Area Forecast Discussion
Issued by NWS Quad Cities, IA IL

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000
FXUS63 KDVN 301154
AFDDVN

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
654 AM CDT SAT AUG 30 2014

.SYNOPSIS...
ISSUED AT 349 AM CDT SAT AUG 30 2014

LATEST SFC ANALYSIS WAS INDICATING MAIN LOW OVER THE MN/WI/IA TRI-
STATE REGION FOLLOWING PRESSURE FALLS MAX TOWARD NORTHEASTERN WI.
ALOFT...WATER VAPOR IMAGERY AND 00Z UPPER AIR ANALYSIS WAS
INDICATING MAIN VORT MAX ACRS CENTRAL INTO NORTHEASTERN IA...WITH A
SECONDARY LOBE ACRS THE EASTERN DAKOTAS INTO CENTRAL NEB. SCTRD
SHOWERS AND SOME THUNDERSTORMS ASSOCIATED WITH THE NEARBY VORT
MAX CURRENTLY PROGRESSING NORTHEASTWARD ACRS THE LOCAL FCST AREA.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 349 AM CDT SAT AUG 30 2014

TODAY...AS THE VORT MAX AND UPPER TROF CONTINUES TO MIGRATE
NORTHEASTWARD ACRS WI...EXPECT LINGERING SCTRD TO ISOLATED SHOWERS
AND A FEW STORMS TO CONTINUE TO MOVE ACRS THE CWA THROUGH MID
MORNING. MORE PRECIP COVERAGE EAST OF THE MS RVR AND SOME WRAP AROUND
EFFECT SOUTH OF PASSING VORT MAX ACRS THE NORTHERN CWA. BRUNT OF
FORCING OFF SECONDARY VORT WILL LOOK TO PASS NORTH OF THE AREA
INTO THIS AFTERNOON...BUT LOBE OFF THIS FEATURE TO STILL POSSIBLY
KICK UP AN ISOLATED SHOWER OR STORM MIDDAY THROUGH MID AFTERNOON
OVER MAINLY THE NORTH HALF OF THE CWA. HOTTER PRECIP FIRING ZONE
THIS AFTERNOON WILL LOOK TO SET UP JUST TO THE SOUTHEAST OF THE
CWA ALONG LLVL CONVERGENT FIELD ALONG SFC TROF OR FRONTAL TYPE
FEATURE ACRS CENTRAL MO AND CENTRAL IL INTO NORTHWESTERN INDIANA. A
LOW CHC FOR SOME OF THIS TO TAKE OFF IN THE FAR SOUTHEASTERN CWA
NEAR MACOMB. OTHERWISE CLOUD COVER ASSOCIATED WITH THE WAVE TO
PERSIST THROUGH LATE MORNING OR MIDDAY...BEFORE SOME PARTIAL
CLEARING TO OCCUR FOR THE AFTERNOON. THIS WILL ALLOW FOR TEMPS TO
WARM INTO THE UPPER 70S TO LOWER 80S ACRS MOST OF THE AREA WITH
MIXING WEST TO SOUTHWEST SFC WINDS OF 10 TO 15 MPH. IF CLOUDS ARE
STUBBORN AND HOLD ON LONGER...MORE AREAS HELD IN THE 70S. AND IF
POST-VORT SUBSIDENCE BUILDS IN FOR A QUICKER CLEAR OUT THAN
CURRENTLY EXPECTED...SOME AREAS TO POTENTIALLY WARM INTO THE MID 80S.

TONIGHT...MOST OF THE VARIOUS 00Z RUN MODEL GUIDANCE IN DECENT
AGREEMENT OF SUGGESTING UPSTREAM SFC AND UPPER RIDGING TO BUILD ACRS
THE REGION FOR CLEARING SKIES AND DECOUPLING SFC WINDS. WITH
AMBIENT TEMPS COOLING TOWARD MID 60 SFC DPTS AND LONGER NIGHT
PERIOD...IT APPEARS TO BE A SET UP TONIGHT FOR SOME FOG FORMATION
ESPECIALLY AFTER MIDNIGHT. SOME POTENTIAL FOR AREAS OF DENSE
FOG. FOR NOW WITH SOME UNCERTAINTY OF FOG EXTENT AND COVERAGE...WILL
INTRODUCE PATCHY FOG WORDING LATER TONIGHT AND ALLOW FOR DAY CREW TO
FURTHER ASSESS IF NEED TO BEEF UP WORDING. SOME LOWS POSSIBLY DIPPING
INTO THE LOWER 60S IN THE NORTHWEST IF SKIES REMAIN CLEAR. A FEW
MODELS SUGGESTING AN ELEVATED WAR AIR ADVECTION WING INDUCED BY
SOUTHWESTERLY 30-40 KT H85 MB JET CONVERGING INTO SLOWER FLOW ACRS
SOUTHERN MN INTO NORTH CENTRAL IA LATE TONIGHT BUT MOST MODELS NOT
BREAKING OUT ANY PRECIP WITH THIS PROCESS FOR NOW. MAY JUST BE SOME
AC THAT MAY GET INTO THE NORTHWESTERN OR NORTHERN CWA...BUT THAT
WOULD EFFECT LOW TEMP POTENTIAL AS WELL AS FOG FORMATION.   ..12..

