400  
FXUS63 KDVN 182017  
AFDDVN  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE QUAD CITIES IA IL  
317 PM CDT FRI JUL 18 2025  
   
KEY MESSAGES
 
 
- ACTIVE PATTERN RETURNS TO THE AREA TONIGHT AS WARMER AND MORE  
MOIST AIR MOVES INTO THE AREA.  
 
- RING OF FIRE MOVES OVER THE AREA BRINGING DAILY CHANCES FOR  
THUNDERSTORMS. SOME OF WHICH COULD BE STRONG TO SEVERE WITH  
HEAVY RAIN AND FLASH FLOODING.  
 
- THE HEAT RETURNS IN EARNEST BY THE MIDDLE OF NEXT WEEK.  
 

 
   
SHORT TERM /THROUGH SATURDAY/
 
 
ISSUED AT 146 PM CDT FRI JUL 18 2025  
 
IMPACTFUL WEATHER BEGINS TONIGHT ACROSS THE AREA AS RETURNING  
LOW LEVEL MOISTURE ADVECTS INTO THE AREA AHEAD OF A WEAK WAVE  
MOVING THROUGH THE FLOW. WHERE THE EDGE OF THIS DEWPOINT AXIS  
SETS UP WILL SEE THE POTENTIAL FOR REPEATED ROUNDS OF  
THUNDERSTORMS OVERNIGHT. CAMS ARE IN GOOD AGREEMENT ON A MCS  
TRACKING SE INTO THE AREA NEAR DAYBREAK. CONSENSUS HAS THIS  
PRECIP WEST OF A LINE FROM CAMBRIDGE IL TO DBQ, IA. SOME SHIFT  
EAST OR WEST IS POSSIBLE. CAMS ALSO HAVE A WING OF WAA  
CONVECTION SETTING UP A POTENTIAL FLASH FLOOD SCENARIO FOR  
SATURDAY MORNING, ESPECIALLY IN URBAN AREAS. AS SUCH, A FLOOD  
WATCH FOR FLASH FLOODING HAS BEEN ISSUED FROM TONIGHT INTO  
SUNDAY MORNING WHEN ANOTHER ROUND OF STORMS ARE POSSIBLE. PWATS  
THROUGH THE PERIOD EXCEED 2 INCHES AS WELL.  
 
ALSO, THIS MCS LOOKS TO HAVE WINDS MIXING TO THE GROUND BASED ON  
THE CAMS. THE ENVIRONMENT IS SUPPORTIVE OF STRONG TO SEVERE  
STORMS DURING THE MORNING. THIS IS NOT THE TYPICAL TIME FOR  
SEVERE WEATHER ACROSS THE AREA, BUT IT LOOKS LIKE ON TOP OF THE  
FLASH FLOODING RISK, WE COULD HAVE A SEVERE WIND RISK AS WELL.  
SPC HAS THE AREA IN A SLIGHT RISK TOMORROW, WHILE MOST OF THAT  
IS IN THE EVENING, THERE IS STILL A THREAT IN THE AM. AFTER  
THIS, A RELATIVELY QUIET REST OF THE PERIOD AS THE SFC  
BOUNDARY, LIKELY REINFORCED BY ANY OUTFLOW FROM THE EARLIER  
STORMS. STORMS WILL TRY TO FORM LATER IN THE PERIOD, ESPECIALLY  
NW OF THE CWA ON THIS BOUNDARY AND MARCH EAST ALONG THE BOUNDARY  
INTO SUNDAY MORNING.  
 

