Area Forecast Discussion
Issued by NWS Quad Cities, IA IL

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000
FXUS63 KDVN 241210
AFDDVN

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
710 AM CDT SUN APR 24 2016

.UPDATE...
ISSUED AT 710 AM CDT SUN APR 24 2016

WARM AIR ADVECTION WING OF SHOWERS IN THE DVN CWA CONTINUES TO
SHIFT EAST WHILE DIMINISHING IN INTENSITY AND COVERAGE. EXPECT THE
FEW SHOWERS REMAINING IN FAR NW IL WILL BE GONE WITHIN AN HOUR OR
TWO. MEANWHILE...THUNDERSTORMS HAVE RAPIDLY FIRED WITHIN THE PAST
3 HOURS IN EXTREME EASTERN NEB AND WESTERN IA. THESE STORMS WERE
OCCURRING WHERE THE BETTER 850 MB MOISTURE TRANSPORT AND HIGHER
PWAT`S WERE LOCATED. HOWEVER...STEERING WINDS WILL TAKE THESE
STORMS NORTHEAST INTO MN. THESE STORMS WILL SPREAD EVEN MORE
CIRRUS BLOW-OFF INTO THE DVN CWA TODAY.

STUDYING THE LATEST MODEL DATA INCLUDING THE HIRES SUGGEST THE
THUNDERSTORM ACTIVITY LATER THIS AFTERNOON AND TONIGHT WILL BE
EVEN SLOWER TO ARRIVE INTO THE DVN CWA THAN EARLIER THOUGHT. THE
HRRR STILL HAS THE STORMS IN WESTERN IA AT 8 PM THIS EVENING WHILE
THE SPC 4.0 KM WRF-NMM HAS THE ACTIVITY WEAKENING RAPIDLY BEFORE
REACHING THE WESTERN CWA AND NOT UNTIL TOWARDS MIDNIGHT. AS A
RESULT I HAVE SLOWED THE PROGRESS OF THESE STORMS EVEN MORE IN THE
LATEST GRID UPDATE. OF COURSE...THIS LATER TIMING WOULD LESSEN THE
THREAT OF ANY STRONGER STORMS.

&&

.SYNOPSIS...
ISSUED AT 315 AM CDT SUN APR 24 2016

WARM AIR ADVECTION WING OF SHOWERS EXTENDED FROM SE MN INTO
NORTHEAST IA AND WAS GRAZING OUR FAR NW CWA. IR SATELLITE LOOPS
INDICATE CIRRUS SPREADING OVER THE CWA FROM THE PLAINS. 3 AM
TEMPERATURES RANGED FROM 45 AT FREEPORT TO THE UPPER 50S IN SE IA
AND EXTREME NORTHEAST MO.

ELSEWHERE...THUNDERSTORMS WERE LOCATED IN CENTRAL MN ON THE NOSE
OF A STRONG 50 KNOT LOW LEVEL JET AND NEAR A WARM FRONT LIFTING
THROUGH THE UPPER MIDWEST.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 315 AM CDT SUN APR 24 2016

FORECAST FOCUS ON A WARM DAY WITH A CHANCE OF SHOWERS AND STORMS
TONIGHT.

TODAY...OPERATIONAL MODELS SIMILAR IN SLOWING DOWN THE STORM
SYSTEM SOMEWHAT...KEEPING THE DVN CWA DRY FOR MUCH OF TODAY.
THEREFORE...HAVE REMOVED THE MENTION OF POPS FOR THIS AFTERNOON.
OTHER THAN A FEW SHOWERS IN OUR FAR NW EARLY THIS MORNING WE WILL
HAVE TO WAIT UNTIL THIS EVENING FOR RAIN CHANCES TO RETURN.
OTHERWISE...LOW PRESSURE WILL BE PUSHING INTO CENTRAL SD BY LATE
IN THE DAY WITH THE DVN CWA IN THE WARM AND WINDY SECTOR. SOUTH
WINDS WILL BE GUSTING TO OVER 30 MPH PUSHING AFTERNOON TEMPERATURES
INTO THE LOWER 80S AT MOST LOCATIONS. WOULD HAVE GONE HIGHER
BUT CIRRUS OVER THE AREA PREVENTS THAT. IF THE CIRRUS MANAGES TO
THIN OUT COMPLETELY THEN MID 80S ARE POSSIBLE FOR DAY SHIFT TO
MONITOR. EVEN THOUGH WE ARE NOT EXPECTING RECORD HIGHS THEY WILL
BE CLOSE SO HAVE ADDED A CLIMATE SECTION BELOW FOR REFERENCE.