.LONG TERM...(SUNDAY THROUGH NEXT FRIDAY)
ISSUED AT 349 AM CDT SAT AUG 30 2014

SUNDAY... GOOD MID LEVEL THETA-E ADVECTION PROGGED BY SOME MODELS
BRUSHING PORTIONS OF NORTHEAST IA DURING THE AM... BUT WITH UPPER
RIDGE AND BUILDING HEIGHTS HAVE KEPT POPS BELOW MENTION ATTM. LATE
IN THE DAY THE UPPER RIDGE MOVES EAST AND BEGIN TO SEE
INCREASINGLY DIFFLUENT FLOW AHEAD OF SHORTWAVE TROUGH MOVING INTO
THE NORTHERN PLAINS. CAN/T RULE OUT ISOLD CONVECTION LATE
AFTERNOON ONCE AGAIN OVER PORTIONS OF NORTHEAST IA... BUT HELD OFF
MENTION UNTIL AFTER 00Z. DESPITE SOUTHEAST WINDS HIGHS ON SUNDAY
SHOULD BE WARMER THAN THOSE OF SATURDAY AND MAINLY IN THE RANGE OF
83-88F WITH AMPLE SUNSHINE.

SUNDAY NIGHT... CONTINUED INCREASINGLY DIFFLUENT FLOW ALOFT WITH
SHORTWAVE TROUGH MOVING INTO THE UPPER MIDWEST AND PSEUDO WARM FRONT
LIFTING NORTHWARD INTO REGION TO COMBINE FOR SHOWERS AND STORMS
WITH GREATEST COVERAGE ATTM SUGGESTED WITH TRIPLE POINT WEST OF THE
MISSISSIPPI RIVER AND NORTH OF I-80. TIMING TOWARD DIURNAL MINIMUM
LATER EVENING INTO OVERNIGHT LENDING TO LIMITED SEVERE POTENTIAL
WITH CONVECTION PAST MATURE INTO GRADUAL WEAKENING STAGES. LOWS IN
THE RANGE OF THE UPPER 60S TO LOWER 70S ANTICIPATED WITH SOUTHERLY
WINDS AHEAD OF COLD FRONT.

MONDAY-MONDAY NIGHT... SHOWERS AND STORMS WEAKENING WHILE MOVING
ACROSS THE AREA DURING THE AM. POTENTIAL FOR AT LEAST SCATTERED
RE-DEVELOPMENT OF STORMS MONDAY AFTERNOON MAINLY SOUTHEAST 1/3-1/2
OF CWA AHEAD OF FRONT AND WITH ADDITIONAL LIFT FROM RIGHT ENTRANCE
REGION OF UPPER JET. ANY SEVERE RISK WILL BE LARGELY DEPENDENT ON
DEGREE OF HEATING/DESTABILIZATION GIVEN FAVORABLE DEEP LAYER SHEAR
0-6KM AROUND AT LEAST 40 KTS PER NAM AND GFS. SHOWERS AND STORMS
MONDAY NIGHT SHOULD GRADUALLY MIGRATE SOUTHEAST OF CWA WITH FRONT.
COOLER LOWS NORTHEAST IA IN THE UPPER 50S TO AROUND 60 WHILE WARMEST
FAR SOUTHEAST IN THE MID 60S.

TUESDAY-FRIDAY... CONTINUED MEDIUM RANGE MODEL RUN TO RUN VARIANCES
WITH LOCATION OF FRONTAL ZONE IN QUASI-ZONAL FLOW MAKING FOR LOWER
CONFIDENCE FORECAST. ADDITIONAL ENERGY DIGGING DOWN BACKSIDE OF
DEPARTING TROUGH MAY KEEP SOME CHANCE OF SHOWERS AND STORMS ON TUE.
WHILE MODELS CONTINUE TO STRUGGLE WITH FRONT LOCATION... BASED ON THE
SUBTROPICAL RIDGE TO OUR SOUTH I FAVOR THE BOUNDARY TO OUR SOUTH FOR
A DRIER SCENARIO MIDWEEK. FRONT THEN SHOULD EVENTUALLY LIFT BACK NORTH
LATE WEEK INTO NEXT WEEKEND WITH DEVELOPING SOUTHWESTERLY FLOW ALOFT
FOR RETURN TO ACTIVE/UNSETTLED WEATHER WITH TEMPS NEAR TO ABOVE
NORMAL.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 643 AM CDT SAT AUG 30 2014

WITH LOW PRESSURE MOVING OFF TO THE NORTHEAST ACRS WI THIS MORNING...
VARIABLE WRAP AROUND CONDITIONS WITH VARYING BOUTS OF MVFR TO IFR
CIGS ACRS THE TERMINALS. LINGERING SHOWERS MAINLY NORTH OF HWY 30
THROUGH MID MORNING. MORE WIDESPREAD SUB 1000 FT CIGS OUT ACRS THE
WEST HALF OF IA MAY MOVE INTO THE TERMINALS BY MID MORNING...BUT
SOME POTENTIAL OF THEM DIURNALLY LIFTING TO AROUND 1K FT OR
HIGHER BY THEN. THE CIGS WILL LIFT TO HIGHER MVFR OR EVEN VFR AND
SCATTER OUT FROM EARLY TO MID AFTERNOON. WEST TO SOUTHWEST SFC
WINDS OF 8 TO 14 KTS TODAY...BEFORE BECOMING LIGHT AND VARIABLE
THIS EVENING AS HIGH PRESSURE SETTLES ACRS THE REGION. WITH
CLEARING SKIES AND LIGHT WINDS TONIGHT...THERE WILL BE THE CHC FOR
FOG DEVELOPMENT SOME POTENTIALLY DENSE/IFR OR LIFR AT MOST TAF SITES.
THE FOG WILL BE MORE WIDESPREAD AFTER MIDNIGHT AND INTO EARLY
SUNDAY MORNING.     ..12..

&&

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

$$

SYNOPSIS...12
SHORT TERM...12
LONG TERM...05
AVIATION...12






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