Area Forecast Discussion
Issued by NWS Sioux Falls, SD

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FXUS63 KFSD 031050
AFDFSD

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SIOUX FALLS SD
450 AM CST TUE MAR 3 2015

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 450 AM CST TUE MAR 3 2015

FORECAST CONTINUES TO EVOLVE THIS MORNING...AS MAIN SNOW BAND
APPEARS TO BE SETTING UP JUST NORTH OF OUR FORECAST AREA SO FAR
EARLY THIS MORNING. EXPECTATION IS STILL THAT THIS BAND WILL SAG
SOUTHEASTWARD INTO OUR FORECAST AREA THROUGH THE EARLY MORNING AS
THE STRONG MID LEVEL FRONT BEGINS TO SHIFT EAST AHEAD OF THE WAVE.
THE MAIN QUESTION BECOMES JUST HOW FAR SOUTHEAST SNOWFALL OF ANY
SIGNIFICANCE WILL GET...AND HOW MUCH IMPACT BLOWING SNOW WILL HAVE
AS A RESULT OF LOWER SNOW TOTALS. SHOULD STILL SEE A PERIOD OF
FAIRLY INTENSE SNOWFALL IN AREAS NORTH OF I-90 FOR A FEW HOURS THIS
MORNING...AS MID LEVEL TEMPERATURES COOLING INTO FAVORED DENDRITIC
GROWTH RANGE INTERSECT STRONG LIFT ABOVE THE MID LEVEL FRONT.
HEAVIEST SNOWFALL RATES EXPECTED JUST AHEAD OF STRONGEST WINDS...BUT
SHOULD LAY DOWN A QUICK 1.5-3 INCHES IN EXISTING BLIZZARD WARNING
FOR THOSE STRONG WINDS TO WORK WITH...SO OPTED TO KEEP WARNING IN
PLACE FOR NOW. CONDITIONS MAY IMPROVE A BIT EARLIER THAN CURRENT
HEADLINES...BUT DAY SHIFT CAN MONITOR AND CANCEL EARLY IF NEEDED.

SOUTH OF THE WARNING...TRIMMED SNOWFALL TO LESS THAN 2 INCHES OVER
MOST OF THE ADVISORY AREA...WITH AN INCH OR LESS ALONG/SOUTH OF I-90
FROM SIOUX FALLS INTO SOUTHWEST MINNESOTA. DECIDED TO TRIM A FEW
COUNTIES OUT OF THE ADVISORY SOUTH OF I-90 IN SOUTH DAKOTA...WHERE
WE HAVE LITTLE IF ANY EXISTING SNOW COVER...AND DO NOT EXPECT ENOUGH
NEW SNOW TO REALLY CAUSE VISIBILITY ISSUES BASED ON BLOWING SNOW
ALONE ONCE THE FALLING SNOW ENDS LATE THIS MORNING. SOUTHWEST MN A
LITTLE DIFFERENT STORY THOUGH...AS THERE IS AN EXISTING SNOW PACK...
PROBABLY ON THE ORDER OF 2-4 INCHES. WHILE THIS SNOW IS OLD ENOUGH
THAT IT SHOULD NOT BE LOFTED...IT DOES CREATE A SURFACE WITH LESS
FRICTION...SO ANY NEW SNOW COULD MOVE AROUND MORE EASILY THAN IN
AREAS SOUTHWEST OF SIOUX FALLS. THUS DECIDED TO LEAVE ADVISORY IN
PLACE THERE FOR THE LATE MORNING/AFTERNOON.

STILL HAVE SOME CONCERN ABOUT FREEZING DRIZZLE WORKING INTO OUR
SOUTH THIS MORNING...AND HAVE BEEN SEEING INDICATIONS OF THIS ON
RADAR OVER THE PAST HOUR OR SO IN AREAS SOUTH OF SIOUX CITY. STILL
NOT CONFIDENT THAT WE WILL SEE MORE THAN SPOTTY ICING...SO WILL HOLD
OFF ON HEADLINES FOR NOW. BUT WILL MONITOR CLOSELY THROUGH THE NEXT
FEW HOURS.

MODELS IN GOOD AGREEMENT IN TIMING THE WAVE AND ASSOCIATED LIFT EAST
OF OUR CWA BY 18Z...AND THUS BROUGHT AN END TO FALLING SNOW THROUGH
THE AREA MORE QUICKLY THAN PREVIOUSLY FORECAST. SHOULD SEE GRADUAL
CLEARING IN THE LATE AFTERNOON/EVENING WITH STRONG SUBSIDENCE BEHIND
THE DEPARTING WAVE.

TEMPERATURES REMAIN THE OTHER FOCUS THROUGH THE NEXT 24 HOURS.
STARTING OFF VERY MILD WITH READINGS IN THE MID-UPPER 20S. READINGS
DO NOT APPEAR TO BE CRASHING QUITE AS QUICKLY AS ANTICIPATED IN
AREAS TO OUR WEST WHERE WINDS HAVE PICKED UP...BUT SHOULD STILL SEE
READINGS BEGIN TO FALL OFF AFTER DAYBREAK IN OUR WEST...WITH COOLER
TEMPERATURES MARCHING STEADILY EASTWARD THROUGH THE AFTERNOON. MOST
AREAS SHOULD BE IN THE TEENS BY SUNSET...THEN CONTINUE DOWNWARD INTO
THE SINGLE DIGITS ABOVE/BELOW ZERO TONIGHT. WILL LIKELY NEED A WIND
CHILL ADVISORY ACROSS OUR NORTHEAST FOR LATER TONIGHT...BUT WITH
ONGOING HEADLINES...WILL LET THE DAY SHIFT ADDRESS THIS ONCE THE
SNOW/BLOWING SNOW BEGINS TO WIND DOWN LATER TODAY.


