HYDROLOGIC OUTLOOK
Issue Date: 902 PM CST TUE DEC 22 2009
Expiration: 915 AM CST WED DEC 23 2009

/1002 PM EST TUE DEC 22 2009/
...RENEWED RISES ON AREA RIVERS POSSIBLE LATER THIS WEEK...
A VERY STRONG LOW WILL MOVE INTO NORTHEAST IOWA BY FRIDAY
MORNING. THIS WILL BRING A MIXTURE OF PRECIPITATION
TONIGHT...WEDNESDAY AND THURSDAY INTO NORTHERN ILLINOIS AND
NORTHWEST INDIANA. THE PRECIPITATION WILL BEGIN AS SNOW AND SLEET
OVERNIGHT AND WILL CHANGE TO FREEZING DRIZZLE. WE EXPECT FREEZING
RAIN WEDNESDAY NIGHT AND EARLY THURSDAY MORNING. THEN...RAIN WILL
FALL OVER THE AREA THURSDAY. THERE IS SNOW ON THE GROUND AND THE
ADDITIONAL 1 TO 2 INCHES OF RAIN WITH SNOWMELT WILL ADD SIGNIFICANT
RUNOFF TO AREA RIVERS. SOME LOCAL RIVERS AND CREEKS MAY RISE
THURSDAY AND FRIDAY.
SNOW DEPTHS WERE GREATEST WITHIN PORTIONS OF THE ROCK...UPPER
FOX...AND UPPER DES PLAINES RIVER BASINS WHERE DEPTHS WERE BETWEEN 4
AND 8 INCHES. WATER EQUIVALENT OF THE SNOWPACK IN THOSE AREAS WAS
AROUND 1 INCH. FURTHER SOUTH...SNOW DEPTHS WERE BETWEEN 2 AND 4
INCHES WITH WATER EQUIVALENTS GENERALLY BELOW ONE HALF INCH.
REPORTED FROST DEPTHS WERE BETWEEN 2 AND 4 INCHES. ALTHOUGH RIVERS
WERE CURRENTLY BELOW FLOOD STAGE...FLOWS WERE SLIGHTLY ABOVE
NORMAL.
A COMBINATION OF HEAVY RAIN AND SNOWMELT OVER FROZEN GROUND WOULD
RESULT IN RISES ON AREA STREAMS WITH SOME RISES POSSIBLY ABOVE FLOOD
STAGE.
RESIDENTS IN LOW LYING FLOOD PRONE AREAS ALONG AREA RIVERS AND
CREEKS SHOULD CONTINUE TO MONITOR THIS DEVELOPING WEATHER SYSTEM.
$$

HAZARDOUS WEATHER OUTLOOK
Issue Date: 524 AM CST WED DEC 23 2009
Expiration: 515 AM CST THU DEC 24 2009

/613 AM EST WED DEC 23 2009/
THIS HAZARDOUS WEATHER OUTLOOK IS FOR NORTH CENTRAL ILLINOIS...
NORTHEAST ILLINOIS AND NORTHWEST INDIANA.
.DAY ONE...TODAY AND TONIGHT.
FREEZING DRIZZLE AND SLEET...POSSIBLY MIXED WITH SNOW WILL
DEVELOP OVER PORTIONS OF NORTHWEST INDIANA THIS MORNING...AND
CONTINUE INTO THIS EVENING BEFORE CHANGING TO RAIN.
MIXED PRECIPITATION IS ALSO EXPECTED TO BECOME MORE WIDESPREAD
ACROSS MUCH OF NORTHERN ILLINOIS TODAY. SURFACE TEMPERATURES
OVER NORTHERN ILLINOIS WILL STAY AT OR JUST BELOW FREEZING
GENERALLY ALONG AND NORTH OF INTERSTATE 88...AND WEST OF THE CITY
OF CHICAGO. ICE ACCUMULATIONS OF UP TO A QUARTER INCH ARE EXPECTED
IN THESE AREAS BY THURSDAY MORNING.
SURFACE TEMPERATURES ARE EXPECTED TO WARM ABOVE FREEZING BY MIDDAY
THURSDAY...RESULTING IN A CHANGE OVER TO ALL RAIN OVER THE ENTIRE
FORECAST AREA.
.DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY.
A MORE SUBSTANTIAL AREA OF PRECIPITATION IS EXPECTED TO OVERSPREAD
THE AREA THURSDAY AFTERNOON AND CONTINUE MUCH OF THURSDAY NIGHT.
BY THIS TIME...PRECIPITATION WILL BE ENTIRELY IN THE FORM OF RAIN.
GIVEN THE POTENTIALLY HEAVY RAINFALL...COMBINED WITH MELTING SNOW
AND FROZEN GROUND...FLOODING OF RIVERS AND LOW LYING AREAS
APPEARS LIKELY.
COLDER AIR WILL THEN CIRCULATE AROUND THE STORM CENTER ALLOWING
PRECIPITATION TO CHANGE BACK TO LIGHT SNOW OR SNOW SHOWERS ON
CHRISTMAS DAY...WITH PERIODS OF LIGHT SNOW CONTINUING INTO SUNDAY
AS THE LOW CENTER DRIFTS OFF ACROSS THE MIDWEST.
WINTER WEATHER ADVISORIES ARE NOW IN EFFECT FOR PORTIONS OF THE
OUTLOOK AREA. PLEASE REFERENCE THE LATEST WINTER WEATHER
STATEMENTS FROM THE NATIONAL WEATHER SERVICE FOR THE LATEST
FORECAST INFORMATION.
A FLOOD WATCH HAS ALSO BEEN ISSUED FOR THE OUTLOOK AREA.
THIS STORM SYSTEM HAS THE POTENTIAL TO IMPACT TRAVEL DURING THE
CHRISTMAS HOLIDAY PERIOD. PERSONS PLANNING TRAVEL ACROSS THE
MIDWEST BETWEEN WEDNESDAY AND SATURDAY SHOULD MONITOR FURTHER
FORECASTS AND STATEMENTS FOR THE LATEST INFORMATION ON THIS
INTENSIFYING WINTER STORM.
.SPOTTER INFORMATION STATEMENT...
SPOTTER ACTIVATION WILL NOT BE NECESSARY THROUGH TONIGHT.
&&
COMPLETE FORECAST INFORMATION IS AVAILABLE ON THE NWS CHICAGO
WEBPAGE: WEATHER.GOV/CHICAGO
$$

