971  
FXUS63 KDVN 230419  
AFDDVN  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE QUAD CITIES IA IL  
1119 PM CDT MON MAY 22 2017  
   
..AVIATION UPDATE
 
 
   
UPDATE
 
 
ISSUED AT 605 PM CDT MON MAY 22 2017  
 
A SIZABLE SHORT TERM UPDATE WAS ISSUED AT 430 PM, IN INCREASE POPS  
NORTH AND SOUTH, BUT GREATLY REDUCE POPS IN THE CENTRAL AREAS.  
THIS TREND SHOULD CONTINUE INTO TONIGHT, WITH MAINLY DRY  
CONDITIONS ALONG CENTRAL AREAS AND ANY CONVECTION LIKELY REMAINING  
NORTH AND SOUTH OF THE CWA AFTER 7 PM.  
 

 
   
SYNOPSIS
 
 
ISSUED AT 250 PM CDT MON MAY 22 2017  
 
LOTS OF CLOUDS AND COOL CONDITIONS AT 2 PM CDT ACROSS THE FORECAST  
AREA WITH TEMPERATURES MOSTLY IN THE MID TO UPPER 60S WITH SOME  
LOW 70S WHICH IS 5 TO 10 DEGREES BELOW NORMAL FOR LATE MAY. SOME  
LIGHT SHOWERS CAUSED BY A BROAD AREA OF UPPER LOW PRESSURE SYSTEM  
WHICH WILL STAY IN PLACE OVER THE REGION FOR AT LEAST THE NEXT 24  
HOURS FOR MORE COOL AND WET CONDITIONS. SKIES WILL BEGIN TO CLEAR  
BY LATE WEDNESDAY WITH STILL BELOW NORMAL CONDITIONS.  
 

 
   
SHORT TERM
 
(THIS EVENING THROUGH TUESDAY)  
ISSUED AT 250 PM CDT MON MAY 22 2017  
 
SHORT TERM FORECAST CONFIDENCE ASSESSMENT...AVERAGE OR FAIR WITH  
MAIN ISSUE THE COVERAGE AND INTENSITY OF LIGHT PRECIPITATION THE  
NEXT 24 HOURS WITH UPPER LOW PARKED OVER THE REGION. THIS MAY IMPACT  
HIGHS BY 3 PLUS DEGREES AND LOW RISK OF LOCALIZED RAIN AMOUNTS OVER  
A QUARTER INCH NOT OUT OF THE QUESTION OF MOSTLY SHOWERS AND MAYBE  
AN ISOLATED STORM.  
 
TONIGHT...SKIES TO BE GENERALLY MOSTLY CLOUDY TO CLOUDY WITH POSSIBLY  
AREAS OF LIGHT RAIN AND RAINSHOWERS DEVELOPING TOWARD DAYBREAK AND  
MAYBE SOME AREAS OF FOG FOR LATER SHIFTS TO ASSESS. MINS SHOULD BE  
NEAR 50F FAR NW TO THE MID 50S SE SECTIONS. MOST LOCATIONS SHOULD RECEIVE  
RAIN AMOUNTS WELL BELOW A QUARTER OF INCH.  
 
TUESDAY...CONTINUED CLOUDY AND GOOD CHANCE OF RAIN AND MAYBE AN ISOLATED  
STORM WITH UPPER LOW PRESSURE NEARBY. AREAS OF LIGHT FOG MAY LAST UNTIL  
THE LATE MORNING WITH RAIN TOTALS MOSTLY LIGHT WITH SOME RAIN TOTALS  
OVER A QUARTER OF AN INCH MAINLY EAST OF THE MISSISSIPPI RIVER. HIGHS  
DEPENDING ON RAIN COVERAGE MOSTLY IN THE MID TO UPPER 60S WHICH WILL  
BE 10 PLUS DEGREES BELOW NORMAL MOST AREAS.  
   
LONG TERM
 
(TUESDAY NIGHT THROUGH MONDAY)  
ISSUED AT 250 PM CDT MON MAY 22 2017  
 
THERE IS A PERSISTENT SIGNAL INDICATING TEMPERATURES AT OR BELOW  
NORMAL AND UNSETTLED WEATHER CONDITIONS THROUGH THE END OF THE MONTH.  
 
TUESDAY NIGHT AND WEDNESDAY THE UPPER LEVEL LOW WILL SLOWLY MOVE  
THROUGH THE AREA PRODUCING SHOWERS AND POSSIBLY SOME THUNDERSTORMS.  
RAINFALL SHOULD BE LIGHT BUT COULD APPROACH ONE HALF INCH IN  
THUNDERSTORMS.  
 
