Area Forecast Discussion
Issued by NWS Quad Cities, IA IL

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000
FXUS63 KDVN 290851
AFDDVN

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
351 AM CDT FRI AUG 29 2014

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 348 AM CDT FRI AUG 29 2014

TODAY...WILL WALK OUT ONGOING WARM AIR ADVECTION WING OF
SHOWERS/STORMS OUT OF THE NORTHWESTERN/NORTHERN THIRD OF THE DVN CWA
BY MID MORNING...WITH JUST A SLIGHT CHC OR ISOLATED COVERAGE OF
OTHER SHOWERS OR STORMS TO POP UP FURTHER TO THE SOUTH AS THE
MORNING PROGRESSES. MUCH OF THE CWA COULD BE DRY AFTER 12-14Z THIS
MORNING AS THE WING AND ASSOCIATED LEAD VORT LIFTS UP INTO MN AND
WI. THERE IS A SECONDARY LLVL CONVERGENT ZONE ACRS THE NORTHEASTERN
HALF OF IL THIS MORNING THAT COULD KEEP A FEW SHOWERS FESTERING IN
THE FAR EASTERN CWA THROUGH LATE MORNING. ISOLATED COVERAGE OR
MAINLY DRY CONDITIONS TO CONTINUE INTO EARLY TO MID
AFTERNOON...BEFORE MAIN UPPER WAVE/VORT COMPLEX SEEN NOW ON WATER
VAPOR IMAGERY ACRS KS INTO OK LOOKS TO LIFT UP ACRS THE MO RVR
VALLEY AND SOUTHWESTERN IA BY THIS EVENING. ALL SIGNS SUGGEST ANOTHER
ASSOCIATED LEAD WARM AIR ADVECTION WING AHEAD OF THIS FEATURE TO
POSSIBLY PRODUCE A BAND OF SHOWERS/STORMS THAT WILL GATHER STRENGTH
AND PUSH ACRS THE WESTERN HALF OF THE DVN CWA BY LATE AFTERNOON AND
INTO EARLY EVENING. DEPENDING ON EXTENT OF HEATING AND INSTABILITY
BUILD UP WHICH IS A BIG UNCERTAINTY...IF TEMPS COULD AT LEAST REACH
THE MID 80S WITH SFC DPTS IN THE UPPER 60S TO LOWER 70S A FEW STRONG
STORMS MAY OCCUR WITH WIND GUSTS OF 40 TO 50+ MPH AND HALF INCH
HAIL. SFC WARM FRONT RETREAT SPEED AND TIMING AND ADDITIONAL WAA TYPE
CLOUDS TO BE BIG FACTORS...BUT WILL BANK ON THE STRENGTH OF THE
APPROACHING WAVE TO HELP LLVL WARM PUSH UP THROUGH THE CWA AND LLVL
SOUTHERLY FLOW. WITH EXTENT OF MIXING...EVEN PARTLY SUNNY SKIES WILL
ALLOW FOR WIDESPREAD LOW TO MID 80S SOUTH OF THE WARM FRONT. MORE
SUN AND DEEPER MIXING IN THE THERMAL PROFILES ADVECTING UP ACRS THE
AREA SUPPORT HIGHS IN THE UPPER 80S TO AROUND 90. IF TEMPS COULD
APPROACH THESE VALUES...A BETTER CHC FOR ISOLATED SVR STORMS WITH
DAMAGING WIND GUSTS THIS AFTERNOON INTO EARLY EVENING. A STORM
CLUSTER DEVELOPING A SFC COLD POOL AND MIXING INTO A HIGHER CAPE
FIELD. WILL PLAY HIGH TEMPS IN THE MIDDLE OF THE ROAD OF THE
POTENTIAL...AGAIN LEANING TOWARD THE WARM FRONT MAKING HEADWAY
THROUGH MUCH OF THE AREA BY LATE AFTERNOON WITH SOUTH SFC WINDS
LEADING TO MUCH OF THE FCST AREA IN THE LOW TO MID 80S. OF COURSE
ANOTHER DAY WITH BIG BUST POTENTIAL...MORE CLOUDS AND FRONTAL HOLD UP
WILL KEEP TEMPS IN THE 70S ALONG AND NORTH OF THE BOUNDARY...AND MORE
SUN IN THE SOUTH COULD MAKE FOR SOME UPPER 80S OR EVEN A 90.

TONIGHT...AS THE APPROACHING UPPER WAVE PROPAGATES ACRS CENTRAL IA
BY MIDNIGHT...MAIN LIFT WINDOW ACRS EASTERN IA INTO NORTHWESTERN IL
WILL OCCUR FROM 00Z-07Z OR SO AND EXPECT MOST COVERAGE OF A PRECIP
COMPLEX OF SHOWERS AND EMBEDDED THUNDERSTORMS ACRS THE CWA DURING
THAT TIME FRAME. HIGH POPS WARRANTED TONIGHT. SOME WINGS OF STRONGER
THUNDERSTORMS POSSIBLE ON SOUTHERN AND SOUTHEASTERN FLANK OF
CONVECTIVE SYSTEM. WITH PRECIPITAL WATER FEED OF 1.6 TO 1.8 INCHES
THIS EVENING AND DEEP LAYER SHEAR OF 30-35+ KTS...LOCALLY HEAVY
RAIN A GOOD BET WITH SOME LOCATIONS RECEIVING 1 TO 2 INCHES BY THE
TIME THE ACTIVITY STARTS TO MIGRATE EASTWARD OUT OF THE CWA AFTER
09Z SAT MORNING. MOST AREAS FROM 0.45 TO 1 INCH. IN AREAS THAT
GET HIT REPEATEDLY...URBAN AND SMALL STREAM FLOODING LIKELY WITH A
CHANCE AT EVEN LOCALIZED FLASH FLOODING. LOWS TONIGHT IN THE MID
60S IN THE NORTHWEST TO THE UPPER 60S TO AROUND 70 IN THE
SOUTHEAST.    ..12..


