Alert archive / Iowa / Winter Storm Watches in 2012

Winter Storm Watch 3, NWS Des Moines, IA

December 17, 201242 counties in Iowa

NWS Des Moines, IA issued this winter storm watch at Dec 17, 2012, 4:01 PM CST for 42 counties in Iowa. It took effect at Dec 19, 2012, 12:00 PM CST. It was in force for .

The area

The counties it named.

The facts

Issued
Dec 17, 2012, 4:01 PM CST (22:01 UTC)
In effect from
Dec 19, 2012, 12:00 PM CST
Expired
Dec 18, 2012, 3:24 PM CST
In force
Issued by
NWS Des Moines, IA
All 42 counties

Adair County, IA, Adams County, IA, Appanoose County, IA, Audubon County, IA, Black Hawk County, IA, Boone County, IA, Bremer County, IA, Butler County, IA, Calhoun County, IA, Carroll County, IA, Cass County, IA, Clarke County, IA, Crawford County, IA, Dallas County, IA, Davis County, IA, Decatur County, IA, Franklin County, IA, Greene County, IA, Grundy County, IA, Guthrie County, IA, Hamilton County, IA, Hardin County, IA, Jasper County, IA, Lucas County, IA, Madison County, IA, Mahaska County, IA, Marion County, IA, Marshall County, IA, Monroe County, IA, Polk County, IA, Poweshiek County, IA, Ringgold County, IA, Sac County, IA, Story County, IA, Tama County, IA, Taylor County, IA, Union County, IA, Wapello County, IA, Warren County, IA, Wayne County, IA, Webster County, IA, Wright County, IA

The radar

The Des Moines radar (KDMX), 7 km from the middle of the area, began a volume at 22:03 UTC, the scan nearest the moment this went out.

Open the radar archive at this moment

The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.

The nearest sounding before it

Omaha, NE (KOAX), launched 12:00Z, 10.0 hours before the alert went out and 229 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.

Skew-T log-pSkew-T log-p diagram, Omaha, NE at 12:00Z on 2012-12-17Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Omaha, NE at 12:00Z on 2012-12-17The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 97 square meters per square second.1939Sfc1 km3 km6 km9 kmRMLM
The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.
Mixed-layer CAPE
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
650 m above ground
0-6 km bulk shear
24 kt
0-1 km storm-relative helicity
97 m²/s²
0-3 km storm-relative helicity
106 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

113 
WWUS43 KDMX 172201
WSWDMX

URGENT - WINTER WEATHER MESSAGE
NATIONAL WEATHER SERVICE DES MOINES IA
401 PM CST MON DEC 17 2012

...FIRST MAJOR WINTER STORM TO AFFECT CENTRAL IOWA MIDWEEK...

.STRONG LOW PRESSURE WILL MOVE FROM COLORADO INTO THE OKLAHOMA
PANHANDLE ON WEDNESDAY BEFORE LIFTING NORTHEAST INTO ILLINOIS BY
THURSDAY. RAIN AND SNOW IS EXPECTED TO OVERSPREAD IOWA ON
WEDNESDAY BECOMING ALL SNOW WEDNESDAY NIGHT AND ENDING THURSDAY.
VERY STRONG NORTHWEST WINDS WILL PRODUCE CONSIDERABLE BLOWING AND
DRIFTING SNOW LATE WEDNESDAY NIGHT INTO THURSDAY.

IAZ025>028-033>039-044>050-057>062-070>075-081>086-092>097-180600-
/O.NEW.KDMX.WS.A.0003.121219T1800Z-121221T0000Z/
WRIGHT-FRANKLIN-BUTLER-BREMER-SAC-CALHOUN-WEBSTER-HAMILTON-HARDIN-
GRUNDY-BLACK HAWK-CRAWFORD-CARROLL-GREENE-BOONE-STORY-MARSHALL-
TAMA-AUDUBON-GUTHRIE-DALLAS-POLK-JASPER-POWESHIEK-CASS-ADAIR-
MADISON-WARREN-MARION-MAHASKA-ADAMS-UNION-CLARKE-LUCAS-MONROE-
WAPELLO-TAYLOR-RINGGOLD-DECATUR-WAYNE-APPANOOSE-DAVIS-
INCLUDING THE CITIES OF...CLARION...HAMPTON...ALLISON...WAVERLY...
SAC CITY...ROCKWELL CITY...FORT DODGE...WEBSTER CITY...ELDORA...
GRUNDY CENTER...WATERLOO...DENISON...CARROLL...JEFFERSON...
BOONE...AMES...MARSHALLTOWN...TOLEDO...AUDUBON...GUTHRIE CENTER...
ADEL...DES MOINES...NEWTON...GRINNELL...ATLANTIC...GREENFIELD...
WINTERSET...INDIANOLA...KNOXVILLE...OSKALOOSA...CORNING...
CRESTON...OSCEOLA...CHARITON...ALBIA...OTTUMWA...BEDFORD...
MOUNT AYR...LEON...CORYDON...CENTERVILLE...BLOOMFIELD
401 PM CST MON DEC 17 2012

...WINTER STORM WATCH IN EFFECT FROM WEDNESDAY AFTERNOON THROUGH
THURSDAY AFTERNOON...

THE NATIONAL WEATHER SERVICE IN DES MOINES HAS ISSUED A WINTER
STORM WATCH...WHICH IS IN EFFECT FROM WEDNESDAY AFTERNOON THROUGH
THURSDAY AFTERNOON. 

* TIMING...PRECIPITATION WILL OVERSPREAD CENTRAL IOWA ON WEDNESDAY
  AFTERNOON. SNOW IS EXPECTED ALONG AND NORTH OF AN ATLANTIC
  THROUGH BOONE TO WATERLOO LINE. RAIN IS EXPECTED IN SOUTHERN
  IOWA SOUTH OF A BEDFORD TO OSKALOOSA LINE. IN BETWEEN...A RAIN
  AND SNOW MIX IS EXPECTED. THIS PRECIPITATION WILL CHANGE TO ALL
  SNOW ON WEDNESDAY NIGHT BEFORE ENDING ON THURSDAY MORNING.

* STORM TOTAL SNOW ACCUMULATION...5 TO 8 INCHES OF SNOW IS
  EXPECTED IN THE WATCH AREA. LOCAL AMOUNTS OF UP TO 10 INCHES
  WILL BE POSSIBLE.

* WINDS/VISIBILITY...WINDS WILL BECOME VERY STRONG ON WEDNESDAY
  NIGHT FROM THE NORTH TO NORTHWEST. SUSTAINED WINDS OF 20 TO 30
  MPH ARE EXPECTED WITH GUSTS OVER 35 MPH POSSIBLE. THE STRONGEST
  WINDS ARE EXPECTED AROUND DAYBREAK ON THURSDAY WITH NEAR
  BLIZZARD CONDITIONS POSSIBLE WITH VISIBILITIES REDUCED BELOW ONE
  QUARTER OF A MILE FROM TIME TO TIME.  

* IMPACTS...VERY DANGEROUS CONDITIONS ARE EXPECTED TO DEVELOP ON
  WEDNESDAY NIGHT INTO THURSDAY MORNING. BE PREPARED FOR VERY
  DIFFICULT TRAVEL AND NEAR BLIZZARD CONDITIONS.


PRECAUTIONARY/PREPAREDNESS ACTIONS...

A WINTER STORM WATCH MEANS THERE IS A POTENTIAL FOR SIGNIFICANT
SNOW...SLEET...OR ICE ACCUMULATIONS THAT MAY IMPACT TRAVEL.
CONTINUE TO MONITOR THE LATEST FORECASTS.

