Area Forecast Discussion
Issued by NWS Quad Cities, IA IL

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000
FXUS63 KDVN 170854
AFDDVN

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
354 AM CDT FRI APR 17 2015

.SYNOPSIS...
ISSUED AT 330 AM CDT FRI APR 17 2015

HIGH PRESSURE OVER THE CWA WAS PROVIDING LIGHT TO CALM WINDS AND
GENERALLY PARTLY CLOUDY SKIES. 3 AM TEMPERATURES RANGED FROM 47 AT
MOLINE TO 61 AT VINTON.

ELSEWHERE...00Z/17 SUBJECTIVE UPPER AIR ANALYSIS INDICATED A SPLIT FLOW
ACROSS THE CONUS WITH A CUT-OFF CLOSED LOW SPINNING NEAR THE 4-CORNERS
REGION. THIS WAS PRODUCING SHOWERS AND THUNDERSTORMS FROM KS INTO THE
TX PANHANDLE. ISOLATED STORMS WERE ALSO SOUTH OF BEATRICE NE WHERE WEAK
WARM AIR ADVECTION/850 MB MOISTURE TRANSPORT WAS UNDERWAY.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 330 AM CDT FRI APR 17 2015

FORECAST FOCUS ON A WARM DAY THEN A SMALL CHANCE FOR THUNDERSTORMS TONIGHT.

TODAY...HIGH PRESSURE WILL GRADUALLY SHIFT TO THE EAST BUT THERE WILL
BE PLENTY OF SUNSHINE ALONG WITH A LIGHT SOUTH WIND. THIS SHOULD PUSH
AFTERNOON TEMPERATURES INTO THE MID TO UPPER 70S AT MOST LOCATIONS...USING
THE PARCEL TRAJECTORY METHOD.

TONIGHT...OPERATIONAL MODELS INDICATE WEAK WARM AIR ADVECTION DEVELOPING
LATER THIS EVENING AND OVERNIGHT...ESPECIALLY IN OUR FAR WESTERN COUNTIES.
TIME HEIGHT SECTIONS SUGGEST ENOUGH MID LEVEL FORCING AND INSTABILITY
TO TRIGGER ISOLATED ELEVATED THUNDERSTORMS. I WILL MAINTAIN THE SMALL
POPS IN OUR FAR WESTERN COUNTIES BUT THE REMAINDER OF THE CWA SHOULD
REMAIN DRY...CLOSER TO HIGH PRESSURE RIDGE IN THE GREAT LAKES REGION.
MID LEVEL CLOUDS WILL BE THICKENING DURING THE EVENING AND OVERNIGHT
HOURS WHICH WILL ENSURE ANOTHER MILD NIGHT...WITH LOWS IN THE 50S.
BY 12Z SATURDAY OPERATIONAL MODELS NUDGE THE CLOSED UPPER LOW INTO
EASTERN CO.

.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 330 AM CDT FRI APR 17 2015

INCREASING RAIN CHANCES THIS WEEKEND...THEN TURNING COOLER AND MAINLY
DRY EARLY-MID NEXT WEEK.

MODELS IN FAIRLY GOOD AGREEMENT THAT THE CLOSED UPPER LOW OVER THE
FOUR CORNERS REGION WILL DEAMPLIFY INTO AN OPEN WAVE WHILE
LIFTING TOWARD THE MID-MISSISSIPPI VALLEY OVER THE WEEKEND. A FEW
ELEVATED SHOWERS AND PERHAPS AN ISOLD STORM WILL BE POSSIBLE ON
SATURDAY WITH WEAK MID LEVEL WARM ADVECTION AND CONVERGENCE. BEST
CHANCES FOR SHOWERS AND SOME STORMS WILL GRADUALLY ENVELOP THE
CWA SATURDAY NIGHT THROUGH SUNDAY AS MOIST CONVEYOR (NAEFS MEAN
PRECIPITABLE WATER VALUES OF 1-1.25+ INCHES) LIFTS OVER REGION IN
ADVANCE OF UPPER LEVEL SHORTWAVE. TRENDS AND JUXTAPOSITION OF
FORCING AND MOISTURE FAVOR HEAVIEST RAINFALL TO OUR SOUTH/EAST BUT
STILL SUGGEST POTENTIAL FOR FAIRLY WIDESPREAD MODERATE AMOUNTS OF
0.25 TO 0.75 INCH SATURDAY NIGHT THROUGH SUNDAY. SEVERE RISK WITH
ANY STORMS APPEARS LOW DUE TO LIMITED INSTABILITY AND SHEAR. PRIOR
TO ARRIVAL OF RAIN SHOULD SQUEAK OUT ENOUGH SOLAR INSOLATION FOR
ONE MORE DAY OF ABOVE NORMAL TEMPS ON SATURDAY... WITH WIDESPREAD
HIGHS IN THE 70S. COOLER ON SUNDAY WITH HIGHS MAINLY IN THE 60S DUE
TO CLOUDS AND PCPN.

EARLY TO MID NEXT WEEK... REASONABLE AGREEMENT FROM MODELS ON REMNANT
OPEN WAVE LIFTING THROUGH MID-MISSISSIPPI VALLEY PHASING WITH
SOUTHERN CANADA SHORTWAVE TO FORM SLOW MOVING CLOSED LOW OVER WESTERN
GREAT LAKES. THIS WILL THRUST CWA IN NORTHWEST FLOW RESULTING IN TEMPS
NEAR TO BELOW NORMAL (HIGHS 50S/60S). IN ADDITION...COULD SEE SOME
SHOWERY PCPN SKIRT MAINLY THE NORTHERN CWA MONDAY POSSIBLY INTO
TUESDAY. THEN... TOWARD THE END OF THE PERIOD /LATE WEDNESDAY AND
JUST BEYOND/ THERE MAY BE A CHANCE OF SOME PCPN FOCUSING NEAR THE
SOUTHERN CWA WITH DEVELOPING PLAINS TO MID-MISSISSIPPI VALLEY
FRONTAL ZONE AND INCREASING RETURN FLOW. LOW CONFIDENCE FORECAST
AS MODEL VARIABILITY HIGH WITH GENERAL TRENDS SEEMING TO SUPPORT
MUCH IF NOT ALL OF PCPN FOCUSING OVER PORTIONS OF THE CENTRAL/SOUTHERN
PLAINS INTO LOWER MISSISSIPPI VALLEY... WHICH IS IN LINE WITH PATTERN
OF LATE.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 330 AM CDT FRI APR 17 2015

VFR CONDS THROUGH THIS TAF CYCLE. ISOLATED THUNDERSTORMS POSSIBLE
LATER THIS EVENING IN PORTIONS OF EASTERN IOWA. SOUTH WINDS 5 TO
10 KNOTS TODAY THEN SOUTHEAST AROUND 5 KNOTS TONIGHT.

&&

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

$$

SYNOPSIS...HAASE
SHORT TERM...HAASE
LONG TERM...05
AVIATION...HAASE





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