Area Forecast Discussion
Issued by NWS Quad Cities, IA IL

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000
FXUS63 KDVN 212326
AFDDVN

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
526 PM CST WED JAN 21 2015

.UPDATE...
ISSUED AT 525 PM CST WED JAN 21 2015

KDVN 88D IS SHOWING AXIS OF PRECIPITATION...COINCIDING WITH THE
WEAK LOW LEVEL TROUGH...FROM ABOUT KGBG TO KOLZ LATE THIS
AFTERNOON...DRIFTING SLOWLY EAST. AUTOMATED SURFACE REPORTS WERE
INDICATING LIGHT FREEZING RAIN OR SNOW UNDER THIS AXIS...WHICH WAS NOT
HANDLED WELL BY SHORT TERM MODELS. HAVE UPDATED THE FORECAST TO
ADD LIGHT FREEZING DRIZZLE AND AREAS OF LIGHT FOG INTO THE MIX FOR
EARLY THIS EVENING...ANTICIPATING A CHANGE OVER TO VERY LIGHT SNOW
OR FLURRIES AS LOW LEVEL PROFILES SHOULD DIP ENTIRELY BELOW
FREEZING. WITH MOSTLY ABOVE FREEZING PAVEMENT TEMPERATURES AND
LIGHT NATURE OF THE PRECIPITATION...NO SIGNIFICANT ICE ACCUMULATION
IS EXPECTED.

&&

.SYNOPSIS...
ISSUED AT 250 PM CST WED JAN 21 2015

12Z UA ANALYSIS HAS A WEAK UPPER LEVEL DISTURBANCE ACROSS THE
WESTERN GREAT LAKES AND ANOTHER IN THE NORTHERN PLAINS. SATELLITE
AND RADAR TRENDS THROUGH MID AFTERNOON SHOW PLENTY OF LOW LEVEL
CLOUDS WITH POCKETS OF LIGHT SNOW AND SNOW SHOWERS.

18Z SFC ANALYSIS HAS A WEAK LOW EAST OF KMLI WITH A BOUNDARY/TROF
EAST ACROSS ILLINOIS AND ANOTHER FROM THE LOW INTO NORTHERN IOWA. A
COLD FRONT RAN FROM THE STRAITS OF MACKINAC INTO SOUTHWEST WISCONSIN
AND THEN ACROSS NORTHERN IOWA. DEW POINTS WERE IN THE 30S ACROSS THE
OHIO VALLEY INTO THE WESTERN GREAT LAKES WITH 20S ACROSS MOST OF THE
PLAINS.

&&

.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 250 PM CST WED JAN 21 2015

ISOLATED TO SCATTERED SNOW SHOWERS AND/OR FLURRIES WILL PERSIST
THROUGH THE REMAINDER OF THE AFTERNOON AND INTO THE EVENING HOURS.
AREAL COVERAGE WILL SLOWLY DECREASE AS THE OVERALL FORCING CONTINUES
TO WEAKEN. FOR THE MOST PART ANY SNOWFALL WILL BE A TRACE BUT A
LOCALIZED DUSTING MAY BE POSSIBLE IN SOME SPOTS.

AFTER MIDNIGHT...QUIET CONDITIONS WILL BE SEEN. THERE MAY OR MAY NOT
BE SOME PATCHY FOG THAT DEVELOPS DUE TO THE LIGHT WINDS PRIOR TO
SUNRISE.

QUIET AND DRY CONDITIONS WILL BE SEEN ACROSS THE AREA ON THURSDAY
WITH CLOUDS SLOWLY CLEARING DURING THE DAY. ANY PATCHY FOG THAT
DEVELOPED PRIOR TO SUNRISE WILL LIFT DURING THE MORNING.
TEMPERATURES WILL BE SLIGHTLY ABOVE NORMAL.

.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 250 PM CST WED JAN 21 2015

THE MAIN FORECAST PROBLEM FOR THE LONG TERM FORECAST IS THE SYSTEM
AFFECTING THE REGION ON SATURDAY NIGHT AND INTO SUNDAY.  CURRENT
MODEL SOLUTIONS SUGGEST THAT RAIN AND SOME SNOW ARE POSSIBLE FROM
THIS SYSTEM.  THE FREEZING LINE WILL BE ACROSS OUR AREA AND THUS
LEADS TO UNCERTAINTY IN PRECIP TYPE.

