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000
FXUS63 KDVN 030549
AFDDVN

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
1149 PM CST MON MAR 2 2015

.UPDATE...
ISSUED AT 950 PM CST MON MAR 2 2015

WINTRY MIXED PCPN EVENT STILL ON TRACK OVERNIGHT AND TUESDAY WITH
INITIALLY SNOW BUT EVENTUAL TRANSITION TO MIX OF SLEET/FREEZING
RAIN AND RAIN ESPECIALLY SOUTH HALF AS TEMPS WARM ABOVE FREEZING
ALOFT AND AT THE SFC. SOME INDICATIONS THAT THE HEAVIEST PCPN
(AROUND 0.1 INCH TO POSSIBLY NEAR 0.2 INCH) WILL FAVOR PORTIONS
OF SOUTHEAST HALF OF CWA WITH SOME SIGNAL FOR POTENTIAL MESOSCALE
BAND PORTIONS OF FAR EASTERN IA AND NORTHWEST IL... WHICH IF
OCCURS COULD RESULT IN NARROW SWATH OF HIGHER SNOW AND SLEET
ACCUMS GREATER THAN 1 INCH TO POSSIBLY AROUND 2 INCHES. ANY ICING
STILL LOOKS AROUND A TRACE TO A FEW HUNDRETHS OF AN INCH MAINLY
SOUTH HALF.

&&

.SYNOPSIS...
ISSUED AT 338 PM CST MON MAR 2 2015

12Z UA ANALYSIS HAS AN 850MB ARCTIC HIGH BETWEEN KOAX AND KTOP.
CONSIDERABLE MOISTURE WAS SOUTH OF THE 850MB ARCTIC FRONT IN TEXAS.
SATELLITE TRENDS THROUGH MID AFTERNOON SHOW INCREASING MID LEVEL
CLOUDS ACROSS THE MIDWEST.

18Z SFC ANALYSIS AS THE ARCTIC HIGH OVER ILLINOIS WITH WARM
SOUTHERLY RETURN FLOW ACROSS THE PLAINS. DEW POINTS WERE IN THE
SINGLE DIGITS AND TEENS ACROSS THE GREAT LAKES AND UPPER MIDWEST
WITH 20S AND 30S IN THE PLAINS.

&&

.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 338 PM CST MON MAR 2 2015

QUIET AND DRY CONDITIONS WITH INCREASING CLOUDS WILL BE SEEN LATE
THIS AFTERNOON AND EVENING. ATTENTION THEN TURNS TO THE WEAK STORM
SYSTEM.

AFTER MIDNIGHT...THE ATMOSPHERE WILL RAPIDLY SATURATE AS MOISTURE
AND WARMER AIR MOVE IN ALOFT. THERMAL PROFILES POINT TO THE
POTENTIAL FOR THE ATMOSPHERIC COLUMN TO COOL AS PRECIPITATION
DEVELOPS. THUS PRECIPITATION WILL INITIALLY BEGIN AS SNOW.

AS EVEN WARMER AIR BEGINS MOVING IN ALOFT IN THE PRE-DAWN HOURS...A
MIXTURE OF SNOW AND SLEET WILL DEVELOP ACROSS THE SOUTH THIRD OF THE
AREA THAT SLOWLY MOVES UP TO THE I-80 CORRIDOR THROUGH SUNRISE.
AREAS NORTH OF HIGHWAY 30 SHOULD SEE SNOW DEVELOP OR CONTINUE
THROUGH SUNRISE.

AFTER SUNRISE...WARMING OF THE ATMOSPHERE WILL ALLOW THE SNOW/SLEET
MIXTURE TO TRANSITION OVER TO ALL RAIN ALONG/SOUTH OF I-80. DURING
THIS TRANSITION A BRIEF PERIOD OF FREEZING RAIN WILL BE POSSIBLE.
AREAS NORTH OF HIGHWAY 30 WILL SEE A SNOW/SLEET MIXTURE DEVELOP.

AS FORCING MOVES EAST OF THE AREA BY MID DAY TUESDAY...PRECIPITATION
INTENSITY WILL DECREASE. A COLD FRONT MOVING THROUGH THE AREA
TUESDAY AFTERNOON WILL ALLOW A RAIN/SNOW MIX DEVELOP ACROSS THE AREA
AS THE ATMOSPHERE SLOWLY COOLS.

