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000
FXUS63 KDVN 091303
AFDDVN

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
703 AM CST MON DEC 9 2013

.UPDATE...
ISSUED AT 700 AM CST MON DEC 9 2013

SKIES HAVE CLEARED ACROSS MOST OF THE AREA...ESPECIALLY ACROSS WEST
AND NORTHWESTERN SECTIONS OF THE CWFA. AS A RESULT...TEMPERATURES
HAVE TAKEN A DIVE DUE TO THE FRESH SNOW COVER. AS OF 7 AM...READINGS
RANGE FROM -2F IN INDEPENDENCE...TO THE LOWER TEENS ALONG AND EAST
OF THE MS RIVER. THIS WILL AFFECT MAXES TODAY. ADJUSTED HIGHS
DOWNWARD INTO THE 7 TO 18 DEGREE RANGE...BUT FEEL I MAY NOT HAVE
GONE COLD ENOUGH.

&&

.SYNOPSIS...
ISSUED AT 314 AM CST MON DEC 9 2013

LATEST SURFACE ANALYSIS SHOWS THE LOW PRESSURE SYSTEM THAT BROUGHT
SNOW TO THE AREA SUNDAY...QUICKLY MOVING OFF TO THE NORTHEAST.
LINGERING FLURRIES ARE SEEN ACROSS ROUGHLY THE NORTHEAST HALF OF THE
CWFA...WHICH SHOULD COME TO AN END OVER THE NEXT HOUR OR SO.
CEILINGS AND VISIBILITIES WILL GRADUALLY IMPROVE EARLY THIS MORNING.
AS OF 2 AM...TEMPERATURES ARE IN THE TEENS AND LOW 20S WITH GUSTY
WEST WINDS MAINLY 5 TO 15 MPH...WITH A FEW SITES GUSTING TO 25 MPH.
TEMPS ACROSS THE WESTERN SECTIONS MAY TAKE A GOOD 5-10 DEGREE DROP
IF SKIES CLEAR.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 314 AM CST MON DEC 9 2013

HIGH PRESSURE WILL BUILD INTO THE AREA BEHIND THE DEPARTING
SYSTEM...BRINGING MOSTLY SUNNY...BLUSTERY...AND FRIGID CONDITIONS TO
THE CWFA.  TEMPERATURES WILL BE VERY SLOW TO RISE DUE TO STRONG COLD
AIR ADVECTION AND THE FRESH SNOW COVER. WHEN TEMPS DO RISE...IT WILL
ONLY BE A FEW DEGREES FROM DAYBREAK READINGS.  GUSTY WEST WINDS OF
10 TO 20 MPH WILL INJECT AN ARCTIC AIR MASS INTO THE REGION
TODAY...WITH SOME AREAS SEEING TEMPERATURE HOLD STEADY OR FALL
THROUGH THE DAY...WHILE OTHER LOCATIONS SEE A SLIGHT RISE NEAR
MIDDAY.  DAYTIME HIGHS WILL RANGE FROM THE UPPER SINGLE DIGITS IN
THE NW PART OF THE CWFA...TO UPPER TEENS TO AROUND 20 ALONG AND EAST
OF THE MS RIVER. WIND CHILL VALUES WILL BE IN THE SINGLE DIGITS
ABOVE AND BELOW ZERO FOR MUCH OF THE DAY.

THE HIGH WILL MOVE EAST OF THE AREA OVERNIGHT...WITH A SW RETURN
FLOW DEVELOPING INCREASING TOWARD DAYBREAK TUE.  OTHERWISE MOSTLY
CLEAR CONDITIONS WITH TEMPERATURES DROPPING INTO THE -3 TO 8 ABOVE
RANGE...WITH THE COLDEST READINGS NW...AND /WARMER/ READINGS SE.
WIND CHILL READINGS LATE TONIGHT AND EARLY TUESDAY WILL BE WELL
BELOW ZERO...ESPECIALLY ACROSS AREAS NORTH OF I 80 WHERE THEY SLIP
INTO THE -10 TO -20 RANGE.

.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 314 AM CST MON DEC 9 2013

PARADE OF CLIPPER SYSTEMS IN THE NW FLOW WILL PRESENT PERIODIC
CHANCES FOR LIGHT SNOW OR FLURRIES OVER THE REGION THROUGH LATE
WEEK. OTHERWISE...WELL BELOW NORMAL TEMPERATURES AND BITTER COLD
WIND CHILLS WILL BE THE MAIN STORY. A MINOR WARMING TREND IS STILL
ON TRACK FOR LATE IN THE WEEK. BEYOND...FORECAST CONFIDENCE REMAINS
LOW DUE TO THE DIFFERENT HANDLING OF MAJOR SURFACE AND UPPER LEVEL
FEATURES IN THE PERIOD OF SPLIT FLOW SHOWN IN MEDIUM RANGE MODELS
OVER THE WEEKEND.

TUESDAY...A CLIPPER PASSING THROUGH WI INTO THE GREAT LAKES IN THE
MORNING COULD RESULT IN A FEW FLURRIES IN THE FAR NORTHEAST EARLY.
OTHERWISE...A TIGHT PRESSURE GRADIENT AND PERIOD OF COLD AIR
ADVECTION FOLLOWING THE FROPA WILL RESULT IN BRISK NW WINDS THROUGH
MOST OF THE DAY. THE DEEP MIXING INTO THE TIGHT N TO S THERMAL
GRADIENT ALOFT...WILL BE ENHANCED BY DEEPER SNOW COVER IN THE
NORTH...TO PRODUCE A LARGER THAN USUAL RANGE OF HIGHS...GOING FROM
THE TEENS NORTH TO MID AND UPPER 20S SOUTH. 15 TO 25 MPH WEST WINDS
WILL KEEP WIND CHILLS WELL BELOW ZERO OVER ESPECIALLY THE
NORTH...WITH SUBZERO TEENS POSSIBLE IN THE MORNING.

