Area Forecast Discussion
Issued by NWS Quad Cities, IA IL

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000
FXUS63 KDVN 231737
AFDDVN

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
1237 PM CDT SAT MAY 23 2015

.UPDATE...
ISSUED AT 1236 PM CDT SAT MAY 23 2015

INCREASING MID AND UPPER LEVEL MOISTURE IS RUNNING INTO THE 500
MB RIDGE AXIS FROM THE OHIO RIVER VALLEY INTO THE WESTERN GREAT
LAKES...RESULTING IN MOSTLY SUNNY SKIES OVER MUCH OF THE FORECAST
AREA SO FAR TODAY. ELEVATED SPOTTY SHOWERS SHOWING UP ON AREA
RADARS IN CENTRAL IA AND SE IA WERE BASED ABOVE 7000 FT AND NOT
LIKELY REACHING THE GROUND.

HAVE UPDATED THE FORECAST FOR MORE SUNSHINE THIS AFTERNOON WITH
HIGH TEMPERATURES STILL ON TRACK TO REACH THE UPPER 70S TO
AROUND 80 OVER THE AREA. DEWPOINTS WILL REMAIN ONLY IN THE UPPER
40S TO LOWER 50S...RESULTING IN COMFORTABLY LOW HUMIDITY LEVELS
FOR LATE MAY.

&&

.SYNOPSIS...
ISSUED AT 255 AM CDT SAT MAY 23 2015

HIGH PRESSURE WAS ENTRENCHED ACROSS THE AREA THIS MORNING. THE
STRONGEST HIGH WAS LOCATED OFF TO OUR EAST. THIS WAS LEADING TO A
LIGHT EASTERLY WIND ACROSS OUR EASTERN AREA. HIGH LEVEL MOISTURE
LEAD TO CIRRUS CLOUDS ACROSS THE AREA. THIS MOISTURE WAS THE
RESULT OF A SOUTH SOUTHWEST FLOW AT THE UPPER LEVELS. THIS FLOW
AND RIPPLES THROUGH THE FLOW WILL BE THE DOMINATE WEATHER PRODUCER
THROUGH THE HOLIDAY WEEKEND.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 255 AM CDT SAT MAY 23 2015

MAIN FORECAST CONCERN FOR THE SHORT TERM ARE THE CHANCES FOR
PRECIPITATION TONIGHT. THE PRECIPITATION GRADIENT WILL BE LOCATED
SOMEWHERE ACROSS THE CWA...MAKING FOR A DIFFICULT FORECAST.

DURING THE DAY TODAY...HIGH LEVEL CLOUDS SHOULD PERSIST. WAA INTO
THE AREA AND INSOLATION WILL HELP TO INCREASE TEMPERATURES ACROSS
THE AREA TODAY INTO THE MID AND UPPER 70S. A FEW SITES MAY EVEN
BREAK THE 80 DEGREE MARK. H5 RIDGING WILL MOVE THROUGH THE AREA
TODAY AND EVEN THROUGH THE OVERNIGHT HOURS. THE FLOW WILL THEN
TURN SOUTH TO SOUTHWEST. THIS WILL LEAD TO MOISTURE ADVECTION
INTO THE AREA. TODAY WILL BE THE LAST DAY OF THE WEEKEND WITH NO
POPS.

TONIGHT...H5 RIDGING SHOULD OCCUPY MOST OF THE CWA THROUGH 12Z.
THIS...SHOULD HELP TO LIMIT OVERALL POPS FOR THE NIGHT. SPECTRAL
MODELS SUGGEST THAT WE WILL SEE PRECIP OVER MOST OF THE AREA FROM
6Z TO 12Z SUNDAY AM. THE NAM SUGGESTS THAT MOST OF THE PRECIP WILL
BE WEST OF THE MISSISSIPPI RIVER. MODEL REFLECTIVITY FROM THE
WRFARW AND WRFNMM SUPPORTS THIS NOTION AS WELL. AS FAR AS I CAN
TELL...THE NAM AND AND WRF MODELS HAVE A BETTER HANDLE ON COVERAGE
ACROSS THE CWA. THIS MEANS THAT RAIN WILL LIKELY STAY WEST OF
MISSISSIPPI RIVER THROUGH 12Z SUNDAY. A LACK OF INSTABILITY
SUGGESTS THAT THIS WILL BE MOSTLY RAIN. I CANNOT RULE OUT AN
ISOLATED THUNDERSTORM WITH THIS FLOW. I PUT THUNDER IN THE
FORECAST FOR ANY AREA THAT HAS A CHANCE OR GREATER FOR PRECIP.