 
   
LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/
 
 
ISSUED AT 146 PM CDT FRI JUL 18 2025  
 
IMPACTFUL WEATHER IS EXPECTED THROUGH THE ENTIRE LONG TERM  
PERIOD AS THE RING OF FIRE MCS TRACK CONTINUES ACROSS OUR AREA.  
WE WILL BE DEALING WITH SEVERE WEATHER, FLASH FLOODING, LIKELY  
RIVER FLOODING AND DANGEROUS HEAT THROUGH THIS PERIOD. SATURDAY  
EVENING LOOKS BE RATHER POTENT WITH LARGE INSTABILITY, DEEP  
LAYER SHEAR, PWATS OVER 2 INCHES, A STRONG WAVE FOR THE SUMMER  
AND A STALLED OUT BOUNDARY. THIS WAVE, OR RATHER A SERIES OF  
SUCCESSIVE WAVES WILL MOVE THROUGH THE AREA DURING THE DAY ON  
SUNDAY INTO MONDAY MORNING. THE GFS HAS THE SFC BOUNDARY  
RETREATING NORTH BRINGING THE MAIN RING OF FIRE NORTH. THE ECM  
KEEPS THE BOUNDARY NEAR US. I THINK THE ECM HAS THE RIGHT IDEA  
AS THE WAVES WILL STRUGGLE TO MIX THE BOUNDARY NORTH WITH  
CONVECTIVE DEBRIS, THIS MEANS MORE SHOWERS AND STORMS SUNDAY  
NIGHT INTO MONDAY. TOWARDS THE MIDDLE OF THE WEEK THE HEAT  
SHOULD BUILD INTO THE AREA.  
 
FOCUSING ON SATURDAY EVENING INTO SUNDAY MORNING. THIS SETUP HAS  
ME THE MOST CONCERNED FOR THE AREA AND REALLY THE IMPETUS FOR  
THE FLOOD WATCH. AS THE BETTER WAVE MOVES INTO THE AREA, THE  
STALLED OUT BOUNDARY WILL RETREAT SOME TO THE NORTH. DEEP LAYER  
SHEAR SUGGESTS SPLITTING SUPERCELLS WILL DEVELOP ALONG THE  
BOUNDARY. 12Z HRRR HAD THOSE SUPERCELLS NEAR US, THE 18Z HAS  
THEM FURTHER WEST. REGARDLESS, THESE SUPERCELLS, WHEREVER THEY  
FORM, WILL HAVE THE POTENTIAL FOR ALL MODES OF SEVERE WEATHER.  
THEY WILL LIKELY BECOME OUTFLOW DRIVEN AS A SERIES OF MCSS RUN  
DOWN THE BOUNDARY AND INTO OUR AREA OVERNIGHT. DEEP LAYER SHEAR  
WILL SUPPORT BALANCED COLD POOL/SHEAR PROCESSES AND SEVERE WIND  
PRODUCING STORMS. ALSO, STORMS NEAR THE BOUNDARY MAY POSE A  
TORNADO THREAT AS THEY MOVE ACROSS THE AREA INTO THE OVERNIGHT.  
COINCIDENT WITH THE SEVERE RISK, HEAVY RAIN AND FLOODING ARE  
LIKELY TO BEGIN QUICKLY AS WARM RAIN PROCESSES AND HIGH PWATS  
RAPIDLY STACK UP THE RAIN. THE FLOOD WATCH MAY NEED TO BE  
ADJUSTED, BUT WANTED TO GET IT OUT TO COVER TONIGHT'S LOWER END  
RISK AND TOMORROWS ENHANCED RISK. AREAS THAT SAW FLASH FLOODING  
LAST WEEK ARE ESPECIALLY SUSCEPTIBLE AND THOSE LIVING ALONG  
CREEKS AND RIVERS THAT FLOODED SHOULD REMAIN ABREAST OF THE  
WEATHER AND HAVE MULTIPLE WAYS TO RECEIVE WEATHER WARNINGS  
OVERNIGHT.  
 
THE PATTERN LOOKS TO BE VERY FAVORABLE LATE IN THE WEEKEND  
THROUGH EARLY NEXT WEEK FOR SEVERAL STORM COMPLEXES TO  
TRAVERSE IN/NEAR THE AREA, AS WE'LL RESIDE JUST NORTH OF  
THE UPPER RIDGE/HEAT DOME WITHIN THE 'RING OF FIRE' AND  
BARRAGE OF RIDGE RIDERS ON THE SOUTHERN PERIPHERY OF THE  
STRONGER MID LEVEL FLOW TRAVERSING THE INTERNATIONAL BORDER.  
THIS WILL BRING ABOUT PERHAPS GREATER CONCERNS FOR A MORE  
WIDESPREAD SEVERE WEATHER THREAT DUE TO THE LIKELIHOOD OF  
MCS'S, ALONG WITH TORRENTIAL RAIN AND FLOODING PARTICULARLY  
AS SOILS ARE LIKELY TO BE QUITE SATURATED AND RIVERS RUNNING  
HIGH IN THOSE AREAS THAT RECEIVE NOTEWORTHY RAINFALL IN THE  
DAYS PRIOR.  
 
