000
FXUS63 KDVN 092139
AFDDVN

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
339 PM CST MON DEC 9 2013

.SYNOPSIS...
ISSUED AT 337 PM CST MON DEC 9 2013

LATEST SFC ANALYSIS WAS INDICATING UPSTREAM RIDGE AXIS PUSHING
EASTWARD ACRS THE MO RVR VALLEY INTO SOUTHWESTERN MN ATTM...WHILE
CLIPPER TYPE LOW PRESSURE WAS ORGANIZING ACRS FAR SOUTHEASTERN
SASKATCHEWAN. PRESSURE FALLS REALLY BLOSSOMING ACRS THE CENTRAL
DAKOTAS TO LEE OF THE DEVELOPING CLIPPER...THIS FEATURE TO TAKE AIM
AT NORTHWEST INTO CENTRAL WI BY 12Z TUE. OTHERWISE COLD AMBIENT
TEMPS HOLDING STEADY OR EVEN LOOSING GROUND THIS AFTERNOON IN
ONGOING LLVL COLD AIR ADVECTION MACHINE FROM THE WEST. WIND CHILLS
IN THE -10 TO -15F RANGE FOR MUCH OF THE AFTERNOON NORTH OF I80 AND
WEST OF THE MS RVR.

&&

.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 337 PM CST MON DEC 9 2013

TONIGHT...AS THE SFC RIDGE APPROACHES...EXPECT WESTERLY SFC WINDS TO
DROP TO 5-10 MPH AFTER 00Z AND STAY DOWN THROUGH ROUGHLY 06Z-07Z
TONIGHT BUT BACKING TO THE SOUTHWEST AS THEY DO. AMBIENT TEMPS ALONG
AND NORTH OF I80...AND FROM THE QUAD CITIES TO EAST OF GALENA IN FAR
NW IL COULD BOTTOM OUT IN THE -2 TO -6 DEGREE RANGE FROM 01Z-06Z
BEFORE INCREASING AGAIN WITH SOUTHWEST SFC WIND INCREASE LATE AS THE
CLIPPER PUSHES CLOSER. EVEN WITH WINDS DROPPING DOWN INTO THE 5-10
MPH RANGE...MUCH OF THIS AREA WILL BE CLOSE TO OR TICKLING WIND
CHILL ADVISORY FROM 02Z TO 08Z OR SO. WILL ISSUE A SPECIAL WX
STATEMENT FOR THE WIND CHILLS...AND BRIEF INCOMING EVENING SHIFT THAT
IF MORE TEMPS BOTTOM OUT CLOSER TO THE -3 TO -6 RANGE A WC ADVISORY
WILL BE NEEDED. FOR NOW WILL ADVERTISE BOTTOM-OUT TEMPS MORE IN THE
WAY OF -1 TO -3 IN THESE AREAS BANKING ON MIXING WINDS TO KEEP TEMPS
FROM DROPPING CLOSER TO THE SFC DPTS 0F -4 TO -8F. WILL GO WITH ZERO
TO 5 ABOVE IN THE FAR EAST AND SOUTHERN CWA UNDER ONGOING CIRRUS
STREAM. AS FOR THE CLIPPER AS IT APPROACHES WI LATE TONIGHT...
INCOMING TIGHTENING CYCLONIC GRADIENT WILL CREATE A SOUTHWESTERLY
SFC WIND SURGE OF 15-20 MPH AFTER 08Z. THIS INITIAL SURGE WILL ALSO
CREATE WIND CHILLS NEAR ADVISORY CRITERIA BEFORE SFC TEMPS RECOVER
UPWARD SOME. MID AND HIGH LEVEL CLOUDS TO OVERCOME MUCH OF THE AREA
AHEAD OF THE CLIPPER LATER TONIGHT...AND IF ENOUGH SATURATION IN
THE LOW TO MID LEVELS...THERE MAY EVEN BE SOME LIGHT SNOW BREAKING
OUT NORTH OF THE HWY 30 CORRIDOR WEST OF THE MS RVR BEFORE 12Z...AND
SPREADING EAST OF THE RIVER THROUGH 15Z. WILL ADVERTISE FLURRIES
FOR NOW IN THESE AREAS. WILL ALSO RE-INTRODUCE PATCHY BLOWING/
DRIFTING SNOW LATE TONIGHT IN AREAS WITH 2-3+ INCHES OF POWDERY SNOW
COVER BECAUSE OF THE SOUTHWEST SFC WIND INCREASE.

TUESDAY...WILL WALK OUT THE FLURRIES IN THE NORTHEASTERN DVN CWA
THOUGH MID MORNING...AND STILL TOUCH UPON SOME BLOWING SNOW THROUGH
EARLY AFTERNOON WITH BRISK SOUTHWESTERLY WINDS OF 15 TO 25 MPH
BECOMING WESTERLY AS THE DAY PROGRESSES AND THE CLIPPER MIGRATES
EASTWARD ACRS LOWER MI. WITH THE MODERATING AIR FROM THE SOUTHWEST
DRAWN UP BY THE CLIPPER SYSTEM...WILL GO WITH HIGH TEMPS IN THE MID
TO UPPER TEENS NORTH OF I80...TO THE LOW TO MID 20S SOUTH OF I80.
    ..12..

