Area Forecast Discussion
Issued by NWS Quad Cities, IA IL

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000
FXUS63 KDVN 270347
AFDDVN

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
947 PM CST FRI DEC 26 2014

.UPDATE...
ISSUED AT 940 PM CST FRI DEC 26 2014

VERY LIGHT PCPN EVENT UNDERWAY WITH RADAR RETURNS BLOSSOMING
WEST/SOUTHWEST OF QUAD CITIES AND A FEW OBS REPORTING SPRINKLES OR
PATCHY VERY LIGHT RAIN. THIS IS OCCURRING WITH SURGE OF ISENTROPIC
LIFT AND CONVERGENCE ALONG FRONT AIDED BY APPROACHING WEAK SURFACE
LOW. OUR CWA FOR THIS EVENT WILL LARGELY REMAIN IN BETWEEN
STRONGER FORCING TO OUR W/NW LIFTING FROM THE PLAINS INTO THE
UPPER MIDWEST... AND DEEPER MOISTURE PLUME (PWATS APPROACHING 1
INCH) VEERING FROM MO THROUGH CENTRAL IL. AS RESULT EXPECTING VERY
LIGHT RAIN AMOUNTS WHERE IT DOES OCCUR AND GENERALLY FROM TRACE TO
LESS THAN 0.1 INCH. STILL HAVE CHANCE OF RAIN MIXED WITH SNOW LATE
TONIGHT INTO SATURDAY MORNING NORTHWEST CWA... BUT SOME OF THE
LATEST MODEL SOUNDINGS SHOWING CONSIDERABLE DRYING IN MID LEVELS
AND THUS WOULD SUGGEST MORE LIKELY JUST A FEW FLURRIES OR POSSIBLY
PATCHY DZ/FZDZ DEPENDING ON MOISTURE DEPTH AND ICE INTRODUCTION.
AS RESULT...HAVE CONTINUED TO TRIM ANY SNOW ACCUMS NORTHWEST CWA.

AS FOR TEMPS... WILL CONTINUE TO SEE DECENT GRADIENT ACROSS CWA
WITH COLDEST READINGS (30-35F) WEST/NORTHWEST NEAR AND JUST ON
COLD SIDE OF FRONT. MEANWHILE MANY AREAS ALONG AND EAST OF THE
MISSISSIPPI RIVER WILL REMAIN IN THE 40S REST OF TONIGHT. TEMPS WILL
EVEN RISE A FEW MORE DEGS TO AROUND 50 OR LOWER 50S FOR A TIME LATE
THIS EVE INTO EARLY OVERNIGHT FROM QUAD CITIES S/E.

UPDATED GRIDS/ZFP/PFM HAVE BEEN SENT.

&&

.SYNOPSIS...
ISSUED AT 215 PM CST FRI DEC 26 2014

ANOTHER MILD LATE DECEMBER DAY WITH FILTERED SUNSHINE THROUGH CIRRUS
CLOUDS STREAMING NORTHEAST ACROSS THE CWA. 2 PM TEMPERATURES RANGED
FROM THE MID 40S FAR NORTH TO THE MID 50S FAR SOUTH.

A NEARLY STATIONARY STRONG FRONTAL BOUNDARY EXTENDED FROM CENTRAL WI
TO CENTRAL IA AND THEN INTO THE TX PANHANDLE. TEMPERATURES AHEAD OF
THE FRONT WERE MAINLY IN THE 50S WHILE BEHIND THE FRONT READINGS WERE
ONLY IN THE 20S TO LOWER 30S. A BAND OF SNOW EXTENDED FROM EASTERN
CO/WESTERN KS NORTHEAST INTO CENTRAL/WESTERN NEB.

&&

.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 215 PM CST FRI DEC 26 2014

FORECAST FOCUS ON MAINLY LIGHT RAIN TONIGHT THEN OUR RECENT STRETCH
OF MILD WEATHER COMES TO A SCREECHING HALT ON SATURDAY.

TONIGHT...OPERATIONAL MODELS SIMILAR IN TRACKING A WEAK LOW PRESSURE
SYSTEM FROM THE SOUTHERN PLAINS INTO EASTERN IOWA BY SUNRISE. THIS
PUTS THE ACCUMULATING SNOW TO THE NW OF THE DVN CWA WHERE THE COLDER
AIR AND BETTER FORCING WILL EXIST. MODELS ALSO SIMILAR IN KEEPING
THE DEEPER MOISTURE TO OUR SE WITH ONLY LIGHT RAIN AMOUNTS EXPECTED
IN THE DVN CWA...ABOUT A TENTH OF AN INCH OR LESS. THE HIGHER POPS
WILL BE POST-FRONTAL AS THE COLD FRONT MAKES SLOW PROGRESS INTO
EASTERN IA OVERNIGHT. AHEAD OF THE FRONT SCATTERED SHOWERS SHOULD
DEVELOP ESPECIALLY AFTER MIDNIGHT. FORECAST SOUNDINGS INDICATE THE
COLUMN COOLS BELOW FREEZING IN OUR FAR NW CWA TOWARDS MORNING BUT
BY THAT TIME MOISTURE IS DECREASING. SO WILL CONTINUE TO MENTION A
RAIN/SNOW MIX LATE TONIGHT THEN TURNING TO ALL SNOW BUT IF ANY ACCUMULATIONS
OCCUR IT WOULD BE A DUSTING ON GRASSY SURFACES. ANOTHER MILD NIGHT
WITH MINIMUM TEMPERATURES RANGING FROM THE LOWER 30S AT INDEPENDENCE
IA TO THE MID 40S AT MACOMB IL.

