409  
FXUS63 KDVN 261206  
AFDDVN  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE QUAD CITIES IA IL  
706 AM CDT TUE MAR 26 2019  
   
..AVIATION UPDATE
 
 
   
SYNOPSIS
 
 
ISSUED AT 330 AM CDT TUE MAR 26 2019  
 
HIGH PRESSURE IS NOW OVER THE GREAT LAKES, WITH LIGHT EASTERLY FLOW  
TO SOUTHEASTERLY FLOW BECOMING ESTABLISHED OVER IOWA AND ILLINOIS.  
THIS IS SERVING TO PUSH THE LINGERING MID CLOUDS A BIT WEST AND THIN  
THE AXIS AS WELL. IN ALL, DESPITE SOME CIRRUS SPILLING OVER THE  
RIDGE ALOFT, SKIES ARE FINALLY ENTERING INTO A MORE WIDESPREAD CLEAR  
STATUS.  
 

 
   
SHORT TERM
 
(TODAY AND TONIGHT)  
ISSUED AT 330 AM CDT TUE MAR 26 2019  
 
BENIGN WEATHER IS IN STORE TODAY WITH HIGH PRESSURE IN CONTROL.  
LIGHT SOUTHEAST WINDS WITH FULL TO FILTERED SUN WILL HELP BOOST  
HIGHS TO THE UPPER 40S TO LOWER 50S, WITHIN A DEGREE OR TWO OF  
YESTERDAY. WHILE THIS WILL BE A COOL DAY TEMPERATURE WISE, THE  
LIGHT WINDS AND SUN SHOULD PROVIDE A PLEASANT FEEL TO THE DAY.  
 
TUESDAY NIGHT, LIGHT SOUTHEAST WINDS WILL BECOME SOUTH, AND BEGIN TO  
WARM ADVECT. THIS PLUS SOME INCREASED CLOUDS WILL HELP KEEP LOWS UP  
INTO THE LOWER TO MID 30S.  
   
LONG TERM
 
(WEDNESDAY THROUGH MONDAY)  
ISSUED AT 330 AM CDT TUE MAR 26 2019  
 
WEDNESDAY  
 
GUSTY SOUTHERLY WINDS WILL BOOST HIGHS INTO THE LOW TO MID 60S ON  
AVERAGE. FORECAST SOUNDINGS SHOW DAYTIME MIXING INTO 40-50 KT  
850MB SOUTHWEST FLOW WHERE TEMPS ARE NEAR 6-8 C.  
 
WINDS: A LARGE AMOUNT OF DIRECTIONAL SHEAR SHOULD TEMPER THE MAX  
GUSTS A BIT. HOWEVER, THE BOUNDARY LAYER FLOW WILL BECOME MORE  
UNIDIRECTIONAL THROUGH THE AFTERNOON, COINCIDENT WITH THE PERIOD  
OF STRONGEST SURFACE PRESSURE GRADIENT. FOR THESE REASONS, SEE  
POTENTIAL FOR GUSTS AROUND 40 MPH WITH THE FAVORED AREA ACROSS THE  
NORTHWEST CWA -- ROUGHLY ALONG AND NORTH OF A LINE FROM DUBUQUE  
TO CEDAR RAPIDS TO SIGOURNEY. ELSEWHERE, 30-35 MPH CAN BE  
EXPECTED. MAIN IMPACT FROM THE HIGHER GUSTS WOULD BE DIFFICULT  
TRAVEL FOR HIGH PROFILE VEHICLES, ESPECIALLY ON WEST TO EAST  
ROADS.  
 
FIRE WEATHER: IF A GRASSLAND WILDFIRE WERE TO IGNITE WEDNESDAY  
AFTERNOON, IT WOULD SPREAD QUICKLY THROUGH THE CURED/DORMANT  
VEGETATION. ONE LIMITING FACTOR IS MIN RH VALUES BETWEEN 40-50%,  
WHICH ARE TYPICALLY MUCH LOWER ON SIGNIFICANT GRASSLAND WILDFIRE  
DAYS. NO FIRE WEATHER HEADLINES ARE ANTICIPATED AT THIS TIME  
BECAUSE OF THE AVERAGE MIN RH VALUES.  
 