.LONG TERM...(TUESDAY NIGHT THROUGH NEXT MONDAY)
ISSUED AT 337 PM CST MON DEC 9 2013

FORECAST FOCUS ON ACTIVE PATTERN WITH SEVERAL CLIPPER SYSTEMS AND
EVEN A SOUTHERN STREAM WINTER STORM BRINGING ACCUMULATING SNOWS TO
THE CWA THIS EXTENDED PERIOD. TEMPERATURES TO REMAIN BELOW TO WELL
BELOW NORMAL.

TUESDAY NIGHT AND WEDNESDAY...WITH HEIGHTS FALLING IN THE UPPER
MIDWEST THE NEXT CLIPPER SYSTEM WILL BE TRACKING FARTHER TO THE
SOUTH AND IS STRONGER THAN EARLIER MODEL RUNS DEPICTED. SURFACE LOW
WILL BE MOVING FROM THE NORTHERN PLAINS TO SOUTHERN IA WHICH SHOULD
LAY DOWN A BAND OF AT LEAST 1-3 INCH SNOW FROM THE I-80 CORRIDOR AND
POINTS TO THE NORTH. CAN`T RULE OUT A NARROW BAND OF 4 OR 5 INCHES
BUT HARD TO PIN DOWN THE EXACT LOCATION AT THIS POINT. AMOUNTS SOUTH
OF THE INTERSTATE SHOULD BE LESS THAN AN INCH. THIS LOOKS TO BE
ABOUT A 12 HOUR EVENT WITH ABOUT 6 HOURS OF MODERATE FORCING ALONG
WITH A 200 MB DENDRITIC GROWTH ZONE DEPTH THAT SHOULD PRODUCE A
PERIOD OF MODERATE SNOW. SIGNIFICANTLY LOWERING CONDENSATION
PRESSURE DEFICITS WOULD SUGGEST THE SNOW TO BEGIN IN OUR NW COUNTIES
EARLY TUESDAY EVENING WITH THE SNOW EXITING OUR EASTERN CWA LATER
WEDNESDAY MORNING. MOISTURE IS LIMITED BUT THIS WILL BE ANOTHER
ARCTIC FLUFF WITH ABOUT 20:1 TO 25:1 SNOW/WATER RATIO. WINDS
INCREASE TO AROUND 20 MPH ON WEDNESDAY SO SOME DRIFTING IS POSSIBLE.

FRIDAY AND SATURDAY...OPERATIONAL MODELS SIMILAR IN TRACKING A
WINTER STORM IN THE SOUTHERN STREAM INTO THE DVN CWA. THE ECMWF HAS
SPREAD THE SNOW FARTHER NORTH INTO THE CWA COMPARED TO YESTERDAY.
ACCUMULATING SNOWS LOOK LIKELY ESPECIALLY IN OUR SE HALF CWA BUT
THIS MAY CHANGE AS WE GET CLOSER TO THE EVENT.

SUNDAY AND MONDAY...OPERATIONAL MODELS COMING IN MUCH COLDER THAN
PREVIOUS RUNS WITH A DEEPENING TROUGH INTO THE MIDWEST AND GREAT
LAKES. THIS WOULD DROP MINIMUM TEMPERATURES INTO THE SINGLE DIGITS
WITH HIGHS ONLY IN THE TEENS. HOWEVER...IF LATER MODELS RUNS DO NOT
DIG THE TROUGH AS FAR SOUTH THEN READINGS WILL NOT BE AS COLD.

NEXT WEEK...ECMWF STILL SHOWS A NICE MODERATION IN TEMPERATURES FOR
MID TO LATE WEEK BUT HOW WARM IT GETS WILL DEPEND ON SNOW COVER/FOG/
STRATUS. BRUTALLY COLD AIR WILL BE MOVING INTO WESTERN CANADA WITH
850 MB TEMPERATURES COLDER THAN -35C! ONLY A MATTER OF TIME BEFORE
THE COLDEST AIR OF THE SEASON ARRIVES AND THE LATTER PORTION OF
DECEMBER LOOKS BRUTALLY COLD. SO IF YOU THOUGHT THIS HAS BEEN COLD...

HAASE

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1142 AM CST MON DEC 9 2013

VFR TAF CYCLE THROUGH AT LEAST MIDNIGHT...JUST GUSTY WEST WINDS
THIS AFTERNOON UP TO 20+ KTS AT TIMES...THEN DECREASING BECOMING
SOUTHWESTERLY THIS EVENING. A LOW CHC FOR BLOWING SNOW VSBY
RESTRICTIONS TO 4-6SM THIS AFTERNOON AT CID AND DBQ. THEN A
CLIPPER LOW PRESSURE SYSTEM WILL SKIRT ACRS MN AND WI LATE
TONIGHT AND FRI MORNING. THIS SYSTEM MAY BRING CLOSE TO MVFR CIGS
AT CID AND DBQ...AS WELL AS SOME FLURRIES OR EVEN LIGHT SNOW
ESPECIALLY AT DBQ FROM 11Z-15Z TUE MORNING. WILL PUT VCSH IN THE
TAFS FOR NOW AT CID/DBQ DURING THAT WINDOW. SOUTHWEST WINDS
INCREASING LATE TONIGHT TO 15-25 KTS AND THEN BECOMING WEST BY
LATE TUE MORNING.   ..12..


&&

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

$$

SYNOPSIS...12
SHORT TERM...12
LONG TERM...HAASE
AVIATION...12