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000
FXUS63 KFSD 022314
AFDFSD

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SIOUX FALLS SD
514 PM CST SUN MAR 2 2014

.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 333 PM CST SUN MAR 2 2014

ANOTHER COLD NIGHT ACROSS THE AREA AS THE ARCTIC HIGH PUSHES
THROUGH. EXPECTING GENERALLY LIGHT NORTHERLY WINDS...TURNING
SOUTHEASTERLY LATE AS THE HIGH BEGINS TO SHIFT EAST. A COUPLE
FACTORS MAKE TONIGHTS LOWS A BIT UNCERTAIN. FIRST IS A POTENTIAL
AREA OF CLOUDS AROUND 700 MB. EARLIER MODEL RUNS HAD SHOWN THIS AREA
OF CLOUDS MOVING INTO THE AREA...HOWEVER TRENDS ARE TO KEEP MOST OF
THIS CLOUD ACTIVITY NORTH OF THE CWA...MAYBE CLIPPING THE HIGHWAY 14
CORRIDOR AND INTO PORTIONS OF SOUTHWEST MINNESOTA...WITH JUST FEW TO
SCATTERED COVERAGE ELSEWHERE. THE OTHER THING TO WATCH WILL BE
INCREASING CIRRUS LATE...ALTHOUGH FEEL THIS WILL BE TOO HIGH AND
THIN TO IMPACT TEMPERATURES TOO MUCH. ALSO AS RETURN SOUTHERLY FLOW
PICKS UP LATE TONIGHT...WOULD EXPECT TEMPERATURES TO STEADY OFF AND
SLOWLY RISE...ESPECIALLY WEST OF THE JAMES RIVER. WENT WITH THE
COLDEST LOWS IN NORTHWEST IOWA...WHERE THE COMBINATION OF CLEAR
SKIES AND THE CALM WINDS SHOULD ALLOW READINGS TO DROP INTO THE LOW
20S BELOW ZERO. WARMEST READINGS WILL BE WEST OF THE JAMES...WHICH
WILL SEE RISING TEMPERATURES LATER TONIGHT AS WINDS INCREASE. GOING
WITH THE UPPER TEENS BELOW ZERO ALONG THE INTERSTATE 29 CORRIDOR.
GIVEN CLOUD COVER AND WIND UNCERTAINTY...DID NOT WANT TO GO TOO
LOW...ALTHOUGH IF THINGS COME TOGETHER COULD SEE SOME LOW 20S BELOW
ZERO READINGS THERE AS WELL.

WENT AHEAD AND ISSUED A WIND CHILL ADVISORY FOR THE WHOLE CWA
TONIGHT. WINDS WILL STAY UP JUST ENOUGH ALONG AND EAST OF INTERSTATE
29 THE FIRST HALF OF THE NIGHT TO PRODUCE WIND CHILLS OF 20 TO 30
BELOW ZERO. THEN AS SOUTHERLY FLOW BEGINS TO INCREASE LATE TONIGHT
INTO TOMORROW MORNING...WILL LIKELY SEE WIND CHILLS AGAIN IN THE 20
TO 30 BELOW RANGE FOR AT LEAST A FEW HOURS EVERYWHERE. SO WHILE
THERE MAY BE PERIODS WHERE CRITERIA IS NOT BEING REACHED...IT WILL
BE FRIGID...AND WIND CHILLS OF 20 BELOW OR COLDER SHOULD BE COMMON
ENOUGH TO WARRANT THE ADVISORY. HIGHS TOMORROW WILL BE IN THE SINGLE
DIGITS AND TEENS EAST...AND AROUND 20 WEST OF THE JAMES RIVER UNDER
AN INCREASING MID AND UPPER LEVEL CLOUD DECK. WARM AIR ADVECTION
WILL BE PRETTY STRONG...BUT THE SNOW COVER AND LOW LEVEL COLD DOME
SHOULD LIMIT OUR WARMING POTENTIAL. IT WILL BE A BIT BREEZY AS
WELL...WITH SOUTHERLY WINDS OF 10 TO 20 MPH...THUS WIND CHILLS WILL
AGAIN REMAIN BELOW ZERO THROUGH THE DAY.

