Weather Blog: Pattern Change, High Heat vs. Thunderstorms

Posted at 7:35 AM, Jul 06, 2020
and last updated 2020-07-06 08:35:07-04

Good Monday bloggers,

I hope you had a great 4th of July weekend. We are now starting the second week of July and a pattern change arrives at the end of the week.

A strong upper level high will form in the southwest USA. This is also called an anticyclone which is the opposite of a cyclone. A cyclone is a storm system, or upper level low or surface low. During the summer these anticyclones can create heat waves. At this time it looks like this upper level high will stay in the southwest USA/southern Rockies. A series of troughs (cyclones) will track across the northern Rockies to Great Lakes. This creates a zone between high heat and much cooler air. In this zone you will get rounds of thunderstorms. They form in the northern Plains during the afternoon and then track southeast overnight as large complexes of thunderstorms. These large thunderstorm complexes are also known as Mesoscale Convective Complexes (MCS). Sometimes you can get new thunderstorms to form around here during the afternoon as well. Let's go through this forecast.


MONDAY: Today will be like the last several days. Cumulus clouds will build and a few will become cumulonimbus clouds. So, a few locations will experience a brief shower or thunderstorm. It looks like the main concentration of the showers and thunderstorms will be west across central Kansas. Highs will be around 90 with high humidity and a light wind. The cumulus and cumulonimbus clouds will fade away after sunset as we lose the heat of the day.


TUESDAY-WEDNESDAY: These days will see less of a chance for even isolated showers and thunderstorms as highs reach 90-95. The humidity will be high and the wind will be up a bit to 10-15 mph from the south.


WEDNESDAY NIGHT-THURSDAY: The pattern change begins at this time. We will be watching for a bigger area of thunderstorms to form Wednesday evening north of I-80 across Nebraska and the Dakotas. Once they form they will track southeast.


Here is an image of 5 AM Thursday. You can see we are in a complex of thunderstorms. We are confident that we will see the thunderstorm complexes, but confidence is lower on the track of each complex. It looks like we may be in the thunderstorm zone Thursday and Friday.


THURSDAY AFTERNOON: The morning complex will be long gone as we reach highs in the 80s. Look at the high heat in southwest Kansas where highs will reach 105-110. The zone is still in place.


THURSDAY NIGHT-FRIDAY MORNING: Another complex is rolling through. These thunderstorm complexes can bring 1" to 2" of rain and strong winds.


FRIDAY AFTERNOON-SUNDAY: There will not be large thunderstorm complexes every day, and this may be a period where we don't see a big complex. But, we could still see smaller showers and thunderstorms. Also, the high heat remains in place out west. We will see highs in the 80s with highs 100-110 in the western plains.

Could the high heat make it here? Yes, but if it does it won't be as hot as it will be out west due to the higher humidity. Not, sure what is worse, dry heat or humid heat. Also, if it arrives it would be next week and last only 2-3 days.


RAINFALL FORECAST THE NEXT 7 DAYS: It will be mostly dry through Wednesday so this is really a rainfall forecast for days 4-7. Again, we are confident that some locations will see 2"-4" of rain. We are not confident just exactly where the zone will set up. This data is good news for some very dry yards and farms. Yes, I am aware there are locations that have seen some nice rain the last 5 days. But, most need rain.


Have a great week and stay healthy.