660  
FXUS63 KLOT 020530  
AFDLOT  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE, IL  
1230 AM CDT SAT AUG 2 2025  
   
KEY MESSAGES
 
 
- WILDFIRE SMOKE WILL CONTINUE TO CAST A MILKY LOOK TO THE SKY  
FOR THE FORESEEABLE FUTURE.  
 
- PLEASANT WEATHER CHARACTERIZED BY SEASONABLY COOL TEMPERATURES  
AND LOW HUMIDITY LEVELS WILL PREVAIL THROUGH EARLY NEXT WEEK.  
 

 
   
DISCUSSION
 
 
ISSUED AT 140 PM CDT FRI AUG 1 2025  
 
THROUGH SATURDAY:  
 
A SURFACE HIGH PRESSURE SYSTEM CENTERED OVER THE GREAT LAKES  
WILL SERVE AS THE PRIMARY INFLUENCE ON OUR WEATHER TONIGHT AND  
TOMORROW. INCOMING UPPER-LEVEL CLOUD COVER WILL LIMIT OTHERWISE  
IDEAL CONDITIONS FOR RADIATIONAL COOLING TONIGHT (LIGHT WINDS,  
LOW HUMIDITY LEVELS). OVERNIGHT LOWS WILL RANGE FROM THE LOWER  
50S IN OUTLYING AREAS TO THE LOWER 60S LAKESIDE. TOMORROW LOOKS  
SIMILAR TO TODAY WITH AN EAST-NORTHEASTERLY BREEZE AND HIGHS IN  
THE MID TO LOCALLY UPPER 70S. UPPER-LEVEL SMOKE WILL CONTINUE TO  
PROVIDE A MURKY LOOK TO THE SKY FOR THE FORESEEABLE FUTURE.  
 
BORCHARDT  
 
SATURDAY NIGHT THROUGH FRIDAY:  
 
HIGH PRESSURE CENTERED ACROSS WISCONSIN AND LOWER MICHIGAN ON  
SUNDAY WILL DRIFT EASTWARD TO THE CANADIAN MARITIME PROVINCES  
THROUGH THE MIDDLE OF NEXT WEEK. THE BROADER MID-LEVEL FLOW  
ACROSS THE CONUS WILL REMAIN MORE-OR-LESS BLOCKED WITH A 600DAM  
500 HPA RIDGE OVER THE SOUTHWEST STATES AND A WEAKER RIDGE  
CROSSING SOUTHERN CANADA. BETWEEN THESE RIDGES AND THE SURFACE  
HIGH TO THE EAST, A MID-LEVEL TROUGH OVER THE CENTRAL CALIFORNIA  
COAST WILL ROUND THE SOUTHWEST RIDGE INTO THE CENTRAL CONUS ON  
MONDAY BEFORE BECOMING INCREASINGLY SHEARED ACROSS OUR AREA  
TUESDAY INTO WEDNESDAY. ATLANTIC-BASED MOISTURE WILL BE DRAWN  
NNW TOWARD THE LOWER OHIO AND MID-MISSISSIPPI RIVER VALLEYS BY  
MONDAY AND ESPECIALLY TUESDAY. THIS WOULD ULTIMATELY SUPPORT  
ISOLATED TO WIDELY SCATTERED DIURNALLY-DRIVEN THUNDERSTORMS AS  
CLOSE AS CENTRAL ILLINOIS MONDAY AFTERNOON AND OVER THE ENTIRE  
FORECAST AREA ON TUESDAY AND POSSIBLY INTO WEDNESDAY. A MAJORITY  
OF THE FORECAST AREA SHOULD REMAIN DRY DURING THIS PERIOD,  
THOUGH WILL CONTINUE TO ADVERTISE HIGHER CHANCES ON TUESDAY. A  
BROAD TROUGH CROSSING THE FAR NORTHERN GREAT LAKES LATE IN THE  
WEEK WILL ERODE A LOW-AMPLITUDE RIDGE NOSING NORTHEASTWARD INTO  
THE SOUTHERN GREAT LAKES, SUPPORTING THE POTENTIAL FOR AN MCS  
EPISODE SOMEWHERE ACROSS THE WESTERN GREAT LAKES DURING THIS  
TIME.  
 
KLUBER  
 

 
   
AVIATION /06Z TAFS THROUGH 12Z SUNDAY/
 
 
ISSUED AT 1230 AM CDT SAT AUG 2 2025  
 
HIGH PRESSURE WILL KEEP VFR CONDITIONS AROUND THE TERMINALS  
THROUGH THE CURRENT PERIOD. WINDS WILL REMAIN ONSHORE AT OR  
BELOW 10 KNOTS THIS AFTERNOON. WILDFIRE SMOKE REMAINS IN THE  
REGION FOR HAZIER SKIES AND MAY RESULT IN OCCASIONAL VISIBILITY  
REDUCTIONS TO MVFR LEVELS.  
 
DK  
 

 
   
LOT WATCHES/WARNINGS/ADVISORIES
 
 
IL...AIR QUALITY ALERT UNTIL MIDNIGHT CDT TONIGHT FOR ILZ005-ILZ006-  
ILZ012-ILZ013-ILZ020-ILZ021-ILZ103-ILZ104-ILZ105-ILZ106-  
ILZ107-ILZ108.  
 
IN...AIR QUALITY ALERT UNTIL MIDNIGHT CDT TONIGHT FOR INZ001-INZ002-  
INZ010-INZ011.  
 
LM...NONE.  
 

 
 

 
 
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