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000
FXUS63 KDVN 060550
AFDDVN

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
1150 PM CST THU DEC 5 2013

.SYNOPSIS...
ISSUED AT 318 PM CST THU DEC 5 2013

THE LATEST SFC ANALYSIS WAS INDICATING LARGE CANADIAN RIDGE AXIS
DRAPED FROM MT...DOWN INTO THE SOUTHEASTERN PLAINS AND LOWER MS RVR
VALLEY. THIS TO THE WEST OF LINGERING CYCLONIC PRESSURE GRADIENT
ACRS THE UPPER MS RVR VALLEY AND WESTERN GRT LKS AS OCCLUDED SFC LOW
COMPLEX SPIRALS JUST WEST OF JAMES BAY. VIS SATELLITE LOOP INDICATING
ESTABLISHED SNOW FIELDS ACRS MT...THE DAKOTAS...NORTHERN NEB...MN AND
NW WI. COLD LLVL NORTHWEST FETCH OFF THESE SNOW AREAS AND DOWN ACRS
IA. ALOFT...12Z UPPER AIR ANALYSIS AND MID/UPPER LEVEL MOISTURE FLOW
PATTERNS ON WATER VAPOR IMAGERY LOOP WAS SHOWING DEEP L/W TROF ACRS
MUCH OF THE WESTERN CONUS PIVOTING ACRS THE NORTHERN BAJA...WHILE
NEARLY STACKED UPPER LOW WAS ROLLING NORTHEASTWARD JUST WEST OF JAMES
BAY. THE W/V LOOP ALSO SHOWING LARGE SCALE/LONG FETCH MOISTURE FEED
FROM WELL WEST OF THE BAJA CA....UP ACRS MUCH OF THE SOUTHEASTERN
HALF OF THE CONUS.

&&

.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 318 PM CST THU DEC 5 2013

TONIGHT...ALTHOUGH THE NORTHWESTERLY SFC WINDS WILL DECREASE TO
AROUND 10 TO 12 MPH OVERNIGHT...COLD AIR ADVECTION MACHINE STILL IN
FULL GEAR FROM NORTHERN PLAINS SOURCE REGION. STILL EXPECT ROUNDS
OF VARYING THICKNESS CIRRUS AND POSSIBLY SOME HIGHER BASED AC OFF
OVERRUNNING WINTER STORM SYSTEM ONGOING ACRS THE SOUTHERN PLAINS AND
UP THE OH RVR VALLEY. THUS MOSTLY CLOUDY TONIGHT...LITTLE OR NO
SNOW COVER...AND MIXING WINDS OF 10+ MPH WILL KEEP TEMPS FROM
BOTTOMING OUT TO SUBZERO READINGS. BUT STILL A COLD NIGHT IN STORE
WITH LOWS IN THE LOWER SINGLE DIGITS ABOVE ZERO IN THE FAR WEST AND
NORTHWEST...5-10 ABOVE TO THE MS RVR...AND LOWER TO MID TEENS EAST
OF THE MS RVR. THESE TEMPS COMBINED WITH THE WINDS TO PRODUCE WIND
CHILLS FROM ZERO..TO 10-12 BELOW ZERO WEST OF THE MS RVR LATE
TONIGHT AND THROUGH 6 AM CST FRI AM. WILL KEEP THE FCST DRY FOR
NOW...BUT EXTRAPOLATING SOME OF THE ELEVATED SNOW BANDS IN SOUTH
CENTRAL KS NORTHEASTWARD...SOME CHC THAT THEY MAY CLIP THE FAR
SOUTHERN CWA OVERNIGHT. BUT IF THEY DO...WILL BANK ON DRIER LLVLS
TO LIMIT THEM TO FLURRIES.

FRIDAY...ANOTHER COLD DAY CHARACTERIZED BY FILTERED SUNSHINE BY
OVERRUNNING CLOUDS OFF STORM SYSTEM JUST OFF TO THE SOUTHEAST.
MOSTLY CLOUDY CONDITIONS AND NORTHWEST WINDS OF 10-20 MPH IN
LINGERING RIDGE PRESSURE GRADIENT AS IT TRIES TO MAKE HEADWAY AND
SLIDE THIS WAY. AGAIN...WILL KEEP THE FCST DRY BUT WOULD NOT BE
SURPRISED IF SOME OVERRUNNING FLURRIES OR EVEN LIGHT SNOW
OCCASIONALLY CLIP THE FAR SOUTHERN AND SOUTHEASTERN CWA FROM TIME
TO TIME. CLOUD COVER AND CONTINUED CAA TO LIMIT HIGH TEMP RECOVERY
TO THE MID TEENS IN THE NORTHWEST...TO THE UPPER TEENS OR AROUND 20
DEGREES ALONG AND EAST OF THE MS RVR.    ..12..

.LONG TERM...(FRIDAY NIGHT THROUGH NEXT THURSDAY)
ISSUED AT 318 PM CST THU DEC 5 2013

THE COLD WEATHER LOOKS LIKE IT WILL BE LOCKED IN OVER THE REGION
THROUGH MUCH OF NEXT WEEK WITH THE MODELS KEEPING A PERSISTENT BROAD
H5 TROF OVER THE CENTRAL AND WESTERN U.S.

