119  
FXUS63 KDVN 161624  
AFDDVN  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE QUAD CITIES IA IL  
1124 AM CDT TUE JUL 16 2019  
   
UPDATE
 
 
ISSUED AT 1123 AM CDT TUE JUL 16 2019  
 
CLOUD COVER IS HELPING TO SUPPRESS TEMPERATURES SO FAR TODAY. THUS  
HAVE LOWERED HIGH TEMPERATURES SOMEWHAT TODAY AND MAY NEED TO  
LOWER THEM FURTHER.  
 
UPDATE ISSUED AT 1015 AM CDT TUE JUL 16 2019  
 
THETA E GRADIENT JUST EAST OF THE QUAD CITIES IN COMBINATION WITH  
WEAK CONVERGENCE HAS INITIATED RAIN SHOWERS ACROSS WHITESIDE AND  
NORTHERN HENRY COUNTIES.  
 
RAP TRENDS INDICATE THE POTENTIAL FOR ADDITIONAL SHOWERS  
DEVELOPING LATE MORNING AND INTO THE AFTERNOON HOURS. IF SAID  
CONVECTION DEVELOPS IT AND THE ASSOCIATED CLOUD CLOVER MAY RESULT  
IN LOWER TEMPERATURES FOR TODAY.  
 
AN UPDATE TO THE FORECAST WILL BE OUT SHORTLY.  
 

 
   
SYNOPSIS
 
 
ISSUED AT 351 AM CDT TUE JUL 16 2019  
 
THE LATEST WATER VAPOR LOOP WAS INDICATING LINGERING BARRY  
CIRCULATION ACRS THE AR/MO BORDER SLOWLY MOVING TOWARD THE NORTHERN  
MO BOOTHEEL REGION. THE LOCAL AREA GENERALLY REMAIN IN BETWEEN THIS  
FEATURE AND ACTIVE NORTHERLY STORM TRACK ACRS THE NORTHERN CONUS.  
CLOUD DEBRIS OFF THESE TWO ACTION ZONES AND WEAKER MIXING PROFILES  
TO MAKE FOR SOME REPRIEVE FROM THE HEAT TODAY, BEFORE IT COMES BACK  
WITH A VENGEANCE BY THE END OF THE WEEK. ALSO, SOME OCCASIONAL  
THUNDERSTORM CHANCES WILL OCCUR ACRS PORTIONS OF THE AREA FROM TODAY  
THROUGH EARLY THU.  
 

 
   
SHORT TERM
 
(TODAY AND TONIGHT)  
ISSUED AT 351 AM CDT TUE JUL 16 2019  
 
TODAY...WITH REMNANT BARRY CIRCULATION/UPPER LOW ON TRACK TO OPEN  
UP AND WEAKEN AS IT DRIFTS OFF TO THE EAST, SCTRD LIGHT SHOWER  
CHANCES WILL CONTINUE MAINLY ALONG AND EAST OF THE MS RVR THROUGH  
MID AFTERNOON BEFORE SHIFTING OFF TO THE EAST. SHOULD BE MAINLY  
SHOWERS, ALTHOUGH SOME MIDDAY INSTABILITY MAY ALLOW FOR SOME  
EMBEDDED THUNDER EVENTUALLY BEFORE THAT ACTIVITY ASSOCIATED WITH  
BARRY WANES.EYES THEN TURN TO A MUCH MORE SUBSTANTIAL POTENTIAL FOR  
THUNDERSTORMS MOVING IN FROM THE WEST THIS AFTERNOON IN THE FORM OF  
A CONVECTIVELY ENHANCED WAVE/MCV ASSOCIATED WITH THE ONGOING STORM  
COMPLEX ACRS CENTRAL INTO EASTERN NE. BEFORE THEN, WILL HAVE TO  
WATCH SCTRD REMNANT STORM CLUSTERS NOW NORTH OF THE DES MOINES AREA  
AS THEY TRY TO MOVE EAST TOWARD THE NORTHWESTERN CWA THIS MORNING.  
MOST CAMS AND HIRES SOLUTIONS DECAY THIS CONVECTION AS IT MOVES EAST  
TOWARD THE LOCAL AREA THIS MORNING, BUT CAN'T TOTALLY TRUST THOSE  
IDEAS. MOST OF THE MODELS ALSO DIURNALLY DECAY THE NEBRASKA STRONG  
STORMS/MCS AS THEY MOVE EASTWARD ACRS WESTERN IA THIS MORNING, BUT  
AGAIN CAN'T TOTALLY ACCEPT THAT IDEA AND THE DAY CREW WILL HAVE TO  
WATCH FOR STORM MAINTENANCE.  
 
