627  
FXUS63 KDVN 240514  
AFDDVN  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE QUAD CITIES IA IL  
1114 PM CST TUE JAN 23 2018  
   
..AVIATION UPDATE
 
 
   
SYNOPSIS
 
 
ISSUED AT 325 PM CST TUE JAN 23 2018  
 
LATEST SFC ANALYSIS WAS INDICATING ONGOING CYCLONIC PRESSURE  
GRADIENT DRIVING BRISK NORTHWEST WINDS ACRS THE REGION, WITH RIDGING  
AND LIGHTER WIND REGIME LOCATED UPSTREAM ACRS THE PLAINS. CURRENT  
WATER VAPOR LOOP WAS INDICATING A VORT MAX/UPPER WAVE CENTERED ACRS  
SD, DIGGING SOUTHEASTWARD TOWARD IA. UPPER RIDGE TO FOLLOW THIS  
SYSTEM FOR THE MIDWEEK, WITH ANOTHER FRONTAL SYSTEM/UPPER TROF  
PUSHING TOWARD THE REGION FROM THE WEST AT THE START OF THE WEEKEND.  
 

 
   
SHORT TERM
 
(THIS EVENING THROUGH WEDNESDAY)  
ISSUED AT 325 PM CST TUE JAN 23 2018  
 
TONIGHT...BRISK NORTHWEST SFC WINDS WILL CONTINUE TO COOL ADVECT OFF  
MN/NW IA SNOW FIELDS, UNTIL THEY RELAX SOME LATER TONIGHT AS THE  
RIDGE SLIDES INTO WESTERN IA. THE CLOUD COVER WILL BE A CHALLENGE  
TONIGHT, AS THE CURRENT STRATOCU FIELDS OVERHEAD LOOK TO GET TRAPPED  
UNDER H85-H8 MB INVERSION AT THE SAME TIME BATTING IN-WRAPPING  
SUBSIDENCE FIELDS OUT OF MN/WI. ALTHOUGH FEEL THERE WILL BE BREAKS AT  
TIMES, WILL PLAY IT MOSTLY CLOUDY. VARYING CLOUD COVER, WIND SPEEDS  
AND LACK OF SNOW COVER WILL ALSO MAKE FOR A LOW TEMP CHALLENGE  
TONIGHT, AND WILL USE A MIDDLE OF THE ROAD BLEND WHICH SUGGESTS MOST  
OF THE AREA TO STAY UP IN THE UPPER TEENS TO LOW/MID 20S THROUGH  
EARLY WED MORNING. MORE OF A CLEAR OUT THAN EXPECTED, AND SFC WIND  
DROP OFF COULD FOSTER COLDER LOWS THAN FCST IN SPOTS. THEN THE NEXT  
FCST CHALLENGE WILL BE IF THE INCOMING UPPER VORT MAX CAN WRING OUT  
FLURRIES OR EVEN LIGHT SNOW LATE TONIGHT. LOOKING UPSTREAM AT SOME  
RADAR RETURNS ACRS CENTRAL NEBRASKA INTO FAR EASTERN SD, AND THE  
POTENTAIL OF SECONDARY LAYER STRATOCU ACTING AS A SEEDER FEEDER,  
WILL KEEP THE FLURRIES GOING AFTER MIDNIGHT, AND EXPAND THEM INTO  
THE 12Z-15Z WED PERIOD IN THE EAST FOR NOW. WOULD NOT BE SURPRISED  
IF A SNOW BAND PUT A LOCALIZED DUSTING DOWN SOMEWHERE, BUT FOR NOW  
WILL KEEP IT MORE FLURRY WORDING.  
 
WEDNESDAY...THIS DAY COULD RANGE FROM A MIX OF CLOUDS AND SUN EARLY,  
TRENDING TO MORE SUNSHINE IN THE AFTERNOON LIKE WHAT IS OCCURRING  
ACRS THE NORTHWESTERN PLAINS ATTM. MORE SUN IN THE AFTERNOON  
SUPPORTS THE FCST HIGHS OF LOW 30S IN THE NORTH, TO THE UPPER  
30S/NEAR 40 IN THE SOUTH. SLIDING SFC RIDGE OVERHEAD WILL MAKE FOR  
LIGHTER SFC WIND REGIME DURING THE DAY AS WELL. ..12..  
   
LONG TERM
 
(WEDNESDAY NIGHT THROUGH NEXT TUESDAY)  
ISSUED AT 325 PM CST TUE JAN 23 2018  
 
FORECAST FOCUS ON ABOVE NORMAL TEMPERATURES WITH MAINLY DRY  
CONDITIONS.  
 
THE REMAINDER OF THE WORK WEEK: UPPER FLOW GRADUALLY BECOMES ZONAL  
ALLOWING FOR A WARMING TREND. HIGH PRESSURE RIDGE WILL BE ACROSS THE  
SOUTHERN STATES BLOCKING THE GULF MOISTURE. THEREFORE, NO  
PRECIPITATION. HIGHS SHOULD BE IN THE 30S TO AROUND 40 ON WEDNESDAY,  
WARMING INTO THE 50S ON FRIDAY.  
 