&&

$$
4 follow-up statements
233 
WWUS43 KDMX 180253
WSWDMX

URGENT - WINTER WEATHER MESSAGE
NATIONAL WEATHER SERVICE DES MOINES IA
853 PM CST MON DEC 17 2012

...FIRST MAJOR WINTER STORM TO AFFECT CENTRAL IOWA MIDWEEK...

.STRONG LOW PRESSURE WILL MOVE FROM COLORADO INTO THE OKLAHOMA
PANHANDLE ON WEDNESDAY BEFORE LIFTING NORTHEAST INTO ILLINOIS BY
THURSDAY. RAIN AND SNOW IS EXPECTED TO OVERSPREAD IOWA ON
WEDNESDAY BECOMING ALL SNOW WEDNESDAY NIGHT AND ENDING THURSDAY.
VERY STRONG NORTHWEST WINDS WILL PRODUCE CONSIDERABLE BLOWING AND
DRIFTING SNOW LATE WEDNESDAY NIGHT INTO THURSDAY.

IAZ025>028-033>039-044>050-057>062-070>075-081>086-092>097-181100-
/O.CON.KDMX.WS.A.0003.121219T1800Z-121221T0000Z/
WRIGHT-FRANKLIN-BUTLER-BREMER-SAC-CALHOUN-WEBSTER-HAMILTON-HARDIN-
GRUNDY-BLACK HAWK-CRAWFORD-CARROLL-GREENE-BOONE-STORY-MARSHALL-
TAMA-AUDUBON-GUTHRIE-DALLAS-POLK-JASPER-POWESHIEK-CASS-ADAIR-
MADISON-WARREN-MARION-MAHASKA-ADAMS-UNION-CLARKE-LUCAS-MONROE-
WAPELLO-TAYLOR-RINGGOLD-DECATUR-WAYNE-APPANOOSE-DAVIS-
INCLUDING THE CITIES OF...CLARION...HAMPTON...ALLISON...WAVERLY...
SAC CITY...ROCKWELL CITY...FORT DODGE...WEBSTER CITY...ELDORA...
GRUNDY CENTER...WATERLOO...DENISON...CARROLL...JEFFERSON...
BOONE...AMES...MARSHALLTOWN...TOLEDO...AUDUBON...GUTHRIE CENTER...
ADEL...DES MOINES...NEWTON...GRINNELL...ATLANTIC...GREENFIELD...
WINTERSET...INDIANOLA...KNOXVILLE...OSKALOOSA...CORNING...
CRESTON...OSCEOLA...CHARITON...ALBIA...OTTUMWA...BEDFORD...
MOUNT AYR...LEON...CORYDON...CENTERVILLE...BLOOMFIELD
853 PM CST MON DEC 17 2012

...WINTER STORM WATCH REMAINS IN EFFECT FROM WEDNESDAY AFTERNOON
THROUGH THURSDAY AFTERNOON...

* TIMING...PRECIPITATION WILL OVERSPREAD CENTRAL IOWA ON 
  WEDNESDAY AFTERNOON. SNOW IS EXPECTED ALONG AND NORTH OF AN 
  ATLANTIC THROUGH BOONE TO WATERLOO LINE. RAIN IS EXPECTED IN 
  SOUTHERN IOWA SOUTH OF A BEDFORD TO OSKALOOSA LINE. IN 
  BETWEEN...A RAIN AND SNOW MIX IS EXPECTED. THIS PRECIPITATION 
  WILL CHANGE TO ALL SNOW ON WEDNESDAY NIGHT BEFORE ENDING ON 
  THURSDAY MORNING. 

* STORM TOTAL SNOW ACCUMULATION...5 TO 8 INCHES OF SNOW IS
  EXPECTED IN THE WATCH AREA. LOCAL AMOUNTS OF UP TO 10 INCHES
  WILL BE POSSIBLE WITH DRIFTS EVEN HIGHER. 

* WINDS/VISIBILITY...WINDS WILL BECOME VERY STRONG ON WEDNESDAY
  NIGHT FROM THE NORTH TO NORTHWEST. SUSTAINED WINDS OF 20 TO 30
  MPH ARE EXPECTED WITH GUSTS OVER 35 MPH POSSIBLE. THE STRONGEST
  WINDS ARE EXPECTED AROUND DAYBREAK ON THURSDAY WITH BLIZZARD OR NEAR
  BLIZZARD CONDITIONS POSSIBLE WITH VISIBILITIES REDUCED BELOW ONE
  QUARTER OF A MILE FROM TIME TO TIME.

* IMPACTS...VERY DANGEROUS CONDITIONS ARE EXPECTED TO DEVELOP ON 
  WEDNESDAY NIGHT INTO THURSDAY MORNING. BE PREPARED FOR VERY 
  DIFFICULT TRAVEL AND BLIZZARD OR NEAR BLIZZARD CONDITIONS. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A WINTER STORM WATCH MEANS THERE IS A POTENTIAL FOR SIGNIFICANT
SNOW...SLEET...OR ICE ACCUMULATIONS THAT MAY IMPACT TRAVEL...IN
THIS CASE SNOW. CONTINUE TO MONITOR THE LATEST FORECASTS. IF
FORECAST CONFIDENCE CONTINUES TO INCREASE...THIS WATCH MAY BE
UPGRADED TO A BLIZZARD WATCH ON TUESDAY.

&&

$$

SMALL
656 
WWUS43 KDMX 180943
WSWDMX

URGENT - WINTER WEATHER MESSAGE
NATIONAL WEATHER SERVICE DES MOINES IA
343 AM CST TUE DEC 18 2012

...MAJOR WINTER STORM TO AFFECT CENTRAL IOWA WEDNESDAY AND THURSDAY...

.A STRONG STORM WILL MOVE INTO THE OKLAHOMA PANHANDLE WEDNESDAY
AFTERNOON BEFORE LIFTING NORTHEAST INTO NORTH CENTRAL ILLINOIS BY
THURSDAY. RAIN AND SNOW IS EXPECTED TO OVERSPREAD IOWA WEDNESDAY
BECOMING ALL SNOW WEDNESDAY NIGHT AND ENDING THURSDAY. VERY STRONG
NORTHWEST WINDS WILL PRODUCE CONSIDERABLE BLOWING AND DRIFTING OF
SNOW AND NEAR BLIZZARD CONDITIONS LATE WEDNESDAY NIGHT INTO THURSDAY
RESULTING IN DANGEROUS TRAVEL OVER IOWA.

IAZ025>028-033>039-044>050-057>062-070>075-081>086-092>097-181745-
/O.CON.KDMX.WS.A.0003.121219T1800Z-121221T0000Z/
WRIGHT-FRANKLIN-BUTLER-BREMER-SAC-CALHOUN-WEBSTER-HAMILTON-HARDIN-
GRUNDY-BLACK HAWK-CRAWFORD-CARROLL-GREENE-BOONE-STORY-MARSHALL-
TAMA-AUDUBON-GUTHRIE-DALLAS-POLK-JASPER-POWESHIEK-CASS-ADAIR-
MADISON-WARREN-MARION-MAHASKA-ADAMS-UNION-CLARKE-LUCAS-MONROE-
WAPELLO-TAYLOR-RINGGOLD-DECATUR-WAYNE-APPANOOSE-DAVIS-
INCLUDING THE CITIES OF...CLARION...HAMPTON...ALLISON...WAVERLY...
SAC CITY...ROCKWELL CITY...FORT DODGE...WEBSTER CITY...ELDORA...
GRUNDY CENTER...WATERLOO...DENISON...CARROLL...JEFFERSON...
BOONE...AMES...MARSHALLTOWN...TOLEDO...AUDUBON...GUTHRIE CENTER...
ADEL...DES MOINES...NEWTON...GRINNELL...ATLANTIC...GREENFIELD...
WINTERSET...INDIANOLA...KNOXVILLE...OSKALOOSA...CORNING...
CRESTON...OSCEOLA...CHARITON...ALBIA...OTTUMWA...BEDFORD...
MOUNT AYR...LEON...CORYDON...CENTERVILLE...BLOOMFIELD
343 AM CST TUE DEC 18 2012

...WINTER STORM WATCH REMAINS IN EFFECT FROM WEDNESDAY AFTERNOON
THROUGH THURSDAY AFTERNOON...