MEASURABLE SNOWFALL IS NOW LOOKING LIKELY FOR LATE TUESDAY NIGHT
INTO WEDNESDAY. THERE IS GOOD CONTINUITY AND AGREEMENT IN RECENT
MODELS SUGGESTING THE NEXT CLIPPER SYSTEM WILL TRACK THROUGH THE
FORECAST AREA AND HAVE BUMPED UP POPS TO LIKELY ACROSS THE NORTH FOR
LATE TUE NIGHT. MOISTURE WILL BE LIMITED...BUT EVEN WITH A FEW
HUNDREDTHS UP TO A TENTH INCH OF QPF...THE HIGH LIQUID TO SNOW
RATIOS DUE TO THE COLD AIRMASS WILL BE CAPABLE OF SNOWFALL AMOUNTS
OF AN INCH OR TWO...ESPECIALLY NORTH OF I-80.

THIS SYSTEM RAPIDLY EXITS TO THE EAST BY MIDDAY WEDNESDAY AND THE
REINFORCING SHOT OF COLD AIR THAT FOLLOWS HAS TEMPERATURES
APPROACHING -20 AT 850 MB ALONG THE NORTHERN IA BORDER. THIS MAY
LIMIT THE NORTHWEST TO NO WARMER THAN THE SINGLE DIGITS WITH TEENS
TO LOWER 20S FURTHER SOUTH AND EAST. WHILE WINDS NOT WILL NOT BE AS
STRONG AS TUESDAY...WIND CHILLS WILL STILL BE BITTER COLD IN THE
SINGLE DIGITS BELOW ZERO THROUGH MUCH OF THE DAY. IF WINDS DECOUPLE
AND SKIES CLEAR OUT UNDER THE TRANSITORY RIDGE THAT FOLLOWS WED
NIGHT...WIDESPREAD MINS BELOW ZERO LOOK LIKELY AND THE CURRENT RANGE
FROM AROUND -4 NORTH TO PLUS 4 SOUTH MAY NEED TO BE REVISED DOWNWARD
IF THIS SETUP IS MAINTAINED.

THURSDAY AND FRIDAY LOOK PROGRESSIVELY WARMER WITH ANY WEAK CLIPPER
SYSTEMS TRACKING WELL TO THE NORTH. HIGHS COULD BREAK THE FREEZING
MARK AND POSSIBLY REACH THE MID 30S IN THE SOUTH BY FRIDAY
AFTERNOON. A DEVELOPING SOUTHERN STREAM SHORTWAVE MAY BRING SNOW
INTO ESPECIALLY THE SOUTH FRIDAY NIGHT INTO EARLY SATURDAY AND THESE
CHANCES ARE CONTINUED IN THE FORECAST. BEYOND...THE ECMWF IS MORE
AGGRESSIVE WITH A MORE SOUTHERLY TRACKING SYSTEM IN THE NORTHERN
STREAM THAT COULD BRING SNOW INTO THE NORTH SATURDAY NIGHT INTO
SUNDAY...WHERE THE GFS MAINTAINS A SURFACE RIDGE AND DRY WEATHER.
FOR NOW...A LOW CONFIDENCE...DRY FORECAST IS KEPT FOR SATURDAY INTO
SUNDAY WITH TEMPERATURES TRENDED CLOSER TO CLIMO.

IF THE LATEST ECMWF WERE TO HOLD TRUE WITH ITS STRONG ARCTIC COLD
FRONT FOLLOWING THE SUNDAY SYSTEM...TEMPERATURES COULD PLUNGE INTO
THE TEENS BELOW ZERO BY MONDAY MORNING. HOWEVER...THIS TREND IS A
RECENT MODEL DEVELOPMENT IN A PERIOD THAT HAS HAD POOR RUN TO RUN
CONTINUITY AND WILL LIKELY TO HAVE A DIFFERENT LOOK ALTOGETHER IN
NEWER MODEL RUNS. THE OVERALL PATTERN...HOWEVER...SUGGESTS A RETURN
TO AN ACTIVE NW FLOW AND NEAR TO BELOW NORMAL TEMPERATURES FOR THE
FIRST PART OF NEXT WEEK.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 532 AM CST MON DEC 9 2013

SOME LINGERING LIGHT SNOW AND LOW CLOUDS AT 1-3K FT WILL QUICKLY
EXIT THE AREA THIS MORNING...LEAVING VFR CIGS...IF ANY...FOR THE
REMAINDER OF THE TAF PERIOD. WEST WINDS AT ABOUT 15-20 MPH WILL
PREVAIL FOR MUCH OF THE DAY...GUSTING BETWEEN 20-30 MPH DURING THE
LATE MORNING AND AFTERNOON. THEY WILL SUBSIDE TO UNDER 10 MPH THIS
EVENING...BEFORE BACKING TO THE SOUTH SOUTHWEST AND INCREASING
AFTER 06Z.


&&

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

$$

UPDATE...14
SYNOPSIS...14
SHORT TERM...14
LONG TERM...SHEETS
AVIATION...14