Area Forecast Discussion
Issued by NWS Quad Cities, IA IL

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FXUS63 KDVN 182355 CCA
AFDDVN

AREA FORECAST DISCUSSION...CORRECTED SYNOPSIS AND SHORT TERM
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
535 PM CST TUE NOV 18 2014

.SYNOPSIS...
ISSUED AT 319 PM CST TUE NOV 18 2014

12Z UA ANALYSIS HAS THE 850MB ARCTIC FRONT FROM THE EAST COAST DOWN
TO THE GULF COAST. SEVERAL SHORTWAVE TROFS RAN FROM THE EASTERN
GREAT LAKES INTO THE UPPER MIDWEST AND NORTHERN PLAINS. NEXT CLIPPER
TYPE SYSTEM WAS EXITING THE NORTHERN ROCKIES AND MOVING INTO THE
PLAINS. SATELLITE/RADAR TRENDS THROUGH MID AFTERNOON SHOW PLENTY OF
DIURNAL CLOUDS HAVE DEVELOPED ALONG WITH ISOLATED FLURRIES.

18Z SFC ANALYSIS HAS A WARM FRONT FROM THE APPROACHING CLIPPER TYPE
SYSTEM FROM THE CENTRAL DAKOTAS INTO NEBRASKA. SEVERAL WEAK TROFS
RAN FROM THE EASTERN GREAT LAKES INTO THE UPPER MIDWEST. DEW POINTS
WERE MAINLY IN THE SINGLE DIGITS ACROSS THE GREAT LAKES WITH TEENS
ACROSS THE PLAINS.

&&

.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 319 PM CST TUE NOV 18 2014

ISOLATED FLURRIES AND POSSIBLY A SNOW SHOWER WILL CONTINUE ACROSS
THE AREA UNTIL SUNSET AS A WEAK UPPER LEVEL DISTURBANCE MOVES
THROUGH THE AREA.

AFTER SUNSET...SOME PARTIAL CLEARING OF THE CLOUDS SHOULD OCCUR
WHICH WILL ALLOW TEMPERATURES TO DROP. DEVELOPING SOUTHERLY FLOW
AHEAD OF THE NEXT STORM SYSTEM WILL STOP THE TEMPERATURE FALL BY
MIDNIGHT AND ALLOW TEMPERATURES TO SLOWLY START CLIMBING AS A WARM
FRONT MOVES INTO THE AREA.

AFTER MIDNIGHT FORCING FROM THE APPROACHING STORM SYSTEM INCREASES
ALLOWING SATURATION OF THE ATMOSPHERE TO OCCUR. LIGHT SNOW WILL
DEVELOP/MOVE INTO THE AREA WITH AREAS NORTH OF I-80 HAVING A CHANCE
TO SEE SNOW. THE HIGHWAY 20 CORRIDOR HAS THE BEST CHANCES OF SEEING
SOME ACCUMULATING SNOW BY SUNRISE WEDNESDAY...ESPECIALLY EAST OF
MANCHESTER IOWA.

ON WEDNESDAY...THE OVERALL FORCING BEGINS TO WEAKEN AND MOVE OUT OF
THE AREA. LIGHT SNOW SHOULD STILL BE FALLING OVER THE NORTHEAST TO
EAST THIRD OF THE AREA BUT WILL END BY MID MORNING.

AS FOR OVERALL ACCUMULATIONS...THE HIGHWAY 20 CORRIDOR SHOULD SEE A
DUSTING TO POSSIBLY ONE HALF INCH. AREAS EAST OF DUBUQUE IN THE
HIGHWAY 20 CORRIDOR MAY SEE BETWEEN ONE HALF AND ONE INCH. SOUTH OF
HIGHWAY 20 AND DOWN TO I-80...ONLY A TRACE OF ACCUMULATION IS
EXPECTED.

WINDS WILL BE ON THE INCREASE STARTING AROUND MID MORNING AND
CONTINUE INTO THE AFTERNOON. THE STRONG WINDS WILL HELP USHER IN
MORE COLD AIR AND ALLOW TEMPERATURES TO BE STEADY OR SLOWLY FALL
DURING THE AFTERNOON.

.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 319 PM CST TUE NOV 18 2014

MAIN FORECAST CONCERN IN THE LONG TERM FORECAST IS THE WEATHER
SYSTEM THIS WEEKEND.  DISCREPANCIES BETWEEN THE LONG TERM GUIDANCE
STILL EXISTS...HOWEVER IT APPEARS NOW THAT THE SYSTEM WILL MOSTLY
BRING RAIN TO THE AREA.

