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000
FXUS63 KFSD 060956
AFDFSD

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SIOUX FALLS SD
356 AM CST THU MAR 6 2014

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 346 AM CST THU MAR 6 2014

THE FIRST QUESTION AS FAR AS IMPORTANT WEATHER IS WHETHER OR NOT WE
NEED AN ADVISORY FOR THE BLOWING SNOW IN SOUTHWEST MN BACK TO
BROOKINGS SD...WHERE THE BEST SNOW FELL AND WHERE THE WINDS ARE
STRONGEST. WEBCAMS AND REPORTS FROM LAW ENFORCEMENT INDICATE FEW
VISIBILITY PROBLEMS BEING REPORTED THOUGH SNOW IS BLOWING OVER
ROADS. THE SOUTH SOUTHEASTERLY WINDS ARE NEARING THEIR PEAK BUT
PROBABLY WILL NOT GET THERE UNTIL A BIT AFTER DAYBREAK. BELIEVE
MENTION IN THE FORECAST AND HAZARDOUS WEATHER OUTLOOK WILL CONTINUE
TO BE ENOUGH AS WE DO NOT APPEAR TO BE THREATENING WIDESPREAD
PROBLEMS. THE WINDS THEMSELVES ARE GENERALLY BELOW WIND ADVISORY
CRITERIA...SOME WINDS NUDGING INTO THE BOTTOM OF THAT ZONES HAVE
BEEN REPORTED ALONG THE BUFFALO RIDGE BUT FEEL THIS IS NOT
CONSISTENT ENOUGH AREA WINDS TO WARRANT A HIGHLIGHT FOR THAT. WINDS
ARE NOT QUITE AS STRONG OUTSIDE THE BUFFALO RIDGE AREA...AND WINDS
SHOULD SHOW A SLOW DECREASE FROM THE WEST THIS AFTERNOON AND EVENING.

ANOTHER QUESTION RELATES TO CLOUD COVER...WHICH IS NOT REALLY MUCH
OF A PROBLEM ASIDE FROM THE FINE DETAILS NEAR THE EDGE OF THE
EASTERN CWA STRATUS DECK. THIS IS JUST ABOUT WHAT WE EXPECTED A DAY
AGO FOR THIS TIME. A COMBINATION OF HEATING AND DRYING IN THE STRONG
FLOW SHOULD SLOWLY ERODE THIS STRATUS FROM THE WEST SOUTHWEST DURING
THE DAYTIME HOURS. IT IS WORTH NOTING THAT MODEL RH PROJECTIONS SHOW
THE DECK WILL ACTUALLY BE ERODING FROM THE TOP...THIS HAS BEEN MOST
APPARENT ON THE RAP RH PROJECTIONS FOR H900/925/950 MB. A THICKER
DECK WOULD BE A LOT MORE STUBBORN BUT THIS ONE SHOULD BREAK UP
STEADILY. SKIES WILL TEND TO PARTLY CLOUDY AS HIGH CLOUDS COME AND
GO.

HIGH TEMPERATURES LOOK GOOD FOR TODAY AS WE HAVE BEEN CARRYING THEM
CONSIDERING THE EXISTING SNOW COVER...WITH EVERYBODY EXPECTED TO
BUST THE FREEZING MARK AND GETTING AS WARM AS 50 SOUTHWEST IN
GREGORY COUNTY.  COLD FRONT WILL ARRIVE TONIGHT. UPPER FORCING FOR
ANY PRECIPITATION LOOKS WEAK AND WILL ARRIVE LATE TONIGHT. A SLIGHT
CHANCE OF PRECIPITATION STILL LOOKS RIGHT BEFORE DAYBREAK FRIDAY
WITH MAINLY A FREEZING RAIN AND SLEET POTENTIAL. IF THIS POTENTIAL
DEVELOPS THERE WOULD BE PROBLEMS...BUT THERE IS VERY LITTLE IN
DECENT MODEL SUPPORT TO PUN THE PRECIPITATION DOWN ANY BETTERED AT
THIS TIME. IN THE MILD AIR NEAR AND AHEAD OF THE FRONT....LOWS
SHOULD BE IN THE MID 20S TO LOW 30S.

