Area Forecast Discussion
Issued by NWS Sioux Falls, SD

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000
FXUS63 KFSD 200939
AFDFSD

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SIOUX FALLS SD
339 AM CST SAT DEC 20 2014

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 335 AM CST SAT DEC 20 2014

MOIST SOUTHERLY LOW LEVEL FLOW WILL CONTINUE ACROSS THE REGION FOR
TODAY AND TONIGHT...AND WITH A STRONG INVERSION SITUATED ACROSS THE
AREA IT DOES NOT APPEAR THAT THE STRATUS WILL GOING ANYWHERE THROUGH
THE PERIOD. COULD GET SOME BREAKS THROUGH THE WESTERN JAMES RIVER
VALLEY IN THE AFTERNOON WHERE MOISTURE IS NOT QUITE AS DEEP...BUT
AREAS TO THE EAST WILL MOST LIKELY STAYED SOCKED IN WITH CLOUDS.
WITH THE CLOUD COVER...TEMPERATURES WILL AGAIN REMAIN FAIRLY STEADY
WITH HIGHS IN THE LOWER TO MID 30S. NOT MUCH CHANGE FOR
TONIGHT...WITH SOME FOG DEVELOPMENT AGAIN POSSIBLE...ESPECIALLY IN
AREAS TO THE WEST WHERE THERE MAY BE BREAKS IN THE CLOUDS. LOWS LOOK
TO BE IN THE 20S...WITH THE MILDEST READINGS FROM THE INTERSTATE 29
CORRIDOR EASTWARD WHERE CLOUDS WILL BE THICKEST. DID REMOVE MENTION
OF DRIZZLE IN OUR FAR SOUTHEASTERN IOWA ZONES FOR TONIGHT AS SIGNALS
FOR DRIZZLE LOOKED WEAKER IN THE NEWER MODEL RUNS.


.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 335 AM CST SAT DEC 20 2014

MILD SOUTHERLY FLOW WILL KEEP LOW LEVEL MOISTURE AND STRATUS IN THE
PICTURE FOR MUCH OF THE AREA ON SUNDAY AHEAD OF THE NEXT POTENT
STORM SYSTEM. EXPECT SCATTERED CLOUDS IN SOUTH CENTRAL SD IN THE
MORNING BEFORE MID AND HIGH CLOUDS PUSH INTO THE AREA IN THE
AFTERNOON...WHILE MOSTLY CLOUDY TO CLOUDY SKIES PREVAIL ELSEWHERE
FOR THE BETTER PART OF THE DAY. HIGHS WILL WARM TO ABOVE NORMAL
READINGS IN THE LOWER 30S TO NEAR 40.

UPPER LEVEL TROUGH BEGINS DIGGING INTO THE NORTHERN PLAINS SUNDAY
AFTERNOON. MODELS ARE TRENDING A BIT FURTHER NORTH WITH THE
EXCEPTION OF THE NAM WHICH WAS DISCARDED AS AN OUTLIER. THE TROUGH
SLOWS OVER OUR FORECAST AREA SUNDAY NIGHT AND DEEPENS TO A CUT OFF
LOW ON MONDAY. GENERAL CONSENSUS BRING THE STACKED LOW CENTER TO OUR
NORTHWEST INTO CENTRAL MINNESOTA...ALTHOUGH EACH MODEL SHOWS SOME
SLIGHT DIFFERENCES IN THE STRENGTH AND LOCATION. COOLER AIR BEGINS
WRAPPING BEHIND THE SYSTEM MONDAY AFTERNOON...WITH THE NEAR OR
SLIGHTLY ABOVE FREEZING TEMPERATURES DROPPING INTO THE 20S.
PRECIPITATION TYPES SUNDAY NIGHT AND MONDAY WILL CERTAINLY BE A
MIXED BAG OF RAIN...SLEET...AND FREEZING RAIN. BUT GIVEN THAT QPF
AMOUNTS REMAIN VERY LIGHT DURING THIS PERIOD...ICE ACCUMULATION
LOOKS TO BE LESS THAN 0.05 INCHES...MAINLY CENTERED ON THE NORTHERN
HALF OF THE FORECAST AREA. SNOW AMOUNTS WILL BE MINIMAL THROUGH
MONDAY BUT WITH COOLER AIR ALOFT AND AT THE SURFACE ARRIVING...A
TRANSITION TO ENTIRELY SNOW LATE MONDAY AFTERNOON AND MONDAY EVENING
IS EXPECTED.

THE SYSTEM WOBBLES NEAR THE UPPER MISSISSIPPI VALLEY
MONDAY NIGHT INTO TUESDAY BEFORE FINALLY PULLING AWAY FROM THE
REGION TUESDAY NIGHT. SNOW CHANCES PERSIST DURING THIS PERIOD BUT
AGAIN...IT LOOKS LIKE A PROLONGED LIGHT SNOWFALL WITH TOTAL
ACCUMULATIONS OF AROUND 1 TO 2 INCHES RIGHT NOW. GIVEN SOME TIMING
AND TRACK CONCERNS...THESE AMOUNTS CAN CERTAINLY CHANGE AS THE EVENT
DRAWS NEAR. WINDS WILL ALSO BECOME BREEZY FROM THE NORTHWEST MONDAY
AFTERNOON INTO TUESDAY.

NORTHWEST UPPER FLOW WEDNESDAY AND WEDNESDAY NIGHT BECOMES MORE
ZONAL ON CHRISTMAS DAY AHEAD OF THE NEXT UPPER SHORTWAVE. PARTLY TO
MOSTLY CLOUDY SKIES ARE EXPECTED WITH NEAR SEASONAL TEMPERATURES IN
THE MID 20S AND LOWER 30S WEDNESDAY AND THURSDAY. MODELS REMAIN
UNCERTAIN ON THE TRACK OF THE WAVE...BUT TIMING LOOKS TO BE THURSDAY
EVENING INTO FRIDAY WITH SOME LIGHT SNOWFALL. CONFIDENCE IS SOMEWHAT
LOW IN REGARDING THE TRACK SO DID NOT ADJUST FROM THE ALLBLEND
VALUES.


&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1104 PM CST FRI DEC 19 2014

POOR AVIATION CONDITIONS EXPECTED TO CONTINUE THROUGH THE PERIOD.
LARGELY STUCK WITH PERSISTENCE FORECAST OF IFR TO LOWER END MVFR...
WITH SOME SLIGHT LOWERING IN THE EARLY-MID MORNING...FOLLOWED BY
MARGINAL IMPROVEMENT DURING THE AFTERNOON/EVENING HOURS. PRIMARY
MODELS DO HINT AT STRATUS BREAKING UP MORE THAN INDICATED DUE TO
SOME MODEST MIXING WITHIN THE STRATUS LAYER. TOUGH CALL BUT OPTED TO
HOLD ONTO THE STRATUS FOR NOW. WESTERN EDGE OF STRATUS DECK LIKELY
TO SEE LOWER VISIBILITIES IN FOG THROUGH MID-MORNING THAN THOSE
AREAS BENEATH THE STRATUS...HOWEVER THIS SHOULD NOT AFFECT TAF
LOCATIONS AS STRATUS EXPECTED TO PERSIST THROUGH THE NIGHT AT KHON.


&&

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

$$

SHORT TERM...JM
LONG TERM...
AVIATION...JH


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