.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 450 AM CST TUE MAR 3 2015

AN UPPER LEVEL TROUGH AND SURFACE HIGH PRESSURE SLIDE INTO THE
NORTHERN PLAINS ON WEDNESDAY...AND WITH WEAK COLD AIR ADVECTION
CONTINUING THROUGH THE DAY TEMPERATURES WILL ONCE AGAIN BE MUCH
BELOW NORMAL. BREEZY NORTHWESTERLY WINDS WITH GOOD MIXING WILL MAKE
THE DAY EVEN MORE UNPLEASANT WITH WIND CHILLS BELOW ZERO. TAKING INTO
CONSIDERATION FRESH SNOW...MAINLY ACROSS OUR FAR NORTHERN
AREAS...LOOKING AT HIGHS IN THE SINGLE DIGITS TO AROUND 10 THROUGH
OUR NORTH AND EAST...TO MID TEENS THROUGH THE CENTRAL AND LOWER
MISSOURI RIVER VALLEY. WEDNESDAY NIGHT WILL BE THE COLDEST NIGHT OF
THE WEEK AS THE SURFACE RIDGE AXIS SLIDES THROUGH THE REGION AND
WINDS DROP OFF. LOWS LOOKING TO BE AROUND 10 BELOW THROUGH THE
HIGHWAY 14 CORRIDOR INTO THE IOWA GREAT LAKES AREA...TO JUST BELOW
ZERO THROUGH THE MO RIVER VALLEY.

HIGH PRESSURE MOVES EASTWARD ON THURSDAY AND WITH STRONG WARM AIR
ADVECTION WILL HAVE A CONSIDERABLE RECOVERY IN TEMPERATURES...WITH
HIGHS BACK INTO THE LOWER 20S NORTHEAST...TO THE MID AND UPPER 30S
FROM THE MO RIVER CORRIDOR WESTWARD. THIS WILL BE THE LEAD IN TO
MUCH WARMER TEMPERATURES INTO THE START OF NEXT WEEK. THE ECMWF
CONTINUES TO OFFER THE WARMEST SOLUTION THROUGH THE PERIOD WITH THE
GFS SOMEWHAT COOLER...ESPECIALLY BY THE END OF THE WEEKEND. TRENDED
TOWARD THE WARMER SOLUTION...WHICH WOULD PUT HIGHS INTO THE 40S AND
50S FOR MOST DAYS THROUGH THE PERIOD...EXCEPT SLIGHTLY COOLER ON
SATURDAY WITH THE PASSAGE OF A WEAK COLD FRONT. IT APPEARS TO REMAIN
DRY THROUGH THE EXTENDED.


&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1053 PM CST MON MAR 2 2015

VFR WILL PREVAIL IN THE NEAR TERM...BUT A BAND OF SNOW WILL MOVE
INTO THE HURON AREA DURING THE PRE DAWN HOURS TUESDAY...WITH A
STRONG WIND SHIFT TO THE NORTH AND NORTHWEST FOLLOWING BY DAY
BREAK. THE STRONG WIND ACROSS THE FORECAST AREA WILL HIT VERY
SUDDENLY...WITH FAIRLY LIGHT WINDS IN A PRE FRONTAL TROUGH AHEAD
OF THE COLD FRONT. BUT BEHIND THE FRONT...THE WINDS WILL RAPIDLY
INCREASE TO 30 TO 45 MPH AND LAST THAT WAY FOR AROUND 6 HOURS.
DURING FALLING SNOW...ESPECIALLY AT HURON...VISIBILITIES WILL BE
GREATLY REDUCED TUESDAY MORNING INTO THE LOWER END IFR CATEGORY.
THE SNOW WILL NOT BE AS GREAT AT SIOUX FALLS...AND CERTAINLY NOT
AT SIOUX CITY. THEREFORE VISIBILITY REDUCTIONS WILL LIKELY BE LESS
SEVERE AND MORE BRIEF. ONE THING TO KEEP AN EYE ON HOWEVER IS THE
POTENTIAL FOR LIGHT FREEZING DRIZZLE AT KFSD AND KSUX BETWEEN 09Z
AND 12Z TUESDAY. THIS HINGES ON STRATUS DEVELOPING AHEAD OF THE
COLD FRONT AND THERE IS A QUESTION AS TO HOW LOW ANY STRATUS WILL
FORM. BY TUESDAY AFTERNOON...CONDITIONS SHOULD BE MVFR UNDER
INSTABILITY CUMULUS WITH SLOWLY DECREASING WINDS.


&&

.FSD WATCHES/WARNINGS/ADVISORIES...
SD...BLIZZARD WARNING FROM 11 AM THIS MORNING TO 6 PM CST THIS
     EVENING FOR SDZ040.

     WINTER WEATHER ADVISORY UNTIL 3 PM CST THIS AFTERNOON FOR SDZ050-
     063-064.

     WINTER WEATHER ADVISORY FROM 10 AM THIS MORNING TO 5 PM CST THIS
     AFTERNOON FOR SDZ054>056-059>062.

     BLIZZARD WARNING UNTIL 3 PM CST THIS AFTERNOON FOR SDZ038-039-
     052-053-057-058.

MN...BLIZZARD WARNING FROM 11 AM THIS MORNING TO 6 PM CST THIS
     EVENING FOR MNZ071-072.

     WINTER WEATHER ADVISORY FROM 11 AM THIS MORNING TO 6 PM CST THIS
     EVENING FOR MNZ080-081-089-090-097-098.

IA...NONE.
NE...NONE.
&&

$$

SHORT TERM...JH
LONG TERM...JM
AVIATION...MJ



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