Area Forecast Discussion
Issued by NWS Des Moines, IA

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000
FXUS63 KDMX 111740
AFDDMX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DES MOINES IA
1140 AM CST THU FEB 11 2016

.SHORT TERM /TODAY/...
ISSUED AT 306 AM CST THU FEB 11 2016

NUMBER OF CHALLENGES FOR TODAY INCLUDING CLOUDS...TEMPERATURES AND
ONSET OF LIGHT SNOW OVER THE AREA. ARCTIC HIGH OVER MN CONTINUES TO
DRIFT SOUTH AND HAS FINALLY CLEARED CLOUDS OUT OF NORTHEAST IOWA AS
AREA OF SUBSIDENCE HAS TAKEN HOLD. MEANWHILE...LEE SIDE TROUGH
BEGINNING TO SHOW ON SUBJECTIVE SFC ANALYSIS OVER EASTERN WYOMING.
DEVELOPING WARM FRONT STRETCHES FROM SOUTHEAST WY TO NORTH CENTRAL
SOUTH DAKOTA EAST SOUTHEAST TO IA/NE/SD BORDER. MODELS DIFFER ON
DETAILS HANDLING TRACK OF SYSTEM TODAY/EARLY EVENING...BUT CONSENSUS
STILL POINTS TO BULK OF LIGHT SNOW TO OCCUR CENTERED MAINLY IN A
CORRIDOR BETWEEN A LINE FROM FORT DODGE...NEWTON ON THE NORTH TO
ATLANTIC TO LAMONI ON THE SOUTH SIDE OF THE CORRIDOR. AS THE WARM
FRONT NEARS...ISENTROPIC LIFT INTO H700 FRONTAL BOUNDARY WILL CREATE
LIGHT SNOW INCREASING INTO THE MID TO LATE AFTERNOON HOURS OVER
WESTERN TOWARD SOUTH CENTRAL IOWA. AMOUNTS INTO THE AFTERNOON HOURS
TO 00Z WILL LIKELY REACH AN INCH NEAR DENISON/CARROLL TO NEARLY A
HALF INCH IN THE METRO BY 00Z. THIS PUTS SOME LIGHT ACCUMULATION
ACROSS CENTRAL IOWA WITH THE POTENTIAL FOR SOME SLICK ROADS DURING
THE LATE AFTERNOON COMMUTE. SNOW WATER RATIO WILL BE PUSHING 13>15:1
OVER THE REGION BY LATE AFTERNOON. MOST OF THE LIFT WILL BE BELOW
THE DENDRITIC LAYER...SO SNOWFALL AMOUNTS WILL NOT BE AS PRODUCTIVE
AS COULD BE REALIZED.  EARLY MORNING TEMPERATURES HAVE DROPPED
QUICKLY TO NEAR/BELOW ZERO WITH CLEAR SKIES NORTHEAST. WITH CLOUDS
SLOWLY FILLING INTO THE AREA BY 15-19Z TODAY...NORTH WILL RECOVER
INTO THE MID TO UPPER TEENS WHILE THE SOUTH REACHES THE MID 20S.
WINDS WILL NOT BE A FACTOR IN THE FORECAST TODAY AND GENERALLY ABOUT
6 TO 10 MPH OVERALL.