EVEN IF THE COMPLEX DECAYS, THE ASSOCIATED MCV WILL LOOK TO KICK UP  
NEW STORM CLUSTERS ACRS CENTRAL AND NORTHERN IA BY EARLY TO MID  
AFTERNOON. WILL THEN WALK SCTRD STORM CLUSTERS INTO THE WESTERN AND  
NORTHWEST CWA BY MID TO LATE AFTERNOON. IF SOME DECAY IN CLOUD  
DEBRIS ALLOWS FOR ENOUGH HEATING AND SBCAPES ATTAINING AT LEAST 2000  
J/KG, THESE STORMS MAY BE MARGINALLY SEVERE WITH DAMAGING WINDS.  
STILL HIGH FREEZING/WBZ LEVELS MAKE LARGE HAIL A SECONDARY THREAT.  
IF A STORM CLUSTER CAN ORGANIZE COLD POOL MECHANICS, MORE  
SIGNIFICANT WIND GUSTS OVER 60 MPH WILL BE POSSIBLE. CONVERGENT  
POOLS OF HIGHER PWATS WILL FUEL LOCALLY HEAVY RAIN UNDER THE PASSING  
STORMS, AND CAN'T RULE OUT A LOCALIZED FLASH FLOOD THREAT FOR A LESS  
PROGRESSIVE STORM OR AREAS THAT GET HIT MORE THAN ONCE.  
 
CLOUD COVER AND ASSOCIATED HEATING/INSTABILITY BUILD UP LIMITS WILL  
BE A CHALLENGE TODAY, WITH PARTLY CLOUDY TO MOSTLY SUNNY SWATHS  
POSSIBLE IN BETWEEN CLOUDS OFF BARRY AND CONVECTIVE DEBRIS FORM THE  
NORTHWEST. WILL GO WITH HIGHS GENERALLY IN THE MID TO UPPER 80S IN  
MOST AREAS, WITH LIGHTER SFC WINDS/LESS MIXING ALLOWING SFC DPTS TO  
MAINTAIN IN THE MUGGY UPPER 60S TO LOWER 70S.  
 
TONIGHT...MOST MODELS THAT HAVE THE LATE AFTERNOON INTO EVENING  
STORMS IN OUR WEST HALF THEN DECAY THEM AS THEY PROPAGATE EASTWARD  
TOWARD THE MS RVR AROUND 9-10 PM OR SO. THEY DO SO PROBABLY  
ENCOUNTERING LESS UNSTABLE AIR AND LINGERING SUBSIDENCE BEHIND  
DEPARTING BARRY CIRCULATION. BUT AGAIN CAN'T TOTALLY TRUST THESE  
TRENDS BUT WILL DECREASE POPS FROM WEST-TO-EAST AFTER MIDNIGHT. LATE  
NIGHT MCS GENERATION GROUNDS LOOK TO OCCUR ACRS SD/NE AND THE  
WESTERN MN-IA AREAS, WITH JUST A LOW CHANCE FOR SOME OF THIS  
ACTIVITY MAKING IT DOWN INTO THE NORTHWESTERN CWA BEFORE 12Z WED.  
..12..  
   
