000
FXUS63 KDVN 090524
AFDDVN

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
1124 PM CST SUN DEC 8 2013

.SYNOPSIS...
ISSUED AT 229 PM CST SUN DEC 8 2013

ANALYSIS AT 2 PM SHOWS WIDESPREAD LIGHT TO LOCALLY MODERATE SNOW OVER
THE UPPER MIDWEST. RADAR TRENDS SUPPORT SATELLITE OF SNOW ENDING FROM
SOUTH TO NORTH OVER THE FORECAST REGION THE NEXT 6 HOURS. LOCAL REPORTS
SHOWS .5 TO 2 INCH SNOW AMOUNTS OVER THE REGION. UPPER AIR ANALYSIS
SUPPORTS TRENDS OF CLEARING BY MONDAY AM. ZONAL FLOW SUPPORTS WARMER
TEMPERATURES AFTER MONDAY NIGHT AND THEN MOSTLY DRY TO DRY NEXT COUPLE
OF DAYS.

&&

.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 229 PM CST SUN DEC 8 2013

TONIGHT...LINGERING SNOWS WILL END OVER NORTHERN 1/3 TO 1/2 OF THE AREA
BETWEEN 6 AND 9 AM. ANY ADDITIONAL SNOW TOTALS WILL BE A QUARTER TO
THREE QUARTERS OF AN INCH FROM HIGHWAY 30 TO HIGHWAY 20 CORRIDORS.
PATCHY LIGHT FREEZING DRIZZLE WILL BE POSSIBLE INTO THE MID TO
LATE EVENING THAT MAY PUT A VERY MINOR GLAZE OF EXPOSED SURFACES.
SKIES WILL BEGIN TO CLEAR OVERNIGHT WITH MINS UPPER TEENS
NORTHWEST TO THE MIDDLE TEENS WITH GOOD COLD AIR ADVECTION. LOWS
WILL BE AROUND 8 AM WITH POSSIBLE COLDER TEMPERATURES NEEDED AT
LEAST WEST SECTIONS FOR LATER SHIFTS TO REASSESS IF CLEARING IS
FASTER.

MONDAY...SUNNY AND COLD WITH TEMPERATURES VERY SLOWLY RISING DUE
TO COLD AIR ADVECTION AND A FRESH SNOW PACK OF 1 TO LOCALLY 3 PLUS
INCHES. WESTERLY WINDS OF 10 TO 20 MPH WITH HIGH TEMPERATURES OF
10 TO 20 FROM NW TO SE. WIND CHILL VALUES WILL BE -5 TO +5 MUCH OF
THE DAY FOR A VERY COLD DECEMBER DAY.

.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 229 PM CST SUN DEC 8 2013

FORECAST FOCUS ON WELL BELOW NORMAL TEMPERATURES THROUGH MID WEEK
THEN SOME MODERATION IN TEMPERATURES AND MORE SNOW POSSIBLE LATE IN
THE WEEK. AN INTENSE STORM SYSTEM THE FOLLOWING WEEK PUSHES TOWARDS
THE PACIFIC NORTHWEST RETURNING ZONAL FLOW ALOFT TO THE MIDWEST.
THIS SHOULD ALLOW TEMPERATURES TO WARM INTO THE 40S WEEK 2...BUT
BRUTAL COLD AIR WILL RETURN DURING THE LATTER PORTION OF DECEMBER.

MONDAY NIGHT AND TUESDAY...VERY COLD AS NORTHWEST FLOW REMAINS
LOCKED IN PLACE. A WEAK CLIPPER WILL BE TRACKING ACROSS THE UPPER
MIDWEST AND NORTHERN GREAT LAKES. THIS SYSTEM COMBINED WITH ARCTIC
HIGH PRESSURE IN THE LOWER MS VALLEY WILL CREATE A TIGHTENING
GRADIENT IN THE DVN CWA. WEST WINDS WILL GUST TO 25 TO 30 MPH LATE
MONDAY NIGHT AND TUESDAY. THIS WILL CREATE WIND CHILLS DOWN TO 15 TO
20 BELOW IN OUR NORTHERN CWA.

TUESDAY NIGHT INTO WEDNESDAY...A SHORT WAVE IN THE FLOW WILL ARRIVE
PRODUCING A PERIOD OF LIGHT SNOW AND/OR FLURRIES MAINLY OVER THE
NORTHERN HALF OF THE CWA. MOISTURE IS LIMITED SO ACCUMULATIONS IF
ANY APPEAR TO BE MINOR. BEHIND THE WAVE ANOTHER 1040 MB ARCTIC HIGH
SETTLES INTO THE MIDWEST...KEEPING TEMPERATURES WELL BELOW NORMAL.

WEDNESDAY NIGHT THROUGH SUNDAY...SPLIT FLOW TEMPORARILY DEVELOPS
PROVIDING MODERATING TEMPERATURES. THE NEXT CHANCE OF SNOW WILL BE
FRIDAY INTO SATURDAY. HOWEVER...MODELS DIFFER ON HOW FAR TO SPREAD
THE SNOW INTO THE DVN CWA. A STORM SYSTEM IN THE SOUTHERN STREAM
BRINGS ANOTHER BOUT OF WINTRY PRECIPITATION TO THE SOUTHERN STATES.
THE ECMWF/GEM SPREAD THE ACCUMULATING SNOW NORTHWARD TO SOUTHEAST IA
AND WESTERN IL WITH THE REMAINDER OF THE CWA DRY AS STRONG ARCTIC
HIGH RESIDES OVER NORTHERN MN. ON THE OTHER HAND...THE GFS HAS A
WEAKER HIGH AND FARTHER NORTH ALLOWING FOR THE ACCUMULATING SNOW TO
PUSH INTO THE ENTIRE CWA. FOR NOW WE WILL HAVE CHANCE POPS FOR
FRIDAY THROUGH SATURDAY AND SEE HOW THE MODELS RESOLVE THIS
DISCREPANCY.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1120 PM CST SUN DEC 8 2013

THE LOW PRESSURE SYSTEM THAT CAUSED SUNDAYS SNOW WAS LOCATED OVER
SOUTHERN LAKE MICHIGAN LATE THIS EVENING AND WAS MOVING EAST AWAY
FROM THE REGION LOW CIGS AND LINGERING LIGHT SNOW TRAILING THE LOW
SHOULD ALSO MOVE OUT OF THE AREA EARLY THIS MORNING. THE MIX OF
MVFR AND IFR CIGS AND VSBYS SHOULD GIVE WAS TO FR CONDITIONS BY
12Z. FR CONDITIONS SHOULD REMAIN OVER THE AREA THROUGH MONDAY
EVENING.

&&

.DVN WATCHES/WARNINGS/ADVISORIES...
IA...WINTER WEATHER ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR BENTON-
     BUCHANAN-DELAWARE-DUBUQUE-LINN.

IL...NONE.
MO...NONE.
&&

$$

SYNOPSIS...NICHOLS
SHORT TERM...NICHOLS
LONG TERM...HAASE
AVIATION...DLF