.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 333 PM CST SUN MAR 2 2014

AS NOTED BY THE MID SHIFT...THE UPPER LEVEL JET STREAK AND
ASSOCIATED AREA OF LIGHT SNOW HAS SHIFTED PRIMARILY NORTH OF THE
MINNESOTA RIVER. WITH WEAK WARM ADVECTION AND A THERMAL
GRADIENT...HAVE KEPT A SLIGHT CHANCE OF SNOW ALONG HWY 14 INTO
MUCH OF SW MN AND THE IOWA GREAT LAKES FOR MONDAY NIGHT. SKIES
WILL BE OVERCAST MUCH OF THE HIGHT SO LOWS ARE EXPECTED TO REMAIN
ABOVE ZERO...PERHAPS ONLY FALLING TO 10 ABOVE IN SOUTH CENTRAL SD.

ON TUESDAY...THE ECMWF AND CANADIAN GEM BOTH SHOW A JET SREAK
MOVING SOUTHEAST FROM NORTH CENTRAL SD INTO SOUTHERN MINNESOTA.
THERE IS ALSO SOME MID LEVEL FRONTOGENESIS OVER THE AREA. THE
COMBINATION OF THE TWO IS EXPECTED TO RESULT IN SNOW
DEVELOPING...PERHAPS BY LATE MONDAY NIGHT IN CENTRAL SD AND THEN
MOVING INTO ERN SD...SWRN MN AND NWRN IA ON TUESDAY MORNING. AT
THIS POINT...THE BEST CHANCE OF SNOW IS EXPECTED TO BE NORTH OF A
LINE FROM HURON TO JACKSON MN. CURRENT THINKING IS THAT SNOWFALL
IN THIS AREA COULD BE 1 TO 3 INCHES. THE GEM SHOWS EVEN HEAVIER
PCPN BUT AT THIS POINT IT IS AN OUTLIER. TOWARD I90 IN SD COULD
SEE UP TO AN INCH ALTHOUGH LESS CONFIDENT IF ACCUMULATING SNOW
WILL GET SOUTH OF I-90 SO KEPT POPS FROM 20 PERCENT NEAR THE
MISSOURI RIVER TO 40 PERCENT AROUND SIOUX FALLS. DESPITE WARMING
TEMPERATURES ALOFT...THE CLOUDS AND EASTERLY FLOW WILL KEEP HIGHS
FROM THE MID TEENS IN SWRN MN TO THE MID 20S IN SOUTH CENTRAL SD.
850 MB TEMPERATURES ARE NEAR ZERO ALONG AND SOUTH OF I-90 AND DID
CONSIDER ADDING A CHANCE OF SLEET BUT MODEL SOUNDINGS SHOW THAT IF
IT DOES PRECIPITATE...THE AIR MASS COOLS BELOW ZERO AND THEREFORE
KEPT PRECIPITATION ALL SNOW.

THE SNOW SHOULD END TUESDAY EVENING IN SOUTHWEST MINNESOTA BUT
MOSTLY CLOUDY SKIES EXPECTED AS ANOTHER WAVE MOVES INTOTHE CENTRAL
PLAINS. THE WAVE WILL MOVE ACROSS NEBRASKA ON WEDNESDAY AND BRING
A SLIGHT CHANCE OF LIGHT SNOW AS FAR NORTH AS SIOUX CITY...YANKTON
AND STORM LAKE. IF SNOW DOES FALL...IT WILL ONLY BE A COUPLE OF
TENTHS OF AN INCH. EASTERLY FLOW WILL CONTINUE ON TUESDAY NIGHT
BUT IT WILL ALSO REMAIN CLOUDY SO THAT LOWS ARE AGAIN EXPECTED TO
BE FROM 5 ABOVE IN SOUTHWEST MINNESOTA...TO NEAR 12 ABOVE NEAR THE
MISSOURI RIVER. HIGHS ON WEDNESDAY WILL BE IN THE 20S TO LOWER 30S.