LONG TERM
 
(WEDNESDAY THROUGH MONDAY)  
ISSUED AT 351 AM CDT TUE JUL 16 2019  
 
EXCESSIVE HEAT WATCH REMAINS IN EFFECT FROM WED PM THROUGH SAT,  
AS PROLONGED/MULTI-DAY PERIOD OF DANGEROUS HEAT STILL ON  
TRACK DURING THIS TIMEFRAME. SOME UNCERTAINTY EXISTS WITH  
TEMPERATURES ON WED DUE TO POTENTIAL FOR A FEW STORMS AND DEBRIS  
CLOUDINESS IN SOME AREAS. THERMAL PARAMETERS HOWEVER, WOULD  
EASILY SUPPORT HIGHS IN LOWER 90S WITH PERIODS OF SUN, WHICH  
COMBINED WITH DEW POINTS IN THE 70S WOULD YIELD MAX HEAT INDEX  
READINGS AROUND 100. THIS HEAT WILL ONLY INTENSIFY DURING THU-SAT  
PERIOD, AS THE LOW TO MID LEVEL THERMAL RIDGE OVERSPREADS THE  
AREA. ASSOCIATED 850 HPA TEMPERATURES ARE FORECAST AROUND 25C BY  
GFS AND EC, WHICH SHOULD TRANSLATE TO WIDESPREAD HIGHS IN THE MID  
TO UPPER 90S WITH POSSIBLY A COUPLE FAVORED HOT SPOTS TOPPING THE  
CENTURY MARK. FORECAST DEW POINTS IN THE MID 70S COULD BE A BIT  
AGGRESSIVE, AS WINDS WILL BE GUSTY BOTH THU-FRI WITH AFTERNOON  
MIXING LIKELY DRAWING THEM DOWN A BIT. ALL THIS MAY DO THOUGH IS  
ALLOW TEMPS TO NUDGE EVEN HIGHER IN FAVORABLE MODEST LOW TO MID  
LEVEL SW FLOW. BOTTOM LINE, CONFIDENCE CONTINUES TO INCREASE IN  
MULTIPLE DAYS OF EXCESSIVE HEAT OVER THE LATTER HALF OF THE WEEK  
INTO THE UPCOMING WEEKEND, WITH HEAT INDEX VALUES IN THE 100 TO  
110 DEGREE RANGE. IN ADDITION, IT WILL REMAIN VERY WARM AT NIGHT,  
WITH HEAT INDEX READINGS LIKELY STAYING AT OR ABOVE 75 DEGREES NOT  
ALLOWING FOR MUCH IN THE WAY OF RELIEF. IF TRENDS PERSIST WOULD  
EXPECT THE EXCESSIVE HEAT WATCH TO BE UPGRADED LATER TODAY.  
 
THERE IS SIGNS OF A BREAK IN THE DANGEROUS HEAT BY LATE IN THE  
WEEKEND INTO EARLY NEXT WEEK, AS THE BROAD AND ANOMALOUS UPPER  
RIDGE /HEAT DOME/ IS FLATTENED AND RE-AMPLIFIES OUT WEST AS A  
FAIRLY STRONG TROUGH EJECTS ACROSS THE NORTHERN PLAINS AND UPPER  
MIDWEST. THIS WILL PUSH A COLD FRONT THROUGH THE AREA BRINGING  
RELIEF IN THE FORM OF COOLER AND DRIER AIR. THERE STILL REMAINS  
SOME TIMING DIFFERENCES IN THE GFS, EC AND CANADIAN BUT THE  
GENERAL TIMEFRAME WOULD APPEAR TO BE SAT NIGHT OR SUNDAY.  
 
ASIDE FROM THE HEAT THERE WILL BE SOME STORM CHANCES, ESPECIALLY  
WED-THU AND MOSTLY ACROSS THE NORTH AS IT APPEAR NOW WITH  
POTENTIAL FOR DEVELOPMENT OR PROPAGATION OF CONVECTION INTO THE  
NORTH WITH OUTFLOW OF MN/WI STORMS AND PROXIMITY OF LOW LEVEL JET.  
WOULD HAVE TO MONITOR FOR STRONG GUSTY WINDS AND LOCALLY HEAVY  
RAIN WITH ANY STORMS. ADDITIONAL STORM CHANCES WILL DEVELOP DEEPER  
INTO THE WEEKEND ATTENDANT TO THE COLD FRONTAL PASSAGE.  
 