THURSDAY  
 
CONTINUED MILD WITH HIGHS IN THE 60S (MID 50S IN THE FAR NW).  
HAVE SLIGHT CHANCES FOR SHOWERS AND THUNDERSTORMS WEDNESDAY NIGHT  
INTO THURSDAY MORNING, BUT AREAL COVERAGE WITH THIS ACTIVITY LOOKS  
TO BE LOW. STRONGER LARGE SCALE ASCENT AND DEEPER GULF OF MEXICO  
TO MIDWEST WV TRANSPORT IS EXPECTED LATER THURSDAY INTO FRIDAY.  
MODELS FOCUS THE FIRST WAVE OF RAIN IN THE SOUTHERN CWA THURSDAY  
AFTERNOON THROUGH THURSDAY NIGHT.  
 
FRIDAY  
 
A SURFACE WARM FRONT IS FORECAST TO SET UP ALONG THE IOWA AND  
MISSOURI BORDER, EXTENDING EAST INTO WEST-CENTRAL ILLINOIS.  
CONVERGENCE AND FRONTOGENESIS WILL STRENGTHEN ALONG THE  
AFOREMENTIONED FRONT AND SLOPE TO THE NORTH ALOFT OVER THE REST  
OF IOWA AND NORTHERN ILLINOIS.  
 
PRECIPITATION: STRONG FORCING AND SUFFICIENT MOISTURE WITH PWATS  
NEAR 1 INCH MEANS MODERATE TO HEAVY PRECIPITATION IS EXPECTED  
WITH THIS SYSTEM. WPC PLACES THE HEAVIEST QPF AXIS OF 1-2"+ ALONG  
AND SOUTH OF HIGHWAY 30. IF THESE AMOUNTS ARE REALIZED, A RENEWED  
ROUND OF TRIBUTARY RIVER FLOODING WOULD BECOME LIKELY. AND IT  
WOULD BE BAD TIMING FOR ENHANCED TRIBUTARY OUTPUT TO ENTER INTO  
THE MISSISSIPPI RIVER AS THE SNOWMELT CREST IS APPROACHING FROM  
THE NORTH.  
 
MODEL DISCREPANCIES: THE GFS AND ECMWF ARE IN GOOD AGREEMENT ON  
WIDESPREAD PRECIPITATION OF 0.75 - 1.25 INCHES WITH A FEW  
LOCALIZED BAND UP TO 1.50 INCHES, WHICH DOESN'T INCLUDE THE RAIN  
THAT FALLS ON THURSDAY. THE CMC IS MUCH WETTER AND SLIGHTLY  
FURTHER NW WITH THE HEAVIEST QPF AXIS, TAKING IT SQUARELY THROUGH  
THE CWA.  
 
SNOW: THERE MAY BE ENOUGH COLD AIR ON THE BACKSIDE OF THE 850MB  
LOW TO CHANGE RAIN OVER TO SNOW FRIDAY NIGHT. IT'S TOO EARLY TO  
KNOW IF THE SET UP WILL BE RIGHT FOR WET ACCUMULATIONS.  
 
THE WEATHER QUIETS DOWN BEYOND SATURDAY WITH TEMPERATURE RUNNING  
BELOW NORMAL. UTTECH  
 

 
   
AVIATION
 
(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)  
ISSUED AT 654 AM CDT TUE MAR 26 2019  
 
VFR CONDITIONS WILL PREVAIL THROUGH THE NEXT 24 HOURS.  
 

 
   
HYDROLOGY
 
 
ISSUED AT 907 PM CDT MON MAR 25 2019  
 
I HAVE ISSUED AN UPGRADED WARNING FOR BELLEVUE LD12, WITH THE END  
OF THE PERIOD NOW SOLIDLY ABOVE 18 FEET. THIS IS THE LONG TERM  
RISE ARRIVING, AND NOT ASSOCIATED WITH NEW QPF. OTHERWISE, NO  
SIGNIFICANT CHANGES NOTED. RCKI2, THE QUAD CITIES IS NEAR CREST  
AROUND 18.5-18.6 FEET.  
 