* TIMING...PRECIPITATION WILL OVERSPREAD CENTRAL IOWA WEDNESDAY
  AFTERNOON. SNOW IS EXPECTED ALONG AND NORTH OF AN ATLANTIC
  THROUGH BOONE TO WATERLOO LINE. RAIN IS EXPECTED IN SOUTHERN
  IOWA SOUTH OF A BEDFORD TO OSKALOOSA LINE. IN BETWEEN...A RAIN
  AND SNOW MIX IS EXPECTED. THIS PRECIPITATION WILL CHANGE TO ALL
  SNOW LATE WEDNESDAY EVENING BEFORE ENDING THURSDAY MORNING.

* STORM TOTAL SNOW ACCUMULATION...5 TO 8 INCHES OF SNOW IS
  EXPECTED IN THE WATCH AREA. LOCAL AMOUNTS OF UP TO 10 INCHES
  WILL BE VERY POSSIBLE WITH DRIFTS EVEN HIGHER.

* WINDS/VISIBILITY...WINDS WILL BECOME VERY STRONG WEDNESDAY NIGHT
  FROM THE NORTH NORTHWEST. SUSTAINED WINDS OF 25 TO 33 MPH ARE
  EXPECTED WITH GUSTS OVER 45 MPH POSSIBLE. THE STRONGEST WINDS ARE
  EXPECTED A FEW HOURS PRIOR TO DAYBREAK THROUGH NOON THURSDAY.
  BLIZZARD OR NEAR BLIZZARD CONDITIONS MAY OCCUR WITH VISIBILITIES
  REDUCED BELOW ONE QUARTER OF A MILE FROM TIME TO TIME.

* IMPACTS...VERY DANGEROUS CONDITIONS ARE EXPECTED TO DEVELOP ON
  WEDNESDAY NIGHT INTO THURSDAY MORNING. BE PREPARED FOR VERY
  DIFFICULT TRAVEL AND BLIZZARD OR NEAR BLIZZARD CONDITIONS.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A WINTER STORM WATCH MEANS THERE IS A POTENTIAL FOR SIGNIFICANT
SNOW...SLEET...OR ICE ACCUMULATIONS THAT MAY IMPACT TRAVEL...IN
THIS CASE SNOW. CONTINUE TO MONITOR THE LATEST FORECASTS. IF
FORECAST CONFIDENCE REGARDING THE STRONG WINDS CONTINUES TO
INCREASE...THIS WATCH MAY BE UPGRADED TO A BLIZZARD WATCH TODAY.

&&

$$

REV
702 
WWUS43 KDMX 181715
WSWDMX

URGENT - WINTER WEATHER MESSAGE
NATIONAL WEATHER SERVICE DES MOINES IA
1115 AM CST TUE DEC 18 2012

...MAJOR WINTER STORM TO AFFECT CENTRAL IOWA WEDNESDAY AND
THURSDAY...

.A STRONG STORM WILL MOVE INTO THE OKLAHOMA PANHANDLE WEDNESDAY
AFTERNOON BEFORE LIFTING NORTHEAST INTO NORTH CENTRAL ILLINOIS BY
THURSDAY. RAIN AND SNOW IS EXPECTED TO OVERSPREAD IOWA WEDNESDAY
BECOMING ALL SNOW WEDNESDAY NIGHT AND ENDING THURSDAY. VERY
STRONG NORTHWEST WINDS WILL PRODUCE CONSIDERABLE BLOWING AND
DRIFTING OF SNOW AND NEAR BLIZZARD CONDITIONS LATE WEDNESDAY
NIGHT INTO THURSDAY RESULTING IN DANGEROUS TRAVEL OVER IOWA.

IAZ025>028-036>039-190115-
/O.NEW.KDMX.WW.Y.0010.121218T1715Z-121218T2200Z/
/O.CON.KDMX.WS.A.0003.121219T1800Z-121221T0000Z/
WRIGHT-FRANKLIN-BUTLER-BREMER-HAMILTON-HARDIN-GRUNDY-BLACK HAWK-
INCLUDING THE CITIES OF...CLARION...HAMPTON...ALLISON...WAVERLY...
WEBSTER CITY...ELDORA...GRUNDY CENTER...WATERLOO
1115 AM CST TUE DEC 18 2012

...WINTER WEATHER ADVISORY IN EFFECT UNTIL 4 PM CST THIS
AFTERNOON...
...WINTER STORM WATCH REMAINS IN EFFECT FROM WEDNESDAY AFTERNOON
THROUGH THURSDAY AFTERNOON...

THE NATIONAL WEATHER SERVICE IN DES MOINES HAS ISSUED A WINTER
WEATHER ADVISORY FOR SNOW AND LIGHT FREEZING RAIN...WHICH IS IN
EFFECT UNTIL 4 PM CST THIS AFTERNOON.

* TIMING OR SHORT TERM TRENDS...LIGHT TO LOCALLY MODERATE SNOW AND
  LIGHT FREEZING RAIN WILL PERSIST AT INTERVALS THROUGH THE MID-
  AFTERNOON HOURS.

* STORM TOTAL SNOW/ICE ACCUMULATIONS...UP TO AN INCH OF ADDITIONAL
  SNOWFALL IS POSSIBLE NORTH TOWARD THE MINNESOTA BORDER. ANY ICE
  ACCUMULATIONS WILL BE VERY LIGHT.

* IMPACTS...THE COMBINATION OF SNOW AND LIGHT ICE WILL MAKE FOR
  VERY SLICK AND HAZARDOUS DRIVING CONDITIONS AT TIMES. 

A WINTER STORM WATCH ALSO REMAINS IN EFFECT FOR THE AREA FROM
WEDNESDAY AFTERNOON INTO THURSDAY.

* TIMING...PRECIPITATION WILL OVERSPREAD CENTRAL IOWA WEDNESDAY 
  AFTERNOON. SNOW IS EXPECTED ALONG AND NORTH OF AN ATLANTIC 
  THROUGH BOONE TO WATERLOO LINE. RAIN IS EXPECTED IN SOUTHERN 
  IOWA SOUTH OF A BEDFORD TO OSKALOOSA LINE. IN BETWEEN...A RAIN 
  AND SNOW MIX IS EXPECTED. THIS PRECIPITATION WILL CHANGE TO 
  ALL SNOW LATE WEDNESDAY EVENING BEFORE ENDING THURSDAY 
  MORNING. 

* STORM TOTAL SNOW ACCUMULATION...5 TO 8 INCHES OF SNOW IS 
  EXPECTED IN THE WATCH AREA. LOCAL AMOUNTS OF UP TO 10 INCHES 
  WILL BE VERY POSSIBLE WITH DRIFTS EVEN HIGHER. 

