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000
FXUS63 KDVN 230814
AFDDVN

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
314 AM CDT THU MAY 23 2013


.SYNOPSIS...
ISSUED AT 253 AM CDT THU MAY 23 2013

DEFORMATION ZONE MOVING SOUTH ACROSS AREA AT 2 AM WITH AREAS OF
MOSTLY LIGHT RAIN AND DRIZZLE NOTED. DUBUQUE THOUGH IN PAST 2
HOURS HAS PICKED UP .23 INCHES. AWIPS DISTANCE AND TIME FEATURE
SHOWS END OF PRECIPITATION TO PASS QUICKLY ACROSS AREA BETWEEN
11-16Z. UPPER AIR AND SURFACE SHOWS SEASONABLY STRONG AND COOL
CANADIAN AIR MASS TO MOVE IN WITH BELOW NORMAL TEMPERATURES NEXT
24 HOURS AND THEN UNSETTLED WEATHER INTO EARLY NEXT WEEK WITH
WAVES ALONG STALLED FRONT TO OUR SOUTHEAST.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 253 AM CDT THU MAY 23 2013

TODAY...USE OF NOWCAST TOOLS SUPPORTS LIGHT RAIN AND PATCHY DRIZZLE TO
SLIDE SOUTHEAST BY MID MORNING. SKIES SHOULD CLEAR FROM NORTH TO SOUTH
BETWEEN 14-21Z AS STRONG SUBSIDENCE AND COOLER AND DRIER MOVES IN.
NORTHERLY WINDS WILL BE BREEZY AT 15 TO 25 MPH INTO LATE AFTERNOON
AS HIGHS REACH MOSTLY INTO THE MIDDLE 60S AND SOME LOWER 60S IN
THE EAST AND NORTHEAST. THESE TEMPERATURES ARE ABOUT 10 DEGREES
BELOW NORMAL.

TONIGHT...CLEAR SKIES...STRONG SUBSIDENCE AND CALM WINDS BY EARLY
OVERNIGHT HOURS WILL ALLOW FOR STRONG DECOUPLING OF BL AND MINS IN
THE NORTHEAST 1/3 AREA TO SEE UPPER 30S WITH ISOLATED COLD AIR
DRAINAGE SPOTS POSSIBLY SEEING MIDDLE 30S WITH PATCHY FROST RISK.
THIS IS THE MAIN CONCERN FOR DAY SHIFT TO REASSESS. MINS WILL BE
WITHIN 2-4 DEGREES OF RECORDS AT MLI/DBQ (SEE CLIMATE SECTION BELOW).

NICHOLS

.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 253 AM CDT THU MAY 23 2013

DRY AND COOL CONDITIONS WILL BE SEEN FRIDAY WITH TEMPERATURES BELOW
NORMAL.

INITIALLY...FRIDAY EVENING WILL BE DRY. RETURN FLOW ALOFT IS PROGGED
TO BRING MOISTURE BACK NORTH INTO THE MIDWEST. SCHC POPS WERE PLACED
IN THE EXTREME WESTERN PART OF THE CWFA DURING THE LATE EVENING
HOURS. THE BETTER LLJ AND MOISTURE RETURN IS STILL WEST OF THE CWFA
AT MIDNIGHT. THE MCS/LIFT TOOLS GENERALLY SUGGEST SOMETHING JUST
WEST OF THE CWFA AT MIDNIGHT THAT SHOULD STRATIFY OUT DUE TO THE DRY
AIR OVER THE AREA.

AFTER MIDNIGHT...THE LLJ VEERS INTO THE CWFA WITH A RESPECTABLE
THETA E GRADIENT MOVING ACROSS THE AREA. INTERNALLY...THE MODELS ARE
INDICATING SIGNIFICANT EVAPORATIVE COOLING DUE TO THE DRY AIR
FEEDING IN FROM THE EAST. THUS THE MCS THAT FORMS IN THE PLAINS
WOULD STRATIFY OUT AS IT MOVES INTO THE AREA. THE EXTREME
WEST/SOUTHWEST WOULD HAVE THE BEST POTENTIAL AT SEEING A
THUNDERSTORM WHILE THE REMAINDER OF THE AREA SHOULD SEE SHOWERS.

SATURDAY WILL BE EXTREMELY COOL WITH MAINLY STRATIFORM RAIN ACROSS
THE AREA AS STRONG EVAPORATIVE COOLING CONTINUES. ANY THUNDER WOULD
BE ACROSS THE EXTREME SOUTHWEST/SOUTH PARTS OF THE CWFA AS THE
NOCTURNAL MCS CONTINUES TO DECAY.

SATURDAY NIGHT THE NEXT DISTURBANCE WILL DEVELOP AN MCS IN THE
PLAINS THAT TOPS THE RIDGE INTO THE AREA. AGAIN RELATIVELY DRY AIR
FEEDING IN FROM THE EAST SHOULD RESULT IN THE MCS STRATIFYING OUT AS
IT REACHES THE AREA. ANY THUNDER WOULD BE ISOLATED AND ACROSS THE
SOUTH THIRD AT MOST.

SUNDAY ON...
THE MODEL CONSENSUS CONTINUES AN ACTIVE WEATHER PATTERN ACROSS THE
MIDWEST WITH NUMEROUS DISTURBANCES TOPPING THE UPPER RIDGE OVER THE
AREA. THE OVERALL SET UP IS COMPARABLE TO A MID SUMMER RING OF FIRE.
THUS MCS EVENTS ARE EXPECTED TO DEVELOP AND MOVE INTO THE AREA AT
NIGHT WITH THE MCS DECAYING ACROSS THE AREA DURING THE DAY TIME.
BOUNDARIES LEFT OVER FROM EACH MCS EVENT WILL PROVIDE THE FOCUS FOR
DIURNAL CONVECTION DURING THE AFTERNOON AND EVENING.

THE MODEL CONSENSUS HAS CHC POPS FROM SUNDAY THROUGH WEDNESDAY
REFLECTING THIS SCENARIO. THERE WILL BE PERIODS OF DRY WX BUT THEY
CANNOT BE RESOLVED DUE TO SMOOTHING OF THE MODEL FEATURES.
TEMPERATURES WILL REMAIN BELOW NORMAL ON SUNDAY FOLLOWED BY
MODERATING TEMPERATURES MONDAY THROUGH WEDNESDAY.

08

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 253 AM CDT THU MAY 23 2013

DEFORMATION ZONE WITH A SWATH OF MOSTLY IFR CONDITIONS AND AREAS
OF RAIN/DRIZZLE WILL SLIDE SOUTHEAST OF AREA BETWEEN 11-14Z AT ALL
TERMINALS. CLOUDS WILL LIFT TO MVFR CONDITIONS AND THEN CLEAR FROM
NORTH TO SOUTH BETWEEN 15-20Z. NORTHERLY WINDS OF 10 TO 20 KTS
WILL DIMINISH AROUND SUNSET AND BECOME LIGHT AFTER 05Z AS SURFACE
HIGH MOVES OVERHEAD.

NICHOLS

&&

.CLIMATE...
ISSUED AT 253 AM CDT THU MAY 23 2013

RECORD LOWS FOR MAY 24...

MOLINE.........36 IN 1925
CEDAR RAPIDS...34 IN 1925
DUBUQUE........35 IN 1925
BURLINGTON.....38 IN 1925


&&

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

&&

$$

SYNOPSIS...NICHOLS
SHORT TERM...NICHOLS
LONG TERM...08
AVIATION...NICHOLS
CLIMATE...NICHOLS