Dog Days Of August Are Here
Don't Forget About Man's Best Friend
The dog days of August are here and because of climate change there are more today than there were about 50 years ago.
The origin of the term dog days according to the National Weather Service can be traced back thousands of years to the era of the Roman Empire:
"It refers to the dates from July 03 through August 11, which is 20 days prior and 20 days after the star Sirius rises and falls in conjunction with the sun. Sirius was knows as the “Dog Star”, because it is the brightest star in the constellation Canis Major (Large Dog)."
Climate Central considers it a dog day when asphalt surfaces reach 125° which is hot enough to burn human skin and dangerous for dogs' unprotected paws. Over the last 50 years Chicago has seen an increase of 9 dog days according to this definition. Chicago was one of 246 cities included in a study of the change in 77° days or warmer at a given location. 94% of the cities analyzed have seen an increase in "dog days" since 1970.
Heat stroke is not just something we humans have to worry about. Dogs risk having heat stroke if there is too much physical exertion or exercise in hot environments. The danger to dogs from heat is increasing as summers continue to get hotter and last longer due to climate change.
According to Climate Central, heat illness and exertion are also a serious threat to our canine pals:
Physical activity during high temperatures increases the risk of heat stress or heat stroke in dogs. A study of veterinary records of dogs in the U.K. found that exercise triggered nearly three-quarters (74.2%) of all heat-related illnesses, compared to 5% that were due to being confined in a vehicle. Older and flat-faced dogs (brachycephalic breeds, e.g. bulldogs, shihtzus, and pugs) were at greater risk of developing heat-related illness just by sitting outside in hot weather. Other risk factors for heat stroke in dogs include:
If you want to test to see if asphalt is too hot for your dog's unprotected paws just place the back of your hand on the pavement. If you pull your hand away in under 8 seconds because it is too hot, you need to find either a grassy or shaded surface to walk your dog.
Don't forget to give you dog plenty of fresh, clean water. Avoid exercise during the hottest part of the day and never leave dogs in a car without air conditioning.
This summer has more dog days left and we will see quite a few over the next several days.
The GFS model has our highs today in the upper 80s to near 90°. The high humidity will make it feel at least like the lower 90s this afternoon.
The next several days will feature very high levels of humidity. The worst combination of heat and humidity should arrive on Tuesday. The heat index or apparent temperature values could reach or exceed 100°.
Dew points will hover between the upper 60s to near 70° today and tomorrow (and beyond). Gusty southwest winds kick in on Sunday and will continue to transport very moist air from the Gulf of Mexico to the Midwest.
While most of the weekend will be dry it looks like the greatest threat of some scattered thunderstorms today will be during the latter part of the afternoon. Sunday's highest threat of rain comes in the evening and overnight.
These tropical level dew points should stick around through Thursday before dropping dramatically just in time for the weekend.
Relative humidity is one way to express the amount of water vapor in the air but dew points are the preferred measurement of moisture in the air for meteorologists like me. The dew points through Thursday will be in the "uncomfortable" to "sweltering" category.
The National Blend Of Models drops us back to about average on Monday mainly because of more cloud cover and a better chance of rain. That is the exception to an otherwise hot forecast through Thursday.
We are getting used to the hazy sunshine by now this summer. The HRRR Model vertically integrated smoke forecast suggests wildfire smoke from western fires and Canada will be with us again today.
Here are some articles related to wildfire smoke that you may be interested in:
The long range temperature probability forecasts start off warm and then transition us back to about average. The 6-10 day forecast has outlooked Chicago for above average temperatures from August 12th through August 16th. The longer range 8-14 day forecast favors us for about average temperatures overall from August 14th through August 20th. Average highs are in the lower to middle 80s for the start to August.
More Active Pattern Means Some Hope For Rain
Friday was the 8th straight day at O'Hare without any measurable rain. Our northern suburbs desperately need rainfall to put a dent in the ongoing drought. Storms may be scattered over the weekend and into early next week with a more unsettled pattern but they will bring relief for at least portions of the area.
Here is a recap from my post on Friday with the updated drought statistics:
Mostly good news from the latest US Drought Monitor analysis. The good news is that portions of Illinois in a moderate and severe drought have dropped slightly. 6% of the state is now in a moderate drought (level 1 out of 4 levels) down from 7.17% last week. 2.1% of the state is now in a severe drought (level 2 out of 4 levels) down from 2.31% last week. Northern Illinois is the only part of the state reporting drought conditions. The bad news is the portion of the state considered "abnormally dry" has increased to 10.99% from 9.74% last week.
The latest GFS model shows periods of rainfall are possible through most of next week. It isn't the widespread more drenching rain we need but anything at this point will help.
Some of the storms today into tonight might be strong to severe. Sunday night is another time period to watch for possible severe weather.
The Storm Prediction Center has areas north and west of Chicago in a marginal risk for severe storms today into tonight. The biggest threat would be damaging winds and large hail but even an isolated tornado is possible.
The GFS model total rainfall forecast through Tuesday morning reflects the character of the unsettled pattern we are in. It will lead to some locally heavy rainfall in some spots with a lot less rain in others. The range of rainfall in the forecast is from as little as under a half inch to as much as nearly and inch and a half.
The Midwest region's drought news this week was discouraging overall. The good news is the area in a moderate drought fell from 27.33% to 26.26%. The area in a severe drought increased to 17.59% from last week's 16.74%. The area in an extreme drought nearly doubled to 6.72%, up from 3.73% last week.
The drought numbers for the west continue to stagger me. The area in the highest levels of drought (extreme and exceptional) diminished slightly but the area in the lower levels of drought (moderate and severe) increased at least slightly. Nearly two-thirds of the region is in an extreme drought and about a quarter of it is in an exceptional drought.
Bad news in the longer range precipitation probability forecasts. They keep us relatively dry well into August. The latest 6-10 day forecast has the Chicago area favored for about below average precipitation from August 12th through August 16th. The longer range 8-14 day forecast also favors us for below average precipitation from August 14th through August 20th.
Here is my 7 day forecast:
Today: Partly to mostly sunny, pm sct. showers/t-storms (some strong) High: 87
Sunday: Partly to mostly sunny, sct. showers/t-storms mainly late Low: 70 High: 91
Monday: Mostly cloudy, sct. showers/t-storms likely Low: 72 High: 85
Tuesday: Partly to mostly sunny, sct. shower/t-storm possible Low: 73 High: 91
Wednesday: Partly to mostly sunny, sct. shower/t-storm possible Low: 73 High: 88
Thursday: Partly to mostly sunny, sct. shower/t-storm possible Low: 72 High: 89
Friday: Partly to mostly sunny, cooler & less humid Low: 66 High: 84