Area Forecast Discussion
Issued by NWS Quad Cities, IA IL

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000
FXUS63 KDVN 020832
AFDDVN

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
332 AM CDT SAT AUG 2 2014

.SYNOPSIS...
ISSUED AT 330 AM CDT SAT AUG 2 2014

LATEST SFC ANALYSIS WAS INDICATING A BROAD BUT WEAK PRESSURE
PERTURBATION FIELD OF HIGHS AND LOWS ACRS THE UPPER MIDWEST AND INTO
THE WESTERN GRT LKS. LIGHT TO CALM WIND FIELDS AND COOLING TEMPS
PRODUCING SOME PATCHY TO AREAS OF FOG THROUGH THIS SUNRISE.
ALOFT...LONG WAVE TROF AXIS FROM ACRS THE WESTERN GRT LKS DOWN INTO
THE LOWER MS RVR VALLEY AND GULF STATES...WITH A VORT SEEN ON CURRENT
WATER VAPOR LOOP ON IT/S NORTHWEST FLOW WEST SIDE ACRS THE EASTERN
DAKOTAS.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 330 AM CDT SAT AUG 2 2014

TODAY...ANOTHER DAY OF RATHER LIGHT AND VARIABLE WIND REGIME...AND
WARMING TEMPS TO AT LEAST YESTERDAY/S VALUES IF NOT A DEGREE OR TWO
WARMER IN MODERATING DEEP MIXING THERMAL PROFILES. MOST MODELS
SUGGEST BOTH SFC AND A BULGE OF UPPER RIDGING SHIFTING ACRS THE
AREA THIS AFTERNOON AND EVENING WHILE THE DAKOTA VORT DROPS INTO
WESTERN IA BY THIS EVENING. THIS WOULD GENERALLY SUGGEST A MAINLY
DRY DAY...BUT WILL KEEP SLIGHT POPS/ISOLATED SHOWERS AND STORMS IN
THE NORTHEASTERN THIRD TO HALF OF THE DVN CWA MID TO LATE AFTERNOON
DO TO BUOYANCY /CONVECTIVE TEMPS OF 82-84 DEGREES/. WIDESPREAD
HIGHS OF 80 TO 85 WITH MORE AREAS LEANING TOWARD THE MID 80S AND SFC
DPTS AROUND 60.

TONIGHT...WILL KEEP DRY FCST GOING...BUT SUPPOSE AN ISOLATED SHOWER/
STORM POSSIBLE IN THE NORTHERN HALF OF THE CWA FROM 00Z-02Z OR SO.
THE VORT DROPPING DOWN TOWARD WESTERN IA MAY PRODUCE SHOWER/STORM
CLUSTERS ACRS PORTIONS OF WESTERN INTO CENTRAL IA OVERNIGHT...BUT
SHOULD REMAIN WEST OF THE DVN CWA. JUST SOME HIGHER DEBRIS CLOUDS OFF
THIS ACTIVITY POSSIBLY STREAMING INTO THE WESTERN CWA BY LATE
TONIGHT. A CHANCE FOR SOME FOG LATE TONIGHT AS WELL UNDER ONGOING
RIDGING...BUT WONDER IF MIXING OF THE DAY AND THUS DRIER SFC LAYER
CONDITIONS MAY LIMIT IT ENOUGH THAT COVERAGE TOO UNCERTAIN TO MENTION
AT THIS TIME.     ..12..


.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 330 AM CDT SAT AUG 2 2014

MORE TYPICAL SUMMER WEATHER IS IN STORE DURING THIS TIMEFRAME WITH
WARM TEMPS...SEASONAL DEW POINTS AND A CHANCE OF STORMS EACH
DAY...IN AT LEAST PART OF THE CWA.  BEST RAIN CHANCES CONTINUE TO
REVOLVE AROUND WEDNESDAY-THURSDAY.

DIRTY NORTHWEST FLOW ALOFT AND MODEL VARIATION IS MAKING IT
DIFFICULT TO PIN DOWN SHORT WAVE TROUGHS THAT MIGHT SUPPORT
THUNDERSTORM ACTIVITY SUNDAY THROUGH TUESDAY.  AT ANY RATE...THE
MAIN ACTION ZONE LOOKS TO REMAINS GENERALLY TO OUR NORTH SO WILL
ONLY HAVE SLIGHT CHANCE TO LOW CHANCE POPS. I EXPECT STORMS SIMILAR
TO WHAT WE HAD FRIDAY...SLOW MOVING...POP AND DROP PULSE TYPE EVENTS
WITH WEAK FLOW ALOFT.

BY WEDNESDAY THE UPPER LEVEL RIDGE OUT WEST IS BEATEN DOWN BY THE
TROUGH CURRENTLY SITTING INLAND ALONG THE WEST COAST. THE GULF OPENS
UP ALLOWING PW VALUES TO INCREASE.  AND BOTH THE GFS AND ECMWF BRING
FORCING IN THE FORM OF WAA WEDNESDAY AND AN UPPER LEVEL TROUGH AND
SURFACE-850 MB LOW THURSDAY...THOUGH DIFFERENCES IN THE DETAILS
BETWEEN THE TWO WERE NOTED.  THUS HIGHER CHANCE POPS LOOK
APPROPRIATE FOR THIS PERIOD TIME WITH LOCALLY HEAVY RAIN THE MAIN
THREAT. FLOW ALOFT LOOKS A LITTLE WEAK FOR ORGANIZED SEVERE STORMS.

FRIDAY...BOTH MODELS SHIFT THIS SYSTEM TO THE EAST THOUGH A BOUNDARY
AND A WARM AND MOIST AIR MASS REMAIN IN PLACE NEAR THE AREA.  SO LOW
POPS LOOK GOOD HERE.     WOLF

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1139 PM CDT FRI AUG 1 2014

VERY LIGHT WINDS AND MOSTLY CLEAR SKIES WILL BE THE RULE THROUGH
THE REST OF THE NIGHT AS A BROAD AREA OF HIGH PRESSURE REMAINS
OVER THE REGION. GROUND FOG IS EXPECTED TO DEVELOP AND DEEPEN
TOWARD MORNING...REDUCING VISIBILITIES TO 3 TO 6 MILE RANGE AT
ALL SITES UNTIL SUNRISE. SATURDAY WILL REMAIN VFR WITH VERY LIGHT
WINDS. THERE WILL BE A POTENTIAL FOR AT LEAST ISOLATED LATE
AFTERNOON THUNDERSTORMS...WHICH AT THIS TIME ARE EXPECTED TO BE OF
TOO LIMITED IN COVERAGE TO MENTION IN THE TERMINAL FORECASTS.

&&

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

$$

SYNOPSIS...12
SHORT TERM...12
LONG TERM...WOLF
AVIATION...SHEETS





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