Area Forecast Discussion
Issued by NWS Quad Cities, IA IL

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000
FXUS63 KDVN 202031
AFDDVN

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
331 PM CDT MON OCT 20 2014

.SYNOPSIS...
ISSUED AT 330 PM CDT MON OCT 20 2014

12Z UA ANALYSIS HAS A SHORTWAVE MOVING THROUGH THE GREAT LAKES WITH
AN 850MB COLD FRONT FROM UPPER MICHIGAN INTO NORTHERN MINNESOTA.
SATELLITE TRENDS THROUGH MID AFTERNOON SHOWS SOME DIURNAL CLOUDS
DEVELOPING ON THE WESTERN EDGE OF SYSTEM CLOUDS.

18Z SFC ANALYSIS HAS A COLD FRONT RUNNING FROM NORTHERN LAKE HURON
INTO SOUTHEAST MISSOURI. A POST FRONTAL TROF RAN FROM KHTL INTO
EASTERN IOWA. DEW POINTS WERE IN THE 30S AND 40S ACROSS THE PLAINS
AND WESTERN GREAT LAKES WITH 50S FROM THE OHIO VALLEY INTO THE
SOUTHERN PLAINS.

&&

.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 330 PM CDT MON OCT 20 2014

QUIET AND DRY CONDITIONS WILL BE SEEN TONIGHT AND TUESDAY. THE AREA
WILL START OUT WITH CLEAR SKIES AT SUNSET. LATE TONIGHT FLOW
DEVELOPS OFF LAKE MICHIGAN WHICH MAY INDUCE LOW CLOUDS ACROSS
NORTHEAST ILLINOIS THAT SLOWLY MOVES WEST. IF THIS OCCURS...AREAS
EAST OF THE MISSISSIPPI AND ALONG/NORTH OF I-80 MAY SEE LOW CLOUDS
MOVE BACK INTO THE AREA JUST PRIOR TO SUNRISE.

ON TUESDAY...ANY LOW CLOUDS THAT MOVE INTO THE EASTERN HALF OF THE
AREA WILL STOP THEIR WESTWARD MOVEMENT AFTER SUNRISE. DIURNAL
HEATING DURING THE DAY WILL INDUCE MIXING TO THIN OUT THESE CLOUDS
WHILE DEVELOPING SOME AFTERNOON CLOUDS ACROSS THE REMAINDER OF THE
AREA. TEMPERATURES SHOULD AVERAGE A LITTLE BELOW NORMAL WITH
READINGS IN THE 50S.    ..08..


.LONG TERM...(TUESDAY NIGHT THROUGH NEXT MONDAY)
ISSUED AT 330 PM CDT MON OCT 20 2014

TUESDAY NIGHT THROUGH THURSDAY...12Z MEDIUM RANGE GUIDANCE IN GOOD
AGREEMENT OF OMEGA UPPER RIDGE SLIDING ACRS THE MS RVR VALLEY EARLY
THIS PERIOD...WITH BACKDOOR SFC HIGH HAVING INFLUENCE ACRS THE
WESTERN GRT LKS AND OUR LOCAL AREA. COOLER/DRIER SFC DPTS IN
DECREASING EAST/NORTHEASTERLY BOUNDARY LAYER FLOW COULD SET THE
STAGE FOR A CHILLY NIGHT TUE INTO WED MORNING WITH LOWS IN THE LOW
TO MID 30S ACRS THE NORTHEASTERN TWO THIRDS OF THE DVN CWA. MORE
FROST AND LOW LYING/VALLEY FOG AS WELL. LARGE DIURNAL SWING UNDER
PLENTIFUL INSOLATION ON WED WITH HIGHS IN THE MID 50S TO AROUND 60.
SIGNALS OF INCREASING MOIST CONVEYOR UP TO THE LEE OF APPROACHING
UPSTREAM TROF COMPLEX ARE THERE ENOUGH TO BUMP UP POPS FOR SHOWERS
ACRS THE NORTHWESTERN THIRD OF THE CWA BY LATE WED NIGHT. FROPA AND
ASSOCIATED SHOWERS TO CONTINUE TO PUSH THROUGH THE AREA ON THU
PROBABLY IN A DECAYING FASHION. THE 12Z RUN NAM AND GFS SUGGEST
PWAT/S INCREASING TO 0.80 TO NEAR AN INCH BY THU MORNING...BUT
PROBABLY OVERDOING LLVL MOISTURE RETURN. BUT EVEN UNDERCUTTING THIS
SATURATION AND TAKING INTO ACCOUNT SOME DECREASE IN PRECIP INTENSITY
AS IT TRANSLATE ACRS THE CWA THU...SEVERAL AREAS/MAINLY WEST OF THE
MS RVR/ STILL TO GET FROM 0.10 TO 0.30+ OF AN INCH OF RAIN BY LATE
THU AFTERNOON. CLOUDS AND PRECIP TO HOLD TEMPS IN THE 50S TO NEAR 60
THU DESPITE PREF-FRONTAL WAA SURGE. SOME LINGERING LIGHT RAIN OR
SPRINKLES IN THE EAST THU EVENING...AND ANY CLEAR OUT WITH LIGHT
CONVERGENT SFC RETURN FLOW MAY FOSTER SOME FOG BY EARLY FRI MORNING.

