000
FXUS63 KFSD 280459
AFDFSD

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SIOUX FALLS SD
1059 PM CST FRI FEB 27 2015

.UPDATE...
ISSUED AT 932 PM CST FRI FEB 27 2015

WILL HAVE TO UPDATE LOWS FOR SPENCER AND STORM LAKE IOWA TO AROUND
8 BELOW AND 5 BELOW RESPECTIVELY...HOWEVER THEY SHOULD THEN BOTTOM
OUT AND BEGIN TO MODERATE OVERNIGHT. OTHER LOWS STILL LOOK VERY
CLOSE AS TEMPERATURES BEGIN TO STEADY OUT.

&&

.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 244 PM CST FRI FEB 27 2015

MAIN CONCERN OVER THE NEXT 24 HOURS IS HOW FAST CLOUDS RETURN AND IF
THERE WILL BE ENOUGH MOISTURE TO GET SNOW IN NW BY LATE TOMORROW
AFTERNOON.

THE SFC RIDGE WILL MOVE OFF TO THE EAST LATE THIS EVENING. THIS WILL
KEEP SKIES CLEAR FOR MUCH OF THE NIGHT AS MOISTURE AND CLOUDS WILL
HAVE TO COME FROM KS AND WRN NE. IT WILL ALSO MEANS A INCREASE IN
WINDS OUT OF THE SOUTHEAST THROUGH THE NIGHT AS THE PRESSURE
GRADIENT TIGHTENS. ABOVE THE SURFACE...A SOUTHWESTERLY 20 TO 30 KT
LOW LEVEL JET WILL SET UP INTO SW MN. WITH A FAIRLY STRONG LOW LEVEL
INVERSION JUST ABOVE THE BUFFALO RIDGE EXPECT ENHANCED SW FLOW ON
THE EAST SIDE OF THE BUFFALO RIDGE TO AFFECT MARSHALL AND TRACY BY
LATE TONIGHT. SINCE IT IS NOT AN IDEAL SET UP...EXPECT WINDS AROUND
15 KTS WITH A FEW GUSTS INTO THE LOW 20S. AS FOR LOWS...IT WILL BE
CONTEST BETWEEN INCREASING WINDS AND RADIATIONAL COOLING. EAST OF
I29...RADIATIONAL COOLING SHOULD WIN WITH LOWS NEAR ZERO OR EVEN
BELOW ZERO...ALTHOUGH TEMPS ARE LIKELY TO BECOME STEADY OR EVEN
BEGIN TO RISE SOMETIME BETWEEN MIDNIGHT AND SUNRISE. FARTHER
WEST...INCREASING FLOW WILL LIMIT RADIATIONAL COOLING INTO THE
EVENING WITH A SLOW RISE EXPECTED AFTER MIDNIGHT. FOR THIS
REASON...EXPECT LOWS GENERALLY FROM 5 TO 10 ABOVE...WITH MANY PLACE
ABOVE 10 DEGREES BY SUNRISE.

A DISORGANIZED WAVE AND MID LEVEL FRONT WILL MOVE TOWARD THE AREA
SATURDAY. THE FIRST WAVE WILL MOVE THROUGH EARLY ON SATURDAY AND THE
MAIN EFFECT WILL BE TO BRING INCREASING CLOUDS INTO THE AREA. DURING
THE AFTERNOON...A 700 MB FRONT WILL TRY TO ORGANIZE BETWEEN I80 AND
HWY 20. THERE IS NOT A STRONG UPPER LEVEL FORCING FOR ASCENT SO
EXPECT THE PRIMARY IMPACT THROUGH THE AFTERNOON WILL BE THICKENING
CLOUDS. THERE IS A SMALL CHANCE OF LIGHT SNOW NEAR SUX AND SLB LATE
IN THE AFTERNOON...BUT GENERALLY EXPECT NO PRECIPITATION. AS FOR
HIGHS...AN APPROACHING FRONT COLD FRONT SHOULD BEGIN TO BRING WARM
AIR WEST OF I29. AND WITH AT LEAST SOME SUN...TEMPERATURES WILL RISE
INTO THE UPPER 20S AND 30S. WITH MORE CLOUDS AND LESS MIXING...HIGHS
WILL REMAIN IN THE LOW TO MID 20S ALONG AND EAST OF I29.

.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 244 PM CST FRI FEB 27 2015

AS THE ENERGY MOVES THROUGH ON SATURDAY NIGHT THERE IS JUST A BIT OF
AN UP TICK IN MOISTURE SO WILL KEEP SOME LOWER POPS IN SOUTHERN
PARTS OF NORTHWEST IOWA BUT THE REMAINDER OF THE CWA SHOULD BE DRY
AS MUCH DRIER AIR ALOFT SWOOPS IN. DID NOT STRAY TOO FAR FROM
GUIDANCE AS WINDS COULD BE A BIT FLAKY AS A WEAK TROUGH MOVES
THROUGH AND CLOUDS WILL BE ON THE PARTLY TO MOSTLY CLOUDY SIDE.

