Chinook

We had a 90-degree streak of 5 days, with 95.9 deg on Wednesday, KFNL airport was 100, as 37.8 C is 100 F. KFNL 192356Z AUTO 29007KT 10SM CLR 32/09 A3006 RMK AO2 LTG DSNT NE SLP110 T03170089 10378 20311 55001

Southeast Nebraska may have had a realistic 7500- 8000 J/kg of CAPE when Beatrice NE had 92/79 today, 97/79 measured in nearby Kansas.

At this point, you start wondering if it is maybe really dry ground right in the STL metro area, or measurement bias. My bet is on really dry ground. Back more than a week ago, the dew point was about 60-65 when they hit 102 or 103, so there was less water vapor. Actually, I'm not really sure why water vapor (like higher PWs or higher dew points) would cut back on the high temperature of the day. Does the vapor have a higher heat capacity than O2 and N2?

Not many people are talking about this, but the header on TropicalTidbits said that the GFS was updated in some fashion on July 19th. Browsing through the GFS surface temp anomalies, I am guessing now the GFS is seeing the urban heat islands (around the world? around the USA?) Check out the temp anomalies of some 4-5 deg C in Atlanta above the background temp anomaly. 4-5 deg C is a lot, perhaps too much. I wonder if the new GFS is too warm with surface temperatures. That would be new.

funnel cloud spotted on the supercell SE of Iowa City

I guess the USA is not the only country feeling the abnormal heat -- Hottest day in Shanghai’s history Shanghai, China—with 24 million residents, the world’s eighth-largest city—had its hottest day ever recorded on Friday. Temperatures reached a preliminary high of 40.9°C (105.6°F) at the Xujiahui station in Shanghai, where temperatures have been monitored since 1872. The previous record high was 40.8°C, recorded in 2013, with the runner-up of 40.6°C also occurring that year. https://www.wunderground.com/cat6/heat-sweat-and-ozone-plague-us-all-time-high-shanghai?__prclt=YBaC6N39

Yesterday (July 20) heat indices went from 110-115 in Missouri and Iowa, at maximum. At least one town in Missouri had 95/80. Today (July 21) it is already getting up to a heat index of 109 in the same places in Missouri where you see the 114 on this map. Yuck!

Severe storms should be relatively active tomorrow in IA/WI/MN. Eastern Iowa could have 5000-6000 J/kg of CAPE, with some potential for over 200 m2/s2 of SRH and shear in the range of 30kt - 40kt. CAMS suggest several areas of storms.

I have always thought that well-formed bow echoes look kind of like a arch-shaped spaceship.

This is a well-formed bow echo with some 70-80 kt winds detected in the clouds

The Rockies have swept the Padres and scores 36 runs in the last 3 games. The ball really flies when there is low density, like when it is hot in Denver! Also, the Rockies are hitting very well, and they have a lot of motivation to beat the Diamondbacks in the Wild Card race.

0-6 km shear should be reasonably impressive for July. If storms form in Ohio or Indiana, they could get severe quickly. the 12z NAM has 41 kt of shear at Cleveland, 35 kt in northern Indiana tomorrow. For 0-3km SRH, there are some big differences between the 12z NAM and 18z NAM for Ohio. So maybe worth watching.

9,414,140 people in Excessive Heat Warnings in the central U.S. Magenta area in MO/IA/KS/IL/NE

We should have some temps up around 96 for some of us tomorrow, with 101 in southwest Nebraska. This GFS 21-hr forecast should be 5-9 degrees too warm for the Front Range corridor here, and perhaps some 5 degrees too warm in other locations. I don't know why this is happening. The GFS temp profiles are super-adiabatic for too much of the lower atmosphere near Denver. The weird part is that the GFS has been too moist and too cool with some of the Midwest in various times this summer-- seemingly the opposite boundary-layer problem. The GFS should be a perfectly fine short-range model when cool thunderstorms are not dominating the temperature. NCEP keeps making the GFS better, right? Of course. In fact, the government says there will be a new NCEP global model created in 2018, that will be better than the GFS. My $5 bet is that the new model will be delayed by a year. In fact, I bet another $5 that when the new global model is operational, the U.S. will still be trying to catch up with the ECMWF modeling systems for a long time.

The summer rainfall, including our North American Monsoon contribution, has been mainly a failure for many of the years I lived here. I moved here in 2006 at the height of the D3 drought. I used the U.S. Drought Monitor archives to find drought designations in past years. Many summers have been warmer than normal.