Area Forecast Discussion
Issued by NWS Quad Cities, IA IL

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000
FXUS63 KDVN 302327
AFDDVN

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
627 PM CDT SAT MAY 30 2015

.SYNOPSIS...
ISSUED AT 229 PM CDT SAT MAY 30 2015

AN OVERCAST SKY PREVAILED DURING THE AFTERNOON HOURS AS SURFACE
LOW PRESSURE MOVED THROUGH THE AREA. A NORTH TO NORTHEAST BREEZE
GUSTED AROUND 30 MPH AS COOLER AND DRIER AIR BEGAN TO OVERSPREAD
EASTERN IOWA AND NORTHERN ILLINOIS. SCATTERED SHOWERS LINGERED
MAINLY EAST OF THE MISSISSIPPI RIVER. TEMPERATURES AT 3 PM CDT
RANGED FROM THE MID 50S ALONG THE HIGHWAY 20 CORRIDOR...TO AROUND
70 DEGREES IN WEST CENTRAL ILLINOIS.

&&

.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 229 PM CDT SAT MAY 30 2015

SCATTERED SHOWERS MAINLY EAST OF THE MISSISSIPPI RIVER WILL
CONTINUE TO WIND DOWN THROUGH LATE AFTERNOON AS AN INVERTED
SURFACE TROUGH DROPS SOUTH OUT OF THE AREA. SOME QUESTION AS TO
THE TIMING OF THE CLEARING TREND TONIGHT WITH DRY NORTHEASTERLY FLOW
ADVECTING INTO THE FORECAST AREA. THE 18Z WRF WOULD DELAY THE
CLEARING ACROSS THE SOUTH UNTIL SUNDAY MORNING...SO EVENING TRENDS
WILL BEAR WATCHING.

AFTER EARLY MORNING LOWS MAINLY IN THE 40S...EXPECT A DRY AND
PLEASANT DAY ON SUNDAY WITH HIGHS MAINLY IN THE 60S...ROUGHLY 10
DEGREES BELOW NORMAL FOR THE DATE.

.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 229 PM CDT SAT MAY 30 2015

SUNDAY NIGHT THROUGH TUESDAY...12Z MODEL RUNS IN GOOD AGREEMENT OF
SUGGESTING SEASONABLY ROBUST NORTHERN GRT LKS RIDGE TO CONTINUE TO
SQUEEZE DRY/COOL NORTHEASTERN FLOW ACRS THE AREA THRU MON EVENING.
SUNDAY NIGHT TO BE COOL WITH MANY 40-45 DEGREE LOW TEMP READINGS TO
OCCUR...AND IF SFC WINDS GO LIGHTER THAN ANTICIPATED MORE UPPER 30S
MAY OCCUR ACRS THE NORTH AND NORTHEASTERN COOL AIR DRAINAGE
LOCATIONS OF THE CWA BY EARLY MON MORNING. WEAKER MIXING DAY MON
WITH MANY UPPER 60 TO AROUND 70 DEGREE HIGHS. WESTERN INTO CENTRAL
GRT LKS LLVL ANTICYCLONE MAINTAINS MON NIGHT INTO TUE WHILE A BOUT
OF UPPER RIDGING TAKES SHAPE ACRS THE PLAINS TOWARD THE MID/UPPER MS
RVR VALLEY FOR CONTINUED FAIR BUT BELOW NORMAL TEMP WX REGIME. FCST
LOWS FOR MON NIGHT MAY NOT BE COOL ENOUGH. SLIGHT EAST-SOUTHEAST
LLVL FLOW COMPONENT CHANGE...AS WELL AS COLUMN MODIFICATION MAY ALLOW
FOR A WARM UP INTO THE LOW TO MID 70S ON TUE. BOTH THE 12Z RUN GFS
AND ECMWF NOW LINGER THE RIDGING FURTHER TO THE WEST FOR MORE
CONFIDENCE IN REMOVING ANY TUE NIGHT POPS IN THE WEST.

WEDNESDAY AND THURSDAY...BOTH THE 12Z GFS AND ECMWF ADVERTISE A TYPE
OF REX BLOCK ACRS THE EASTERN THIRD TO HALF OF THE CONUS THIS
PERIOD...WHILE RETURN FLOW/MID LEVEL SOUTHWESTERLIES ACTIVATE ACRS
THE CENTRAL TO NW HIGH PLAINS...AS WELL AS INTO MN. MORE
THERMODYNAMICALLY FAVORED SET-UP FOR AIR MASS TYPE SCTRD SHOWERS/
STORMS CLOSER TO DAMPENING UPPER LOW ACRS THE OH RVR VALLEY INTO TN
VALLEY REGIONS...THUS THE DVN CWA COULD BE IN BETWEEN THE
SYNOPTICALLY ACTIVE ZONES AND BE MAINLY DRY UNTIL POSSIBLE THU NIGHT
WHEN A DECAYING STORM CLUSTER OR MCS TYPE FEATURE TRIES TO BLEED
INTO THE WESTERN TO NORTHWESTERN CWA FROM THE MO RVR VALLEY. BUT EVEN
LOW CONFIDENCE IN THIS SCENARIO WITH BETTER SUPPORT OFF TO THE
NORTHWEST THRU FRI MORNING. TEMPS CONTINUE TO MODERATE THROUGH MID
WEEK WITH A RETURN TO THE 80S BY THU.

NEXT FRIDAY AND SATURDAY...LONGER RANGE GUIDANCE AND LATEST MREF
SUGGEST THE UPSTREAM UPPER RIDGE TO DAMPEN UNDER THE GUN FROM
ONGOING SHORT WAVE INFLUX OUT OF THE WEST THIS PERIOD...WITH SOME
SIGNS OF A LLVL WEST-TO-EAST ORIENTED WARM FRONT OR FRONTS SETTING UP
IN OR NEAR THE LOCAL FCST AREA INTO THE START OF THE WEEKEND. WITH
ONGOING WARM MOIST CONVEYOR SHIFTING MORE EAST UP INTO THE UPPER
MIDWEST...THESE FACTORS SUPPORT AN INCREASE IN POPS FOR MORE
CONVECTIVE ACTIVITY LATE IN THE FCST CYCLE. LOW CONFIDENCE WHERE THE
MAIN HALF RING OF LLVL BAROCLINICITY WILL LAY OUT TO FOCUS MORE
WIDESPREAD AND FREQUENT STORM ACTIVITY AT THIS POINT...BUT THE NEW
EURO TARGETS THE SOUTHERN CWA FROM LATE SAT INTO SUNDAY. ..12..

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING)
ISSUED AT 623 PM CDT SAT MAY 30 2015

LOW PRESSURE WILL CONTINUE TO MOVE AWAY FROM THE REGION
TONIGHT...WITH DRY AIR FLOWING INTO THE REGION HELPING IMPROVE THE
WIDESPREAD MVFR CLOUD COVER TO CLEAR CONDITIONS BETWEEN 02Z AND
05Z THIS EVENING. WINDS WILL DECREASE WITH SUNSET TO AROUND 10 KTS
FROM THE NORTH NORTHEAST...LASTING THROUGH SUNDAY. AFTER SKIES
CLEAR TONIGHT...CONFIDENTLY CLEAR CONDITIONS WILL CONTINUE THROUGH
THE DAY SUNDAY.
ERVIN

&&

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

$$

SYNOPSIS...RP KINNEY
SHORT TERM...RP KINNEY
LONG TERM...12
AVIATION...ERVIN



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