.LONG TERM /TONIGHT THROUGH WEDNESDAY/...
ISSUED AT 306 AM CST THU FEB 11 2016

SIMILAR SETUP THIS EVENING AS WAS THE SETUP WEDNESDAY AM...WITH A
SHORTWAVE IMPULSE DROPPING THROUGH THE CWA IN NORTHWEST UPPER LEVEL
FLOW PATTERN. EXPECT TO SEE ANOTHER QUICK INCH OR SNOW ACROSS THE
CWA...WITH SLIGHTLY HIGHER AMOUNTS POSSIBLE BENEATH THE MAIN BAND
THAT SETS UP. UPPER LEVEL WAVE CURRENTLY ACROSS SRN SASKATCHEWAN AND
NRN MONTANA...AND WILL SLIDE THROUGH THE STATE PUSHING INTO THE OHIO
VALLEY REGION BY EARLY FRIDAY MORNING. THE ASSOCIATED SURFACE LOW TO
SLIDE ACROSS CENTRAL NE INTO MISSOURI OVERNIGHT TONIGHT...WITH SNOW
EXPECTED TO TAPER OFF ACROSS THE CWA BY LATE EVENING INTO THE
OVERNIGHT HOURS. HIGH RES MODELS TRYING TO BRING THE BAND A LITTLE
FURTHER WEST THAN CURRENT POPS IN PLACE WITH THE NAM-ARW A BIT
FURTHER EAST. NAM-ARW HAVING A BETTER CURRENT PLACEMENT...SO HAVE
STUCK WITH THE FURTHER EAST TRACK FOR THE POPS AND HIGHER BAND OF
SNOW FOR NOW. WAA EXPECTED TONIGHT...WITH THE WAVE...AND THEN CAA
THROUGH THE DAY FRIDAY. THIS SHOULD ALLOW FOR STEADY OR WARMING
TEMPS TONIGHT...WITH STEADY OR FALLING TEMPS FRIDAY. COLD ARCTIC
HIGH PRESSURE TO BUILD INTO THE REGION FOR FRIDAY NIGHT INTO
SATURDAY WITH DRY AND COLD CONDITIONS. GUSTY WINDS EXPECTED FRIDAY
AHEAD OF THE SFC HIGH BUILDING IN...WITH BUFKIT SHOWING MIXED
LAYER WINDS IN THE 25 TO 30KT RANGE. HAVE INCREASED NORTHERLY
WINDS FOR FRIDAY AND ADDED IN A MENTION OF PATCHY BLOWING SNOW
ACROSS THE NORTHERN CWA. STILL HAVE A DECENT SNOWPACK IN
PLACE...AND WILL HAVE THE LIGHT FLUFFY SNOW FROM WEDNESDAY AND
AGAIN TONIGHT AS WELL.

WITH THE COLD ARCTIC AIR IN PLACE FRIDAY NIGHT INTO SATURDAY...TEMPS
TO FALL TO AROUND ZERO SOUTH TO TEENS BELOW NORTH BY SATURDAY
MORNING. ADDITIONALLY WIND CHILLS EXPECTED TO BE IN THE 15 BELOW TO
30 BELOW RANGE SO WILL LIKELY NEED A WIND CHILL HEADLINE THEN.
OTHERWISE NEXT STRONGER SYSTEM TO DROP SOUTHEASTWARD THROUGH THE CWA
SATURDAY NIGHT INTO SUNDAY NIGHT...AS AN UPPER LEVEL SHORTWAVE
TROUGH DIGS INTO THE CENTRAL US. LIGHT TO MODERATE ACCUMULATIONS
EXPECTED AT THIS TIME...WITH THE HEAVIEST ACCUMULATIONS ALONG THE
IA/MN BORDER. SOME BREEZY CONDITIONS AGAIN SATURDAY NIGHT...SO HAVE
ADDED IN ANOTHER MENTION OF PATCHY BLOWING SNOW ACROSS THE NORTH.
UPPER RIDGING TO THEN BEGIN TO BUILD EASTWARD INTO THE CENTRAL US BY
THE MIDDLE OF NEXT WEEK. THIS WILL USHER IN A WARMING TREND...WITH
GUIDANCE VALUES SUGGESTING TEMPS IN THE UPPER 30S AND 40S TO
POSSIBLY AROUND 50 BY THE END OF NEXT WEEK.

&&

.AVIATION...11/18Z
ISSUED AT 1134 AM CST THU FEB 11 2016

CLIPPER SYSTEM WILL AFFECT AVIATION WEATHER DURING THIS FORECAST
PERIOD WITH LOW CEILINGS INCREASING ACROSS CENTRAL IOWA THIS
AFTERNOON AS WARM ADVECTION INCREASES. CEILINGS WILL INITIALLY BE
VFR BUT DROP TO MVFR/IFR AS SNOW APPROACHES AND THEN OCCURS OVER
MUCH OF THE AREA LATE THIS AFTERNOON INTO THIS EVENING. THE WORST
AVIATION CONDITIONS WILL BE FROM 00-06Z ACROSS CENTRAL IOWA WITH
REDUCTIONS TO BOTH VISIBILITIES AND CEILINGS DUE TO FALLING SNOW.
WINDS WILL REMAIN RELATIVELY LIGHT DURING THIS TIME LIMITING AND
BLOWING SNOW POTENTIAL. SNOW WILL END BY LATE TONIGHT WITH LOW
CEILINGS REMAINING BUT VISIBILITIES INCREASING. STRONG COLD
ADVECTION WILL ARRIVE ON FRIDAY MORNING WITH STRONG NORTHWEST
WINDS LEADING TO BLOWING SNOW BY LATE MORNING.

&&

.DMX WATCHES/WARNINGS/ADVISORIES...NONE.

&&

$$

SHORT TERM...REV
LONG TERM...BEERENDS
AVIATION...COGIL


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