National Weather Service National Headquarters

• Home
• Site Map
• News
• Organization
• Search for: NWS All NOAA 

000
FXUS63 KDVN 040005
AFDDVN

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
605 PM CST TUE DEC 3 2013

.SYNOPSIS...
ISSUED AT 340 PM CST TUE DEC 3 2013

WARM FRONT REACHING FROM DEVELOPING LOW OVER SE CO REACHED E-NE
ACROSS CENTRAL KS TO S CENTRAL IA TO N CENTRAL IL THIS AFTERNOON. AT
21Z...SURFACE ANALYSIS AND VISIBLE SATELLITE IMAGERY INDICATED THE
BOUNDARY BETWEEN FAIRFIELD AND WASHINGTON SE TO BETWEEN GALESBURG AND
MACOMB. FOG WAS WIDESPREAD NORTH OF THIS BOUNDARY AND HAS REMAINED
DENSE THROUGH THE DAY ALONG THE HIGHWAY 20 CORRIDOR. SOUTH OF THE
BOUNDARY...TEMPERATURES WERE IN THE 50S...WHILE 40S WERE FOUND TO
THE NORTH. THE PRIMARY PUSH OF ARCTIC AIR WAS STILL IN THE
PLAINS...WHERE THE MAIN COLD FRONT REACHED FROM NW MN S-SW TO THE
NEB PANHANDLE. BEHIND THIS BOUNDARY...TEMPERATURES WERE IN THE TEENS
AND 20S.

&&

.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 340 PM CST TUE DEC 3 2013

THE REBOUND OF WIDESPREAD DENSE FOG IS THE INITIAL CHALLENGE...THEN
TRENDS WITH THE PASSAGE OF THE STRONG COLD FRONT THAT IS NOW LIKELY
TO PUSH THROUGH WED AFTERNOON.

THE WARM FRONT WILL TRY TO PUSH NORTH TONIGHT AS THE CO LEE LOW
MIGRATES NORTHEAST ALONG THE BOUNDARY IN KS. THE BROAD LOW LEVEL
CONVERGENT FLOW AND MOISTURE ADVECTION AS DEWPOINTS IN THE 40S OVER
MO AND IL ARE DRAWN NORTH AND NORTHWESTWARD WILL KEEP THE LOW LEVELS
SATURATED. THE HRRR AND SREF FOG PROG TOOLS ARE IN ALIGNMENT WITH
THE CURRENT AREA OF DENSE FOG AND HAVE THIS EXPANDING BACK SOUTH AND
SOUTHWEST OVERNIGHT. THIS IS ALONG THE AREA OF CURRENT CONVERGENCE
FROM S CENTRAL IA NE TO NW IL AND HAVE EXPANDED OUR DENSE FOG
ADVISORY TO COVER THESE AREAS OVERNIGHT. HAVE THIS GOING UNTIL NOON
WEDNESDAY...WHEN THE ENHANCED MIXING AHEAD OF THE FRONT SHOULD BRING
SOME IMPROVEMENT. ACROSS FAR SOUTHEAST IA...FAR NE MO AND WEST
CENTRAL IL ALONG THE I-80 CORRIDOR...FOG WILL LIKELY RETURN...BUT
THERE IS LOW CONFIDENCE AS TO WHETHER IT WILL BECOME DENSE. HAVE
THUS HELD OFF ON AN ADVISORY...BUT WILL NEED TO MONITOR CLOSELY.
OTHERWISE...THE DEVELOPING LIFT AND INCREASING DIFLUENCE IN FLOW
ALOFT WILL SUPPORT ANOTHER ROUND OF LIGHT RAIN...ESPECIALLY TOWARD
MORNING ACROSS THE NORTH AND HAVE MAINTAINED CHANCE POPS.
ELSEWHERE...WILL KEEP A MENTION OF DRIZZLE WITH THE FOG.