.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 346 AM CST THU MAR 6 2014

A COLD FRONT WILL WORK ITS WAY ACROSS THE AREA DURING THE DAY
FRIDAY. THUS MOST OF US WILL SEE STEADY OR SLOWLY FALLING
TEMPERATURES THROUGH THE DAY IN THE 20S AND 30S. PRECIPITATION
POTENTIAL WITH THE FRONTAL PASSAGE REMAINS A BIT UNCERTAIN. 0Z NAM
IS STRONGEST WITH THE MID LEVEL FRONTOGENESIS...AND IS ALSO QUICKER
WITH THE PV ANOMALY EXITING THE ROCKIES. THE INTERACTION OF THE TWO
LEADS TO HIGHER QPF SOUTH OF INTERSTATE 90. THE 0Z GFS AND ECMWF ARE
WEAKER WITH THE FRONT AND THE PV ANOMALY...RESULTING IN LESS
INTERACTION AND WEAKER LIFT...THUS ALLOWING THE DRY AIR TO MAINLY
WIN OUT. THE STRONGER FRONTOGENESIS FROM THE NAM IS POSSIBLE...AS IT
USUALLY CATCHES ON TO THAT FIRST WITH ITS HIGHER RESOLUTION. A
STRONGER FRONT WOULD INCREASE THE CHANCE WE SATURATE AND GET SOME
LIGHT PRECIPITATION EVEN FURTHER NORTH. HOWEVER FEEL THE SLOWER AND
WEAKER PV ANOMALY FROM THE GFS AND ECMWF IS MORE LIKELY...AS THE NAM
SEEMS LIKE AN OUTLIER AND CAN REALLY STRUGGLE WITH THE LARGE SCALE
DYNAMICS BEYOND 24 HOURS. THIS WOULD TEND TO LIMIT AND PUSH SOUTH
SOME OF THE HIGHER QPF VALUES SEEN ON THE NAM DURING THE AFTERNOON.
SO WILL GO WITH THE SLIGHTLY STRONGER FRONT BUT WEAKER LARGE SCALE
FORCING IDEA...WHICH RESULTS IN POPS PRETTY MUCH UNCHANGED FROM THE
PREVIOUS FORECAST...WITH HIGH CHANCE ALONG THE MISSOURI RIVER
CORRIDOR TAPERING AS YOU HEAD NORTH. THIS ALSO RESULTS IN A BLENDED
QPF...SLIGHTLY SKEWED TOWARDS THE DRIER SIDE OF THE SPECTRUM. WARM
AIR ALOFT INITIALLY MAY RESULT IN A LIGHT WINTRY MIX
INITIALLY...TRANSITIONING TO SNOW AS COLDER AIR WORKS IN AND WE WET
BULB. AMOUNTS WILL BE LOW THOUGH...MAINLY JUST A LIGHT COATING OF ICE
OR SNOW...MAYBE UP TO AROUND A HALF INCH OF SNOW ALONG THE MISSOURI
RIVER CORRIDOR. WILL NEED TO WATCH TRENDS THOUGH...AS IF THE NAM
VERIFIED SNOW AMOUNTS WOULD BE HIGHER IN OUR SOUTH...BUT AGAIN THIS
SEEMS LIKE A LOWER PROBABILITY EVENT AT THIS TIME.

IT WILL BE A COLD ONE FRIDAY NIGHT BEHIND THE FRONT WITH SINGLE
DIGITS AND TEENS COMMON. HIGH PRESSURE WILL BE OVERHEAD SATURDAY
RESULTING IN A PARTLY TO MOSTLY SUNNY DAY WITH LIGHT WINDS. THE COLD
LOW LEVELS WILL HANG ON...RESULTING IN HIGHS ONLY IN THE 20S AND
30S. HOWEVER THE WARMUP REALLY BEGINS ON SUNDAY INTO MONDAY. LOW
SPREAD AMONG ENSEMBLE MEMBERS...SUGGESTING HIGH CONFIDENCE IN THESE
WARMER TEMPERATURES. HOWEVER UNCERTAINTY IS INTRODUCED INTO THE
FORECAST FROM THE SNOWPACK AND HOW MUCH IT INHIBITS WARMING. GIVEN
THE DEEP SNOW COVER OVER SOUTHWEST MINNESOTA AND ADJACENT PORTIONS
OF NORTHWEST IOWA...THINK THEY WILL ONLY MAKE IT INTO THE 40S BOTH
DAYS. MORE UNCERTAIN ELSEWHERE...AS IT WILL DEPEND ON HOW MUCH
SNOWPACK WE LOSE OVER THE COMING DAYS. WITH THE MARCH SUN...MELTING
COULD BE PRETTY EFFICIENT...HOWEVER TODAY AND TOMORROW MAY TEND TO
STAY MAINLY CLOUDY...AND SATURDAY WILL BE COLDER...SO NOT SURE WHERE
WE WILL BE SNOWPACK WISE COME SUNDAY. THUS STAYED ON THE
CONSERVATIVE SIDE FOR NOW ON SUNDAY. DID WARM HIGHS ON MONDAY OVER
ALLBLEND THOUGH...AS MORE CONFIDENT THAT THE SNOW COVER WILL BE LESS
OF A FACTOR OUTSIDE OF OUR EASTERN AREAS. THUS 50S AND LOW 60S
SHOULD BE A GOOD BET ON MONDAY FOR THE SOUTHWEST HALF OF THE CWA.
HIGHS BOTH DAYS COULD END UP SEVERAL DEGREES WARMER THAN FORECAST
DEPENDING ON THE ABOVE SNOW COVER IMPACT THOUGH...SO WILL NEED TO
FINE TUNE FORECAST OVER THE COMING DAYS.

A COLD FRONT SHOULD PUSH ACROSS MONDAY NIGHT...BRINGING A RETURN TO
COOLER TEMPERATURES TUESDAY INTO WEDNESDAY. ALTHOUGH NOT THAT COLD
OF AIR BEHIND THE FRONT...SO AT THIS TIME LOOKS LIKE HIGHS COULD
STAY IN THE 30S AND 40S. NOTHING SIGNIFICANT...BUT COULD SEE SOME
LIGHT PRECIPITATION MONDAY NIGHT INTO TUESDAY MORNING WITH THE FRONTAL
PASSAGE. GIVEN THE WARMING AHEAD OF THE FRONT...PRECIPITATION TYPE
COULD BE EITHER RAIN OR SNOW...DEPENDING ON HOW QUICKLY THE LOW LEVEL
COLD AIR RETURNS BEHIND THE FRONT.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1045 PM CST WED MAR 5 2014

MVFR TO OCCASIONAL IFR CEILINGS OVER THE EASTERN PARTS OF THE CWA
THROUGH THE EARLY MORNING HOURS. EXPECT THESE CEILINGS TO
DISSIPATE A BIT AROUND SUNRISE BUT A DECENT CHANCE TO REFORM AS
WARMING ALLOWS A LITTLE MIXING AND THE POSSIBLE REDEVELOPMENT OF
MVFR CEILINGS. OTHERWISE...SOUTH WINDS WILL GUST TO 30 TO 35 MPH
FROM LATE MORNING INTO THE AFTERNOON...ESPECIALLY AT KFSD AND
KSUX.


&&

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

$$

SHORT TERM...
LONG TERM...CHENARD
AVIATION...08