Area Forecast Discussion
Issued by NWS Quad Cities, IA IL

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FXUS63 KDVN 311742
AFDDVN

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
1242 PM CDT SUN MAY 31 2015

.UPDATE...
ISSUED AT 1240 PM CDT SUN MAY 31 2015

HIGH PRESSURE RIDGE AND DRIER AIR WAS WINNING OUT AS THE LOW
STRATUS CONTINUES TO ERODE FROM THE NORTH...AND WAS CONFINED TO
OUR FAR SOUTHERN COUNTIES SHORTLY AFTER THE NOON HOUR. ELSEWHERE
ACROSS THE CWA FULL SUNSHINE WAS NOTED WITH 12 PM TEMPERATURES ON
THE COOL SIDE FOR THE LAST DAY OF MAY...IN THE LOWER 50S TO LOWER
60S. TEMPERATURES APPEAR ON TARGET FOR AFTERNOON HIGHS IN THE 60S.

UPDATE ISSUED AT 908 AM CDT SUN MAY 31 2015

HAVE UPDATED THE SKY GRIDS TO GO MORE PESSIMISTIC WITH REGARDS TO
CLOUD COVER IN ROUGHLY OUR SOUTHEAST 1/3RD. VISIBLE SATELLITE
SHOWS STUBBORN LOW STRATUS WHICH IS ACTUALLY SPREADING WESTWARD
INTO OUR SW CWA. THE COMBINATION OF A MOIST NORTHEAST WIND OFF
LAKE MI AND HIGHER CLOUDS STREAMING IN FROM THE SOUTHWEST IS NOT
FAVORABLE FOR CLEARING SKIES. HOWEVER...THIS AFTERNOON THE STRONG
LATE MAY SUN ANGLE AND THE SURFACE RIDGE EDGING CLOSER TO THE AREA
FROM THE WEST SHOULD ALLOW FOR AT LEAST PARTLY SUNNY SKIES. I HAVE
ALSO LOWERED MAXIMUM TEMPERATURES A COUPLE OF DEGREES IN OUR
SOUTHEAST DUE TO THE EXTENSIVE LOW CLOUDS LINGERING THROUGH THE
EARLY AFTERNOON HOURS.

OUR NW CWA WILL HAVE SUNNY SKIES ALL DAY CLOSER TO THE STRONGER
SUBSIDENCE AND SURFACE HIGH PRESSURE.

ELSEWHERE...A LARGE AREA OF WARM AIR ADVECTION MID/HIGH CLOUDS WAS
STREAMING ACROSS MUCH OF THE NORTHERN INTO THE CENTRAL PLAINS AND
WAS MOVING SOUTHEAST. MUCH OF THIS SHOULD THIN AS IT RUNS INTO THE
RIDGING FARTHER EAST AND AWAY FROM THE WARM ADVECTION ZONE.

&&

.SYNOPSIS...
ISSUED AT 317 AM CDT SUN MAY 31 2015

AS OF 3 AM CDT...GOES EAST 11-3.9 MICRON IR DIFFERENCE LOOP OVER
THE PAST FEW HOURS SHOWED A LOW-LEVEL STRATUS DECK ERODING FROM
NORTH TO SOUTH ACROSS E IOWA/W ILLINOIS. MUCH HIGHER UP...A BAND
OF CIRRUS CLOUDS WERE NOTED MOVING IN THE OPPOSITE DIRECTION OF
THE STRATUS AND HAVE NOW REACH AS FAR NORTH AS SOUTHERN IOWA AND
WEST-CENTRAL ILLINOIS.

LOCAL METAR OBS WERE REPORTING NNE/NE WINDS AROUND 10 KTS AND MAINLY
CLEAR SKIES EXCEPT ALONG AND SOUTH OF HIGHWAY 34 WHERE THE BACK EDGE
OF THE STRATUS CLOUDS WAS STILL LINGERING. TEMPS WERE IN THE UPPER
40S ON AVG ACROSS THE FORECAST AREA.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 317 AM CDT SUN MAY 31 2015

TODAY...SFC HIGH PRESSURE ACROSS THE UPPER MIDWEST AND GREAT LAKES
REGION WILL SET UP A NICE DAY FOR E IOWA/W ILLINOIS. WITH PLENTY OF
SUNSHINE HIGH TEMPS SHOULD REACH THE MID TO UPPER 60S. DEWPOINTS ARE
FORECAST TO HOLD DOWN INTO THE 40S MAKING IT FEEL VERY COMFORTABLE.
DAYTIME MIXING WILL ALLOW THE BOUNDARY LAYER TO REACH NEAR 850MB
WHERE WINDS WILL BE SUSTAINED OUT OF THE ENE AT 20 KTS...SO EXPECT
STEADY NE WINDS AT THE SFC BETWEEN 12-18 MPH AND GUSTS NEAR OR
SLIGHTLY OVER 20 MPH THROUGH THE AFTN.