WEDNESDAY...LATEST MODELS CONTINUE TO TREND TOWARD THE
EARLIER...SLOWER ECMWF RUNS WITH THE TIMING OF THE FROPA. THE
GFS...NAM...ECMWF...AND GEM OFFER SIMILAR SOLUTIONS WITH THE WAVE OF
LOW PRESSURE MOVING OUT OF THE PLAINS...LIFTING THROUGH THE FORECAST
AREA WEDNESDAY AFTERNOON. THIS USHERS THE PRIMARY COLD FRONT THROUGH
THE AREA BY EARLY EVENING. HAVE TRENDED THE FORECAST TOWARD THE
SLIGHTLY SLOWER ECMWF AND CANADIAN SOLUTIONS...KEEPING THE
PRECIPITATION IN THE FORM OF RAIN WITH A POSSIBLY RAIN/SNOW MIX IN
THE FAR NW LATE. WITH THE PRIMARY WARM SECTOR SWEEPING THROUGH THE
MUCH OF THE WARM SECTOR...WE SHOULD TAP INTO THE AIRMASS OVER
EASTERN MO AND SOUTHERN IL RESULTING IN MORNING OR EARLY AFTERNOON
HIGHS FROM THE LOWER 40S NW TO NEAR 60 IN THE FAR SE.

.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 340 PM CST TUE DEC 3 2013

WEDNESDAY NIGHT THROUGH FRIDAY...TAKING INTO ACCOUNT A TYPE OF
ENSEMBLE FRONTAL MOVEMENT OF THE 12Z MODEL RUNS AND EVEN SLOWING
THAT DOWN SOME AS DEEPENING CYCLONE WRAPS UP SOMEWHERE ACRS
SOUTHWEST INTO CENTRAL WI WED EVENING...IT SHOULD BE PUSHING EAST OF
THE DVN CWA BY 01Z-02Z THU. CONVERGENT FORCING OFF THIS PROCESS MAY
WRING OUT SOME LIGHT RAIN OR DRIZZLE ALONG AND EAST OF THE MS RVR THE
FIRST 1-2 HRS OF THE FCST PERIOD. BUT THE MAIN OVERNIGHT WX STORY
WILL BE THE INCREASING WESTERLY POST-FRONTAL SFC WINDS AND DEVELOPING
LLVL COLD CONVEYOR IN-WRAPPING FROM THE NORTHWEST. BRISK WEST WINDS
OF 15 TO 25+ MPH SHOULD COLD AIR ADVECT TEMPS INTO THE UPPER TEENS
IN THE NORTHWEST...TO THE MID 20S IN THE EAST BY THU MORNING. THE
12Z RUNS THEN SUGGEST THAT AS 1035-1040 MB HIGH DUMPS DOWN THE
NORTHWESTERN PLAINS AND TIGHT CYCLONIC GRADIENT LINGERS SOME OFF
NORTHERN GRT LKS DEEP LOW PRESSURE CENTER...WINDY CONDITIONS TO
CONTINUE THROUGH AT LEAST MIDDAY THU WITH AMBIENT TEMPS ONLY
RECOVERING 3-5 DEGREES FROM MORNING VALUES AT 12Z THU. SINGLE DIGIT
ABOVE ZERO WIND CHILLS IN THE NORTHWESTERN HALF OF THE CWA THU AM.
THE ARCTIC FRONT SURGES SOUTH AND PRODUCES TIGHTENING LLVL
BAROCLINICITY AS IT SLOWS UNDER SOUTHWESTERLIES ACRS THE DEEP
SOUTHERN PLAINS TO SOUTHEASTERN OH RVR VALLEY. ALONG AND NORTH OF
THIS THERMAL RIBBON TO BE AN AXIS FOR WINTER STORM/ICE CONDITIONS
INTO FRI AND THERE IS STILL SOME VARIANCE BETWEEN THE LATEST RUN
SOLUTIONS OF FRONTAL PLACEMENT AND STRENGTH OF A WAVE RIPPLING UP
ALONG THIS HIGHWAY. THE MAJORITY OF THE 12Z MODEL RUNS STILL KEEP
ANY OVERRUNNING SNOW OFF TO THE SOUTHEAST OF THE CWA THU THROUGH FRI
WITH JUST A MID AND HIGH LEVEL CLOUD DECK MOVING UP ACRS PORTIONS OF
THE CWA LATE IN THE DAY AND OVERNIGHT. BUT THE 12Z RUN NAM AND GEM
ARE MORE BULLISH AND FURTHER NORTH WITH THE OVERRUNNING PRECIP
SHIELD AND CLIP AT LEAST THE SOUTHEASTERN THIRD OF THE DVN CWA WITH
LIGHT SNOW THU NIGHT INTO FRI MORNING. FOR NOW WILL MAINTAIN SLIGHT
CHC POPS ACRS THE FAR SOUTH AND SOUTHEASTERN CORNER OF THE FCST
AREA. MOSTLY CLOUDY...BLUSTERY AND COLD CONDITIONS CONTINUE ON FRI
WITH HIGHS ONLY IN THE UPPER TEENS TO LOWER 20S. THE INCOMING SFC
RIDGE WILL LOOK TO UNFOLD ACRS THE UPPER MS RVR VALLEY FRI NIGHT FOR
CLEARING...SFC WIND DECREASING AND COLD CONDITIONS. MANY LOWS IN THE
SINGLE DIGITS WITH A ZERO EVEN POSSIBLE IN THE NORTHWEST.