.LONG TERM...(SATURDAY THROUGH NEXT THURSDAY)
ISSUED AT 348 AM CDT FRI AUG 29 2014

SHOWERS AND STORMS WILL MOVE THROUGH EARLY ON SATURDAY... BUT WILL
HAVE A CHANCE OF SOME REDEVELOPMENT SATURDAY AFTN WITH SECONDARY
VORT MAX ESPECIALLY NEAR AND EAST OF THE MISSISSIPPI RIVER.
OTHERWISE... HUMID WITH SKIES BECOMING PTSUNNY AND HIGHS GENERALLY
IN THE UPPER 70S AND LOWER 80S.

SAT NGT-SUN... MAINLY DRY PERIOD AS MID/UPPER LEVEL RIDGING BUILDS
IN OVER REGION IN WAKE OF DEPARTING TROUGH. SKIES SHOULD BE
CLEAR TO PTCLDY WITH LOWS SAT NGT IN THE 60S... AND WARMER HIGHS
ON SUNDAY MAINLY IN THE MID 80S WITH CONTINUATION OF HUMID
CONDITIONS.

SUN NGT-MON... THIS PERIOD LOOKS LIKE NEXT BEST CHANCE OF SHOWERS
AND STORMS WITH UPPER LEVEL SHORTWAVE MOVING FROM THE NORTHERN
PLAINS INTO THE UPPER MIDWEST...WITH ATTENDANT SURFACE LOW PASSING
TO OUR NORTH PULLING WARM FRONT NORTHWARD INTO THE REGION. THIS
SHORTWAVE AND WARM FRONT INTERACTION TO ALLOW FOR LIKELIHOOD OF
SHOWERS AND STORMS ACROSS THE AREA. TIMING OF MAINLY LATER SUNDAY
EVE AND OVERNIGHT WITH INITIAL WAVE OF PCPN LENDS A LIMITED SEVERE
POTENTIAL ALTHOUGH A FEW STRONG STORMS WITH GUSTY WINDS AND HAIL
MAY BE POSSIBLE MOSTLY WEST OF THE MISSISSIPPI RIVER. REDEVELOPMENT
OF SHOWERS AND STORMS ANTICIPATED MON AFTN AHEAD OF COLD FRONT
ATTENDANT TO PASSING UPPER MIDWEST SHORTWAVE. ANY SEVERE RISK WILL
BE DEPENDENT ON AMOUNT OF HEATING AND DESTABILIZATION... WHICH IS
A BIT UNCERTAIN THIS FAR OUT.

MON NGT-THU... LOWER CONFIDENCE EXISTS AS MODELS CONTINUE TO SHOW
SOME DISAGREEMENT ON PLACEMENT OF MAIN SYNOPTIC FRONT AND TIMING
OF SHORTWAVES IN ZONAL FLOW ALOFT. GENERAL SUGGESTION OF SUBTROPICAL
RIDGING FROM SOUTHERN PLAINS INTO THE SOUTHEAST WOULD LEND SUPPORT
TO FRONT STALLING OUT SOUTH OF THE CWA... BUT GIVEN POOR MODEL
CONSISTENCY HAVE TO UNFORTUNATELY MAINTAIN SLIGHT CHC POPS FOR MUCH
OF AREA FOR MUCH OF THIS PERIOD FOR NOW AND AWAIT BETTER CLARIFICATION
ON FRONTAL PLACEMENT AND TIMING OF DISTURBANCES. TEMPS OVERALL LOOK
TO BE NEAR SEASONAL NORMS.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1129 PM CDT THU AUG 28 2014

LINGERING IFR AND SOME MVFR CLOUDS MOSTLY AT CID/DBQ FROM TODAY/S
RAINS WILL DISSIPATE OVERNIGHT WITH PARTLY CLOUDY SKIES THROUGH
TOMORROW AFTERNOON. HENCE...VFR CONDITIONS WILL DOMINATE WITH A
CHANCE FOR SHOWERS AND STORMS...MAINLY AFTER 29/18Z AS UPPER
TROUGH PASSES...WITH THE STRONGEST CELLS PRODUCING MVFR CONDITIONS
IN MODERATE TO HEAVY RAIN AND BASES OF 1-3K AGL. THIS IS HANDLED
AS A PROB30 GROUP. SE WINDS OF 5 TO 10 KTS TO CONTINUE THROUGH
LATE FRIDAY.

&&

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

$$

SHORT TERM...12
LONG TERM...05
AVIATION...NICHOLS






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