* WINDS/VISIBILITY...WINDS WILL BECOME VERY STRONG WEDNESDAY 
  NIGHT FROM THE NORTH NORTHWEST. SUSTAINED WINDS OF 25 TO 33 
  MPH ARE EXPECTED WITH GUSTS OVER 45 MPH POSSIBLE. THE 
  STRONGEST WINDS ARE EXPECTED A FEW HOURS PRIOR TO DAYBREAK 
  THROUGH NOON THURSDAY. BLIZZARD OR NEAR BLIZZARD CONDITIONS 
  MAY OCCUR WITH VISIBILITIES REDUCED BELOW ONE QUARTER OF A 
  MILE FROM TIME TO TIME. 

* IMPACTS...VERY DANGEROUS CONDITIONS ARE EXPECTED TO DEVELOP ON 
  WEDNESDAY NIGHT INTO THURSDAY MORNING. BE PREPARED FOR VERY 
  DIFFICULT TRAVEL AND BLIZZARD OR NEAR BLIZZARD CONDITIONS. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A WINTER STORM WATCH MEANS THERE IS A POTENTIAL FOR SIGNIFICANT
SNOW...SLEET...OR ICE ACCUMULATIONS THAT MAY IMPACT TRAVEL...IN
THIS CASE SNOW. CONTINUE TO MONITOR THE LATEST FORECASTS. IF
FORECAST CONFIDENCE REGARDING THE STRONG WINDS CONTINUES TO
INCREASE...THIS WATCH MAY BE UPGRADED TO A BLIZZARD WATCH TODAY.

&&

$$

IAZ005>007-016-017-024-182200-
/O.NEW.KDMX.WW.Y.0010.121218T1715Z-121218T2200Z/
KOSSUTH-WINNEBAGO-WORTH-HANCOCK-CERRO GORDO-HUMBOLDT-
INCLUDING THE CITIES OF...ALGONA...FOREST CITY...NORTHWOOD...
GARNER...MASON CITY...HUMBOLDT
1115 AM CST TUE DEC 18 2012

...WINTER WEATHER ADVISORY IN EFFECT UNTIL 4 PM CST THIS
AFTERNOON...

THE NATIONAL WEATHER SERVICE IN DES MOINES HAS ISSUED A WINTER
WEATHER ADVISORY FOR ...WHICH IS IN EFFECT UNTIL 4 PM CST THIS
AFTERNOON.

* TIMING OR SHORT TERM TRENDS...LIGHT TO LOCALLY MODERATE SNOW AND
  LIGHT FREEZING RAIN WILL PERSIST AT INTERVALS THROUGH THE MID-
  AFTERNOON HOURS.

* STORM TOTAL SNOW/ICE ACCUMULATIONS...UP TO AN INCH OF ADDITIONAL
  SNOWFALL IS POSSIBLE NORTH TOWARD THE MINNESOTA BORDER. ANY ICE
  ACCUMULATIONS WILL BE VERY LIGHT.

* IMPACTS...THE COMBINATION OF SNOW AND LIGHT ICE WILL MAKE FOR
  VERY SLICK AND HAZARDOUS DRIVING CONDITIONS AT TIMES.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A WINTER WEATHER ADVISORY MEANS THAT PERIODS OF SNOW...SLEET...OR
FREEZING RAIN WILL CAUSE TRAVEL DIFFICULTIES. BE PREPARED FOR
SLIPPERY ROADS AND LIMITED VISIBILITY...AND USE CAUTION WHILE
DRIVING.

&&

$$

IAZ033>035-044>050-057>062-070>075-081>086-092>097-190115-
/O.CON.KDMX.WS.A.0003.121219T1800Z-121221T0000Z/
SAC-CALHOUN-WEBSTER-CRAWFORD-CARROLL-GREENE-BOONE-STORY-MARSHALL-
TAMA-AUDUBON-GUTHRIE-DALLAS-POLK-JASPER-POWESHIEK-CASS-ADAIR-
MADISON-WARREN-MARION-MAHASKA-ADAMS-UNION-CLARKE-LUCAS-MONROE-
WAPELLO-TAYLOR-RINGGOLD-DECATUR-WAYNE-APPANOOSE-DAVIS-
INCLUDING THE CITIES OF...SAC CITY...ROCKWELL CITY...FORT DODGE...
DENISON...CARROLL...JEFFERSON...BOONE...AMES...MARSHALLTOWN...
TOLEDO...AUDUBON...GUTHRIE CENTER...ADEL...DES MOINES...NEWTON...
GRINNELL...ATLANTIC...GREENFIELD...WINTERSET...INDIANOLA...
KNOXVILLE...OSKALOOSA...CORNING...CRESTON...OSCEOLA...CHARITON...
ALBIA...OTTUMWA...BEDFORD...MOUNT AYR...LEON...CORYDON...
CENTERVILLE...BLOOMFIELD
1115 AM CST TUE DEC 18 2012

...WINTER STORM WATCH REMAINS IN EFFECT FROM WEDNESDAY AFTERNOON
THROUGH THURSDAY AFTERNOON...

* TIMING...PRECIPITATION WILL OVERSPREAD CENTRAL IOWA WEDNESDAY 
  AFTERNOON. SNOW IS EXPECTED ALONG AND NORTH OF AN ATLANTIC 
  THROUGH BOONE TO WATERLOO LINE. RAIN IS EXPECTED IN SOUTHERN 
  IOWA SOUTH OF A BEDFORD TO OSKALOOSA LINE. IN BETWEEN...A RAIN 
  AND SNOW MIX IS EXPECTED. THIS PRECIPITATION WILL CHANGE TO 
  ALL SNOW LATE WEDNESDAY EVENING BEFORE ENDING THURSDAY 
  MORNING. 

* STORM TOTAL SNOW ACCUMULATION...5 TO 8 INCHES OF SNOW IS 
  EXPECTED IN THE WATCH AREA. LOCAL AMOUNTS OF UP TO 10 INCHES 
  WILL BE VERY POSSIBLE WITH DRIFTS EVEN HIGHER. 

* WINDS/VISIBILITY...WINDS WILL BECOME VERY STRONG WEDNESDAY 
  NIGHT FROM THE NORTH NORTHWEST. SUSTAINED WINDS OF 25 TO 33 
  MPH ARE EXPECTED WITH GUSTS OVER 45 MPH POSSIBLE. THE 
  STRONGEST WINDS ARE EXPECTED A FEW HOURS PRIOR TO DAYBREAK 
  THROUGH NOON THURSDAY. BLIZZARD OR NEAR BLIZZARD CONDITIONS 
  MAY OCCUR WITH VISIBILITIES REDUCED BELOW ONE QUARTER OF A 
  MILE FROM TIME TO TIME. 

* IMPACTS...VERY DANGEROUS CONDITIONS ARE EXPECTED TO DEVELOP ON 
  WEDNESDAY NIGHT INTO THURSDAY MORNING. BE PREPARED FOR VERY 
  DIFFICULT TRAVEL AND BLIZZARD OR NEAR BLIZZARD CONDITIONS. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A WINTER STORM WATCH MEANS THERE IS A POTENTIAL FOR SIGNIFICANT
SNOW...SLEET...OR ICE ACCUMULATIONS THAT MAY IMPACT TRAVEL...IN
THIS CASE SNOW. CONTINUE TO MONITOR THE LATEST FORECASTS. IF
FORECAST CONFIDENCE REGARDING THE STRONG WINDS CONTINUES TO
INCREASE...THIS WATCH MAY BE UPGRADED TO A BLIZZARD WATCH TODAY.

