Area Forecast Discussion
Issued by NWS Quad Cities, IA IL

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000
FXUS63 KDVN 050358
AFDDVN

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
1058 PM CDT TUE AUG 4 2015

.SYNOPSIS...
ISSUED AT 329 PM CDT TUE AUG 4 2015

LATEST SFC ANALYSIS WAS INDICATING RIDGE HANGING ON ACRS THE UPPER
MS RVR VALLEY INTO THE GRT LKS...WHILE A QUASI-STATIONARY BOUNDARY
UNDULATED ACRS NORTHERN KS INTO CENTRAL MO/SOUTHERN IL. ALOFT...A
WAVE COMPLEX PUSHING INTO THE WEST CENTRAL TO NORTHWESTERN HIGH
PLAINS WAS TRYING TO UNDERCUT MID CONUS OMEGA RIDGE. CYCLONIC UPPER
FLOW CONTINUED ACRS THE UPPER MS RVR VALLEY INTO THE GRT LKS WITH A
FEW WEAK VORTS EMBEDDED IN THIS FLOW AS WELL.

&&

.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 329 PM CDT TUE AUG 4 2015

TONIGHT...BULK OF 12Z RUN MODELS SEEM TO TAKE INTO ACCOUNT THE
STRENGTH OF UPPER RIDGE AND IT/S LEE SIDE CYCLONIC FLOW TO THE EAST
OF THE WEST PLAINS UPPER WAVE COMPLEX...THUS EFFECTIVELY SHUNTING IT
EAST-SOUTHEASTWARD TOWARD NORTHWEST MO BY WED MORNING. WHILE MORE
CONVECTIVELY ACTIVE ZONE CONTINUES TO TAKE OFF ALONG AND JUST NORTH
OF THE BOUNDARY ACRS KS/SOUTHERN NEB AND CENTRAL MO...COULD SEE THE
LOCAL CWA STAY MOSTLY DRY THIS EVENING WITH JUST DEBRIS CLOUDS
STREAMING ACRS THE AREA. WILL STILL MAINTAIN LOW CHC POPS ACRS THE
FAR SOUTHWEST FOR ELEVATED SHOWERS...WITH A POSSIBLE UPTICK IN
ACTIVITY TOWARD MIDNIGHT AS SECONDARY SOUTHWESTERLY LLJ CONVERGENT
RIBBON IMPINGES ON THE SOUTHWESTERN CWA...BETTER LLJ FORCING WEST
AND SOUTHWEST OF THE CWA THOUGH AT THIS TIME. WILL MAKE LITTLE
CHANGE TO ONGOING LOW TEMPS WITH MID 50S POSSIBLE IN THE FAR NORTH
AN NORTHEAST UNDER THINNER CLOUD COVER AND LOWER SFC DPT POOL...TO
THE MID 60S IN THE SOUTHWEST IN HIGHER DPTS AND MORE CLOUD COVER
EXPECTED.

WEDNESDAY...THE UPPER WAVE WILL LOOK TO CONTINUE TO ROLL ACRS MO AN
MAKE FOR ALMOST A MINI REX-TYPE BLOCK PATTERN ACRS THE MID WEST.
BOTH UPPER AND LOWER RIDGING MAY HAVE MORE OF AN INFLUENCE ON THE
LOCAL CWA THAN THE MO VORT MAX WITH MUCH OF THE AREA ESPECIALLY THE
NORTHERN HALF TO TWO THIRDS STAYING MAINLY DRY ON WED WITH CONTINUED
HIGHER BASED DEBRIS CLOUDS FILTERING THE SUNSHINE. WILL ADJUST POPS
ACCORDINGLY...AND FOLLOWING SHIFTS MAY BE ABLE TO TRIM FURTHER BACK
TO THE SOUTH IF 00Z MODELS AND UPSTREAM WAVE TRENDS CONTINUE WITH
THE CURRENT TRENDS. HIGHS AGAIN IN THE UPPER 70S TO LOWER 80S
ALTHOUGH THICKER CLOUD COVER THAN CURRENTLY ANTICIPATED MAY MAKE FOR
MORE UPPER 70S THAN 80S.   ..12..