SATURDAY AND SUNDAY...THE SFC RIDGE MAINTAINS LOCALLY LONG ENOUGH FOR
A FAIR WX BUT COLD DAY SAT WITH HIGHS IN THE TEENS TO AROUND 20 AS
L/W TROF LOOMS ACRS THE SOUTHWESTERN CONUS/GRT BSN. THE MEDIUM RANGE
SOLUTIONS THEN SUGGEST NORTHERN STREAM UPPER JET ENERGY/TROFFINESS
ACRS WESTERN INTO CENTRAL CANADA TO TRY AND PHASE WITH THIS SW
CONUS LONG WAVE. THE LATEST MODEL RUNS PROBABLY STILL TRYING TO GET A
HANDLE ON THIS PROCESS AND IT WILL BE SUBJECT TO CHANGE...BUT THE
CURRENT SIGNAL SUGGESTS AT LEAST A DECENT SIZED PIECE OF WAVE ENERGY
EJECTING OUT OF THE SOUTHERN PLAINS AND THEN SOMEWHERE UP THE OH
RVR VALLEY OR EVEN FURTHER TO THE NORTHWEST SUNDAY INTO MONDAY. WITH
COLD AIR IN PLACE...THIS COULD SPELL AN EXTENDED PERIOD OF SNOW
MOVING UP ACRS PORTIONS OR ALL OF THE DVN CWA STARING OUT LATE SAT
NIGHT IN THE SOUTHWEST...AND THEN CONTINUING THROUGH LATE SUNDAY
NIGHT OR EARLY MON MORNING. THE CURRENT MODELS INCLUDING THE 12Z RUN
GFS AND ECMWF SUGGEST THE BETTER MOISTURE TRANSPORT TO FUEL HEAVIER
PRECIP TO GET PINCHED OFF/REMAIN TO THE SOUTH AND SOUTHEAST OF THE
LOCAL FCST AREA...WITH JUST SECONDARY SNOWS OF 1-3 INCHES ACRS THE
DVN CWA BY 12Z MON...SNOW MOVING OUT JUST AFTER THAT TIME-FRAME. BUT
THE DURATION/24 HRS OF ROUNDS OF AT LEAST LIGHT TO OCCASIONAL
MODERATE SNOW AND HIGHER LSR/S SUGGEST AMOUNTS COULD ADD UP TO BE
MORE. IF THE MOISTURE CONVEYOR IS LESS IMPEDED AND THE SYSTEM PULLS
UP FURTHER TO THE NORTHWEST...THERE MAY BE THE POTENTIAL FOR A MORE
SIGNIFICANT WINTER STORM IN PORTIONS OF OR CLOSE TO THE LOCAL AREA.
A WINDOW TO WATCH FOR SURE...AND WILL HAVE TO SEE HOW ADDITIONAL
MODEL RUNS BEHAVE AND HANDLE THE PHASING PROCESS. WILL RAISE THE CHC
POPS FOR NOW FOR SUNDAY NIGHT.