WITH JUST MINOR AMOUNTS OF RECENT RAINFALL AND MAINLY DRY WEATHER  
EXPECTED THROUGH WEDNESDAY, ANOTHER RIVER FORECAST CYCLE WITHOUT  
MAJOR CHANGES TODAY. THE CEDAR RIVER AT PALO DROPPED BELOW FLOOD  
STAGE EARLY THIS MORNING, AND THE PECATONICA RIVER AT FREEPORT IS  
CURRENTLY DROPPING BELOW THE FLOOD STAGE. OTHERWISE CONDITIONS  
CONTINUE IMPROVING ON MOST AREA TRIBUTARY RIVERS WITH LEVELS  
SLOWLY FALLING. THAT BEING SAID, THE ROCK RIVER AT MOLINE AND THE  
WAPSI NEAR DE WITT CONTINUE IN THE MAJOR FLOOD STAGE, BUT BOTH ARE  
FALLING AND ARE PROJECTED TO FALL UNDER THE MAJOR CATEGORY LATER  
TONIGHT INTO EARLY TUESDAY MORNING.  
 
MEANWHILE, RISES CONTINUE FROM ROUTED WATER FROM SNOW MELT UP NORTH  
THROUGH THE MAINSTEM MISSISSIPPI RIVER NORTH OF THE QUAD CITIES,  
WITH SEVERAL SITES IN THE MINOR TO MODERATE FLOOD CATEGORY. THIS  
WHILE POINTS TO THE SOUTH OF THE QUAD CITIES ARE EXPERIENCING  
MODERATE TO MAJOR FLOODING. BUT SEVERAL OF THESE SITES FROM THE QUAD  
CITIES ON SOUTHWARD ARE EITHER NEARING A BROAD CREST, OR JUST  
STARTING TO EXIT THE CREST STAGE AND BEGIN TEMPORARY SLOW FALLS  
THROUGH THE END OF THE WEEK. RIVER LEVELS FROM QUAD CITIES ON  
SOUTHWARD, WHILE BEGINNING SLOW FALLS, WILL STILL LARGELY REMAIN  
ABOVE MAJOR FLOOD STAGE THROUGH THE NEXT 7 DAYS AND LIKELY BEYOND  
AIDED BY ONGOING TRIBUTARY INPUT. UPSTREAM OF THE QUAD CITIES LEVELS  
ON THE MISSISSIPPI RIVER WILL CONTINUE RISING THROUGHOUT THE NEXT 7  
DAYS AND BEYOND DUE TO INCREASE IN FLOW FROM SNOWMELT ACROSS  
MINNESOTA AND WISCONSIN. LOCK AND DAM 12 AT BELLEVUE WILL PROBABLY  
NEED TO BE UPGRADED TO A WARNING FOR MODERATE FLOODING SOON WITH  
RISES CONTINUING PAST DAY 7.  
 
THERE WILL LIKELY BE ANOTHER CREST OR CRESTS ALONG THE MISSISSIPPI  
AND ITS TRIBUTARY RIVERS WHEN THE REST OF THE SNOW ACROSS MINNESOTA  
AND WISCONSIN MELTS. WHILE THE TIMING OF THESE POTENTIAL FLOOD  
CRESTS IS UNCERTAIN, THE MOST LIKELY TIME FRAME STILL APPEARS TO BE  
FROM AROUND APRIL 10TH THROUGH THE 25TH. IF TEMPERATURES ACROSS THE  
MIDWEST ARE WARMER THAN THE CURRENT FORECASTS AND OUTLOOKS, THE NEXT  
FLOOD CREST MAY MOVE FORWARD BY 6 TO 10 DAYS. ALSO, ANY HEAVY  
PRECIPITATION IN THE REGION WOULD CAUSE A CHANGE IN TIMING OF THE  
CRESTS AS WELL, OR PRODUCE ADDITIONAL SECONDARY CRESTS. IN  
PARTICULAR, A POTENTIALLY HEAVY PRECIPITATION WINDOW TO BE AWARE OF  
STILL LOOKS TO BE FROM THIS THURSDAY MARCH 28TH, THROUGH SATURDAY  
MARCH 30TH. THERE STILL CONTINUES TO BE UNCERTAINTY ON THE EVENTUAL  
PLACEMENT FROM NORTH TO SOUTH, AS WELL AS THE RAINFALL AMOUNTS ADDED  
UP DURING THIS TIME. THERE ALSO CONTINUES TO BE THE CHANCE THAT THE  
RAIN MAY CHANGE TO SNOW LATER FRIDAY NIGHT INTO SATURDAY IN  
PORTIONS OF THE AREA.  
 

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

 
 

 
 
SYNOPSIS...ERVIN  
SHORT TERM...ERVIN  
LONG TERM...UTTECH  
AVIATION...UTTECH  
HYDROLOGY...ERVIN/12  
 
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