392 
FXUS63 KFSD 231140
AFDFSD

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SIOUX FALLS SD
540 AM CST SUN FEB 23 2014

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 323 AM CST SUN FEB 23 2014

THERE ARE SOME MID TO HIGH CLOUDS ACROSS NEBRASKA EXTENDING INTO THE 
MISSOURI RIVER VALLEY OF SD AS WELL AS ALONG HIGHWAY 20 IN NW IOWA. 
THERE IS ALSO AN AREA OF MID CLOUDS NORTHWEST OF HURON. AS THESE 
CLOUDS HAVE MOVED INTO THE RIDGE AXIS THEY HAVE BEGUN TO DECREASE IN 
AREA AND TURN SOUTH AND EXPECT THAT TREND TO CONTINUE OVER THE NEXT 
FEW HOURS. ALSO HAVE MORE CIRRUS STREAMING EAST FROM SOUTHWESTERN 
SD. OVERALL EXPECT THAT SOUTH CENTRAL SD WILL BE MOSTLY CLOUDY TODAY 
WITH HIGH CLOUDS OVERHEAD...AND PARTLY CLOUDY SKIES IN THE JAMES 
VALLEY. TOWARD I-29 AND INTO SW MN AND MUCH OF NW IA...EXPECT SKIES 
WILL START MOSTLY SUNNY BUT AS THE AFTERNOON WILL SEE HIGH CLOUDS 
SLOWLY SPREAD EAST TOWARD I-29 AND THEN INTO NW IA. AS FOR 
WINDS...EXPECT NW WINDS TO CONTINUE THROUGH THE DAY WITH THE 
STRONGEST WINDS AROUND 15 MPH IN SW MN. BOTH ECMWF AND GFS SHOW 925 
MB TEMPERATURES 2-3C COLDER THAN YESTERDAY. BASED UPON 
THAT...LOWERED HIGHS BY 3-5 DEGREE INTO MID TO UPPER TEENS WHERE 
THERE IS SNOW COVER IN SW MN...EAST CENTRAL SD...AND NW IA. IN SNOW 
FREE AREAS...LOWERED HIGHS A COUPLE OF DEGREES INTO THE 20S.

A STRONG 700 MB FRONT BEGINS TO MOVE EAST TONIGHT AS UPPER WAVE 
MOVES OUT OF THE CANADIAN ROCKIES TOWARD THE NORTHERN PLAINS.  THE 
UPPER WAVE WILL REMAIN WELL NORTHWEST OF THE AREA THROUGH 12Z MONDAY 
BUT THE 700 MB FRONTOGENESIS WILL MOVE NORTH OF THE MISSOURI RIVER 
INTO SE SD AND WEST CENTRAL IA BY 12Z MONDAY. THE GFS SHOWS 
MARGINALLY UNSTABLE AIR ABOVE THE FRONT AND THERE IS AMPLE MOISTURE 
OVER THE FRONT. THERE IS A LOT OF DRY AIR AT LOW LEVELS AND IT WILL 
TAKE A FEW HOURS TO OVERCOME THIS DRY AIR LATER THIS EVENING. 
THEREFORE...DELAYED THE ONSET OF PRECIPITATION FOR MOST AREAS UNTIL 
AFTER MIDNIGHT. BUT AFTER MIDNIGHT...EXPECT FAIRLY RAPID SATURATION 
IN THE MISSOURI VALLEY WITH LIGHT TO MODERATE SNOW DEVELOPING. MAY 
SEE AN INCH OR MORE BY SUNRISE IN THIS AREA. FARTHER NORTH THE LIFT 
WILL BE WEAKER BUT LIGHT SNOW SHOULD SPREAD TOWARD HURON...MITCHELL 
...SIOUX FALLS...AND SIOUX CITY BY 12Z. OTHERWISE...WINDS WILL DROP 
OFF OVER MOST OF THE AREA IN THE EVENING...PICKING UP OUT OF THE 
EAST IN SOUTH CENTRAL SD AFTER MIDNIGHT. WITH LIGHT WINDS AND CLEAR 
SKIES PERSISTING EAST OF I29...TEMPERATURES COULD DROP FAST WHERE 
THERE IS SNOW COVER WITH MUCH OF SW MN DROPPING BELOW ZERO AROUND 
MIDNIGHT BEFORE CLOUDS MOVE IN AND TEMPERATURES BECOME STEADY OR 
EVEN SLOWLY RISE.

.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 323 AM CST SUN FEB 23 2014

THE CRUX OF THE SNOW WILL OCCUR ACROSS THE MAJORITY OF THE CWA DURING 
THE DAY ON MONDAY AS LOWER/MID LEVEL WARM AIR ADVECTION/ISENTROPIC 
LIFT OVERSPREAD THE AREA. THE STRONGEST MIDLEVEL FORCING WILL OCCUR 
THROUGH THE SOUTHWESTERN PORTION OF OUR CWA EARLY IN THE DAY...SO 
SNOW WILL MOST LIKELY BE A LITTLE HEAVIER OVER THIS AREA. REMAINED 
WITH A 17:1 SNOW RATIO...THOUGH WITH A DEEP DENDRITIC LAYER CANNOT 
RULE OUT HIGHER SNOW RATIOS...WHICH OF COURSE WOULD UP SNOW AMOUNTS. 
AT 17:1...WE ARE LOOKING AT TOTAL SNOWFALL AMOUNTS IN THE RANGE OF 3 
INCHES THROUGH MUCH OF THE JAMES RIVER VALLEY INTO THE LOWER SIOUX 
RIVER VALLEY...TRENDING UPWARDS TO NEAR 4 INCHES OVER SOUTH CENTRAL 
SOUTH DAKOTA. QPF AMOUNTS WILL TAPER DOWN TO THE EAST AS MIDLEVEL 
FRONTOGENESIS WEAKENS A BIT...BUT STILL LOOKING AT SNOWFALL TOTALS 
AROUND 2 INCHES OF ACCUMULATION IN THE FAR NORTHEASTERN/EASTERN CWA 
THROUGH THE BROOKINGS/MARSHALL/WINDOM/SPENCER/STORM LAKE CORRIDOR. 
NORTHEASTERLY/EASTERLY WINDS ARE EXPECTED TO REMAIN IN CHECK...SO 
THINKING THAT BLOWING SNOW WILL BE MINIMAL. IN THAT NORTHEASTERLY 
LOW LEVEL FLOW...TEMPERATURES WILL BE A COOLER ON MONDAY...RANGING 
FROM AROUND 10 OVER SOUTHWESTERN MINNESOTA TO AS WARM AS THE LOWER 
20S THROUGH THE MISSOURI RIVER CORRIDOR.