.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 255 AM CDT SAT MAY 23 2015

NEAR TO SLIGHTLY ABOVE NORMAL TEMPS AND UNSETTLED WITH PERIODIC
BOUTS OF SHOWERS AND SOME STORMS.

SUNDAY AND SUNDAY NIGHT...HIGHER POPS TARGETING MAINLY WESTERN 1/2-
2/3 OF CWA ESPECIALLY SUNDAY AM WITH VEERING LOW LEVEL JET AND
ATTENDANT MOIST ADVECTION AND CONVERGENCE. THEN...CONTINUED CHANCES
SUNDAY AFTERNOON WITH MOIST AXIS (PWATS 1.5-1.75 INCHES) AND
POTENTIAL PERTURBATIONS EMBEDDED IN SOUTHWEST FLOW ALOFT. PERHAPS
SECONDARY FOCUS OF HIGHER POPS ARRIVING SUNDAY NIGHT WITH SHORTWAVE
TROUGH LIFTING INTO THE UPPER MIDWEST.

MEMORIAL DAY AND MONDAY NIGHT... MORE AGREEMENT THAT MEMORIAL
DAY HARBORS A MUCH LOWER POTENTIAL FOR PCPN AS FLOW VEERS
WESTERLY USHERING IN SLIGHT DRYING AND SHIFTING MAIN MOIST AXIS
TO OUR EAST... WHILE MAIN FORCING ATTENDANT TO SHORTWAVE TROUGH
LIFTING AWAY FROM REGION. THUS MEMORIAL DAY OVERALL SHOULD HAVE
MANY DRY HOURS... BUT WARM AND MUGGY CONDITIONS WITH HIGHS AROUND
80 OR LOWER 80S AND DEWPTS WELL IN THE 60S. PCPN CHCS LOOK TO
INCREASE AGAIN MONDAY NIGHT AS SECONDARY DISTURBANCE MOVES
THROUGH THE MID- MISSISSIPPI VALLEY... AND ATTENDANT WEAK SURFACE
COOL FRONT SAGS INTO THE REGION BY TUESDAY AM.

TUESDAY THROUGH FRIDAY... SOME INDICATIONS OF POSSIBLY ANOTHER DRIER
PERIOD DEVELOPING BY WEDNESDAY OR WEDNESDAY NIGHT WITH PASSAGE OF
WEAK FRONT AND INCREASING HEIGHTS ALOFT IN WAKE OF UPPER LEVEL
SHORTWAVE. PATTERN THOUGH LOOKS TO RELOAD AND TURN ACTIVE YET AGAIN
LATTER HALF OF THE WEEK AND JUST BEYOND WITH GULF MOISTURE
INCREASING AHEAD OF ANOTHER PLAINS TROUGH.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1236 PM CDT SAT MAY 23 2015

VFR CONDITIONS AND LIGHT SOUTH WINDS WILL CONTINUE THIS AFTERNOON
THROUGH TONIGHT UNDER GRADUALLY INCREASING MID AND HIGH LEVEL
CLOUDS. SUNDAY...INCREASING MOISTURE AND AN UPPER LEVEL SYSTEM
MOVING OUT OF THE PLAINS WILL BRING INCREASING CHANCES FOR
SHOWERS. OVERALL...THE TIMING AND COVERAGE OF SHOWERS AND
ISOLATED THUNDERSTORMS IS LOW CONFIDENCE AND GREATLY DEPENDENT ON
WHAT OCCURS TODAY INTO THIS EVENING IN THE PLAINS. BECAUSE OF
THIS...PROB30 GROUPS AND TEMPO GROUPS WERE INCLUDED ONLY IN THE
FINAL 3 TO 4 HOURS OF THE TAFS FOR SHOWERS WITH FLIGHT
RESTRICTIONS NO LOWER THAN MVFR THIS CYCLE.

&&

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

$$

UPDATE...SHEETS
SYNOPSIS...GIBBS
SHORT TERM...GIBBS
LONG TERM...05
AVIATION...SHEETS



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