HYDROLOGIC OUTLOOK
Warning Issue Date: 339 PM CST WED DEC 23 2009
FLOODING RESULTING FROM SIGNIFICANT RAINFALL...ALONG WITH
SNOW MELT AND ICE JAMS...POSSIBLE WEDNESDAY AND THURSDAY...
A STRONG WEATHER SYSTEM WILL BRING THE POSSIBILITY OF FLOODING TO
CENTRAL AND SOUTHERN IOWA THROUGH THURSDAY. THE TYPE OF
PRECIPITATION WILL BE A MAJOR DRIVING FORCE IN THE FLOODING THREAT.
THE COMBINATION OF ABOVE FREEZING TEMPERATURES...ALONG WITH
SEASONALLY MODERATE TO HEAVY RAINFALL...WILL LEAD TO A POTENTIALLY
SIGNIFICANT AMOUNT OF SNOW MELT AND RUNOFF INTO AREA STREAMS.
LOCALIZED FLOODING MAY ALSO OCCUR IN OTHER AREAS...SUCH AS URBAN
AREAS...WHERE THE DRAINAGE SYSTEMS MAY BE IMPAIRED DUE TO SNOW AND
ICE CLOGGED INTAKES.
ANOTHER CONCERN IS BREAK UP ICE JAMS ON AREA RIVERS. ESTIMATED RIVER
ICE DEPTHS RANGE FROM 2 INCHES IN SOUTHEAST IOWA...TO 6 INCHES IN
CENTRAL IOWA. THE RUNOFF WILL LIKELY BE ENOUGH TO BREAK UP THE ICE
ESPECIALLY AS ONE MOVES SOUTHWARD. SINCE THE RIVER ICE IS
RELATIVELY THIN...THOUGH...ONLY MINOR...LOCALIZED PROBLEMS DUE TO
ICE JAMS ARE EXPECTED.
RIVERS MOST LIKELY TO BE AFFECTED INCLUDE THE CHARITON...DES
MOINES RIVER FROM DES MOINES DOWNSTREAM...AS WELL AS THE SOUTH
SKUNK...CEDAR CREEK...AND THE THOMPSON RIVERS. OTHER SMALLER
STREAMS AND CREEKS MAY ALSO BE AFFECTED.
KEEP CURRENT ON THE LATEST FORECASTS...INCLUDING POSSIBLE WATCHES
AND WARNINGS.
$$
ZOGG
FREEZING RAIN ADVISORY
Warning Issue Date: 1002 PM CST TUE DEC 22 2009
...FREEZING RAIN ADVISORY REMAINS IN EFFECT UNTIL NOON CST
WEDNESDAY...
A FREEZING RAIN ADVISORY REMAINS IN EFFECT UNTIL NOON CST
WEDNESDAY.
...FREEZING RAIN ADVISORY...
* TIMING...AREAS OF DRIZZLE AND FREEZING DRIZZLE WILL CONTINUE
ACROSS THE AREA INTO THE EARLY MORNING ON WEDNESDAY AS
TEMPERATURES REMAIN NEAR FREEZING. SOME MINOR GLAZING MAY OCCUR.
* TOTAL ICE ACCUMULATIONS...AROUND A TENTH OF AN INCH OF ICE
ACCUMULATION IS EXPECTED THROUGH MIDDAY WEDNESDAY.
* VISIBILITY...THE FREEZING DRIZZLE WILL COMBINE WITH AREAS OF
FOG TO REDUCE VISIBILITIES TO LESS THAN ONE MILE IN AREAS.
* IMPACTS...TRAVEL WILL BE HAZARDOUS WITH AREAS OF BLACK ICE...
ESPECIALLY ON LESS TREATED ROADS. IT WILL TAKE ONLY VERY MINOR
ICE ACCUMULATIONS TO CAUSE TRAVEL DIFFICULTIES. IN ADDITION...
THE ICE CAN BE DIFFICULT TO SEE ON THE ROAD...SO A ROAD THAT
APPEARS TO BE CLEAR MAY ACTUALLY BE ICY.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
A FREEZING RAIN ADVISORY MEANS THAT PERIODS OF FREEZING RAIN OR
FREEZING DRIZZLE WILL CAUSE TRAVEL DIFFICULTIES. BE PREPARED FOR
SLIPPERY ROADS. SLOW DOWN AND USE CAUTION WHILE DRIVING.
$$
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