near 14 |
| Saturday day | 23 | 26 | 25 | Mid 20s |
PART 3 – What is causing the precipitation?
The low of course, that’s how lows work. The main three models that are here and are long term – GFS, ICON, and ECMWF all say pretty much the same thing, except for GFS of course. It’s trash at forecasting clouds and precipitation. They both say that we will be getting the edge of a system expected to move through to the northwest of us, and they both say we’ll be getting the most precipitation on Friday. This really only lines up with AccuWeather’s forecast, because TWN is very generous for Tomorrow, and EC is generous for Tomorrow and Thursday, while not giving much for Friday. More in part 4!
PART 4 – What is the precipitation forecast?
It’s table time again! This forecast will probably not be the most accurate thing in the world, because my forecasts are going all over the place. I’ll probably send a more accurate forecast in a post tomorrow, with more certain expected conditions for Wednesday night, all of Thursday, and Friday night.
| EC | AW | TWN | Forecast | |
| Tuesday day | Nothing | Nothing | Nothing | Nothing |
| Tuesday night | A shower or thunderstorm overnight | Nothing | A shower overnight, <1 mm | A shower, possibly with some thunder, overnight, <1 mm |
| Wednesday day | A couple of showers or thunderstorms | A shower or thunderstorm in the morning, 1-3 mm | A shower or thunderstorm or two, 2-4 mm | A shower or thunderstorm or two, 2-4 mm |
| Wednesday night | Light rain | Nothing | A couple of showers or strong thunderstorms in the evening, and a shower or thunderstorm overnight, ~1 mm | Some rain and thunderstorms |
| Thursday day | Periods of rain | Nothing | Nothing | Possible rain |
| Thursday night | Periods of rain | A couple of showers in the evening, 3-5 mm | Nothing | Possible rain |
| Friday day | A shower or two | A couple of showers in the afternoon, 2-4 mm | A couple of showers in the afternoon, <1 mm | A couple of showers in the afternoon, 1-4 mm |
| Friday night | A couple of showers | Periods of rain in the evening, 2-4 mm | A couple of showers in the evening, <1 mm | Some showers |
| Saturday day | Nothing | Nothing | Nothing | Nothing |
Final forecast
Today: High of 30, maybe 31. No precipitation in the day, but we might get something overnight tonight. Low near 17.
Tomorrow: The high will probably land in the mid 20s, but it might end up being in the low 20s. The low will be 16 or 17. There will also be some showers and thundershowers at times in the day and night.
Thursday: High near 20, and low 13. Possible showers, but not thunderstorms throughout the day and night.
Friday: Another high around 20, and a low near 14. There will be a couple of showers at times, most likely in the afternoon and evening.
Weekend: No precipitation, temperatures warming.
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