158  
FXUS63 KDVN 290434  
AFDDVN  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE QUAD CITIES IA IL  
1134 PM CDT TUE MAR 28 2017  
   
..AVIATION UPDATE
 
 
   
SYNOPSIS
 
 
ISSUED AT 330 PM CDT TUE MAR 28 2017  
 
18Z SURFACE DATA HAD HIGH PRESSURE FROM THE NORTHERN GREAT LAKES  
INTO THE UPPER MIDWEST WHILE A FRONTAL BOUNDARY RAN FROM NORTH TEXAS  
INTO THE TENNESSEE VALLEY. DEW POINTS WERE IN THE 30S AND 40S FROM  
THE GREAT LAKES INTO THE CENTRAL AND NORTHERN PLAINS WITH 50S AND  
HIGHER FROM THE OHIO VALLEY TO THE GULF COAST.  
 

 
   
SHORT TERM
 
(THIS EVENING THROUGH WEDNESDAY)  
ISSUED AT 330 PM CDT TUE MAR 28 2017  
 
THE QUESTION FOR LATE THIS AFTERNOON AND TONIGHT IS HOW FAR SOUTH  
WILL THE CLEARING GET.  
 
BASED ON SATELLITE TRENDS, THE CLEARING LOOKS TO START CROSSING THE  
WI/IL BORDER AROUND 4 PM AND SLOWLY MOVE SOUTH THROUGH MID-EVENING.  
WHEN HIGHER LEVEL CLOUDS ARE ADDED INTO THE PICTURE, THE CLEARING  
LIGHT SHOULD STOP SHORT OF HIGHWAY 30 DURING THE EVENING WITH CLOUDS  
MOVING BACK IN AFTER MIDNIGHT. WHERE THE CLOUDS DO CLEAR OUT TONIGHT  
LOWS SHOULD BE IN THE MID 30S.  
 
MAINLY DRY CONDITIONS WILL BE SEEN TONIGHT ACROSS THE AREA. THE  
EXCEPTION LOOKS TO BE SCOTLAND COUNTY MISSOURI WHERE SPRINKLES OR  
VERY LIGHT RAIN MAY MOVE INTO THE AREA JUST PRIOR TO SUNRISE.  
 
ON WEDNESDAY, RAIN WILL DEVELOP AND OVERSPREAD THE AREA FROM  
SOUTHWEST TO NORTHEAST DURING THE DAY. CLOUD COVER AND THE RAIN WILL  
DICTATE HOW WARM IT GETS BUT MUCH OF THE AREA WILL REMAIN BELOW 50  
DEGREES FOR A HIGH TEMPERATURE.  
   
LONG TERM
 
(WEDNESDAY NIGHT THROUGH NEXT TUESDAY)  
ISSUED AT 330 PM CDT TUE MAR 28 2017  
 
WEDNESDAY NIGHT AND THURSDAY...WARM MOIST CONVEYOR FED UP BY  
SOUTHERLY 30-40+ KT LLJ, STILL APPEARS ON TRACK TO FUEL A MODERATE  
TO LOCALLY HEAVY ELEVATED RAIN EVENT WED NIGHT INTO THU MORNING.  
PROJECTED PWAT FEED OF 0.80 TO NEAR 1.2 INCHES, AND ROUNDS OF LIFT  
COULD WRING OUT WIDESPREAD 0.75 TO 1.25 INCHES OF RAIN BY THU  
AFTERNOON...WITH LOCALIZED SWATHS OF 1.5 TO 2 INCHES POSSIBLE. WE  
SHOULD BE ABLE TO TAKE THOSE KIND OF AMOUNTS IF THEY FALL IN 12-18  
HOURS WITH MINIMAL FLOOD THREAT, BUT DO EXPECT WITHIN BANK RISES ON  
AREA RIVERS AND STREAMS. ALSO PONDING OF WATER ON ROADS AND  
DRAINAGE DITCHES.  
 