.LONG TERM...(WEDNESDAY NIGHT THROUGH NEXT TUESDAY)
ISSUED AT 329 PM CDT TUE AUG 4 2015

AN UPPER LEVEL DISTURBANCE WILL PASS JUST SOUTH OF THE AREA
WEDNESDAY NIGHT. SINCE THE BETTER MOISTURE IS SOUTH OF THE AREA ONLY
ISOLATED TO SCATTERED CONVECTION IS EXPECTED SOUTH OF I-80.

DRY CONDITIONS WILL BE SEEN ACROSS THE AREA THURSDAY AND THURSDAY
EVENING AS HIGH PRESSURE MOVES INTO THE EASTERN LAKES. TEMPERATURES
ON THURSDAY SHOULD BE CLOSE TO NORMAL.

LATE THURSDAY NIGHT AND FRIDAY A WEAK FRONT WILL MOVE THROUGH THE
AREA. THE BETTER FORCING IS NORTH OF THE AREA BUT THE OVERALL
CONVERGENCE ALONG THE FRONT MAY BE ENOUGH TO GENERATE ISOLATED TO
SCATTERED CONVECTION.

FRIDAY NIGHT ON...

THE MODEL CONSENSUS BRINGS ANOTHER WEAK FRONT THROUGH THE AREA
FRIDAY NIGHT. THE BETTER MOISTURE/FORCING ARE IN THE PLAINS AND
LOWER MISSISSIPPI VALLEY SUGGESTING DRY CONDITIONS. THE MODEL
CONSENSUS DOES HAVE SLIGHT CHANCE POPS ASSOCIATED WITH THE FRONT IN
THE FAR EAST AND NORTHEAST AREAS.

ON SATURDAY THE MODEL CONSENSUS HAS NEAR NORMAL TEMPERATURES AND
SLIGHT CHANCE POPS. ANY FORCING THAT IS PRESENT IS QUITE WEAK SO
THIS COULD BE THE MODELS DEVELOPING NORMAL AFTERNOON DIURNAL
CONVECTION.

SATURDAY NIGHT/SUNDAY...THE MODEL CONSENSUS HAS SLIGHT/CHANCE AND
CHANCE POPS RESPECTIVELY. INTERNALLY...THE MODELS ARE SUGGESTING
ANOTHER ORGANIZED THUNDERSTORM COMPLEX DEVELOPING AND MOVING THROUGH
THE MIDWEST. THE KEY WILL BE WHERE THE COMPLEX DEVELOPS AND MOVES.
SOME MODEL SOLUTIONS KEEP THE COMPLEX NORTH OF THE AREA WHILE AT
LEAST ONE HAS IT SOUTH OF THE AREA. WHEN TAKING CONCEPTUAL MODELS
INTO CONSIDERATION...THEY SUGGEST THE POSSIBILITY OF THE COMPLEX
DEVELOPING AND MOVING ACROSS IOWA INTO ILLINOIS.

SUNDAY NIGHT/MONDAY THE MODEL CONSENSUS HAS CHANCE AND SLIGHT CHANCE
POPS RESPECTIVELY. WHAT OCCURS DURING THIS TIME PERIOD WILL BE VERY
DEPENDENT UPON WHAT OCCURS WITH THE THUNDERSTORM COMPLEX SATURDAY
NIGHT/SUNDAY.

EARLY NEXT WEEK THERE ARE INDICATIONS THAT AN UPPER LOW WILL DEVELOP
OVER THE GREAT LAKES AND KEEP THE AREA IN NORTHWEST FLOW. AS SUCH
THE MODEL CONSENSUS HAS MAINLY DRY CONDITIONS FOR MONDAY NIGHT AND
TUESDAY.    ..08..

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1055 PM CDT TUE AUG 4 2015

VFR CONDS THROUGH THIS TAF CYCLE. WEAK HIGH PRESSURE OVER THE AREA
WILL SLIP INTO THE GREAT LAKES REGION ON WEDNESDAY. MEANWHILE...A
NEARLY STATIONARY EAST-WEST FRONTAL BOUNDARY WILL BE ACROSS CENTRAL
MO. ISOLATED TO SCATTERED SHOWERS EXPECTED ALONG AND SOUTH OF
HIGHWAY 34 THROUGH THE PERIOD. VARIABLE WINDS LESS THAN 5 KNOTS
TONIGHT THEN SOUTHEAST 5 TO 10 KNOTS ON WEDNESDAY AND EAST
WEDNESDAY NIGHT.

&&

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

$$

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


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