 
   
AVIATION
 
(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)  
ISSUED AT 610 AM CDT TUE JUL 16 2019  
 
IFR TO EVEN LIFR CIGS HAVE CREPT UP TO ALL TAF SITES, BUT SHOULD  
LAST THE LEAST AMOUNT OF TIME AT DBQ AND CID OVER THE NEXT FEW  
HOURS BEFORE CIGS INCREASE OR BREAK UP. LOW MOISTURE FIELDS OFF  
LINGERING BARRY CIRCULATION WILL KEEP IFR TO LOW MVFR CIGS GOING  
AT MLI AND BRL THROUGH LATE MORNING. A LOW CHANCE FOR CONVECTIVE  
DEBRIS CLOUDS AND POSSIBLE SHOWERS MAKING IT EAST INTO CID THIS  
MORNING, SHOULD CONTINUE TO DECAY AS IT MOVES EAST. OTHER LIGHT  
SHOWERS MAY GET INTO THE EASTERN VCNTY OF BRL THROUGH MIDDAY.  
SOME IMPROVEMENT OF CLOUDS IN ALL AREAS BY AFTERNOON WITH LIGHT  
AND VARIABLE WINDS GENERALLY UNDER 7 KTS. THEN THE WATCH WILL BE  
ON FOR MORE STORM CLUSTERS MOVING IN FROM THE WEST AND GETTING  
INTO THE VCNTY OF CID, DBQ AND POSSIBLY MLI DURING THE LATE  
AFTERNOON AND ESPECIALLY THE EVENING. WILL PLACE SOME VCNTY  
WORDING AT THESE SITES, BUT TIMING STILL UNCERTAIN AND WILL HAVE  
TO BETTER DEFINE A WINDOW AS THE CONVECTIVE ACTIVITY UNFOLDS AND  
DEVELOPS. THESE STORMS MAY BE STRONG DURING THE EVENING WITH  
PASSING BOUTS OF MVFR TO IFR CONDITIONS FROM HEAVY RAIN AND GUSTY  
WINDS. AFTER WHATEVER STORM ACTIVITY CAN DEVELOP AN MOVE THROUGH  
THE TAF SITES, WILL HAVE TO WATCH OUT FOR LATE NIGHT FOG  
DEVELOPMENT OF AT LEAST MVFR EXTENT IN LIGHT TO CALM SFC REGIME  
AND INCREASED SFC MOISTURE LAYER.  
 

 
   
DVN WATCHES/WARNINGS/ADVISORIES
 
 
IA...EXCESSIVE HEAT WATCH FROM WEDNESDAY AFTERNOON THROUGH SATURDAY  
EVENING FOR BENTON-BUCHANAN-CEDAR-CLINTON-DELAWARE-DES  
MOINES-DUBUQUE-HENRY IA-IOWA-JACKSON-JEFFERSON-JOHNSON-  
JONES-KEOKUK-LEE-LINN-LOUISA-MUSCATINE-SCOTT-VAN BUREN-  
WASHINGTON.  
 
IL...EXCESSIVE HEAT WATCH FROM WEDNESDAY AFTERNOON THROUGH SATURDAY  
EVENING FOR BUREAU-CARROLL-HANCOCK-HENDERSON-HENRY IL-JO  
DAVIESS-MCDONOUGH-MERCER-PUTNAM-ROCK ISLAND-STEPHENSON-  
WARREN-WHITESIDE.  
 
MO...EXCESSIVE HEAT WATCH FROM WEDNESDAY AFTERNOON THROUGH SATURDAY  
EVENING FOR CLARK-SCOTLAND.  
 

 
 

 
 
UPDATE...08  
SYNOPSIS...12  
SHORT TERM...12  
LONG TERM...MCCLURE  
AVIATION...12  
 
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