&&

$$

LEE
528 
WWUS43 KDMX 182124
WSWDMX

URGENT - WINTER WEATHER MESSAGE
NATIONAL WEATHER SERVICE DES MOINES IA
324 PM CST TUE DEC 18 2012

...DANGEROUS WINTER STORM TO AFFECT CENTRAL IOWA LATE WEDNESDAY
INTO THURSDAY...

.A STRONG STORM WILL MOVE INTO THE OKLAHOMA PANHANDLE WEDNESDAY
AFTERNOON BEFORE LIFTING NORTHEAST INTO NORTH CENTRAL ILLINOIS BY
THURSDAY MORNING. RAIN AND SNOW IS EXPECTED TO OVERSPREAD IOWA
WEDNESDAY AFTERNOON BECOMING ALL SNOW WEDNESDAY NIGHT AND ENDING
THURSDAY. VERY STRONG NORTHWEST WINDS WILL PRODUCE CONSIDERABLE
BLOWING AND DRIFTING OF SNOW AND NEAR BLIZZARD CONDITIONS LATE
WEDNESDAY NIGHT INTO THURSDAY RESULTING IN DANGEROUS TRAVEL OVER
IOWA.

IAZ025>028-036>039-190500-
/O.CAN.KDMX.WW.Y.0010.000000T0000Z-121218T2200Z/
/O.UPG.KDMX.WS.A.0003.121219T1800Z-121221T0000Z/
/O.NEW.KDMX.WS.W.0004.121220T0000Z-121221T0000Z/
WRIGHT-FRANKLIN-BUTLER-BREMER-HAMILTON-HARDIN-GRUNDY-BLACK HAWK-
INCLUDING THE CITIES OF...CLARION...HAMPTON...ALLISON...WAVERLY...
WEBSTER CITY...ELDORA...GRUNDY CENTER...WATERLOO
324 PM CST TUE DEC 18 2012

...WINTER STORM WARNING IN EFFECT FROM 6 PM WEDNESDAY TO 6 PM CST
THURSDAY...
...WINTER WEATHER ADVISORY IS CANCELLED...

THE NATIONAL WEATHER SERVICE IN DES MOINES HAS ISSUED A WINTER
STORM WARNING FOR HEAVY SNOW AND BLOWING SNOW...WHICH IS IN EFFECT
FROM 6 PM WEDNESDAY TO 6 PM CST THURSDAY. THE WINTER WEATHER
ADVISORY HAS BEEN CANCELLED. THE WINTER STORM WATCH IS NO LONGER
IN EFFECT.

* TIMING...SNOW WILL OVERSPREAD THE AREA LATE WEDNESDAY AFTERNOON
  INTO THE EVENING. THE SNOW MAY INITIALLY BEGIN AS A MIXTURE OF
  RAIN AND SNOW BUT WILL TRANSITION TO ALL SNOW QUICKLY. THE SNOW
  WILL PERSIST WEDNESDAY NIGHT...HEAVY AT TIMES...WITH THE SNOW
  TAPERING OF ON THURSDAY MORNING.

* STORM TOTAL SNOW ACCUMULATION...STORM TOTAL SNOWFALL OF 7 TO 11
  INCHES IS POSSIBLE WITH LOCALLY HEAVIER AMOUNTS. SNOW DRIFTS
  SEVERAL FEET HIGH WILL BE POSSIBLE DUE TO THE VERY STRONG WINDS.

* WINDS/VISIBILITY...WINDS WILL BECOME VERY STRONG WEDNESDAY NIGHT
  FROM THE NORTH NORTHWEST. SUSTAINED WINDS OF 25 TO 30 MPH ARE
  EXPECTED WITH GUSTS OVER 45 MPH POSSIBLE. THE STRONGEST WINDS
  ARE EXPECTED A FEW HOURS PRIOR TO DAYBREAK THROUGH NOON
  THURSDAY. NEAR BLIZZARD CONDITIONS MAY OCCUR WITH VISIBILITIES
  REDUCED BELOW ONE QUARTER OF A MILE FROM TIME TO TIME.

* IMPACTS...VERY DANGEROUS CONDITIONS ARE EXPECTED TO DEVELOP ON
  WEDNESDAY NIGHT INTO THURSDAY MORNING. BE PREPARED FOR VERY
  DIFFICULT TRAVEL AND NEAR BLIZZARD CONDITIONS. THIS WARNING MAY
  NEED TO BE UPGRADED TO A BLIZZARD WARNING SHOULD FORECAST CONDITIONS
  WARRANT.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A WINTER STORM WARNING FOR HEAVY SNOW MEANS SEVERE WINTER WEATHER
CONDITIONS ARE EXPECTED OR OCCURRING. SIGNIFICANT AMOUNTS OF SNOW
ARE FORECAST THAT WILL MAKE TRAVEL DANGEROUS. ONLY TRAVEL IN AN
EMERGENCY. IF YOU MUST TRAVEL...KEEP AN EXTRA FLASHLIGHT...
FOOD...AND WATER IN YOUR VEHICLE IN CASE OF AN EMERGENCY. 

&&

$$

IAZ005>007-016-017-024-190500-
/O.CAN.KDMX.WW.Y.0010.000000T0000Z-121218T2200Z/
/O.NEW.KDMX.WS.A.0004.121220T0000Z-121221T0000Z/
KOSSUTH-WINNEBAGO-WORTH-HANCOCK-CERRO GORDO-HUMBOLDT-
INCLUDING THE CITIES OF...ALGONA...FOREST CITY...NORTHWOOD...
GARNER...MASON CITY...HUMBOLDT
324 PM CST TUE DEC 18 2012

...WINTER STORM WATCH IN EFFECT FROM WEDNESDAY EVENING THROUGH
THURSDAY AFTERNOON...
...WINTER WEATHER ADVISORY IS CANCELLED...

THE NATIONAL WEATHER SERVICE IN DES MOINES HAS ISSUED A WINTER
STORM WATCH...WHICH IS IN EFFECT FROM WEDNESDAY EVENING THROUGH
THURSDAY AFTERNOON. THE WINTER WEATHER ADVISORY HAS BEEN
CANCELLED. 

* TIMING...SNOW IS EXPECTED TO OVERSPREAD THE AREA ON LATE
  WEDNESDAY AFTERNOON AND PERSIST WEDNESDAY NIGHT BEFORE ENDING. 

* STORM TOTAL SNOW/ICE ACCUMULATIONS...2 TO 5 INCHES OF SNOW WITH
  LOCALLY HEAVIER AMOUNTS WILL BE POSSIBLE.  

* WINDS/VISIBILITY...WINDS WILL INCREASE FROM THE NORTH NORTHWEST
  ON WEDNESDAY NIGHT AT 20 TO 30 MPH WITH HIGHER GUSTS. NEAR
  BLIZZARD CONDITIONS WILL BE POSSIBLE LATE WEDNESDAY NIGHT INTO
  THURSDAY WITH CONSIDERABLE BLOWING SNOW.

* IMPACTS...HAZARDOUS CONDITIONS ARE EXPECTED TO DEVELOP ON
  WEDNESDAY NIGHT INTO THURSDAY MORNING. BE PREPARED FOR NEAR
  BLIZZARD CONDITIONS. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A WINTER STORM WATCH MEANS THERE IS A POTENTIAL FOR SIGNIFICANT
SNOW...SLEET...OR ICE ACCUMULATIONS THAT MAY IMPACT TRAVEL.
CONTINUE TO MONITOR THE LATEST FORECASTS.

