Wind Chill Advisory 10, NWS Des Moines, IA

Adair County, IA, Adams County, IA, Appanoose County, IA, Audubon County, IA, Black Hawk County, IA, Boone County, IA, Carroll County, IA, Cass County, IA, Clarke County, IA, Crawford County, IA, Dallas County, IA, Davis County, IA, Decatur 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, Story County, IA, Tama County, IA, Taylor County, IA, Union County, IA, Wapello County, IA, Warren County, IA, Wayne County, IA

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE DES MOINES IA
1229 PM CST TUE FEB 19 2008

...UPDATED PUBLIC DISCUSSION.

.DISCUSSION...
SATURATION TAKING A BIT LONGER TO OCCUR AND HAVE PUSHED BACK START
TIME OF LIGHT SNOW A FEW HOURS INTO THE LATE AFTERNOON. STILL
LOOKING AT LIGHT SNOW EVENT WITH SOME WAA AND FORCING CROSSING THE
STATE. ARCTIC BOUNDARY DOWN TO ABOUT ST. CLOUD MN ATTM WITH STRONG
PUSH OF COLD AIR HEADING SOUTH FOR TNT. WITH AFTERNOON PACKAGE WILL
BE LEANING TOWARD A WC.W FOR THE FAR NORTH AND WC.Y FOR REMAINDER OF
THE AREA THROUGH 18Z WED. ALSO...WINDS WILL CONTINUE TO CAUSE
BLOWING SNOW OVER THE EASTERN PORTION OF THE FORECAST AREA AND WILL
MORE THAN LIKELY BE ADDING A BS.Y FOR AREAS EAST OF I35 THROUGH
ABOUT 9 AM WED CONSIDERING WIND SITUATION EXPECTED FOR MOST OF THE
NIGHT AND CONDITIONS ENCOUNTERED ACROSS THE REGION MON AFTERNOON./REV

PREVIOUS DISCUSSION...
SURFACE HIGH PRESSURE WILL SLIDE EAST THIS MORNING AHEAD OF A
CLIPPER SYSTEM THAT WILL BRING A QUICK SHOT OF SNOW. A WIND CHILL
ADVISORY CONTINUES UNTIL 6 AM THIS MORNING. CURRENT WIND CHILL
VALUES ARE BORDERLINE...BUT WILL LEAVE HEADLINES IN PLACE. SOUTHWEST
WINDS WILL ALLOW TEMPERATURES TO REBOUND INTO THE 20S ACROSS
SOUTHWEST SECTIONS TODAY. AFTERNOON SNOW AND CLOUDS WILL HOLD
READINGS DOWN IN THE TEENS NORTHWEST. SHORT RANGE MODELS ARE STILL
FAVORING THE NORTHEAST HALF OF THE FORECAST AREA FOR THE HIGHER QPF
AMOUNTS UP TO 0.05 INCHES. MOST LOCATIONS CAN EXPECT A LIGHT DUSTING
TO AROUND AN INCH...WITH ISOLATED TWO INCH AMOUNTS NOT OUT OF THE
QUESTION NORTHEAST. AN INCREASING NORTHWEST WIND TONIGHT WILL LIKELY
CREATE MORE PROBLEMS WITH SNOW DRIFTING ACROSS AND FREEZING ON
ROADWAYS. REDUCED VISIBILITIES IN BLOWING SNOW ARE ALSO POSSIBLE.
STRONG CAA WILL PLUNGE TEMPERATURES BELOW ZERO OVERNIGHT...AND A
SUSTAINED WIND OF 15 TO 25 MPH WILL PRODUCE WIND CHILL VALUES AROUND
20 BELOW SOUTH TO 30 BELOW NORTH. WILL LET DAY SHIFT FINE TUNE
DETAILS...INCLUDING CONSIDERATION OF WIND CHILL WARNING. THE ARCTIC
HIGH WILL SETTLE ACROSS IOWA ON WEDNESDAY WITH CONTINUED BITTERLY
COLD CONDITIONS. ATTENTION THEN TURNS TO THE SNOW POTENTIAL FOR
THURSDAY. MODEL CONSENSUS IS WEAK CONCERNING THE TIMING AND
AMPLITUDE OF THE UPPER LEVEL TROUGH. BUT FOR NOW IT APPEARS THERE IS
ENOUGH SUPPORT FROM THE GFS/GFSENS/ECMWF/GEM TO INCREASE AND EXPAND
COVERAGE OF CHC POPS...ESPECIALLY DURING THE DAY THURSDAY.
MODERATING TEMPS ARE STILL EXPECTED IN THE EXTENDED PERIOD WITH
MONDAY STILL FAVORED FOR THE ARRIVAL OF THE NEXT STORM.