FRIDAY NIGHT THROUGH MONDAY: A COOLING TREND AGAIN AS A DEEPENING  
CLIPPER SYSTEM TRACKS EAST ALONG THE UNITED STATES/CANADA BORDER.  
THIS WILL BUCKLE THE JET RETURNING A NORTHWEST FLOW AND COLDER  
TEMPERATURES AGAIN. IN THE TRANSITION, A COLD FRONT ARRIVES LATE  
FRIDAY NIGHT INTO SATURDAY BUT MODELS ARE NOT IN AGREEMENT WITH QPF.  
THE GFS/CANADA SUGGESTS A DRY FROPA AND THE EUROPEAN MODEL IS  
TRENDING DRIER ALSO. HIGHS WILL COOL DOWN INTO THE 30S WITH LOWS IN  
THE TEENS TO LOWER 20S, BUT THIS IS STILL ABOVE NORMAL FOR LATE  
JANUARY, AS THE ARCTIC AIR REMAINS BOTTLED UP IN CANADA.  
 
HOWEVER, THERE ARE TELECONNECTIONS THAT THE ARCTIC AIR WILL BE  
PLUNGING SOUTHWARD INTO THE MIDWEST EARLY FEBRUARY, AS THE AO/NAO  
ANOMALIES GO SHARPLY NEGATIVE. THE GFS/ECMWF ARE SUGGESTING THIS TO  
OCCUR EITHER JANUARY 31 OR FEBRUARY 1 WITH A STRONG ARCTIC COLD  
FRONT ARRIVING. APPEARS TO BE A RAIN CHANGING TO ACCUMULATING SNOW  
SCENARIO WITH A RAPID DROP IN TEMPERATURE BEHIND THE FRONT, ALONG  
WITH STRONG WINDS. IF THE EUROPEAN IS CORRECT BRUTALLY COLD AIR WILL  
FOLLOW WITH A POCKET OF -26C 850 MB TEMPERATURES DROPPING INTO  
EASTERN IOWA. OF COURSE, HOW MUCH SNOW COVER WE HAVE WILL BE KEY TO  
HOW COLD IT ACTUALLY GETS. STAY TUNED!  
 
HAASE  
 

 
   
AVIATION
 
(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)  
ISSUED AT 1112 PM CST TUE JAN 23 2018  
 
MVFR CONDITIONS TO PREVAIL TONIGHT WITH CEILINGS OF MOSTLY 2-3K AGL  
WITH SLOWLY CLEARING SKIES TOWARD MORNING INTO THE MID MORNING HOURS.  
THEN FAIR SKIES AND VFR TO PREVAIL WEDNESDAY WITH NORTHWEST TO WEST  
WINDS AT 5 TO 10 MPH AS HIGH PRESSURE MOVE EAST, SHIFTING TO THE SOUTH  
BY DUSK.  
 

 
   
HYDROLOGY
 
 
ISSUED AT 325 PM CST TUE JAN 23 2018  
 
HAVE ISSUED A FLOOD WATCH FOR THE ROCK RIVER AT COMO DUE TO RUNOFF  
FROM RECENT RAINFALL AND ICE ACTION. SIGNIFICANT RISES HAVE OCCURRED  
SINCE MONDAY MORNING. THE RIVER IS SOLID ICE NEAR THE I-88 BRIDGE  
BUT IS FLOWING PRETTY GOOD WITH SOME ICE WHERE THE GAGE IS. THE  
RIVER IS FORECAST TO REACH FS WEDNESDAY MORNING AND GO INTO MINOR  
FLOOD BUT CONFIDENCE IS LOW AT THIS TIME DUE TO ICE CONDITIONS AND  
AMOUNT OF ROUTED FLOW FROM UPSTREAM. THERE IS THE POTENTIAL FOR  
RAPID FLUCTUATIONS OF 1 TO 3 FEET DEPENDING ON ICE ACTION.  
 
ON THE IOWA RIVER AT MARENGO THERE IS AN ICE JAM WHERE THE WATER ON  
THE SURFACE HAS STOPPED FLOWING AND THE RIVER IS FULL OF ICE. DUE TO  
ICE ACTION, RAPID FLUCTUATIONS OF 1 TO 3 FEET IS POSSIBLE. WHILE NO  
FLOOD WATCH OR WARNING IS IN EFFECT AS OF THIS WRITING, WE WILL  
CONTINUE TO MONITOR THE SITUATION.  
 
LITTLE IF ANY ADDITIONAL PRECIPITATION IS EXPECTED FOR ABOUT THE  
NEXT 7 DAYS.  
 
HAASE  
 

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

 
 

 
 
SYNOPSIS...12  
SHORT TERM...12  
LONG TERM...HAASE  
AVIATION...NICHOLS  
HYDROLOGY...HAASE  
 
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