Area Forecast Discussion
Issued by NWS Sioux Falls, SD

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000
FXUS63 KFSD 292315
AFDFSD

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SIOUX FALLS SD
515 PM CST THU JAN 29 2015

.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 228 PM CST THU JAN 29 2015

SKIES WILL RAPIDLY CLEAR FROM WEST TO EAST LATE THIS AFTERNOON INTO
THIS EVENING AS MIXING DIES AWAY AND HIGH PRESSURE BUILDS INTO THE
AREA. HAVE COOLED LOW TEMPERATURES TONIGHT...ESPECIALLY IN THE EAST
WHERE RADIATIVE CONDITIONS WILL BE GOOD.

MODELS HINT AT A BAND OF CLOUDS DEVELOPING ALONG THE SOUTH DAKOTA
NEBRASKA BORDER AND GRADUALLY SHIFTING EAST THROUGH THE DAY ON
FRIDAY.  THE NAM IS MOST AGGRESSIVE WITH THIS...WHICH MAY IMPACT
WARMING SOME. REGARDLESS...925 HPA TEMPS WARM 7-10 C ACROSS THE AREA
THROUGHOUT THE DAY...AND WITH A FAVORABLE SOUTHWEST MIXING
WINDS...HAVE RAISED FORECAST HIGHS ESPECIALLY ACROSS SOUTH CENTRAL
SOUTH DAKOTA.

.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 228 PM CST THU JAN 29 2015

SEVERAL CHANCES FOR LIGHT SNOW ARE NOW PRESENTING THEMSELVES THROUGH
THE MEDIUM AND EXTENDED PORTIONS OF THE FORECAST. THE FIRST CHANCES
ARRIVE SATURDAY NIGHT INTO SUNDAY...WITH MODELS TRENDING A BIT
SLOWER ON THE ARRIVAL OF PRECIPITATION. PHASING WITH THE NORTHERN
STREAM AND SOUTHWESTERN CONUS ENERGY SEEMS TO HAVE IMPROVED WITH
THE MAJORITY OF HIGHER QPF FOCUSED SOUTH OF THE CWA. THERE STILL
APPEARS TO BE ENOUGH FORCING WITH NORTHERN STREAM SHORTWAVE TO
PRODUCE LIGHT SNOW INTO THE EVENING AND OVERNIGHT HOURS. SNOW
AMOUNT SHOULD REMAIN AN INCH OR LESS.

GIVEN STRATUS AND MIXY CONDITIONS OVERNIGHT...HAVE TEMPERED THE DROP
IN OVERNIGHT LOWS A BIT HEADING INTO SUNDAY. THE DOWNWARD SWING
MAY NOT BOTTOM OUT UNTIL MID-MORNING ON SUNDAY GIVEN COLD
ADVECTION ALOFT. SUNDAYS TEMPERATURES WILL BE THE COLDEST SINCE
JANUARY 12TH...WITH MOST AREAS STUCK IN THE TEENS.

PROGRESSIVE NORTHWESTERLY FLOW ALOFT BROUGHT IN PART BY UPPER
TROUGHING CENTERED JUST WEST OF HUDSON BAY...WILL KEEP PERIODIC
CHANCES FOR LIGHT SNOW IN THE FORECAST THROUGH NEXT WEEK. ONE WAVE
WILL RACE THROUGH THE AREA ON MONDAY...WITH WARM ADVECTION AHEAD OF
THE SYSTEM BUMPING TEMPERATURES UPWARD A BIT ON MONDAY. GFS IS
SLIGHTLY MORE DEVELOPED WITH THE WAVE...WHILE ECMWF IS WEAKER AND
FURTHER NORTH.  A COMPROMISE SOLN WOULD PLACE LOW END POPS OVER THE
NORTHEASTERN TWO THIRDS OF THE CWA ON MONDAY INTO MONDAY NIGHT.
AGAIN...ANY SNOW ACCUMULATIONS WOULD BE LIGHT.

A SLIGHTLY STRONGER SPOKE OF ENERGY WILL ROTATE AROUND THE LARGER
SYNOPTIC TROUGH BY LATE TUESDAY INTO WEDNESDAY. A SECONDARY WAVE IN
THE EASTERN PACIFIC WILL ALSO BECOME ABSORBED INTO THE FLOW REGIME.
GIVEN MODEL CONSISTENCY WITH THIS SYSTEM...HAVE BUMPED UP POPS. SNOW
AMOUNTS WOULD AGAIN BE ON THE LIGHT SIDE.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z FRIDAY EVENING)
ISSUED AT 515 PM CST THU JAN 29 2015

MVFR STRATUS PERSISTING ALONG/EAST OF THE JAMES RIVER VALLEY AT
THE START OF THE PERIOD SHOULD SLOWLY CLEAR THROUGH THE NIGHT...
WITH PRIMARY UNCERTAINTY REGARDING JUST HOW QUICKLY THIS WILL
OCCUR. HAVE SLOWED CLEARING A BIT FROM PREVIOUS FORECAST...BUT
STILL EXPECT KHON/KSUX TO CLEAR THIS EVENING AND KFSD BY MIDNIGHT.
VFR CONDITIONS EXPECTED TO DOMINATE ACROSS THE REGION ON FRIDAY.

&&

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

$$

SHORT TERM...
LONG TERM...DUX
AVIATION...JH


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