Area Forecast Discussion
Issued by NWS Quad Cities, IA IL

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000
FXUS63 KDVN 262039
AFDDVN

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
339 PM CDT SUN JUL 26 2015

.SYNOPSIS...
ISSUED AT 113 PM CDT SUN JUL 26 2015

UPPER LEVEL SHORTWAVE...ANOMALOUSLY DEEP MOISTURE (CHARACTERIZED
BY PWATS OF NEARLY 2 INCHES OR 1 TO 2 STANDARD DEVIATIONS ABOVE
CLIMO)...AND WEAK STEERING WINDS ALOFT COMBINED TO PRODUCE AREAS
OF HEAVY RAIN (1-2+ INCHES) IN PORTIONS OF NORTHEAST IA AND
NORTHWEST IL. THE HEAVIEST RAINS LIKELY WERE FOUND OVER SOUTHEAST
JACKSON COUNTY WHERE DOPPLER RADAR ESTIMATES OVER 4 TO AROUND 5
INCHES MAY HAVE FELL... LEADING TO SIGNIFICANT FLASH FLOODING
AROUND GREEN ISLAND. THE AFOREMENTIONED SHORTWAVE IS ADVANCING
EASTWARD THROUGH SOUTHERN WI AND NORTHERN IL THIS AFTERNOON...AND
IS AIDING REGENERATION OF SHOWERS AND STORMS OVER NORTHERN IL. AT
19Z... A WELL-DEFINED OUTFLOW BOUNDARY FROM THE MORNING ACTIVITY
ARCS FROM JUST EAST OF MARSHALLTOWN IA...TO JUST SOUTH OF IOWA
CITY...TO NEAR MUSCATINE. A SECOND WELL-DEFINED OUTFLOW FROM
ONGOING ACTIVITY EXTENDS FROM NEAR WALCOTT...TO MOLINE...TO SOUTH
OF GENESEO AND PRINCETON IL AT 19Z. LINGERING COOL POOL COUPLED
WITH CLOUDS AND EASTERLY WINDS HOLDING TEMPS DOWN IN THE 70S
PORTIONS OF NORTHEAST IA AND NORTHERN IL. MEANWHILE...TO THE SOUTH
OF THE BOUNDARIES WHERE MORE SOLAR INSOLATION WAS OCCURRING TEMPS
HAVE WARMED INTO THE LOWER TO MIDDLE 80S. EYEING THESE BOUNDARIES
AS FOCUS FOR SOME CONVECTIVE POTENTIAL LATE THIS AFTERNOON UNTIL
SUNSET. 19Z DVN RAOB HOWEVER...SHOWS STOUT EML IN WAKE OF EXITING
SHORTWAVE WHICH IN ABSENCE OF FORCING SHOULD SUPPRESS ANY DEEP
CONVECTIVE DEVELOPMENT. BUT... WITH FURTHER HEATING MAY BE ABLE TO
ERODE LOWER CAPPING INVERSIONS FOR SOME SHALLOW WEAK LOW TOPPED
CONVECTION ALONG/AHEAD OF OUTFLOW BOUNDARIES OFFERING POTENTIAL
FOR FUNNEL CLOUDS AND POSSIBLY BRIEF SPINNUP OR NON-SUPERCELL
TORNADO WITH ANY BOUNDARY INTERACTION.

OTHERWISE...MAIN STORY IS RETURN OF VERY WARM TO HOT AND HUMID CONDITIONS MONDAY AND
TUESDAY AS UPPER LEVEL RIDGE BUILDS ACROSS THE REGION.

&&

.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 113 PM CDT SUN JUL 26 2015

MAIN FORECAST CONCERN FOR THE SHORT TERM FORECAST WILL BE THE SLOW
MOVING WARM FRONT MOVING THROUGH THE AREA TONIGHT THROUGH MONDAY.
THIS BOUNDARY WILL LIKELY STALL ACROSS THE CWA OR MOVE RATHER
SLOWLY. HAVE MAINTAINED CHC TO SCHC POPS ACROSS MOST THE CWA
THROUGH THE SHORT TERM.

STRONG H5 CAP IS ADVECTING INTO THE AREA AS AN H5 RIDGE MOVES
INTO THE AREA. THIS CAP WILL LIMIT THE OVERALL COVERAGE AND
STRENGTH OF SHOWERS AND THUNDERSTORMS TONIGHT ACROSS THE AREA.
HAVE MAINTAINED SCHC POPS ACROSS THE AREA AS SFC BOUNDARY IS
MILLING AROUND THE AREA. TOMORROW...THE BOUNDARY REMAINS IN PLACE
AS THE H5 RIDGE FIRMLY BUILDS INTO THE AREA. THE SFC BOUNDARY
COULD SEVERE AS A FOCUS FOR THUNDERSTORMS DEVELOPMENT ACROSS THE
AREA. ONLY A SCHC IS FORECAST AS THE RIDGE AND WARM TEMPS WILL
LIKELY INHIBIT MUCH OF THE CONVECTION. TEMPERATURES WILL BE IN
THE MID TO UPPER 80S AND POSSIBLY 90 ACROSS OUR FAR SOUTH. THIS
HEAT AND HUMIDITY LEADS TO BORDERLINE HEAT INDICES IN THE HEAT
ADVISORY CRITERIA RANGE. AT THIS TIME...ONLY ONE HOUR AND TWO
COUNTIES REACH ADVISORY. DECIDED TO HOLD OFF AND BRIEF THE MID
SHIFT AS ANY LINGERING CONVECTION TONIGHT COULD AFFECT THE TEMPS
FOR TOMORROW.