SATURDAY...DEEPENING LOW PRESSURE TRACKS TO EASTERN UPPER MI BY LATE
IN THE AFTERNOON. FORCING ALONG WITH 1000-500 MB MEAN RH QUICKLY DECREASES
IN THE MORNING THUS WILL FOLLOW SUIT WITH DECREASING POPS. THE COLD
FRONT WILL SWEEP THROUGH THE REMAINDER OF THE CWA DURING THE MORNING
WITH COLDER/DRIER AIR FILTERING INTO THE CWA BEHIND THE FRONT...SO HAVE
REMOVED POPS FOR THE AFTERNOON. ALSO DURING THE AFTERNOON WE WILL BE
COLD ADVECTING AND WITH CYCLONIC FLOW THIS WILL KEEP LOW CLOUDS IN PLACE...
ALONG WITH THE DREADED FALLING TEMPERATURES. HIGHS ON SATURDAY WILL
ACTUALLY OCCUR IN THE MORNING...RANGING FROM THE LOWER 30S NW TO THE
MID 40S IN OUR FAR EASTERN COUNTIES.

.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 215 PM CST FRI DEC 26 2014

MAIN FORECAST CONCERN FOR THE EXTENDED FORECAST ARE THE TEMPERATURES
AND TWO SYSTEMS FORECAST TO MOVE THROUGH THE AREA. ONE SYSTEM ON
MONDAY INTO TUESDAY LOOKS LIKE THERE IS A CHANCE FOR LIGHT SNOW WITH
LITTLE TO NO ACCUMULATION. THE ONE AT THE END OF THE PERIOD LOOKS TO
HAVE A BETTER CHANCE OF PRECIPITATION...HOWEVER THE ARE DISCREPANCIES
IN THE MODELS LEADING TO DIFFERENCES IN TIMING.

AT THE BEGINNING OF THE PERIOD A WAVE IS EXPECTED TO BE EXITING
THE AREA AND CLOUD COVER LOOKS TO BE DECREASING OVERNIGHT. WHILE
TEMPERATURES MAY NOT BE THAT WARM ON SUNDAY...WE WILL SEE SUN
NONETHELESS...MAKING FOR A PLEASANT SUNDAY. A WEAKENING WAVE IS
FORECAST TO ADVECT INTO THE AREA MONDAY AND LEAD TO SOME SLIGHT
CHANCES OF SNOW MONDAY. NOT IMPRESSED AT ALL WITH THIS SYSTEM...THINK
THAT OVERALL SNOWFALL WILL BE LIGHT AND MOST LIKELY TO OCCUR IN
WESTERN AND NORTHERN ZONES. IF IT DOES SNOW...IT WILL LIKELY BE OF
THE NUISANCE VARIETY.

BEHIND THIS SYSTEM WE SEE OUR COLD TEMPERATURES RETURN TO THE AREA
AGAIN AFTER A WARMER DECEMBER. MONDAY NIGHT AND TUESDAY NIGHT LOOK
TO BE COLD WITH LOWS IN THE SINGLE DIGITS AND EVEN BELOW 0 ON MONDAY.
WIND CHILLS WILL BE BELOW 0 ON MONDAY NIGHT...CLOSE TO TEN BELOW
IN NW ZONES AND THEN -15 ON TUESDAY NIGHT IN NW ZONES. AFTER THIS
THE FLOW BEGINS TO MODERATE AND TEMPERATURES WARM BACK UP TO NEAR
NORMAL.

AT THE END OF THE PERIOD ANOTHER SYSTEM IS FORECAST TO AFFECT THE
MIDWEST. IT IS TOO EARLY TO NAIL DOWN SPECIFICS OF THIS STORM.
CURRENT FORECAST SUGGESTS THAT THE FREEZING LINE WILL BE OVER THE
CWA...MEANING WE COULD SEE A RASN MIX WITH IT. THIS WILL PROBABLY
CHANGE AS WE GET CLOSER TO THE FORECAST.

AS FAR AS TEMPERATURE FORECASTS GO...LONG TERM BOI VERIFY STATS
SUGGEST THAT THE CONSRAW BLEND IS NAILING THE TEMPERATURES FOR
HIGHS AND LOW IN THE 30 TO 45 DAY AVERAGE. DECIDED TO START WITH
THESE TEMPS AND THEN ADJUST THEM A DEGREE OR TWO FROM THERE.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 554 PM CST FRI DEC 26 2014

VFR CONDITIONS ARE EXPECTED TO LINGER FOR MUCH OF THIS EVENING.
CONDITIONS THEN TO DETERIORATE TO MVFR AND IFR IN LOW CLOUDS WITH
AREAS OF LIGHT RAIN OVERNIGHT INTO EARLY SATURDAY MORNING...AS LOW
PRESSURE MOVES ALONG STALLED FRONT INTO EASTERN IA. THERE IS
A CHANCE THE LIGHT RAIN MAY MIX WITH LIGHT SNOW AT CID AND DBQ
BEFORE ENDING. CLOUDY SKIES EXPECTED FOR MOST OF SATURDAY WITH
IFR CIGS GRADUALLY LIFTING TO MVFR. WINDS LIGHT AND VARIABLE TONIGHT
BECOMING WESTERLY AOA 10 KTS SATURDAY WITH GUSTS AROUND 20 TO 25 KTS
AT TIMES.


&&

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

$$

UPDATE...05
SYNOPSIS...HAASE
SHORT TERM...HAASE
LONG TERM...GIBBS
AVIATION...05




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