963  
FXUS63 KDVN 191750  
AFDDVN  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE QUAD CITIES IA IL  
1250 PM CDT FRI OCT 19 2018  
   
..AVIATION UPDATE
 
 
   
SYNOPSIS
 
 
ISSUED AT 242 AM CDT FRI OCT 19 2018  
 
EARLY THIS MORNING THE LOCAL AREA WAS IN AN AREA OF WEAK RIDGING  
UPSTREAM OF A SHORTWAVE TROUGH WITH ITS AXIS FROM NORTHERN  
MINNESOTA INTO COLORADO. SCATTERED SHOWERS WERE OBSERVED AHEAD OF  
THIS SYSTEM FROM EASTERN NEBRASKA INTO NORTHEAST MINNESOTA. A  
SECONDARY AREA OF PRECIPITATION WAS OBSERVED FROM OKLAHOMA INTO  
EASTERN KANSAS ASSOCIATED WITH A WING OF MOISTURE TRANSPORT AND  
WARM AIR ADVECTION. CLOUD COVER, 10 MPH WINDS, AND WARM AIR  
ADVECTION OVERNIGHT HAVE ALLOWED TEMPERATURES TO STAY MILD  
OVERNIGHT, WITH READINGS IN THE 40S AND LOW 50S AT 08Z.  
 

 
   
SHORT TERM
 
(TODAY AND TONIGHT)  
ISSUED AT 242 AM CDT FRI OCT 19 2018  
 
THE ELONGATED SHORTWAVE TROUGH OUT TO THE WEST WILL MOVE THROUGH  
THE AREA TODAY. THIS WILL BRING SCATTERED TO WIDELY SCATTERED  
SHOWERS TO MUCH OF THE FORECAST AREA THIS MORNING AND EARLY  
AFTERNOON. AS THE SHORTWAVE MOVES THROUGH, THE MOST AMPLIFIED AREA  
WILL MOVE ACROSS SOUTHERN MINNESOTA AND NORTHERN IOWA INTO  
WISCONSIN AND NORTHERN ILLINOIS. THIS AREA IS ALSO ASSOCIATED WITH  
THE LEFT ENTRANCE REGION OF THE UPPER LEVEL JET STREAK SO LIFT  
SHOULD BE SUFFICIENT FOR WIDESPREAD SHOWERS. THE MOISTURE HOWEVER  
IS LIMITED AND WILL BE VERY NARROW AHEAD OF THE SHORTWAVE. FOR  
INSTANCE, MODELS ARE SHOWING THE DEEP LAYER MOISTURE WILL PUSH  
ACROSS THE AREA IN A 3 HOUR TIME-SPAN. WHILE MOISTURE HAS BEEN  
ADVECTING IN OVERNIGHT, THE DVN 19.00Z SOUNDING WAS QUITE DRY, PW  
VALUE OF 0.31 INCHES, SO WHEN THE SHOWERS DO COME THROUGH THEY'LL  
HAVE QUITE A BIT OF DRY AIR TO MOVE THROUGH. THIS SHOULD LIMIT ANY  
PRECIPITATION TO LIGHT AMOUNTS, GENERALLY A TENTH OF AN INCH OR  
LESS. FOCUSED THE HIGHEST RAIN CHANCES ACROSS THE NORTHERN PART OF  
THE FORECAST AREA, WHERE THE BEST DYNAMICS WILL BE, BUT WILL  
INCLUDE RAIN CHANCES THROUGHOUT THE FORECAST AREA. CLOUD COVER  
WILL PERSIST FOR A FEW HOURS AFTER THE RAIN EXITS, WHICH COULD  
IMPACT TODAYS TEMPERATURES. WARM AIR ADVECTION WILL BRING 850MB  
TEMPERATURES RANGING FROM 9C TO 13C, BUT WITH CLOUDS PERSISTING  
INTO THE AFTERNOON, DON'T HAVE MUCH CONFIDENCE IN HOW MUCH THE  
SURFACE WILL WARM AND MIX TO TAKE ADVANTAGE OF THE WARMER  
TEMPERATURES ALOFT. ULTIMATELY, KEPT HIGHS A BIT COOLER WHERE  
CLOUDS ARE EXPECTED TO LINGER LONGER, BUT WILL NEED TO KEEP A  
CLOSE EYE ON HOW THE SITUATION EVOLVES AND IF THERE WILL BE A NEED  
TO UPDATE HIGHS AT SOME POINT. WINDS WILL ALSO BE A BIT STRONGER  
TODAY, AS WINDS SHORTLY ABOVE THE SURFACE WILL BE BLOWING AT  
20-35KTS. FORECAST SOUNDINGS WOULD SUGGEST MIXING TO ABOUT 875MB  
SO SHOULD GET SOME PERIODS OF GUSTY CONDITIONS.  
 
