Area Forecast Discussion
Issued by NWS Quad Cities, IA IL

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
000
FXUS63 KDVN 270445
AFDDVN

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
1145 PM CDT SUN JUL 26 2015

.UPDATE...
ISSUED AT 817 PM CDT SUN JUL 26 2015

STRONG CAP AROUND 500 MB EVIDENT ON THE DVN 00Z SOUNDING AND
THE LACK OF CLOUD COVER OTHER THAN WEAKENING CU OVER THE REGION
ARE SUGGESTIVE OF LITTLE CONVECTIVE POTENTIAL IN THE IMMEDIATE
SHORT TERM. RADAR STILL SHOW LINGERING LOW LEVEL BOUNDARIES IN
THE WEAK SURFACE WIND FIELDS. SURFACE DEWPOINTS WERE IN THE LOWER
TO MID 70S...CREATING A VERY MUGGY EVENING...WITH THE EXCEPTION OF
THE DBQ ARE INTO NW IL...WHERE SLIGHTLY DRIER AIR FROM THE E-NE
WAS HOLDING DEWPOINTS IN THE UPPER 60S.

HAVE REMOVED SLIGHT CHANCE POPS FOR MOST OF THE NIGHT WITH THE
MOST LIKELY TRIGGER FOR ANY THUNDERSTORMS ARRIVING WITH THE NEXT
UPPER LEVEL RIDGE TOPPING SHORTWAVE TRIGGERING SEVERE STORMS AND
MCS ACTIVITY IN THE PLAINS...WHICH WILL NOT LIKELY ARRIVE UNTIL
CLOSE TO SUNRISE. THE HIGH MOISTURE LEVELS...MAINLY CLEAR
SKIES...AND LIGHT WINDS WILL LIKELY LEAD TO FOG. THIS HAS BEEN
INTRODUCED INTO THE FORECAST AS PATCHY FOR NOW...AS HIGH CLOUDS
ADVANCING FROM THE PLAINS CONVECTION MAY LIMIT THE EXTENT...BUT
WILL NEED TO WATCH TRENDS CLOSELY.

&&

.SYNOPSIS...
ISSUED AT 339 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 339 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 339 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 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1144 PM CDT SUN JUL 26 2015

LIGHT WINDS AND LINGERING LOW LEVEL MOISTURE WILL LIKELY LEAD TO
WIDESPREAD MVFR FOG LATE TONIGHT INTO EARLY MONDAY MORNING. WITH A
WEAK EASTERLY FLOW THIS EVENING...SLIGHTLY DRIER LOW LEVEL AIR IS
SPREADING INTO THE AREA...WHICH HAS LOWERED THE POTENTIAL FOR
THICK FOG AND THE LATEST FORECASTS HAVE SLIGHTLY HIGHER
VISIBILITIES AND NO LONGER DEPICT LOW CLOUD DEVELOPMENT. THE
POTENTIAL FOR THUNDERSTORMS IS NEARLY NILL OVERNIGHT...FOLLOWED BY
A LOW POTENTIAL FOR AT LEAST ISOLATED THUNDERSTORMS DURING THE DAY
MONDAY...WHICH ARE NOT INCLUDED IN THE FORECASTS. CONDITIONS
SHOULD IMPROVE TO VFR AT ALL SITES BY MID MORNING AND REMAIN
UNLIMITED THROUGH THE DAY WITH LIGHT EAST TO SOUTHEAST WINDS AT
ALL SITES.

&&

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

$$

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


USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.