(Source: Severe Storms Predication Center/Norman, OK 3:28-A.M. cst)

AREAS AFFECTED…Eastern NE & Western IA

CONCERNING…HEAVY SNOW….

INCH AN HOUR SNOWFALL RATES /GREATER IN THUNDERSNOW/ WILL GRADUALLY TAPER OFF LATER THIS MORNING. CESSATION OF HEAVIER RATES IS ALREADY ONGOING ACROSS CENTRAL NEB.  HEAVY SNOWFALL HAS DEVELOPED IN THE FAVORED LEFT EXIT REGION OF A MID-UPPER LEVEL JET…NOW QUICKLY PROGRESSING NORTHEASTWARD.

WITH THE LESSENING OF MORE SUPPORTIVE VERTICAL MOTION…RATES SHOULD GRADUALLY BEGIN TO TAPER OFF THIS MORNING. UNTIL THEN…WEAK MID-LEVEL INSTABILITY HAS SUPPORTED THE OCCASIONAL LIGHTNING STRIKE ACROSS SOUTHERN NEB. THIS AREA OF ENHANCED CONVECTIVE SNOWFALL POTENTIAL WILL SHIFT INTO SOUTHERN IA OVER THE NEXT FEW HOURS. BRIEF BURSTS OF HEAVIER SNOW REMAIN POSSIBLE IN THUNDERSNOW.

A Winter Weather Advisory remains in effect until Midnight for Fremont & Page Counties, where 1-3 inches of snow are expected.

WINTER STORM WARNING…

MONONA-HARRISON-SHELBY-POTTAWATTAMIE-MILLS-MONTGOMERY COUNTIES...

…WINTER STORM WARNING REMAINS IN EFFECT UNTIL MIDNIGHT CST TONIGHT…

* TIMING…SNOW WILL CONTINUE THROUGH MUCH OF DAY. THE HEAVIEST SNOWFALL WILL OCCUR THROUGH THE LATE MORNING HOURS WITH SNOW TAPERING OFF BY LATE AFTERNOON. * ACCUMULATIONS…A BAND OF SNOW ACCUMULATIONS OF 6 TO 11 INCHES IS EXPECTED TO EXTEND FROM SOUTH CENTRAL NEBRASKA ROUGHLY ALONG AND NORTH OF THE INTERSTATE 80 CORRIDOR AND INTO WEST CENTRAL IOWA. LOCALLY HIGHER AMOUNTS UP TO OVER A FOOT ARE POSSIBLE WITHIN THAT BAND OF HEAVY SNOW. * IMPACTS…TRAVEL WILL BE VERY DIFFICULT THROUGH THE DAY DUE TO HEAVY WET SNOW AND SOME BLOWING SNOW IS POSSIBLE. THE COMBINATION OF SNOWFALL AND WINDS OF 15 TO 30 MPH WILL REDUCE VISIBILITIES TO A HALF MILE OR LESS AT TIMES.

URGENT – WINTER WEATHER MESSAGE

NATIONAL WEATHER SERVICE DES MOINES IA

905 PM CST FRI FEB 3 2012

…HEAVY SNOW EXPECTED ACROSS PORTIONS OF CENTRAL TO SOUTHWEST IOWA BEGINNING OVERNIGHT AND CONTINUING THROUGH SATURDAY…

A STRONG UPPER LEVEL STORM SYSTEM WILL CONTINUE TO TRACK INTO THE MIDWEST TONIGHT. RAIN WILL MIX WITH AND EVENTUALLY CHANGE OVER TO SNOW OVERNIGHT AND INTO EARLY SATURDAY MORNING. A MODERATE TO LOCALLY HEAVY BAND OF SNOW WILL SET UP FROM CENTRAL TO WEST CENTRAL IA

CRAWFORD-CARROLL-GREENE-BOONE-STORY-AUDUBON-GUTHRIE-DALLAS-POLK-CASS-ADAIR-MADISON-ADAMS-UNION-INCLUDING THE CITIES OF…DENISON…CARROLL…JEFFERSON…BOONE…AMES…AUDUBON…GUTHRIE CENTER…ADEL…DES MOINES…ATLANTIC…GREENFIELD…WINTERSET…CORNING…CRESTON

905 PM CST FRI FEB 3 2012

…WINTER STORM WARNING REMAINS IN EFFECT FROM MIDNIGHT TONIGHT TO 6 AM CST SUNDAY…

* TIMING…A GRADUAL TRANSITION FROM RAIN TO SNOW WILL BEGIN LATE THIS DURING THE OVERNIGHT HOURS. MUCH OF THE WARNED AREA WILL SEE ALL SNOW BY SATURDAY MORNING. A NARROW BAND OF HEAVY SNOW IS EXPECTED TO SET UP ACROSS CENTRAL IOWA DURING THE DAY ON SATURDAY. SNOW WILL BEGIN TO DIMINISH SATURDAY EVENING.