&&

$$

IAZ033>035-044>047-057>059-070>072-081-082-092-093-190500-
/O.UPG.KDMX.WS.A.0003.121219T1800Z-121221T0000Z/
/O.NEW.KDMX.WS.W.0004.121219T2200Z-121220T1800Z/
SAC-CALHOUN-WEBSTER-CRAWFORD-CARROLL-GREENE-BOONE-AUDUBON-GUTHRIE-
DALLAS-CASS-ADAIR-MADISON-ADAMS-UNION-TAYLOR-RINGGOLD-
INCLUDING THE CITIES OF...SAC CITY...ROCKWELL CITY...FORT DODGE...
DENISON...CARROLL...JEFFERSON...BOONE...AUDUBON...
GUTHRIE CENTER...ADEL...ATLANTIC...GREENFIELD...WINTERSET...
CORNING...CRESTON...BEDFORD...MOUNT AYR
324 PM CST TUE DEC 18 2012

...WINTER STORM WARNING IN EFFECT FROM 4 PM WEDNESDAY TO NOON CST
THURSDAY...

THE NATIONAL WEATHER SERVICE IN DES MOINES HAS ISSUED A WINTER
STORM WARNING FOR HEAVY SNOW AND BLOWING SNOW...WHICH IS IN EFFECT
FROM 4 PM WEDNESDAY TO NOON CST THURSDAY. THE WINTER STORM WATCH
IS NO LONGER IN EFFECT.

* TIMING...PRECIPITATION WILL OVERSPREAD CENTRAL IOWA LATE
  WEDNESDAY AFTERNOON. SNOW IS EXPECTED ALONG AND NORTH OF AN
  ATLANTIC THROUGH JEFFERSON LINE. RAIN IS EXPECTED IN SOUTHERN
  IOWA SOUTH OF A BEDFORD TO OSCEOLA LINE. IN BETWEEN...A RAIN AND
  SNOW MIX IS EXPECTED. THIS PRECIPITATION WILL CHANGE TO ALL SNOW
  LATE WEDNESDAY EVENING BEFORE ENDING ON THURSDAY MORNING.

* STORM TOTAL SNOW ACCUMULATION...6 TO 10 INCHES OF SNOW IS
  EXPECTED BY THURSDAY MORNING. THE HEAVIEST SNOW AXIS WILL BE
  ALONG A LINE FROM ATLANTIC TO ADEL. THE LOWEST AMOUNTS ARE
  EXPECTED NEAR THE MISSOURI BORDER. SNOW DRIFTS SEVERAL FEET DEEP
  WILL BE POSSIBLE GIVEN THE STRONG WINDS.

* WINDS/VISIBILITY...WINDS WILL BECOME VERY STRONG WEDNESDAY NIGHT
  FROM THE NORTH NORTHWEST. SUSTAINED WINDS OF 25 TO 35 MPH ARE
  EXPECTED WITH GUSTS OVER 45 MPH POSSIBLE. THE STRONGEST WINDS
  ARE EXPECTED A FEW HOURS PRIOR TO DAYBREAK THROUGH NOON
  THURSDAY. NEAR BLIZZARD CONDITIONS MAY OCCUR WITH VISIBILITIES
  REDUCED BELOW ONE QUARTER OF A MILE FROM TIME TO TIME.

* IMPACTS...VERY DANGEROUS CONDITIONS ARE EXPECTED TO DEVELOP ON
  WEDNESDAY NIGHT INTO THURSDAY MORNING. BE PREPARED FOR VERY
  DIFFICULT TRAVEL AND NEAR BLIZZARD CONDITIONS. THIS WARNING MAY
  NEED TO BE UPGRADED TO A BLIZZARD WARNING SHOULD FORECAST CONDITIONS
  WARRANT.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A WINTER STORM WARNING FOR HEAVY SNOW MEANS SEVERE WINTER WEATHER
CONDITIONS ARE EXPECTED OR OCCURRING.  SIGNIFICANT AMOUNTS OF SNOW
ARE FORECAST THAT WILL MAKE TRAVEL DANGEROUS. ONLY TRAVEL IN AN
EMERGENCY. IF YOU MUST TRAVEL...KEEP AN EXTRA FLASHLIGHT...
FOOD...AND WATER IN YOUR VEHICLE IN CASE OF AN EMERGENCY.

&&

$$

IAZ048>050-060>062-073>075-083>086-094>097-190500-
/O.UPG.KDMX.WS.A.0003.121219T1800Z-121221T0000Z/
/O.NEW.KDMX.WS.W.0004.121220T0000Z-121221T0000Z/
STORY-MARSHALL-TAMA-POLK-JASPER-POWESHIEK-WARREN-MARION-MAHASKA-
CLARKE-LUCAS-MONROE-WAPELLO-DECATUR-WAYNE-APPANOOSE-DAVIS-
INCLUDING THE CITIES OF...AMES...MARSHALLTOWN...TOLEDO...
DES MOINES...NEWTON...GRINNELL...INDIANOLA...KNOXVILLE...
OSKALOOSA...OSCEOLA...CHARITON...ALBIA...OTTUMWA...LEON...
CORYDON...CENTERVILLE...BLOOMFIELD
324 PM CST TUE DEC 18 2012

...WINTER STORM WARNING IN EFFECT FROM 6 PM WEDNESDAY TO 6 PM CST
THURSDAY...

THE NATIONAL WEATHER SERVICE IN DES MOINES HAS ISSUED A WINTER
STORM WARNING FOR HEAVY SNOW AND BLOWING SNOW...WHICH IS IN EFFECT
FROM 6 PM WEDNESDAY TO 6 PM CST THURSDAY. THE WINTER STORM WATCH
IS NO LONGER IN EFFECT.

* TIMING...PRECIPITATION WILL OVERSPREAD CENTRAL IOWA BY EARLY
  WEDNESDAY EVENING. SNOW IS EXPECTED ALONG AND NORTH OF A BOONE
  TO WATERLOO LINE. RAIN IS EXPECTED IN SOUTHERN IOWA SOUTH OF AN
  OSCEOLA TO OSKALOOSA LINE. IN BETWEEN...A RAIN AND SNOW MIX IS
  EXPECTED. THIS PRECIPITATION WILL CHANGE TO ALL SNOW LATE
  WEDNESDAY EVENING BEFORE ENDING ON THURSDAY MORNING.

* STORM TOTAL SNOW ACCUMULATION...6 TO 12 INCHES OF SNOW IS
  EXPECTED BY THURSDAY MORNING. THE HEAVIEST SNOW AXIS WILL BE
  ALONG A LINE FROM DES MOINES TO TAMA. THE LOWEST AMOUNTS ARE
  EXPECTED NEAR THE MISSOURI BORDER. SNOW DRIFTS SEVERAL FEET DEEP
  WILL BE POSSIBLE GIVEN THE STRONG WINDS.

* WINDS/VISIBILITY...WINDS WILL BECOME VERY STRONG WEDNESDAY NIGHT
  FROM THE NORTH NORTHWEST. SUSTAINED WINDS OF 25 TO 35 MPH ARE
  EXPECTED WITH GUSTS OVER 45 MPH POSSIBLE. THE STRONGEST WINDS
  ARE EXPECTED A FEW HOURS PRIOR TO DAYBREAK THROUGH NOON
  THURSDAY. NEAR BLIZZARD CONDITIONS MAY OCCUR WITH VISIBILITIES
  REDUCED BELOW ONE QUARTER OF A MILE FROM TIME TO TIME.