&&

.AVIATION...19/18Z
UPPER LEVEL SYSTEM CONTINUES TO DROP SOUTH OUT OF THE NORTHERN
PLAINS AND WILL BRING CEILINGS LOWERING TO MVFR FOR A BRIEF PERIOD
AFT 20Z THIS AFTERNOON THROUGH APPROXIMATELY 01Z WITH A CHANCE OF
SNOW WITH MAINLY MVFR VISIBILITIES BUT A PERIOD OF IFR ALSO
POSSIBLE...ESPECIALLY NORTH. A COLD FRONT WILL SWEEP THROUGH LATE
AFTERNOON AND EARLY EVENING BRINGING GUSTY NORTHWEST WINDS BACK TO
THE STATE. SOME BLOWING SNOW POSSIBLE OVERNIGHT AND HAVE INCLUDED
MENTION ACROSS THE NORTHEAST TAF SITES OF KALO AND KMCW. POSSIBLE
BLOWING SNOW AT KOTM AS WELL AFT 06Z. WINDS WILL BE ISSUE WITH GUSTS
IN THE 25 TO 30 KT RANGE THIS EVENING AND OVN./REV

&&

.DMX WATCHES/WARNINGS/ADVISORIES...NONE

&&

SHORT TERM/AVIATION...REV
LONG TERM...KINNEY

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE DES MOINES IA
535 AM CST TUE FEB 19 2008

IAZ004>007-015>017-023>028-033>039-044>050-057>062-070>075-
081>086-092>097-201200-
EMMET-KOSSUTH-WINNEBAGO-WORTH-PALO ALTO-HANCOCK-CERRO GORDO-
POCAHONTAS-HUMBOLDT-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-
535 AM CST TUE FEB 19 2008

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF CENTRAL IOWA.

.DAY ONE...TODAY AND TONIGHT

BLOWING AND DRIFTING SNOW IS EXPECTED THIS EVENING...MAINLY IN
OPEN AREAS EAST OF HIGHWAY 169...AND NORTH OF INTERSTATE 80.
VERY SLICK ROAD CONDITIONS ARE EXPECTED AS SNOW DRIFTS ACROSS AND
FREEZES ON ROADWAYS. VISIBILITIES WILL ALSO DROP BELOW ONE MILE
AT TIMES IN BLOWING SNOW.

TEMPERATURES WILL FALL BELOW ZERO TONIGHT AND COMBINE WITH A
STRONG NORTHWEST WIND TO PRODUCE DANGEROUS WIND CHILL VALUES. WIND
CHILLS WILL RANGE FROM 20 BELOW ZERO IN SOUTHERN IOWA...TO 30 TO
35 BELOW IN THE NORTH.

.DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY

WIND CHILL VALUES OF 20 TO 35 BELOW ZERO WILL LINGER EARLY
WEDNESDAY MORNING...BEFORE GRADUALLY IMPROVING FROM LATE MORNING ON.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION WILL NOT BE NEEDED...ALTHOUGH REPORTS OF
SNOWFALL AMOUNTS...AND BLOWING AND DRIFTING SNOW ARE ENCOURAGED.

KINNEY