SUNDAY INTO SUNDAY NIGHT LOOKS DRY AS COLDER AIR SETTLES IN FROM THE
NORTH DURING THE EVENING. THIS SHOULD ALLOW FOR A RELATIVELY MILD
DAY...STILL BELOW NORMAL...THEN COLDER AT NIGHT AS HIGH PRESSURE
MOVES THROUGH. HIGHS IN THE 20S...SOME 30S ALONG THE MISSOURI RIVER.
LOWS AT NIGHT IN THE SINGLE DIGITS AND TEENS.

MONDAY NIGHT AND TUESDAY STILL HOLDS THE POTENTIAL FOR THE MOST
SIGNIFICANT PRECIPITATION EVENT. THE LATEST RUNS STILL SHOW MARGINAL
AGREEMENT AND THE MODELS FIGHT OVER THE EFFECTS OF THE NORTHERN
STREAM AND HOW QUICKLY PRECIPITATION WILL SHIFT SOUTH. QPF AMOUNTS
HAVE COME UP AND LOWER AND MID LEVEL FRONTAL FORCING LOOKS PRETTY
GOOD SO WILL GO WITH SOME HIGHER POPS AND IF AGREEMENT INCREASES
WILL PROBABLY NEED TO START TALKING ABOUT THE THREAT FOR SOME HIGHER
SNOW AMOUNTS IN THE SOUTHEASTERN HALF OF THE CWA. THE HINT FOR MIXED
PRECIPITATION NOT AS STRONG THIS TIME AROUND SO WILL CONTINUE TO
MENTION JUST SNOW.

BY TUESDAY NIGHT COLDER AND DRIER BEGINS TO SETTLE INTO THE REGION
AND THE BETTER CHANCES FOR SNOW PUSH SOUTH. LATE TUESDAY NIGHT INTO
WEDNESDAY MORNING COULD SEE SOME WIND CHILLS AROUND 20 BELOW WITH
HIGHS WEDNESDAY ONLY REACHING THE THE SINGLE DIGITS TO TEENS.

IN THE OUTER PERIODS (WEDNESDAY THROUGH FRIDAY)...A BROAD LARGE
SCALE TROUGH WILL MOVE TO THE EAST OF THE AREA AROUND THURSDAY WHICH
AT THIS TIME IS EXPECTED TO USHER IN A MORE SUSTAINED PERIOD OF
ABOVE NORMAL TEMPERATURES. FRIDAY COULD BE A TRANSITION DAY/MELTING
DAY SO WILL NOT GO TOO CRAZY WITH TEMPERATURES. THE REAL WARMING
LOOKS TO BE AFTER THIS ANYWAY SO WE WILL WAIT TO SEE IF THE MODELS
SHOW CONSISTENCY. FOR NOW THE DETERMINISTIC RUNS INDICATE LITTLE IF
ANY COLD AIR TO THE NORTH THAT COULD ADVECT SOUTH AND THE ENSEMBLE
OUTPUT SHOWS THAT EVEN THE COLDEST 10 PERCENT OF RUNS ARE ABOVE
NORMAL SO VIRTUALLY ALL RUNS OF THE ECMWF ARE ABOVE NORMAL.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1053 PM CST FRI FEB 27 2015

CONDITIONS WILL LIKELY BE VFR TONIGHT AND SATURDAY MORNING. IN
FACT SURFACE DEW POINT TEMPERATURES ARE DRY ENOUGH THAT MVFR MIGHT
NOT EVEN FORM AROUND SUNRISE SATURDAY...NOTING A DECENT SOUTH
BREEZE TO HELP KEEP THE AIR SLIGHTLY MIXED. THE QUESTION BEGINS
ABOUT MIDDAY SATURDAY AS MOISTURE STREAMS UP WITH A SHORT WAVE.
THE NAM AS USUAL SHOWS ABUNDANT SATURATION IN THE BOUNDARY LAYER
AT BOTH KFSD AND KSUX BY 18Z SATURDAY WHICH IS LIKELY NOT REAL.
THE NAM HAS STRUGGLED WITH THIS THE ENTIRE WINTER. THEREFORE OPTED
TO USE THE GFS WHICH SHOWS KFSD ON THE NORTHERN EDGE OF WHAT WILL
LIKELY BE SOME MVFR STRATUS. FOR NOW...KEPT KFSD JUST INSIDE THE
VFR CATEGORY SATURDAY AFTERNOON BEING FURTHER NORTH FROM THE SHORT
WAVE. SIOUX CITY WILL LIKELY BE A DIFFERENT STORY...AS THE GFS IS
SHOWING MVFR STRATUS FOR THAT AREA SATURDAY AFTERNOON AND LASTING
INTO THE EARLY EVENING.

&&

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

$$

UPDATE...MJ
SHORT TERM...SCHUMACHER
LONG TERM...08
AVIATION...MJ