WEDNESDAY NIGHT THE UPPER LEVEL LOW MOVES INTO THE OHIO VALLEY. RAIN  
WILL END FROM WEST TO EAST DURING THE EVENING WITH DRY CONDITIONS  
AFTER MIDNIGHT.  
 
QUIET AND DRY CONDITIONS WILL BE SEEN ACROSS THE AREA ON THURSDAY AS  
HIGH PRESSURE MOVES THROUGH THE MIDWEST. TEMPERATURES WILL AVERAGE  
SLIGHTLY BELOW NORMAL.  
 
THURSDAY NIGHT ON...  
 
THURSDAY NIGHT A WEAK UPPER LEVEL DISTURBANCE WILL MOVE THROUGH THE  
AREA. MOISTURE IS LIMITED AND THERE ARE QUESTIONS REGARDING THE  
OVERALL DEPTH OF THE DRY AIR. THE MODEL CONSENSUS HAS SLIGHT CHANCE  
POPS ACROSS MOST OF THE AREA AFTER MIDNIGHT.  
 
FRIDAY AND FRIDAY EVENING THE NEXT STORM SYSTEM WILL MOVE THROUGH  
THE MIDWEST. THERE ARE DIFFERENCES BETWEEN THE MODELS REGARDING THE  
TIMING AND TRACK OF THIS SYSTEM. THE CMC GLOBAL IS MORE AGGRESSIVE  
IN GENERATING PRECIPITATION THAN THE GFS. THE ECMWF IS FURTHER SOUTH  
AND KEEPS THE AREA DRY UNTIL LATE FRIDAY NIGHT.  
 
RIGHT NOW THE MODEL CONSENSUS HAS CHANCE TO LIKELY POPS FRIDAY WITH  
THE HIGHER POPS SOUTH OF I-80. FRIDAY EVENING THE MODEL CONSENSUS  
HAS SLIGHT CHANCE TO CHANCE POPS EAST OF THE MISSISSIPPI AND THEN  
DRY CONDITIONS AFTER MIDNIGHT.  
 
SATURDAY THROUGH MONDAY THE MODEL SOLUTIONS DIVERGE EVEN FURTHER.  
THERE IS A VERY LOOSE AGREEMENT ON AN UPPER LEVEL LOW SLOWLY  
ROTATING ACROSS THE AREA BUT THERE ARE DISAGREEMENTS ON ITS  
STRENGTH, TRACK, AND OVERALL TIMING. ADDITIONALLY, EACH MODEL HAS  
SEVERAL SMALLER DISTURBANCES IN THE FLOW ROTATING AROUND THE UPPER  
LOW OF VARYING STRENGTH.  
 
AS A RESULT, THE MODEL CONSENSUS HAS DRY CONDITIONS SATURDAY  
MORNING, THEN SLIGHT CHANCE TO CHANCE POPS SATURDAY AFTERNOON/NIGHT.  
SUNDAY THROUGH MONDAY THE MODEL CONSENSUS HAS SLIGHT CHANCE TO  
CHANCE POPS FOR EACH DAY.  
 

 
   
AVIATION
 
(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)  
ISSUED AT 1119 PM CDT MON MAY 22 2017  
 
VFR CONDITIONS WILL CONTINUE THIS EVENING, WITH MID CLOUDS  
REMAINING OVER THE AREA. SHOWERS WILL REMAIN NORTH OF HIGHWAY 20  
AND SOUTH OF HIGHWAY 34 MOST OF THE NIGHT. THE MAINLY DRY  
CONDITIONS OVERNIGHT WILL GIVE WAY TO POSSIBLE MVFR CONDITIONS  
MONDAY MORNING, BUT LOOKING AT THE CONDITIONS UPSTREAM, MODELS ARE  
GREATLY OVER DOING THE LOW LEVEL SATURATION, AND THERE ARE MAINLY  
VFR CONDITIONS ASSOCIATED WITH THE UPPER LOW IN WESTERN  
IOWA/EASTERN NE/SD THAT WILL IMPACT THIS AREA TOMORROW. THE MAIN  
RAIN EVENT MONDAY SHOULD IN ILLINOIS, WITH MVFR CONDITIONS IN RAIN  
EXPECTED TO ACCOMPANY IT. FOR NOW, WILL ADD THIS TO MLI AND BRL  
DURING THE AFTERNOON, AND ADD VFR LIGHT RAIN FARTHER NORTHWEST.  
ERVIN  
 

 
   
DVN WATCHES/WARNINGS/ADVISORIES
 
 
IA...NONE.  
IL...NONE.  
MO...NONE.  

 
 

 
 
UPDATE...ERVIN  
SYNOPSIS...NICHOLS  
SHORT TERM...NICHOLS  
LONG TERM...08  
AVIATION...ERVIN  
 
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