THE SHORTWAVE PUSHES EAST FAIRLY QUICKLY, WITH DRY CONDITIONS,  
CLEARING SKIES, COOLER AIR, AND WINDS SHIFTING TO THE WEST-  
NORTHWEST BY FRIDAY EVENING. DON'T EXPECT WINDS TO DROP OFF  
THOUGH, KEEPING THE BOUNDARY LAYER MIXED, SO DESPITE THE COLD AIR  
MOVING INTO THE REGION, (850MB TEMPS 0-2C) ONLY DROPPED LOWS  
SATURDAY MORNING INTO THE UPPER 30S AND 40S.  
   
LONG TERM
 
(SATURDAY THROUGH THURSDAY)  
ISSUED AT 242 AM CDT FRI OCT 19 2018  
 
VERY STRONG WINDS EXPECTED SATURDAY FOLLOWED BY MAINLY BELOW NORMAL  
TEMPERATURES.  
 
SATURDAY  
ASSESSMENT...HIGH CONFIDENCE ON VERY STRONG WINDS. LOW TO MEDIUM  
CONFIDENCE ON PRECIP CHANCES.  
 
A POTENT UPPER LEVEL DISTURBANCE WILL MOVE THROUGH THE AREA ON  
SATURDAY. WHILE THERE ARE SOME MINOR DIFFERENCES ON THE TRACK OF THE  
SYSTEM, VERY STRONG WINDS WILL DEVELOP.  
 
ONCE THE INVERSION BREAKS SATURDAY MORNING, WINDS WILL INCREASE  
SIGNIFICANTLY WITH THE STRONGEST WINDS FROM LATE MORNING THROUGH MID-  
AFTERNOON. SUSTAINED WINDS AROUND 25 MPH SHOULD EASILY BE ACHIEVED  
WITH GUSTS OF 40-45 MPH.  
 
DRY AIR MAY LIMIT THE OVERALL AREAL COVERAGE OF SHOWERS THAT OCCUR  
WITH THE PASSAGE OF THE UPPER LEVEL SYSTEM. HOWEVER, SPRINKLES IF  
NOT ISOLATED TO SCATTERED RAIN SHOWERS SHOULD BE SEEN ACROSS THE  
NORTHEAST HALF OF THE AREA SATURDAY MORNING FOLLOWED BY DRY  
CONDITIONS AND CLEARING SKIES IN THE AFTERNOON.  
 
SATURDAY NIGHT  
ASSESSMENT...HIGH CONFIDENCE  
 
CLEAR AND COLD CONDITIONS WILL BE SEEN ACROSS THE AREA SATURDAY  
NIGHT WITH LOW TEMPERATURES IN THE 20S.  
 
SUNDAY AND SUNDAY NIGHT  
ASSESSMENT...HIGH CONFIDENCE  
 
QUIET AND DRY CONDITIONS WILL BE SEEN WITH TEMPERATURES AVERAGING  
BELOW NORMAL.  
 
MONDAY ON...  
 
MONDAY THROUGH WEDNESDAY  
ASSESSMENT...HIGH CONFIDENCE  
 
DRY CONDITIONS WILL CONTINUE THROUGH THE FIRST HALF OF THE WEEK. A  
DRY FRONTAL PASSAGE WILL OCCUR MONDAY AFTERNOON/EVENING THAT WILL BE  
MARKED WITH ONLY AN INCREASE IN CLOUDS.  
 
