Area Forecast Discussion
Issued by NWS Quad Cities, IA IL

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FXUS63 KDVN 020432
AFDDVN

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
1132 PM CDT FRI MAY 1 2015

.SYNOPSIS...
ISSUED AT 218 PM CDT FRI MAY 1 2015

WEAK FLOW CONTINUES AT THE SURFACE TODAY...AS A TROF SLOWLY
PROGRESSES EAST THROUGH WESTERN IOWA...INTO A BROAD WEAK HIGH
PRESSURE SYSTEM. THE RESULT OF THIS PROCESS HAS BEEN AND WILL
CONTINUE TO BE BANDS OF MID AND HIGH CLOUDS...WITH ANY SPRINKLES
FOUND WEST OF OUR COUNTIES IN IOWA. THE LIGHT WINDS...AND PARTLY
SUNNY SKIES HAVE BROUGHT A REMARKABLY PLEASANT DAY THUS FAR...WITH
MID AFTERNOON TEMPERATURES IN THE MID 60S TO AROUND 70.

&&

.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 218 PM CDT FRI MAY 1 2015

THE TROF TO THE WEST WILL ADVANCE EAST AND WEAKEN...AND BE ABSORBED
INTO A BROAD SOUTHERLY FLOW ON THE WESTERN SIDE OF THE DEPARTING
SURFACE HIGH PRESSURE SYSTEM TONIGHT. WITH DRY AIR IN PLACE...IT
APPEARS OUR ENTIRE AREA WILL BE DRY THROUGH THE NIGHT...AND LIKELY
THROUGH SATURDAY AS WELL. THESE APPEAR TO BE THE LAST CONFIDENTLY
DRY PERIODS THROUGH MUCH OF THE UPCOMING WEEK. I HAVE INCLUDED SOME
SLIGHT CHANCE POPS ALONG OUR FAR WESTERN COUNTIES AS MOISTURE
TRANSPORT AIMED TOWARD WESTERN AND CENTRAL IOWA COULD BRING A
SPRINKLE OR EVEN A DISSIPATING LIGHT THUNDERSHOWER EASTWARD INTO
THOSE AREAS BEFORE DYING COMPLETELY SATURDAY AFTERNOON.
OTHERWISE...IN THE PARTLY TO MOSTLY CLOUDY SKY AND SOUTH WINDS...WE
SHOULD MIX TO A HIGH IN THE MID 70S IN MOST LOCATIONS. SOME CENTRAL
AREAS MAY SEE ENOUGH SUNSHINE AND MIXING TO REACH AROUND 77...AND
WITH INCREASING DEWPOINTS TO THE MID TO UPPER 40S...THE DRY FEEL TO
THE AIR MAY BECOME LESS APPARENT BY LATE AFTERNOON.

ERVIN

.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 218 PM CDT FRI MAY 1 2015

MAIN FORECAST CONCERN FOR THE EXTENDED FORECAST ARE THE CHANCES FOR
RAIN AND THUNDER STARTING THIS WEEKEND AND LASTING THROUGH THE
EXTENDED.  IT APPEARS THE TRANSITION TO A MORE MOIST REGIME IS STILL
ON TRACK.  THE DETAILS IN THE FORECAST APPEAR TO BE MESOSCALE IN
NATURE...AS SUCH CORRECT FORECASTS WILL BE DRIVEN BY CONVECTION THE
PREVIOUS DAY.  EXPECT FORECAST SPECIFICS TO CHANGE AS EACH DAY
APPROACHES.

OVERALL LARGE SCALE SYNOPTIC PATTERN WILL NOT PROVIDE FOCAL POINTS
FOR RAIN OR CONVECTION THIS WEAK.  RATHER WEAK IMPULSES IN THE FLOW
WILL TRANSVERSE THE AREA. HOWEVER...NO WELL DEFINED TROF OR SHRTWV
ARE FORECAST TO MOVE THROUGH THE AREA.  ZONAL H5 FLOW WILL GIVE WAY
TO SW FLOW THROUGH THE END OF THE PERIOD.  AT THIS TIME....MID WEEK
NEXT WEEK APPEARS TO BE THE FIRST INSTANCE OF A DECENT SHRTWV
ADVECTING INTO THE MIDWEST AND UPPER PLAINS.

THIS WEEKEND...A STEADY H85 WIND MAXIMA IS FOCUSED ON THE AREA
THROUGH MONDAY.  THIS SYSTEM WILL HELP TO FUNNEL MOISTURE INTO THE
AREA.  AN EAST-WEST BOUNDARY WILL SAG TO THE SOUTH AND SERVE AS
FOCAL POINT FOR RAIN AND THUNDERSTORMS.  GUIDANCE SUGGESTS THAT QPF
WILL FALL EITHER NORTH OR SOUTH OF THE AREA.  THE BEST MESOSCALE
FEATURES SUGGEST THAT SUNDAY NIGHT THROUGH MONDAY NIGHT APPEAR TO
HAVE A HIGH LIKELIHOOD OF BEING A WET PERIOD ACROSS THIS AREA.  PWAT
VALUES ARE OVER AN INCH ARE OVER THE AREA DURING THIS TIME.  THE
BOUNDARY SHOULD SAG SOUTH ACROSS THE AREA THROUGH MONDAY AND INTO
MONDAY NIGHT.  AT THIS TIME...SUNDAY NIGHT AND MONDAY NIGHT LOOK
LIKE THE BEST CHANCES FOR RAIN.  AMOUNTS WILL DICTATED BY THE
POSITION OF THIS BOUNDARY DURING THIS TIME.

INTO NEXT WEEK...WE SEE A CHANCE FOR RAIN AND THUNDER ALL DAYS.
WITH A LACK OF SHEAR BEING FORECAST...DO NOT SEE A CHANCE FOR
ANYTHING MORE THAN A STRONG THUNDERSTORM AT THIS TIME.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1130 PM CDT FRI MAY 1 2015

VFR CONDITIONS THE NEXT 24 HOURS. WEAK HIGH PRESSURE WILL MOVE EAST
ALLOWING FOR UPPER AIR DISTURBANCES TO PRODUCE MOSTLY SCT-BKN COVERAGE
OF MID/HI CLOUDS WITH CIGS AOA 10K AGL. ISOLATED SPRINKLES NOT OUT
OF THE QUESTION BUT COVERAGE PRECLUDES MENTIONING ATTM WITH BRL TERMINAL
MOST AT RISK FOR LIGHT SPRINKLES INTO SATURDAY EVENING. SOUTHERLY WINDS
OF 5 TO 10+ KTS THROUGH THE PERIOD.

&&

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

&&

$$

SYNOPSIS...ERVIN
SHORT TERM...ERVIN
LONG TERM...GIBBS
AVIATION...NICHOLS


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