IN THE EXTENDED...MODEL SOLUTIONS DIVERGE BEGINNING WEDNESDAY AND
CONTINUING THROUGH THE WEEKEND. THE DIFFERENCE IN SOLUTION IS
DRIVEN BY HOW EACH MODEL HANDLES AN UPPER LOW OVER SOUTHWEST
CANADA. THE GFS IS VERY AGGRESSIVE WITH THE LOW AND DIVES IT INTO
THE NRN PLAINS BY WEDNESDAY NIGHT. THE GEM AND ECMWF AND MUCH LESS
AGGRESSIVE...WITH THE ECMWF SLOWEST. AS A RESULT...THE GFS DRIVES A
COLD FRONT THROUGH THE NRN PLAINS LATE WEDNESDAY NIGHT WITH MUCH
COLDER AIR IN PLACE BY THURSDAY. THE ECMWF...ON THE OTHER HAND...
DOES NOT BRING THE COLD FRONT THROUGH UNTIL THURSDAY NIGHT WITH
VERY WARM TEMPERATURE ON THURSDAY. THE CANADIAN IS BASICALLY IN
BETWEEN SLOWLY BRINGING THE FRONT THROUGH ON THURSDAY WITH THE
POTENTIAL FOR LIGHT MIXED PRECIPITATION. AT THIS POINT...HAVE
TRENDED MUCH CLOSER TO THE ECMWF BUT DID LOWER HIGHS A COUPLE OF
DEGREES THINKING THE COLD AIR MAY OOZE IN A BIT FASTER. DID NOT
ADD ANY PRECIPITATION FOR THURSDAY EXCEPT AROUND BKX. FOR
NOW...BASICALLY WENT WITH THE IDEA THAT AS THE FRONT MOVES THROUGH
THURSDAY NIGHT AND FRIDAY...THERE WILL BE SOME POST FRONTAL SNOW.
WITH TIMING AND LOCATION SO UNCERTAIN ONLY WENT 20 TO 30 PERCENT
AT THIS TIME. HOWEVER...THERE IS LOW CONFIDENCE IN WHEN AND WHERE
PRECIPITATION WILL OCCUR AND...WHILE NOT INCLUDED IN THE FORECAST
AT THIS TIME...SLEET OR FREEZING RAIN IS NOT OUT OF THE
QUESTION...ESPECIALLY IF PRECIPITATION DEVELOPS ON THURSDAY AND
THURSDAY NIGHT BEFORE COLD AIR MOVES IN ALOFT.

OTHERWISE...FRIDAY LOOKS TO BE MUCH BELOW NORMAL WITH HIGHS IN THE
20S TO LOWER 30S...WITH THE POTENTIAL FOR EVEN COLDER TEMPERATURES
IF THE COLD AIR COMES IN QUICKER. TEMPERATURES WILL BEGIN TO
RECOVER SATURDAY WITH BOTH THE GFS AND ECMWF SHOWING NORMAL TO
ABOVE NORMAL TEMPERATURES BY SUNDAY.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING)
ISSUED AT 513 PM CST SUN MAR 2 2014

VFR CONDITIONS EXPECTED THROUGH THE PERIOD. LIGHT NORTHERLY WINDS
TODAY WILL TRANSITION TO LIGHT SOUTHERLY TOMORROW WITH INCREASING
HIGH CLOUDS.

&&

.FSD WATCHES/WARNINGS/ADVISORIES...
SD...WIND CHILL ADVISORY UNTIL 10 AM CST MONDAY FOR SDZ039-040-055-
     056-061-062-066-067-070-071.

     WIND CHILL ADVISORY FROM 9 PM THIS EVENING TO 10 AM CST MONDAY
     FOR SDZ038-050-052>054-057>060-063>065-068-069.

MN...WIND CHILL ADVISORY UNTIL 10 AM CST MONDAY FOR MNZ071-072-080-
     081-089-090-097-098.

IA...WIND CHILL ADVISORY UNTIL 10 AM CST MONDAY FOR IAZ001>003-
     012>014-020>022-031-032.

NE...WIND CHILL ADVISORY UNTIL 10 AM CST MONDAY FOR NEZ013-014.

&&

$$

SHORT TERM...CHENARD
LONG TERM...SCHUMACHER
AVIATION...