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000
FXUS63 KFSD 042150
AFDFSD

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SIOUX FALLS SD
350 PM CST WED DEC 4 2013

.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 349 PM CST WED DEC 4 2013

STRONG PV PUSH DEEPENING MID LEVEL LOW LIFTING TOWARD CENTRAL
MINNESOTA...WITH SURFACE WAVE STRENGTHENING ACROSS EXTREME SOUTHEAST
MINNESOTA. SIGNIFICANT SNOWFALL COMING TO AN END WITH FINAL TAIL OF
FRONTAL BAND PRECIPITATION WINDING DOWN ACROSS SOUTHWEST MINNESOTA...
WITH DRY SLOT ALOFT STARTING TO PUSH NORTHEAST ACROSS THE CWA.
LINGERING SNOWFALL IS LIKELY TO PRODUCE LITTLE IF ANY ADDITIONAL
ACCUMULATION...AND IT IS ACTUALLY THE WIND WHICH WILL CREATE THE
GREATEST WINTER HAZARDS IN THE SHORT TERM.  WEST TO NORTHWEST WINDS
HAVE BEEN INCREASING...WITH GUSTS TO 35 TO 40 MPH ACROSS THE FAR
WEST...AND THE WEAKER GRADIENT IN VICINITY OF INVERTED TROUGH
STARTING TO PULL EAST ACROSS THE FAR EAST. SEVERAL REPORTS OF
BLOWING SNOW ACROSS THE SOUTHWEST...WHERE SNOWFALL FROM 5 TO 7
INCHES WAS COMMON OVERNIGHT AND THIS MORNING. MOST ASOS OBSERVATIONS
CONTINUE TO INDICATE MORE OF AN AVERAGE OF AROUND A MILE
VISIBILITY...AND WEBCAMS SUPPORT THAT IN OTHER LOCATIONS...BUT SOME
AREAS OF BLOWING SNOW ARE LIKELY TO CONTINUE INTO THE EVENING AS
WINDS ARE NOT LIKELY TO DROP OFF A GREAT DEAL WITH CONTINUED LOW
LEVEL COLD AIR ADVECTION AND SUBSIDENCE ON ON BACK SIDE OF EXITING
WAVE.

TO KEEP SOMEWHAT SIMPLE...HAVE CONTINUED CURRENT WINTER HAZARDS...
MAINLY AS A RESULT OF WINDS INTO THE EVENING HOURS. AS CURRENT
HAZARDS SET TO EXPIRE AT 06Z...INTRODUCED A LONG TERM WIND CHILL
ADVISORY WHICH EXTENDS THROUGH FRIDAY...ENCOMPASSING ALL BUT THE FAR
SOUTHEAST CORNER OF THE AREA...WHICH FAILS TO REACH CRITERIA OVER
THIS EXTENDED PERIOD. WOULD PROBABLY NOT NEED THE FAR EASTERN AREAS
OF SOUTHERN FRINGES TONIGHT...AND APPARENT TEMPS TOMORROW DURING THE
DAY WILL NOT MAINTAIN CRITERIA...BUT FOR SIMPLICITY AND FACT THAT
EVENING THROUGH MORNING HOURS ARE LIKELY TO MAINTAIN SUB -20 VALUES
FOR EACH DAY.

THURSDAY A BLUSTERY AND COLD DAY ACROSS THE AREA. WITH 925 HPA TEMPS
A SOLID -18 TO -21C...ALONG WITH THE FRESH AND FAIRLY DEEP SNOWCOVER
FOR MOST...EXPECT THAT TEMPS WILL STRUGGLE QUITE A BIT...WITH HIGHS
IN THE MID SINGLE DIGITS TO LOWER TEENS...AT BEST SEVERAL DEGREES UP
FROM OVERNIGHT LOWS. DID NOT EXPLICITLY MENTION ANY FLURRIES...BUT
WITH TEMPS AS COLD AS THEY ARE...ANY CLOUD OF NOTE MAY FLITTER A
COUPLE OF FLURRIES ACROSS THE AREA.

.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 349 PM CST WED DEC 4 2013

WINDS BEGIN TO TAPER DOWN ON THURSDAY NIGHT AS HIGH PRESSURE BUILDS
INTO THE REGION AND THE GRADIENT RELAXES. WHILE LOW CLOUDS LOOK TO
HANG IN EARLY...RH TIME SECTIONS AND SOUNDINGS INDICATE CLOUDS
BREAKING UP LATER AT NIGHT. 925 MB TEMPERATURES JUST EITHER SIDE OF
20 BELOW ZERO C SETTLE INTO THE REGION BY THURSDAY NIGHT...AND WHILE
TEMPERATURES WILL REALLY PLUNGE...THEY WILL BE TEMPERED SOMEWHAT BY
WINDS JUST UNDER 10 KTS. EVEN SO...CONTINUED ON THE LOW SIDE OF
GUIDANCE WITH READINGS DROPPING TO AROUND 10 BELOW OVER SNOW COVERED
AREAS TO NEAR 0 IN OUR MOSTLY SNOW FREE SOUTHEASTERN ZONES.
FACTORING IN THE WIND...WIND CHILLS WILL BE RUNNING AROUND 25 TO 30
BELOW OVERNIGHT...EXCEPT IN THE FAR SOUTHEAST WHERE IT WILL BE
CLOSER TO 15 BELOW.

