WINDY, COOLER—almost autumn-like cool air is to sweep into Chicago on “NNE” winds which arrive after a long, wave-generating trek southward the length of Lake Michigan Tuesday night and Wednesday.
The time such winds spend over Lake Michigan equips them uniquely to develop waves and rip currents—and these features are behind the BEACH HAZARDS STATEMENT which is in effect on our Chicago area beaches into Wednesday night. White-capped waves will populate the lake surface later tonight and Wednesday and swimmers will find water treacherous for swimming Wednesday.
WATCH AS WAVES BUILD in this series of WAVE HEIGHT FORECAST PANELS from 6 pm CDT Tuesday through 9 pm Wednesday:
The cool temps riding into the area will be a bit jarring after Tuesday’s mid 80s—BUT THEY WILL NOT LAST LONG.
We have only 2 days left in August and the 3 month meteorological summer season, which spans June, July and August. Seven of the past 8 months have posted TEMP SURPLUSES IN CHICAGO—and though the temp surpluses in each of the Summer 2023 months have been MODEST—the summer season had managed a 3-month average temp which is among the 20% warmest of any of the past 153 summer seasons here.
September—Chicago’s 3rd-fastest cooling month, may get underway at midnight Thursday night, but its cool temps won’i’t be evident evident in its opening few weeks is current forecast trends hold. That’s a period predicted to see ABOVE NORMAL TEMPS.
In fact, while last week—with its blistering mid-week heat, including last Thursday’s 100° record typing high—finished nearly 7° above normal—this week is to finish a statistical “wash” temperature-wise—then see temperatures TAKE OFF with next week likely to average 10°warmer than this week and finish 12° ABOVE NORMAL. That’s a big change!
NWS Weather Prediction Center (WPC) estimate of TOTAL RAINFALL over the coming 3 days (through 8am EDT Friday 
NWS blended computer forecast model RAINFALL FORECAST through 7pm CDT (8pm EDT) Friday 
REGIONAL TOTAL RAINFALL ESTIMATE from a NWS blend of computer forecast models 
ONE OF SEVERAL SETS OF TRACK FORECAST FOR IDALIA–This one a collection of various model forecasts put together for NHC forecasters–one of the data sets analyzed by NHC forecasters in producing their official track forecast 
A set of predicted Hurricane Idalia tracks produced by the European Centre’s widely regarded ENSEMBLE FORECAST
Types of Damage Due to MAJOR Hurricane Winds
From the National Hurricane Center:
CATEGORY 3 MAJOR HURRICANE:
Devastating damage will occur: Well-built framed homes may incur major damage or removal of roof decking and gable ends. Many trees will be snapped or uprooted, blocking numerous roads. Electricity and water will be unavailable for several days to weeks after the storm passes.
CATEGORY 4 MAJOR HURRICANE:
Catastrophic damage will occur: Well-built framed homes can sustain severe damage with loss of most of the roof structure and/or some exterior walls. Most trees will be snapped or uprooted and power poles downed. Fallen trees and power poles will isolate residential areas. Power outages will last weeks to possibly months. Most of the area will be uninhabitable for weeks or months.
CATEGORY 5 MAJOR HURRICANE:
Catastrophic damage will occur: A high percentage of framed homes will be destroyed, with total roof failure and wall collapse. Fallen trees and power poles will isolate residential areas. Power outages will last for weeks to possibly months. Most of the area will be uninhabitable for weeks or months.
