Area Forecast Discussion
Issued by NWS Sioux Falls, SD

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FXUS63 KFSD 021744
AFDFSD

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SIOUX FALLS SD
1144 AM CST MON MAR 2 2015

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 429 AM CST MON MAR 2 2015

NOT MUCH TO DISCUSS FOR THE DAYTIME HOURS TODAY. EXPECT A MILD DAY
WITH INCREASING SOUTH WINDS AHEAD OF DEVELOPING WINTER STORM SYSTEM
WHICH WILL REALLY BEGIN TO IMPACT THE REGION TONIGHT. SHOULD SEE A
FAIR AMOUNT OF CLOUD COVER DEVELOP WITH MID LEVEL WARM ADVECTION
THROUGH THE DAY. NOT CONFIDENT IN MOISTURE BECOMING DEEP ENOUGH TO
SUPPORT MEASURABLE PRECIP AT THE SURFACE THOUGH. COULD SEE A FEW
FLURRIES OR SPRINKLES FROM THE MID CLOUDS... BUT EVEN POTENTIAL FOR
THAT LOOKING FAIRLY WEAK AT THIS POINT...SO HAVE REMOVED MENTION OF
PRECIP FOR TODAY. DESPITE THE INCREASE IN CLOUD COVER ANTICIPATED
TODAY...WITH 925MB TEMPS ABOVE FREEZING WORKING INTO OUR WESTERN
AREAS THINK MIXING WILL HELP WARM LOCATIONS ALONG/WEST OF THE JAMES
RIVER A FEW DEGREES HIGHER THAN YESTERDAY.

FOCUS FOR THE SHORT TERM REALLY ON TONIGHT...AND ALL MODELS APPEAR
TO BE WORKING THROUGH A TRANSITION PERIOD...SHIFTING STRONGER MID
LEVEL FRONTOGENESIS NORTHWARD AND BRINGING MID LEVEL DRYING INTO THE
SOUTHERN PORTIONS OF THE CWA. NOT MUCH EXPECTED THROUGH MUCH OF THE
EVENING AT THIS TIME...WITH STRONGEST LOW LEVEL WARM ADVECTION STILL
SOUTH OF THE FORECAST AREA...AND STRENGTHENING LOW-MID LEVEL FRONT
AHEAD OF THE MAIN WAVE JUST MOVING INTO CENTRAL SD BY 06Z. THUS HAVE
VERY LOW POPS ACROSS JUST OUR NORTHWEST THROUGH 06Z...WITH BULK OF
DEVELOPMENT EXPECTED IN THE 06Z-12Z WINDOW.

ALTHOUGH MODELS GENERALLY ON A NORTHWARD SHIFT OF THE MAIN PRECIP
BAND...IT IS A NORTHWARD SHIFT FROM THEIR RESPECTIVE PREVIOUS
LOCATIONS...WHICH STILL RESULTS IN A MODEST AMOUNT OF DISAGREEMENT
ON TIMING AND LOCATION OF THE HEAVIEST BAND OF SNOW WHEN ALL IS SAID
AND DONE. GFS REMAINS FASTEST IN PLOWING THE WAVE AND ASSOCIATED
SURFACE FRONT EASTWARD...WHILE THE NAM AND GEM LAG BY 4-6 HOURS.
ECMWF REMAINS SOMEWHERE IN THE MIDDLE...BUT WEAKER WITH THE LIFT AND
THUS LIGHTER WITH RESULTANT PRECIP AMOUNTS.

HAVE FOLLOWED THE BROAD TREND TO THE NORTH WITH THE HEAVIER PRECIP
AMOUNTS PRIOR TO 12Z...AND HAVE ALSO BOOSTED MAX AMOUNTS A BIT GIVEN
THE STRONG MID LEVEL FRONT TO SUPPORT DEEP LIFT. CURRENTLY LOOKS AS
THOUGH OUR FAR NORTHWEST MAY SEE SNOWFALL APPROACHING ADVISORY
LEVELS DURING THE LATTER HALF OF TONIGHT. HOWEVER...WITH LINGERING
UNCERTAINTY REGARDING THE LOCATION OF THE HEAVIER SNOW BAND...AND
EXPECTATION THAT STRONGEST WINDS WILL HOLD OFF UNTIL AFTER 12Z...
OPTED TO NOT ISSUE A SEPARATE ADVISORY HEADLINE FOR JUST SNOWFALL
PRIOR TO 12Z AT THIS TIME. INSTEAD WILL GIVE DAY SHIFT OPPORTUNITY
TO LOOK AT ANOTHER RUN OF THE MODELS TO SEE IF THEY TREND TOWARD A
BETTER CONSENSUS.

WITH THE NORTHWARD SHIFT OF THE MAIN LIFT/MOISTURE...WE ALSO HAVE A
SLIGHTLY FARTHER NORTHWARD PUSH OF DRYING IN THE MID LEVELS ACROSS
OUR SOUTH. THUS HAVE EXPANDED MENTION OF FREEZING DRIZZLE A BIT FOR
LATER TONIGHT...TO NEAR THE HIGHWAY 18 CORRIDOR FOR NOW...BUT COULD
BE EVEN A LITTLE FARTHER NORTH IF CURRENT TRENDS CONTINUE. TEMPS
WILL REMAIN ON THE MILD SIDE THROUGH TONIGHT AHEAD OF THE FRONT...
WITH MOST AREAS HOLDING IN THE 20S THROUGH 12Z.