* STORM TOTAL SNOW…SNOWFALL AMOUNTS FROM 4 TO 8 INCHES WITH LOCALLY HEAVIER AMOUNTS ARE POSSIBLE. HEAVIEST TOTALS ARE EXPECTED OVER THE WESTERN PORTION OF THE WARNED AREA.

* WINDS/VISIBILITY…NORTHEAST WINDS OF 20 TO 30 MPH WITH A FEW HIGHER GUSTS WILL CAUSE VISIBILITY RESTRICTIONS AND DRIFTING OF SNOW ON SATURDAY AND SATURDAY NIGHT.

* IMPACTS…HEAVY SNOW WILL MAKE TRAVEL DANGEROUS ACROSS THE WARNED AREA. THE FALLING SNOW…COMBINED WITH STRONG WINDS…WILL LEAD TO REDUCED VISIBILITIES. ROADS WILL LIKELY BECOME SLIPPERY AS THE WET SNOW FREEZES TO THE PAVEMENT.

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 YOU BECOME STRANDED.

CRAWFORD-CARROLL-GREENE-BOONE-STORY-AUDUBON-GUTHRIE-DALLAS-POLK-
CASS-ADAIR-MADISON-ADAMS-UNION-MONONA-HARRISON-SHELBY-POTTAWATTAMIE COUNTIES
336 PM CST FRI FEB 3 2012

...WINTER STORM WARNING IN EFFECT FROM MIDNIGHT TONIGHT TO 6 AM
CST SUNDAY...

THE NATIONAL WEATHER SERVICE IN DES MOINES HAS ISSUED A WINTER
STORM WARNING FOR HEAVY SNOW...WHICH IS IN EFFECT FROM MIDNIGHT
TONIGHT TO 6 AM CST SUNDAY. THE WINTER STORM WATCH IS NO LONGER IN
EFFECT.

* TIMING...A GRADUAL TRANSITION FROM RAIN TO SNOW WILL BEGIN LATE
  THIS EVENING INTO THE OVERNIGHT HOURS. MUCH OF THE WARNED AREA
  WILL SEE ALL SNOW BY EARLY SATURDAY MORNING. A NARROW BAND OF
  HEAVY SNOW IS EXPECTED TO SET UP ACROSS CENTRAL IOWA DURING THE
  DAY ON SATURDAY. SNOW WILL BEGIN TO DIMINISH SATURDAY EVENING.

* STORM TOTAL SNOW...SNOWFALL AMOUNTS FROM 4 TO 8 INCHES WITH
  LOCALLY HEAVIER AMOUNTS ARE POSSIBLE. 6 to 9 INCHES IS POSSIBLE OVER
  MONONA, HARRISON, SHELBY AND POTTAWATTAMIE COUNTIES. 
 * WINDS/VISIBILITY...NORTHEAST WINDS OF 20 TO 30 MPH WITH A FEW
  HIGHER GUSTS WILL CAUSE VISIBILITY RESTRICTIONS AND DRIFTING OF
  SNOW ON SATURDAY AND SATURDAY NIGHT.

* IMPACTS...HEAVY SNOW WILL MAKE TRAVEL DANGEROUS ACROSS THE
  WARNED AREA. THE FALLING SNOW...COMBINED WITH STRONG
  WINDS...WILL LEAD TO REDUCED VISIBILITIES. ROADS WILL LIKELY
  BECOME SLIPPERY AS THE WET SNOW FREEZES TO THE PAVEMENT.

A WINTER WEATHER ADVISORY WILL BE IN EFFECT FROM 6AM SATURDAY UNTIL
MIDNIGHT SATURDAY, FOR FREMONT & PAGE COUNTIES, AND FROM MIDNIGHT FRIDAY 
TO 6AM SUNDAY FOR RINGGOLD AND TAYLOR COUNTIES.