* IMPACTS...VERY DANGEROUS CONDITIONS ARE EXPECTED TO DEVELOP ON
  WEDNESDAY NIGHT INTO THURSDAY MORNING. BE PREPARED FOR VERY
  DIFFICULT TRAVEL AND NEAR BLIZZARD CONDITIONS. THIS WARNING MAY
  NEED TO BE UPGRADED TO A BLIZZARD WARNING SHOULD FORECAST CONDITIONS
  WARRANT.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A WINTER STORM WARNING FOR HEAVY SNOW MEANS SEVERE WINTER WEATHER
CONDITIONS ARE EXPECTED OR OCCURRING.  SIGNIFICANT AMOUNTS OF SNOW
ARE FORECAST THAT WILL MAKE TRAVEL DANGEROUS. ONLY TRAVEL IN AN
EMERGENCY. IF YOU MUST TRAVEL...KEEP AN EXTRA
FLASHLIGHT...FOOD...AND WATER IN YOUR VEHICLE IN CASE OF AN
EMERGENCY.

&&

$$

IAZ004-015-023-190500-
/O.NEW.KDMX.WS.A.0004.121220T0000Z-121221T0000Z/
EMMET-PALO ALTO-POCAHONTAS-
INCLUDING THE CITIES OF...ESTHERVILLE...EMMETSBURG...POCAHONTAS
324 PM CST TUE DEC 18 2012

...WINTER STORM WATCH IN EFFECT FROM WEDNESDAY EVENING THROUGH
THURSDAY AFTERNOON...

THE NATIONAL WEATHER SERVICE IN DES MOINES HAS ISSUED A WINTER
STORM WATCH...WHICH IS IN EFFECT FROM WEDNESDAY EVENING THROUGH
THURSDAY AFTERNOON. 

* TIMING...SNOW IS EXPECTED TO OVERSPREAD THE AREA ON LATE
  WEDNESDAY AFTERNOON AND PERSIST WEDNESDAY NIGHT BEFORE ENDING. 

* STORM TOTAL SNOW/ICE ACCUMULATIONS...2 TO 5 INCHES OF SNOW WITH
  LOCALLY HEAVIER AMOUNTS WILL BE POSSIBLE.  

* WINDS/VISIBILITY...WINDS WILL INCREASE FROM THE NORTH NORTHWEST
  ON WEDNESDAY NIGHT AT 20 TO 30 MPH WITH HIGHER GUSTS. NEAR
  BLIZZARD CONDITIONS WILL BE POSSIBLE LATE WEDNESDAY NIGHT INTO
  THURSDAY WITH CONSIDERABLE BLOWING SNOW.

* IMPACTS...HAZARDOUS CONDITIONS ARE EXPECTED TO DEVELOP ON
  WEDNESDAY NIGHT INTO THURSDAY MORNING. BE PREPARED FOR NEAR
  BLIZZARD CONDITIONS.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A WINTER STORM WATCH MEANS THERE IS A POTENTIAL FOR SIGNIFICANT
SNOW...SLEET...OR ICE ACCUMULATIONS THAT MAY IMPACT TRAVEL.
CONTINUE TO MONITOR THE LATEST FORECASTS.

&&

$$

CC

What forecasters said that day

The local office's own words before this winter storm watch went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS Des Moines, IA wrote its last area forecast discussion before this winter storm watch went out at Dec 17, 4:00 PM CST, 1 minute earlier.

Area forecast discussion, Dec 17, 4:00 PM CST, 1 minute before
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DES MOINES IA
400 PM CST MON DEC 17 2012

...SIGNIFICANT WINTER STORM TO IMPACT THE MIDWEST AND PLAINS
WEDNESDAY AND THURSDAY...

.SHORT TERM /TONIGHT/...
LOW PRESSURE OVER NORTHEAST WYOMING WILL SHIFT EAST ACROSS SOUTH
DAKOTA AND NEBRASKA AND REACH NORTHWEST IOWA LATE TONIGHT. AN
ASSOCIATED UPPER LEVEL SHORT WILL SPREAD INCREASING QG FORCING
ACROSS CENTRAL IOWA. IN ADDITION...STRONG THETA-E ADVECTION WILL
ARRIVE AFTER MIDNIGHT THROUGH CENTRAL AND NORTHWEST IOWA. THE BEST
COMBINATION OF FORCING IS OVER CENTRAL IA NEAR DES MOINES AND AMES
BETWEEN 3 AM TO 6 AM HOWEVER THE DEEPER MOISTURE WILL BE FARTHER
NORTH. TYPICALLY THIS TIME OF YEAR FORCING TRUMPS DEEP MOISTURE
THEREFORE CERTAINLY SHOULD HAVE PRECIPITATION FARTHER SOUTH THAN
WHAT MOST MODEL GUIDANCE PRECIPITATION FIELDS WOULD SUGGEST. WARM
ADVECTION IN THE LOW LEVELS IS EXPECTED AS WELL OVERNIGHT RESULTING
IN NON-DIURNAL TEMPERATURES. THIS COULD SWITCH PRECIPITATION TYPE TO
RAIN ON THE SOUTHERN FRINGES. NOT CONFIDENT IN POTENTIAL OF FREEZING
RAIN WITH UNCERTAINTY IN ARRIVAL OF WARMER AIR ALOFT...THOUGH CAN
NOT TOTALLY DISCOUNT. POTENTIAL AS WELL FOR POCKETS OF LOWER
VISIBILITIES DUE TO FOG THOUGH LOW LEVEL WARM ADVECTION SHOULD LIMIT
AREAL COVERAGE OF VISIBILITIES BELOW 2SM.

.LONG TERM /TUESDAY THROUGH MONDAY/...
WILL SEE SOME LINGERING POPS IN THE NORTH ON TUESDAY MORNING AS THE
SYSTEM GRADUALLY DEPARTS TO THE EAST.  SOME LIGHT ACCUMULATIONS WILL
STILL BE POSSIBLE AROUND MASON CITY BEFORE MIDDAY BUT PCPN IS
EXPECTED TO END BY MIDDAY. THE WEATHER WILL BE TRANQUIL FROM TUESDAY
AFTERNOON INTO EARLY WEDNESDAY MORNING BEFORE MAJOR SYSTEM BEGINS TO
AFFECT THE FORECAST AREA.

THIS MAJOR STORM IS CURRENTLY OFF THE WEST COAST AND WILL COME
ASHORE LATE TONIGHT INTO TUESDAY.  THEREFORE...THERE IS LITTLE
RESOLUTION OF THE SYSTEM BY THE UPPER AIR NETWORK WHICH IS LIKELY
CAUSING SOME OF THE DIFFERENCES SEEN IN THE MODEL RUNS.  INITIALLY
ON WEDNESDAY...RIDGE AXIS WILL BE IN PLACE ACROSS THE NORTHEAST WITH
RELATIVELY QUITE WEATHER.  HOWEVER...BY MIDDAY...FORCING WILL
RAPIDLY INCREASE AS ISENTROPIC LIFT BEGINS IN EARNEST.  STRONG
FRONTOGENETICAL FORCING ALSO ARRIVES ACROSS CENTRAL INTO NORTHERN
IOWA BY LATE AFTERNOON WHICH WILL LIKELY ENHANCE PCPN RATES IN THOSE
LOCATIONS.  PCPN WILL BREAK OUT DURING THE AFTERNOON AND INCREASE IN
BOTH COVERAGE AND INTENSITY AS THE AFTERNOON PROGRESSES.  SNOW IS
EXPECTED ALONG AND NORTH OF AN ATLANTIC TO WATERLOO LINE WITH A BAND
OF MIXED PCPN OF 50 MILES WIDE OR SO SOUTH OF THE SNOW.  RAIN IS
EXPECTED ALONG THE MISSOURI BORDER AS READINGS REMAIN ABOVE
FREEZING.