DRY AND COLD CONDITIONS ARE EXPECTED SATURDAY AS HIGH PRESSURE MOVES
EAST ACROSS NORTHERN IA AND SOUTHERN MN.  LOW TEMPERATURES IN THE
SINGLE DIGITS LOOK REASONABLE WITH LIGHT WINDS IN THE WEAK GRADIENT
NEAR THE HIGH AND CLEAR SKIES.  LITTLE MIXING DURING THE DAY SUPPORT
TEENS AND LOW 20S FOR HIGHS.

A S/W MOVING OUT OF SOUTHWESTERN U.S. TROF AXIS WILL SPREAD MID
CLOUDS OVER THE AREA SUNDAY NIGHT.  A FLURRY CAN/T BE RULED OUT WEST
OF THE RIVER AFTER MIDNIGHT WITH A BROAD REGION OF ISENTROPIC LIFT
AND MOISTENING MID LEVELS AHEAD OF THE S/W.  HOWEVER...LOW LEVELS
REMAIN DRY WHICH SHOULD PREVENT ANY MEASURABLE SNOW.  THE INCREASING
CLOUD COVER SATURDAY NIGHT WILL KEEP TEMPERATURES FROM FALLING MUCH
WITH LOWS AROUND 10 EXPECTED.

ACCUMULATING SNOW IS EXPECTED SUNDAY AND SUNDAY NIGHT AS THE S/W
MOVES THROUGH THE REGION.  THE GFS/ECM HAVE BEEN VERY CONSISTENT
PAINTING A BROAD AREA OF QPF OVER THE REGION WITH THIS S/W WITH
WATER EQUIVALENTS UP TO TWO TENTHS OF AN INCH.  THE ECMWF HAS ALSO
BEEN CONSISTENT IN KEEPING THE HIGHER AMOUNTS OVER THE NORTHERN CWFA
WHICH LOOKS REASONABLE BASED ON THE THE TRACK OF THE VORT THROUGH
NORTHERN MO/ SOUTHERN IA. TEMPERATURES WILL BE COLD ENOUGH FOR SOME
HIGH SNOW TO LIQUID RATIOS...POSSIBLY UP TO 20 TO 1 OVER THE
NORTHERN CWFA. FOR NOW A CONSERVATIVE 17 TO 1 RATIO WAS USED WHICH
PRODUCED 24 HOUR SNOWFALL AMOUNTS OF 2 TO NEARLY 4 INCHES OVER THE
NORTHWEST HALF OF THE AREA BETWEEN 12Z SUNDAY AND 12Z MONDAY.
FORECAST SNOW AMOUNTS OVER THE SOUTHEAST HALF WERE IN THE 1 TO 2
INCH RANGE.  WIND DURING THE EVENT SHOULD STAY AROUND 10KTS OR LESS
SO NO SIGNIFICANT BLOWING OR DRIFTING IS EXPECTED. THE SNOW SHOULD BE
EAST OF THE AREA BY MONDAY MORNING.

ANOTHER SHOT OF VERY COLD AIR IS PULLED SOUTH INTO THE REGION BEHIND
SUNDAYS SYSTEM.  H8 TEMPS ARE PROGGED TO DIP TO -15 TO -20C BY
TUESDAY NIGHT. HIGHS NEXT WEEK SHOULD BE IN THE TEENS AND 20S WITH
LOWS MAINLY IN THE SINGLE DIGITS AND TEENS.  THE ECM CONTINUES TO
SHOW A STRONG HIGH PRESSURE SYSTEM OVER THE REGION BY MID WEEK WITH
THIS MORNINGS 12Z RUN INCREASING THE PRESSURE TO 1045MB. IF THIS
VERIFIES AND THERE IS SNOW COVER THEN WE COULD SEE LOW TEMPERATURES
SIGNIFICANTLY COLDER THAN CURRENTLY FORECAST FOR THE MIDDLE OF THE
WEEK. THE GFS ON THE OTHER HAND CONTINUES TO SUGGEST ONE OR TWO WEEK
CLIPPER SYSTEM MOVING THROUGH WHICH WOULD ARGUE AGAINST EXTREMELY
COLD TEMPERATURES.    DLF

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1138 PM CST THU DEC 5 2013

PATCHY LOW CLOUDS WITH AN OCCASIONAL MVFR CIG ARE CURRENTLY BEING
FOUND OVER NORTHEAST IOWA. LATEST RAP MODEL OUTLIER WITH
INCREASING THE LOW CLOUDS AND ADVECTING SOUTHEAST OVER MUCH OF
AREA ESPECIALLY NORTH OF I-80 OVERNIGHT AND FRIDAY MORNING.
WHILE SOME PRESENCE OF LOW LEVEL THETA-E AXIS AND LOW LEVEL
FRONTOGENESIS COULD FOSTER ADDITIONAL LOW CLOUDS NOT VERY CONFIDENT
TO MENTION ANY CIGS... BUT DID MAINTAIN SCATTERED CLOUD BASES
AROUND 2KFT AGL ONLY AT KDBQ FOR NOW BEING CLOSER TO THE ABOVE
MENTIONED FEATURES. OTHERWISE...VFR CONDITIONS WITH MID/HIGH
CLOUDINESS FROM STORM SYSTEM PASSING TO OUR SOUTH ON FRIDAY. WINDS
WILL REMAIN GENERALLY NORTHWEST AROUND 10-15 KTS WITH SOME LOCALLY
HIGHER GUSTS POSSIBLE AT TIMES.

&&

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

$$

SYNOPSIS...12
SHORT TERM...12
LONG TERM...DLF
AVIATION...05