.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 113 PM CDT SUN JUL 26 2015

MAIN FORECAST CONCERN FOR THE LONG TERM ARE THE CHANCES FOR RAIN
AND THE PATTERN SHIFT ON WEDNESDAY. THE BOUNDARY THAT HAD BEEN
OVER THE AREA...REMAINS OVER THE AREA ON TUESDAY AND ACTUALLY IS
PULLED TO THE NORTH AS A WARM FRONT. HOT TEMPERATURES AND HIGH
DEWPOINTS WILL LEAD TO HEAT INDICES THAT MOST LIKELY WILL RESULT
IN A HEAT ADVISORY BEING ISSUED.

STRONG TROF IS FORECAST TO MOVE ACROSS THE HIGH PLAINS TUESDAY
INTO WEDNESDAY. WITH STRONG CVA AND HEIGHT FALLS ASSOCIATED WITH
THIS SYSTEM EXPECT THE BOUNDARY TO BE PULLED NORTH INTO MN AND WI
AS A WARM FRONT ON TUESDAY. H7 TEMPS OF 13 TO 14 WILL OVERSPREAD
THE AREA AND EFFECTIVELY CAP THE AREA. THE HEAT DOME WILL LIKELY
LEAD TO TEMPS IN THE 90S ACROSS THE AREA. NORTHERN ZONES MAY SEE
SOME SHOWERS AND THUNDER DURING THE DAY...BUT MY CONFIDENCE IS
RATHER LOW IN THIS OCCURRING.

A COLD FRONT ASSOCIATED WITH THIS TROF WILL USHER IN SHOWERS AND
THUNDERSTORMS OVERNIGHT TUESDAY INTO WEDNESDAY MORNING. WITH PWATS
CLOSE TO 2 INCHES IF NOT HIGHER...HEAVY RAIN COULD BE POSSIBLE
FROM THESE SHOWERS AND THUNDERSTORMS TUESDAY NIGHT INTO
WEDNESDAY. AT THIS TIME IT APPEARS AS THOUGH THE THREAT FOR SEVERE
WEATHER WILL BE LOW AS DEEP LAYER SHEAR IS LACKING. CAPE WILL BE
DECREASING AFTER SUNSET SO OVERALL INTENSITY AND HEAVY RAIN
INTENSITY SHOULD BE ON THE DOWN SWING AS WELL.

THE FLOW SHOULD TURN TO WNW THEN AND USHER IN COOLER AND DRIER AIR
INTO THE AREA. TEMPERATURES SHOULD RETURN TO THE LOWER 80S AND
LOWS IN THE 60S. THE REST OF THE WORK WEEK SHOULD BE DRY. AT THE
END OF THE PERIOD THERE IS A CHANCE FOR SHOWERS AND THUNDERSTORMS
AGAIN.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1251 PM CDT SUN JUL 26 2015

WELL DEFINED OUTFLOW BOUNDARY NEAR CID TO MLI TO SAG SOUTH THROUGH
EARLY AFTERNOON BEFORE STALLING NEAR BRL. BEHIND THE OUTFLOW
BOUNDARY WILL BE CHARACTERIZED BY CU WITH IFR TO MVFR CIGS
IMPROVING TO VFR BY LATE AFTERNOON WITH NE/E WINDS AROUND 10 KTS
AND GUSTING OCCASIONALLY TO NEAR 20 KTS. BRL WILL SEE CU WITH
PERIODS OF IFR TO MVFR CIGS WITH MOISTURE POOLING AHEAD OF
BOUNDARY WITH ANY CIGS LIFTING TO VFR BY LATE AFTERNOON. THERE
WILL BE A CHANCE OF A SHOWER OR STORM THIS AFTERNOON AT ALL THE
TAF SITES...BUT CONFIDENCE ON OCCURRENCE AT TERMINAL IS TOO LOW
FOR MENTION BUT WILL MONITOR RADAR AND AMEND IF NEEDED.
OUTFLOW BOUNDARY OR EFFECTIVE WARM FRONT DUE TO DIFFERENTIAL
HEATING WILL SLOWLY LIFT BACK NORTH TONIGHT THROUGH MONDAY.
WITH MOISTURE POOLING IN VICINITY OF BOUNDARY ALONG WITH EAST TO
SOUTHEAST FLOW SHOULD FAVOR LOW CLOUD AND FOG DEVELOPMENT WITH
MVFR TO IFR CONDITIONS LATE TONIGHT INTO MONDAY MORNING...WITH
CHANCE FOR LIFR/VLIFR CONDITIONS. CHANCE FOR A SHOWER OR STORM
WILL EXIST UNTIL THE FRONT PASSES LATER MONDAY... BUT AGAIN TOO
LOW CONFIDENCE FOR MENTION.


&&

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

$$

SYNOPSIS...05
SHORT TERM...GIBBS
LONG TERM...GIBBS
AVIATION...05



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