.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 429 AM CST MON MAR 2 2015

THE INVERTED TROUGH/FRONTAL BOUNDARY SLIDES THROUGH THE REMAINDER OF
OUR CWA ON TUESDAY MORNING...AS THE MID LEVEL FRONT COLLAPSES TO THE
SOUTHEAST. WILL SEE MODERATE SNOW CONTINUING WITH THIS FORCING WITH
1 TO 2 INCHES OF ADDITIONAL ACCUMULATION ACROSS MUCH OF THE
AREA...BEFORE TRENDING DOWNWARD FROM THE WEST DURING THE EARLY
AFTERNOON AS THE FORCING WANES. MORE CONCERNING WILL BE
STRENGTHENING NORTHWESTERLY WINDS WHICH WILL QUICKLY RAMP UP BEHIND
THE FRONT WITH STRONG COLD AIR ADVECTION AND RAPID PRESSURE RISES.
BUFKIT SOUNDINGS SUGGEST 35 TO 45 KT WINDS AT THE TOP OF THE MIXED
LAYER...SO WITH GUSTS IN EXCESS OF 40 MPH POSSIBLE BLOWING SNOW WILL
BE AN ISSUE...MORE SO WHEN SNOW IS FALLING. IN LIGHT OF THIS...THE
CURRENT BLIZZARD WATCH SEEMED APPROPRIATE...EXTENDING ROUGHLY NORTH
AND WEST OF WAGNER TO SALEM SD...TO PIPESTONE TO WINDOM MN WHERE THE
HEAVIEST SNOW IS EXPECTED TO FALL. DID CONSIDER UPGRADING TO A
BLIZZARD WARNING FOR AREAS IN THE WATCH NORTH OF INTERSTATE 90...BUT
WITH SOME UNCERTAINTY ON SNOWFALL AMOUNTS WITH MODELS CONSISTENTLY
TRENDING NORTHWARD IN CONSECUTIVE RUNS...AND TO STAY IN
COLLABORATION WITH SURROUNDING OFFICES...ELECTED TO REMAIN WITH A
WATCH. AT LEAST PART OF THIS AREA WILL MORE THAN LIKELY BE UPGRADED
AT SOME POINT...WITH ADDITIONAL HEADLINES POSSIBLE IN SURROUNDING
COUNTIES DEPENDENT ON FUTURE MODEL TRENDS. WITH THE STRONG COLD AIR
ADVECTION TEMPERATURES WILL BE FALLING THROUGH THE DAY...WITH EARLY
MORNING HIGHS IN THE 20S FALLING INTO THE TEENS MOST PLACES BY LATE
AFTERNOON...WITH WIND CHILLS BELOW ZERO.

SHOULD SEE SOME DECREASE IN CLOUDS ON TUESDAY NIGHT AS THE SYSTEM
MOVES AWAY AND DRIER AIR FILTERS INTO THE REGION. WINDS WILL ONLY
SLOWLY FALL OFF THROUGH THE NIGHT...BUT WILL STILL SEE LOW
TEMPERATURES FALL TO JUST BELOW ZERO OVER MOST AREAS.

SURFACE RIDGING BEGINS TO BUILD INTO THE REGION ON WEDNESDAY. IT
WILL BE A BREEZY DAY...AND WITH FRESH SNOW COVER STAYED ON THE LOW
SIDE OF GUIDANCE WITH RESPECT TO TEMPERATURES THROUGH WEDNESDAY
NIGHT. THIS PLAYS OUT TO HIGHS IN THE SINGLE DIGITS...WITH SOME
TEENS THROUGH THE MISSOURI RIVER VALLEY...WITH OVERNIGHT LOWS FROM
ZERO TO -15.

THE HIGH MOVES OFF TO THE EAST ON THURSDAY WITH A SOUTHERLY FLOW
RETURNING TO THE REGION. THIS WILL BE THE BEGINNING OF A WARM
UP...WITH MUCH MILDER READINGS INTO THE UPCOMING WEEKEND. WHILE
HIGHS ON THURSDAY WILL BE IN THE 20S AND 30S...HIGH TEMPERATURES
WILL RISE INTO THE 30S AND 40S FOR FRIDAY THROUGH SUNDAY. IT LOOKS
TO REMAIN DRY THROUGH THE PERIOD.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1134 AM CST MON MAR 2 2015

VFR CONDITIONS EXPECTED THROUGH THIS EVENING. EXPECT STRATUS TO
DEVELOP OVERNIGHT TONIGHT...WITH THE POTENTIAL FOR PATCHY FREEZING
DRIZZLE AROUND KSUX. POTENTIAL FOR SNOW INCREASES FURTHER TO THE
NORTH...BUT HEAVIEST SNOW APPEARS TO BE NORTH OF KFSD. SNOW
LINGERS AT KHON TERMINAL AS WINDS INCREASE. FOR NOW...WENT
PREVAILING 3/4 SM VISIBILITY AT KHON...BUT COULD BE PERIODS OF
1/2SM VISIBILITY OR LESS AT KHON FROM 15-18Z TOMORROW.

&&

.FSD WATCHES/WARNINGS/ADVISORIES...
SD...BLIZZARD WATCH FROM TUESDAY MORNING THROUGH TUESDAY AFTERNOON
     FOR SDZ038>040-050-052>061-063-064.

MN...BLIZZARD WATCH FROM TUESDAY MORNING THROUGH TUESDAY AFTERNOON
     FOR MNZ071-072-080-081-097.

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

$$

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



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