FLOOD WATCH
Issue Date: 345 AM CST WED DEC 23 2009
Expiration: 600 AM CST FRI DEC 25 2009

...HEAVY RAIN AND FLOODING POSSIBLE THURSDAY AFTERNOON THROUGH
FRIDAY MORNING...
.A DEVELOPING WINTER STORM OVER THE SOUTHERN PLAINS WILL MOVE
NORTH TO IOWA BY FRIDAY MORNING. AFTER A PERIOD OF WINTRY
PRECIPITATION WEDNESDAY AFTERNOON INTO THURSDAY MORNING...WARM
MOIST AIR WILL SPREAD NORTH ACROSS THE AREA WITH PERIODS OF
HEAVY RAIN EXPECTED THURSDAY AFTERNOON AND THURSDAY NIGHT.
ILZ003>006-008-010>014-019>023-032-033-039-INZ001-002-010-011-019-
231745-
/O.NEW.KLOT.FA.A.0003.091224T1800Z-091225T1200Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
WINNEBAGO-BOONE-MCHENRY-LAKE IL-OGLE-LEE-DE KALB-KANE-DUPAGE-COOK-
LA SALLE-KENDALL-GRUNDY-WILL-KANKAKEE-LIVINGSTON-IROQUOIS-FORD-
LAKE IN-PORTER-NEWTON-JASPER-BENTON-
INCLUDING THE CITIES OF...ROCKFORD...BELVIDERE...WOODSTOCK...
WAUKEGAN...OREGON...DIXON...DEKALB...AURORA...WHEATON...CHICAGO...
OTTAWA...OSWEGO...MORRIS...JOLIET...KANKAKEE...PONTIAC...
WATSEKA...PAXTON...GARY...VALPARAISO...MOROCCO...RENSSELAER...
FOWLER
345 AM CST WED DEC 23 2009 /445 AM EST WED DEC 23 2009/
...FLOOD WATCH IN EFFECT FROM THURSDAY AFTERNOON THROUGH LATE
THURSDAY NIGHT...
THE NATIONAL WEATHER SERVICE IN CHICAGO HAS ISSUED A
* FLOOD WATCH FOR PORTIONS OF ILLINOIS AND INDIANA...INCLUDING
THE FOLLOWING AREAS...IN ILLINOIS...BOONE...COOK...DE KALB...
DUPAGE...FORD...GRUNDY...IROQUOIS...KANE...KANKAKEE...
KENDALL...LA SALLE...LAKE IL...LEE...LIVINGSTON...MCHENRY...
OGLE...WILL AND WINNEBAGO. IN INDIANA...BENTON...JASPER...LAKE
IN...NEWTON AND PORTER.
* FROM THURSDAY AFTERNOON THROUGH LATE THURSDAY NIGHT.
* HEAVY RAIN IS EXPECTED TO DEVELOP ACROSS NORTHERN ILLINOIS AND
NORTHWEST INDIANA BY THURSDAY AFTERNOON AND CONTINUE THROUGH
EARLY FRIDAY MORNING. STORM TOTAL RAINFALL AMOUNTS OF 1 TO 2
INCHES WILL BE COMMON. SOME AREAS MAY RECEIVE AS MUCH AS 3
INCHES BY FRIDAY MORNING.
* THE DEPTH OF THE CURRENT SNOW PACK RANGES FROM 5 TO 8 INCHES
OVER NORTHWEST ILLINOIS TO 1 TO 3 INCHES ACROSS NORTHWEST
INDIANA. AS THIS SNOW MELTS...COMBINED WITH THE EXPECTED HEAVY
RAIN...AND FROZEN GROUND CONDITIONS...RAPID RUNOFF AND RISES ON
AREA RIVERS ARE EXPECTED. SOME RIVERS MAY REACH OR EXCEED FLOOD
STAGE. FLOODING OF LOW LYING AND FLOOD PRONE AREAS WILL ALSO BE
POSSIBLE.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
A FLOOD WATCH MEANS THERE IS A POTENTIAL FOR FLOODING BASED ON
CURRENT FORECASTS.
YOU SHOULD MONITOR LATER FORECASTS AND BE ALERT FOR POSSIBLE
FLOOD WARNINGS. THOSE LIVING IN AREAS PRONE TO FLOODING SHOULD BE
PREPARED TO TAKE ACTION SHOULD FLOODING DEVELOP.
$$