HEADLINES FOR A WINTER WEATHER ADVISORY HAVE BEEN ISSUED STARTING
AROUND 3 AM TUESDAY AND CONTINUING THROUGH TUESDAY MORNING. ONE
REASON IS FOR THE MORNING COMMUTE.

ANY ICE THAT DEVELOPS DURING THE TRANSITION FROM SNOW/SLEET TO RAIN
ALONG AND SOUTH OF I-80 WILL QUICKLY MELT AS TEMPERATURES CLIMB
ABOVE FREEZING.

AS FOR SNOW/SLEET AMOUNTS...LESS THAN AN INCH OF ACCUMULATION SHOULD
BE SEEN ALONG/SOUTH OF I-80. MOST OF THIS NEW SNOW/SLEET WILL MELT
AS TEMPERATURES CLIMB ABOVE FREEZING. NORTH OF HIGHWAY 30...
SNOW/SLEET ACCUMULATIONS AROUND AN INCH WILL BE POSSIBLE.

.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 338 PM CST MON MAR 2 2015

OVERVIEW...UPPER-LEVEL PATTERN WILL SLOWLY EVOLVE INTO A SPLIT FLOW
THROUGH THE WEEK. THE POLAR BRANCH OF THIS FLOW WILL BRING MORE
ARCTIC AIR INTO THE MIDWEST AS IT BECOMES NORTHWESTERLY. A LARGE MID
TO UPPER-LEVEL RIDGE WILL DEVELOP OVER THE EASTERN PACIFIC AND
WESTERN UNITED STATES INTO THIS WEEKEND. THE GENERAL TREND THROUGH
THE WEEKEND AND INTO EARLY NEXT WEEK WILL BE FOR THE RIDGE AXIS TO
SHIFT EASTWARD INTO THE MIDWEST...BRINGING MODERATING TEMPERATURES.
CURRENTLY THIS FORECAST PERIOD LOOKS VERY DRY.

TUESDAY NIGHT AND WEDNESDAY...STRONG NEGATIVE 1000-500 MB THERMAL
ADVECTION WILL DOMINATE THIS PERIOD AND WILL NOT DIMINISH UNTIL THE
MID-LEVEL TROUGH AXIS MOVES EAST OF THE AREA LATE WED NIGHT.
THICKNESS VALUES WILL DROP FROM NEAR 540 DAM TUE EVENING TO 516 DAM
BY LATE WED AFTN. AT THE SFC...EXPECT GUSTY NW WINDS UP TO 25-30 MPH
IN A WELL-MIXED BOUNDARY LAYER ENVIRONMENT. HIGH TEMPS WILL BE IN
THE TEENS WITH LOW 20S FAR SOUTHERN CWA (~25 F DEGREES BELOW AVG).

WEDNESDAY NIGHT...ANOTHER ARCTIC HIGH WILL MOVE THROUGH THE PLAINS.
THE RIDGE AXIS WILL STAY WEST OF E IOWA AND PARALLEL THE MISSOURI
RIVER VALLEY REGION WHICH MEANS SFC WINDS WILL NOT FULLY DECOUPLE.
ANTICIPATE WIND CHILLS BETWEEN 20 TO 25 BELOW ALONG THE I-80
CORRIDOR AND POINTS NORTH...A WIND CHILL ADVISORY MAY BE NEEDED.

A FEW LOCATIONS NORTH OF THE QUAD CITIES MAY APPROACH RECORD LOWS.
TEMPS WILL RANGE FROM THE LOWER SINGLE DIGITS NEAR BURLINGTON TO
CLOSE TO -10 F IN THE N/NW DVN CWA. FAVORED COLD VALLEY LOCATIONS
WILL PROBABLY BE COLDER.

THURSDAY AND FRIDAY...STILL COLD AND QUIET ON THU WITH LIGHT WINDS.
HIGHS AGAIN IN THE LOWER 20S ACROSS THE SW WITH TEENS ELSEWHERE.
850-500MB FLOW BECOMES ZONAL WHICH WILL PUSH 850 MB TEMPS TO -4 C BY
FRI AFTN AND 1000-500 MB THICKNESS TO ~540 DAM. SHOULD FINALLY SEE
TEMPS ABOVE FREEZING ACROSS MOST OF E IOWA/W ILLINOIS ON FRI.

