HYDROLOGIC OUTLOOK
Warning Issue Date: 339 PM CST TUE DEC 22 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: 408 PM CST TUE DEC 22 2009
...FREEZING RAIN ADVISORY IN EFFECT FROM 9 PM THIS EVENING TO
NOON CST WEDNESDAY...
...WINTER STORM WATCH NOW IN EFFECT FROM WEDNESDAY AFTERNOON
THROUGH FRIDAY AFTERNOON...
THE NATIONAL WEATHER SERVICE IN DES MOINES HAS ISSUED A FREEZING
RAIN ADVISORY...WHICH IS IN EFFECT FROM 9 PM THIS EVENING TO NOON
CST WEDNESDAY. THE WINTER STORM WATCH IS NOW IN EFFECT FROM
WEDNESDAY AFTERNOON THROUGH FRIDAY AFTERNOON.
...FREEZING RAIN ADVISORY...
* TIMING...FREEZING DRIZZLE WILL SPREAD SOUTHWARD WITH
TIME...INTO CENTRAL AND SOUTHERN IOWA BY LATE THIS EVENING.
* 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.
...WINTER STORM WATCH...
* TIMING...ALTHOUGH FREEZING DRIZZLE OR LIGHT FREEZING RAIN MAY
OCCUR THROUGH TONIGHT AND WEDNESDAY MORNING...THE MOST
SIGNIFICANT IMPACTS WITH THIS STORM SHOULD OCCUR FROM WEDNESDAY
AFTERNOON THROUGH FRIDAY.
* STORM TOTAL ICE ACCUMULATIONS...ICING OF UP TO ONE QUARTER OF AN
INCH IS EXPECTED THROUGH THURSDAY.
* STORM TOTAL SNOW ACCUMULATIONS...THE PRECIPITATION SHOULD BECOME
PRIMARILY SNOW LATE THURSDAY INTO FRIDAY WITH TOTAL
ACCUMULATIONS BY THE END OF THE STORM FROM 2 TO 6 INCHES FROM
ATLANTIC...DES MOINES AND GRINNELL...UP TO OVER A FOOT ALONG AND
WEST OF A DENISON...TO FORT DODGE...TO MASON CITY LINE.
* WINDS...BRISK EAST WINDS OF 15 TO 25 MPH WILL BE IN PLACE
THROUGH MUCH OF WEDNESDAY AND THURSDAY BEFORE INCREASING EVEN
FURTHER BY FRIDAY AND TURNING AROUND TO NORTH AND NORTHWEST. WINDS
BY THAT TIME MAY BE SUSTAINED AT 25 TO 35 MPH WITH GUSTS EVEN
HIGHER.
* VISIBILITY...DURING THE PERIODS OF HEAVY SNOW THURSDAY INTO
FRIDAY...VISIBILITIES WILL GENERALLY BE LESS THAN ONE MILE AND
EVEN DOWN TO A QUARTER MILE DURING THE HEAVIEST SNOWS. WITH
INCREASING WINDS AND SNOW COINCIDENT BY FRIDAY...BLOWING SNOW
AND GREATLY REDUCED VISIBILITIES NEAR BLIZZARD CONDITIONS ARE
EXPECTED BY THAT TIME.
* IMPACTS...TRAVEL WILL BECOME INCREASINGLY DIFFICULT IN THE WATCH
AREA ON WEDNESDAY DURING THE WINTRY MIX OF PRECIPITATION AND
CONTINUE TO BE DIFFICULT INTO THURSDAY AND FRIDAY AS SNOW
ACCUMULATES AND WINDS INCREASE. IN THE HEAVIEST SNOW AREAS...
TRAVEL MAY BECOME NEARLY IMPOSSIBLE DUE TO BLOWING AND DRIFTING
SNOW THURSDAY NIGHT INTO FRIDAY.
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.
$$
WINTER STORM WATCH
Warning Issue Date: 408 PM CST TUE DEC 22 2009
...FREEZING RAIN ADVISORY IN EFFECT FROM 9 PM THIS EVENING TO
NOON CST WEDNESDAY...
...WINTER STORM WATCH NOW IN EFFECT FROM WEDNESDAY AFTERNOON
THROUGH FRIDAY AFTERNOON...
THE NATIONAL WEATHER SERVICE IN DES MOINES HAS ISSUED A FREEZING
RAIN ADVISORY...WHICH IS IN EFFECT FROM 9 PM THIS EVENING TO NOON
CST WEDNESDAY. THE WINTER STORM WATCH IS NOW IN EFFECT FROM
WEDNESDAY AFTERNOON THROUGH FRIDAY AFTERNOON.
...FREEZING RAIN ADVISORY...
* TIMING...FREEZING DRIZZLE WILL SPREAD SOUTHWARD WITH
TIME...INTO CENTRAL AND SOUTHERN IOWA BY LATE THIS EVENING.
* 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.
...WINTER STORM WATCH...
* TIMING...ALTHOUGH FREEZING DRIZZLE OR LIGHT FREEZING RAIN MAY
OCCUR THROUGH TONIGHT AND WEDNESDAY MORNING...THE MOST
SIGNIFICANT IMPACTS WITH THIS STORM SHOULD OCCUR FROM WEDNESDAY
AFTERNOON THROUGH FRIDAY.
* STORM TOTAL ICE ACCUMULATIONS...ICING OF UP TO ONE QUARTER OF AN
INCH IS EXPECTED THROUGH THURSDAY.
* STORM TOTAL SNOW ACCUMULATIONS...THE PRECIPITATION SHOULD BECOME
PRIMARILY SNOW LATE THURSDAY INTO FRIDAY WITH TOTAL
ACCUMULATIONS BY THE END OF THE STORM FROM 2 TO 6 INCHES FROM
ATLANTIC...DES MOINES AND GRINNELL...UP TO OVER A FOOT ALONG AND
WEST OF A DENISON...TO FORT DODGE...TO MASON CITY LINE.
* WINDS...BRISK EAST WINDS OF 15 TO 25 MPH WILL BE IN PLACE
THROUGH MUCH OF WEDNESDAY AND THURSDAY BEFORE INCREASING EVEN
FURTHER BY FRIDAY AND TURNING AROUND TO NORTH AND NORTHWEST. WINDS
BY THAT TIME MAY BE SUSTAINED AT 25 TO 35 MPH WITH GUSTS EVEN
HIGHER.
* VISIBILITY...DURING THE PERIODS OF HEAVY SNOW THURSDAY INTO
FRIDAY...VISIBILITIES WILL GENERALLY BE LESS THAN ONE MILE AND
EVEN DOWN TO A QUARTER MILE DURING THE HEAVIEST SNOWS. WITH
INCREASING WINDS AND SNOW COINCIDENT BY FRIDAY...BLOWING SNOW
AND GREATLY REDUCED VISIBILITIES NEAR BLIZZARD CONDITIONS ARE
EXPECTED BY THAT TIME.
* IMPACTS...TRAVEL WILL BECOME INCREASINGLY DIFFICULT IN THE WATCH
AREA ON WEDNESDAY DURING THE WINTRY MIX OF PRECIPITATION AND
CONTINUE TO BE DIFFICULT INTO THURSDAY AND FRIDAY AS SNOW
ACCUMULATES AND WINDS INCREASE. IN THE HEAVIEST SNOW AREAS...
TRAVEL MAY BECOME NEARLY IMPOSSIBLE DUE TO BLOWING AND DRIFTING
SNOW THURSDAY NIGHT INTO FRIDAY.
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.
$$
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