Area Forecast Discussion
Issued by NWS Sioux Falls, SD

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FXUS63 KFSD 262013
AFDFSD

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SIOUX FALLS SD
313 PM CDT THU MAR 26 2015

.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 313 PM CDT THU MAR 26 2015

CURRENT SHORT WAVE WILL MOVE OUT QUICKLY AND IN FACT IS IN
THE PROCESS OF DOING SO. SNOW AND MIXED SNOW/RAIN SHOULD END LATE
THIS AFTERNOON. IT IS WORTH NOTING THAT AREAS TO THE EAST OF THE
SNOW AREA WHERE RADAR SHOWS LIGHT PRECIPITATION UPSTAIRS ARE LOOKING
PRETTY DRY ON WEBCAMS.

A CLEARING TREND COMING IN FROM THE NORTHEAST WILL WEAKEN AS IT
PROGRESSES INTO THE SOUTHWEST PART OF THE AREA WITH LOW CLOUDS
DECREASING BUT MID AND HIGH LEVELS BEING MORE STUBBORN. LIGHT
NORTHERLY WINDS WILL TEND TO GO NORTHEAST TO EAST. DECENT
COOLING IS EXPECTED EAST AND LESS TO THE SOUTHWEST WITH LOWS IN THE
TEENS EAST TO THE 20S WEST.

A STRONG WARM ADVECTION PATTERN SETS UP ALOFT EARLY FRIDAY AND WITH
A DECENT SHORT WAVE APPROACHING...THIS WOULD SEEM TO BE A SETUP FOR
A BAND OF WIDESPREAD LIGHT PRECIPITATION. HOWEVER THE AIR BY ALL
MODELS DRIES A LOT BELOW MID LEVELS TONIGHT AND THIS WILL BE AN
INHIBITOR TO PRECIPITATION REACHING THE SURFACE FRIDAY...SLOWING IT
AT THE VERY LEAST. WILL PROGRESS POPS OF LOW CHANCE AT MOST FROM
WEST TO EAST OVER THE AREA. PRECIPITATION TYPE WILL BE SIMPLE WITH
NO ABOVE FREEZING WARM LAYER ALOFT THROUGH THE DAY. RAIN VERSUS SNOW
WILL THEREFORE DEPEND ON LOW LEVEL/SURFACE TEMPERATURES. WITH THESE
FAIRLY LOW POPS WILL ALLOW FOR SOME SNOW AT HIGHER THAN USUAL
SURFACE TEMPERATURES...SINCE IF ANY PRECIPITATION MANAGES TO REACH
THE SURFACE...THE MOISTENING PROCESS WILL INVOLVE QUITE A BIT OF
COOLING AS WELL AND BRING INSTANT COOLING OF A FEW DEGREES AT THE
SURFACE WITH THE ONSET OF ANY PRECIPITATION. BECAUSE OF THE DRY
AIR...AMOUNTS IF ANY SHOULD BE LIGHT...PRECIPITATION AND SNOW
POTENTIAL. HIGH TEMPERATURES FRIDAY SHOULD BE IN THE 30S EAST
TO 40S WEST...EXCEPT SOME 50S EXTREME SOUTHWEST WHICH WILL
MAKE IT 20 DEGREES WARMER THAN IN THE WET SNOW TODAY.

.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 313 PM CDT THU MAR 26 2015

FRIDAY NIGHT INTO SATURDAY MORNING WILL SEE A PASSING THREAT FOR
LIGHT SNOW BUT ACCUMULATIONS SHOULD BE MINIMAL...MAINLY A HALF AN
INCH OR LESS. A SOUTHERLY WIND WILL INCREASE LATE IN THE NIGHT INTO
SATURDAY BUT STILL EXPECTING TEMPERATURES TO DROP INTO THE MID TO
UPPER 20S IN MOST LOCATIONS.