AT THE BEGINNING OF THE PERIOD NW FLOW WILL CONTINUE TO KEEP US IN
THE COLD AIR. AN EXITING SURFACE LOW WILL LEAD TO GUSTY WINDS ON
THURSDAY AM.  AS THE SURFACE HIGH ADVECTS INTO THE AREA...WINDS WILL
SUBSIDE.  COLD AIR WILL BE FIRMLY IN PLACE ACROSS THE AREA THROUGH
FRIDAY.  THE UPPER FLOW WILL TURN TO A MORE ZONAL PATTERN AND START
TO TURN SW IN FRONT OF A TROUGH FORECAST TO BE OVER THE SOUTHERN
PLAINS.  THIS FLOW WILL HELP TO WARM US UP TO NEAR SEASONAL
TEMPERATURES FOR THE WEEKEND.  MOISTURE WILL OVERRUN THE AREA AS THE
WAA MOVES INTO THE AREA.  THIS COULD LEAD TO THE DEVELOPMENT OF FZRA
OR FZDZ FRIDAY NIGHT.  ANY ICE ACCUMS WOULD BE LIGHT AND WOULD MELT
SATURDAY AS WARMER AIR AND RA MOVES IN. LOW PRESSURE WILL TRACK
ACROSS THE AREA AND LEAD TO A WET WEEKEND.  THIS SYSTEM WILL STAY IN
THE AREA FOR A WHILE AND EXIT EARLY IN THE WEEK NEXT WEEK.  AFTER
THIS SYSTEM MODELS DIVERGE GREATLY.  THE ECMWF LEADS TO ANOTHER COLD
OUTBREAK...THOUGH MORE MODERATED IN THE 12Z RUN FROM THE 00Z
RUN...AND THE 12Z GFS HAS US ZONAL AND WARMER.

AS FAR AS GUIDANCE GOES...GOOD AGREEMENT THROUGH EARLY SATURDAY.  AT
THIS POINT THE GFS IS DEEPER AND SLOWER THAN THE ECMWF. AS A RESULT
THE ECMWF BRINGS THE LOW OVER THE CWA SOONER AND THE GFS IS LATER
AND FURTHER TO THE EAST.  SENSIBLE WEATHER WISE...THERE WILL BE
LITTLE DIFFERENCE TO THE PUBLIC...EXCEPT FOR THE LOCATIONS OF
RAINFALL MAXIMA.  AS FAR AS WHAT MODEL APPEARS TO BE THE MOST
CORRECT.  THE GFS AND GEFS HONE IN ON A SOLUTION.  BOTH AGREE WITH
THE SLOWER LOW AND DEEPER TROUGH.  THIS MEANS CONFIDENCE IN THE GFS
IS HIGHER AS A POTENTIAL FORECAST.  WPC SUGGESTS THAT THE ECMWF AND
GEM ENSEMBLE MEMBERS ARE SLOWER AS WELL.  AT THIS TIME...I WOULD GO
WITH A GFS SOLUTION.  AFTER THE SYSTEM MOVES OUT...IT IS ANYONE
GUESS AS TO WHETHER THE GFS OR ECMWF IS CORRECT.  AS THE COLD AIR
SURGES IN ON MONDAY BEHIND THE SYSTEM IT IS LIKELY THAT THE RAIN
WILL TURN TO SNOW AS THE SYSTEM EXITS THE AREA.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING)
ISSUED AT 526 PM CST TUE NOV 18 2014

MAINLY VFR CONDITIONS WILL BE FOUND THIS EVENING WITH SFC WINDS
AROUND 10 KTS BACKING TO SOUTHERLY. OVERNIGHT...A FAST MOVING
DISTURBANCE AND ATTENDANT SFC WARM FRONT WILL PASS ACCOMPANIED
BY FLURRIES AND AREAS OF LIGHT SNOW. ATTIM... KDBQ HAS BEST CHC
OF LOWERING CONDITIONS INTO MVFR WITH -SN... WITH VFR CONDITIONS
AND FLURRIES ELSEWHERE. THE SNOW SHOULD EXIT BY 12Z. WINDS WILL
SHIFT TO WEST/NORTHWEST EARLY WED AM AND BECOME GUSTY AT 25-30 KTS.
ANTICIPATE LOWER CLOUDS WITH MVFR CIGS TO DEVELOP ACROSS THE
TERMINALS BY MID-LATE WED AM AND AFTN.

&&

.CLIMATE...
ISSUED AT 244 AM CST TUE NOV 18 2014

RECORD LOWS FOR NOVEMBER 18...

MOLINE.........7 IN 1891
CEDAR RAPIDS...5 IN 1891
DUBUQUE........5 IN 1891
BURLINGTON....10 IN 1989

RECORD COOL HIGHS FOR NOVEMBER 18...

MOLINE.........26 IN 1880
DUBUQUE........20 IN 1903

&&

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

$$

SYNOPSIS...08
SHORT TERM...08
LONG TERM...GIBBS
AVIATION...05
CLIMATE...ERVIN






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