532  
FXUS63 KDVN 010443  
AFDDVN  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE QUAD CITIES IA IL  
1143 PM CDT FRI SEP 30 2016  
   
..AVIATION UPDATE
 
 
   
SYNOPSIS
 
 
ISSUED AT 300 PM CDT FRI SEP 30 2016  
 
18Z SURFACE DATA HAS HIGH PRESSURE FROM THE UPPER MIDWEST INTO THE  
SOUTHERN PLAINS. AN INVERTED TROF RAN FROM A LOW IN CENTRAL INDIANA  
BACK INTO NORTHEAST IOWA. DEW POINTS WERE IN THE 50S FROM THE GREAT  
LAKES INTO THE PLAINS WITH POCKETS OF 60 DEW POINTS IN THE OHIO  
VALLEY.  
 

 
   
SHORT TERM
 
(THIS EVENING THROUGH SATURDAY)  
ISSUED AT 300 PM CDT FRI SEP 30 2016  
 
LATE THIS AFTERNOON AND TONIGHT PATCHY DRIZZLE WITH ISOLATED LIGHT  
RAIN SHOWERS WILL BE SEEN ACROSS THE AREA. THE PERSISTENT LOW CLOUDS  
WILL KEEP TEMPERATURES ABOVE NORMAL TONIGHT WITH READINGS IN THE MID  
AND UPPER 50S.  
 
ON SATURDAY, THE UPPER LOW OVER NORTHERN KENTUCKY WILL DRIFT NORTH  
INTO INDIANA. DISTURBANCES ROTATING AROUND THIS UPPER LOW WILL KEEP  
PATCHY DRIZZLE ALONG WITH SCATTERED LIGHT RAIN SHOWERS ACROSS THE  
AREA. TEMPERATURES ON SATURDAY WILL BE IN THE LOW TO MID 60S.  
   
LONG TERM
 
(SATURDAY NIGHT THROUGH FRIDAY)  
ISSUED AT 300 PM CDT FRI SEP 30 2016  
 
THE LONG TERM WILL FOCUS ON AN APPROACHING UPPER TROF AND SEASONALLY  
STRONG COLD FRONT ARRIVING BY MID WEEK. PRIOR TO THE FRONTS ARRIVAL,  
HIGH PRESSURE WILL BE IN CONTROL FROM SUNDAY THROUGH TUESDAY, WITH  
SOUTHERLY FLOW AND MODERATION BEING THE MAIN THEME THROUGH THE EARLY  
WEEK. AMONG THE WEEKEND DAYS, SUNDAY IS THE CLEAR WINNER HERE WITH  
LIGHT WIND FLOW AND SUNSHINE RESULTING IN A VERY PLEASANT DAY IN THE  
LOWER 70S.  
 
BY SUNDAY NIGHT, THE LARGE HIGH PRESSURE REPLACING THE UPPER LOW IN  
THE GREAT LAKES WILL BE IN PLACE. THIS WILL SET THE STAGE FOR LARGE  
DIURNAL RANGES THROUGH MONDAY NIGHT, AS HIGHS REACH THE LOWER TO MID  
70S AND LOWS FALL TO THE UPPER 40S TO MID 50S.  
 
THE FRONT IS WELL FORECAST BY MODELS TO ARRIVE BY TUESDAY NIGHT IN  
CENTRAL IOWA, AND EXIT THE AREA BY THURSDAY AFTERNOON. HOWEVER, THE  
MOISTURE RETURN AND FORCING ARE VERY INCONSISTENTLY FORECAST. THE  
GFS AND GEM SHOW A THIN BAND OF MOISTURE AND FORCING WITH THE FRONT,  
WITH UPPER FORCING WELL NORTHWEST OF IOWA. THUS THEY REPRESENT A  
VERY TYPICAL FALL COLD FRONT, WITH ONLY A MARGINAL CHANCE FOR  
RAINFALL. THE ECMWF CONTINUE TO BE FAR DEEPER WITH THE UPPER TROF  
WEDNESDAY, AND WITH THAT, IT'S MOISTURE RETURN AND FORCING ARE FAR  
MORE ROBUST. THE PREFERENCE BETWEEN THESE SOLUTIONS ARE NOT CERTAIN,  
AND SINCE OUR FORECAST IS A BLEND FOR THE POPS IN ANY CASE, THE 30  
TO 50 PERCENT POPS ARE IN THE RIGHT BALLPARK FOR THIS UNCERTAIN COLD  
FRONTAL EVENT. HIGHS WILL REMAIN MILD THROUGH WEDNESDAY AND THURSDAY  
IN THE 70S, BUT FOLLOWING THE COLD FROPA, HIGHS FRIDAY SHOULD REMAIN  
IN THE 60S BEHIND THE FRONT.  
 
ERVIN  
 

 
   
AVIATION
 
(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)  
ISSUED AT 1142 PM CDT FRI SEP 30 2016  
 
WRAPAROUND CLOUDS FROM A STALLED UPPER LOW PRESSURE SYSTEM WILL KEEP  
ALL THE TERMINALS CLOUDY TO MOSTLY CLOUDY WITH GENERALLY MVFR AND POSSIBLY  
OCCASIONALLY HIGHER END IFR CONDITIONS FROM LOW CEILINGS. A FEW PERIODS  
OF DRIZZLE OR LIGHT RAIN ARE POSSIBLE AND ARE HANDLED OVERNIGHT AS A  
TEMPO GROUP AND THEN VICINITY WORDING AFTERWARDS. WINDS WILL BE NORTHERLY  
AT 5 TO 15 MPH.  
 

 
   
HYDROLOGY
 
 
ISSUED AT 1213 PM CDT FRI SEP 30 2016  
 
MANY AREA RIVERS ARE NEAR CREST NOW, AND WILL BEGIN FALLING WITHIN  
THE NEXT 36 HOURS. THIS IS TRUE FOR ALL OF THE TRIBUTARY RIVERS IN  
FLOOD AT THIS TIME.  
 
WAPSIPINICON...  
THE STAGE AT NEAR DEWITT REMAINS NEAR CREST, AS 13.78 FEET, WHICH  
IS ABOUT THE 4TH HIGHEST CREST ON RECORD. IT SHOULD REMAIN NEAR  
THAT LEVEL THROUGH TONIGHT, AND POSSIBLY SATURDAY BEFORE BEGINNING  
TO FALL QUICKLY.  
 
CEDAR INTO IOWA...  
THE LEVELS REMAIN AT MAJOR FLOOD STAGE FROM NEAR THE CONFLUENCE ON  
DOWNSTREAM. IN ADDITION, IT APPEARS ALL SITES ON THE LOWER IOWA ARE  
NEAR CREST NOW, AND SHOULD ONLY VARY BY A TENTH OR SO THROUGH THE  
CREST TODAY AND TONIGHT.  
 
MISSISSIPPI...  
GENERALLY, THE ROUTED FLOW SUPPORTED DROPPING MOST CRESTS BY ABOUT  
A TENTH TO TWO TENTHS OF A FOOT TODAY. THIS HAS KEPT THE FORECAST  
CONSISTENT WITHIN FLOOD CATEGORY, EXCEPT AT DUBUQUE LD11 WHERE THE  
WARNING IS NOW DROPPED AND AT KEOKUK WERE MODERATE FLOODING IS  
DROPPED TO MINOR FLOODING. MAJOR FLOODING REMAINS FORECAST FOR NEW  
BOSTON, KEITHSBURG, GLADSTONE, AND BURLINGTON.  
 
ERVIN  
 

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

 
 

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