SATURDAY WILL BE WINDY AND A LITTLE COOL AS THE SOUTH TO SOUTHEAST
WIND KEEPS THE LOW LEVEL AIR LOCKED IN A LITTLE LONGER THAN PREVIOUS
RUNS OF THE MODELS. AIMING FOR MAINLY 40S ALONG AND EAST OF
INTERSTATE 29 AND MAINLY 50S TO THE WEST. THERE SHOULD BE SOME 60S
WEST OF THE JAMES RIVER VALLEY.

ANOTHER WAVE WILL DROP SOUTHEAST SATURDAY NIGHT INTO SUNDAY MORNING
BUT SHOULD BE WARM ENOUGH FOR MAINLY RAIN. PROFILES DO HINT AT A
SMALL CHANCE FOR SNOW SO IF THIS TREND CONTINUES WILL NEED TO THROW
A LITTLE BETTER THREAT FOR SNOWFALL IN THE EASTERN CWA. OVERALL
STILL LEANING TOWARDS CHANCE POPS SINCE THIS IS A FAIRLY FAST MOVING
SYSTEM...BUT THE BETTER CHANCES SHOULD BE EAST OF INTERSTATE 29.
LOWS FROM THE MID 30S EAST TO THE MID 40S WEST.

WILL NEED TO KEEP AN EYE ON SUNDAY WHICH POSES A POTENTIAL FOR VERY
HIGH TO POSSIBLY RED FLAG CONDITIONS. AFTER A SMALL THREAT FOR
RAINFALL MOVES EAST OF THE AREA ON SUNDAY MORNING CLOUDS WILL
DECREASE AND NORTHWEST WINDS WILL INCREASE SIGNIFICANTLY. WIND GUSTS
TO 45 MPH NOT OUT OF THE QUESTION AND WHEN COUPLED WITH AFTERNOON
RELATIVE HUMIDITIES FROM ABOUT 20 PERCENT IN SOUTH CENTRAL SOUTH
DAKOTA TO 40 PERCENT IN SOUTHWEST MINNESOTA FIRE WEATHER WILL LIKELY
BE IN THE FOREFRONT. THE BIGGEST NEGATIVE TO THIS WILL LIKELY BE IF
THE FRONT IS A LITTLE COLDER THAN EXPECTED BUT RIGHT NOW HIGHS FROM
THE MID 50S TO LOWER 60S LOOKS REASONABLE.

IN THE OUTER PERIODS(MONDAY THROUGH THURSDAY)...MODEL OUTPUT STILL
SUGGESTING ABOVE NORMAL TEMPERATURES THROUGH THE PERIOD. THE LATEST
ECMWF ENSEMBLE OUTPUT ALSO SHOWS MOST MEMBERS AT OR ABOVE NORMAL
DURING THIS TIME. STILL SOME DISCREPANCY IN TIMING OF A WAVE ON OR
ABOUT WEDNESDAY WITH THE ECMWF AND CANADIAN FASTER THAN THE GFS.
OVERALL WITH THE WAVE NOW A LITTLE FARTHER NORTH THAN YESTERDAY THE
EFFECTS ON TEMPERATURES AND PRECIPITATION ARE NOT ALL THAT GREAT.
THE MAIN DIFFERENCE WOULD BE SLIGHTLY COOLER TEMPERATURES ON THE
ECMWF WEDNESDAY NIGHT INTO THURSDAY. OVERALL THREAT FOR
PRECIPITATION CONTINUES TO BE PRETTY LOW.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1249 PM CDT THU MAR 26 2015

MVFR TO IFR VISIBILITIES AND CEILINGS IN RAIN AND SNOW THROUGH 23Z
WILL BE CONFINED TO THE SOUTHWEST CORNER OF THE AREA WEST AND
SOUTH OF MHE AND WEST OF YKN. CONDITIONS WILL IMPROVE TO VFR AFTER
23Z. OUTSIDE OF THIS AREA INCLUDING TAF SITES GENERALLY VFR WITH
SOME CEILINGS 3-5K FEET. CEILINGS MAY LOWER TO 1-3K FEET FAR
WESTERN PART OF THE AREA AFTER 27/15Z.

&&

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

$$

SHORT TERM...
LONG TERM...08
AVIATION...



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