WEDNESDAY NIGHT AND THURSDAY  
ASSESSMENT...LOW CONFIDENCE ON PRECIPITATION CHANCES  
 
WEDNESDAY NIGHT RETURN FLOW DEVELOPS ACROSS THE AREA AS HIGH  
PRESSURE MOVES INTO THE OHIO VALLEY. THE GLOBAL MODELS HAVE A STORM  
SYSTEM FORECAST TO MOVE ACROSS THE DEEP SOUTH WHICH SHOULD INTERCEPT  
MOST OF THE RETURN MOISTURE MOVING NORTH.  
 
THE GLOBAL MODELS DISAGREE ON WHEN PRECIPITATION MOVES BACK INTO THE  
AREA. THIS DISAGREEMENT APPEARS TO BE CENTERED AROUND THE STRENGTH  
OF THE HIGH IN THE EASTERN GREAT LAKES/OHIO VALLEY AND THE AMOUNT OF  
DRY AIR PRESENT.  
 
THE GFS KEEPS THE ENTIRE AREA DRY WEDNESDAY NIGHT/THURSDAY WITH NOT  
MUCH IN THE WAY OF PRECIPITATION IN WESTERN IOWA. THE CMC GLOBAL  
KEEPS THE AREA DRY BUT DOES DEVELOP PRECIPITATION ACROSS WESTERN  
IOWA. THE ECMWF ON THE OTHER HAND BRINGS LIGHT PRECIPITATION INTO  
THE THE AREA WEDNESDAY NIGHT/THURSDAY WITH THE HELP OF AN UPPER  
LEVEL DISTURBANCE.  
 
AS A RESULT OF THESE DIFFERENCES, THE MODEL CONSENSUS HAS SLIGHT  
CHANCE TO CHANCE POPS WEDNESDAY NIGHT AND THURSDAY MORNING.  
 

 
   
AVIATION
 
(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)  
ISSUED AT 1245 PM CDT FRI OCT 19 2018  
 
MVFR CEILINGS ALONG A SURFACE TROUGH WILL IMPROVE TO VFR LATE  
AFTERNOON OR EVENING. A REINFORCING COLD FRONT ON SATURDAY WILL  
LEAD TO WINDY CONDITIONS WITH PEAK NW GUSTS NEAR 35 KTS. UTTECH  
 

 
   
HYDROLOGY
 
 
ISSUED AT 1100 AM CDT FRI OCT 19 2018  
 
MINOR TO MAJOR FLOODING CONTINUES ON SEVERAL RIVERS IN EASTERN  
IOWA AND NORTHWEST ILLINOIS. LITTLE, IF ANY, RAINFALL IS EXPECTED  
OVER THE NEXT 7 DAYS. ALL TRIBUTARY RIVERS WILL CONTINUE TO  
SLOWLY FALL.  
 
CORALVILLE LAKE RESERVOIR IS STILL NEAR CREST TODAY NEAR 710.9  
FEET. IT WILL SLOWLY FALL OVER THE NEXT WEEK, REACHING 707 FEET  
LATE NEXT WEEK.  
 
ON THE MISSISSIPPI RIVER, ROUTED FLOW FROM UPSTREAM IS RESULTING  
IN RISES; AND AT SOME LOCATIONS MINOR FLOODING; FROM DUBUQUE TO  
LE CLAIRE. FROM THE QUAD CITIES TO MUSCATINE, SOME RISES WILL BE  
SEEN THROUGH THE WEEKEND, BUT LEVELS WILL REMAIN WITHIN THE  
MODERATE FLOOD CATEGORY. DOWNSTREAM OF MUSCATINE, THIS WILL  
TEMPORARILY DELAY RECESSIONS. RIVER LEVELS WILL REMAIN HIGH INTO  
NEXT WEEK.  
 

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

 
 

 
 
SYNOPSIS...BROOKS  
SHORT TERM...BROOKS  
LONG TERM...08  
AVIATION...UTTECH  
HYDROLOGY...14  
 
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