Area Forecast Discussion
Issued by NWS Sioux Falls, SD

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FXUS63 KFSD 050422
AFDFSD

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SIOUX FALLS SD
1022 PM CST WED MAR 4 2015

.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 352 PM CST WED MAR 4 2015

THE LAST BITTERLY COLD NIGHT FOR THE FORECAST PERIOD IS EXPECTED
TONIGHT BEFORE THE WARMING TREND FINALLY ARRIVES. ARCTIC HIGH
PRESSURE SLIDES SOUTHEAST ACROSS THE NORTHERN PLAINS
TONIGHT...MOVING OVERHEAD IN THE EARLY MORNING HOURS BEFORE SHIFTING
INTO THE MID MISSISSIPPI VALLEY THURSDAY AFTERNOON. BREEZY NORTHWEST
WINDS LATE THIS AFTERNOON WILL DROP BELOW 10 MPH THIS EVENING BEFORE
TURNING LIGHT AND VARIABLE OVERNIGHT WITH THE ARRIVAL OF THE HIGH
PRESSURE CENTER. WITH CLEARING SKIES EXPECTED AFTER
SUNSET...TEMPERATURES WILL DROP BELOW ZERO FOR MOST LOCATIONS. LOWS
WILL RANGE FROM AROUND ZERO IN SOUTH CENTRAL SD TO THE MID TEENS
BELOW ZERO IN EAST CENTRAL SD AND SOUTHWEST MINNESOTA. WIND CHILLS
DROP TO AROUND 20 TO 25 BELOW WHERE THE COLDEST AMBIENT READINGS
WILL BE FOUND...BUT GIVEN THAT WINDS WILL BE WELL UNDER 10
MPH...WILL HOLD OFF ON ISSUING ANY WIND CHILL HEADLINES.

RETURN FLOW ON THURSDAY BRINGS INCREASING SOUTHERLY WINDS THROUGH
THE DAY. WARM AIR ADVECTION BEGINS IN EARNEST IN ACROSS AREAS WEST
OF THE JAMES RIVER WHERE PLENTY OF SUNSHINE AND LITTLE TO NO
SNOWPACK WILL ALLOW TEMPERATURES TO MIX INTO THE MID 30S TO NEAR 40.
TO THE EAST...RECENT SNOWCOVER AND WEAKER WARM AIR ADVECTION WILL
LIMIT WARMING BUT WILL STILL BE AN IMPROVEMENT FROM TODAY. HIGHS
WILL MAINLY BE IN THE 20S.

.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 352 PM CST WED MAR 4 2015

STRONG SOUTHWEST WINDS ARE EXPECTED TO DEVELOP THURSDAY NIGHT WITH
WINDS INCREASING INTO THE 35-40 KNOT RANGE AT 925 HPA IN THE EVENING
HOURS ALONG THE BUFFALO RIDGE.  WITH ELEVATED AREAS REMAINING
SOMEWHAT MIXED...HAVE RAISED FORECAST LOWS...ESPECIALLY ALONG THE
BUFFALO RIDGE.

FRIDAY LOOKS TO BE THE FIRST OF SEVERAL WARMER DAYS AS 925 HPA TEMPS
WARM INTO THE SINGLE DIGITS ABOVE ZERO.  WITH LINGERING SNOW PACK
ACROSS THE NORTH AND EAST...WAS FAIRLY CONSERVATIVE IN WARMING NORTH
OF I-90 AND EAST OF I-29.

FRIDAY NIGHT MODELS SHOW A SHORTWAVE DROPPING DOWN IN NORTHWEST
FLOW.  TOUGH CALL IN TERMS OF WHERE TO PLACE ANY POTENTIAL POPS...AS
MOISTURE IS EXTREMELY LIMITED AND WAVE PLACEMENT IS SOMEWHAT
INCONSISTENT.  FOR NOW...FOCUSED POPS ACROSS NORTHEAST CORNER OF THE
FORECAST AREA CLOSEST TO WHERE THE MID LEVEL WAVE TRACKS IN BOTH THE
ECMWF AND NAM.  THE GFS IS FURTHER TO THE SOUTH AND WEST....TRACKING
CLOSER TO A KHON-KFSD-KSLB LINE.  PRECIPITATION TYPE IS ALSO QUITE
TRICKY...BUT GIVEN TIMING THINK ANY PRECIPITATION THAT FALLS WILL
MAINLY BE SNOW.

ANOTHER MOISTURE STARVED WAVE DROPS DOWN IN NORTHWEST FLOW ON
SUNDAY.  MODELS INDICATE COLD AIR ADVECTION BEHIND BOTH WAVES ON
SATURDAY AND SUNDAY...THOUGH THE STRENGTH OF THE COLD AIR REMAINS IN
QUESTION.  HAVE A 5 DEGREE C SPREAD IN THE 925 HPA TEMPS ON
SUNDAY...AND HAVE THEREFORE STUCK FAIRLY CLOSE TO SUPER BLEND
GUIDANCE OVER THE WEEKEND.

MILD CONDITIONS EXPECTED MONDAY THROUGH WEDNESDAY OF NEXT WEEK.
WITH 925 HPA TEMPS CLIMBING TO + 10 C OR MORE...HAVE SIDED TOWARDS
THE WARMER SIDE OF GUIDANCE WITH LIMITED SNOW PACK EXPECTED BY THEN.
STUCK CLOSER TO GUIDANCE ON WEDNESDAY AS FLOW NEAR THE SURFACE
STARTS TO TAKE ON A SOUTHEASTERLY FLAVOR.  WITH THE EASTERLY
COMPONENT...THE MIXING POTENTIAL DECREASES SOME ALONG WITH THE
INCREASED POTENTIAL FOR STRATUS.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1022 PM CST WED MAR 4 2015

VFR CONDITIONS EXPECTED TO PREVAIL THROUGH THE FORECAST PERIOD.
WITH DEEP ARCTIC AIRMASS IN PLACE...AND WEAK FLOW TO WEAK WARM
ADVECTION AT LOWER LEVELS TOWARD DAYBREAK AT KFSD AND KSUX...WILL
HAVE TO MONITOR FOR DEVELOPMENT OF SOME SHALLOW ICE FOG...PERHAPS
DUE TO MAN MADE INFLUENCE. TOO LOW PROBABILITY EVENT TO MENTION IN
TAFS AT THIS POINT.

&&

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

$$

SHORT TERM...
LONG TERM...
AVIATION...CHAPMAN



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