Weekend Weather Forecast: What's in the North Shore Clouds?

Weekend Weather Planner for the North Shore

Looks like the majority of the weekend will be rain free with the best chance of rain staying just to our north. The big story this weekend will be the developing heat wave as an expanding heat dome shifts northeast into our region. Have plenty of water handy and stay cool and beware of the dangers of heat exhaustion and heat stroke.

Saturday: Partly sunny to mostly cloudy and very warm. Partly to mostly cloudy skies at night.

• Low temp: 68 degrees Fahrenheit.
• High temp: 87 degrees Fahrenheit. 
• Wind: South to southeast at 10-18 mph.

Sunday: Partly sunny and hot. Partly to mostly cloudy skies at night.

• Low temp: 69 degrees Fahrenheit. 
• High temp: 91 degrees Fahrenheit.
• Wind: South to southwest at 10-15 with gusts to 25 mph.

Monday: Mostly cloudy with a 30 percent chance of isolated showers and t-storms from 5 a.m. to 10 a.m. and again from 6 p.m. to 2 a.m. Tuesday.

• Rain Amounts: 0.10 to 0.40 inches
• Low temp: 74 degrees Fahrenheit.
• High temp: 92 degrees Fahrenheit. 
• Wind: West to southwest at 5-10 mph

Your Week Ahead: July 15 to July 22 (Northeast Cook County)

A frontal boundary in the area may cause a few isolated showers and t-storms during the first half of the week with hot temperatures likely throughout the entire period.

Temperature Trends: Temperatures will average several degrees above normal with a heat wave likely.

Precipitation Trends: Rain will average below normal.

Skies will be partly cloudy Friday with the best chance of thunderstorms staying to our north and northwest over Minnesota and Wisconsin. A developing heat dome to our south will slowly push north with the best chance of storms through Sunday expected to stay mainly to our north.

A frontal boundary will be located just to our north and with any upper-air disturbances moving southeast in the flow, there may be an isolated shower or t-storm sometime on Monday. A similar pattern will be in place through late Tuesday or early Wednesday with just a few showers and t-storms possible.

It looks like the heat will be the biggest story during the entire period with highs in the 90s beginning on Sunday with a possible string of 90s for a five to ten day period. Peak heat index values during this time could approach 95 to 100. In fact over many parts of the Midwest, this could turn out to be a dangerous heat wave as it looks like it will persist for some time.

The chance of rain during the middle and end of next week appears to be low as the heat dome continues to expand north. This will help to cap the atmosphere which prevents the development of storms due to warm air aloft.

It is possible that the heat wave may begin to break around July 24 and July 25 as a front pushes into the area. This will also help to increase the probability of rain and storms and help winds to shift more northerly allowing for cooler air to filter in off the Great Lakes.

Your Weekly Weather Facts:

The thunderstorm complex that moved through our area on Monday was a classic derecho event. The definition of a derecho is "a widespread, long-lived windstorm that is associated with a band of rapidly moving showers and t-storms," according to the National Weather Service.

This particular event began in Iowa and moved all the way to West Virginia before weakening. Storms were moving at 70 mph and produced widespread damaging winds of 60 to 85 mph across all of northeast Illinois. On average, a derecho occurs over northern Illinois one to two times every spring/summer season.

Due to the developing heat wave, everyone should take time to review heat disorder systems:

http://www.weather.gov/om/brochures/heat_wave.shtml
Source: National Weather Service-Chicago Office