BY WEDNESDAY, THERE IS FAIRLY GOOD AGREEMENT THAT THE UPPER  
RIDGE WILL BUILD INTO THE REGION SHUNTING THE MAIN STORM  
TRACK TO OUR NORTH. THIS WILL BRING ABOUT THE THREAT FOR  
DANGEROUS HEAT WEDNESDAY WITH HIGHS WELL INTO THE 90S AND  
DEW POINTS IN THE MID/UPPER 70S (POSSIBLY 80+F IN SOME AREAS  
DUE TO EVAPOTRANSPIRATION FROM MATURING CORN CROPS) OWING TO  
HEAT INDEX READINGS OF 100-110+. THIS DANGEROUS HEAT COULD  
EXTEND INTO THURSDAY, PARTICULARLY ACROSS OUR SOUTH/EAST AHEAD  
OF A COLD FRONT. THIS FRONT WILL ALSO BRING A RETURN OF STORM  
CHANCES OVER THE LATTER PORTION OF NEXT WEEK AND POSSIBLY THROUGH  
NEXT WEEKEND.  
 

 
   
AVIATION /18Z TAFS THROUGH 18Z SATURDAY/
 
 
ISSUED AT 145 PM CDT FRI JUL 18 2025  
 
MVFR CIGS WILL BECOME VFR CIGS AS CLOUDS SCATTER OUT THIS  
AFTERNOON. WINDS WILL REMAIN LIGHT THROUGH THE PERIOD.  
THUNDERSTORMS NEAR DAYBREAK ARE POSSIBLE INTO THE MORNING. THESE  
STORMS WILL LEAD TO MVFR VSBYS AND POSSIBLY IFR VSBYS IN THE  
HEAVIEST STORMS.  
 

 
   
HYDROLOGY
 
 
ISSUED AT 1157 AM CDT FRI JUL 18 2025  
 
THE ATMOSPHERIC SET UP OVER THE WEEKEND AND THROUGH TUESDAY  
POINTS TO A HEAT DOME OVER THE PLAINS WITH IOWA/ILLINOIS IN OR  
NEAR THE ACTIVE ORGANIZED THUNDERSTORM TRACK. SUCH A SCENARIO  
POINTS TO THE POTENTIAL FOR ROUNDS OF HEAVY RAINFALL.  
 
OVER THE PREVIOUS SEVEN DAYS EASTERN IOWA AND NORTHERN ILLINOIS  
HAS RECEIVED ANYWHERE FROM 175 TO OVER 500% OF THE NORMAL  
RAINFALL WITH A VAST MAJORITY OF THAT OCCURRING IN THE 48-HOUR  
TIME PERIOD OF JULY 10-11TH. THIS RAINFALL HAS RESULTED IN A  
20-40% IMPROVEMENT IN SOIL MOISTURE AND HAS ESSENTIALLY  
ELIMINATED THE ABNORMALLY DRY TO MODERATE DROUGHT CONDITIONS  
ACROSS EASTERN IOWA. HOWEVER, SOIL ANOMALIES ARE STILL -20 TO  
-40% DRY WITH THE WORST CONDITIONS EAST OF THE MISSISSIPPI WHERE  
ABNORMALLY DRY TO MODERATE DROUGHT PERSISTS.  
 