TONIGHT...STRONG TO SEVERE THUNDERSTORMS DEVELOPING THIS AFTERNOON
IN EASTERN NEB/FAR WESTERN IA WILL GRADUALLY SPREAD EASTWARD
REACHING OUR WESTERN CWA THIS EVENING BUT PAST PEAK HEATING.
THESE STORMS SHOULD BE IN A WEAKENING FASHION BUT STILL CAN`T RULE
OUT A STRONGER STORM IN OUR FAR NW CWA ASSUMING THEY ARRIVE IN THE
EARLY EVENING HOURS BEFORE SUNSET. THEREAFTER...WITH THE LOSS OF
BOUNDARY LAYER INSTABILITY THE SCATTERED STORMS SHOULD CONTINUE
TO WEAKEN. WILL CONTINUE WITH ISOLATED TO SCATTERED COVERAGE OF
THE STORMS DURING THE NIGHT. LOW PRESSURE WILL BE PUSHING ACROSS
SOUTHERN MN KEEPING A SOUTHERLY WIND ACROSS THE CWA OVERNIGHT.
THIS WILL ALLOW FOR A MILD NIGHT WITH LOWS AROUND 60.

.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 315 AM CDT SUN APR 24 2016

MONDAY CONTINUES TO OFFER UP ONE MORE WARM LATE SPRING DAY WITH A
LOW PROBABILITY OF CONVECTION BEFORE A COOLER...AND FAR MORE
UNSETTLED WEATHER PATTERN SETS UP FOR THE MID WEEK AND BEYOND.

A BIAS CORRECTED RAW BLEND OF MODELS RESULTS IN HIGHS IN THE
UPPER 7S0 TO LOWER 80S...AND THAT SEEMS ON TARGET WITH THE
BOUNDARY NORTH OF THE CWA UNTIL EVENING...AND SKIES AT LEAST
PARTLY SUNNY THROUGH EARLY AFTERNOON. BY EVENING THE FRONT WILL
SWEEP THROUGH WITH LITTLE CONVERGENCE SHOWN IN MODEL DATA. THAT
SHOULD KEEP COVERAGE RATHER LOW...AND RAINFALL SPOTTY AT BEST.
BEHIND THIS FRONT...HIGH PRESSURE TRY TO NOSE ITS WAY SOUTH INTO
OUR CWA. THIS DRY DAY TUESDAY IS LIKELY OUR LAST CONFIDENTLY DRY
DAY IN SOME TIME AS THE PATTERN TURNS HYPERACTIVE IN A PROGRESSIVE
SYNOPTIC REGIME.

THERE IS GOOD AGREEMENT FROM RUN TO RUN WITH THE ECMWF...AND NOT THE
GFS. THEREFORE...OUR FORECAST IS LEANING HEAVILY ON THIS
CONSISTENTCY. THE GFS SHOWS SIMILAR SYNOPTIC PLACEMENT OF THE
BOUNDARIES...AND THE RATHER STRONG TEMPERATURE CONTRAST ALONG
THEM...BUT SEEMS TO FOCUS FAR TO HEAVILY ON CONVECTIVE PROPAGATION
OF PRECIPITATION FROM TUESDAY NIGHT THROUGH THURSDAY...AND THAT
SEEMS THE WRONG CHOICE HERE AS CONVECTION WILL LIKELY STRATIFY OUT
TO NEAR 100 PERCENT COVERAGE OVER OUR CWA FOR THIS EVENT.

TEMPERATURES UNDER THE RAIN AND COOL WET BULBED EASTERLY FLOW WILL
BE UNPLEASANT AT BEST...WITH HIGHS WEDNESDAY AND THURSDAY ONLY
TOPPING OUT IN THE LOWER TO MID 50S...WHICH COULD BE OPTIMISTIC IF
RAIN IS TRUELY CONTINUOUS. THE FIRST SYSTEM LOOKS TO LINGER THROUGH
THURSDAY...WITH THUNDER GENERALLY CONFINED TO THE SOUTH HALF DURING
THE EVENT.

FRIDAY IS STILL FORECAST TO BE DRY...AND MOST GUIDANCE STILL
SUPPORTS THIS...EXCEPT FOR THE 00Z ECMWF...WHICH NEVER DROPS THE
FRONT SOUTH OF THE REGION THURSDAY...THUS ONCE WARM MOIST ADVECTION
KICKS OFF ON THE NEXT ADVANCING SYNOPTIC TROF...IT GENERATE RAIN
SHOWERS AND STORMS.  THAT NEXT SYSTEM APPEARS STRONG ON BOTH THE GFS
AND ECMWF DAT TONIGHT.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 710 AM CDT SUN APR 24 2016

VFR CONDS THROUGH THIS TAF CYCLE. SOUTH WINDS INCREASING TO 15 TO
25 KNOTS WITH GUSTS TO NEAR 30 KNOTS LATER THIS MORNING THROUGH
THE AFTERNOON. SOUTH WINDS WILL DIMINISH TO AROUND 10 KNOTS
TONIGHT. SCATTERED SHOWERS AND A FEW THUNDERSTORMS MAY PUSH INTO
EASTERN IA TOWARDS MIDNIGHT.

&&

.CLIMATE...
ISSUED AT 315 AM CDT SUN APR 24 2016

RECORD HIGHS FOR APRIL 24...

MOLINE.........86 IN 1939
CEDAR RAPIDS...87 IN 2009
DUBUQUE........85 IN 1939
BURLINGTON.....85 IN 1954

&&

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

$$

UPDATE...HAASE
SYNOPSIS...HAASE
SHORT TERM...HAASE
LONG TERM...ERVIN
AVIATION...HAASE
CLIMATE...HAASE



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