CONVERGENT NOSE OF THE ORGANIZING H85 MB JET AND FCST SOUNDING-  
PROJECTED MID LAYER MUCAPES OF 150 TO NEAR 400 J/KG SUPPORT EMBEDDED  
THUNDERSTORMS TOMORROW NIGHT ROOTED AT THE H85-H825 MB LAYER. THERE  
APPEARS ENOUGH STORM LAYER SHEAR TO SUPPORT AT LEAST SOME SMALL  
HAIL WITH THE MORE ORGANIZED CORES ALOFT ESPECIALLY WITH INITIAL  
STORMS WED EVENING. THEN BLOCKED, NEAR VERTICALLY STACKED AND  
POSSIBLY MULTI-CENTER CYCLONE COMPLEX ACRS MO INTO CENTRAL IL TO TRY  
AND "IN-WHIRL" A NARROW DRY SLOT(OR SLOTS) FROM THE SOUTHERN PLAINS,  
WHICH COULD MAKE FOR A FEW MORE BANDS OF ELEVATED STORMS AT TIMES ON  
THEIR LEADING EDGE DURING THE DAY ON THU ESPECIALLY ACRS THE  
SOUTHEASTERN HALF OF THE CWA. SFC TEMPS TO SUFFER UNDER RATHER SHARP  
AND LLVL INVERSION THU WITH MOST HIGHS ONLY IN THE 40S TO LOW 50S.  
CLOSED BLOCKED LOW TO SLOWLY WANDER EAST ACRS CENTRAL IL INTO IN THU  
NIGHT INTO FRI MORNING, WITH WRAP AROUND RAIN WANING AS THE NIGHT  
PROGRESSES. WILL STILL BANK ON A BRISK NORTHEASTERLY BREEZE ON  
NORTHWESTERN FLANK/PRESSURE GRADIENT OF THE LOW THU NIGHT TO MIX OUT  
ANY DENSE FOG POTENTIAL. LINGERING PRECIP STAYS ALL LIQUID INTO FRI  
MORNING.  
 
FRIDAY...THIS DAY COULD BE A RATHER RAW ONE IF WRAP-AROUND CLOUDS  
MAINTAIN WITH NO AFTERNOON BREAK IN SUBSIDENCE WAKE OF EASTWARD  
MIGRATING/FILLING LOW PRESSURE SYSTEM. BRISK NORTH TO NORTHEAST SFC  
WINDS AND HIGHS HELD IN THE 40S. AT LEAST THE LATEST MEDIUM RANGE  
MODELS HAVE TRENDED DRY FOR THE DAY, AND IF WE GET SOME AFTERNOON  
BREAKS MORE SITES TO NEAR 50 DEGREES. LIGHTER WINDS AND CLEARING  
UNDER BOTH SFC AND UPPER RIDGING REGIMES WILL MAKE FOR A SEASONABLY  
CHILLY NIGHT FRI NIGHT WITH LOWS IN THE LOW TO MID 30S...CLOSE TO  
NORMAL FOR APRIL 1ST.  
 
SATURDAY AND SUNDAY...WHILE THE NEXT CYCLONE LURKS ACRS THE SOUTHERN  
PLAINS, FEEL RIDGING WILL MAKE FOR A DRY DAY FOR MOST OF SAT WITH  
MAYBE JUST SOME INCREASING CLOUD COVER FROM THE WEST AS THE DAY  
PROGRESSES. BREAK IN CLOUD COVER WITH DRY CONDITIONS TO TRANSLATE  
INTO NORMAL HIGHS FOR SAT. LEAD WAVE MAY LEAD TO SOME LIGHT  
OVERRUNNING RAIN OR SPRINKLES SAT NIGHT INTO SUNDAY, BUT EASTERLY  
DRY FETCH FLOW TO BATTLE THIS PROCESS.  
 
MONDAY AND NEXT TUESDAY...LATEST RUN MEDIUM RANGE ENSEMBLES SUGGEST  
THE MAIN PIECE OF UPPER WAVE ENERGY TO ROLL OUT ALONG AND SOUTH,  
THEN SOUTHEAST OF THE CWA MON INTO TUE, LIKE SEVERAL OF IT'S  
PRECURSOR CYCLONE SYSTEMS. THUS ANOTHER WET PERIOD ON THE  
NORTHWESTERN FLANK OF THIS SYSTEM TO START THE WORK WEEK OFF WITH,  
BUT CONFIDENCE STILL MARGINAL WITH RUN-TO-RUN MODEL GYRATIONS.  
MODEL LOADED/GUIDANCE HIGHS LOOK TOO MILD FOR MON INTO TUE IF WE GET  
AFFECTED BY THIS SYSTEM. ..12..  
 

 
   
AVIATION
 
(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)  
ISSUED AT 1130 PM CDT TUE MAR 28 2017  
 
GENERALLY MVFR CONDITIONS THROUGH THE PERIOD EXCEPT PERIODS OF HIGH  
SKIES AND VFR CONDITIONS AT DBQ/CID/MLI TERMINALS MUCH OF THE OVERNIGHT  
HOURS. CLOUD BASES WILL BE LOWER TO MVFR BY MORNING AND BY AFTERNOON  
AS RAIN MOVES IN ALONG WITH 1-4 MILES IN RAIN AS A STORM SYSTEM MOVES  
IN FROM THE SOUTH.  
 

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

 
 

 
 
SYNOPSIS...08  
SHORT TERM...08  
LONG TERM...12  
AVIATION...NICHOLS  
 
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