WHILE RIVER LEVELS ARE FALLING FROM THE HEAVY RAINFALL OF JULY  
10-11TH, AREA TRIBUTARIES ACROSS EASTERN IOWA ARE RUNNING ABOVE  
TO MUCH ABOVE NORMAL FOR MID- SUMMER. TRIBUTARIES IN ILLINOIS  
ARE NEAR NORMAL WITH THE MISSISSIPPI RUNNING NORMAL TO ABOVE  
NORMAL.  
 
WEATHER MODELS THIS WEEKEND THROUGH TUESDAY HAVE ATMOSPHERIC  
MOISTURE LEVELS INCREASING TO AT LEAST 2 INCHES WHICH IS GREATER  
THAN THE 90TH PERCENTILE FOR JULY. ADDITIONALLY, WEATHER MODELS  
INDICATE A TROPICAL MOISTURE CONNECTION DEVELOPING BY EARLY  
NEXT WEEK WITH THE GULF. WITH FREEZING LEVELS IN THE ATMOSPHERE  
PROJECTED TO BE VERY HIGH, WARM RAIN PROCESSES HAVE A HIGH  
PROBABILITY OF DOMINATING WHICH WILL LEAD TO VERY EFFICIENT  
RAINFALL PRODUCTION ALONG WITH A HIGH PROBABILITY OF RAINFALL  
RATES OF 1 TO 2+ INCHES PER HOUR.  
 
BASED ON AVAILABLE INFORMATION, IT APPEARS THERE WILL BE A  
DAILY NOCTURNAL STORM COMPLEX THAT ARRIVES IN EASTERN IOWA IN  
THE PRE-DAWN HOURS AND DISSIPATES OVER ILLINOIS AROUND MID-DAY.  
BOUNDARIES LEFT OVER FROM THE NOCTURNAL COMPLEX WILL DICTATE  
WHERE NEW STORMS DEVELOP DURING THE AFTERNOON/EVENING. THIS  
SCENARIO LOOKS TO PLAY OUT THREE TO FOUR TIMES THROUGH TUESDAY.  
 
WHAT IS NOT FULLY KNOWN YET IS WHETHER OR NOT STORMS WILL REPEAT  
OVER THE SAME AREAS. IF THIS OCCURS (THE PROBABILITY IS AROUND  
50%), THEN EXCESSIVE RAINFALL RATES OF 2+ INCHES PER HOUR WOULD  
LEAD TO RAPID RUNOFF OF WATER INTO LOW LYING AREAS AND RESULTANT  
FLASH FLOODING. REPEATED ROUNDS OF HEAVY RAINFALL WOULD THEN  
RESULT IN RISING RIVER LEVELS AND THE POTENTIAL FOR RIVER  
FLOODING.  
 
THE WEATHER PREDICTION CENTER HAS A DAILY SLIGHT RISK OF  
EXCESSIVE RAINFALL THROUGH TUESDAY. THE TIME PERIOD OF SATURDAY  
NIGHT INTO SUNDAY IS THE MOST CONCERNING. THE PROBABILITIES FOR  
EXCESSIVE RAINFALL ARE AT THE UPPER END OF THE SLIGHT RISK.  
 
THE FOLLOWING TRIBUTARY RIVERS WILL NEED TO BE ESPECIALLY  
WATCHED THROUGH THE END OF JULY SINCE THEY ALREADY HAVE ABOVE  
NORMAL STREAMFLOW; CEDAR, IOWA, SKUNK AND WAPSIPINICON. GENERAL  
RISES ON THE MISSISSIPPI ARE ALSO EXPECTED.  
 

 
   
DVN WATCHES/WARNINGS/ADVISORIES
 
 
IA...FLOOD WATCH FROM 1 AM CDT SATURDAY THROUGH SUNDAY AFTERNOON  
FOR IAZ051>053-063>068-076>078-087>089-098-099.  
IL...FLOOD WATCH FROM 1 AM CDT SATURDAY THROUGH SUNDAY AFTERNOON  
FOR ILZ015-016-024>026-034-035.  
MO...NONE.  
 

 
 

 
 
SHORT TERM...GIBBS  
LONG TERM...GIBBS/MCCLURE  
AVIATION...GIBBS  
HYDROLOGY...08  
 
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