WINTER WEATHER ADVISORY
Issue Date: 335 PM CST TUE DEC 22 2009
Expiration: 1200 PM CST WED DEC 23 2009

...WINTER STORM TO BRING FREEZING DRIZZLE TO PARTS OF THE AREA
TONIGHT...FOLLOWED BY SLEET AND FREEZING RAIN WEDNESDAY INTO
THURSDAY...
.LOW PRESSURE ASSOCIATED WITH A DEVELOPING WINTER STORM WILL LIFT
FROM THE SOUTHERN PLAINS INTO THE MISSISSIPPI VALLEY THROUGH
THURSDAY. WHILE THE TRACK OF THE STORM WILL KEEP HEAVY SNOWS WEST
OF THE AREA...WARM MOIST AIR FLOWING NORTH ACROSS NORTHERN
ILLINOIS AND INDIANA WILL RIDE UP OVER COLD AIR NEAR THE
GROUND...CREATING PERIODS OF FREEZING DRIZZLE...FREEZING RAIN...AND
SLEET ACROSS THE AREA. FREEZING DRIZZLE IS EXPECTED TO BEGIN LATE
THIS EVENING ACROSS AREAS ALONG AND SOUTH OF INTERSTATE 80...AND
MAY RESULT IN GLAZING ON ROADWAYS. A MORE SUBSTANTIAL AREA OF
PRECIPITATION WILL DEVELOP AND BEGIN MOVING INTO THE AREA FROM
THE SOUTH WEDNESDAY MORNING...AND IS EXPECTED TO RESULT IN A
PERIOD OF SLEET AND FREEZING RAIN FROM WEDNESDAY INTO THURSDAY
MORNING. FREEZING RAIN MAY RESULT IN UP TO A QUARTER INCH OF ICE
ACCUMULATION OVER PARTS OF THE WATCH AREA ESPECIALLY LATE
WEDNESDAY AND WEDNESDAY NIGHT. SURFACE TEMPERATURES WILL THEN RISE
ABOVE FREEZING FROM SOUTH TO NORTH BY MIDDAY THURSDAY...WITH
PRECIPITATION CHANGING TO RAIN OVER THE AREA BY THURSDAY
AFTERNOON.
ILZ032-033-039-INZ019-230545-
/O.NEW.KLOT.WW.Y.0014.091223T0300Z-091223T1800Z/
LIVINGSTON-IROQUOIS-FORD-BENTON-
INCLUDING THE CITIES OF...PONTIAC...WATSEKA...PAXTON...FOWLER
335 PM CST TUE DEC 22 2009 /435 PM EST TUE DEC 22 2009/
...WINTER WEATHER ADVISORY IN EFFECT FROM 9 PM CST /10 PM EST/
THIS EVENING TO NOON CST /1 PM EST/ WEDNESDAY...
THE NATIONAL WEATHER SERVICE IN CHICAGO HAS ISSUED A WINTER
WEATHER ADVISORY FOR FREEZING DRIZZLE...WHICH IS IN EFFECT FROM 9 PM
CST /10 PM EST/ THIS EVENING TO NOON CST /1 PM EST/ WEDNESDAY.
* TIMING...FREEZING DRIZZLE IS EXPECTED TO DEVELOP LATE THIS
EVENING AND CONTINUE THROUGH LATE WEDNESDAY MORNING.
* ACCUMULATIONS...ACCUMULATIONS OF ICE ARE EXPECTED TO BE VERY
LIGHT...HOWEVER ANY FREEZING DRIZZLE THAT FALLS WILL LIKELY
QUICKLY COAT UNTREATED SURFACES.
* HAZARDS...GLAZING OF ICE ON UNTREATED SURFACES.
* IMPACTS...FREEZING DRIZZLE WILL RESULT IN A GLAZING OF ICE ON
ROADWAYS...SIDEWALKS...AND OTHER UNTREATED SURFACES. THIS WILL
RESULT IN POTENTIALLY TREACHEROUS CONDITIONS ON ANY UNTREATED
SURFACES.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
A WINTER WEATHER ADVISORY MEANS THAT FREEZING DRIZZLE WILL RESULT
IN SLIPPERY ROADWAYS AND CAUSE TRAVEL DIFFICULTIES. BE PREPARED
FOR HAZARDOUS DRIVING CONDITIONS AND USE CAUTION WHILE TRAVELING.
$$