CONDITIONS DETERIORATE RAPIDLY ON WEDNESDAY NIGHT AS COLD ADVECTION
INTENSIFIES ACROSS THE STATE.  UPPER SYSTEM WILL EJECT FROM SOUTHERN
PLAINS AND RACE NORTHEAST TO NEAR QUINCY ILLINOIS BY DAYBREAK.
SYSTEM WILL BE DEEPENING AND BECOMING NEGATIVELY TILTED WITH TIME AS
SURFACE LOW STRENGTHENS.  PCPN ACRS THE FORECAST AREA WILL BECOME
ALL SNOW BY MIDNIGHT AS COLD AIR IS DRAWN SOUTHWARD.  WINDS ARE
LIKELY TO BECOME A VERY SERIOUS ISSUE AFTER MIDNIGHT AND CERTAINLY
BY DAYBREAK ON THURSDAY.  925MB WINDS WILL BE NEAR OR EVEN SLIGHTLY
ABOVE 50KTS WITH MOS OUTPUT SHOWING SUSTAINED WINDS OF 30KTS IN MANY
LOCATIONS IN CENTRAL IOWA.  THIS EVENT MAY BECOME MORE OF A BLIZZARD
INTO THURSDAY MORNING AS THE WINDS INCREASE AND WILL HAVE TO BE
MONITORED CLOSELY. SNOW ON WEDNESDAY NIGHT WILL BE HEAVIEST IN THE
EVENING AS MID LEVEL FORCING IS MAXIMIZED.  SOME CONVECTIVE SNOW
WILL BE POSSIBLE AS WELL WITH NEGATIVE EPV ACROSS MUCH OF THE STATE
WITH DECENT MID LEVEL LAPSE RATES.  CONDITIONS WILL BE POOR ON
THURSDAY MORNING WITH VERY STRONG WINDS DESPITE THE SNOWFALL
ENDING.  GIVEN ALL OF THIS...HAVE ISSUED A WINTER STORM WATCH FOR
MUCH OF CENTRAL IOWA FROM MIDDAY WEDNESDAY INTO THURSDAY FOR THE
POTENTIAL OF HEAVY SNOWFALL AND VERY STRONG WINDS. AN UPGRADE TO
BLIZZARD WATCH MAY BE NEEDED SHOULD FORECAST WINDS REMAIN STRONG OR
INCREASE.

THE WEATHER BEYOND THURSDAY IS RELATIVELY QUIET WITH LITTLE CHANGE
IN THE FORECAST.  MAIN CONCERN IS THAT TEMPERATURES WOULD BE TOO
WARM GIVEN THE FRESH SNOW COVER ACROSS THE AREA.

&&

.AVIATION...17/18Z
LOW STRATUS WILL PREVAIL THROUGH MUCH OF THE PERIOD. POSSIBLE BRIEF
BREAKS THIS AFTERNOON HOWEVER STRATUS DECK DROPPING THROUGH WRN MN
AND EASTERN SD AND EASTERN NEBRASKA WILL ROTATE INTO CNTRL IA LATER
THIS AFTERNOON AND TONIGHT. MVFR FOG POSSIBLE THROUGH THE REMAINDER
OF THE DAY ESPECIALLY NEAR THE IFR STRATUS. POSSIBLE IT COULD GO
MUCH LOWER TONIGHT HOWEVER AT THIS TIME THE FOCUS IS ON CIGS. A
BOUNDARY WILL MOVE THROUGH TUE MORNING WITH A SWITCH TO BREEZY
WESTERLY WINDS AND GRADUALLY IMPROVING CONDITIONS.

&&

.DMX WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WATCH FROM WEDNESDAY AFTERNOON THROUGH THURSDAY
AFTERNOON FOR ADAIR-ADAMS-APPANOOSE-AUDUBON-BLACK HAWK-BOONE-
BREMER-BUTLER-CALHOUN-CARROLL-CASS-CLARKE-CRAWFORD-DALLAS-DAVIS-
DECATUR-FRANKLIN-GREENE-GRUNDY-GUTHRIE-HAMILTON-HARDIN-JASPER-LUCAS-
MADISON-MAHASKA-MARION-MARSHALL-MONROE-POLK-POWESHIEK-RINGGOLD-
SAC-STORY-TAMA-TAYLOR-UNION-WAPELLO-WARREN-WAYNE-WEBSTER-WRIGHT.

&&

SHORT TERM...DONAVON
LONG TERM...COGIL
AVIATION...DONAVON
Hazardous weather outlook, Dec 17, 4:01 PM CST, 0 minutes before
HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE DES MOINES IA
401 PM CST MON DEC 17 2012

IAZ025>028-033>039-044>050-057>062-070>075-081>086-092>097-182215-
WRIGHT-FRANKLIN-BUTLER-BREMER-SAC-CALHOUN-WEBSTER-HAMILTON-HARDIN-
GRUNDY-BLACK HAWK-CRAWFORD-CARROLL-GREENE-BOONE-STORY-MARSHALL-TAMA-
AUDUBON-GUTHRIE-DALLAS-POLK-JASPER-POWESHIEK-CASS-ADAIR-MADISON-
WARREN-MARION-MAHASKA-ADAMS-UNION-CLARKE-LUCAS-MONROE-WAPELLO-TAYLOR-
RINGGOLD-DECATUR-WAYNE-APPANOOSE-DAVIS-
401 PM CST MON DEC 17 2012

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF CENTRAL AND
SOUTH CENTRAL IOWA.

.DAY ONE...THIS AFTERNOON AND TONIGHT

NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

.DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY

A WINTER STORM WATCH IS IN EFFECT FOR THE AREA. PLEASE REFER TO
THE NATIONAL WEATHER SERVICE WEBSITE AT WEATHER.GOV/DESMOINES FOR
FURTHER DETAILS.

.SPOTTER INFORMATION STATEMENT...
SPOTTER ACTIVATION IS NOT EXPECTED HOWEVER SNOWFALL AND BLOWING
SNOW REPORTS WOULD BE APPRECIATED WEDNESDAY AFTERNOON THROUGH THURSDAY.

IAZ004>007-015>017-023-024-182215-
EMMET-KOSSUTH-WINNEBAGO-WORTH-PALO ALTO-HANCOCK-CERRO GORDO-
POCAHONTAS-HUMBOLDT-
401 PM CST MON DEC 17 2012

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF NORTH CENTRAL
IOWA.

.DAY ONE...THIS AFTERNOON AND TONIGHT

NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

.DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY

LIGHT TO MODERATE ACCUMULATIONS OF SNOWFALL ARE POSSIBLE WEDNESDAY
AFTERNOON AND WEDNESDAY NIGHT. IN ADDITION...STRONG NORTHWEST
WINDS WILL DEVELOP WEDNESDAY NIGHT AND CREATE THE POTENTIAL FOR
BLOWING AND DRIFTING OF SNOW THROUGH THURSDAY.

.SPOTTER INFORMATION STATEMENT...
SPOTTER ACTIVATION IS NOT EXPECTED HOWEVER SNOWFALL AND BLOWING
SNOW REPORTS WOULD BE APPRECIATED WEDNESDAY AFTERNOON THROUGH THURSDAY.

Nearby

Winter Storm Watches in Iowa, 2012Every winter storm watch in 2012

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.