SATURDAY AND SUNDAY...OVERALL PATTERN IS FOR DRY AND WARMER WEATHER.
MODEL DIFFERENCES ARE WITH RESPECT TO THE DEGREE OF WARMING. THE GFS
HAS 30S/40S WHILE THE ECMWF HAS 40S/50S. SUPERBLEND IS A GOOD
COMPROMISE THIS FAR OUT WITH UPPER 30S TO UPPER 40S AND THE
TYPICAL NE-TO-SW GRADIENT.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1147 PM CST MON MAR 2 2015

LOW LEVEL WIND SHEAR IS STILL POSSIBLE OVERNIGHT INTO EARLY
TUESDAY AM WITH STRENGTHENING LOW LEVEL JET. MODELS THOUGH VARY ON
STRENGTH OF WINDS 1500-2000 FT AGL (30-40 KTS) AND WITH EXPECTED
INCREASE IN SURFACE WINDS WITH SOME GUSTS HAVE CONTINUED TO LEAVE
OUT MENTION ATTIM BUT CONTINUE TO MONITOR. OTHERWISE... OVERNIGHT
AND TUESDAY AM EXPECT CONDITIONS TO DETERIORATE INTO MVFR TO
POSSIBLY AREAS OF IFR WITH A SHOWERY WINTRY MIX OF PCPN ACROSS THE
AREA. PCPN WILL BE MAINLY LIGHT WITH TYPES FAVORING MAINLY SLEET/
SNOW NORTH OF I-80 WITH FREEZING RAIN/SLEET TRANSITION TO RAIN
SOUTH WHERE MINOR GLAZING OF ICE ACCUM POSSIBLE. PCPN TO DIMINISH
IN COVERAGE BY LATE AM THROUGH MIDDAY WITH MVFR TO POSSIBLY AREAS
OF IFR CONDITIONS CONTINUING THROUGH AFTN AHEAD OF A COLD FRONT
WHICH WILL PASS THROUGH THE TERMINALS 19-23Z AND MAY BE
ACCOMPANIED BY FLURRIES OR BRIEF PERIOD OF LIGHT SNOW ESPECIALLY
NORTHEAST IA.

&&

.CLIMATE...
ISSUED AT 338 PM CST MON MAR 2 2015

RECORD LOWS FOR MARCH 5...

MOLINE.........-13 IN 1960
CEDAR RAPIDS...-12 IN 1960
DUBUQUE........-9 IN 1978
BURLINGTON.....-13 IN 1960

&&

.DVN WATCHES/WARNINGS/ADVISORIES...
IA...WINTER WEATHER ADVISORY FROM 3 AM TO NOON CST TUESDAY FOR BENTON-
     BUCHANAN-CEDAR-CLINTON-DELAWARE-DUBUQUE-IOWA-JACKSON-
     JOHNSON-JONES-KEOKUK-LINN-LOUISA-MUSCATINE-SCOTT-WASHINGTON.

     WINTER WEATHER ADVISORY FROM 3 AM TO 9 AM CST TUESDAY FOR DES
     MOINES-HENRY IA-JEFFERSON-LEE-VAN BUREN.

IL...WINTER WEATHER ADVISORY FROM 3 AM TO NOON CST TUESDAY FOR BUREAU-
     CARROLL-HENRY IL-JO DAVIESS-MERCER-PUTNAM-ROCK ISLAND-
     STEPHENSON-WHITESIDE.

     WINTER WEATHER ADVISORY FROM 3 AM TO 9 AM CST TUESDAY FOR
     HANCOCK-HENDERSON-MCDONOUGH-WARREN.

MO...WINTER WEATHER ADVISORY FROM 3 AM TO 9 AM CST TUESDAY FOR CLARK-
     SCOTLAND.

&&

$$

UPDATE...05
SYNOPSIS...08
SHORT TERM...08
LONG TERM...UTTECH
AVIATION...05
CLIMATE...UTTECH