FRIDAY THROUGH NEXT MONDAY...LONGER RANGE INDICATIONS BY ENSEMBLES
STILL PAINT BROAD BUILDING UPPER RIDGE ACRS MUCH OF THE WESTERN 2/3S
OF THE CONUS BY THE WEEKEND. ACTIVE FLOW AROUND THE PERIPHERY OF
THIS FEATURE ACRS CANADA TO SHUTTLE ANOTHER VIGOROUS WAVE DOWN
TOWARD THE NORTHWESTERN GRT LKS FRI INTO SAT...WAA TO THE SOUTH OF
THIS PROCESS TO INCREASE ACRS THE LOCAL AREA FRI WITH HIGHS BY LATE
AFTERNOON IN THE MID TO UPPER 60S IN MUCH OF THE AREA...AND THAT MAY
BE CONSERVATIVE. POTENT WAVE ENERGY IN THE PACIFIC NORTHWEST TO
PUMMEL ITS WAY INLAND THIS WEEKEND WITH AID OF STRONG WEST-SOUTHWEST
UPPER JET-LET. MASS RESPONSE OF UPPER RIDGE GET PRESSED EASTWARD TO
ALLOW SOME OF BUILDING THERMAL RIDGE ACRS THE PLAINS TO MAKE IT ACRS
THE LOCAL AREA SAT AND ESPECIALLY ON SUNDAY. WEAK MIXING UNDER
PASSING LLVL ANTICYCLONE MAY LIMIT THE WARM-UP POTENTIAL ON SAT IN
THE UPPER 60S TO MID 70S...BUT STRENGTHENING RETURN FLOW SIGNAL THERE
ON SUNDAY AHEAD OF APPROACHING L/W TROF AXIS MIGRATING EASTWARD ACRS
THE WESTERN ROCKIES. CURRENTLY PROGGED WARM AIR ADVECTION AND
MARGINAL MIXING SUPPORT HIGHS SUNDAY IN THE MID TO UPPER 70S. THE
AIRMASS PROGGED TO BE ARRIVING BY SUNDAY WOULD WARM UP INTO THE LOW
TO MID 80S IF IT WHERE AUGUST OR EARLY SEPT. UNCERTAINTY INCREASES
FROM SUNDAY NIGHT INTO EARLY NEXT WEEK WITH TIMING OF UPPER TROF
PASSAGE AND ASSOCIATED SFC FRONT UNDER IT. LLVL RETURN FLOW MOISTURE
AND INSTABILITY ALSO IN DIFFERING VIEWS BY THE 12Z RUN ECMWF/UKMET
AND GFS. THE AGGRESSIVE GFS SPAWNS SCTRD SHOWERS AND THUNDERSTORMS
ACRS THE CWA AHEAD OF THE FROPA FROM LATE SUNDAY NIGHT AND MONDAY...
WHILE THE ECMWF IS ADVERTISING A DRY FROPA BY MONDAY AFTERNOON. FEEL
IT WILL BE IN BETWEEN THESE SOLUTIONS AND FOR NOW WILL GO WITH SLIGHT
CHC POPS LATE SUN NIGHT AND MONDAY FOR NOW.     ..12..

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1234 PM CDT MON OCT 20 2014

VFR CONDITIONS WILL BE SEEN THROUGH 06Z/21. AFT 06Z/21 VFR
CONDITIONS ARE EXPECTED TO CONTINUE. HOWEVER...FLOW OFF LAKE
MICHIGAN COULD PUSH MVFR CIGS INTO KDBQ BY 12Z/21 AND NEAR KMLI.
FOR NOW A SCATTERED DECK OF 2KFT AGL WAS PUT INTO THE 18Z TAFS.

&&

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

$$

SYNOPSIS...08
SHORT TERM...08
LONG TERM...12
AVIATION...08






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