THE BRUNT OF THE COLDER AIR WILL BE SITUATED ACROSS THE REGION ON
FRIDAY AND FRIDAY NIGHT. WITH HIGH PRESSURE CONTINUING TO BUILD INTO
THE AREA...WINDS WILL BE RELATIVELY LIGHT DURING THE DAY...THEN
DROPPING OFF TO NEARLY CALM ON FRIDAY NIGHT. AGAIN WENT ON THE LOW
SIDE OF GUIDANCE FOR BOTH PERIODS...WITH HIGHS RUNNING GENERALLY
AROUND ZERO OVER MOST OF THE AREA...EXCEPT FOR THE MID/UPPER SINGLE
DIGITS IN OUR SOUTHEAST. TEMPERATURES SOMEWHAT TRICKY ON FRIDAY
NIGHT WITH INCREASING CLOUDS EXPECTED LATE...BUT WITH CALM WINDS
TEMPERATURES SHOULD DROP PRETTY QUICKLY...AND GOING FOR LOWS MID AND
UPPER TEENS BELOW ZERO OVER SNOW COVERED AREAS...TO SINGLE DIGITS
BELOW SOUTHEAST.

THE HIGH PRESSURE AXIS BEGINS TO SHIFT OFF TO THE EAST ON
SATURDAY...AND WITH ONLY SLIGHT MODERATION IN THERMAL PROFILES IT
WILL CONTINUE TO BE BITTERLY COLD UNDER MOSTLY CLOUDY SKIES. HIGHS
WILL STILL RANGE FROM NEAR ZERO IN THE NORTH TO AROUND 10 THROUGH
THE SIOUX CITY TO STORM LAKE CORRIDOR. BY SATURDAY NIGHT...BOTH THE
GFS/ECMWF/GEM IN DECENT AGREEMENT ON AN UPPER LEVEL WAVE BEGINNING
TO LIFT OUT OF THE 4 CORNERS REGION...WITH BROAD MIDLEVEL WARM AIR
ADVECTION/ISENTROPIC LIFT OVERSPREADING OUR AREA. WITH THIS...IT
LOOKS LIKE A PRETTY DECENT CHANCE OF LIGHT SNOW OVER THE CWA FOR
LATER SATURDAY NIGHT AND SUNDAY...PERHAPS CONCENTRATED IN THE SOUTH
AND EAST. SUNDAY WILL BE OUR MILDEST DAY OF THE NEXT FEW...IF IT CAN
BE CALLED THAT WITH HIGHS INTO THE LOWER TEENS IN SOME LOCALES.

FARTHER INTO THE EXTENDED...SOUTHERN STREAM AND NORTHERN STREAM
ENERGY PHASE UP JUST TO OUR EAST...WITH A REINFORCING SHOT OF COLD
AIR STREAMING INTO THE NORTHERN PLAINS BEHIND THE SYSTEM. THIS WILL
DROP TEMPERATURES BACK INTO THE SINGLE DIGITS FOR HIGHS ON MONDAY
AND TUESDAY...WITH LOWS BELOW ZERO.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1122 AM CST WED DEC 4 2013

VISIBILITIES WILL LINGER IFR WITHIN SNOWFALL ACROSS FAR EASTERN
SOUTH DAKOTA AND SOUTHWEST MINNESOTA...AND ALSO WHERE BLOWING SNOW
OCCURRING FROM THE JAMES VALLEY WESTWARD. GRADUALLY...THE MVFR TO
VFR CEILINGS WILL OVERTAKE THE AREA...AND VISIBILITIES WILL LIFT
THIS EVENING INTO VFR.


&&

.FSD WATCHES/WARNINGS/ADVISORIES...
SD...WINTER WEATHER ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR SDZ068-
     069.

     WINTER STORM WARNING UNTIL MIDNIGHT CST TONIGHT FOR SDZ038>040-
     050-052>067.

     WIND CHILL ADVISORY FROM MIDNIGHT TONIGHT TO 6 PM CST FRIDAY FOR
     SDZ038>040-050-052>069.

MN...WINTER WEATHER ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR MNZ089-
     090.

     WINTER STORM WARNING UNTIL MIDNIGHT CST TONIGHT FOR MNZ071-072-
     080-081-097-098.

     WIND CHILL ADVISORY FROM MIDNIGHT TONIGHT TO 6 PM CST FRIDAY FOR
     MNZ071-072-080-081-089-090-097-098.

IA...WINTER WEATHER ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR IAZ001-
     002.

     WIND CHILL ADVISORY FROM MIDNIGHT TONIGHT TO 6 PM CST FRIDAY FOR
     IAZ001-002.

NE...NONE.
&&

$$

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