TONIGHT...PRESSURE GRADIENT WILL BE LIGHTER THAN IT WAS SATURDAY
NIGHT BUT STILL DO NOT SEE SFC WINDS COMPLETELY DECOUPLING...RATHER
REMAINING NEAR 5 KTS. THERE WILL LIKELY BE PATCHY MID-LEVEL CLOUDS
THROUGH THE NIGHT AS WELL ASSOCIATED WITH A WEAK AND MOISTURE
STARVED UPPER DISTURBANCE. LOW TEMPS ARE FORECAST TO RANGE FROM THE
UPPER 30S TO LOWER 40S FOR FAR NE IOWA/NW ILLINOIS TO THE UPPER
40S IN THE SOUTHERN PORTION OF THE FORECAST AREA.

.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 317 AM CDT SUN MAY 31 2015

SURFACE HIGH PRESSURE OVER THE GREAT LAKES AND AN INCOMING UPPER
LEVEL RIDGE TO CONTINUE COOL AND DRY CONDITIONS MONDAY AND MONDAY
NIGHT. A WARMING TREND THEN FOLLOWS...SENDING TEMPERATURES BACK TO
NEAR AND THEN ABOVE NORMAL READINGS MID TO LATE WEEK. MODELS DEPICT
A DEVELOPING BLOCKING UPPER LEVEL PATTERN...WHICH CONTINUES TO
PRESENT A CHALLENGING PRECIPITATION FORECAST. OVERALL...THE SETUP
CONTINUES TO INDICATE THE ONSET OF SIGNIFICANT RAIN AND THUNDERSTORM
CHANCES WILL HOLD OFF UNTIL LATE WEEK OR INTO THE WEEKEND.

MONDAY AND MONDAY NIGHT...DESPITE MOSTLY SUNNY SKIES...EAST WINDS
AND 850 MB TEMPERATURES IN THE SINGLE DIGITS CELSIUS SHOULD LIMIT
HIGHS TO THE 60S. THE RIDGE AXIS EXTENDING SW OVER THE FORECAST AREA
THROUGH THE NIGHT LENDS SUPPORT TO THE COLDEST GUIDANCE MINS FROM
THE LOWER 40S NORTHEAST TO AROUND 50 IN THE SOUTH.

A REX TYPE BLOCK THEN DEVELOPS FROM THE GREAT LAKES TO THE GULF
COAST TUE INTO WED...WHERE MODELS DEPICT A CLOSED UPPER LOW FORMING
OVER THE LOWER MS VALLEY EASTWARD...SOUTH OF THE GREAT LAKES RIDGE.
THE LATEST MODELS SHOW THIS EVOLVING INTO MORE OF AN OMEGA TYPE
BLOCK BY LATE WEEK WITH AN UPSTREAM RIDGE PUMPING UP OVER THE
CENTRAL U.S. AND LOW PRESSURE OVER THE DESERT SW. THIS WILL
INITIALLY KEEP THE CHANNEL OF RETURNING GULF MOISTURE FOCUSED WELL
TO THE WEST THROUGH AT LEAST MID WEEK. WITH THIS LARGELY UNFAVORABLE
SETUP...HAVE CONTINUED TO DOWNPLAY AND DELAY POPS...AND NOW HAVE
ONLY SLIGHT CHANCES CONFINED TO THE NW WED NIGHT INTO THU. BETTER
CHANCES FOR THE ENTIRE AREA ARE KEPT FOR FRIDAY INTO NEXT
WEEKEND...WHEN RETURNING DEEPER MOISTURE MAY MEET UP WITH RIDGE
TOPPING SHORTWAVES AND POSSIBLE SURFACE BOUNDARIES OVER THE
REGION.

LITTLE CHANGE WAS MADE TO PREVIOUS FORECAST TEMPERATURES. HIGHS RISE
FROM THE 70S TUE AND WED...TO MAINLY THE LOWER 80S THU THROUGH
SATURDAY WHILE MINS RETURN TO MOSTLY 60S LATE WEEK INTO THE WEEKEND
WITH THE RISING DEWPOINTS.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1240 PM CDT SUN MAY 31 2015

VFR CONDS THROUGH THIS TAF CYCLE. NORTHEAST TO EAST WINDS AROUND
10 KNOTS OR LESS.

&&

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

$$

UPDATE...HAASE
SYNOPSIS...UTTECH
SHORT TERM...UTTECH
LONG TERM...SHEETS
AVIATION...HAASE



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