MODELS CONTINUE TO LINGER THE SNOW IN OUR EAST THROUGH MONDAY 
EVENING...THOUGH ANY ADDITIONAL ACCUMULATION SHOULD BE A HALF AN 
INCH OR LESS. CLOUDS WILL SLOWLY DECREASE OVERNIGHT...AND WITH COLD 
AIR ADVECTION AND FRESH SNOW COVER...WENT BELOW GUIDANCE WITH LOWS 
RUNNING CLOSE TO 10 BELOW ZERO THROUGH THE BROOKINGS TO MARSHALL 
AREA...TO NEAR ZERO THROUGH THE MO RIVER CORRIDOR INTO LOWER 
NORTHWEST IOWA. WINDS WILL STAY UP ENOUGH THAT WIND CHILL VALUES 
WILL DROP TO 20 TO 30 BELOW ZERO IN A LINE RUNNING ROUGHLY NORTH AND 
EAST OF HURON TO SIOUX FALLS TO SPENCER.

COLD AIR ADVECTION WILL CONTINUE ON TUESDAY AS SURFACE HIGH PRESSURE 
BUILDS INTO THE REGION. THIS WILL LEAD TO A MOSTLY SUNNY AND BREEZY 
DAY...WITH HIGHS SINGLE DIGITS NORTHEAST TO UPPER TEENS OVER FAR 
SOUTH CENTRAL SOUTH DAKOTA. WITH THE WINDS HOWEVER...WIND CHILL 
VALUES WILL HOVER BELOW ZERO ACROSS THE ENTIRE AREA DURING THE DAY. 
ON TUESDAY NIGHT...WITH LOWS DROPPING BELOW ZERO EVERYWHERE...WIND 
CHILL VALUES WILL REALLY PLUNGE...DROPPING AS LOW AS 30 TO 40 BELOW 
IN OUR NORTHEAST...AND IMAGINE THAT A HEADLINE WILL BE PUT OUT AT 
SOME POINT. AS HIGH PRESSURE SHIFTS OFF TO THE SOUTHEAST ON 
WEDNESDAY...A WEST/SOUTHWESTERLY LOW LEVEL FLOW WILL TAKE OVER 
DURING THE DAY...BRINGING SOME MODERATION IN TEMPERATURES AS HIGHS 
GET INTO THE MID TEENS IN SOUTHWESTERN MINNESOTA TO NEAR 30 IN SOUTH 
CENTRAL SOUTH DAKOTA.

NO RELIEF IN SIGHT FOR THE EXTENDED AS LOW PRESSURE ONCE AGAIN 
INTENSIFIES OVER EASTERN CANADA...KEEPING OUR AREA IN A STRONG 
NORTHWESTERLY UPPER LEVEL FLOW INTO THE END OF NEXT WEEK. THIS WILL 
RESULT IN TEMPERATURES MUCH BELOW NORMAL...SINGLE DIGITS AND TEENS 
FOR HIGHS AND LOWS FROM AROUND ZERO TO BELOW ZERO THROUGH THE 
PERIOD. MODELS ARE IN DISAGREEMENT WITH THE SPECIFICS OF 
PRECIPITATION POTENTIAL FOR THE END OF THE EXTENDED...BUT HINT AT 
THE ADDITIONAL POSSIBILITY OF LIGHT SNOW SOMETIME IN THE FRIDAY TO 
SATURDAY TIME FRAME.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 534 AM CST SUN FEB 23 2014

GENERALLY VFR CONDITIONS EXPECTED AT TAF LOCATIONS THROUGH 12Z
MONDAY. 

THERE WILL BE LIGHT SNOW MOVING INTO SOUTH CENTRAL SOUTH
DAKOTA AFTER 06Z MONDAY AND THIS SNOW WILL SPREAD NORTHEAST. SOUTH
OF K9V9 AND WEST OF KYKN...IFR CONDITIONS ARE LIKELY BY 12Z. SOME
SNOW MAY REACH KSUX BY 12Z AND CREATE MVFR OR EVEN IFR CONDITIONS
BUT EXPECTATION AT THIS POINT...IS THAT THE PROBABILITY OF LESS
THAN VFR CONDITIONS BY 12Z MONDAY IS LESS THAN 50 PERCENT SO ONLY
HAVE FLURRIES IN TAF AT THIS TIME. HOWEVER BETWEEN 12Z AND 18Z
MONDAY...KHON...KFSD...AND KSUX...LIKELY TO SEE MVFR OR IFR
CONDITIONS AS SNOWFALL DEVELOPS.

&&

.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
&&

$$

SHORT TERM...SCHUMACHER
LONG TERM...JM
AVIATION...SCHUMACHER