NEXT MONDAY AND TUESDAY...THE LONGER RANGE SIGNALS SUGGEST THAT
AFTER WHAT KIND OF SYSTEM CAN MAKE IT THROUGH OR CLOSE TO THE AREA
SUNDAY INTO EARLY MONDAY...A VERY COLD AIRMASS THEN LOOMS ACRS
CANADA. THE FRESHLY PHASED L/W TROF WILL THEN BECOME COLD CORE AND
ACT AS AN ARCTIC CONDUIT ALLOWING A COLD DUMP DOWN THE NORTHERN
PLAINS AND UPPER MIDWEST LATER MONDAY INTO TUE. THE 12Z GFS HAS A
FRIGID H85 MB COLD POOL OF -20 TO -26C BARRELING IT/S WAY DOWN
ACRS MOST OF THE CWA BY 12Z TUE...THE 12Z ECMWF IS ADVERTISING -19 TO
-21C. EVEN WITH MIXING WINDS WHICH WILL BE BRISK IN THIS TYPE OF
CAA UNDER CYCLONIC FLOW...TEMPS BY TUE MORNING MAY GO SUB-ZERO. MAY
BE WIND CHILL ADVISORY CRITERIA ATTAINED IN PORTIONS OF THE AREA LATE
MON NIGHT AND THROUGH MIDDAY TUE. WELL AGAIN...MANY SYSTEMS AND
PHASING PROCESSES TO GO THROUGH TO GET TO THIS EXTENDED PERIOD BUT
WILL START TO TREND TEMPS DOWN.     ..12..

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING)
ISSUED AT 543 PM CST TUE DEC 3 2013

WARM FRONT EXTENDS BETWEEN KMLI AND KBRL. NORTH OF THE WARM
FRONT WIDESPREAD FOG AND LOW CLOUDS WERE RESULTING IN IFR TO
LIFR CONDITIONS WITH POCKETS OF VLIFR. SOUTH OF THE WARM FRONT
SOME AREAS OF MVFR CONDITIONS WERE FOUND INCLUDING AT KBRL.
OVERALL...CONDITIONS WILL LIKELY BE THE WORST AT KDBQ WHERE LOW
CLOUDS...DENSE FOG AND DRIZZLE TO RESULT IN CONTINUATION OF LIFR
TO VLIFR CONDITIONS THROUGH WED AM. KBRL MAY REMAIN PREDOMINATELY
MVFR UNTIL OVERNIGHT AND KMLI BEING NEAR THE WARM FRONT COULD SEE
SOME IMPROVEMENT TO MVFR THIS EVENING WHILE KCID SHOULD STAY
GENERALLY IFR OR LOWER. ALL SITES SHOULD THEN LOWER ONCE AGAIN
OVERNIGHT TO IFR/LIFR WITH SOME VLIFR IN DENSE FOG... LOW CLOUDS
AND DRIZZLE AND REMAIN SO UNTIL LATER WED AM INTO WED AFTN WHEN A
COLD FRONT APPROACHES. THE COLD FRONT SHOULD DISSIPATE DENSE FOG
BUT MAINTAIN IFR/MVFR CONDITIONS IN LIGHT FOG AND LOW CLOUDS WITH
SOME LIGHT RAIN.

&&

.DVN WATCHES/WARNINGS/ADVISORIES...
IA...DENSE FOG ADVISORY UNTIL NOON CST WEDNESDAY FOR BENTON-BUCHANAN-
     CLINTON-DELAWARE-DUBUQUE-JACKSON-JONES-LINN.

     DENSE FOG ADVISORY UNTIL NOON CST WEDNESDAY FOR CEDAR-HENRY IA-
     IOWA-JEFFERSON-JOHNSON-KEOKUK-LOUISA-MUSCATINE-SCOTT-VAN
     BUREN-WASHINGTON.

IL...DENSE FOG ADVISORY UNTIL NOON CST WEDNESDAY FOR CARROLL-JO
     DAVIESS-STEPHENSON-WHITESIDE.

     DENSE FOG ADVISORY UNTIL NOON CST WEDNESDAY FOR ROCK ISLAND.

MO...NONE.
&&

$$

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