THE REST OF THE WORKWEEK LOOKS PLEASANT WITH HIGH PRESSURE MOVING
INTO THE AREA.  CLOUDS SHOULD CLEAR TOMORROW LATE AND THEN INTO
FRIDAY AND SUNDAY WITH HIGH TEMPERATURES INCREASING EACH DAY.  GOOD
AGREEMENT BETWEEN THE MODELS BACKS THIS UP AS WELL.

SUNDAY A SYSTEM FROM THE NORTH APPROACHES THE AREA.  H85 NW FLOW
ACTUALLY LEADS TO WAA ON SATURDAY AS THE LOW APPROACHES THE AREA.
LATEST MODEL TRENDS HAD BEEN TRACKING THE SYSTEM FURTHER NORTH.  THE
12Z RUNS TODAY...SPECIFICALLY THE GFS AND ECMWF HAVE SPED UP THE
SYSTEM. THE GFS APPEARS TO BE FASTER THAN THE GEFS MEAN SUGGESTING
THAT IT IS AN OUTLIER.  HOWEVER THE GFS AND ECMWF ARE TRENDING
TOWARDS AGREEMENT IN SOLUTIONS.  THE GEM HAS SLIGHTLY SLOWER TIMING
THAN THE GEFS MEAN.  WHAT THIS MEANS IS THAT GUIDANCE IS STILL ALL
OVER THE PLACE AND THE FORECAST STILL HAS UNCERTAINTY.  CURRENT
THINKING IS THAT WARM TEMPERATURES NEAR THE SURFACE WILL EXIST.
THIS WILL LEAD TO A RASN MIX OVERNIGHT ACROSS SOUTHERN PORTIONS OF
THE CWA...AND SN NORTH.  DURING THE DAY SUNDAY IT APPEARS THAT ALL
RAIN WILL START TO FALL WITH SOME SNOW MIXED IN UP NORTH.  THE EURO
PROGS ABOUT AN INCH AND HALF OF ACCUMULATION.  THINK THAT WITH THE
CURRENT THERMO PROFILES IT WOULD BE PREMATURE TO START TALKING
ACCUMULATIONS...A LOT OF UNCERTAINTIES STILL REMAIN...SO WILL NOT
SPECULATE ON THIS SHIFT.

AFTER SUNDAY THE REST OF THE LONG TERM LOOKS QUIET WITH AT TO ABOVE
AVERAGE TEMPS AGAIN.  THE ECMWF BRINGS A CLIPPER THROUGH AT THE END
OF THE PERIOD...LIKE THE GFS...HOWEVER THE GFS KEEPS US DRY AND THE
ECMWF DOES NOT.  SUPERBLEND GUIDANCE KEEPS US DRY...SO THATS WHAT
WAS USED FOR THE FORECAST.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING)
ISSUED AT 525 PM CST WED JAN 21 2015

AN AREA OF LIGHT FREEZING DRIZZLE AND LIGHT SNOW WILL IMPACT
CID...DBQ AND MLI EARLY THIS EVENING. OTHERWISE...WIDESPREAD IFR
TO LIFR CONDITIONS DUE TO LINGERING LOW CLOUDS AND FOG WILL
CONTINUE THROUGH MUCH OF THE NIGHT AS LOW LEVEL MOISTURE REMAINS
IN A RATHER STAGNANT WEATHER PATTERN. BRL IS EXPECTED TO REMAIN
ALONG THE EDGE OF THE REDUCED CONDITIONS...WITH CONDITIONS NO
LOWER THAN MVFR EXPECTED. TAFS CONTINUE TO TREND TOWARD AN
IMPROVING TREND DURING THE DAY THURSDAY...WITH CLOUD BASES LIKELY
TO LIFT AND VISIBILITIES SLOWLY IMPROVING...ESPECIALLY IN THE
AFTERNOON.

&&

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

$$

UPDATE...SHEETS
SYNOPSIS...08
SHORT TERM...08
LONG TERM...GIBBS
AVIATION...SHEETS






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